JPH11268381A - Image forming device and method for preventing unfair copying in image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent unfair copying even if data of images picked up by an image scanner are taken into PC, where the data are processed and printed by a color printer. SOLUTION: A recognition is obtained from the data given when image data are taken into a color laser printer 300, where the image data are developed to raster data at an internal image processing block 350, and if an unfair thing is recognized, toners remaining on a photosensitive drum 302 are removed by a photosensitive drum cleaner 304, and toners remaining on an intermediate transfer belt 320 are removed by an intermediate belt cleaner 321.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus having an illegal copy preventing function and an illegal copy preventing method.

[0002]

2. Description of the Related Art As a conventional apparatus for preventing unauthorized copying of bills and securities, there are the following apparatuses. The input device, the image processing device, and the output device are configured on one system, and are only mounted on a copying machine and a copying system that can perform unauthorized copying (illegal copying) from an original in one pass.

In such a copying machine, a copy-inhibited object is recognized by using image data captured by an input unit, a so-called scanner unit, and copying is prohibited in a process after the input unit. . One example is a painting process in the output device section. There is also a method of stopping the output.

[0004]

However, in recent years, personal computers (PCs) have become cheaper and more sophisticated, hard disks (HDs) mounted on the PCs, larger memories, and color laser printers (CLBPs). Due to the high image quality and low price, an environment has been established in which illegal copying can be performed without using expensive copying machines. By taking an image into a PC using an image scanner (IS), performing image processing on the PC, and printing using CLBP,
Unauthorized copying comparable to a color copying machine (CPPC) is becoming possible. At present, no countermeasures have been taken against this kind of illegal copying, and a response by CLBP is urgently required.

[0005] In copying by such a system, since the copying action is not a continuous operation, it is not possible to use a method of performing recognition using data of the image input section and prohibiting the recognition at the output section. There is a problem that a new recognition method and a prohibition means are required. The present invention has been made in consideration of the above problems, and prevents unauthorized copying even when an image is taken into a PC by an image scanner, processed by the PC, and printed using a color laser printer. It is an object of the present invention to provide an image forming apparatus capable of performing the following.

[0006]

An image forming apparatus according to a first aspect of the present invention captures electrophotographic image data and outputs the image data by a printer in an image forming process. An unauthorized copy recognizing means for recognizing whether or not image output should be prohibited; an unauthorized copy preventing means for removing development of one or more colors on the image forming body in response to the unauthorized recognition of the unauthorized copy recognizing means; It has.

[0007] The illegal copying here includes illegal printing, illegal printing, illegal printing, and the like. The image forming body corresponds to a photosensitive drum, a process color, an intermediate transfer belt, a transfer drum, or the like inside a printer or the like. Further, a method for preventing unauthorized copying of an image forming apparatus according to claim 7 is a method for preventing unauthorized copying of an image forming apparatus which takes in electrophotographic image data into an image processing unit, forms an image with a printer, and outputs the image. In the process of forming an image, it is determined whether or not image output should be prohibited, an unauthorized copy is recognized, and in response to the recognition of the unauthorized copy, development of one or more colors on the image forming body is removed. ing.

[0008] The illegal copy and the image forming body here are the same as those described above in relation to the first aspect.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to embodiments. FIG. 1 is a diagram showing a device configuration of a system according to an embodiment of the present invention. In FIG. 1, the system includes a scanner 505, a personal computer 506,
And an image forming unit 300. PC 50
Reference numeral 6 denotes a path for transferring image data read by the scanner 505 to a path 5.
02, or image data from another personal computer 507 via a path 503, is sent to the image forming unit 300 from a path 501, and the image forming unit 300 copies the image data. Also, image data can be sent from the scanner 505 to the image forming unit 300 via the path 504 and copied by the image forming unit 300. Specifically, for example, a color printer is used as the image forming unit 300.

