JPH0438362Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus that has two or more developer storage chambers and is configured to develop an electrostatic latent image with a developer of a desired color.

In recent years, there has been a very strong demand for multicolor copying. However, full-color copying machines require complex mechanisms such as color separation filters, color misregistration correction, and intermediate transfer bodies, and are extremely expensive. Therefore, copying machines that can change the color of two-color copies by replacing the developing device have come into use. However, although there is a strong demand for two or more colors, black is the main color used in general documents, and the amount of other colors used is not as large as that of black. As a result, only black color is used more quickly, the developer is reinforced only with black, and other color developers are not replaced, resulting in inconveniences such as the developer becoming a little solidified when left for a long time.

The present invention aims to improve the above-mentioned prior art, and includes a rotating body, partitioning means for partitioning the interior of the rotating body into a plurality of developer storage chambers each storing a developer of a different color, and A plurality of developing members, which are provided in the storage chamber and carry and convey the developer to supply it to the electrostatic latent image holding member, and a developer storage chamber in which the rotating body is rotated and the developer of a desired color is stored. and a drive means for moving the image to the developing position.
An image forming apparatus characterized in that a developer storage chamber that stores black developer has a larger developer storage capacity than a developer storage chamber that stores other color developers. This reduces the number of times the frequently used black developer is replenished, improves ease of use for the user, eliminates coagulation of the less frequently used developer, and improves the image forming apparatus. This makes it possible to effectively utilize the space inside.

Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a cross section showing the outline of a copying machine.
A document placement glass 2 is provided on the top surface of the copying machine main body 1,
The original 3 placed on the glass 2 is irradiated with the light source 4 and the reflectors 5, 6, and 7, and the original image is transferred to the photoreceptor 10 as an electrostatic latent image holder by the short focus and small diameter imaging element array 8. Heslit exposure. Note that 9 is a heat insulating glass, which also corrects the color sensitivity of the photoreceptor. Around the photoreceptor 10, a charger consisting of a shield plate 11 and a charging wire 12 and a rotary developing device 1 are provided.
4. Transfer the visible image on the photoreceptor 10 to the transfer guide 16
A transfer charger 17 that transfers the image onto the paper P fed from the photoreceptor, and a cleaning device 18 that cleans the surface of the photoreceptor are arranged in this order.

The above paper P is fed from the cassette 19 to the paper feed roller 20.
The guide plates 16, 21,
22, the photoreceptor 1 is guided by a pair of rollers 23;
0 and the transfer charger 17, and the guide plate 2
4. The paper P is discharged onto the discharge tray 27 via a pair of fixing rollers 25 and a pair of delivery rollers 26, and a permanent visible image is formed on the paper P.

As shown in FIGS. 2 to 6, the rotary developing device 14 is composed of an outer casing 29 having a developing port 28 in the longitudinal direction, and a rotating body 30 rotatably mounted within the outer casing. . This rotating body has both end plates 31a and 31b partitioned by radial partition plates 32a to 32c as partition means, and each partition chamber 33a to 3
Developing rollers 34a to 3 as developing members are provided in 3c.
4c and toners 35a to 3 on the circumferential surface of this developing roller.
Blades 36a-36 for applying 5c in a uniform thin layer
c, and scrapers 37a to 37c as shielding members that are separated from the developing roller when the developing roller faces the developing port 28 and are connected to the developing roller when the developing roller is in another position, A developing device is configured for each of the partition chambers 33a to 33c. Here, the partition chambers 33a to 33c are storage chambers for storing developers, and the developer storage chamber 33a is a black developer, the developer storage chamber 33b is a sepia color developer, and the developer storage chamber 33a is a black developer;
A blue developer is stored in c. The developer storage chamber 33a has twice the amount of developer that can be accommodated in the developer storage chambers 33b and 33c.

A rotating shaft 38 of the rotary body 30 penetrates the outer casing 29 and protrudes to the outside, and a gear 39 attached to this protruding portion meshes with a gear 41 attached to a first driving shaft 40 of the copying machine main body. . Further, shafts 34a-a to 34c-c of the developing rollers 34a to 34c
passes through the end plate 31a, and a gear 42a is installed in the penetrating portion.
~42c are installed respectively. On the other hand, a gear 44 attached to the second driving shaft 43 of the copying machine body enters the outer casing 29 through a hole 45 made in the end plate of the outer casing 29, and is attached to the developing roller shaft at a position facing the developing port 28. The gears are designed to mesh. Reference numeral 46 denotes an internal gear fixed to the copying machine main body or the outer casing 29, and is provided at a position where the gear of the developing roller shaft immediately before moving to the position facing the developing port 28 by the rotation of the rotating body 30 meshes with the gear. ing.

Hereinafter, the state of each developing device in each position of the rotary developing device having the above structure will be explained. Now, the first
When power is applied to the driving shaft 40, the gears 41, 3
9, the rotating body 30 is rotationally driven in the direction of the arrow in FIG. At this time, the developing devices (33b to 33c in the illustrated example) that do not contribute to development enter the outer casing 29,
The scrapers 37b to 37c of these developing devices are pushed by the inner wall of the outer casing so that their tips end at the developing rollers 34b to 37c.
34c to prevent leakage and mixing of toner in the developer storage chambers, that is, the partitioned chambers 33b to 33c.

