JP3320113B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a function of detecting a specific document.

[0002]

2. Description of the Related Art In recent years, with the increase in image quality and color of copiers, there has been a risk of forgery of specific documents such as banknotes and securities. In recognizing specific documents such as copiers,
Various schemes have been proposed. As an example, there is a method of forming an image by a frame sequential method. In order to form an image in a sequential manner, for example, an original is read for one side and color-separated, the cyan component is first copied one side, and then the same original is read again for one side and the magenta component is overlaid on the previous copy paper. Copy.
By repeating this operation for yellow and black, a full-color image is formed. For this reason, the detection of a specific document
If it is performed while reading the original for three pages, forgery can be prevented by printing a pattern or the like that appears to be counterfeit at first glance on the entire surface of the copy paper at the time of the final black color printing.

As another example, a four-color image is printed for each pixel to form a full-color image in pixel order.
There is a so-called dot-sequential type image forming apparatus. In this case, when a specific document is detected, one copy of the specific document has already been copied. Originally, the copied original document is overprinted or the like to prevent forgery.

[0004]

However, in the dot-sequential system, if an operation such as copy stop is performed before the specific document is completely detected, the copy output is performed. There is a risk of being done. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described drawbacks of the related art, and has as its object to provide an image forming apparatus capable of completely preventing counterfeiting even in an image forming apparatus using dot sequential printing. .

[0005]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the above object, an image forming apparatus according to the present invention is an image forming apparatus having an image forming unit that forms a visible image according to input image data, wherein the input unit inputs an instruction regarding image formation by the image forming unit. If, determination means for determining similarity between the input image data and the previously prepared specific image data, the determination result by the determining means out
Up to this point, there is provided control means for invalidating the instruction from the input means.

[0006]

According to this structure, the input means inputs an instruction relating to image formation by the image forming means, the determining means determines the similarity between the input image data and the specific image data prepared in advance, and the control means determines the similarity. Until the judgment result by means
Invalidates the instruction by the input means.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment according to the present invention will be described below in detail with reference to the accompanying drawings. In the following embodiments, a copying apparatus will be described as an embodiment of the present invention. However, the present invention is not limited to this and can be applied to other various apparatuses. Further, in each device applicable to the present invention, specific manuscripts such as bills, securities, confidential documents, etc. are targeted for counterfeit prevention.

<First Embodiment> FIG. 1 is an external perspective view showing a shape of a digital color copying machine according to a first embodiment of the present invention. The upper part of FIG. 1 is a color image scanner 1 for reading a document image and outputting digital color image data.
(Hereinafter, referred to as a “scanner unit”), and a controller unit 2 that is built in the scanner unit 1 and performs various image processing of digital color image data and has a processing function such as an interface with an external device. .

The lower part of FIG. 1 shows a printer unit 3 for recording a color digital image signal output from the controller unit 2 on recording paper. The two parts described above are separable and can be installed remotely by extending the connecting cable. FIG. 2 is a side sectional view showing the internal configuration of the digital color copying machine of FIG.

First, a platen glass 17 is exposed by an exposure lamp 14, a lens 15, and an image sensor 16 of a CCD capable of reading a line image in full color.
A document image placed on the top, a projected image by the projector, or a sheet document image by the output feed mechanism 12 is read.
Next, various kinds of image processing are performed by the scanner unit 1 and the controller unit 2, and the printer unit 3 records the image on a recording sheet.

In FIG. 2, the recording paper is composed of a paper feed cassette 20 for storing cut paper of a small fixed size (A4 to A3 size in this embodiment) and a large size (A2 to A1 size in this embodiment). Roll paper 2 for recording
9 is fed. In addition, paper can be fed from the outside of the apparatus (manual paper feeding) by feeding recording sheets one by one from the manual feed slot 22 in FIG. 1 along the paper feeding unit cover 21. The pick-up roller 24 is a roller for feeding cut sheets one by one from the sheet cassette 20. The fed cut sheet is conveyed to the first sheet feed roller 26 by the cut sheet feed roller 25. You. Roll paper 29
Is sent out by the roll feed roller 30 and the cutter 31
The sheet is cut into a standard length by the above, and is conveyed to the first sheet feeding roller 26. Similarly, the recording paper inserted from the manual feed port 22 is conveyed to the first paper feed roller 26 by the manual feed roller 32.

The pick-up roller 24, cut paper feed roller 25, roll paper feed roller 30, first paper feed roller 26, and manual feed roller 32 are driven by an attached paper feed motor (for example, a CD servo motor). On / off control can be performed at any time by an electromagnetic clutch attached to each roller. When the printing operation is started by an instruction from the controller unit 2, the recording paper selected and fed from any of the above-described paper feeding paths is fed to the first roller 26.
Transport to In order to remove the skew of the recording paper, a first paper feed roller 26 is turned on after a predetermined amount of paper loop is formed, and the recording paper is conveyed to a second paper feed roller 27.