FIG. 2 is a diagram showing a basic configuration of a color printer used in the system of this embodiment. The color printer 300 employs a drum transfer system, and includes a controller (internal image processing block) 350 for receiving print data from an external path 351 and an exposure unit laser 3.
01, a polygon mirror 305, an exposure unit (developing unit) photosensitive drum 302, an exposure unit charger 303, an exposure unit (developing unit) photosensitive drum cleaner 304, and a development process color (YMCK) toner cartridge 311 to 314. ,
Intermediate transfer belt 320 and intermediate belt cleaner 321
A paper path 331 from the manual feed tray, a paper path 332 from the paper feed cassette, a paper feed roller 335,
A path 330 of the sheet after transferring the developed toner to the sheet,
The fixing device includes a fixing oil roll 342, a fixing device 340, a paper path 333 to the side discharge tray, and a paper path 334 to the upper discharge tray.

FIG. 3 is a diagram showing a basic configuration of another color printer used in the system of this embodiment instead of the above color printer. This color printer 1300
Also adopts the drum transfer method, and the external path 13
51, a controller (internal image processing block) 1350 for receiving print data, an exposure section laser 1301, a polygon mirror 1305, an exposure section (developing section) photosensitive drum 1302, an exposure section charger 1303, and an exposure section (developing section). ) Photosensitive drum cleaner 1304 and developing process color (YMCK) toner cartridges 1311 to 1314
, Intermediate transfer drum 1320 and transfer drum cleaner 1
321, a paper path 1331 from the manual feed tray,
A path 1332 for the sheet from the sheet cassette, a sheet feeding roller 1335, a path 1330 for transferring the developed toner to the sheet, a fixing oil roll 1342, and a fixing unit 13.
40, a path 1333 for the sheet to the side sheet ejection tray, and a path 1334 for the sheet to the top sheet ejection tray.
Instead of the intermediate transfer belt 320 of FIG.
20 is different from that of FIG. 2, but the printing operation is almost the same.

The printing operation by the color printer 300 (1300) is performed as follows. First, the print data is transferred to the printer 300 from the path 351 (1351).
(1300). Printer 300 (130
0) is input to the controller 350 (1).
In step 350), the raster image data is developed.
This data is input to the laser unit 301 (1301), and a laser beam for exposure is emitted. The laser beam is applied to the photosensitive drum 30 by the polygon mirror 305 (1305).
2 (1302). Details of this exposure unit are omitted. It is well known that an exposure unit is formed by an optical system such as an Fθ lens. It is well known that there is an exposure method using an LED instead of a laser beam.

On the photosensitive drum 302 (1302), after being uniformly charged by the charger 303 (1303),
An image is formed by the irradiated laser. At this point, the image is formed by electric charges in an invisible state.
This is called exposure. Next, each process color 311 to 311
A visible image is formed on the photosensitive drum 302 (1302) by the toner of No. 14 (1311-1314). This is called development. The laser beam is the process color 311-
Irradiation is performed four times every 314 (1311-1314), and a total of four exposure and development steps are performed.

The developed image is transferred to an intermediate transfer belt 320
(Transfer drum 1320). The toner remaining on the photosensitive drum 302 (1302) after the transfer is removed by the photosensitive drum cleaner 304 (1304). When the development and transfer for each of the process colors 311 to 314 (1311 to 1314) are completed, the sheet feeding roller 335 (1) is supplied from the path 331 (1331) or the path 332 (1332).
335), the image is transferred to the sheet that has passed.

When an image is formed on the sheet, the sheet is heated by the heater of the fixing unit 340 (1340), and the toner is melted to fix the image on the sheet. At this time, the fixing device 34
0 (1340) so that the toner does not adhere to the fixing device 340 (1) by the fixing oil roll 342 (1342).
340) is supplied with oil. After fixing,
The paper is discharged to the outside of the printer through the paper discharge paths 333 (1333) and 334 (1334). Intermediate transfer belt 320
The toner remaining on the (transfer drum 1320) is removed by the intermediate belt cleaner 321 (transfer drum cleaner 1321).

FIG. 4 is a block diagram showing an internal configuration of a printer controller 350 (1350: hereinafter the same, so the correspondence is omitted) of the color printer of the embodiment. The controller 350 has a communication port (eg, serial, parallel, SCS) for receiving data input 351 to the printer.
I, IEEE 1394, USB etc) 360, a protocol receiver / command interpreter 361, a main CPU 362, and an image processing ASIC (sub CPU) 3.
63, a DRAM / SRAM 364, a color conversion table ROM 365, an image processing table ROM 366, an engine output controller 367, a bus 370, and an output 352 to an engine unit (laser).

