JPS58150974A - Image forming device - Google Patents

Abstract

PURPOSE:To perform image formation free of disorder of picture quality and color mixture, by making the gap between an image carrier surface and a preceding developing device greater than that between the image carrier surface and a succeeding developing device. CONSTITUTION:As a photosensitive drum 1 rotates, its surface is irradiated with information irradiation lights L1, L2, and L3 successively. In this case, a developing device 3 supplies a magenta color developer to the drum 1, a developing device 5 supplies a cian color developer, and a developing device 7 supplies a yellow color developer; and latent images corresponding to respective optical images are developed and the full-color developed image formed on the drum 1 is transferred to a transfer material P. Then, the gap d between the developer layer 71 of the developing device 7 and the drum surface is made greater than the gap d2 of the developing device 5 to obtain a multicolored picture free of color mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus, and the detailed VC relates to an image forming apparatus that sequentially forms four different color developments on an image carrier.

Conventionally, scratch resistance corresponding to different color component images is formed on an image carrier such as a Kameko photographic photoreceptor as foil images with mutually different charge polarities, or even if the charge polarities are in the opposite direction, mutually different surfaces are formed. A method is to form a full latent image of the image, and then develop these images sequentially with a corresponding color developer to form two color peaks.Alternatively, the image carrier is irradiated with light according to different color component images. Fully form the image on top, increase the potential of the corresponding scratch resistance before developing each color, and then develop the corresponding color to complete the color image? Methods for forming such a structure have been proposed.

In all of these methods, it is common that different color developments τ are performed sequentially on the same image carrier.

In an image forming apparatus of this type, developing a foil image requires the following steps:
Generally, magnetic brush development is used.

However, in such an apparatus, there is a risk that the previously formed images may be disturbed during subsequent development, and color mixing is also difficult to avoid.

The present invention has been made in view of the above points.

Good image formation without image quality disturbance and color mixture? The present invention relates to an image forming apparatus that enables image forming. Furthermore, a misfire? The present invention relates to a device that prevents the occurrence of color mixing even after long-term use.

The present invention provides an image forming apparatus that sequentially forms different color developments on an image carrier, in which the entire gap between the developer layer and the surface of the image carrier is maintained, and the image on the surface of the image carrier is Accordingly, the developing means is provided with a number of nuclei that selectively avoid the developer meeting as a flying shield to the above-mentioned table. Let *m be the width of .

Hereinafter, details of the present invention will be explained by way of specific examples and with reference to the drawings.

Bu1 FIG. 1 shows a specific example image forming apparatus based on the present invention. A schematic diagram of Rir.

Reference numeral 1 designates a photoreceptor drum, and reference numeral 02, which rotates in the direction of the arrow, represents a corona discharger, which uniformly radiates the surface of the photoreceptor drum to a predetermined polarity.

L is the first information illumination light, which produces, for example, a full, color original green component light image. This light image may be a light beam modulated by a laser beam, light emitted from an LED element, or a normal optical image.

Reference numeral 3 denotes a first developing device, for example, a magenta color developer is applied to a full photosensitive drum 1, and a visual image method for converting a young image into a purple color according to the light image is a well-known magnetic brush developing method. However, in the illustrated example, the jumping developing method will be described in detail later.

4 is the second corona discharger, and the corona discharger 62
Corona discharge of the same polarity as the original body drum 1 Ryuko. L
2 is the second information illumination light, which is, for example, the original red component light source.

Reference numeral 5 denotes a second developing device, which supplies a cyan developer, for example, and develops a positive image corresponding to the second optical image. The development method is so-called jumping development, in which the developer layer is kept facing the photoreceptor drum tiUkJv at regular intervals, and the developer is splashed onto the ketolum surface in response to the positive image on the drum's next surface. The specific structure VC of the developing means will be described in detail later.

Reference numeral 6 denotes a third corona discharger which applies corona discharge of the same polarity as the aforementioned corona discharger to the surface of the photoreceptor drum.

L3 is the third information irradiation light, for example, the original growth spectral image.

7 is the third developing device, for example yellow color developer? !
: The image is revealed according to the third light image. The developing method is a jumping developing method similar to the second developing method. However, as will be described in detail later, the distance between the developer agent 1@ and the next surface of the photoreceptor drum is made wider than in the case of the second developing means. The image is transferred onto the transfer material P by the action of the transfer corona release device 8.

