JP2007078981A - Image forming apparatus, printing instruction device, and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To impart security even when invisible toner for imparting the security is deficient or can not be used. <P>SOLUTION: A document image and a code image are taken out (S301), and it is discriminated whether a supply means of the invisible toner is mounted or not (S302), and a toner residual amount in the supply means is discriminated (S303). When the toner residual amount in the supply means is sufficient as a result, the document image and the code image are combined as they area (S308). When the supply means is mounted but the toner residual amount is deficient, selection of an output condition is prompted (S304), and the code image is reduced in accordance with a selected output condition (S305), and then selection of an output condition is prompted (S305) when the supply means is not mounted or the toner amount is zero, and processing according with a selected output condition is performed (S307), and then the document image and the code image are combined (S308). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printer or a copying machine, and more particularly to an image forming apparatus that enables full color image formation.

  In recent years, the need for security for paper documents has been rapidly increasing. In order to provide such security, information for preventing or inhibiting forgery of a paper document or guaranteeing its originality is widely embedded in a paper document. In addition, today, as the entire society is sensitive to handling personal information, such as the enforcement of the Personal Information Protection Law, it is important to provide such security in order to prevent information leakage due to copying of paper documents. Has been. In particular, since information leakage is often caused by actions in the organization, it is necessary for the user to perform security assignment on all paper documents, not on the paper documents individually. For these reasons, it has been proposed to provide security as invisible information that is difficult to see using special toners, not as visible information that is visible (see, for example, Patent Document 1).

  However, when security is provided using special toner in this way, if the special toner is insufficient, security cannot be provided to the paper document. Here, for a general shortage of toner, a method for warning the user of the shortage of the remaining amount and reducing the recording density to prevent sudden printing (see, for example, Patent Document 2), A method of performing pseudo black printing using color toner in response to a shortage of black toner remaining (for example, see Patent Document 3) is known.

JP 2004-12880 (page 6-8, Fig. 1-3) JP-A-10-207319 (pages 4, 5 and 1) Japanese Unexamined Patent Publication No. 2004-237657 (page 6, FIG. 7)

As described above, in an image forming apparatus capable of providing security using a special toner as in Patent Document 1, if the security-providing toner runs short, security may be added to a paper document. There was a problem that it was impossible.
For such problems, the techniques of Patent Documents 2 and 3 do not provide any effective solution. That is, only a general method for dealing with toner shortage is disclosed, and no effective method for dealing with invisible toner for providing security is disclosed.

The present invention has been made to solve the technical problems as described above, and an object of the present invention is to provide security even when the invisible toner for providing security is insufficient. There is.
Another object of the present invention is to provide security even in a situation where invisible toner for providing security cannot be used.

  For this purpose, in the present invention, when the invisible toner supply means is not attached or the amount of toner in the supply means is insufficient, an alternative image is supplied when there is a problem in the supply of invisible toner. Security was given to the medium by the forming method. That is, the image forming apparatus according to the present invention is capable of forming a document image with visible toner and forming a machine-readable code image with invisible toner, and detection for detecting a defect in the supply of invisible toner. And the image forming means changes the forming method while maintaining the machine-readable state of the code image in accordance with the supply failure of the invisible toner detected by the detecting means.

  Here, when the amount of toner in the invisible toner supply means is smaller than a predetermined amount but is a printable amount, the code image forming method is a method that reduces the amount of invisible toner used. It is preferable to change to. When the invisible toner supply unit is not attached or the amount of toner in the supply unit is smaller than the printable amount, the code image forming method is changed to a method that does not use invisible toner. It is preferable.

  The present invention can also be understood as a print instruction apparatus that issues a print instruction to the image forming apparatus. In this case, the printing instruction apparatus according to the present invention stores information on whether or not the invisible toner can be used for a plurality of image forming apparatuses including at least one image forming apparatus capable of printing a code image with the invisible toner. And receiving means for receiving a print instruction for a specific image forming apparatus among the plurality of image forming apparatuses, and information indicating that the invisible toner cannot be used for the specific image forming apparatus. A transmission unit configured to transmit a print instruction to another image forming apparatus in which information indicating that the toner can be used is stored;

  On the other hand, the present invention can also be regarded as a method for providing security to a medium by an alternative means when there is a problem in the supply of invisible toner. In that case, the image forming method of the present invention is an image forming method in an image forming apparatus capable of forming a document image with visible toner and forming a machine-readable code image with invisible toner. And detecting a supply failure and forming a code image while maintaining its machine-readable state in a manner corresponding to the detected invisible toner supply failure.

  According to the present invention, it is possible to provide security even when the invisible toner for providing security is insufficient.

The best mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be described below in detail with reference to the accompanying drawings.
FIG. 1 shows an example of the configuration of a system to which the present embodiment is applied. In this system, at least a terminal device 100 that instructs to print an electronic document, a document repository 200 that stores the electronic document, and an image forming apparatus 300 that superimposes the code image on the image of the electronic document and prints the network 900. It is configured by being connected. The system also includes a printed material 500 output from the image forming apparatus 300 and a pen device 600 that records characters or graphics on the printed material 500 and reads the trajectory of the characters or graphics. Further, a terminal device 700 that displays the locus received from the pen device 600 and the electronic document acquired from the document repository 200 in an overlapping manner is also connected to the network 900.

