JPH06105140A - Image forming device - Google Patents

Abstract

PURPOSE:To surely prevent forgery by slowing down a picture reproduction speed when a picture is possibly a picture being a picture recording prohibit object to discriminate whether or not the picture is the picture of prohibit object with precision and applying invalidating processing to the picture when the picture is the prohibit object picture. CONSTITUTION:A color masking section extracts a specific color from read picture data, the data are binarized by a binarization section and stored in a bit map memory. Furthermore, picture data for preliminary discrimination stored in a ROM are transferred to a pattern storage RAM, two data are compared by a pattern matching section and gives a discrimination result as to whether or not the both are coincident to a CPU. When the both are coincident, since an original is possibly a banknote, the main discrimination is executed. At first, a read speed of image reader section is set to a slower speed than the usual speed, the processing above is executed similarly to the case of the preliminary discrimination and pattern matching in every direction is executed within a time Tb. When the pattern in the bit map memory is coincident, the original is recognized to be a banknote and invalidating processing is implemented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a digital color copying machine. More specifically, the present invention relates to an apparatus capable of preventing forgery of banknotes or securities and capable of forming an image at a normal speed when the original is not a banknote.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 55-111977 discloses a copying machine capable of preventing forgery of banknotes, checks, securities and the like. This copying machine detects a pattern of a document during a copying operation and compares it with a predetermined pattern for which copying is prohibited. If they match each other, the image formation on the paper is prevented. It is the device

Japanese Unexamined Patent Publication No. 2-73283 discloses an image recording apparatus capable of preventing counterfeiting of banknotes, checks, securities and the like. This device detects whether a document image is a copy-prohibited document during image reading / recording operation, and when it is determined that the document image is a copy-prohibited document, the image recorded up to that time is determined. On the other hand, it is a device that performs invalidation processing such as overwriting solid black.

[0004]

All of the above-mentioned devices make a judgment during the copying operation and, when it is judged that the original is a copy-prohibited object, carry out invalidation processing such as image erasing. However, it generally takes a long time to determine whether the document is a copy-prohibited document. This is because the original is not always placed at a regular position at a regular angle, but may be placed at an angle. This is because it is necessary to perform matching.

Therefore, in the above-mentioned apparatus, even if the original is not the copy-prohibited original, the copying operation takes a long time. The present invention has been made in view of such circumstances, and it is possible to perform image recording at a normal speed when it is clear that the original is not a copy-prohibited object.
Another object of the present invention is to provide a device that can reliably prevent copying of a manuscript for which copying is prohibited.

[0006]

An image forming apparatus according to the present invention comprises image reading means for generating an electric signal corresponding to an original image, and image recording means for reproducing an image corresponding to the electric signal on a sheet. Preliminary detection means for determining whether or not the image corresponding to the electric signal may be an image for which image recording is prohibited, and the sheet by the image recording means if the preliminary detection means determines that there is the possibility. Control means for changing the upward image reproduction speed slower than usual, and if the preliminary detection means determines that there is the possibility, the control means changes the image reproduction speed during the image reproduction operation. Main detection means for determining whether or not the image corresponding to the electric signal is an image for which image recording is prohibited, and when the main detection means determines that the image is for image recording prohibited, And a disabling processing means for performing invalid processing an image to be reproduced by the image recording means.

In the above, the determination of the possibility by the preliminary detection means is performed based on, for example, whether or not there is the same pattern as the contour of the image for which image recording is prohibited. Further, the image invalidation processing by the invalidation processing means includes image erasing processing, transformation processing, overwriting processing, color conversion processing, and the like.

[0008]

The preliminary detection means determines whether or not the original image may be an image for which image recording is prohibited. This determination is sufficient if the outline of the image is examined, and the required time is short. If the above judgment (preliminary judgment) indicates that the above possibility exists, the image reproduction speed on the paper is slowed by a command from the control means, and the image reproduction operation is performed in parallel with the delayed image reproduction operation. , Whether or not the original image is an image for which image recording is prohibited,
This is determined by the detection means. This determination (main determination) requires a long time because it is performed strictly, but since the image reproduction speed is changed and slowed as described above, it can be determined before the completion of the image reproduction operation. Further, in the above-mentioned main determination, when it is determined that the document corresponds to the image recording prohibition target, the invalidation processing unit performs the invalidation processing on the reproduced image.

[0009]

EXAMPLES Examples of the present invention will be described below. In the apparatus of the present embodiment, the preliminary determination is performed during the prescan, and as a result, when it is determined that the original image may be an image for which image recording is prohibited, C, M, Y, and Bk are used. The original scanning speed and the image forming speed for each color are set to be slower than usual, and the main determination is performed during that period. Further, when it is determined in this determination that the document is an image for which image recording is prohibited, "invalid" characters are printed instead of the image when the Bk toner is used for printing.