The transfer material P after the transfer length r is separated by a separation roller 9 and fixed by a fixing means (not shown).

On the other hand, after the transfer is completed, the surface of the photosensitive drum 1 is cleaned of residual developer by the cleaning means 10 and is ready for reuse.

With the above-mentioned configuration device, good multi-color lI without color mixture! lI
You can get the image.

The mechanism for preventing color mixture in the above-mentioned device will now be explained in detail.

FIG. 2 is a side view of a jumping developing device used as a developing device of an embodiment of the present invention.

The non-Ijii body sleeve 31 is rotatably supported,
It rotates in the direction of the arrow, driven by a drive source (not shown).

A six-pole magnet roller 32 is fixed inside the non-magnetic sleeve 31 . The inside of the magnetized pole of the magnet roller contributes to regulation when forming a developer layer on the sleeve surface. Further, S contributes to the development action on the surface of the photoreceptor drum. The other magnetic poles serve to transport the developer and prevent it from leaking.

33 is a developer layer thickness regulating blade made of a magnetic material. It works together with the abrasive pole plate to form a magnetic field that crosses the direction of movement of the sleeve 31, thereby regulating the total thickness of the developer layer adhering to the sleeve 31. The thickness of the comparison agent layer is 30μ or more and about 100μ
The gap between the surface of the non-magnetic sleeve and the photosensitive drum is maintained at 250 to 3 LIOμ so that the developer layer on the sleeve surface does not come into direct contact with each other. The developer particles selectively fly to the latent image area due to the electric field formed between the large image group on the photosensitive drum and the non-magnetic sleeve. The magnetic pole SI placed at this development position prevents unnecessary movement of the developer. On the other hand, the magnetic field strength gradually decreases from the sleeve surface toward the photoreceptor drum to assist in directing the flying developer particles toward the photoreceptor drum. 34 is a bias power supply that applies an alternating voltage of a predetermined frequency to the sleeve surface. The structure is such that a DC bias voltage is applied depending on whether the voltage is 0 or 0. By applying this alternating voltage, selective flying of the developer can be easily and reliably carried out.

Reference numeral 35 denotes a pressing blade that completely prevents the developer in the housing from solidifying into particles.

With the above configuration, the latent image (il-developed) on the photoreceptor is converted into a single image.

By the way, it is necessary to mix a magnetic material such as magneta' I) into the strong developer, and since this is black or reddish brown,
The reality is that it is difficult to obtain a color-containing color-determining agent for colors other than black, red, or magenta. Therefore, it is recommended to use a non-neutral dust source as a color-determining agent for colors such as yellow and cyan. Necessary for good color reproduction 〇The D1 image forming apparatus of the present invention uses a developing scissors tray with jumping development KMJ function that uses non-magnetic developer for color development. .

Figure 3 shows jumping development using non-imaging developer? FIG. 2 is a side view of a specific example developing device.

51C The developing roller is made of an aluminum ram (or a conductive member such as stainless steel). 52 is a developer layer thickness regulating plate V-
The layer thickness is approximately 30 μm or more and approximately 00 μm as described above. 53 is a bias power supply 0 54 is yl, source drug delivery risk 17. - to develop the developer.
During the feeding operation, the developer is fed to the main roller and the developer is accelerated. Each feed scree = 54, , 542
．． 54. may be rotated at a constant speed, but it is also possible to improve the # effect by varying the rotation speed such as high speed - low speed - high speed.

It is selected by taking into account the relationship τ of the 甐悌 fluoroden series to the 9th grade IJ and the present condition. As expected, ψ1j is made of stainless steel.

Jumping of non-imaging developer in the above-described developing device 91
The third image representation of the non-equipment in Figure 1, in which the image is a town, also uses the above-mentioned constituent devices. or may be unified to the non-magnetic force type shown in the third figure. Father, each person may do as they wish independently. When color sensitivity is required, a non-magnetic method is better. - From the viewpoint of power and simplicity, a cicada developer method is better.

By using a non-contact developing device tray like the above-mentioned jumping method that selectively splashes the developer onto the purple l\r image area, disturbances and color mixing in the multicolor image formed on the photoreceptor can be effectively prevented. In addition, the illustrated example #C shows a photoreceptor as a special image carrier, but it can also be used as a simple insulating image carrier in the case of an image transfer method or a static electricity distribution method of an electrode pin array. Also good.

