JPH0679177B2 - Multicolor recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In a multicolor recording apparatus using a plurality of photoconductors, a plurality of dot images of different colors formed on the respective photoconductors are formed so as to at least partially overlap each other on a recording paper. , Multi-color recording with high resolution is performed.

[Industrial application field]

The present invention relates to a multicolor recording method using an electrophotographic process, and more particularly to a multicolor recording method capable of performing high speed, high resolution multicolor recording.

[Conventional technology and problems]

FIG. 4 shows a conventional multicolor recording apparatus using an electrophotographic process. FIG. 5 shows the potential on the photoconductor in the multicolor recording apparatus.

First, the photoconductor is uniformly charged by the initial charger. Then, perform the first exposure with a laser etc.
Attenuate to OV to form the first latent image. Then, development is performed with a first developer using a first color (yellow) toner to form a dot image with a yellow toner on the photoconductor.

The potential of the toner image after the first development is low as shown in FIG. 5 (2). Therefore, recharging is performed next to make the potential on the photoconductor uniform. This is the first
This is to prevent the occurrence of color mixture due to the different color toner used after the second development adhering to the toner image portion having a low potential after the development. After recharging, as in the case of the first exposure, the second exposure is performed with a laser or the like to attenuate the potential of the exposed portion to about OV to form a second latent image. Then, development is performed with a second developer using a second color (magenta) toner to form a dot image with the magenta toner on the photoconductor. As a result, yellow and magenta dot images are formed on the photoconductor.

The potential on the photoconductor after the second development is the second as shown in FIG.
The potential of the toner image area is low. In order to prevent the different color toner from adhering to the low potential portion, recharging is performed to make the potential on the photoconductor uniform. After that, as in the case of forming the first and second toner images, the third exposure is performed by the laser to form the third latent image, and the third latent image is formed by the cyan toner.
Development is performed to form yellow, magenta, and cyan dot images on the photoconductor. After that, the photoreceptor is recharged to make the potential uniform and then subjected to a fourth exposure with a laser to form a fourth latent image, and a fourth development is performed with black toner. By the above process, yellow,
A magenta, cyan, and black dot image is formed on the photoconductor to obtain a multicolor toner image. These toner images are collectively transferred to the recording paper, and heat fixing is performed to obtain a permanent multicolor image on the recording paper. The photoconductor is then repeatedly used by cleaning the residual toner and removing the charge.

In such a recording method, the dot arrangement is such that yellow, magenta, cyan and black are arranged in parallel as shown in FIG.
Multicolor recording is performed with this as one pixel. If the size (d) of one dot is about 100 μm, one pixel is 4d, that is, 400
μm, and the resolution is 2.5 lines / mm. In such a conventional method, high-speed recording is possible because multicolor recording is performed during one rotation of the photosensitive drum. However, 4 around the photosensitive drum
An image forming process corresponding to one color must be provided, and the device becomes large-scale. The resolution is also low at 2.5 lines / mm.

FIG. 7 shows the structure of a multicolor recording apparatus proposed by the present inventors in Japanese Patent Application No. 60-16051. Unlike the conventional method shown in FIG. 4, two photoconductors are used. Yellow and magenta dot images are formed on the photoconductor (1) and transferred to a recording paper. On the photoconductor (2), cyan and black dot images are formed and transferred onto the recording paper on which the yellow and magenta dot images have been transferred to perform multicolor recording. In this recording method, since a dot image is formed for each of the two colors on each photosensitive drum, the apparatus does not become large-scale unlike the conventional method shown in FIG. However, the dot arrangement is as shown in FIG.
The dot image on the photoconductor (1) and the dot image on the photoconductor (2) were arranged in parallel on the recording paper.

Therefore, if the size (d) of 1 dot is 100 μm, then 1 pixel is 4d, that is, 400 μm, and the resolution is 2.5 lines / mm.
Is. As described below, the method using the apparatus shown in FIGS. 4 and 7 is capable of high-speed recording but has low resolution.

An object of the present invention is to provide a multi-color recording method having a high resolution by arranging dot images forming one pixel so that at least some of them overlap each other.

