JP3773653B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a digital color copying machine that reads a color image on a document and forms a duplicate image thereof.
[0002]
[Prior art]
In recent years, image quality of image forming devices such as scanners, printers, and electronic copiers has been greatly improved in reproducibility, and banknotes and securities that should not be reproduced can be easily reproduced. There is a concern that it will be played back with high image quality that cannot be distinguished from this, and that this will be abused.
[0003]
Along with this, forgery such as discriminating whether the image is a specific manuscript such as banknotes or securities, and prohibiting the image reproduction operation when it is determined that the image is a specific manuscript such as banknotes or securities. Prevention technology is essential.
[0004]
Further, even if the above-described anti-counterfeiting technology is fully utilized, the effect of anti-counterfeiting is not perfect, and it is possible that a specific manuscript such as banknotes or securities that should not be reproduced is actually reproduced. .
[0005]
Therefore, even if specific documents such as banknotes and securities that should not be reproduced are reproduced, images of specific documents that must not be reproduced such as banknotes and securities so that the image forming apparatus can be identified from the reproduced image. There is a technique for adding a specific pattern unique to the machine body to a reproduced image that can identify an image forming apparatus using a specific color that is difficult to identify with the naked eye, such as yellow colorant, for all reproduced images. For example, it is known from JP-A-4-294682.
[0006]
On the other hand, in an image forming apparatus in which the scanner unit and the printer unit can be separated and an image forming apparatus having an interface capable of inputting / outputting images to / from an external device, the work is performed via the image input / output interface. A technique for preventing counterfeiting of a specific manuscript that should not be reproduced, such as banknotes and securities, even when an image is formed by an external image forming apparatus connected to a station or the like is disclosed in, for example, Japanese Patent Laid-Open No. 7-336533 Is known by.
[0007]
[Problems to be solved by the invention]
With the conventional technique for determining a specific manuscript, it is difficult to accurately determine a specific manuscript that should not be reproduced, such as banknotes and securities, without making a misjudgment, and the technique disclosed in Japanese Patent Laid-Open No. 7-336533 is used. However, banknotes and securities that should not be regenerated can be regenerated using an external image forming device that does not have an anti-counterfeit function by connecting to an external workstation via an image input / output interface. It can happen.
[0008]
Therefore, the present invention can prevent forgery of a specific document even when image data read from a document is output to an external device, and when image data for forming a duplicate image is input from another external device. However, it is an object of the present invention to provide an image forming apparatus that can prevent abuse of a duplicate image.
[0009]
[Means for Solving the Problems]
The image forming apparatus of the present invention reads an image from a document, Separated into red, green and blue Image reading means for outputting image data; Input processing means for inputting image data that has been color-separated into red, green, and blue output from the image reading means, and red, green, and blue output from the input processing means Specific document determination means for determining whether the image data is a specific document set in advance; Color conversion means for converting red, green, and blue image data output from the input processing means into cyan, magenta, yellow, and black image data, and cyan, magenta, yellow, and black output from the color conversion means First image processing means for performing image processing for anti-counterfeiting and output from the first image processing means when image processing of the image data is performed and the specific original determination means determines that the original is a specific original First specific pattern adding means for adding a specific pattern to the yellow image data to be processed, yellow image data to which the specific pattern output from the first specific pattern adding means is added, and the first Image output interface means for outputting cyan, magenta, yellow, and black image data output from the image processing means to the outside; From outside Cyan, magenta, yellow, black Image input interface means for inputting the image data of the image, and input from the image input interface means Selection means for selecting one of cyan, magenta, yellow, and black image data, or cyan, magenta, yellow, and black image data output from the first image processing means, and the selection means. Second image processing means for performing image processing of cyan, magenta, yellow, and black image data, and performing image processing for preventing forgery when the specific original determination means determines that the original is a specific original; this Second Output from image processing means Yellow A unique specific pattern for identifying the image forming apparatus is added to the image data. Second Specific pattern adding means and this Second Image data with a specific pattern added by a specific pattern adding means And cyan, magenta, and black image data output from the second image processing means; And image forming means for forming an image on a recording medium.