The processing operation of the printer controller 350 will be described. Image data is input to the printer using a communication protocol such as serial, parallel, or SCSI. The image data is stored in various formats (ex. Postscript L) by the driver in the PC.
evel12) in many cases, and in many cases, measures such as image compression are also applied.

Data input to the communication ports 360 of the various I / Fs is taken into the printer through the communication protocol receiver 361. This part has a command interpreter and a printer language (postscript).
Etc.). The captured data is stored in the main CPU 362, the sub CPU or the ASIC 36.
3. A rastering process is performed by the memory 364. Here, the term “rastering” refers to developing image data described in a printer language or the like into raster data for image formation. In addition, at the time of this rastering, in many cases, smoothing processing of character data, color conversion into a process color (RGB → YMCK), and gradation processing for printing are also performed. Here, a block diagram was created by performing these conversions using a table. That is, the color conversion table ROM 365, the image processing table R
These processes are performed by the OM 366, the image processing ASIC 363, and the like.

Here, the gradation processing will be briefly described. Consider a printer with a resolution of 600 dpi. Resolution 6
00 dpi is 25.4 mm / 600 when converted to an area.
= 42um square. The diameter of the color toner is about 7 μm. For example, even if the intensity of the laser beam can be changed, only the number of 6 × 6 = 36 toners can be controlled. However, the gradation expression needs to be as close as possible to the original 256 gradations of each of the multi-valued gradations. To solve this inconsistency, several 600 dpi resolutions are collected to increase the pseudo gradation expression. Take (area gradation), 6
The gradation reproducibility is enhanced by controlling one dot with a resolution of 00 dpi more finely in the laser operation direction (PWM: pulse width modulation).

FIG. 5 shows an example of the area gradation. here,
By solidifying 3 × 3 pixels of 600 dpi, 20
The gradation reproducibility is enhanced at the line number of 0 lpi.
FIG. 6 shows an example of the PWM. Here, as shown in FIG. 6, the area of 600 dpi is further divided into eight equal parts in the scanning direction of the laser beam. Laser beam is laser 4
03 (301), polygon mirror 404
The image is scanned at (305) and irradiated onto the photosensitive drum 302. Reference numeral 406 represents the trajectory of the laser beam.

Reference numeral 402 denotes an enlarged minimum point on the photosensitive drum 302. Here, the laser beam to be irradiated simultaneously with the above-mentioned eight equal divisions is controlled. That is, 407
, It is possible to apply finer control with a resolution of 600 dpi. In practice, they are used in combination and are generally well-known techniques.

-Acquisition of Multi-Valued Image Data- As described above, various image data other than the RGB multi-valued image data exist inside the color printer. of course,
These data also exist in the printer unit inside the color copier, but in the case of the copier, the RGB multi-valued data can be easily read from the path connecting the scanner unit and the printer unit as the place where the data for recognition is taken in. Can be obtained.

-Acquisition of multi-valued image data by printer-However, in the printer, as described above,
Conversion into a language, compression, and the like are performed in a PC, and it is difficult to obtain RGB multivalued raster data at the entrance of a printer as in a copying machine. Here, a method of performing recognition using RGB multivalued raster data as in the case of the color copying machine will be described. Printer controller 35
0, at least the engine power controller 36
At time point 7, raster data exists. However, it is data on any one plane of the process color YMCK. First, on the bus 370 or the RAM 36
Consider 4 above.

-YMCK conversion- Conversion to process color requires all RGB data. For example, when making M (magenta), it is as follows. m = 255-G; 256 gradations, G is the original reflected light, the reflected light max is 255, and min is 0. m is the basic density of magenta, and 0 is the magenta density of 0.

K = min (y, m, c); UCR (Un
Black density basic value for der Color Removal (under color removal) M = m-UCR (k); M is magenta density, UCR
() Is a function for removing under color and the variable is k. Thus, even when M is made, not only the complementary color G but also RB
Is necessary (to obtain y, c). Also, in practice,
Since the RGB and the spectral characteristics of the toner do not match, conversion is performed using a more complicated table. Focusing here,
At the time of conversion to process color, RGB multivalued data always exists, and after process color conversion, raster data always exists.