The outline of the operation of this system will be described below.
First, the terminal device 100 acquires an electronic document to be printed from the document repository 200 (A). Then, it instructs the image forming apparatus 300 to print the electronic document (B). At this time, the terminal device 100 designates a printing attribute that is a parameter related to printing. As in normal printing, the print attributes include paper size, orientation, reduction / enlargement, double-sided printing, N-up (printing in which N pages of an electronic document are allocated within one page of paper), and the like. In addition, regarding the code image, designation of an area in which the code image is to be printed may be included.
Upon receiving this electronic document print instruction, the image forming apparatus 300 prints an image in which the code image is superimposed on the image of the electronic document on a medium such as paper, and outputs a printed matter 500. In this case, the code image is an image of the identification code corresponding to the identification information and the position code corresponding to the position information. Alternatively, it may be an image including additional information which is other information.

Here, as the identification information, information for uniquely identifying each medium can be adopted. For example, it may be information obtained by combining the identification number of the image forming apparatus 300 and the serial number of printing of the medium in the image forming apparatus 300 or the date and time of printing. It may be managed information. Alternatively, information that uniquely identifies an electronic document printed on a medium may be adopted as identification information instead of information that uniquely identifies each medium.
The position information is information for specifying the coordinate position (X coordinate, Y coordinate) on each medium. For example, it is conceivable to express coordinates in a coordinate system set by taking the upper left point of the medium as the origin, taking the X axis in the right direction of the medium and the Y axis in the lower direction. Alternatively, a plurality of coordinate systems may be set on one medium, such as providing a coordinate system for each region instead of one coordinate system.
Further, the additional information includes the identification information of the user who issued the print instruction, information about whether copying is prohibited, or the like.

  Further, the image forming apparatus 300 forms the code image as an invisible image using an invisible toner whose infrared light absorption rate is equal to or higher than a certain reference. On the other hand, it is preferable that the document image of the electronic document is formed as a visible image using a visible toner having an infrared light absorption rate which is equal to or lower than a certain reference. The difference in the absorption rate of infrared light between the toner used for forming the code image and the toner used for forming the document image is that the reading accuracy when reading the code image by irradiating the infrared light is increased. This is to ensure. In this specification, the description is based on the premise that the code image is read by infrared light irradiation, but the code image may be read by ultraviolet light.

Thereafter, it is assumed that the user has written characters or figures on the printed material 500 using the pen device 600 (D). Thereby, the pen device 600 inputs a code image by irradiating the printed matter 500 with infrared light and detecting the reflected light. Then, information is acquired or generated from the code image, and the information is transmitted to the terminal device 700 via wired communication or wireless communication (E). The information transmitted here includes, for example, identification information of the printed matter 500 and position information of characters or figures written on the printed matter 500. Alternatively, the position information may be transmitted as trajectory information obtained by connecting the position information of characters or figures at a certain time.
Thereafter, based on the identification information received from the pen device 600, the terminal device 700 acquires an electronic document that is a source of the document image printed on the printed material 500 from the document repository 200 (F). Then, the electronic document acquired from the document repository 200 and the information acquired from the pen device 600 are superimposed and displayed.

By the way, when the identification information received from the pen device 600 is information that uniquely identifies each medium, in order to be able to acquire an electronic document based on this identification information, the identification information and the electronic document It is necessary to manage the correspondence. In FIG. 1, it is not clearly shown where to manage this correspondence, but it may be managed where it can be accessed from the terminal device 700. For example, the document repository 200 or the image forming apparatus 300 may be used. When the identification information received from the pen device 600 is information that uniquely identifies the electronic document printed on the medium, the electronic document can be acquired without referring to such correspondence.
Further, when the trajectory information is received from the pen device 600, the trajectory information is displayed superimposed on the position on the electronic document corresponding to the writing position on the printed matter 500. This is because the code image read by the pen device 600 includes writing position information, and the corresponding position in the display image of the electronic document can be specified from the information.

Although the system to which the present embodiment is applied has been described above, such a configuration is merely an example. For example, the function of an image processing unit (described later) for superimposing a document image and a code image in the image forming apparatus 300 may be realized by the terminal device 100, the document repository 200, or other devices. Further, the document repository 200 may be in the terminal device 100. Furthermore, the terminal device 100 and the terminal device 700 may be the same terminal device.
In this specification, the term “electronic document” is used, but this does not mean only data obtained by digitizing a “document” including text. For example, “electronic document” includes image data such as pictures, photographs, figures, etc. (regardless of raster data or vector data) and other printable electronic data.

FIG. 2 is a diagram illustrating a functional configuration of the image forming apparatus 300. Here, it is assumed that the code image is an image of the identification code and the position code.
The image forming apparatus 300 includes an instruction input unit 31, a document image generation unit 33, a document image buffer 34, an information acquisition unit 35, a code image generation unit 36, a code image buffer 37, an image composition unit 38, An image forming unit 400 and a detection unit 45 are provided.
The code image generation unit 36 includes a position information encoding unit 36a, a position code generation unit 36b, an identification information encoding unit 36c, an identification code generation unit 36d, a code arrangement unit 36g, and a pattern storage unit 36h. And a code imaging unit 36i.

