JPH0243394B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reading device applied to a copying device for copying or duplicating an original document, or an image forming device such as a facsimile machine, and in particular to a reading device that is applied to an image forming device such as a facsimile. The present invention relates to an image reading device that scans and discriminates and reads information carried on the original surface as different color information.

Recently, an image forming apparatus has been proposed that reads the image information of a document in bits and converts it into an electrical signal, and digitally records the image in multiple colors according to the converted signal.One recording method for this is, for example, the inject recording method. .

When attempting to perform multicolor copy recording using the in-jet recording method, images at the same point on a document are separated into colors and read as signals of different spectral wavelengths, which are then recorded using recording heads of colors corresponding to the read signals.
Furthermore, if necessary, a black signal is extracted from the read signal of each color and recorded with black ink.

However, the method of overlaying black ink on chromatic ink has the disadvantage that a large amount of ink is overlaid as black information, resulting in a very blurry image, especially for originals mixed with documents, and there are also areas where black is recorded. Colored ink is wasted. If other chromatic inks are applied to the black information area, it will not be so bad in full color, but if it is a black and red manuscript, it will look extremely unnatural and visually unsightly.

Furthermore, due to differences in the spectral sensitivity of the reading sensor and the slice level during digitization, chromatic colors may be recorded at the edges of black information.

In view of this point, it is an object of the present invention to prevent the boundary portions of black information from being contaminated with chromatic coloring materials.

In order to achieve this object, the image reading device of the present invention includes a color sensor (in the embodiment, a color sensor (line sensor 5, 6), processing means for generating a recording black component signal and a plurality of recording chromatic color component signals from a plurality of color signal components obtained from the color sensor (in the embodiment, a gate 20, a flip-flop 12, a delay circuit), 14), the plurality of color component signals are combined to suppress the generation of chromatic components at the boundary of the recording black component, and the recording chromatic component signal is combined for a period including the vicinity of the boundary. Generating means for generating a prohibition signal that prohibits recording (in the embodiment, a delay circuit 13, an OR gate 17,
(equivalent to ant gate 18 and inverter 19),
The apparatus includes prohibition means (corresponding to AND gates 21 and 22 in the embodiment) for prohibiting the supply of the chromatic color component signal to the color printer while the prohibition signal is generated.

The present invention will be described in detail below based on embodiment examples.

FIG. 1 is a schematic configuration diagram for explaining the configuration of a black, red, and blue three-color copying apparatus, which is one of the preferred embodiments of the present invention. In Figure 1, original 1 is light source 2.
, and its light image is formed on line sensors 5 and 6 by an imaging lens 3. The optical image is split along the optical path by a dichroic mirror 4, with the red color, or long wavelength, being reflected, and the blue color, or short wavelength, being transmitted. Therefore, the sensor 6 detects the brightness of the long wavelength light image, and the sensor 5 detects the brightness and darkness of the short wavelength light image. Sensors 5 and 6 are
It consists of a line-shaped sensor such as a CCD or BBD, but it may also be a sensor that detects a single point on an image such as a photomultiplier or a photodiode. The line information detected by sensors 5 and 6 is sequentially outputted in time series using clock pulses from clock generation circuit 7, and after amplified in amplitude by amplifier circuits 8 and 9, comparators 10 and 11 output the line information based on a certain level. It is binarized into . The long wavelength signal is latched by a D-type flip-flop 12 and input to a delay circuit 13 consisting of a shift register. On the other hand, short wavelength signals are input to the delay circuit 14. The edge of the black information of the document is delayed by the delay circuit 14 so that it starts at the same timing as the output of the flip-flop 12. For example, if the pulse width of a long wavelength image is spread by one bit to the edge of the image compared to a short wavelength image, the short wavelength is transmitted with a one bit delay according to a command from the delay instruction circuit 16. The delay instruction circuit is a switch that selects the output terminal of the delay circuit 14. On the other hand, when the short wavelength signal is delayed by 1 bit, the long wavelength signal is delayed by 2 bits by the delay circuit 13.