By the way, I am very proud of the non-contact type developing device.
The inventors of the present invention have discovered that when unfinished and used for a long period of time, color mixing may occur in the developing device placed on the rear side.

If this phenomenon occurs, the developer in the developing device must still be replaced, and an inconvenient noise is generated that requires frequent maintenance and inspection.

In the apparatus of the present invention, as a countermeasure against the above, the non-contact developing device #
? When arranging them sequentially, the gap d (1, 2, 3) between the developing device (only the developing sleeve rollers 31, 51, and 71 are shown) and the image carrier surface is set as shown in the fourth figure, compared to the case of the first developing device. Others are set widely.

That is, when the gap between the first developing device and the image carrier is d+'r, the gap between the second developing device and the image carrier is dzkdl<
d2, and the third g1. The gap d between the image device and the image carrier also has a relationship such that d+ < tis.

Also, if necessary, the second developing device and the third developing device are =dt=
Although ds is also possible, it is preferable that d2<ds.

The above relationship will be further explained using an example.0 <Example 1> Using the first illustration forming device, the first developing device and the second developing device were operated under the conditions shown in the table below to form a two-color image. I went. or,
Each fN 11 potential was +450■0 Table 1 1st developing device 2nd developing device drum-sleeve gap: d 150μ
150μ bias power supply Do: Vno +1oov
11oov sleeve rotation speed 18Orp
m 180 rpm developer black red Good images were obtained on A4 size transfer material up to about 3000 sheets when two-color images were formed under the above conditions. 3000
When the number of sheets was exceeded, it was found that black developer was mixed into the second developing device. Image quality was also affected.

Next, the drum-sleeve gap d2 of the second developing device is set to 2.
When similar two-color image formation was performed using 00μ and other conditions as shown in Table 1, images of excellent image quality could be formed even after exceeding 3000 sheets〇〇〈Example 2〉 First drawing composition device First, three-color image formation was carried out under the conditions shown in the table below. The Urakami potential was +450v for each.

Table 2 First developing device Second developing device Third developing device Drum/sleeve gap: d 200μ 250μ 250
μ bias source: VDO+100V +100
V +100V sleeve rotation speed 18Orpm
180rpm 180rpm developer black
Blue Red An A4 size transfer material was used in the same manner as in the previous example. Continuous lI! ] Il during image formation! The ll statues are all lI! It was confirmed that there was no Ll image disturbance and that there was no color mixture and that the tip was good. It was found that the blue developer used in the second development was mixed into the third development device, which continuously formed images at 5000 N, and the image quality was also affected.

Next, the Hds between the drum and sleeve of the third developing device is set to 3.
Similar three-color image formation was carried out under conditions of 20μ and other conditions as shown in Table 2. At this time, even if the number of cans exceeds 5,000, it will be 1
There was no adverse effect on the 1i11 purchase.0 As detailed above in the specific examples, the apparatus of the present invention can successfully develop the m-image formed on the same carrier without disturbing the entire image, and can also be used for subsequent development. It is an excellent product that can form a good multicolor image without disturbing the previous development process.

[Brief explanation of the drawing]

1 is a schematic diagram of a specific example image forming apparatus based on the present invention, FIG. 2 is a side view of a specific example developing device used in the present invention, and FIG. 3 is a schematic diagram of a specific example developing device used in the present invention. FIG. 4 is a schematic diagram showing the arrangement of the six developing devices in the apparatus of the present invention. In the figure, 1: Photoreceptor drum (image carrier) , 2,4°6=corona discharger, 3. b, 7: developing device, 8: transfer corona discharger. Applicant: Canon Co., Ltd. 1'-! N (2・i 22nd

Claims (1)

[Claims] (1) In an image forming apparatus that sequentially forms different color developments on an image carrier, a developer layer is made to face the bottom surface of the image carrier with a gap therebetween, and a developer layer is formed to face the bottom surface of the image carrier with a gap therebetween, and the developer layer is formed in accordance with the foil image at the interface of the image carrier. A plurality of developing means for selectively flying the developer onto the surface are all provided, and the gap 7 of the developing means acting later is made wider than the gap between the developing means acting first and the narrow surface of the image carrier. Features of the image forming device.