[0011]
Furthermore, the image forming apparatus of the present invention reads an image from a document, Separated into red, green and blue Image reading means for outputting image data; Input processing means for inputting image data that has been color-separated into red, green, and blue output from the image reading means, and red, green, and blue output from the input processing means Specific document determination means for determining whether the image data is a specific document set in advance; Color conversion means for converting red, green, and blue image data output from the input processing means into cyan, magenta, yellow, and black image data, and cyan, magenta, yellow, and black output from the color conversion means Image processing is performed, and if the specific document determination unit determines that the document is a specific document, image processing for forgery prevention is performed. First image processing means and externally Cyan, magenta, yellow, black Image input interface means for inputting the image data of the image, and input from the image input interface means First selection means for selecting any one of cyan, magenta, yellow, and black image data, or cyan, magenta, yellow, and black image data output from the first image processing means; Selected by the selection means A unique specific pattern for identifying the image forming apparatus is added to the image data of Specific pattern addition means When, Whether yellow image data to which a specific pattern is added by the specific pattern adding means and cyan, magenta, and black image data selected by the first selecting means are output to the outside or an image is formed. Second selection means to be selected, yellow image data to which a specific specific pattern is added by the specific pattern addition means when the second selection means is selected to output to the outside, and the first selection Selected cyan, magenta, and black image data Image output interface means for outputting to the outside, The yellow image data to which the specific pattern is added by the specific pattern adding unit and the cyan, magenta, and black selected by the first selecting unit when the second selection unit selects to form an image. Image data is processed, and if the specific document determining means determines that the document is a specific document, image processing for preventing forgery is performed. A second image processing means; Cyan, magenta, yellow, and black processed by the second image processing means Image forming means for forming an image on a recording medium based on the image data.
[0013]
In addition, by providing a specific pattern adding means before the image output interface means, a specific pattern can always be added to the image data output to the external device, and the printer does not have a specific pattern adding function. Even when an image is reproduced (duplicated) by the external device, since the specific pattern is already added to the image data itself, the abuse of the reproduced image (duplicated image) can be prevented.
[0014]
Further, when the specific pattern adding means is provided at a later stage than the image input interface means on the image forming means side, image data for forming a duplicate image is input from an external device via the image input interface means. However, a specific pattern can always be added, and abuse of a reproduced image (duplicated image) can be prevented.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 schematically shows an internal configuration of an image forming apparatus such as a digital color copying machine that reads a color image on a document and forms a duplicate image according to the present invention. This image forming apparatus is roughly divided into a color scanner unit 1 as an image reading unit for reading and inputting a color image on a document, and a color printer unit 2 as an image forming unit for forming a duplicate image of the input color image. It consists of and.
[0016]
The color scanner unit 1 has a document table cover 3 at the top thereof, and is disposed opposite to the document table cover 3 in a closed state, and has a document table 4 made of transparent glass on which a document is set. Below the document table 4, an exposure lamp 5 for illuminating the document placed on the document table 4, a reflector 6 for condensing the light from the exposure lamp 5 on the document, and reflected light from the document. A first mirror 7 that is bent leftward with respect to the drawing is disposed. The exposure lamp 5, the reflector 6, and the first mirror 7 are fixed to the first carriage 8. The first carriage 8 is translated along the lower surface of the document table 4 by being driven by a pulse motor (not shown) via a toothed belt (not shown).
[0017]
In the left side of the drawing with respect to the first carriage 8, that is, in the direction in which the light reflected by the first mirror 7 is guided, the document table is connected via a driving mechanism (not shown) (for example, a toothed belt and a DC motor). A second carriage 9 is provided so as to be movable in parallel with 4. The second carriage 9 includes a second mirror 11 that bends the reflected light from the document guided by the first mirror 7 downward in the figure, and a third mirror that bends the reflected light from the second mirror 11 rightward in the figure. The mirrors 12 are arranged at right angles to each other. The second carriage 9 is driven by the first carriage 8 and translated along the document table 4 at a speed of 1/2 with respect to the first carriage 8.
[0018]
An imaging lens 13 that forms an image of the reflected light from the third mirror 12 at a predetermined magnification is disposed in a plane including the optical axis of the light reflected by the second and third mirrors 11 and 12. A CCD color image sensor (photoelectric conversion element) 15 for converting the reflected light, which is focused by the imaging lens 13, into an electric signal is disposed in a plane substantially orthogonal to the optical axis of the light that has passed through the lens 13. It is installed.
[0019]
Thus, when the light from the exposure lamp 5 is condensed on the document on the document table 4 by the reflector 6, the reflected light from the document is reflected in the first mirror 7, the second mirror 11, the third mirror 12, and the connection. The light is incident on the color image sensor 15 through the image lens 13, and the incident light is converted into an electric signal corresponding to the three primary colors of R (red), G (green), and B (blue).
[0020]
The color printer unit 2 is an image that is color-separated for each color component based on a known subtractive color mixing method, that is, yellow (y), magenta (m), cyan (c), and black (k). The first to fourth image forming units 10y, 10m, 10c, and 10k that respectively form the four color images.