Furthermore, a signal with a longer wavelength is formed by logical ORing of the signal of the flip-flop 12 and the signal of the delay circuit 13 by the OR circuit 17, and as a result, the pulse width is expanded. A black signal is formed by the AND circuit 18 using this extended long wavelength signal and the delay circuit 14. The long wavelength and short wavelength signals, that is, the signal that should be a blue recording signal and the signal that should be a red recording signal are blacked out in AND circuits 21 and 22, respectively. As a signal for this purpose, a signal obtained by inverting the signal from the AND circuit 18 by an inverter 19 is used. On the other hand, the signal from the AND circuit 18 is ANDed with the signal from the flip-flop 12 in an AND path 20, resulting in a black signal. The red, blue, and black signals are sent to a flip-flop 25, a delay circuit 24,
23, and is delayed by the distance interval between the mounting positions of the recording heads 29, 30, 31, and then transmitted to each drive circuit 28, 27, 26. Each drive circuit 2
At 6, 27, and 28, waveforms such as amplitude and pulse width for driving the recording heads are shaped, and each recording head 29, 30, and 31 is driven.

Until now, edges of black information were recorded in red due to differences in reading levels due to differences in the spectral sensitivity of the sensor, and images with blurred red or overlapping black and blue could not be achieved simply by adjusting the binarization level. However, by implementing the present invention, such a phenomenon has been eliminated.

The signal timing in the embodiment of the present invention explained in FIG. 1 will be explained using FIG. 2. 1 in FIG. 2 shows the pattern of the original. 2,3
represent the detection signals of the first sensor and the second sensor, respectively.

As explained in FIG. 1, the first sensor reads the red reflected light image, and the second sensor reads the blue transmitted light image. The two detection signals are binarized by comparators 10 and 11 and
become that way. As shown in the figure, the pulse width of the black information portion differs due to the difference in spectral sensitivity and slice level, and as shown in 6, the black signal had a pulse width narrower than the actual black information. Moreover, not only that, but the edge of black information ended up generating a red signal like 8. 9 shows a delayed waveform by the delay circuit 14 in FIG. 1, and 10 shows an output waveform from the OR circuit 17 in FIG. 11 is a black signal in which the present invention is implemented. The black, blue, and red recording signals processed using the 11 black-out signals are 12, 13, and 14.
As shown in FIG. 1, the AND circuit 22,
21 and 20, respectively.

As explained above, by implementing the present invention, the edges of black information are no longer contaminated by chromatic signals.

Furthermore, in the present invention, a plurality of color component signals obtained from the color sensor are combined to generate a prohibition signal that prohibits recording of a chromatic color signal for recording during a period including the vicinity of the boundary of the black component, and such prohibition signal is generated. Since the chromatic color signal is prohibited from being supplied to the color printer while the color is being displayed, it is possible to reliably prevent the edges of black information from being smeared with chromatic coloring materials and becoming hard to see. Can be reproduced with high quality.

Although the present invention has been described based on the above-mentioned embodiments, it is not limited to the above-mentioned embodiments within the scope of the claims. That is, in the above example, an embodiment was explained in which signals of three colors, black, red, and blue are read, but the present invention is effective even in the case of two colors of black and red, and furthermore, in the case of full color reading. This goes without saying. Furthermore, although the inkjet recording method has been described as the recording method, the present invention is also effective in other recording methods, such as electrophotographic recording methods using CRT or laser beams.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram for explaining the configuration of a copying apparatus which is one of the preferred embodiments of the present invention, and FIG. 2 shows the timing of signals in the apparatus of FIG. 1. FIG. 1... Original document, 2... Light source, 3... Imaging lens, 4... Dichroic mirror, 5, 6... Line sensor,
7...Clock generation circuit, 8, 9...Amplification circuit, 1
0, 11... Comparator, 12, 25... Flip-flop, 13, 14, 23, 24... Delay circuit, 15... Drum, 16... Delay instruction circuit, 17...
OR circuit, 18...AND circuit, 19...inverter,
20, 21, 22...AND circuit, 26, 27, 2
8... Drive circuit, 29, 30, 31... Recording head.

Claims (1)

[Scope of Claims] 1. A color sensor comprising a plurality of sensor element groups having mutually different wavelength sensitivity characteristics and converting a target image into a plurality of color component signals, a color sensor for recording from a plurality of color signal components obtained from the color sensor. processing means for generating a black component signal and a plurality of recording chromatic color component signals; a processing means for generating a black component signal and a plurality of recording chromatic color component signals; combining the plurality of color component signals to suppress the generation of chromatic color components at the boundary portions of the recording black component signals, including signals near the boundary portions; generation means for generating a prohibition signal for prohibiting recording of the recording chromatic color component signal for a period of time; and prohibition means for prohibiting supply of the chromatic color component signal to the color printer while the prohibition signal is being generated; An image reading device comprising: