JP4595358B2 - Image processing apparatus and program - Google Patents

Description

  The present invention relates to a technique for embedding dots arranged to represent certain information in an image formed on a recording material.

  Image forming devices such as color printers and color copiers have improved image quality significantly, and recently, it is possible to reproduce complex patterns on banknotes and securities, etc., indistinguishable from real ones. . In fact, there are occasional cases where these valuables are counterfeited and misused.

Conventionally, the following mechanism has been proposed for this type of problem.
An image forming apparatus has an arrangement pattern that represents attribute information (for example, an image forming apparatus manufacturer name, an apparatus name, or an image forming date / time) for an image formed by the image forming apparatus. Embedded so that it is not visible to human eyes. When the counterfeit fact is discovered, the dot arrangement pattern included in the counterfeit image is analyzed to identify the image forming apparatus used for counterfeiting, the counterfeit date and time, and the like. Track the origin of counterfeit images. For example, in Patent Document 1, as an improvement measure for such a mechanism, the dot size and the like are adjusted as necessary so that the dots are not as noticeable as possible and the dot arrangement pattern is easily recognized when forgery is detected. Techniques for doing this are described.

JP 2003-234886 A

  By the way, the image forming apparatus cannot determine by itself what kind of image is copied for the purpose of counterfeiting. Therefore, basically, the dot as described above is applied to every image formed by the apparatus itself. It is designed to be embedded. In other words, an image is formed rarely for the purpose of counterfeiting, but the tracking dots as described above are always embedded in the image. However, from the viewpoint of not consuming toner wastefully, it is most desirable to embed dots in an image only when necessary.

  Accordingly, an object of the present invention is to provide a technique for efficiently embedding the dots as described above without consuming wasteful materials for forming an image such as toner.

To solve the above problems, the present invention includes an attribute information acquisition means for acquiring attribute information representing an attribute of the image forming process performed by the image forming means, the attribute information acquired by the attribute information obtaining unit table to, a pattern generating means for generating a placement pattern of the dot and the back surface of the recording material is already used in the case where the image is formed on the back surface of the recording material on which an image is formed based on the image data by said image forming means A determination unit that determines that the back surface of the recording material is not used when an image is not formed on the back surface of the recording material, and a determination unit that determines that the recording material is not used by the determination unit. embeds dot in accordance with the arrangement pattern generated by said pattern generating means to said image data, image based on the image data embedded with the dot While the formation to the image forming means, when it is determined that the already used by said determination means, instead of embedding the dot on the image data, an image based on the image data in which the dot is not embedded An image processing apparatus is provided that includes a control unit that causes the image forming unit to form the image processing unit.

  According to this image processing apparatus, when it is determined that the back surface of the recording material is not used, the dots are embedded in the image data according to the arrangement pattern, and when it is determined that the recording material has been used, the dots are embedded in the image. Do not embed in data. If the back side of the recording material has been used, there is a high possibility that the image formation process is not forgery. Therefore, avoid such a situation that dots are embedded in the image and toner is wasted. Can do. The attribute information indicating the attribute of the image forming process is, for example, identification information for specifying the manufacturer that manufactured the image forming means, identification information for specifying the image forming means, image forming means or This is identification information of an apparatus that has given an image formation instruction to the image forming unit, information indicating when an image formation process has been performed, and the like.

In a preferred aspect of the present invention, the determination unit includes a sensor that detects whether an image is formed on the recording material, and is provided on a back surface of the recording material on which the image is formed by the image forming unit. When the sensor detects that an image is formed, it determines that the back surface of the recording material has been used, and when the sensor detects that no image is formed on the back surface, the recording material. You may make it judge that the back surface of is not used .

