JPS62296669A - Digital color copying machine - Google Patents

Abstract

PURPOSE:To always obtain a color image with excellent reproducibility by color printing the patch of transfer paper with plural colors, reading and storing a spectral reflection density, and color mask processing a color image reading information by using the spectral reflection density. CONSTITUTION:An original is set on a platen, scanned, and read. Color image information are obtained from sensors 43-45, amplified 46, A/D-converted 47, and inputted to an arithmetic unit 50. The arithmetic unit 50 color-mask- processes the image information by using a correction information from a RAM 49, and executes other processings, then transfer the information to a laser writing device 17 in order to print it in color 2. A control part 51 controls the A/D converter 47, a ROM 48, the RAM 49, and the arithmetic unit 50. With such constitution, a color-corrected copy 5 is obtained by printing in yellow Y, mazenta M, cyan C, and black BK separately, can be obtained, or even by varying the density. By such method, the image of excellent color reproducibility can be always obtained without any influence due to the changing of transfer paper, deterioration irrespective of the mixing of colors and a light source, or the displacement of the level of read signals.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a digital color copying machine having an image sensor and a color printer.

(Prior art) In conventional digital color copying machines, color reproducibility is processed only by coloring materials such as toner and ink, gamma characteristics for writing color image data, and color separation characteristics for reading color images, and the processing is also performed using a certain transfer paper. It was limited to those against For this reason, color reproducibility deteriorated depending on the transfer paper. In addition, the color reproducibility tended to change with use due to color mixture deterioration of "Color 1" and changes in the color image reading level due to deterioration of the light source.

(Objective) It is an object of the present invention to provide a digital color copying machine that eliminates the above-mentioned drawbacks and can always produce color images with good color reproducibility.

(Structure) The present invention is a digital color copying machine that reads a document with an image sensor and outputs it with a color printer.The color printer prints patches of multiple colors and transfer paper, and the spectral reflection density of this print is read by the image sensor. and means for performing color masking processing on the color image read data from the image sensor using the spectral reflection density data in the storage means.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the invention.

This embodiment is printed by a color scanner 1, a color printer 2 consisting of a laser printer, a print feedback device 3, and an ADF (automatic document feeder) 4.

In the color correction mode, the color printer 2 outputs a print 5 as shown in FIG. This print 5 is a mixture of patches 6 to 9 printed with yellow (Y), magenta (M), cyan (C), and black (Bk), Y and M and C2, Y and M, M and C, and C and Y. It includes patches 10 to 13 printed with the respective colors, and patch 14 printed with the background portion of the transfer paper. In this case, in the color printer 2, the photosensitive drum 15 is rotated by the drive section and uniformly charged by the charger 16, and then the laser writing device 1
7, each color component of a color image, that is, data of red, blue, green, and black, is written every rotation to form a latent image, and each latent image is processed by color developing devices 18 to 21 into Y, Y, and black data.
M.

Each of C and Bk is developed every rotation by a toner, and transferred to a transfer paper on a transfer drum 22 in an overlapping manner by a transfer device 23, and then cleaned by a cleaning brush 53. Further, the transfer paper is fed from the paper feeder 24 and wound around the transfer drum 22, and transferred to the photoreceptor drum 15 by the transfer device 23.
Four color images are superimposed and transferred, and the static electricity is removed by a static eliminator 25 to form a color image. After the color image is formed on this transfer paper, it is separated from the transfer drum 22 by a separating claw 26, the color image is fixed by a fixing device 27, and the paper is sent out. Here, data is input to the laser writing device 17 from a read-only memory (ROM) so that print 5 can be obtained, and the transfer paper sent out from the fixing device 27 becomes print 5. The print feedback device 3 is in the color correction mode, and the branch claw 28 is lowered, and the print 5 from the fixing device 27 is transferred to the conveyance rollers 29 to 31, the conveyance guides 32 to 35, and the ADF 4 in the print feedback device 3.
The document is conveyed to the document table 36'' of the color scanner 1. In the color scanner 1, the light source 37 illuminates the print 5 on the document table 36, and the reflected light is reflected from the mirrors 38 to 40.
The print 5 is separated into three colors by a lens 41 and a dichroic prism 42 for three-color separation, and images are formed on image sensors 43 to 45.The print 5 is scanned by the movement of the light source 37 and mirrors 38 to 40, and the spectral spectrum of the print 5 is generated. The reflection density is read. The data from the image sensors 43 to 45 is converted into a digital signal by an analog/digital converter 47 via an amplifier section 46 as shown in FIG.
Enter M48. In the ROM 48, data corresponding to the input digital signal is read from the pre-stored reference spectral reflection density as correction data for each patch 6 to 14, and is stored in a random access memory (RAM) 49.