[1] Mechanism of Embodiment Device First, an outline of the mechanism will be described with reference to FIG. The apparatus of this embodiment comprises an image reading section (image reader section) 30 and an image recording section (printer section) 20.

In the image reading section 30, the original image is read and an electric signal is generated, and based on the electric signal, image data for driving a laser diode is generated. That is, a document placed on the platen glass 31 with its image surface facing downward is first exposed and scanned by the scanner 32. This allows
The image reflected light is photoelectrically converted into an electric signal corresponding to the original image by an image sensor (CCD) 33 mounted on the scanner 32. Next, this electric signal is input to the image signal processing section 34 and subjected to a predetermined process to be image data for driving a laser diode. This image data is sent to the print head controller 35. The scanner 32 is moved by the driving force of the pulse motor 36 during scanning.

In the image recording section 20, the electrostatic latent image written on the surface of the photosensitive drum 4 by the laser light L is displayed by the toner of the corresponding color (cyan C, magenta M, yellow Y, black Bk). After being developed respectively, they are transferred one after another onto the paper wound around the transfer drum 10 in sequence, and then fixed by thermocompression bonding by a fixing device 48. If it is determined that the document is an image recording prohibition target, the Bk toner
At the time of forming the electrostatic latent image for printing, not the image corresponding to the document but the "invalid" font pattern is written on the photosensitive drum 4 by the laser light L.

The laser light L is first output from the laser device 21 controlled by the print head controller 35. This laser light L is incident on the surface of the photosensitive drum 4 which is being rotated at a constant speed, and an optical system in the laser device 21 scans the photosensitive drum 4 in the axial direction. Have been guided. Therefore, an electrostatic latent image corresponding to the image data is formed on the surface of the photosensitive drum 4. The photosensitive drum 4 is uniformly charged on the upstream side of the incident position of the laser light L.

The electrostatic latent image formed on the photosensitive drum 4 is
Next, the developing device provided in the developing device 6 (developing device 6C for cyan toner, developing device 6M for magenta toner, developing device 6Y for yellow toner, developing device 6k for black toner).
And then visualized. The selection of the developing device is performed by a command from a CPU (described later). The vertical movement of the developing device 6 for setting the selected developing device at the developing position is performed by the driving force of the developing unit motor 61.

The developed and visualized toner image is then transferred onto the paper wound around the transfer drum 10 by the suction force of the transfer charger 14. Here, the sheet is pulled out from any one of the sheet trays 42 to 44 or the intermediate tray 50, and the timing roller pair 45 is fed by the transport roller group.
After being conveyed to, it is wound around the transfer drum 10 at a predetermined timing. In addition, 11 is a suction chuck for suctioning the paper.
Jars 16, 16 and 17 are static elimination chargers for paper separation, and 18 is a separation claw for paper separation. Further, the photosensitive drum 4 and the transfer drum 10 are synchronously driven by the drum driving motor 22.

The paper on which the toner images of maximum four colors (at full color) have been transferred in this manner is then peeled off from the transfer drum 10 and conveyed to the fixing device 48 by the conveyor belt 47.
After the image fixing process by thermocompression bonding is performed in the fixing device 48, the image is discharged to a paper discharge tray 49 outside the machine or an intermediate tray.
Stored in 50. If the reversing device 51 switches back before storing the image in the intermediate tray 50, the next image is formed on the back side. In addition, a group of transport rollers, a transport belt
47 and the like are driven by the main motor 41.

[2] Outline of Control of Embodiment Device Next, an outline of control of the embodiment device will be described with reference to FIG. 2 and with reference to FIGS. 1, 6 and 7. 2 is shown in FIG.
The outline of the processing by the CPU is shown, and the CPU issues commands to the image reader section and the printer section, respectively.

When the copy start is instructed, first, the paper is drawn out from the paper trays 42 to 44, wound on the transfer drum 10 and chucked, and the polygon mirror in the laser device 21. Is instructed to start the rotation of (S1
1). Next, the image reader unit is instructed to start a preliminary scan (scan for detecting the document size, type, etc.) (S13).

Further, preliminary discrimination is executed based on the image data read by the preliminary scanning (S15). This is a process of determining whether or not there is a possibility that the document image is a document whose image recording is prohibited (a banknote here, but the same applies to checks, securities, etc.). Details of the preliminary determination will be described later.

If it is determined in the preliminary determination in step S15 that the above possibility does not exist (S17; NO), a normal copying operation is instructed. That is, the image reader unit is instructed to set the image reading speed to the normal speed, and the printer unit is instructed to set the printing speed to the normal speed. (S21).