Further, the present invention causes a computer, the attribute information acquisition function of acquiring the attribute information indicating the attribute of the image forming process performed by the image forming means, the attribute information acquired by the attribute information acquisition function table to, Dots A pattern generation function for generating an arrangement pattern of the image, and when an image is formed on the back surface of the recording material on which an image based on image data is formed by the image forming means, the back surface of the recording material is used And when the image is not formed on the back surface of the recording material, the determination function for determining that the back surface of the recording material is not used, and when the determination function determines that the recording material is not used, embedded dots in accordance with the arrangement pattern generated by the pattern generation function to the image data, the image based on the image data embedded with the dot While the formation to the image forming unit, wherein when it is determined that already used by decision function, instead of embedding the dot on the image data, wherein an image based on the image data in which the dot is not embedded A program for realizing a control function to be formed by an image forming unit is provided.

Embodiments of the present invention will be described below.
FIG. 1 is a diagram illustrating an overall configuration of an image forming apparatus 100 according to the embodiment. As shown in FIG. 1, the configuration of the image forming apparatus 100 is roughly divided into an image forming unit 10, an image reading unit 20, and a paper supply unit 30. In addition to the two types of paper supply sources, that is, the paper trays 31a, 31b, 31c and the manual feed tray 32, the paper supply unit 30 forms an image from these paper supply sources via a conveyance path indicated by a dotted line S in the figure. Conveying rollers 34 a to 34 c and a registration roller 34 d for conveying paper to the unit 10 are provided.

  The paper trays 31a and 31b contain a plurality of sheets P1 and P2 having different sizes. The paper tray 31c accommodates a used paper P3 that is the same size as the paper P2 but has already been used on the back surface. This paper P3 is intended to save paper consumption, and is used for applications in which separate images that are completely unrelated to the back surface and the front surface may be formed. This paper P3 is generally called “back paper”. These sheets P1, P2, and P3 are sent out one by one to the conveyance path S by sheet feed rolls 311a, 311b, and 311c provided on the respective sheet trays 31a, 31b, and 31c. A plurality of sheets P4 are placed on the upper surface of the manual feed tray 32, and these sheets P4 are sent one by one to the transport path S by the sheet feed roller 321.

  The image reading unit 20 includes a document feeder 21 and an optical system member 22 composed of a CCD (Charge Coupled Device) or the like, and reads an image with a CCD of a document placed on a platen glass (not shown). Then, image data representing the read image is generated. The image forming apparatus 100 is connected to a network such as a local area network (LAN) via a driver (not shown), and receives image data transmitted from a host device such as a personal computer or a server machine via the LAN. Receive. The image forming unit 10 performs image forming processing based on image data generated by the image reading unit 10 or image data received via a driver.

  The image forming unit 10 includes a photosensitive drum 11 that rotates in the direction of arrow b in the figure, a charger 12 that uniformly charges the surface of the photosensitive drum 11, and yellow (Y), magenta (M), and cyan. (C) An exposure device 13 that irradiates the photosensitive drum 11 with laser light modulated based on image data of each color of black (K) and forms an electrostatic latent image of each color of YMCK on the surface thereof; A rotary developer 14 that develops the electrostatic latent image formed on the drum 11 with toner of each color of YMCK to form a toner image, and a drum that collects toner remaining on the surface of the photosensitive drum 11 after the primary transfer And a cleaner 15.

  Further, the image forming unit 10 includes an intermediate transfer belt 16 for primary transfer of a toner image formed on the surface of the photosensitive drum 11. The intermediate transfer belt 16 is an endless belt member, and is stretched by a plurality of rolls such as a drive roll 17, a primary transfer roll 18, and a secondary transfer roll 19, and the arrow in FIG. Circulated in the c direction. The primary transfer roll 18 forms a nip region with the photosensitive drum 11 with the intermediate transfer belt 16 interposed therebetween. In this nip region, the toner image on the surface of the photosensitive drum 11 is primarily transferred onto the surface of the intermediate transfer belt 16. The toner image primarily transferred to the intermediate transfer belt 16 is secondarily transferred to a sheet as an image in a nip region formed by the secondary transfer roll 19 and the backup roll 40. Then, the sheet on which the image is secondarily transferred is conveyed to the fixing device 41, subjected to fixing processing, and discharged to the paper discharge tray 42. The toner remaining on the surface of the intermediate transfer belt 16 after the primary transfer is removed by the belt cleaner 23.