First paper feed roller 26 and second paper feed roller 27
In order to perform an accurate paper feed operation between the paper feed roller 28 and the second paper feed roller 27, the recording paper is slacked by a predetermined amount to form a buffer. Buffer amount detection sensor 33
Is a sensor for detecting the buffer amount. By always making the buffer during paper transport, the load on the paper feed roller 28 and the paper feed second roller 27 can be reduced, especially when large format recording paper is transported, and accurate paper feed operation is possible. become.

When printing with the recording head 37,
A scanning carriage 34 on which a recording head 37 and the like are mounted performs reciprocating scanning on a carriage rail 36 by a scanning motor 35. In the forward scan, the paper feed roller 28 is used.
Is performed to feed the recording paper by a predetermined amount. At this time, the driving system is connected to the buffer amount detection sensor 3 by a paper feed motor.
The control is performed such that the buffer amount always becomes a predetermined value while detecting by (3).

The printed recording paper is stored in a discharge tray 23.
And the printing operation is completed. FIG. 3 is a diagram showing a configuration around the scanning carriage 34 according to the first embodiment. In FIG. 3, a paper feed motor 40 is a drive source for intermittently feeding recording paper, and drives the second paper feed roller 27 via a paper feed roller 28 and a second paper feed roller clutch 43. The scanning motor 35 is a drive source for causing the scanning carriage 34 to scan in the directions indicated by arrows A and B via the scanning belt 34. In this embodiment, a pulse motor is used for the paper feed motor 40 and the scanning motor 35 because accurate paper feed control is required. The recording paper is fed to the second roller 27
Is reached, the paper feed second roller clutch 43 and the paper feed motor 40 are turned on, and the recording paper is transported on the platen 39 to the paper feed roller 28.

The recording paper is detected by a paper detection sensor 44 provided on the platen 39, and the sensor information is used for position control and jam control. Recording paper is paper feed roller 2
When the number reaches 8, the second paper-feed roller clutch 43 and the paper feed motor 40 are turned off, and a suction operation is performed from inside the platen 39 by a suction motor (not shown) to bring the recording paper into close contact with the platen 39.

Prior to the image recording operation on the recording paper, the scanning carriage 34 is moved to the position of the home position sensor 41, and then the outward scanning is performed in the direction of arrow A, and cyan C and magenta are moved from the predetermined positions. M, yellow Y, and black K inks are ejected from the recording head 37 to record an image. When image recording for a predetermined length is completed, the scanning carriage 34 is stopped, and conversely, backward scanning is started in the direction of arrow B, and the scanning carriage 34 is returned to the position of the home position sensor 41. During the backward scanning, the paper is fed in the direction of arrow C by driving the paper feed paper feed roller 28 by the paper feed motor 40 by feeding the paper by the length recorded by the recording head 37.

In the present embodiment, the recording head 37 is an ink jet nozzle of the above-described type, and the recording head 37 is composed of 256 nozzles each having Y, M, C, and K assemblies.
I use this book. The scanning carriage 34 is a step / sensor 41
When the recording is stopped at the home position detected in step (3), the recovery operation of the recording head 37 is performed. This is a process for performing a stable printing operation. In order to prevent unevenness at the start of ejection due to a change in viscosity of ink remaining in the nozzles of the printing head 37, the feeding time, the internal temperature of the apparatus, etc. This is a process for performing a pressurizing operation to the recording head 37, an idle discharge operation of the ink, and the like according to pre-programmed conditions such as a discharge time.

The image recording is performed on the entire surface of the recording paper by repeating the operation described above. Next, the operation of the scanner unit 1 will be described. FIG. 4 is a diagram showing a mechanism inside the scanner section 1 according to the first embodiment. The CCD unit 18 is a CCD
A main scanning motor 50 and a pulley 5 fixed on a rail 54.
1. A main scanning direction drive system including a pulley 52 and a wire 53 moves on the rail 54 to read an image on the document glass 17 in the main scanning direction. The light shielding plate 55 and the home position sensor 56 are used for position control when the CD unit 18 is moved to the main scanning home position in the correction area 68 in the figure.