The instruction input unit 31 inputs a print instruction including an electronic document to be printed and a print attribute from the terminal device 100. Here, the print instruction is input as PDL (Page Description Language) represented by PostScript or the like.
The document image generation unit 33 extracts information necessary for image formation of the electronic document from the print instruction, converts the electronic document into an image, and stores the image in the document image buffer 34.
The information acquisition unit 35 acquires identification information and position information. Here, the identification information can be acquired by combining the identification number of the image forming apparatus 300 and the serial number of printing of the medium in the image forming apparatus 300 or the printing date and time. Alternatively, it may be obtained by requesting the server that manages the identification information to issue identification information for the number of copies. Or if the identification information of an electronic document is employ | adopted, identification information should just be extracted from the attribute information sent with an electronic document. On the other hand, the position information can be appropriately acquired according to the paper size and orientation included in the print attribute.

The code image generation unit 36 generates a code image based on the information acquired by the information acquisition unit 35 and stores it in the code image buffer 37.
The image composition unit 38 composes the document image stored in the document image buffer 34 and the code image stored in the code image buffer 37, and transmits the composite image to the image forming unit 400.
The image forming unit 400 prints out the received composite image. Note that the image forming unit 400 forms the code image using a color material that cannot be easily identified by the human eye (invisible), and forms the document image by the human eye (visible) color material that can be identified by the human eye. Form using. The invisible color material has a characteristic of absorbing a large amount of a specific wavelength in the infrared region, and the visible color material has a characteristic of not absorbing the specific wavelength so much.
The detection unit 45 detects the toner supply status of the image forming unit 400 and notifies the image composition unit 38 of the supply status.

When the position information is input, the position information encoding unit 36a encodes the position information by a predetermined encoding method. For this encoding, for example, an RS (Reed Solomon) code or a BCH code which is a known error correction code can be used. Also, CRC (Cyclic Redundancy Check) or checksum value of position information can be calculated as an error detection code and added to the position information as redundant bits. Also, an M-sequence code that is a kind of pseudo-noise sequence can be used as position information. That is, in the case of a P-order M sequence (sequence length 2 ^P-1 ), when a partial sequence of length P is extracted from the M sequence, the bit pattern that appears in the partial sequence appears only once in the M sequence. Can be used for position encoding.
The position code generation unit 36b converts the encoded position information into a format embedded as code information, and generates a position code. For example, the arrangement of each bit in the encoded position information can be replaced or encrypted with a pseudo-random number or the like so that it is difficult for a third party to decipher. When the position code is two-dimensionally arranged, the bit value is two-dimensionally arranged in the same manner as the code arrangement.

When the identification information is input, the identification information encoding unit 36c encodes the identification information by a predetermined encoding method. For this encoding, a method similar to that used for encoding the position information can be used.
The identification code generation unit 36d converts the encoded identification information into a format embedded as code information, and generates an identification code. For example, the arrangement of each bit in the encoded identification information can be replaced or encrypted with a pseudo-random number so that it is difficult for a third party to decipher. When the identification code is two-dimensionally arranged, the bit value is two-dimensionally arranged in the same manner as the code arrangement.

The code arrangement unit 36g generates a two-dimensional code by synthesizing the two-dimensionally arranged position code and the identification code, and generates a two-dimensional code array by arranging the two-dimensional codes in a number corresponding to the output image size. To do. At this time, as the position code, a code obtained by encoding position information different depending on the arrangement position is used, and as the identification code, a code obtained by encoding the same identification information regardless of the arrangement position is used.
The code imaging unit 36i confirms the bit values of the array elements in the two-dimensional code array, acquires a pattern image corresponding to each bit value from the pattern storage unit 36h, and obtains a code image obtained by imaging the two-dimensional code array Is output.

  These functional parts are realized by cooperation between software and hardware resources. Specifically, a CPU (not shown) of the image forming apparatus 300 externally transmits a program that realizes the functions of the instruction input unit 31, the document image generation unit 33, the information acquisition unit 35, the code image generation unit 36, and the image composition unit 38. Processing is performed by reading from the storage device to the main storage device.

  FIGS. 3A to 3C are diagrams for explaining a code image generated by the code image generation unit 36 described above. FIG. 3A schematically shows a two-dimensional code array formed as an invisible image. FIG. 3B is an enlarged view of the two-dimensional code that is one unit of the two-dimensional code array in FIG. Further, FIG. 3C is a diagram for explaining a pattern image of backslash “\” and slash “/”.

  In the present embodiment, the code images shown in FIGS. 3A to 3C have a maximum absorption rate of, for example, 7% or less in the visible light region (400 nm to 700 nm), and the near infrared region (800 nm to 1000 nm). For example, an invisible toner having an absorption rate of 30% or more. The invisible toner has an average dispersion diameter in the range of 100 nm to 600 nm in order to enhance the near infrared light absorption capability necessary for machine reading of an image. Here, “visible” and “invisible” are not related to whether they can be recognized visually. “Visible” and “invisible” are distinguished depending on whether or not an image formed on a printed medium can be recognized by the presence or absence of color development due to absorption of a specific wavelength in the visible light region.

  In addition, the code image is formed as an invisible image that can be machine-readed and decoded by infrared light irradiation stably over a long period of time and can record information at a high density. Furthermore, it is preferable that the image is an invisible image that can be provided in an arbitrary area regardless of the area where the visible image on the medium surface that outputs the image is provided. Furthermore, for example, an invisible image that can be recognized by a difference in gloss when visually observed is more preferable. For example, an invisible image is formed on the entire surface of the medium (paper surface) in accordance with the size of the medium to be printed. However, “entire surface” does not mean to include all four corners of the sheet. In an apparatus such as an electrophotographic system, the area around the paper surface is usually a non-printable range, and therefore it is not necessary to print an invisible image in such a range.