[Means for solving problems]

According to the present invention, a plurality of photoconductors are arranged in parallel, and a plurality of charging means, a plurality of latent image forming means, and a plurality of developing means including toners of different colors are provided around the respective photoconductors. Are provided to form dot images of different color toners on the respective photoconductors, and then the dot images on the respective photoconductors are sequentially transferred to a recording sheet to perform multicolor recording. The multi-color recording method is characterized in that the multi-color recording method is formed in a continuously connected state on each of the photoconductors so that they at least partially overlap each other on the recording paper.

[Work]

That is, according to the present invention, a plurality of photoconductors are used to form dot images of different color toners on the respective photoconductors, and then the dot images are sequentially transferred to a recording paper in a continuous state and recorded. Overlay at least a portion of the dot images on the paper.

According to this method, the number of dots included in one pixel increases.
That is, each dye becomes dense and a high resolution is obtained.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. An embodiment of the present invention in the case of using the multicolor recording apparatus of FIG. 7 using two photoconductors will be described below.

The dot images of yellow and magenta are formed on the photoconductor (1), and the dot images of cyan and black are formed on the photoconductor (2), which is the same as the conventional example, but the photoconductors (1) and (2) are formed. The method of arranging the dot images above is different. As shown in FIG. 1, on the photoconductor (1), the yellow and magenta dot images are arranged side by side, and on the photoconductor (2), the cyan and black dot images are arranged side by side. To array. Further, the dot images on the respective photoconductors are so arranged that their centers are displaced by d / 2. The dot image formed by the yellow and magenta toners formed on the photoconductor (1) is transferred to the recording paper,
Next, the dot images formed by the cyan and black toners on the photoconductor (2) are also transferred onto the recording paper on which the yellow and magenta dot images have been transferred. At this time, since the centers of the dot images on the photoconductors (1) and (2) are shifted by d / 2, the dot images overlap on the recording paper and one pixel becomes 2d as shown in FIG. If the diameter of one dot is 100 μm, one pixel is 200 μm, that is, the resolution is 5 lines / mm,
It is twice the conventional method.

In the present invention, since the dot images on the respective photoconductors are transferred so as to at least partially overlap each other on the recording paper, the size of one pixel becomes small and high resolution recording becomes possible.

In the above-mentioned embodiment, the case where two color dot images are formed on each of the two photoconductors has been described. However, even when three or more photoconductors are used, the present invention can be applied. It goes without saying that high resolution recording is possible.

Further, according to the present invention, as shown in FIG. 2, the dot image on the photoconductor (1) is shifted by d /
It does not have to be 2 and can be larger or smaller than d / 2.

Further, as shown in FIG. 3, if one part is made to overlap also in the vertical direction of the dot, one pixel becomes smaller, and higher resolution recording can be obtained.

〔The invention's effect〕

As described above, according to the present invention, since the dot images overlap on the recording paper, the size of one pixel can be reduced,
High resolution multicolor recording can be performed.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a dot arrangement in the present invention obtained by using the device B, FIG. 2 is a schematic diagram showing another dot arrangement in the present invention, and FIG. 3 is still another in the present invention. FIG. 4 is a schematic diagram showing a dot array of FIG. 4, FIG. 4 is a schematic diagram of a conventional multicolor recording device A, FIG. 5 is a schematic diagram showing potential on a photoconductor, and FIG. 7 is a schematic view showing a dot arrangement in FIG. 7, FIG. 7 is a schematic view of a multicolor recording apparatus B proposed by the present inventors, and FIG. 8 is a schematic view showing a dot arrangement of the apparatus B.

Front page continuation (72) Inventor Junzo Nakajima 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited (56) References JP-A-58-211169 (JP, A) JP-A-57-167034 (JP, A)

Claims (1)

[Claims] 1. A plurality of photoconductors are arranged in parallel, and a plurality of charging means, a plurality of latent image forming means, and a plurality of developing means containing toners of different colors are provided around each of the plurality of photoconductors. In the multicolor recording method for performing multicolor recording, after forming dot images of a plurality of toners of different colors on the respective photoconductors, the dot images on the respective photoconductors are sequentially transferred to a recording paper to perform multicolor recording. A multicolor recording method, wherein images are continuously formed on the respective photoconductors so that the images at least partially overlap each other on the recording paper.