[0021]
Below each of the image forming units 10y, 10m, 10c, and 10k, there is a transport mechanism 20 including a transport belt 21 as a transport unit that transports an image of each color formed by each image forming unit in the direction of arrow a in the figure. It is arranged. The conveyor belt 21 is wound and stretched between a driving roller 91 that is rotated in the direction of arrow a by a motor (not shown) and a driven roller 92 that is separated from the driving roller 91 by a predetermined distance, and is constant in the direction of arrow a. Travel endlessly at speed. The image forming units 10y, 10m, 10c, and 10k are arranged in series along the conveyance direction of the conveyance belt 21.
[0022]
Each of the image forming units 10y, 10m, 10c, and 10k includes photosensitive drums 61y, 61m, 61c, and 61k as image carriers whose outer peripheral surfaces are formed so as to be rotatable in the same direction at positions where they contact the conveyor belt 21, respectively. Contains. Each of the photosensitive drums 61y, 61m, 61c, and 61k is rotated at a predetermined peripheral speed by a motor (not shown).
[0023]
The photosensitive drums 61y, 61m, 61c, and 61k are arranged so that the axes thereof are equally spaced from each other, and the axes are arranged to be orthogonal to the direction in which the image is conveyed by the conveyance belt 21. ing. In the following description, the axial direction of the photosensitive drums 61y, 61m, 61c, and 61k is the main scanning direction (second direction), and the rotational direction of the photosensitive drums 61y, 61m, 61c, and 61k, that is, The direction of rotation of the conveyor belt 21 (the direction of arrow a in the figure) is the sub-scanning direction (first direction).
[0024]
Around each of the photosensitive drums 61y, 61m, 61c, and 61k, charging devices 62y, 62m, 62c, and 62k as charging means extending in the main scanning direction, static eliminating devices 63y, 63m, 63c, and 63k, main scanning Developing rollers 64y, 64m, 64c, 64k as developing means extended in the same direction, lower stirring rollers 67y, 67m, 67c, 67k, upper stirring rollers 68y, 68m, 68c, 68k, similarly in the main scanning direction Transfer devices 93y, 93m, 93c, 93k as extended transfer means, cleaning blades 65y, 65m, 65c, 65k similarly extended in the main scanning direction, and waste toner collection screws 66y, 66m, 66c, 66k are arranged in order along the rotation direction of the photosensitive drums 61y, 61m, 61c, and 61k, respectively.
[0025]
Each of the transfer devices 93y, 93m, 93c, and 93k is disposed at a position where the conveyance belt 21 is sandwiched between the corresponding photosensitive drums 61y, 61m, 61c, and 61k, that is, inside the conveyance belt 21. ing. Further, exposure points by the exposure device 50 described later are on the outer peripheral surfaces of the photosensitive drums 61y, 61m, 61c, and 61k between the charging devices 62y, 62m, 62c, and 62k and the developing rollers 64y, 64m, 64c, and 64k, respectively. Formed.
[0026]
Below the transport mechanism 20, paper cassettes 22a and 22b containing a plurality of sheets P as image forming media (recording media) to which images formed by the image forming units 10y, 10m, 10c, and 10k are transferred. Is arranged.
[0027]
Pick-up rollers 23a and 23b for picking up the sheets P stored in the sheet cassettes 22a and 22b one by one from the uppermost part are disposed at one end of the sheet cassettes 22a and 22b and close to the driven roller 92. Has been. Between the pickup rollers 23a and 23b and the driven roller 92, the leading edge of the paper P taken out from the paper cassettes 22a and 22b and the leading edge of the y toner image formed on the photosensitive drum 61y of the image forming unit 10y are aligned. A registration roller 24 is provided for this purpose.
[0028]
The toner images formed on the other photosensitive drums 61y, 61m, and 61c are supplied to each transfer position in accordance with the conveyance timing of the paper P conveyed on the conveyance belt 21.
[0029]
The registration roller 24 is interposed between the registration roller 24 and the first image forming unit 10 y in the vicinity of the driven roller 92, that is, substantially on the outer periphery of the driven roller 92 with the conveyance belt 21 interposed therebetween. An attracting roller 26 is provided for applying an electrostatic attracting force to the paper P conveyed at a predetermined timing. The axis of the suction roller 26 and the axis of the driven roller 92 are set to be parallel to each other.
[0030]
In order to detect the position of the image formed on the conveyance belt 21 at one end of the conveyance belt 21 and in the vicinity of the drive roller 91, that is, substantially on the outer periphery of the drive roller 91 with the conveyance belt 21 interposed therebetween. The position deviation sensor 96 is disposed. The positional deviation sensor 96 is constituted by, for example, a transmissive or reflective optical sensor.