On the other hand, when the developing roller moves inside the outer casing after development, the toner that had adhered to the surface of the developing roller adheres to the inner wall surface of the outer casing. The toner that has adhered to the wall surface will adhere to the developing roller of each developing device. However, the gear 42a of the developing roller shaft of the developing device (33a in the illustrated example) immediately before moving to the developing position (the position closest to the photoreceptor 10) meshes with the internal gear 46,
Due to the rotation of the rotating body 30, the developing roller 34a is rotated by at least an angle α in the counterclockwise direction indicated by the arrow;
The mixed color toner adhering to the developing roller is scraped off by the scraper 37a that is in pressure contact with the developing roller. The scraped off toner 49 naturally falls into a toner reservoir 29a formed in the outer casing 29.

Then, when the developing roller 34a of the developing device 33a reaches a predetermined developing position as shown in FIG. The rotating body 30 is stopped by stopping the power. At this time, the gear 42a of the developing roller shaft is disengaged from the internal gear 46 and meshes with the gear 44 of the second driving shaft 43, and the scraper 37
a is released from the inner wall of the outer casing and restores its elastic restoring force, creating a gap between its tip and the developing roller 34a.

Therefore, when power is applied to the second driving shaft 43 via the chain 50 and sprocket 51, the gear 4
4 and 42a, the developing roller 34a rotates in the direction of the arrow in FIG.
A is regulated into a uniform thin layer by a blade 36a, and is transported to a position facing the photoreceptor 10 for development. This development may be either contact development in which a developing roller is brought into contact with the photoreceptor, or jumping development in which toner is caused to fly into the gap formed between the two. During development, the toner remaining on the surface of the developing roller returns into the developing device 33a through the gap g.

When the development by the developing unit 33a is completed, power is again applied to the first driving shaft 40 to rotate the rotating body 30, and the next developing unit 33b is operated in the same manner as described above.
The control means sequentially controls the image forming apparatus so that the image forming apparatus is moved to the developing position and development is performed.

If there is a risk that the scraper may damage the surface of the photoreceptor 10 when the rotating body 30 rotates, the diameter of both ends of the photoreceptor 10 is slightly larger than the diameter of the photoreceptor in the jumping developing device, as shown in FIG. If the large diameter portions 10a are brought into contact with the developing roller, the large diameter portions can press both ends of the scraper to prevent the scraper from coming into contact with the latent image holder.

As described above, in this embodiment, a rotary body in which a plurality of developing devices are provided at approximately equal intervals on the circumference is rotatably provided in an outer casing having a developing port in the longitudinal direction, and the developing device other than the developing device facing the developing port is provided. is located inside the outer casing, and each developing device located inside this outer casing has a structure in which the tip of the scraper comes into contact with the developing roller, so the developing device can be used by loading and unloading the copying machine with the outer casing intact. You can pick it up. Since the toner in each developing device is naturally agitated by the rotation of the rotating body, no special toner agitating mechanism is required. It is possible to prevent toner from leaking or mixing in each developing device within the outer casing. In addition, the developing roller of the developing device moves to a position facing the developing port,
Just before it reaches the development position, it is rotated by a predetermined angle, and the toner adhering to its surface is scraped off by a scraper, so development by mixed toner can be reliably prevented and clear images with good reproducibility can be produced. Effects such as being able to provide services can be obtained.
Here, developer storage chambers, that is, partition chambers 33b and 33c.
The developer capacity of 33a is the same, and the developer capacity of 33a is approximately twice that of these. In this embodiment, 33a is a black developer, 33b is a sepia color developer, and 33c is a blue developer. The drug was injected.

As explained above, according to the present invention, the interior of the rotating body is partitioned into a plurality of developer storage chambers, and the developer storage capacity of the developer storage chamber that stores frequently used black developer is divided into other developer storage chambers. Since the developer storage chamber is larger than that of the developer storage chamber that stores color developers, it reduces the number of times the frequently used black developer is replenished, making it more convenient for users to use, and reducing the frequency of use. This eliminates coagulation of a small amount of developer and makes it possible to effectively utilize the space within the image forming apparatus.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing an overview of a color copying machine to which the developing device of the present invention is applied, Fig. 2 is an external perspective view of the developing device of the present invention, Fig. 3 is an end view thereof, and Fig. 4 is the figure 2. FIGS. 5 and 6 are cross-sectional views of the developing device for explaining the selection operation of the developing device. 1... Copying machine, 14... Rotary developing device (developing device), 33a, 33b, 33c... Partition chamber (developer storage section), 34a, 34b, 34c... Developing roller (developing means).

Claims (1)

[Scope of utility model registration request] A rotating body, a partition means for partitioning the inside of the rotating body into a plurality of developer storage chambers each storing a different color of developer, and a partitioning means provided in each developer storage chamber for carrying and transporting the developer. and a driving means for rotating the rotating body to move a developer storage chamber storing a developer of a desired color to a developing position. , an image forming apparatus characterized in that the capacity of a developer storage chamber for storing black developer is larger than the capacity of a developer storage chamber for storing developers of other colors; Device.