In the original copy mode, an original is set on the original platen 36'' by the ADF 4 or manually and read by the color scanner 1, and the color image data from the image sensors 43 to 45 is sent to the amplifier 46 and the analog/digital converter 47. and is input to the calculation unit 50. The calculation unit 50 performs color masking processing and other processing on the input color image data using the color correction data in the RAM' 49.
It is sent to the laser writing device 17 and printed on the color printer 2. In this case, the branching claw 28 of the print feedback device 3 is raised upward, and the print sent out from the fixing device 27 is discharged onto the paper discharge table 52. Also, the control section 51
is an analog/digital converter 47. ROM 48.
RAM, 49. Controls the calculation unit 50.

In the above embodiment, patches 6 to 4 as shown in FIG. 2 were used, but the density level etc. may be changed.

Further, the print 5 may be accurately placed at the original reading position without using the print feed device 3 and the ADF 4, and color correction can be performed accurately by performing the color correction mode and the original copy mode.

Also, in Figure 4, (A) is an example of the spectral reflectance of the transfer paper used, (B) is the spectral reflectance of the ideal transfer paper, and (C) is the spectral reflectance of the ideal transfer paper.
is an example of the spectral reflectance of the original, (D) is the spectral reflectance of a color image of the original (C) printed on the transfer paper of (A) without masking processing, and ('E) is the spectral reflectance of a color image of the original printed with masking processing. This is the spectral reflectance of an object printed in the same manner as (D). The transfer paper in this example (A) is a slightly yellow paper, and (C)
The original color is close to blue-green. In this case, without masking, the transfer paper in (A) will be close to yellow, so (D)
If the original is printed 1~, the color will be close to green. On the other hand, in the printed product (E) which has been subjected to the masking process, the yellow coloring material is reduced and a spectral reflectance visually close to that of (A) can be obtained.

(Effects) As described above, according to the present invention, in a digital color copying machine that reads a document with an image sensor and outputs it with a color printer, it is possible to print a plurality of colors and patches on the background of the transfer paper with the color printer, and then print this print. means for causing the bipedal image sensor to read the spectral reflection density and storing it in the storage means; and means for performing color masking processing on the color document read data from the image sensor using the spectral reflection density in the storage means. With this arrangement, it is possible to always obtain a color image with good color development regardless of changes in the color image reading level due to color mixture deterioration of different transfer papers or color materials or deterioration of the light source.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a plan view showing a color correction print of the same embodiment, FIG. 3 is a block diagram showing the circuit section of the same embodiment, and FIG. 4 FIG. 2 is a diagram for explaining the same embodiment. 1...Color scanner, 2...Color printer, 48...ROM, 50...Calculating unit. Namaki (mm) Ushika+8) (D) Koki (mrn)

Claims (1)

[Claims] In a digital color copying machine that reads a document with an image sensor and outputs it with a color printer, the color printer prints a patch of multiple colors and the background part of the transfer paper, and the image sensor reads the spectral reflection density of this print. A digital color copying machine, comprising means for storing data in a storage means, and means for performing color masking processing on color document read data from the image sensor using spectral reflection density data in the storage means.