  Further, the image forming apparatus 100 includes a user interface device 50 for the user to perform various operations. The user interface device 50 includes a liquid crystal display that functions as a touch panel, and the user can perform various operations by touching the liquid crystal display. For example, the user provides paper information such as the size and type of the papers P1, P2, P3, and P4 stored in the paper trays 31a, 31b, and 31c and the manual feed tray 32, and whether or not the paper is back paper. The interface device 50 can be operated and input to the image forming apparatus 100.

  Next, FIG. 2 is a block diagram illustrating a configuration for performing image processing in the image forming apparatus 100. As illustrated in FIG. 2, the image forming apparatus 100 includes an image processing unit 211 and a unit controller 212 that controls the image forming unit 10 based on image data supplied by the image processing unit 211. The image processing unit 211 and the unit controller 212 function as an image processing apparatus that performs image processing and instructs the image forming unit 10 to perform image forming processing.

The image processing unit 211 includes a decoder 202, a band memory A 203, a band memory B 204, a color conversion processing unit 205, a γ correction unit 206, and a halftone processing unit 207.
When the image forming apparatus 100 receives image data expressed in a page description language together with a print command from the host apparatus, the image data is first input from the driver 201 to the image processing unit 211. The driver 201 also receives attribute information (hereinafter referred to as host information) related to the host device that issued the print command from the host device, and stores it in the host information storage unit 213 in the image processing unit 211. In addition, in the print command, the content of the instruction as to which image forming process should be performed using the paper stored in which recording paper supply source (paper trays 31a, 31b, 31c or manual feed tray 32) of the image forming apparatus 100 The driver 201 stores the contents of this print command in the paper information storage unit 214. Further, the paper information previously input to the user interface device 50 by the user is supplied to the paper information storage unit 214 in the image processing unit 211 and stored in the paper information storage unit 214.

  The image data input to the image processing unit 211 is interpreted by the decoder 202 and converted into 8-bit image data of R, G, and B colors. Next, these RGB image data are input to the band memory. The band memory is composed of two memories, a band memory A203 and a band memory B204, and one memory can store image data for several lines. First, image data for RGB is output from the band memory A203 while the image area for the first predetermined line is expanded to the band memory A203 and the image area for the next predetermined number of lines is expanded to the band memory B204. Is done. Further, while the image area for the next predetermined number of lines is developed in the band memory A203, the image data is alternately stored in the two band memories, such as the RGB image data is output from the band memory B204. Expanded and output.

  The RGB image data output from the band memory is input to the color conversion processing unit 205, subjected to predetermined color conversion processing and UCR processing, and converted into M, C, Y, and K image signals. Since the image forming apparatus 100 separately forms images of each color of Y, M, C, and K, the color conversion processing unit 205 receives data for one page of M paper, data for one page of C paper, Y The image data is output in the order of data for one page of paper and data for one page of K paper. Further, the color conversion processing unit 205 sends color designation data indicating the currently output color to the unit controller 212.

  The image data of each color output from the color conversion processing unit 205 is then subjected to γ correction processing by the γ correction unit 206 so that the output density curve is optimized, and the halftone processing unit 207 performs systematic dithering and error. Halftone processing is performed by a technique such as a diffusion method. Thereafter, the image data input from the halftone processing unit 207 to the unit controller 212 is first input to the dot pattern addition processing unit 208.

In the dot pattern addition processing unit 208, dots are embedded in the image data input to the unit controller 212.
Here, the dot addition processing in the present embodiment will be described in detail. In this embodiment, Y (yellow) micro dots are arranged in an image according to a certain rule, and the attribute information of the image forming process is represented by the arrangement pattern of the dots. This attribute information includes, for example, a “manufacturer ID” for specifying the manufacturer of the image forming apparatus 100, a “device ID” such as a serial number for specifying the image forming apparatus 100, and the image forming apparatus or host apparatus. “Network ID” such as a network address, “date and time information” indicating the date and time when the image forming process was performed, and the like. Among these pieces of attribute information, “network ID” and “date / time information” are included in the host information supplied from the host device to the image processing unit 211 and stored in the host information storage unit 213. . On the other hand, “maker ID” and “apparatus ID” are stored in advance by the dot pattern addition processing unit 208 as apparatus information indicating the attributes of the image forming apparatus 100 itself.