Next, several recognition methods which can be employed in the color printer of the image forming apparatus of the above embodiment will be described. -Recognition method [1]-If the data of the entire image data is input, the controller 350 performs the color conversion while developing the raster data. Therefore, if a recognition device is connected to the bus 370 and data is captured together with a signal (coordinate data may be used or a flag indicating continuity) that can specify the coordinates of the image data, raster data can be obtained in the same manner as a copying machine. Recognition processing can be performed using data.

-Recognition method [2]-Consider the case where the image data is not the whole image data. 41 in FIG.
In general, when an image is formed as shown in FIG. 1, data is sent in a format such as 412. Along with the coordinate position, text and images are divided into areas and sent. The command interpreter 361, the CPU 362, and the like use the internal font ROM (equivalent to 365, 366, etc.) to develop the text data into an image,
Expand on 64. The image part is sent for each block,
364. The same applies to the non-printed portion. This image is shown in FIG.

In this case, each block to be developed is treated as one image, and the same recognition processing as that of the copying machine is performed for each block, so that the recognition processing can be performed simultaneously with the rastering processing. -Recognition method [3]-Of course, at the time of text data rastering, the recognition operation is not performed, and erroneous recognition can be prevented.

Misrecognition refers to recognizing an object that is not an illegal copy as an unauthorized copy, and reducing such misrecognition by removing objects that are clearly not an unauthorized copy such as character data. Becomes possible. Up to this point, a method of performing recognition at the same time as the rastering process has been described.

-Recognition method [4]-It is also possible to perform recognition using data at another place. In the above description, it has been described that the memory unit 364 stores data for each process color. A case where recognition is performed using these colors will be described. It is assumed that the rasterized data is one color of YMCK and is multi-valued in the memory. That is, the gradation processing is performed when output from the engine output controller 367.

Therefore, recognition processing similar to that of a copying machine is performed for each color. Of course, in the case of a copying machine, recognition is performed using all data of the additive color mixture of RGB, which is different from recognition using one data of the subtractive color mixture in this case. But,
Even in the case of performing recognition using all the additive color mixture data, a threshold value is provided for each of the colors R, G, and B, and the color is determined by combining them. In the case of a printer, the difference is that the mixed color data does not exist in parallel but only exists in serial. By retrieving multi-valued Y, M, C, and K data from the bus 370, the same recognition as in a copying machine is performed. Can be realized. When YMCK and image data are present as indicated by 441 in FIG. 9, however, there is a possibility that it is necessary to memorize each color intermediate processing data (for example, averaged data and binary data) during the recognition processing. In this case, additional memory needs to be added. During the period from 442 to 444, it is necessary to store the intermediate processing data for each color. Of course, instead of the intermediate processing data, the data may be stored as multi-valued data as it is. However, since the memory capacity becomes enormous, the intermediate processing data is stored. 445 is an internal process;
Although it is not necessary to store it in the memory, it is shown here to clearly show that the intermediate processing is being performed. The recognition process is performed during the period of 446.

-Recognition method [5]-A method for further reducing the capacity of the memory added in [4] will be described. To store all the intermediate processing results for each color requires a very large amount of memory. Therefore, the recognition process is completed for one color until the end, and the recognized coordinate position is stored. If the recognition results for each color are compared and the final result is output, the memory capacity can be reduced. That is, 442 to 444 in FIG. 9 are not intermediate processing data but memories for storing recognition results for each color.

-Recognition method [6]-When the method of [5] is adopted, there is a possibility that a pattern that cannot be recognized to the end with one color may occur later. Therefore, a method is adopted in which the result of the intermediate processing performed for each color in [4] is combined with the intermediate result of the previous color, and is always transmitted as one-color data to the processing of the next color. Y, M,
The memory required for three colors C and K can be reduced to one color. FIG. 10 shows a conceptual diagram. Image data 4
41 is obtained as before. Although the intermediate processing results are stored independently in FIG. 9, they are sequentially stored while being combined, considering that they are ultimately combined and used. Reference numerals 462 to 464 in FIG. 10 indicate the stored contents. Although 465 in FIG. 10 is not stored, it is data used for actual recognition processing, and is shown for easy understanding.