The rail 54 is mounted on rails 65 and 69, and has a sub-scanning motor 60, pulleys 67, 68, 71,
It is moved by a drive system in the sub-scanning direction consisting of a shaft 76, shafts 72 and 73, and wires 66 and 70. The light-shielding plate 57 and the home position sensors 58 and 59 are used for position control when the rail 54 is moved to the respective home positions for sub-scanning in the book mode for reading a document such as a book placed on the platen glass 17. Used for

The sheet feed motor 61, the sheet feed rollers 74 and 75, the pulleys 62 and 64, and the wire 63 are mechanisms for feeding a sheet document. This mechanism is a mechanism for feeding a sheet document placed on the document table glass 17 and placed downward by a predetermined amount by sheet feed rollers 74 and 75. FIG. 5 is a diagram for explaining a reading operation in the book mode and the sheet mode according to the first embodiment.

In the book mode, the CCD is placed in the illustrated book mode home position (indicated by the book mode HP in the drawing) in the correction area indicated by 68 in FIG.
The unit 18 is moved, and the reading operation of the entire surface of the original placed on the original platen glass 17 is started from here. Prior to the scanning of the document, parameters necessary for processes such as shading correction, black level correction, and color correction are set in the correction area 68. Thereafter, the main scanning motor 5 is moved in the direction of the illustrated arrow.
0 starts scanning in the main scanning direction. When the reading operation of the area indicated by is completed, the main scanning motor 50 is rotated in the reverse direction, and the sub-scanning motor 60 is driven to move the correction area 68 of the area in the sub-scanning direction. Subsequently, as in the main scanning of the area, processing such as shading correction, black level correction, and color correction is performed as necessary, and the area is read.

By repeating the above scanning, the reading operation of the entire area is performed. After the reading operation of the area is completed, the CCD unit 18 is returned to the book mode home position again. In the present embodiment, the original body glass 17 can read an original of maximum A2 size, so in practice, it is necessary to perform a large number of scans if it is held. However, in this explanation, the operation is simplified for easy understanding. I have.

In the sheet mode, the CCD unit 1
8 is moved to the illustrated sheet mode home position (sheet mode HP), and the area of the sheet document is repeatedly read while the sheet feed motor 61 is intermittently operated to read the entire area of the sheet document. Prior to the scanning of the document, processing such as shading correction, black level correction, and color correction is performed in the correction area 68, and then scanning in the main scanning direction is started by the main scanning motor 50 in the direction of the arrow shown in the figure. When the reading operation of the forward path in the area is completed, the main scanning motor 50 is rotated in the reverse direction, and the sheet feed motor 61 is driven during the backward scanning to move the sheet document by a predetermined amount in the sub-scanning direction. Then repeat the same operation,
Scans the entire sheet document.

Assuming that the above-described reading operation is an equal-magnification reading operation, the area that can be read by the CCD unit 18 is actually a large area as shown in FIG. This is because the digital color copying machine of the present embodiment has a built-in magnification / reduction zooming function. That is,
As described above, the area that can be recorded by the recording head 37 is fixed at 256 bits at a time.
In the case of performing the% reduction operation, image information of at least twice the area of 512 bits is required. Therefore, the scanner unit 1 has a function of reading and outputting image information of an arbitrary image area by one main scanning reading.

FIG. 6 is a block diagram showing the configuration of the digital color copying machine according to the first embodiment. In the figure, control units 102, 111, and 121 respectively include a scanner unit 1,
It is a control circuit for controlling the controller unit 2 and the printer unit 3, and includes a micro computer, a program ROM,
It is composed of a data memory, a communication circuit and the like. Control unit 1
The communication lines 02 to 111 and the control units 111 to 121 are connected by a communication line, and a so-called master / slave control mode in which the control units 102 and 121 operate according to an instruction from the control unit 111 is adopted.

When operating as a color copying machine, the control unit 111 operates according to input instructions from the control unit 10 and the digitizer 114. As shown in FIG. 6, the scanning unit 10 includes, for example, a liquid crystal (LCD display unit 84) as a display unit.
And use a touch and transparent electrode on the surface.
By providing the panel 85, it is possible to perform selection instructions such as designation of a color and designation of an editing operation. In addition, keys for operations, such as a start key 87 for instructing a start of a copying operation, a stop key 88 for instructing a stop of a copying operation, a reset key 89 for returning an operation mode to a standard state, and a projector (not shown) are selected. Projector Key 8
Frequently used keys such as 6 are provided independently.

The digitizer 114 is for inputting position information indicating a processing area such as trimming, masking processing, color conversion, etc., and is connected as an option when complicated editing processing is required. Further, the control unit 111 includes, for example, a control circuit of a general-purpose parallel interface such as IEEE-488, a so-called GP-IB interface = I /
The control of the F control unit 112 is also performed, so that input / output of image data between external devices and remote control by the external devices can be performed through this interface.