[0031]
A conveyor belt cleaning device 95 for removing toner adhering to the conveyor belt 21 or debris of the paper P on the conveyor belt 21 on the outer periphery of the driving roller 91 and downstream of the position deviation sensor 96. Is arranged.
[0032]
In the direction in which the paper P transported via the transport belt 21 is separated from the driving roller 91 and is transported, the toner image transferred to the paper P is melted by heating the paper P to a predetermined temperature, A fixing device 80 for fixing the toner image on the paper P is provided. The fixing device 80 includes a pair of heat rollers 81, oil application rollers 82 and 83, a web winding roller 84, a web roller 85, and a web pressing roller 86. The toner formed on the paper P is fixed on the paper and is discharged by the paper discharge roller pair 87.
[0033]
The exposure device 50 that forms electrostatically separated electrostatic latent images on the outer peripheral surfaces of the respective photosensitive drums 61y, 61m, 61c, and 61k has image data for each color that is color-separated by the image processing device 36 described later. A semiconductor laser oscillator 60 whose emission is controlled based on (Y, M, C, K) is provided. On the optical path of the semiconductor laser oscillator 60, the polygon mirror 51 rotated by the polygon motor 54 for reflecting and scanning the laser beam light, and the focus of the laser beam light reflected through the polygon mirror 51 are corrected and connected. Fθ lenses 52 and 53 for imaging are provided in order.
[0034]
Between the fθ lens 53 and the photosensitive drums 61y, 61m, 61c, and 61k, the laser beam light of each color that has passed through the fθ lens 53 is directed to the exposure positions of the photosensitive drums 61y, 61m, 61c, and 61k. First folding mirrors 55y, 55m, 55c, and 55k to be folded, and second and third folding mirrors 56y, 56m, and 56c to further fold the laser beam folded by the first folding mirrors 55y, 55m, and 55c. 57y, 57m, 57c are arranged.
[0035]
The laser beam light for black is turned back by the first turning mirror 55k and then guided to the photosensitive drum 61k without passing through another mirror.
[0036]
FIG. 2 is a block diagram schematically showing the flow of signals for electrical connection and control of the image forming apparatus shown in FIG. In FIG. 2, the control system is composed of three CPUs: a main CPU (central processing unit) 91 in the main control unit 30, a scanner CPU 100 of the color scanner unit 1, and a printer CPU 110 of the color printer unit 2. .
[0037]
The main CPU 91 performs bidirectional communication with the printer CPU 110 via a shared RAM (random access memory) 35. The main CPU 91 issues an operation instruction and the printer CPU 110 returns a status status. The printer CPU 110 and the scanner CPU 100 perform serial communication, the printer CPU 110 issues an operation instruction, and the scanner CPU 100 returns a status status.
[0038]
The operation panel 40 includes a liquid crystal display unit 42, various operation keys 43, and a panel CPU 41 to which these are connected, and is connected to the main CPU 91.
The main control unit 30 includes a main CPU 91, ROM (read only memory) 32, RAM 33, NVRAM 34, shared RAM 35, image processing device 36, page memory control unit 37, page memory 38, printer controller 39, and printer font ROM 121. It is constituted by.
[0039]
The main CPU 91 is responsible for overall control. The ROM 32 stores a control program and the like. The RAM 33 temporarily stores data.
[0040]
An NVRAM (non-volatile RAM) 34 is a non-volatile memory backed up by a battery (not shown), and retains stored data even when the power is shut off.
[0041]
The shared RAM 35 is used for bidirectional communication between the main CPU 91 and the printer CPU 110.
The page memory control unit 37 stores or reads out image information with respect to the page memory 38. The page memory 38 has an area where image information for a plurality of pages can be stored, and is formed so that data obtained by compressing image information from the color scanner unit 1 can be stored for each page.
[0042]
The printer font ROM 121 stores font data corresponding to print data. The printer controller 39 uses print data from an external device 122 such as a personal computer as image data using font data stored in the printer font ROM 121 at a resolution corresponding to the data indicating the resolution given to the print data. It expands to.
[0043]
The color scanner unit 1 moves a scanner CPU 100 for overall control, a ROM 101 for storing control programs, a RAM 102 for data storage, a CCD driver 103 for driving the color image sensor 15, the first carriage 8, and the like. The scanning motor driver 104 that controls the rotation of the scanning motor to be operated, the image correction unit 105, and the like.
