JP2749866B2 - Image forming device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image forming apparatus having a function of determining a specific image.

2. Description of the Related Art Conventionally, technical development of a hard copy such as a copying machine has been accumulated for the purpose of creating an image faithful to a document. As a result, color copiers that have excellent color reproducibility and can form reproduced images at a glance that are indistinguishable from original images have also been manufactured.

[Problems to be Solved by the Invention] However, if a reproduced image that is extremely close to the original image is obtained, it may be misused for forgery of banknotes, securities, and the like, which has a wide social impact. On the other hand, the conventional color copying machine cannot prevent image reproduction faithful to a specific image such as a bill.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus capable of preventing image reproduction faithful to a specific image such as banknotes or securities.

[Means for Solving the Problems] In order to solve the above-described problems, an image forming apparatus of the present invention is an image forming apparatus that forms an image of a plurality of color components constituting an image to be processed on a medium, Input means for inputting color image data representing a processing target image; determining means for determining whether the processing target image is a specific image based on the color image data input by the input means; When it is determined that the target image is a specific image, the image processing apparatus further includes a control unit that performs control to prevent formation of a faithful image of at least one color component, not all of the plurality of color components.

[Operation] In the above configuration, the determination unit determines whether a color image corresponding to the color image data input by the input unit is an image specified in advance, and the control unit determines that the determination unit When it is determined that the color image is the specific image, control is performed to prevent the faithful image formation of at least one color component, not all of the plurality of color components.

[Embodiment] Embodiment 1 A first embodiment of the present invention will be described below using a full-color digital copying machine as an example.

FIG. 2 is a diagram showing the overall configuration of a full-color digital copying machine. In FIG. 2, reference numeral 201 denotes a portion which reads an original by an image scanner and performs digital signal processing. Reference numeral 202 denotes a printer unit, and an image scanner unit 2
This portion prints out an image corresponding to the original image read in 01 in full color on paper.

In the image scanner unit 201, reference numeral 200 denotes a mirror pressure plate, and a document 204 on a platen glass (hereinafter, platen) 203 is
Irradiated by a lamp 205, guided to mirrors 206, 207, and 208, an image is formed on a three-line sensor (CCD) 210 by a lens 209, and full-color information red (R), green (G),
The signal is sent to the signal processing unit 211 as a blue (B) component.
Incidentally, 205 and 206 are speeds v, and 207 and 208 are 1/2 v, and the entire surface of the document is scanned by mechanically moving in the direction perpendicular to the electrical scanning direction of the line sensor. The signal processing unit 211 electrically processes the read signal, decomposes the signals into magenta (M), cyan (C), yellow (Y), and black (Bk) components, and sends them to the printer unit 202. In addition, for each original scan in the image scanner unit 201, one component of M, C, Y, and Bk is sent to the printer unit 202, and one printout is completed by a total of four original scans. I do.

M, C, Y or sent from the image scanner 201
The Bk image signal is sent to the laser driver 212. The laser driver 212 modulates and drives the semiconductor laser 213 according to the image signal. Laser light is polygon mirror 214, f-θ lens 2
15. Scan the photosensitive drum 217 via the mirror 216.

Reference numeral 218 denotes a rotary developing unit, which includes a magenta developing unit 219, a cyan developing unit 220, a yellow developing unit 221, and a black developing unit 222. The four developing units alternately contact the photosensitive drum 217 and are formed on the photosensitive drum 217. The developed electrostatic latent image is developed with toner.

Reference numeral 223 denotes a transfer drum which winds a sheet fed from the sheet cassette 224 or 225 around the transfer drum 223 and transfers an image developed on the photosensitive drum 217 to the sheet.

After the four colors M, C, Y, and Bk are sequentially transferred in this manner,
The sheet passes through the fixing unit 226 and is discharged.

FIG. 1 is a block diagram of a first embodiment of the present invention.
In FIG. 2, the signal processing unit 211 is located.

In FIG. 1, reference numeral 101 denotes a color processing circuit which performs processing for obtaining Y, M, C, and Bk signals, which are reproduced colors, from R, G, and B signals. A selector 102 selects one of the reproduced colors Y, M, C, and Bk. 103 is a feature extraction circuit for extracting features of the input image. Reference numeral 104 denotes a specific image data storage unit in which image data having predetermined characteristics is stored in advance. A determination circuit 105 compares the data extracted by the feature extraction circuit 103 with the data stored in the specific image data storage unit 104, and outputs a determination result. Reference numeral 106 denotes a coordinate signal generation circuit which generates a coordinate signal of an image by inputting the pixel clock CLK and the line cycle signal HSYNC. An OR circuit 107 sends a toner amount signal to the laser driver 212 when the output of the determination circuit 105 is “H” or when there is a color signal from the selector 102.