Further, the control unit 111 includes a multi-value synthesizing unit 106 for performing various processes relating to the image, an image processing unit 107,
It also controls the value processing unit 108, the binary synthesis unit 109, and the buffer memory 110. The control unit 102 controls the mechanism driving unit 105 which controls the mechanism of the scanner unit 1 described above, the exposure control unit 103 which controls the exposure of the lamp for reading the reflection original, and the halogen control when the projector is used.
The exposure controller 104 controls the exposure of the lamp 90. Further, the control unit 102 includes an analog signal processing unit 100 that performs various types of processing related to an image, an input image processing unit 10
Control 1 is also performed.

The control unit 121 is the printer unit 3 described above.
Mechanism driving unit 105 for controlling the driving of the mechanism, absorption of the time variation of the mechanical operation of the printer unit 3 and the recording head 11
It controls the synchronous delay memory 115 which performs delay correction based on the arrangement of 7 to 120. Next, the image processing block of FIG. 6 will be described along the flow of images.

The image formed on the CCD 16 is a CCD
The input signal is converted into an analog electric signal by 16. The converted image information is serially processed in the order of red → green → blue and input to the analog signal processing unit 100. The analog signal processing unit 100 performs sample-and-hold, dark level correction, dynamic range control, etc. for each color of red, green, and blue, and then performs analog-to-digital conversion (A / D conversion), and performs serial multi-value conversion. (In this embodiment, each image is converted into a digital image signal of 8 bits in length.)
Output to 1.

The input image processing unit 101 similarly performs correction processing necessary for a reading system such as shading correction, color correction, and γ correction on a digital image signal of a serial touch. The multi-level synthesizing unit 106 of the controller unit 2 selects the serial multi-level digital image signal sent from the scanner unit 1 and the serial multi-level digital image signal sent via the parallel I / F, and This is a circuit block for performing the combining process. The selected image data is sent to the image processing unit 107 as a serial multi-valued digital image signal.

The image processing unit 107 performs a smoothing process,
This circuit performs edge enhancement, black extraction, masking processing for color correction of recording ink used in the recording heads 117 to 120, and the like. The serial multi-valued digital image signal output is input to a binarization processing unit 108 and a buffer memory 110, respectively. The binarization processing unit 108 is a circuit for binarizing a serial multilevel digital image signal.
Simple binary processing using a fixed slice level, pseudo halftone processing using a dither method, and the like can be selected. Here, the serial multi-valued digital image signal is converted into a binary parallel image signal of four colors. Image data of four colors is sent to the binary synthesizing unit 109, and image data of three colors is sent to the buffer memory 110. 2
The value synthesizing unit 109 includes a three-color binary parallel image signal sent from the buffer memory 110 and the binary processing unit 10.
This is a circuit for selecting and combining the four-color binary parallel image signals sent from 8 and converting them into four-color binary parallel image signals. The buffer memory 110 has a parallel I / O
It is a buffer memory for inputting and outputting a multi-valued image and a binary image via F, and has memories for three colors.

The synchronous delay memory 115 of the printer unit 3
This is a circuit for canceling the time variation of the mechanical operation of the printer unit 3 and correcting the delay due to the mechanical arrangement of the recording heads 117 to 120. The recording heads 117 to 12 are internally provided.
The timing necessary for driving 0 is also generated. The head driver 116 is an analog drive circuit for driving the recording heads 117 to 120, and
20 is generated internally. The recording heads 117 to 120 respectively discharge cyan, magenta, yellow, and black inks to record an image on recording paper.

FIG. 7 is a timing chart of an image between the circuit blocks described in FIG. The signal BVE is a signal indicating an image effective section for each scan in the main scanning reading operation described with reference to FIG. By outputting the signal BVE a plurality of times, image output of the entire screen is performed. The signal VE is C
It is a signal indicating an effective section of an image for each line read by the CD16. Only the signal VE when the signal BVE is valid is valid.

The signal VCK is a clock signal for sending out the image data VD. The signals BVE and VE also change in synchronization with the signal VCK. The signal HS is a signal used when the signal VE is output one line, and is valid when the valid and invalid sections are discontinuously repeated. When the signal VE is valid continuously while the one line is output, the signal HS is an unnecessary signal. is there. This signal indicates the start of image output of one line.

Reference numeral 123 denotes a determination unit, and the binary synthesis unit 109
The binary image data of each color of C, M, Y, and Bk sent through the synchronous delay memory 115 is used to correct the head-to-head delay, and then printed and recorded by the recording heads 117 to 120 at the same time. It is also supplied to the image determination unit 123.
The image determination unit 123 compares the supplied binary image data with the pre-registered specific image data in real time, and when the similarity with the image data corresponding to the specific document is high as described later. Includes a control unit 121
And a print operation is interrupted. At this time, it goes without saying that the control unit 121 also notifies the control units 102 and 111 of the fact.