[0044]
The image correction unit 105 is adapted to an A / D conversion circuit that converts R, G, and B analog signals output from the color image sensor 15 into digital signals, variations in the color image sensor 15, changes in ambient temperature, and the like. The shading correction circuit corrects the fluctuation of the threshold level with respect to the output signal from the color image sensor 15 and the line memory that temporarily stores the shading-corrected digital signal from the shading correction circuit.
[0045]
The color printer unit 2 includes a printer CPU 110 that performs overall control, a ROM 111 that stores control programs, a RAM 112 for storing data, a laser driver 113 that drives the semiconductor laser oscillator 60, and a polygon motor 54 of the exposure apparatus 50. A polygon motor driver 114 that drives the sheet P, a conveyance control unit 115 that controls conveyance of the paper P by the conveyance mechanism 20, the charging device, the developing roller, and the transfer device, and controls the process of charging, developing, and transferring. The process control unit 116 includes a fixing control unit 117 that controls the fixing device 80, an option control unit 118 that controls options, and the like.
[0046]
The image processing device 36, the page memory 38, the printer controller 39, the image correction unit 105, and the laser driver 113 are connected by an image data bus 120.
[0047]
FIG. 3 shows in detail the configuration of the image processing apparatus 36 according to the first embodiment. The image processing apparatus 36 includes an input processing unit 131 to which image data separated into red (R), green (G), and blue (B) is input from the color scanner unit 1, and an RGB image from the input processing unit 131. The specific document determination unit 132 as a specific document determination unit that determines a specific document using data, and RGB image data from the input processing unit 131 are cyan (C), magenta (M), yellow (Y), and black (K). The color conversion unit 133 serving as a color conversion unit for converting the data into the data of (2), normally, YMCK image data output from the color conversion unit 133 is subjected to processing such as enlargement, reduction, background removal, noise removal, and edge enhancement. First image processing means for performing image processing for anti-counterfeiting different from the normal image processing when a specific document determination signal output from the specific document determination unit 132 is input. Filter processing unit 134, first specific pattern adding unit 135 as first specific pattern adding means for adding a specific pattern to yellow (Y) image data output from filter processing unit 134, filter processing Image output interface 136 as image output interface means for outputting image data output from the unit 134 and the first specific pattern adding unit 135 to an external device, and YMCK for forming a duplicate image from an external device Image input interface 137 as image input interface means for inputting image data, YMCK image data output from filter processing unit 134, or YMCK image data input from image input interface 137 Selector section 138 as a selection means for selecting Normally, gradation correction or the like is performed on the YMCK image data selected by the selector unit 138, and a specific document determination signal output from the specific document determination unit 132 is input, which is different from the normal image processing. A second image processing unit 139 as second image processing means for performing image processing for forgery prevention, and a second pattern for adding a specific pattern to yellow (Y) image data output from the gradation processing unit 139 The second specific pattern adding unit 140 as specific pattern adding means is configured.
[0048]
FIG. 4 shows a first circuit configuration example that outputs an image processing result different from normal image processing inside the filter processing unit 134 and the gradation processing unit 139. This circuit includes a first image processing unit 151 that performs normal image processing as described above on input image data, and processing different from normal image processing on input image data, for example, data “0”. Alternatively, the second image processing unit 152 that performs a process of replacing “255” and a selector unit 153 that selects one of the outputs of the image processing units 151 and 152 are configured.
[0049]
That is, RGB image data is input to the image processing units 151 and 152, and a specific document determination signal output from the specific document determination unit 132 is input to the selector unit 153, so that the specific document determination signal is not a specific document “L In the case of “,” the image data subjected to the normal image processing by the first image processing unit 151 is selected by the selector unit 153 and output. On the other hand, when the specific document determination signal is “H” indicating a specific document, the image data replaced with “0” or “255” by the second image processing unit 152 is selected by the selector unit 153 and output.
[0050]
FIG. 5 shows a second circuit configuration example that outputs an image processing result different from normal image processing inside the filter processing unit 134 and the gradation processing unit 139. The circuit shown in FIG. 5A includes a register 154 having an initial value = 0, and an OR circuit (OR) 155 that takes the logical sum of the output of the register 154 and input image data. 5B includes a register 156 having an initial value = 255, and an AND circuit (AND) 157 that takes a logical product of the output of the register 156 and input image data.
[0051]
The initial values of the registers 154 and 156 are set by register settings from the main CPU 91 (or the scanner CPU 100 and the printer CPU 110).