  The two-dimensional code shown in FIG. 3B includes an area in which a position code indicating a coordinate position on the medium is stored, and an area in which an identification code for uniquely specifying the medium or the like is stored. It also includes an area for storing the synchronization code. As shown in FIG. 3A, a plurality of the two-dimensional codes are arranged on the medium surface in a lattice pattern. That is, a plurality of two-dimensional codes as shown in FIG. 3B are arranged on the medium surface, each of which includes a position code, an identification code, and a synchronization code. In the plurality of position code areas, different position information is stored depending on the place where each area is arranged. On the other hand, the same identification information is stored in the areas of the plurality of identification codes regardless of the place where they are arranged.

  In FIG. 3B, the position code is arranged in a 6 bit × 6 bit rectangular area. Each bit value is formed by a plurality of minute line bit maps having different rotation angles, and the bit value 0 and the bit value 1 are expressed by the pattern image (pattern 0 and pattern 1) shown in FIG. . More specifically, bit 0 and bit 1 are expressed using backslash “\” and slash “/” having different inclinations. The pattern image is composed of 600 dpi and a size of 8 × 8 pixels. A diagonally upward pattern image (pattern 0) has a bit value 0, and a diagonally upward pattern image (pattern 1) has a bit value 1. Express. Therefore, 1-bit information (0 or 1) can be expressed by one pattern image. Providing a two-dimensional code that can embed a large amount of information with high density by minimizing noise given to a visible image by using such a minute line bitmap having two kinds of inclinations. Is possible.

That is, a total of 36-bit position information is stored in the position code area shown in FIG. Of these 36 bits, 18 bits can be used for encoding the X coordinate, and 18 bits can be used for encoding the Y coordinate. When used in the encoding of all positions of each 18 bit, are two ¹⁸ position (about 260,000) can be encoded. If each pattern image is composed of 8 pixels × 8 pixels (600 dpi) as shown in FIG. 3C, one dot of 600 dpi is 0.0423 mm, so that FIG. The size of the two-dimensional code (including the synchronization code) is about 3 mm (8 pixels × 9 bits × 0.0423 mm) both vertically and horizontally. When 260,000 positions are encoded at intervals of 3 mm, a length of about 786 m can be encoded. In this way, all 18 bits may be used for position coding, or when a pattern image detection error occurs, redundant bits for error detection and error correction may be included. .
The identification code is arranged in a rectangular area of 2 bits × 8 bits and 6 bits × 2 bits, and can store a total of 28 bits of identification information. When using the 28-bit as the identification information can be represented the identity of two ways ²⁸ (about 270 million). Similarly to the position code, the identification code can include redundant bits for error detection and error correction in 28 bits.

In the example shown in FIG. 3C, the two pattern images are 90 degrees apart from each other, but if the angle difference is 45 degrees, four types of pattern images can be configured. When configured in this way, 2-bit information (0 to 3) can be expressed by one pattern image. That is, the number of bits that can be expressed can be increased by increasing the angle types of the pattern image.
In the example shown in FIG. 3C, the coding of the bit value is described using the pattern image, but other than the pattern image may be adopted. For example, it is possible to perform encoding according to the ON / OFF state of the dot or the direction in which the dot position is shifted from the reference position.

  FIG. 4 is a diagram illustrating the configuration of the image forming unit 400 in FIG. 2 and illustrates a so-called tandem mechanism. The image forming unit 400 includes an image process system 410 that forms an image corresponding to gradation data of each color, a sheet transport system 430 that transports recording paper (sheets and media), and a control unit that controls the entire image forming unit 400. 440, for example, an IPS (Image Processing System) 450 that is connected to a personal computer (hereinafter referred to as “PC”), a scanner unit 445, and the like and performs predetermined image processing on received image data. ing. FIG. 4 is a view of the image forming unit 400 as viewed from the side where the user operates (front side).

  The image processing system 410 includes five images of yellow (Y), magenta (M), cyan (C), invisible (I), and black (K), which are arranged in parallel in the horizontal direction at regular intervals. Transfer units 411Y, 411M, 411C, 411I, and 411K, and transfer units that multiplex-transfer toner images of the respective colors formed on the photosensitive drums 412 of the image forming units 411Y, 411M, 411C, 411I, and 411K onto the intermediate transfer belt 421. 420 is provided. Further, a fixing device 429 is provided for fixing the image on the recording paper secondarily transferred by the transfer unit 420 to the recording paper using heat and pressure. Further, toner cartridges 419Y, 419M, 419C, 419I, and 419K are provided for supplying toner of each color to the image forming units 411Y, 411M, 411C, 411I, and 411K.