  FIG. 3 is a schematic diagram illustrating an example of a dot arrangement pattern. In FIG. 3, various attribute information as described above is represented by the mutual positional relationship of dots d arranged at a plurality of locations in an image. FIG. 3 shows the minimum unit of the dot arrangement pattern. Actually, this minimum unit is repeatedly formed in the vertical direction (sub-scanning direction) and the horizontal direction (main scanning direction) over the entire image. Hereinafter, this minimum unit is referred to as a reference dot pattern p.

  As shown in FIG. 3, the reference dot pattern p of the present embodiment is composed of four areas: a start mark area A1, a manufacturer ID area A2, a device ID area A3, and other information areas A4. The manufacturer ID area A2 is an area where dots representing manufacturer IDs are arranged, the device ID area A3 is an area where dots representing device IDs are arranged, and the other information area A4 is a network ID and date / time information. This is an area in which dots representing The start mark area A1 is an area indicating the start of the reference dot pattern p. In this start mark area A1, dots are arranged in a predetermined pattern. When the attribute information is decoded, first, the start mark area A1 is detected to determine the start, direction and range of the reference dot pattern p. Can be identified.

The paper information storage unit 214 determines whether the paper on which the image is to be formed is a backing paper based on the paper information stored in itself and the content of the print command, and the determination result is sent to the dot pattern addition processing unit 208. Notice. When the dot pattern addition processing unit 208 is notified from the paper information storage unit 214 that the paper on which the image is to be formed is not the back paper, the dot pattern addition processing unit 208 determines that the dot representing the attribute information as described above should be embedded in the image data. If it is notified that it is a backing paper, it is determined that the dot representing the attribute information is not embedded in the image data. The reason is as follows.
If the paper is a back paper, the possibility of forming an image for counterfeiting should be extremely low. This is because the back side of the paper already has an image that has nothing to do with the image forming process to be performed. This is because it cannot be used. Of course, it is not impossible at all to copy only one side of a bill or the like on the back side of the paper first, and then duplicate the other side of the bill or the like on the front side of the paper. It is necessary to very accurately align the images on the front and back sides of the paper. However, such an accurate alignment is very difficult in an image forming apparatus currently on the market. Therefore, many counterfeit tricks include duplicating one side and the other side of a bill or the like on separate papers and sticking them together exactly.

  Accordingly, when the paper on which the image is formed is not the backing paper, the dot pattern addition processing unit 208 generates a dot arrangement pattern that represents the above attribute information, and the dot of such arrangement pattern is converted into image data. And is supplied to the PWM processing unit 209. On the other hand, when the paper on which an image is to be formed is a backing paper, the dot pattern addition processing unit 208 does not embed dots in the image data, but directly uses the image data supplied from the halftone processing unit 207 as a PWM processing unit. 209. The PWM processing unit 209 performs pulse width modulation on the image data, and further performs D / A conversion, and then inputs it to the laser driving unit 210 as a driving signal. The laser driving unit 210 drives and controls the exposure device 13 based on the input driving signal, and irradiates the photosensitive drum 11 with laser light. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 11.

Next, the configuration of the dot pattern addition processing unit 208 will be described in more detail.
FIG. 4 is a block diagram showing the configuration of the dot pattern addition processing unit 208. In a ROM (Read Only Memory) 702, an 8-bit manufacturer ID and a 16-bit device ID of the image forming apparatus 100 are stored in advance as device information of the image forming apparatus 100. A CPU (Central Processing Unit) 701 acquires a manufacturer ID and a device ID (that is, device information) from the ROM 702 during image formation, and stores them in a register 703 in the CPU 701. In addition, the CPU 701 acquires a network ID and date / time information (that is, host information) from the host information storage unit 213 and stores it in the register 703. The device information and host information (that is, attribute information) stored in the register 703 is encrypted by the CPU 701, converted into position information of each dot to be arranged in the reference dot pattern p, and stored again in the register 703. Is done.