Thereafter, first, an image reading operation for the cyan toner is instructed to the image reader section and (S
23), the image forming operation by the cyan toner is instructed to the printer unit (S25). Further, when the image reading and image formation for the cyan toner are completed (S27; NO), the same command is issued for the magenta toner. Further, the same instruction is given for the yellow toner and the black toner. In this way, when the image reading and image formation for the four colors are completed (S27; YES), the paper is peeled from the transfer drum 10,
After the fixing process is performed by the fixing device 48, the output tray outside the machine
It is discharged to 49 (S43).

On the other hand, if it is determined in the preliminary determination in step S15 that the above possibility exists (S17; YES), the copying operation is instructed at a slower speed than usual, and the main determination is performed during that time. To be executed. This main determination is a process of strictly determining whether or not the original is a banknote. Details of this determination will be described later.

First, if the above possibility exists, the image
The printer unit is instructed to set the image reading speed to a slower speed than usual, and the printer unit is instructed to set the print speed to a slower speed than normal ( S31).

Next, an image reading operation for the cyan toner is instructed to the image reader section (S33), and the main discrimination is executed based on the read image data (S35). As a result, if the original is not determined to be a banknote (S3
7; NO), the electrostatic latent image formed on the basis of the image data is developed by cyan toner, and then transferred onto a sheet (S
51). Further, when the image formation for the cyan toner is completed (S53; NO), the same command is issued for the magenta toner, and when the original is not determined to be a bill by the image data for the magenta toner (S37; NO). ), As well as the Yellow Toner. If the document is not determined to be a bill by the image data for the yellow toner (S37; N
O) and Blacktoner are also ordered. In this way, when the image formation for the four colors is completed (S53; YES), the paper is peeled from the transfer drum 10, the fixing process is performed by the fixing device 48, and then the paper is discharged to the paper discharge tray 49 outside the machine (S43). )
.

On the other hand, as a result of any of the final determinations in step S35, if the document is determined to be a banknote (S37; Y
ES), the electrostatic latent image of the image data (for example, "invalid" character) read from the font memory is not the image data of the original read in step S33, but the photosensitive drum 4
Formed on the surface of. That is, the CPU issues a warning font switching command to the selector (FIG. 1), and in response to this, the selector does not read the read image data but the image data from the warning font generation unit. To the printer section.

In this way, an electrostatic latent image of the above-mentioned "invalid" character pattern is formed on the photosensitive drum 4, which is developed by the black toner and transferred onto the paper (S41).
. For example, as shown in FIG. 6, an "invalid" character is transferred onto a sheet by superimposing it on an image formed by combining cyan, magenta, and yellow. After that, a fixing process and a discharging process are performed (S43). In this way, the copying operation in the apparatus of this embodiment is executed.

[3] Details of Preliminary Judgment / Main Judgment Next, with reference to FIG. 4 showing the procedure of the preliminary judgment / main judgment, and with reference to FIGS. Details of this determination will be described.

When the preliminary scan is started by the image reader section (S61), the read image data is
Only the specific color (eg, the color of the stamp of the banknote) is extracted by the color masking unit, binarized by the binarizing unit, and stored in the bitmap memory (S63). Further, image data for preliminary discrimination stored in the ROM (for example, a ring pattern of a banknote seal)
(See FIG. 5) is transferred to the pattern storage RAM (S
65). The two pieces of data are compared by the pattern matching unit (preliminary discrimination), and the discrimination result as to whether they match or not is sent to the CPU (S67).

If the two do not match in the preliminary determination, (S
69; NO), the manuscript is clearly recognized as not a banknote.
In this case, the normal copying operation is executed as described above. That is, the image reader unit is instructed to set the image reading speed to the normal speed, and the printer unit is instructed to set the printing speed to the normal speed. (S21, Fig. 2). Here, the normal speed is
As shown in FIG. 3, the speed is such that the image reading / recording operation for one color is completed at the time To.

On the other hand, if they match in the preliminary discrimination (S69; YES), the original may be a bill, so
This determination is executed.

First, as described above, the image reader unit is instructed to set the image reading speed to a slower speed than usual, and the printer unit is set to have a printing speed faster than usual. Is instructed to set a slower speed (S3
1, Figure 2). Here, the slower speed than usual is a speed at which the image reading / recording operation for one color is completed at time Ts, as shown in FIG. 3, which is α (= α ′ + α It is a value that is set so that “) + 3Ts ≧ Th.

Here, α'is the required time from the detection of the preliminary discrimination result to the start of the main scan, as shown in FIG.
α "is the required time from the completion of the image formation of one color until the start of the image formation of the next color, and Th is the completion of the pattern matching with the reference patterns (below) of P1 to P8 in FIG. That is, by setting the time Ts in this way, the main determination can be completed before the development of the final print color Black Toner, and necessary processing (image recording of a document such as a banknote is prohibited). When the image is the target image, it is possible to execute processing for overwriting "invalid" characters, etc. (see S41 in FIG. 2).