[0052]
The operation of the circuit in FIG. 5A will be described. When the determination result of the specific document determination unit 132 is not a specific document, data “0” is set in the register 154 from the main CPU 91, and the OR circuit 155 outputs the register 154. And the input image data are output, and the input image data itself is output. On the other hand, when the determination result of the specific document determination unit 132 is a specific document, the data “255” is set in the register 154 from the main CPU 91, and the output of the register 154 in the OR circuit 155 and the logic of the input image data By taking the sum, the output becomes data “255” regardless of the input image data.
[0053]
The operation of the circuit in FIG. 5B will be described. When the determination result of the specific document determination unit 132 is not a specific document, data “255” is set in the register 156 from the main CPU 91, and the AND circuit 157 outputs the register 156. And the input image data, the input image data itself is output. On the other hand, if the determination result of the specific document determination unit 132 is a specific document, data “0” is set in the register 156 from the main CPU 91, and the logic of the output of the register 156 and the input image data in the AND circuit 157 is set. By taking the product, the output becomes data “0” regardless of the input image data.
[0054]
FIG. 6 shows a configuration example of a specific pattern addition circuit inside the first specific pattern addition unit 135 and the second specific pattern addition unit 140. This circuit includes a main scanning counter 161, a sub-scanning counter 162, a first lookup table (LUT1) 163, a second lookup table (LUT2) 164, an AND circuit (AND) 165, a selector unit 166, and an addition It is comprised by the device 167.
[0055]
The operation of the circuit of FIG. 6 will be described. The main scanning counter 161 counts the image clock, thereby counting 8 bits in the main scanning direction, and is reset by the line synchronization signal. The sub-scanning counter 162 counts the line synchronization signal, thereby counting 8 bits in the sub-scanning direction, and is reset by the page synchronization signal.
[0056]
The first look-up table 163 stores 1-bit data indicating whether or not to add a specific pattern to the output reproduced image (duplicated image). The upper 4 bits (D7) of the output of the main scanning counter 161 are stored. ˜D4) are addresses of the lower 4 bits (A3 to A0) of the first lookup table 163, and the upper 4 bits (D7 to D4) of the output of the sub-scanning counter 162 are the upper 4 bits of the first lookup table 163. Each is input to the address of bits (A7 to A4). Therefore, the first lookup table 163 outputs the contents of the lookup table shown in FIG. 7 every 16 clocks in the main scanning direction and every 16 lines in the sub scanning direction.
[0057]
The second look-up table 164 stores 2-bit data for determining the dot configuration of a specific pattern to be added to the output reproduced image (duplicated image). The lower 4 bits (D3) of the output of the main scanning counter 161 are stored in the second lookup table 164. ˜D0) are the addresses of the lower 4 bits (A3 to A0) of the second lookup table 164, and the lower 4 bits (D3 to D0) of the output of the sub-scanning counter 162 are the upper 4 bits of the second lookup table 164. Each is input to the address of bits (A7 to A4). Therefore, the second lookup table 164 outputs the contents of the lookup table shown in FIG. 7 every clock.
[0058]
The 1-bit output of the first lookup table 163 is expanded to 2 bits, the logical product with the 2-bit output of the second lookup table 164 is taken by the AND circuit 165, and the result is controlled by the selector unit 166. Input as a signal. In the selector unit 166, “0” is input when the input 2-bit control signal is “00”, “K1” is “01”, “K2” is “10”, and “11” is “11”. K3 ″ is selectively output as an 8-bit signal, and the adder 167 sums the output of the selector unit 166 and the input image data, whereby the contents of the look-up tables 163 and 164 are obtained for the image data. It is possible to add a specific pattern according to the above.
[0059]
Note that the specific pattern addition circuit included in the first specific pattern addition unit 135 and the second specific pattern addition unit 140 always operates regardless of whether the input image data is a specific document or not. A specific pattern capable of specifying the device is added to the image data.
[0060]
Further, the specific pattern added to the image data by the first specific pattern adding unit 135 and the specific pattern added to the image data by the second specific pattern adding unit 140 are not necessarily the same pattern. Is an apparatus-specific pattern that can identify the image forming apparatus.
[0061]
The specific document determination unit 132 determines whether there is a specific document based on the similarity by comparing the input RGB image data with the image data of the specific document stored in advance. The data is sent to the CPU 91 (or the scanner CPU 100 and the printer CPU 110), the filter processing unit 134, and the gradation processing unit 139.
[0062]
If the input image data is not a specific document as a result of the determination by the specific document determination unit 132, the filter processing unit 134 and the gradation processing unit 139 perform normal image processing, and the processing units subsequent to the respective processing units Image data is sent out.