-Recognition method [7]-The recognition methods described so far do not propose recognition based on print data itself. The data output from the controller 350 basically drives only the laser beam and is not subjected to any new image processing. However, the RGB data before color conversion may be different from the color space to be recognized depending on the color conversion.

There is a possibility that YMCK multi-value data cannot be obtained by a controller designed to perform gradation processing simultaneously. Therefore, Y, M,
A method for performing recognition using C and K data is proposed. A place where the data is taken in is a memory section 364 for storing rasterized data after gradation processing, or an engine output controller section 367 for controlling a laser beam.

The recognition method in this part is described in [4] to [6].
Is the same as However, the image data is data for laser driving, and the number of gradations per resolution is reduced. Extremely speaking, laser ON / OF at 600 dpi
There is a possibility that the value is changed to binary for switching F. However, in most printers, the PW as shown in FIG.
M control is performed, and the resolution is substantially 4 to 8 times in the scanning direction. Therefore, if the laser control signal is converted into a multi-value (multi-gradation) and used for recognition, the same recognition as in the above [4] to [6] can be performed.

Here, some of the multi-value conversion methods will be described. The method of multi-gradation is as follows. For example, in the case of 402 in FIG.
It is ON in the area, and 9 levels indicate 5 levels of gray levels. The right area 47 in FIG.
Consider how PWM 2 is PWMed. Six areas are turned on. As a method of riding the toner, a shape like a waveform 475 in FIG. 11 is expected.

Then, here, the peak is (5+
6) It is considered that the density spans 11 areas + 4 areas (left and right margins before dropping to 0) at a density of / 16. Therefore, the density is distributed to each area divided by PWM from the peak to 0. The distribution method may be a form like a normal distribution, a linear approximation, or a table reference.

An example of the case of performing linear approximation is shown in FIG.
FIG. For example, in FIG.
11 areas are ON with 2 pixels of 600 dpi,
If the position of pixel division is shifted, all eight areas are O
This is because there is a possibility that N was performed. Next, consider the change on the left. If the number of ON areas of the pixel indicated by 477 in FIG. 11 is 0, it is considered that the pixel 471 in FIG. 11 is inclined toward the 0 level.

It is assumed that a margin of two areas is provided outside the ON area, and that the density changes with an inclination as indicated by 478 in FIG. This straight line y = ax is represented by y = 8 at
x = 7, y = 0 atx = 0, and a = 8/7.
Therefore, the straight line 478 becomes y = 8x / 7, and a density conversion value for each divided area is obtained. Here, since each density value has significant digits after the decimal point, multiplication of the coefficient as a whole yields multivalued data of eight or more values.

The same applies to the conversion to the 472 side in FIG.
In this example, for simplicity, linear approximation was performed.
A gamma curve or a normal distribution may be used. In this example, the case where all the areas 477 in FIG. 11 are OFF has been described. If there is an area in which 477 in FIG. 11 is ON, the calculation performed when y = 0 atx = 0 is calculated, for example, as y = 4 atx = 0.

For example, in the case of 479 in FIG. 11, four consecutive areas are OFF, and it is considered that the density is 4. -Recognition method [8]-In the above-described recognition method [7], a method of performing recognition processing after performing multi-value processing has been described. As described above, the intermediate processing is performed inside the recognition processing, and the recognition processing is often performed by lowering the resolution by, for example, averaging processing. Therefore,
This data is handled as binary high-resolution data without multi-value conversion (2400 to 4800 dpi described above).
Thereby, it is also possible to perform a recognition process.

Next, a method of preventing output of the color copying machine will be described. Even in electrophotographic color copiers,
The basic image forming process is the same as that described for the color printer. For a color copying machine, the copying process is as follows. As shown in FIG. 1, an image input device 505 (generally an image scanner) and an image forming unit (300) are connected directly or via an image processing device inside a copying machine.