  Further, the CPU 701 stores the contents notified from the paper information storage unit 214 in the register 703. When the notification content stored in the register 703 indicates “the paper is not the back paper”, the CPU 701 instructs the addition designation processing unit 706 described later to add a dot, while the content stored in the register 703 When “Indicates that the paper is a backing paper”, the addition designation processing unit 706 is not instructed to add dots.

  The main scanning counter 704 performs a counting operation according to the clock signal VCLK in the main scanning direction of the image signal, and notifies the additional designation processing unit 706 of the count number in the main scanning direction. The sub-scanning counter 705 performs a counting operation according to the sub-scanning direction clock signal LCLK, and notifies the additional designation processing unit 706 of the count number in the sub-scanning direction. The addition designation processing unit 706 is stored in the register 703 only when the color designation data notified from the color conversion processing unit 205 designates yellow and the CPU 701 instructs to add a dot. The additional designation data is output to the signal conversion unit 707 at the timing when the dot is to be added with reference to the position information of the dot, the count in the main scanning direction, and the count in the sub-scanning direction. When the additional designation data is supplied, the signal converter 707 superimposes image data representing dots on the input image data. By performing such processing, the dot pattern addition processing unit 208 generates image data to be supplied to the PWM processing unit 209.

  As described above, according to the present embodiment, there is a high possibility that the image forming process is not forgery when the back side of the paper is used like the back paper. Do not embed images. As a result, toner consumption can be saved.

In addition, this invention is not limited to embodiment mentioned above, Various deformation | transformation as shown below are possible.
In the embodiment, it is determined whether or not the back side of the paper has been used based on the paper information input in advance by the user. However, the present invention is not limited to this. For example, a back paper detection sensor for detecting whether or not an image is formed on the paper is provided, and it is determined whether the back side of the paper has been used based on an output signal from the back paper detection sensor. May be. Whether or not an image (toner image) is formed on the paper is only required to detect whether or not there is a toner component on the paper. Therefore, the back paper detection sensor uses a photodiode or a CCD, for example. Any sensor that detects the presence or absence may be used.

  Such a back paper detection sensor is used for the paper P1, which is placed on the top of the paper trays 31a, 31b, and 31c in FIG. It is desirable that the detection surface is disposed with the detection surface facing from the lower side of the leading end of the conveyance direction of P2 and P3 to the back surface of the sheet. FIG. 5 shows the configuration of the image forming apparatus in this case. In FIG. 5, the driver 201 issues a print command as to which recording paper supply source (paper trays 31 a, 31 b, 31 c or manual feed tray 32) of the image forming apparatus 100 should perform image forming processing. Based on the content of the above, a signal instructing to perform sensing is output to the back paper detection sensor 215 provided in the paper tray to be used. In response to this, the backing paper detection sensor 215 starts sensing and supplies an output signal indicating the presence or absence of toner to the dot pattern addition processing unit 208. The dot pattern addition processing unit 208 determines whether the paper on which an image is formed is a back paper based on an output signal from the back paper detection sensor 215. If it is determined that the paper is not a back paper, A dot arrangement pattern representing the attribute information is generated, added to the image data, and supplied to the PWM processing unit 209. On the other hand, when the dot pattern addition processing unit 208 determines that the paper is the back paper based on the output signal from the back paper detection sensor 215, the dot pattern addition processing unit 208 is supplied from the halftone processing unit 207 without adding dots to the image data. The obtained image data is supplied to the PWM processing unit 209 as it is. The PWM processing unit 209 performs pulse width modulation on the image data, performs D / A conversion, and inputs it to the laser driving unit 210 as a driving signal. The laser driving unit 210 drives and controls the exposure device 13 based on the input driving signal to irradiate the photosensitive drum 11 with laser light. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 11.

  Note that just because the user inputs paper information “back paper”, an image (toner image) is not always formed on the back side of the paper. This is because, depending on the user, when a memo is written on the back side of the paper with a pen or the paper is soiled, the paper may be stored in the paper tray as a back paper. In other words, the back side of the paper has been used. In addition to the case where an image (toner image) is formed on the back side of the paper, the back side cannot be used for some reason as described above. Such cases are also included.