In the case of a digital full-color copying machine as shown in this embodiment, an I / F is connected via a host computer or the like.
Since the binary image data can be directly printed via the control unit 112 and the buffer memory 110, in order to prevent the printing of the specific image data by this route, the image determination unit 123 needs The determination must be made from the binary image data.

FIG. 8 shows the image determining unit 12 according to the first embodiment.
3 is a block diagram showing the configuration of FIG. In FIG.
Reference numeral 1 denotes a shift register for converting the serially transmitted C, M, Y, and Bk pixel signals into parallel signals.
A timing control unit (not shown) converts C, M, Y, and Bk serial binary image data into parallel signals. 80
Reference numeral 2 denotes a binary / multi-valued conversion circuit which converts binary image data converted in parallel by the shift register 801 into multi-valued image data of 5 bits per color. Here, the bit width is 4
The bits are set on condition that the processing load on the circuits after this stage is reduced and that the specific original can be detected with sufficient accuracy. Further, the image data subjected to the binary / multi-value conversion is thinned out and subjected to the multi-value conversion so that one pixel is multi-value converted every four pixels. This is also for the same reason as described above.

Reference numeral 803 denotes a color matching lookup table (hereinafter, referred to as “color matching LUT”).
This is a ROM that performs matching of colors, which are image characteristics of a plurality of types of specific originals. 804-1, 804-2, ..., 8
A color judgment circuit 04-8 is composed of integrators 805 and 807 indicated by 805 and a comparator indicated by 806, and a specific original exists in the image data. Is determined. Reference numeral 808 denotes an OR circuit.
When it is determined that one or more of the outputs 1 to 804-8 include the specific document to be processed, the output “1” is output as the determination signal H.

Next, the binary / multi-value conversion section 802 will be described in detail. 9 to 11 are diagrams for explaining a processing method of the binary / multi-value conversion unit 802 according to the first embodiment. As shown in FIG. 9, this is performed by performing area processing on the input binary image data. In the present embodiment, as shown in FIG.
The density level of the pixel of interest denoted by reference numeral 901 is obtained by calculating the sum of each cell in which the image data exists using a × 5 matrix. At this time, a weighting factor is set for each cell, and the value resulting from this weighting factor is the data of each cell.

As shown in FIG. 10, when the weighting factors of the matrix are x _i and y _j , the density level e of the pixel of interest is given by the following equation (1).

[0043]

(Equation 1)

Is obtained by Here, a is image data and is 1 or 0 because it is a binary image. FIG. 11 shows the weighting coefficients in this embodiment. In this case, when the density is the highest, the density level is (61) decimal, so that 2
In hexadecimal, all the densities can be expressed with a data width of 5 bits.

FIG. 12 is a diagram for explaining a method of thinning out image data and performing multi-value conversion in the first embodiment. FIG.
After the target pixel 1201 is multi-valued in 2, the image data to be multi-valued next is multi-valued using the image data obtained by skipping four pixels as the target pixel. The above processing of the binary / multi-value conversion unit 802 has an independent circuit for each of C, M, Y, and Bk colors. As described above, the image data of each color of C, M, Y, and Bk subjected to the binary / multi-value conversion is represented by the color matching LUT 803 in FIG.
Is input to

The color matching LUT 803 examines the color distribution of eight specific documents in advance, and retains the result of determining whether the color of the pixel matches the color of the specific documents. . That is, the color matching LUT
803 has 20-bit address lines, each having 5 bits.
The C, M, Y, and Bk color pixel data multi-value converted by the binary multi-value conversion unit 802 is input for each bit.
The data output line of the color matching LUT 803 has 8 bits, and one bit corresponds to one type of specific original.
A determination is made on a total of eight types of specific originals.

FIG. 13 shows an integrator 805 according to the first embodiment.
It is a block diagram which shows a structure of. In FIG.
1 and 1305 are flip-flops for holding data at the rising timing of the CLK signal. 130
Reference numeral 2 denotes a multiplier which receives an 8-bit 2-input signal (A, B) and outputs an 8-bit signal (A × B / 25) as a multiplication result.
5) is output. A multiplier 1303 also receives a 1-bit input signal (A) and an 8-bit input signal (B), and outputs an 8-bit output signal (A × B) as a multiplication result. An adder 1304 receives an 8-bit 2-input signal (A, B) and outputs an 8-bit signal (A + B) as an addition result.

As a result, in the integrator 805,
For a binary input signal x _i , an 8-bit output signal y _i is
It is expressed by the following equation (2). That is, y _i = (α / 255) y _i-1 + β. x _{i -1} (2) where α and β are preset constants, and various characteristics of the integrator 805 are determined by the magnitudes of these values.