The copying process is started by taking in an image with the image scanner 505,
The image data is input to the image forming unit 300 through the path 4 and the image formation is completed. On the other hand, in the case of a printer, this image input is not specified. Directly, the PC 506 in FIG.
It is common sense to determine that the connection is made through the path 501 due to, for example, the image data to the PC 506 may be input from the image scanner 505 through the path of 502, Other PC50
7 or disk (floppy disk, CD-ROM, T
ape, the Internet, etc.).

In the copying machine, illegal copying (illegal printing,
The method for preventing (duplication) is as follows. As shown in FIG. 12, using the data obtained by the image scanner unit 505, it is determined whether the image is a copy prohibited image. The determination unit 511 inputs data through the route 512 and makes a determination. Of course, 511 may be arranged on 504.
The determination result may be returned to 504 or may be returned to the image forming unit via the path 513.

Here, the principle of image formation and copying will be considered again with reference to FIG. The original 521 is converted into electronic data 522 by the image scanner 505 and
Sent to 0. In the image forming section, as described in the color printer, an exposure and development process is performed for each process color to form an image. Reference numerals 523 to 526 denote images for each process color. These images are superimposed on the intermediate transfer belt 320 and fixed by the fixing device 340 to obtain an image similar to the document 521.

Here, the copy-inhibited image judging section 51 shown in FIG.
A method for preventing unauthorized image formation using the determination result of No. 1 will be described. Here, the case of blocking by the image forming unit 300 will be described, but the same can be applied to the case of blocking along the route 514. The data obtained by the image scanner 505 is usually optical RGB data, and recognition processing is performed using the data. In the image forming unit 300, RGB
The image is formed by converting the data into process color data YMCK. Since the exposure / development process is performed for each process color, the conversion / exposure / development process is performed four times.

The recognition result can be reliably fed back during these four processes. For example, it is assumed that inhibition is performed in the fourth conversion, exposure, and development processes. That is, in this example, the process of uniformly painting the data 531 in FIG. 14 with the process color in this case is performed. As a result, the output printed matter 532 is the original 5
21 and printing can be illegally prevented.

As described above, in the color copier, since image scanning to image formation is performed consistently, both the image input unit 505 and the image forming unit 300 are used to appropriately prevent illegal image formation. It is possible. On the other hand, in a printer having only an image forming unit, there is a problem of where to obtain image data to be recognized and how to prevent image formation.

Next, a method of preventing output in a color printer will be described. In the copying machine, since the recognition process was performed using the data of the scanner unit, it was possible to perform the filling process at the stage of exposing at 302 in FIG. With the recognition methods [1] to [3], the same blocking method as that of the copying machine can be performed. Recognition method [4]-
In [6], a blocking method similar to that of a copying machine is not impossible, but there is a possibility that a step of processing the data developed by YMCK again is required.

In the recognition methods [7] and [8], since data for exposure is used, the same method as in a copying machine cannot be used. Therefore, a new blocking method is proposed. In FIG. 2, a photosensitive drum cleaner 304 generally has a function of removing remaining toner after being transferred from the photosensitive drum 302 to the intermediate transfer belt 320. Therefore, without transferring the toner to the intermediate transfer belt 320, the toner is cleaned by the photosensitive drum cleaner 304, so that one or more colors of toner are lost and the image quality is deteriorated.
The remaining image after the transfer and fixing is a deteriorated image.

Alternatively, after exposure, development, and transfer of YMCK, exposure, development, and transfer of one or more colors are performed again. The exposure data at this time may be such that the screen is uniformly painted or other data. It is not necessary that the data is print data, and different data is preferable in terms of deteriorating image quality. Also in this case, the image subjected to the remaining steps is deteriorated. Image formation similar to the blocking method in a copying machine can be obtained.

After the transfer to the intermediate transfer belt 320, path 3
It is also effective to use the intermediate transfer belt cleaner 321 to remove one or more color toners without transferring the image to the sheet existing on the sheet 30. The same effect as the cleaning on the photosensitive drum can be obtained. The same applies to FIG. 3 of the transfer drum system. The image developed on the photosensitive drum 1302 is
A method of removing with the cleaner of No. 04 is possible.