 In the above configuration, each unit performs the following operation.

The R, G, B color signals obtained from the CCD 210 are A / D converted and input to the color processing circuit 101. In this color processing circuit, R,
From the G and B signals, toner amount signals M, C, Y and Bk corresponding to the reproduced colors
A process for obtaining a signal is performed, and specifically, a UCR process for generating a Bk signal, a masking process for correcting a spectral characteristic of each toner, and the like are performed.

Next, among the C, M, Y, and Bk signals, a signal corresponding to the development color of the printer is selected by the selector 102.

On the other hand, the digital color signals R, G, B are input to the feature extraction circuit 103, and the features of the input image are extracted. This feature extraction circuit 10
In 3, the features of the input image are extracted according to a predetermined algorithm. Specifically, the feature extraction process is performed by paying attention to a specific pattern or a specific color of the input image, a color distribution, and the like. The feature data extracted by the feature extraction circuit 103 and the image whose copy is to be prohibited are processed by the same algorithm and feature data 104 previously extracted.
Are compared and examined by the decision circuit 105, and a decision result is output. In the present embodiment, when it is determined that a specific image is present, the determination signal becomes “H” (High), and the image signal output from the selector 102 is gated by the OR circuit 107 and the laser driver 212
The output signal is always "H" and an image filled with the developing color toner is output, so that copying of the specific image can be prohibited.

The coordinate signal generating circuit 106 receives the pixel clock CLK and the line synchronization signal HSYNC and generates a coordinate signal of an image. By inputting this coordinate signal to the determination circuit 105, only a specific area in the image can be painted out.

Next, the control flow of this embodiment will be described with reference to the flowchart of FIG.

When copying is started, the developing device M219 is selected as a developing color. Next, the reading scanner 201 scans the original, and the image signals R, G, and B read by the CCD 210 are input to the signal processing circuit 211. As described above, the R, G, and B signals are subjected to color processing, and the M signal is selected from the toner signals M, C, Y, and Bk and sent to the laser driver 212. At this time, R, G, B
The characteristics of the document are extracted from the signal and the determination is made. However, since the final determination result is obtained when the original scanning is completed, the M signal is not gated. That is, the M signal is applied to the drum 2 by the laser 213 in the normal processing.
A latent image is formed on 17 and development and transfer are performed.

Next, the C developing device 220 is selected as the second color.
When it is determined that a specific image is present on the original by scanning, the output of the determination circuit 105 becomes "H", and the entire surface or a part is painted with C toner, and at that time, the image is fixed, discharged, and the copy operation is completed. I do.

On the other hand, if it is determined in M scan that there is no specific image, normal copy control is performed, and C toner is developed and transferred according to the image signal. Here, the determination of the specific image is performed again. This process may be skipped and the copy operation may be unconditionally performed with Y and Bk only after the M scan, but may be performed again here to increase the reliability. In addition, the range of detection can be widened and the reliability of detection can be increased by changing the conditions of the M scan and the conditions of feature extraction, determination conditions, or the detection image itself.

Similarly for Y, control of the Y signal and the copy operation is performed based on the determination result obtained in the C scan. Bk similarly controls the Bk signal and the copy operation based on the determination result obtained in the Y scan. However, since the determination result at the time of scanning cannot be reflected on the final color Bk, the normal copy operation is performed without performing the determination process.

The control flow shown in the flowchart of FIG. 3 is characterized in that a copy prohibition operation can be performed without distorting normal copy control.

FIG. 4 is a flowchart showing another control different from that of FIG. That is, in FIG. 4, the setting of the developing device is not performed until the determination result is obtained, and when it is determined that the specific image is present, painting is performed with the same color toner as the determination scan. In this method, the determination process can be performed up to four times, so that the reliability of the determination can be further increased. This control method is a control method suitable for a device that performs a determination process in which a determination result is output relatively quickly.

Also, in FIGS. 3 and 4, it has been described that the entire surface is painted when it is determined that there is a specific image. However, as described in the block diagram of FIG. 1, only the target image area can be painted using the coordinate generation function. It becomes possible by doing.

The control method shown in the flow of FIG. 5 is such that when it is determined that a specific image is present, it is always filled with Bk toner.

The feature of this method is that black toner is used as the filling color, so that it is possible to completely fill the color regardless of what color toner has been transferred before the determination.

Therefore, even if there is an error in the determination in any of the scans of M, C, and Y, the specific image can be painted in black.