Thus, as an example, a case where α = 247 and β = 8 will be described. FIGS. 14 and 15 are diagrams showing an example of input and output of the integrator 805 according to the first embodiment.
For an input xi _-1 as shown in FIG. 14, an output _yi as shown in FIG. 15 is output. Where 1401,
An input that is almost “0” as in the point 1402 but is almost “1”, or an input that is almost “1” as in the point 1403, It is considered to be noise. This was treated by the integrator 805, and excisional the appropriate threshold, such as the level shown in 1404 in the register 807 in FIG. 8, the output y _i of this by the integrator 2
By converting to a value, noise (noise) can be removed.

In the binarization result obtained in this way, the data which becomes 1 is counted by a counter (not shown). When the total number obtained by the counting exceeds a certain threshold value, it is finally determined that the document is a specific document (hereinafter, the coefficient value of the binarized data is simply abbreviated as a counting value. Continue to accumulate for three scans,
When a specific document does not exist, the document is cleared every three scans, and erroneous detection is prevented when image data of a color close to the specific document is dispersed on a wide document surface. In the case of this embodiment, even if the short side of a specific document such as a bill is scanned in one scan, three scans can sufficiently detect the specific document. Is cleared.

A specific judgment sequence according to the present embodiment will be described with reference to FIGS. FIG.
In FIG. 18, the vertical axis represents the sum of coefficient counts, and the horizontal axis represents one-time scanning. FIG. 16 shows an example of a case where a specific original is present on the original and detected.

In FIG. 16, reference numeral 1501 denotes an original;
Specific document 1 to be determined by this device in part of the image
503 are present. The output result when this is copied in this apparatus is 1502. In the portion corresponding to the specific document 1503, a case where the document is a specific document is detected at the point 1504 in the third scan.
The amount of the image to be copied until it is determined that the document is a specific document varies depending on the type of the document, the manner of placing the document on the platen, and the like. However, in the description of this embodiment, it is assumed that the image is detected at the third scan. In this way, if a specific document is printed even after a few scans before it is finally detected, if the key to stop copying or the reset key is operated after the specific document has been recorded to some extent, the specific document will be printed. It is partly copied. For this reason, a complete copy can be obtained by copying several times as described above while shifting the specific original placed on the scanner little by little and pasting the copy output of each part.

In the present embodiment, a first threshold value TH0 and a second threshold value TH1 are provided for the binarized result coefficient to prevent such inconvenience. FIGS. 17 and 18 are diagrams showing the transition of the count value as a result of the binarization. As described above, FIGS. 17 and 18 show two threshold values TH0 and TH1 for determining a specific document. TH1 is a threshold value for judging that a specific original is included in the original. When TH1 is exceeded, the copying operation is immediately interrupted, and the printout that has already been output is invalidated as described later. Perform the conversion process. On the other hand, TH0 is set as a threshold value indicating that the document is likely to be a specific document, although it is not yet determined whether the document is a specific document.

In this embodiment, TH0 is set during scanning of the original.
Is exceeded, the copying operation is not interrupted at that point.
The key input by the stop key or the like of the operation unit 10 is invalidated, and the original is forcibly scanned until it can be completely determined that the original is a specific original. This process is continued while scanning the document as far as it can be completely determined that the document is a specific document.

In the case of the present embodiment, even if the short side of a bill is three scans, the judgment can be made completely. Therefore, when the sum of the coefficients exceeds the threshold value TH0, a margin is taken. The key input is invalidated for the scan and the document is forcibly scanned. Naturally, this scan is no different from a normal copying operation unless a key operation is intentionally performed. As a result, when the specific document is about to be copied, it exceeds TH1, and it can be completely detected that the document is the specific document, and the copy image is invalidated. Conversely, if the original does not have a specific color but contains similar colors, it does not exceed TH1 during the three scans, so the key input hold is released and normal copying is continued. This means that the copying sequence has been completed normally.

FIG. 17 is a diagram showing a change in the count value for each scan when a specific document is placed on the document table as shown in FIG. In FIG. 17, the value exceeds TH0 at the first scan of 1701, and at this point, the key operation from the operation unit is invalidated, and the next three scans are forcibly scanned. In this example, since the third scan exceeds TH1, no subsequent scan is performed.