  In the present embodiment, each image forming unit 411 (411Y, 411M, 411C, 411I, 411K) has a charger 413 for charging the photosensitive drum 412 around the photosensitive drum 412 rotating in the direction of arrow A. A laser exposure unit 414 for writing an electrostatic latent image on the photosensitive drum 412; a developing unit 415 for storing each color component toner and developing the electrostatic latent image on the photosensitive drum 412 with toner; Electrophotographic devices such as a primary transfer roll 416 that transfers the formed color component toner images to the intermediate transfer belt 421 and a drum cleaner 417 that removes residual toner on the photosensitive drum 412 are sequentially disposed. These image forming units 411 are arranged in the order of yellow (Y), magenta (M), cyan (C), invisible (I), and black (K) from the upstream side of the intermediate transfer belt 421.

  The transfer unit 420 includes a drive roll 422 that drives the intermediate transfer belt 421, a tension roll 423 that applies a constant tension to the intermediate transfer belt 421, and a backup roll that performs secondary transfer of the superimposed toner images of each color onto a recording sheet. 424, and a belt cleaner 425 for removing residual toner and the like existing on the intermediate transfer belt 421. The intermediate transfer belt 421 is wound around the drive roll 422, the tension roll 423, and the backup roll 424 with a constant tension, and is rotated by a dedicated drive motor (not shown) having excellent constant speed. The drive roll 422 is circulated at a predetermined speed in the direction of arrow B. As the intermediate transfer belt 421, for example, a belt whose resistance is adjusted with a belt material (rubber or resin) that does not cause charge-up is used.

  The sheet conveyance system 430 includes a paper feed tray 431 that stacks and supplies recording paper (sheets and media) on which images are recorded, a nudger roll 432 that picks up and supplies recording paper from the paper feed tray 431, and a nudger roll 432. A feed roll 433 that separates and feeds the recording paper supplied from the paper one by one, and a transport path 434 that transports the recording paper separated by the feed roll 433 toward the image transfer unit. In addition, a registration roll 435 that conveys the recording sheet conveyed through the conveyance path 434 at a timing toward the secondary transfer position, and a backup roll 424 that is provided at the secondary transfer position and is in pressure contact with the recording sheet A secondary transfer roll 436 for secondary transfer of the image to the paper, a discharge roll 437 for discharging the recording paper on which the toner image is fixed by the fixing device 429, and a discharge tray 438 for stacking the recording paper discharged by the discharge roll 437. It has.

  The scanner unit 445 reads an image of a document placed on the platen glass or an image of the document conveyed on the platen glass by a CCD image sensor or the like (not shown). Here, in the image forming unit 400 according to the present embodiment, the scanner unit 445 is disposed on the upper side to save space. A predetermined gap is formed between the discharge tray 438 and the scanner unit 445 so that the recording paper after image formation discharged to the discharge tray 438 can be easily taken out.

Next, an image forming process of the image forming unit 400 will be described.
First, the image data generated by the image composition unit 38 in FIG. 2 is input to the IPS 450. The IPS 450 performs predetermined image processing on the input image data. The image data subjected to the image processing is converted into color material gradation data of five colors of yellow (Y), magenta (M), cyan (C), invisible (I), and black (K), and each image formation It is output to the laser exposure unit 414 of the units 411Y, 411M, 411C, 411I, 411K.

  In each of the image forming units 411Y, 411M, 411C, 411I, and 411K, the photosensitive drum 412 is charged to a predetermined potential by the charger 413. Further, in the laser exposure unit 414 of each of the image forming units 411Y, 411M, 411C, 411I, and 411K, the image forming units 411Y, 411M, 411C, 411I, and 411K are exposed in accordance with the color material gradation data input from the IPS 450. The body drum 412 is irradiated with laser light. On the photosensitive drum 412 of the image forming units 411Y, 411M, 411C, 411I, and 411K, the charged surface is exposed to form an electrostatic latent image. The formed electrostatic latent images are developed by the developing units 415 of the respective image forming units 411Y, 411M, 411C, 411I, and 411K, yellow (Y), magenta (M), cyan (C), invisible (I), It is developed as a toner image of each color of black (K).

  The toner images formed on the respective photosensitive drums 412 of the image forming units 411Y, 411M, 411C, 411I, and 411K are multiple transferred onto the intermediate transfer belt 421. At this time, since the image forming units 411Y, 411M, and 411C for forming yellow, magenta, and cyan toner images are provided on the most upstream side in the moving direction of the intermediate transfer belt 421, the yellow, magenta, and cyan toner images are provided. Are first primarily transferred to the intermediate transfer belt 421. Further, since the image forming unit 411I that forms an invisible toner image is provided second downstream in the moving direction of the intermediate transfer belt 421, the invisible toner image is the second to the intermediate transfer belt 421 from the last. Primary transfer. Further, since the image forming unit 411K that forms a black toner image is provided on the most downstream side in the moving direction of the intermediate transfer belt 421, the black toner image is finally primarily transferred to the intermediate transfer belt 421. . Then, the photosensitive drum 412 of the image forming units 411Y, 411M, 411C, 411I, and 411K after the transfer is cleaned by the drum cleaner 417.