Next, when the main scan is started, the read image data is processed in the same manner as in the case of the preliminary discrimination and stored in the bit map memory. Also, RO
Image data for main discrimination stored in M (example: pattern of stamp of banknote, here, 8 patterns with different inclination angles are prepared like P1 to P8 in FIG. 5). Are sequentially transferred to the pattern storage RAM (S71),
It is sequentially compared with the patterns in the bitmap memory.
(S73). In this way, pattern matching in all directions is performed within the time Th.

If the main judgment is completed while the pattern in the bit map memory does not match any of the above P1 to P8 (S77; YES), it is recognized that the original is not a bill. In this case, the process of overwriting the "invalid" character with the black toner (invalid process, S41, Fig. 2) is not executed. On the other hand, the pattern in the bitmap memory is P
If it matches with any one of 1 to P8 (S75; YES), the document is recognized as a bill, and the invalidation process (S41,
2) is executed. In this way, the preliminary discrimination / main discrimination is executed.

[4] Other Embodiments In the above embodiment, the discrimination is performed by the pattern matching, but this is performed by other methods such as magnetic detection, color histogram, spatial frequency pattern, shape recognition. The method such as Further, in the above embodiment, when it is determined that the document is a bill or the like as a result of this determination, the characters "invalid" are overwritten with the black toner, but instead of this, the image is erased. , Transformation, color conversion, etc. may be performed.

Further, in the above-mentioned embodiment, the preliminary discrimination is performed at the time of the prescan, but the case where the prescan is not performed is performed.
For example, the preliminary determination may be performed at the time of processing the cyan toner. In that case, the processing time after the magenta toner is required to be slower than the above, but depending on circumstances, the apparatus may be temporarily stopped to make the main determination.

[0037]

As described above, according to the present invention, whether or not there is a possibility that the original image is an image for which image recording is prohibited is promptly judged by the preliminary detection means, and if there is no possibility, the image is reproduced at the normal speed. Since the forming operation is performed, the copy efficiency does not decrease. In the case where the above possibility exists, the image reproduction speed on the paper is slowed down, and in parallel with the slowed image forming operation, it is determined whether or not the document is an image for which image recording is prohibited. Is determined. If the result of determination is that the image recording is prohibited, invalidation processing is executed for the image. Therefore, it is possible to reliably prevent forgery of bills and the like.

[Brief description of drawings]

FIG. 1 is a control block diagram of an apparatus according to an embodiment.

FIG. 2 is a flowchart showing an outline of control of the apparatus of the embodiment.

FIG. 3 is a timing chart showing the control timing of the embodiment apparatus.

FIG. 4 is a flow chart showing an outline of document discrimination control of the embodiment apparatus.
It is a chart.

FIG. 5 is an explanatory diagram showing patterns compared by the apparatus of the embodiment.

FIG. 6 is an explanatory diagram of a pattern printed out by the apparatus of the embodiment.

FIG. 7 is a cross-sectional view schematically showing the mechanism of the device of the embodiment.

[Explanation of symbols]

 4 Photosensitive Drum 6 Developing Unit 10 Transfer Drum 20 Image Recording (Printer) Section 21 Laser Device 30 Image Reading (Image Reader) Section 33 Image Sensor 35 Print Head Control Section

Claims (5)

[Claims] 1. An image reading unit for generating an electric signal corresponding to an original image, an image recording unit for reproducing an image corresponding to the electric signal on a sheet, and an image corresponding to the electric signal for which image recording is prohibited. When the preliminary detection means determines that there is the possibility, the image reproduction speed on the paper by the image recording means is slower than usual. When it is determined by the control unit that changes the image and the preliminary detection unit that the possibility exists, the image corresponding to the electric signal is recorded as an image during the image reproduction operation in which the image reproduction speed is changed by the control unit. A main detection unit that determines whether or not the image is a prohibition target image, and if the main detection unit determines that the image is an image recording prohibition target image, it is reproduced by the image recording unit. An image forming apparatus having a disabling processing means for disabling processing to the image, a. 2. The image forming apparatus according to claim 1, wherein the invalidation processing unit erases an image to be reproduced on a sheet by the image recording unit. 3. The image forming apparatus according to claim 1, wherein the invalidation processing unit deforms an image to be reproduced on a sheet by the image recording unit. 4. The image forming apparatus according to claim 1, wherein the invalidation processing unit causes an image reproduced on the paper by the image recording unit to be overwritten to the effect that the image is invalid. . 5. The image forming apparatus according to claim 1, wherein the invalidation processing unit executes color conversion processing on an image to be reproduced on a sheet by the image recording unit.