As described above, according to the present embodiment, a copying apparatus, particularly a full-color copying machine, is provided with a unit for recognizing a specific image such as a bill, securities, etc., and performs image recognition processing during a copying operation. If it is determined that all or a part of the copy paper is a specific image, the forgery of banknotes, securities, etc. is prevented by painting all or a part of the copy paper with the developing toner or the specific color toner during the copy operation. be able to.

If it is determined that the image is a specific image, the result is displayed on the display, which is convenient for the operator because it is possible to know in advance that an image in which all or a part of the copy paper is filled is reproduced.

Embodiment 2 FIG. 6 is a block diagram showing a second embodiment. Sixth
In the figure, 101 to 107 are the same as those in FIG. The specific pattern generation circuit 108 outputs a specific pattern when the output of the determination circuit 105 becomes “H” (High). Forgery and the like are prevented by combining the pattern signal and the image signal with the OR circuit 107. Can be.

The pattern may be, for example, a periodic pattern such as a lattice or a halftone dot, or a specific character pattern such as a “sample”.

As for the control flow, as in the first embodiment, the color may be filled with the toner of the color next to the color determined as shown in FIG. 3 or the color toner of the color determined as shown in the flow of FIG. It may be painted, or may be painted with black toner or a fixed color toner at all times as shown in the flow of FIG.

The feature of the second embodiment is that the first embodiment cannot discriminate a specific image from a reproduced image irrespective of the presence or absence of an operator's intention to forge, because the first embodiment paints part or all of a copy. Since it is not painted, if the pattern to be synthesized is appropriately selected, an output result which can be sufficiently used for conventional purposes such as documents can be obtained.

However, in this case, even if it is determined that the specific image is present and the pattern is synthesized as shown in FIG. 7, if the copy operation is terminated there, an incomplete reproduced image is obtained. Regardless of M, C, Y, Bk 4
It is necessary to develop and transfer colors.

Embodiment 3 FIG. 8 is a block diagram of a third embodiment of the present invention.
While the previous two embodiments add a specific image signal to all or part of an image signal when the presence of a specific pattern is recognized, the third embodiment adds the entire image signal or one of the image signals. Part is not output.

In FIG. 8, reference numerals 101 to 104 and 106 are the same as those in FIG. In this embodiment, the determination circuit 105 outputs 0 when it is determined that the image is a specific image, and outputs 1 when it is not a specific image. Then, the AND circuit 110 sends the color toner amount signal to the laser driver 212 only when the image is not determined to be the specific image and the output from the selector 102 is 1. If it is longer than this, the color toner amount signal is not sent.

As described above, according to the present embodiment, when it is determined that a specific image is present in the document, the toner of the specific color or all the image toners may not be output to all or a part of the copy paper. Forgery of paper money, securities, etc. can be prevented.

In particular, by not filling the specific image, there is also an effect that the decrease in the amount of the color toner is small.

[Effects of the Invention] As described above, according to the present invention, it is possible to prevent faithful image reproduction of specific images such as banknotes and securities by performing the necessary minimum processing.

Moreover, since the color components of a part of the processing target image are faithfully reproduced, the processing target image can be inferred from the reproduced image.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention, FIG. 2 is a basic configuration diagram of a digital full-color copying machine, FIG. 3 is a control flowchart of the first embodiment of the present invention, and FIG. FIGS. 4A and 4B are control flow charts of the first embodiment of the present invention, FIG. 5 is a control flow chart of the first embodiment of the present invention, and FIG. 6 is a second embodiment of the present invention. FIG. 7 is a control flowchart of a second embodiment of the present invention, and FIG. 8 is a block diagram of a third embodiment of the present invention. 101: color processing circuit 103: feature extraction circuit 105: determination circuit 108: specific pattern generation circuit 201: scanner unit 202: printer unit 210: CCD sensor 211: signal processing unit 213: laser 219 ~ 222 ... M, C, Y, Bk developing unit

Claims (4)

(57) [Claims] 1. An image forming apparatus for forming an image of a plurality of color components constituting an image to be processed on a medium, comprising: input means for inputting color image data representing the image to be processed; Determining means for determining whether or not the processing target image is a specific image based on the color image data obtained, if the processing target image is determined to be a specific image by the determining means, An image forming apparatus comprising: a control unit configured to perform control for preventing formation of a faithful image of at least one color component. 2. An image forming apparatus according to claim 1, wherein said control means sets at least one color component to have the same density in a specific area of an image to be formed. 3. The image forming apparatus according to claim 1, wherein the control unit does not form an image of at least one color component in a specific area of an image to be formed. 4. The image forming apparatus according to claim 1, wherein said control means adds a predetermined pattern to at least one color component in a specific area of an image to be formed.