  On the other hand, in the sheet conveyance system 430, the nudger roll 432 rotates in accordance with the image formation timing, and a recording paper of a predetermined size is supplied from the paper feed tray 431. The recording sheets separated one by one by the feed roll 433 are conveyed to the registration roll 435 through the conveyance path 434 and temporarily stopped. Thereafter, the registration roll 435 rotates in accordance with the movement timing of the intermediate transfer belt 421 on which the toner image is formed, and the recording paper is conveyed to the secondary transfer position formed by the backup roll 424 and the secondary transfer roll 436. . On the recording sheet conveyed from the lower side to the upper side at the secondary transfer position, the toner images in which the five colors are multiplexed are sequentially transferred in the sub-scanning direction using a pressing force and a predetermined electric field. The recording paper on which the toner images of the respective colors are transferred is subjected to a fixing process with heat and pressure by the fixing device 429 and then discharged to a discharge tray 438 provided at the upper portion by a discharge roll 437. On the other hand, the intermediate transfer belt 421 after the secondary transfer is cleaned by a belt cleaner 425 to prepare for the next process.

Next, image formation according to the supply state of invisible toner in the present embodiment will be described.
As shown in FIG. 2, in the present embodiment, a detection unit 45 that monitors the supply status of toner in the image forming unit 400 and detects a supply failure is provided. The detection unit 45 detects, for example, the mounting state of the toner supply unit and the toner remaining amount in the supply unit.
By the way, the detection unit 45 can detect the mounting state of each color toner supply unit and the remaining amount of toner in each supply unit. Description will be made by paying attention to detection of the remaining amount of toner in the supply means. Various toner supply means such as a toner cartridge and a developing device are conceivable. Here, a toner cartridge is exemplified.

For example, consider the case where the mounting positions of the toner cartridges for each color are determined as in the image forming unit 400 shown in FIG. In this case, it is possible to detect the mounting of the invisible toner cartridge by detecting that the toner cartridge is mounted at the mounting position of the invisible toner cartridge. On the other hand, for example, 4 toner cartridges are arbitrarily selected from five toner cartridges of yellow (Y), magenta (M), cyan (C), invisible (I), and black (K) with respect to the mounting positions of four toner cartridges. In the case of an image forming apparatus in which up to one toner cartridge is mounted, the uneven pattern of the lock mechanism that locks the toner cartridge is made different for each color, and the invisible toner cartridge is recognized by recognizing the uneven pattern. It is possible to detect whether it is attached.
In addition, the detection of the remaining amount of toner in the toner cartridge may be performed, for example, by providing an optical sensor near the toner cartridge, or may be performed by monitoring a change in toner density in response to a toner supply instruction.
Then, the detection unit 45 transmits the detection result signal to the image composition unit 38.
Thereby, the image composition unit 38 performs the following operation.

FIG. 5 is a flowchart showing the main operation of the image composition unit 38.
First, the image composition unit 38 takes out the document image stored in the document image buffer 34 by the document image generation unit 33 and the code image stored in the code image buffer 37 by the code image generation unit 36 (step 301). It should be noted that the document image and the code image taken out here are synchronized so that the document image and the code image to be printed on the same medium are taken out.
Here, the image composition unit 38 determines whether or not the invisible toner supply unit is attached based on the detection signal sent from the detection unit 45 (step 302).

As a result, if it is determined that the invisible toner is attached, the remaining amount of toner in the invisible toner supply unit is similarly examined based on the detection signal from the detection unit 45 (step 303).
Here, if it is determined that the toner remaining amount is sufficient, the code image can be superimposed and printed on the entire surface of the medium, so the image composition unit 38 composes the document image and the code image (step 308). .
If it is determined in step 303 that the remaining amount of toner is less than the predetermined amount but still remains to be printed, the image composition unit 38 informs the user and selects the output condition. A prompting display is performed (step 304). This display may be performed on the UI screen of the image forming apparatus 300 or may be performed on the screen of the user's PC via the printer driver.

The following are examples of output condition options.
(1-a) By reducing the pitch of the code image and printing, the consumption of invisible toner is reduced. For example, the pitch between adjacent minimum unit codes is expanded without changing the minimum decodable unit included in the code image.
(1-A) The consumption of invisible toner is reduced by reducing the information to be encoded. For example, the position information is not coded, but only the identification information is coded. In this case as well, the pitch between chords is widened as a result.
(1-c) The code information is printed not on the entire surface of the medium, but only on a specific location, thereby reducing the consumption of invisible toner. For example, code information is printed only on the upper left of the medium.

Alternatively, any of these options may be set in advance without performing the process of step 304.
When the output condition is determined, the image composition unit 38 performs code image reduction processing according to the output condition (step 305). The code image reduction process will be described in detail later.

  On the other hand, if it is determined in step 302 that the invisible toner supply unit is not attached, or it is determined that the remaining amount of toner in the invisible toner supply unit is less than the printable amount (almost zero). In such a case, image formation using invisible toner can no longer be performed. Accordingly, the image composition unit 38 notifies the user to that effect and displays a message prompting the user to select an output condition (step 306). This display may be performed on the UI screen of the image forming apparatus 300 or may be performed on the screen of the user's PC via the printer driver.

The following are examples of output condition options.
(2-a) A code image to be printed with invisible toner is printed with visible toner. In this case, the image is deteriorated, but the same code information as when printing with invisible toner can be maintained.
(2-i) Print the code image with a coarse pitch with visible toner. As a result, it is possible to reduce image degradation while ensuring security.
(2-c) The code information is printed with visible toner only on a specific portion, not on the entire surface of the medium. For example, code information is printed only on the upper left of the medium. As a result, it is possible to reduce image degradation while ensuring minimum security.
(2-d) Even when the print instruction is in the color mode, the document image is printed with black toner, and the code image is printed with color toner.
(2-E) Even if the print instruction is in the color mode, the document image is printed with a specific color visible toner, and the code image is printed with black toner. If the black toner has infrared absorption characteristics, it can be decoded in the same manner as when printing with invisible toner.
(2-F) Do not print the code image.
(2-ki) Similarly, a code image is not printed, except that it is no longer necessary to provide security to the document image. For example, a confidential information area is set in advance for a document image. The confidential information area is, for example, an area in which a name is described in the case of a document image related to personal information including a name and an attribute. Under such a setting, the code image is not printed on condition that the information in the confidential information area is not printed or is painted so that it cannot be read.