  In the embodiment, a so-called cycle system and an image forming apparatus including a photosensitive drum and a rotary developing device as a latent image carrier have been described. It may be a so-called tandem type image forming apparatus arranged in series. Further, the image forming apparatus is not limited to an apparatus that forms a YMCK color image.

  In the embodiment, the paper is described as an example of the recording material to which the toner image is transferred. However, various recording materials such as plastic such as an OHP film and cloth can be used. .

  Further, the reference dot pattern p is divided into the start mark area, the manufacturer ID area, the device ID area, and other information areas. However, the method of dividing the area and the information represented by the dots arranged in each area are limited to the contents described in the embodiment. Absent. Further, the number of bits of information to be added is not limited to that described in the embodiment.

  Note that the dot addition processing of this embodiment can also be executed by the CPU of the host device, for example. In this case, programs executed by the CPU include a magnetic tape, a magnetic disk, a floppy (registered trademark) disk, an optical recording medium, a magneto-optical recording medium, a CD (Compact Disk) -ROM, a DVD (Digital Versatile Disk), a RAM, and the like. It can be provided in a state of being recorded on the recording medium.

1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. 2 is a diagram illustrating a configuration of an image processing system of the image forming apparatus. FIG. It is a schematic diagram which shows an example of the reference | standard dot pattern formed on a paper. 2 is a block diagram illustrating a configuration of a dot pattern addition processing unit of the image forming apparatus. FIG. FIG. 10 is a block diagram illustrating a configuration of an image processing system of an image forming apparatus according to a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Image forming apparatus, 10 ... Image forming unit, 20 ... Image reading unit, 30 ... Paper supply unit, 31a, 31b, 31c ... Paper tray, 50 ... User interface device 208, dot pattern addition processing unit, 211, image processing unit, 212, unit controller, 213, host information storage unit, 214, paper information storage unit.

Claims (3)

Attribute information acquisition means for acquiring attribute information representing attributes of image formation processing performed by the image forming means;
The attribute information table to the acquired attribute information by the acquisition unit, a pattern generating means for generating a placement pattern of the dot and
When an image is formed on the back surface of the recording material on which an image based on image data is formed by the image forming means, it is determined that the back surface of the recording material is used, and an image is formed on the back surface of the recording material. A judging means for judging that the back surface of the recording material is not used when it is not formed;
If it is determined by the determining means that the image has not been used , dots are embedded in the image data according to the arrangement pattern generated by the pattern generating means, and an image based on the image data in which the dots are embedded is displayed on the image forming means while the formation, in the case it is determined that the already used by said determination means, instead of embedding the dot on the image data, an image based on the image data in which the dot is not embedded in the image forming unit the image processing apparatus and a control means for forming. The determination means includes
It has a sensor that detects whether an image is formed on the recording material,
When the sensor detects that an image is formed on the back surface of the recording material on which an image is formed by the image forming means, the back surface of the recording material is determined to be used, and an image is formed on the back surface. The image processing apparatus according to claim 1, wherein when the sensor detects that the recording material is not used, the rear surface of the recording material is determined not to be used. On the computer,
An attribute information acquisition function for acquiring attribute information representing an attribute of image forming processing performed by the image forming unit;
The attribute information acquired by the attribute information obtaining function and a pattern generation function of generating a table to, the Dots arrangement pattern,
When an image is formed on the back surface of the recording material on which an image based on image data is formed by the image forming means, it is determined that the back surface of the recording material is used, and an image is formed on the back surface of the recording material. A determination function for determining that the back surface of the recording material is not used when it is not formed;
If it is determined by the determination function that it has not been used , dots are embedded in the image data in accordance with the arrangement pattern generated by the pattern generation function, and an image based on the image data in which the dots are embedded while the formation, in the case it is determined that the already used by the determination function, instead of embedding the dot on the image data, an image based on the image data in which the dot is not embedded in the image forming unit A program for realizing the control functions to be formed .

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