[0063]
On the other hand, as a result of the determination by the specific document determination unit 132, if the input image data is a specific document, the filter processing unit 134 prohibits, for example, sending image data from the filter processing unit 134 to the subsequent processing unit. Ordinary image processing, such as prohibiting the reading of an original image by the color scanner unit 1 or replacing the input image data with image data that is completely different from the input image data and sending the image data to a subsequent processing unit Perform different image processing.
[0064]
When image data is not output to the outside via the image output interface 136, the gradation processing unit 139 performs processing corresponding to image processing different from normal image processing performed by the filter processing unit 134. Also good.
[0065]
FIG. 9 shows the configuration of the image processing apparatus 36 according to the second embodiment in detail. The second embodiment is different from the first embodiment in that the specific pattern adding unit is provided on each of the color scanner unit 1 side and the color printer unit 2 side in the first embodiment. In this embodiment, only one specific pattern adding unit is provided and shared by the color scanner unit 1 side and the color printer unit 2 side.
[0066]
That is, as shown in FIG. 9, a selector unit 141 and a specific pattern adding unit 142 are provided between the filter processing unit 134 and the gradation processing unit 139, and YMCK image data output from the filter processing unit 134 is output as an image. When outputting to an external device via the interface 136, the selector switch 141 on the input side of the selector unit 141a is set to the b side and the selector switch 141 on the output side of the selector switch group 141b is set to the a side. The yellow (Y) image data among the YMCK image data output from the filter processing unit 134 is sent to the specific pattern adding unit 142 via the b side of the changeover switch group 141a, and the specific pattern is added here. Is sent to the image output interface 136 via the a side of the switch group 141b. , Image data of MCK non Ierou (Y) is sent to the image output interface 136 via a side of the b-side and changeover switch group 141b of the changeover switch group 141a.
[0067]
On the other hand, when YMCK image data is input from an external device via the image input interface 137, the selector switch 141 on the input side of the selector switch group 141a is set to the a side, and the selector unit 141 on the output side of the selector switch 141 is set. By setting the group 141b to the b side, the yellow (Y) image data among the YMCK image data input from the image input interface 137 is sent to the specific pattern adding unit 142 via the a side of the changeover switch group 141a. After a specific pattern is added, the image data of MCK other than yellow (Y) is sent to the gradation processing unit 139 via the b side of the changeover switch group 141b. It is sent to the gradation processing unit 139 via the a side of 141a and the b side of the changeover switch group 141b.
[0068]
Even with the configuration described above, the image data is output to an external device via the image output interface 136 and the image is input via the image input interface 137 as in the first embodiment. In any case where data is input from an external device and when the image forming apparatus itself reproduces an image, a specific pattern can be added to the image data. Similar effects can be obtained.
[0069]
As described above, according to the above-described embodiment, the specific document determination unit 132 is provided before the image output interface 136 on the color scanner unit 1 side. Abuse can be prevented and forgery of a specific document can be prevented even when image data is output to an external device via the image output interface 136.
[0070]
In addition, by providing the first specific pattern adding unit 135 before the image output interface 136, a specific pattern can be added to the image data output to the external device, and the printer does not have the specific pattern adding function. Even in the case of outputting image data, etc., since a specific pattern has already been added to the image data itself, it is possible to prevent abuse of the output product (replicated image).
[0071]
Furthermore, by providing the second specific pattern adding unit 140 at a stage after the image input interface 137 on the color printer unit 2 side, a specific pattern is always added to the image data even when image data is input from an external device. It is possible to prevent abuse of the output product (duplicated image).
[0072]
【The invention's effect】
As described above in detail, according to the present invention, forgery of a specific document can be prevented even when image data read from a document is output to an external device, and an image for forming a duplicate image from another external device can be prevented. It is possible to provide an image forming apparatus that can prevent abuse of a duplicate image even when data is input.
[Brief description of the drawings]
FIG. 1 is a side view schematically showing an internal configuration of an image forming apparatus such as a digital color copying machine according to an embodiment of the present invention.
FIG. 2 is a block diagram schematically showing a signal flow for electrical connection and control of the image forming apparatus shown in FIG. 1;
FIG. 3 is a block diagram showing the configuration of the image processing apparatus according to the first embodiment.
FIG. 4 is a block diagram illustrating a first circuit configuration example that outputs an image processing result different from normal image processing.
FIG. 5 is a block diagram illustrating a second circuit configuration example that outputs an image processing result different from normal image processing.
FIG. 6 is a block diagram showing a configuration example of a specific pattern addition circuit inside the specific pattern addition unit.
FIG. 7 is a diagram showing an internal address configuration of a first lookup table in a specific pattern addition circuit.