Alternatively, any of these options may be set in advance without performing the process of step 306.
When the output condition is determined, the image composition unit 38 performs processing corresponding to the output condition, that is, processing for changing the color attributes of the code image and the document image (step 307). For example, if (2-A) to (2-O), the color attribute of the code image is changed to be visible. In particular, it is changed to color in (2-D) and black in (2-O). In (2-d), the color attribute of the document image is changed to black, and in (2-e), the color attribute of the document image is changed to a specific color. Here, in (2-d) and (2-e), the color is specified and described, but any color may be used as long as the color of the code image and the color of the document image can be identified.

Next, the code image reduction process in step 305 in FIG. 5 will be described.
FIG. 6 shows an image of code image reduction processing.
Among these, FIG. 6A shows a state in which the code image is normally printed on the printed material 500. That is, a certain margin area is provided in the peripheral portion of the printed material 500, and the code image is printed in the inner area. In the figure, the code image is shown by shading. Here, each cell (minimum rectangle) constituting the area where the code image is printed indicates a unit of the code image corresponding to the two-dimensional code shown in FIG.
In this embodiment, such code images are reduced by converting them into those shown in FIGS. 6B to 6D.

First, FIG. 6B is an example of the conversion according to (1-a) described above. Here, as a simple method for coarsening the pitch of the code image, the odd-numbered and odd-numbered cells and the even-numbered and even-numbered cells print the code image, The code image is not printed in the cells in the even columns and the cells in the even rows and the odd columns.
FIG. 6C shows an example of conversion according to the above (1-i). Here, among the synchronization code, identification code, and position code arranged as shown in FIG. 3B, the position code is not printed as a code image. As a method of reducing the information to be encoded, not only the identification information and the position information are separated as described above, but also, for example, the type of information to be printed in the same identification information can be determined. Conceivable. For example, when the identification information includes a printer ID and an output date / time, the printer ID is printed, but the output date / time is not printed.
Further, FIG. 6D is an example of the conversion according to the above (1-c). Here, the code image is printed only in the upper right part. In the case of a medium for digitizing handwriting at an arbitrary position, the position code needs to be printed on the entire surface, so that the identification code is rather suitable for localization of such a code image.

Next, an example of an algorithm for performing the conversion of FIGS. 6B and 6C in the code image reduction processing shown in FIG. 6 will be described.
Here, the variable for counting the order (number of lines) in the vertical direction (Y direction) of the pattern image of FIG. 3C on the code image printed on the printed material 500 is “i”. A variable for counting the order (number of columns) in the horizontal direction (X direction) is “j”. Further, it is assumed that the number of pattern images included in the two-dimensional code corresponding to one cell is “k” in both the vertical direction and the horizontal direction (k = 9 in FIG. 3). Furthermore, the total number in the vertical direction of the pattern image printed on the printed material 500 is “n”, and the total number in the horizontal direction is “m”. Furthermore, the pattern image at the position of the i-th row and the j-th column is denoted as P (i, j).

FIG. 7 is a flowchart showing the operation of the reduction process of FIG. The image composition unit 38 performs this process on the code image extracted in step 301 of FIG.
First, the image composition unit 38 sets the initial value of i to 1 (step 311), and performs the processing of steps 312 to 328 until i becomes 1 while increasing i by 1.
That is, first, it is determined whether int ((i-1) / k), which is a quotient obtained by dividing (i-1) by k, is an even number (step 312). That is, it is determined whether or not the two-dimensional code including the line of interest is the even-numbered line as the number of lines of the two-dimensional code (the first line is the 0th line).

As a result, if it is an even-numbered row, the initial value of j is set to 1 (step 313), and steps 314 to 316 are performed until j is increased while j is incremented by 1.
That is, first, it is determined whether int ((j−1) / k), which is a quotient obtained by dividing (j−1) by k, is an even number (step 314). That is, it is determined whether or not the two-dimensional code including the column of interest is the even-numbered column as the number of columns of the two-dimensional code (the first column is the 0th column). Here, the image composition unit 38 leaves P (i, j) if the result is the even-numbered column (step 315), and deletes P (i, j) if the result is the odd-numbered column (step 316). . That is, among the code images developed in the memory, the image corresponding to the two-dimensional code of the even-numbered row and the even-numbered column is left as it is, and the image corresponding to the two-dimensional code of the even-numbered row and the odd-numbered column is deleted. To do.
Then, 1 is added to j (step 317), and it is determined whether j exceeds m (step 318). If it is determined that j does not exceed m, the process returns to step 314. If it is determined that j exceeds m, the process proceeds to step 329.