FIG. 18 is a diagram showing the transition of the count value similarly to FIG. 17, but shows a case where there is no specific original. The three scans at 1801 in FIG. 18 are when there is a slight color image close to the specific document, and when three scans do not exceed TH0. In this case, the count value is cleared when three scans have been completed. Reference numeral 1802 in the drawing denotes a case where the specific document does not exist, but a lot of image data of a color close to the specific document exists. In this case, the count value is TH at the second scan.
At this point, the key input is invalidated, and the subsequent three scans are forcibly continued. During this time, the count value is accumulated without being cleared. In this case as well, there is no specific document, which means that TH1 has not been exceeded. Thereafter, the count value is cleared, and at the same time, the invalidation of the key input is released, and the coefficient for every three scans is restarted. The above operation is performed until one image is copied, and the similarity of the entire original to the specific original is checked.

Next, a process of invalidating a copied image after it is determined that the document is a specific document will be described. If it is detected that the document is a specific document, the key input is kept invalid. The scanning of the original by the scanner unit 1 is immediately interrupted. In contrast, the CPU of the control unit 121 of the printer unit 3 shown in FIG. 6 writes a pattern for invalidating the already copied specific document into the synchronization delay memory 115. In this embodiment, it is a 4 mm square grid pattern of BK color. Thereafter, the printer section overlaps and prints the grid pattern on the recording paper on which the grid pattern has already been copied, and invalidates the copied image. This processing will be described with reference to FIG. The carriage 34 mounted with the recording head 37 returns to the home position 44 without feeding the recording paper 38 in the sub-scanning direction. Then, in order to record the lattice pattern from above the already recorded image, scanning is performed in the direction A. When the scanning is completed, the carriage 34 is returned in the direction B, and at the same time, the recording paper 38 is fed in the direction opposite to the normal recording, so that the sub-scanning motor 40 is reversed. Thereby, the recording paper 38 is fed in the direction opposite to the direction C. Then, the lattice pattern is recorded again on the copy image so as to overlap. The above operation is repeated for three scans, and a grid pattern is recorded so as to overlap the entire copy image including the specific document. When this processing is completed, the apparatus enters an irrecoverable error state and an equalized state, and cannot operate unless special processing is performed by a service person.

The same processing is performed not only when copying an original, but also when printing an image obtained from a host computer device such as a computer, so that a specific image is not normally printed. . In this case, the processing for the command transmitted through the interface such as the GP-IB (general purpuse interface bus) described above is invalidated. As a result, the same effect as that for the original image can be obtained for the computer image.

As described above, according to the first embodiment, when it is not possible to completely detect a specific original and there is a possibility that the specific original is present, the operator, the host computer, etc. Even if a copy stop instruction is issued, the copy stop instruction is not accepted immediately, and the copy stop instruction is suspended until it can be completely determined whether the document is a specific document. Printing is not performed, and printing of a specific image can be prevented beforehand.

Further, the matrix size and the weighting factor of the binary / multi-value conversion unit 802 shown in the first embodiment are not limited to these, but may vary depending on the type of a specific document, the characteristics of the binary printer, and the like. Can be installed arbitrarily. Also, it goes without saying that the bit width of the data of the image to be multi-valued converted is not limited to 5 bits in this embodiment. Further, if the configuration is such that only multi-valued image data is processed with a device such as a host computer, the multi-valued image conversion unit 802 is not required, and the multi-valued image can be directly determined. Absent.

<Second Embodiment> In the second embodiment, a third threshold is newly added in addition to the first and second thresholds described in the first embodiment. To set. In the second embodiment as well, the first and second threshold values perform the same processing as in the first embodiment for the operation unit.
The third threshold value TH2 is equal to T3 as shown by 1901 in FIG.
It is set to a level lower than H0.

Therefore, as described in the first embodiment, 3
The processing in the case where the binarization results are integrated during scanning and the situation exceeds TH2 but does not exceed TH0 will be described.
In such a case, the key input is not invalidated, but if the copy stop key or the reset key is pressed in this state,
The control unit 111 in FIG. 6 changes the processing for these key inputs so as to store this in a non-volatile memory (not shown). Thereafter, during the three scans, the coefficient becomes TH2 again.
Is exceeded, and when the stop or reset key is pressed again, the content of the memory is incremented. Conversely, if such a situation does not occur, the contents of the memory are cleared. This process is repeated, and when the count value of the memory exceeds a certain value, it is determined that the specific document is being copied one copy at a time, and as in the first embodiment, an unrecoverable error is detected. State, and the copying is disabled. As described above, by increasing the threshold value, it is possible to more completely prevent copying of a specific document.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. In each of the above-described embodiments, a so-called bubble jet printer using a head of a type that discharges droplets using film boiling due to thermal energy has been described as an example, but the present invention is not limited to this. Instead, the present invention can be applied to a piezo-type ink jet printer and a thermal transfer printer. In each of the above-described embodiments, the original image is input by the image scanner. However, the present invention is not limited to this.
A still video camera, a video camera input, and a video created by computer graphics may be used.