FIG. 8 is a diagram showing an internal address configuration of a second lookup table in the specific pattern addition circuit.
FIG. 9 is a block diagram showing a configuration of an image processing apparatus according to a second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Color scanner part (image reading means), 2 ... Color printer part (image forming means), 30 ... Main control part, 36 ... Image processing apparatus, 91 ... Main CPU, 131 ... Input processing part, 132... Specific document determination unit (specific document determination unit) 133... Color conversion unit (color conversion unit) 134... Filter processing unit (first image processing unit) 135. Parts (first specific pattern adding means), 136 ... image output interface (image output interface means), 137 ... image input interface (image input interface means), 138 ... selector part (selection means) 139... Gradation processing section (second image processing means), 140... Second specific pattern addition section (second specific pattern addition means), 141... Selector section (selection means), 14 ...... specific pattern adding unit (specific pattern adding means).

Claims (3)

Image reading means for reading an image from a document and outputting image data separated into red, green and blue ; and
Input processing means for inputting image data separated into red, green and blue output from the image reading means;
Specific document determination means for determining whether the red, green, and blue image data output from the input processing means is a specific document set in advance;
Color conversion means for converting red, green, and blue image data output from the input processing means into cyan, magenta, yellow, and black image data;
First, image processing of cyan, magenta, yellow, and black image data output from the color conversion means is performed, and when the specific document determination means determines that the document is a specific document, first image processing for forgery prevention is performed. Image processing means,
First specific pattern adding means for adding a specific pattern to yellow image data output from the first image processing means;
The yellow image data added with the specific pattern output from the first specific pattern adding means and the cyan, magenta, yellow and black image data output from the first image processing means are output to the outside. Image output interface means for
Image input interface means for inputting cyan, magenta, yellow, and black image data from outside,
Select either cyan, magenta, yellow, or black image data input from the image input interface means , or cyan, magenta, yellow, or black image data output from the first image processing means. A selection means;
Second processing is performed to perform image processing for cyan, magenta, yellow, and black image data selected by the selecting means, and to perform image processing for preventing forgery when the specific original determining means determines that the original is a specific original. Image processing means;
Second specific pattern adding means for adding a specific specific pattern capable of specifying the image forming apparatus to yellow image data output from the second image processing means;
An image for forming an image on a recording medium based on the image data to which the specific pattern is added by the second specific pattern adding unit and the cyan, magenta, and black image data output from the second image processing unit. Forming means;
An image forming apparatus comprising: The specific document determination unit, red outputted from the image reading means, green, red specific original which is set in advance the image data of blue, green, against the blue image data, both red, green, and blue The image forming apparatus according to claim 1, wherein the image forming apparatus determines whether the red, green, and blue image data output from the image reading unit is a specific document based on the similarity of the image data. Image reading means for reading an image from a document and outputting image data separated into red, green and blue ; and
Input processing means for inputting image data separated into red, green and blue output from the image reading means;
Specific document determination means for determining whether the red, green, and blue image data output from the input processing means is a specific document set in advance;
Color conversion means for converting red, green, and blue image data output from the input processing means into cyan, magenta, yellow, and black image data;
First , image processing of cyan, magenta, yellow, and black image data output from the color conversion means is performed, and when the specific document determination means determines that the document is a specific document, first image processing for forgery prevention is performed . Image processing means,
Image input interface means for inputting cyan, magenta, yellow, and black image data from outside,
Cyan inputted from the image input interface unit, select magenta, Ierou, cyan outputted from the image data or the first image processing means, the black click, magenta, Ierou, one of the image data of black First selection means to
Specific pattern adding means for adding a specific specific pattern capable of specifying the image forming apparatus to the yellow image data selected by the first selection means ;
Whether yellow image data to which a specific pattern is added by the specific pattern adding means and cyan, magenta, and black image data selected by the first selecting means are output to the outside or an image is formed. A second selection means for selecting;
When the second selection means selects to output to the outside, yellow image data to which a specific pattern is added by the specific pattern addition means and cyan, magenta, selected by the first selection means, Image output interface means for outputting black image data to the outside;
The yellow image data to which the specific pattern is added by the specific pattern adding unit and the cyan, magenta, and black selected by the first selecting unit when the second selection unit selects to form an image. Second image processing means that performs image processing on the image data and performs image processing for preventing forgery when the specific original determination means determines that the original is a specific original ;
Image forming means for forming an image on a recording medium based on cyan, magenta, yellow, and black image data image-processed by the second image processing means ;
An image forming apparatus comprising:

Images