A cleaner 1321 for cleaning the transfer drum 1320 is also provided. Normally, when printing on paper, toner does not adhere to the transfer drum itself. This is because the image is transferred to the sheet on the transfer drum. However, the transfer drum may be transferred to the transfer drum itself in a test or the like, and the transfer drum can be cleaned in consideration of the case where the transfer drum becomes dirty due to a jam or the like. There is also a method to use this. That is, the toner of one or more colors transferred onto the paper is
321 scrapes it off.

Further, similarly to the intermediate transfer belt system, it is effective to perform exposure, development and transfer of one or more colors again.

[0056]

According to the present invention, unauthorized copying is recognized in the process of forming captured image data, and development on the image forming body is removed in response to the unauthorized recognition to prevent unauthorized copying. Therefore, illegal copying can be prevented not only in a copier in which a scanner and a printer are integrated, but also in an image forming apparatus that captures copy image data from an external scanner or a personal computer, and in a copying system equipped with the same. it can.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of a device configuration of a system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a basic configuration of a color printer used in the system of the embodiment.

FIG. 3 is a diagram showing a basic configuration of another color printer used in the system of the embodiment.

FIG. 4 is a block diagram showing an internal configuration of an internal image processing block of the color printer shown in FIG.

FIG. 5 is a diagram for explaining area gradation in gradation processing in a color printer.

FIG. 6 is a diagram for explaining PWM (pulse width modulation) in a color printer.

FIG. 7 is a diagram illustrating an example of a method of recognizing unauthorized copying in the system of the embodiment.

FIG. 8 is a diagram for explaining an example of a method for recognizing unauthorized copying in the system of the embodiment, together with FIG.

FIG. 9 is a diagram illustrating another method of recognizing unauthorized copying in the system of the embodiment.

FIG. 10 is a diagram illustrating still another method of recognizing unauthorized copying in the system of the embodiment.

FIG. 11 is a diagram illustrating still another method of recognizing unauthorized copying in the system of the embodiment.

FIG. 12 is a diagram illustrating an outline of a device configuration of a system according to another embodiment.

FIG. 13 is a diagram schematically illustrating a process of reading an original with a scanner and forming an image by the system according to the embodiment.

FIG. 14 is a diagram schematically illustrating a process of reading an original with a scanner and forming an image using the system of the embodiment according to another example.

[Explanation of symbols]

 300 color laser printer 350 internal image processing block 302 photosensitive drum 304 photosensitive drum cleaner 320 intermediate transfer belt 321 intermediate transfer belt cleaner

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 1/40 H04N 1/40 Z

Claims (8)

[Claims] An image forming apparatus which takes in image data of an electrophotographic system and outputs the image data by a printer, in an image forming process, an illegal copy recognizing means for recognizing whether or not to prohibit the image output. And an unauthorized copying preventing means for removing development of one or more colors on the image forming body in response to unauthorized recognition of the means. 2. The unauthorized copy preventing means removes development of one or more colors and adds an exposure / development / transfer process of one or more colors in response to unauthorized recognition of the unauthorized copy recognition means. The image forming apparatus according to claim 1, wherein: 3. The image forming apparatus according to claim 1, wherein said unauthorized copy recognizing means is means for recognizing the image data by using data when rasterizing the image data into raster data. 4. An image forming apparatus according to claim 3, wherein when the data is not divided raster data but data divided into areas, the recognition of copy prohibition is performed using raster data for each area. apparatus. 5. The image forming apparatus according to claim 4, wherein the recognition operation is not performed when the raster data expands the character data, and the recognition of the illegal copying is performed only when the image data is expanded. 6. The image forming apparatus according to claim 1, wherein said unauthorized copy recognizing means has means for storing a recognition result for each color of YMCK. 7. A method for preventing unauthorized copying of an image forming apparatus in which image data of an electrophotographic system is taken into an image processing section, and an image is formed and output by a printer. Determining whether or not the image forming apparatus is unauthorized, and recognizing the unauthorized copy; removing the development of one or more colors on the image forming body in response to the recognition of the unauthorized copy; Prevention method. 8. The method according to claim 7, wherein exposure, development, and transfer of one or more colors are performed in addition to removal of the development of one or more colors.