JPH0336228B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color electronic copying apparatus with improved color balance.

As a conventional color electronic copying device, for example, there is one shown in FIG. 1, which includes a platen 2 on which a document 1 is placed, a console having a start key (not shown), a copy number display section (not shown), etc. 3 is provided on the top of the copying machine 4. Inside the copying machine 4, there is a scanning system 5 (light source lamp 5) that scans the original 1.
a, mirrors 5b, 5c, 5d, lens mirror 5
e, a color filter 5f), a photosensitive drum 6 exposed by the scanning system 5, a transfer drum 7 that contacts the photosensitive drum 6 at a transfer section 6a, a paper feed tray 8a that supplies copy paper to the transfer section 6a, 8b is provided. Around the photosensitive drum 6, a charging corotron 9, an exposure slit 10, and a photosensitive drum 6 are arranged.
an inter-image lamp 11 that erases the charge in the non-image area of the photosensitive drum 6;
f is green, blue, red filter 51,
52, 53, and corresponding to these three colors, magenta,
Yellow and cyan developing sections 13a, 13b, 13
c), a transfer corotron 14 provided in the transfer unit 6a, a cleaner 15 for removing the toner after transfer from the photosensitive drum 6 (the toner removed by the brush 15a is sucked by the fan 15b), and the photosensitive drum 6. Erase lamp 16 for erasing the residual potential of
is provided. A transport belt 17 and a fixing section 18 are provided downstream of the transfer section 6a, and a microcomputer 1 that controls the operation of the copying machine 4 is provided.
9 is provided. The microcomputer 19 has an input interface 19a that inputs sensor signals or operation command signals from various sensors in the copying machine 4 or the console 3, and a ROM 19b that stores programs necessary for arithmetic processing of input signals. a CPU 19c that performs predetermined calculations;
RAM1 that temporarily stores calculation results, data, etc.
9d, and an output interface 19e for outputting control signals to various control objects of the copying machine 4 or to the display section of the console 3 based on calculation results.

To explain the operation in the above configuration,
After placing the original 1 on the platen 2, when a print command is issued from the console 3, the scanning system 5 scans the original 1 and forms a latent image on the photosensitive drum 6. The photosensitive drum 6 on which the latent image has been formed is charged with non-image areas by an interimaging unit 11. The document scanning described above is performed three times according to the operation of the green, blue, and red filters of the color filter 5f (FIG. 2 shows the three-color filter 51,
It shows the spectral transmission characteristics of 52 and 53, B is blue,
G is green, R is red), developing sections 13 corresponding to each latent image (13a... magenta, 13b...
Yellow, 13c...cyan) are developed, and transfer corresponding to the three colors is performed on the copy paper held by the transfer roll 7 in the transfer section 6a. The copy paper receives three color transfers and transfers to the transport belt 17.
After being fixed in the fixing section 17, it is discharged.
Each of the above operations is controlled by the microcomputer 19.

However, according to the conventional color electronic copying device,
When an original is scanned, the blue part of the original has a lower reflectance than the red part of the original, so the spectral reflectance of cyan toner C and magenta toner M (Figure 3), which reproduces a blue image, is 600~600 for magenta toner M.
Since the reflectance of cyan toner C in the 400 to 500 mμ (blue region) is lower than the reflectance in the 700 mμ (red region), the blue part of the copy image becomes darker than the red part of the image, resulting in poor color balance. (Actually, since yellow toner Y is slightly added to cyan toner C and magenta toner M, the above-mentioned tendency becomes a little stronger.)

The present invention has been made in view of the above,
In order to reduce the darkness of the blue part of the copy image and improve the color balance, spectral exposure adjustment has an exposure adjustment means having an ND filter or a slit with a variable width, and a spectral exposure means having a cyan or blue filter. At the time of spectral exposure using a green filter, spectral exposure using a cyan or blue filter of the spectral exposure means is used based on the exposure degree according to the magenta component in the cyan toner, and spectral exposure using the cyan or blue filter is performed. The present invention provides a color electronic copying apparatus in which the amount of magenta toner adhered is controlled by controlling the amount of exposure using an exposure amount adjusting means.

The color electronic copying apparatus according to the present invention will be explained in detail below.

Figures 4A and 4B show an embodiment of the present invention;
The same parts as in the figure are indicated by the same reference numerals, so repeated explanations will be omitted, but the color filter 5f has a green filter 51, a blue filter 52, and a red filter 53. As shown, it has a green filter section 51a and a cyan filter section 51b,
The cyan filter section 51b includes an ND filter 51c (Neutral Density Filter) that adjusts the amount of light.