[0065]

As described above, according to the present invention, when it is not possible to completely detect a specific original and there is a possibility that the specific original is present, an operator, a host computer, etc. Even if a copy stop instruction is issued, it is not immediately accepted, but the copy stop instruction is suspended until it is completely determined that the document is a specific document, so that even a part of the specific document can be printed. The printing of the specific image can be prevented beforehand.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing the shape of a digital color copying machine according to a first embodiment of the present invention.

FIG. 2 is a side sectional view showing an internal configuration of the digital color copying machine of FIG.

FIG. 3 is a diagram showing a configuration around a scanning carriage according to the first embodiment.

FIG. 4 is a diagram showing a mechanism inside the scanner section 1 according to the first embodiment.

FIG. 5 shows a book mode and a sheet mode according to the first embodiment.
FIG. 9 is a diagram illustrating a reading operation in a mode.

FIG. 6 is a block diagram showing the configuration of the digital color copying machine according to the first embodiment.

FIG. 7 is a timing chart of an image between circuit blocks described in FIG. 6;

FIG. 8 is a block diagram illustrating a configuration of an image determining unit 123 according to the first embodiment.

FIG. 9 is a diagram illustrating a processing method of a binary / multi-value conversion unit 802 according to the first embodiment.

FIG. 10 is a diagram for explaining a processing method of the binary / multi-value conversion unit 802 according to the first embodiment.

FIG. 11 is a diagram illustrating a processing method of a binary / multi-value conversion unit 802 according to the first embodiment.

FIG. 12 is a diagram illustrating a method of performing multi-value conversion by thinning out image data in the first embodiment.

FIG. 13 is a block diagram showing a configuration of an integrator 805 according to the first embodiment.

FIG. 14 is a diagram illustrating an example of input and output of the integrator 805 according to the first embodiment.

FIG. 15 is a diagram illustrating an example of input and output of the integrator 805 according to the first embodiment.

FIG. 16 is a diagram illustrating an example of a processing result according to the first embodiment.

FIG. 17 is a diagram illustrating an example of a count value according to the first embodiment.

FIG. 18 is a diagram illustrating an example of a count value according to the first embodiment.

FIG. 19 is a diagram illustrating a relationship between scanning and a threshold according to the second embodiment.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 image scanner unit 2 controller unit 3 printer unit 12 sheet feed mechanism 15 lens 16 CCD 17 platen glass 18 CCD unit 20 paper feed cassette 22 manual feed port 23 paper discharge tray 24 pick-up roller 25 cut paper feed roller 26 feed Paper first roller 27 Paper feed second roller 28 Paper feed roller 29 Roll paper 30 Roll paper feed roller 31 Cutter 33 Buffer amount detection sensor 34 Scanning carriage 35 Scanning roller 36 Carriage rail 37 Recording head 39 Platen 40 Paper feed motor 41 , 56 Home position sensor 43 Paper feed second roller clutch 50 Main scanning motor 51, 52, 62, 64, 67, 68, 71, 76 Pulley 53, 66, 70 Wire 54, 65, 66 Rail 55 Light shielding plate 60 sub-scan Motor 61 Sheet feed motor 68 Correction area 72, 73 axis 74, 75 Sheet feed roller 85 Touch panel 86 Projector key 87 Start key 88 Stop key 89 Reset key 90 Halogen lamp 100 Analog signal processing unit 101 Input image processing Units 102, 111, 121 Control unit 105 Mechanical drive unit 106 Multi-level synthesizing unit 107 Image processing unit 108 Binarization processing unit 109 Binary synthesizing unit 110 Buffer memory 112 I / F control unit 114 Digitizer 115 Synchronous delay memory 117 to Reference Signs List 120 recording head 123 image determination unit 801 shift register 802 binary / multi-value conversion unit 803 color matching LUT 804-1 to 804-8 color determination circuit 805 integrator 806 comparator 807 register 808 OR circuit

Claims (3)

(57) [Claims] 1. An image forming apparatus having image forming means for forming a visible image in accordance with input image data, comprising: input means for inputting an instruction relating to image formation by said image forming means; and said input image data being prepared in advance. An image forming apparatus comprising: a determination unit configured to determine a degree of similarity with the specified image data; and a control unit configured to invalidate an instruction from the input unit until a determination result is obtained by the determination unit. Wherein said determination means image forming apparatus according to claim 1, characterized in that to determine the degree of similarity according to the distribution of color of the input image data. Wherein said image forming means to the input image data
The image forming apparatus according to claim 1 , wherein a visible image is formed according to binary data obtained by binarization by pseudo halftone processing .