In the above configuration, in the same way as in the operation shown in FIG.
When spectral exposure was performed in step 2, it was developed with yellow toner,
A color image is obtained by performing spectral exposure using a red filter 53 and developing with cyan toner.
In this process, the green filter section 51a of the green filter 51 passes the green component of the scanning light of the original 1, and the cyan filter section 51b
passes the cyan component of the amount of light adjusted by the ND filter 51c (the amount of light is adjusted so that adhesion of magenta toner is reduced by an amount corresponding to the amount of magenta in the cyan toner). green filter 5
The green component and cyan component that have passed through the photosensitive drum 6 reduce the potential of the exposed portion of the photosensitive drum 6 to form a latent image, and the developing section 13a attaches magenta toner according to the potential of the latent image. This operation controls the adhesion amount of the magenta toner in the cyan toner and magenta toner that reproduces the blue image, so
The blueness of the blue part can be reduced.

FIG. 4C shows an embodiment in addition to the green filter 51, which includes a green filter section 51a, a cyan filter section 51b, and a shutter 51d for controlling the width x of the optical path of the cyan filter section 51b.
By controlling the width x according to the amount of magenta in the cyan toner, the amount of magenta toner attached can be controlled.

FIG. 4D shows still another embodiment of the green filter 51, which has a transmittance of 400 to 500 mμ corresponding to the magenta component in the cyan toner, and a transmittance of 500 to 600 mμ that corresponds to the normal transmittance. By arranging the green filter 51, the same operation as in the previous embodiment can be performed.

In the above embodiments, the amount of adhesion of magenta toner is controlled by the cyan filter at the same time as the exposure scan is performed by the green filter.
It may be done before or after that. Also, a blue filter can be used instead of the cyan filter.

As explained above, according to the color electronic copying apparatus according to the present invention, the spectral exposure adjustment means includes the exposure adjustment means having an ND filter or a slit with a variable width, and the spectral exposure means having a cyan or blue filter. At the time of spectral exposure using a green filter, spectral exposure using a cyan or blue filter of the spectral exposure means is also used based on the exposure level according to the magenta component in the cyan toner, and the spectral exposure amount using the cyan or blue filter is Since the adhesion amount of magenta toner is controlled by controlling the amount of magenta toner by the exposure adjustment means, it is possible to reduce the darkness of the blue portion of the copy image and improve the color balance.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a conventional color electronic copying apparatus. FIG. 2 is an explanatory diagram of the spectral transmission characteristics of a color filter. FIG. 3 is an explanatory diagram showing the reflectance of color toner. FIG. 4A is an explanatory diagram showing one embodiment of the present invention.
FIGS. 4B, 4C, and 4D are explanatory diagrams showing three configuration examples of the green filter in FIG. 4A. Explanation of symbols, 1... Original, 2... Platen, 3
...Console, 4...Main body, 5...Scanning system, 6
...Photosensitive drum, 7...Transfer drum, 8a, 8b
... Paper feed tray, 9 ... Charging section, 10 ... Exposure section, 11 ... Interimage lamp, 13 ...
Developing section, 14... Transfer section, 15... Cleaning section, 16
... Erase lamp, 17 ... Transport belt, 18 ... Fixing section, 19 ... Microcomputer, 51
... Green filter, 52 ... Blue filter, 53 ... Red filter, 51a ... Green filter section, 51b ... Cyan filter section, 5
1c...ND filter, 51d...shutter.

Claims (1)

[Scope of Claims] 1. A color filter that exposes a photoconductor to spectral light by scanning a color original, a developing section that develops a latent image with color toner corresponding to the spectral exposure, and a fixing unit after transferring the developed image to copy paper. The copying apparatus has a spectral exposure adjustment means having an exposure adjustment means having an ND filter or a slit with a variable width, and a spectral exposure means having a cyan or blue filter, wherein the color filter is At the time of spectral exposure using a green filter, spectral exposure using a cyan or blue filter of the spectral exposure means is also used based on the exposure degree corresponding to the magenta component in the cyan toner, and the spectral exposure amount using the cyan or blue filter is adjusted. A color electronic copying apparatus characterized in that the amount of magenta toner deposited is controlled by the exposure amount adjusting means.