On the other hand, if the determination result in step 312 is an odd-numbered row, the initial value of j is set to 1 (step 323), and steps 324 to 326 are performed until j is increased while j is incremented by 1.
That is, first, it is determined whether int ((j-1) / k), which is a quotient obtained by dividing (j-1) by k, is an even number (step 324). That is, it is determined whether or not the two-dimensional code including the column of interest is the even-numbered column as the number of columns of the two-dimensional code (the first column is the 0th column). Here, the image composition unit 38 deletes P (i, j) if the result is an even-numbered column (step 325), and leaves P (i, j) if the result is an odd-numbered column. That is, of the code images developed in the memory, the image corresponding to the two-dimensional code of the odd-numbered row and the even-numbered column is deleted, and the image corresponding to the two-dimensional code of the odd-numbered row and the odd-numbered column is left as it is. deep.
Then, 1 is added to j (step 327), and it is determined whether j exceeds m (step 328). If it is determined that j does not exceed m, the process returns to step 324. If it is determined that j exceeds m, the process proceeds to step 329.

Thereafter, the image composition unit 38 adds 1 to i (step 329), and determines whether i exceeds n (step 330). If it is determined that i does not exceed n, the process returns to step 312, and if it is determined that i exceeds n, the process is terminated.
As described above, when both the number of rows and the number of columns of the cell are even numbers and when both are odd numbers, the code image is left, and either the number of rows or the number of columns of the cells is even or any of them is odd. In this case, the code image reduction as shown in FIG. 6B is realized by performing image processing that erases the code image.

FIG. 8 is a flowchart showing the operation of the reduction process of FIG. The image composition unit 38 performs this process on the code image extracted in step 301 of FIG.
First, the image composition unit 38 sets the initial value of i to 1 (step 331), and repeats the processing of steps 332 to 340 until i becomes 1 while increasing i by 1.
That is, first, it is determined whether mod (i / k), which is a remainder obtained by dividing i by k, is 1 (step 332). That is, it is determined whether the line of interest is the first line in the two-dimensional code.

As a result, if it is not 1, the row may include a code image corresponding to an identification code and a position code other than the synchronization code. Therefore, the initial value of j is set to 1 (step 333), and steps 334 to 338 are performed until j is increased while j is increased by 1.
That is, first, it is determined whether mod (j / k), which is a remainder obtained by dividing j by k, is 1 (step 334). That is, it is determined whether the column of interest is the first column in the two-dimensional code.
If the result is not 1, P (i, j) is either a code image corresponding to the identification code or a code image corresponding to the position code. Therefore, the image composition unit 38 determines whether or not the identification code is used (step 335). It is assumed that how the identification code and the position code are arranged is stored in the memory. If it is not an identification code, it is a position code, so P (i, j) is deleted (step 336).

  If the determination result in step 332 is 1, all code images in the row represent synchronous codes, so j = 1, 2,..., M (step 337), and all these j , P (i, j) is left (step 338). Further, P (i, j) is also left when it is determined at step 334 that it is 1 or when it is determined at step 335 that it is an identification code (step 338).

Thereafter, the image composition unit 38 adds 1 to i (step 340), and determines whether i exceeds n (step 341). If it is determined that i does not exceed n, the process returns to step 332, and if it is determined that i exceeds n, the process is terminated.
In this way, by performing image processing that leaves the code image corresponding to the synchronization code and the identification code and erases the position code, the reduction of the code image as shown in FIG. 6C is realized.

In the present embodiment, at the timing when the image composition unit 38 superimposes the document image and the code image, image processing for providing security without using invisible toner or with a small amount of invisible toner is performed. did. However, such image processing may be performed at any timing. For example, the instruction input unit 31 receives a print instruction and instructs the code image generation unit 36 and the document image generation unit 33 to generate a document image and a code image, respectively, and instruct a process for obtaining a similar result. It may be.
In this embodiment, the processing for providing security without using invisible toner or with a small amount of invisible toner is performed as image processing. However, the same processing is performed by the printing mechanism of the image forming apparatus 300. You may do it.

  Further, in the present embodiment, the image forming apparatus 300 performs processing for providing security without using invisible toner or with a small amount of invisible toner. Such a process may be performed by a device that relays. In that case, another option that can use invisible toner is available as an option when the invisible toner supply unit is not attached in step 302 in FIG. 5 or when the remaining amount of toner in the supply unit is close to zero in step 303. It is also possible to give a print instruction to the image forming apparatus.

  Specifically, in a print instruction apparatus that performs such a print instruction, first, a storage unit such as a memory receives invisible toner from a plurality of image forming apparatuses including at least one image forming apparatus capable of printing with invisible toner. Information on availability is acquired and stored. When the accepting unit accepts a print instruction for a certain image forming apparatus, the determining unit refers to the availability information in the memory and determines whether or not invisible toner can be used in the image forming apparatus. To do. As a result, if the invisible toner can be used, the transmission unit sends a print instruction to the image forming apparatus as it is. If the invisible toner cannot be used, the transmission unit transmits another invisible toner. A print instruction is sent to the image forming apparatus.

  As described above, in the present embodiment, when the invisible toner supply unit is not attached or the amount of toner in the supply unit is insufficient, the invisible toner supply is defective. The security was given to the medium by the image forming method. This makes it possible to provide security even when invisible toner for providing security is insufficient or even when invisible toner cannot be used.

1 is a diagram showing an overall configuration of a system to which an embodiment of the present invention is applied. 1 is a diagram illustrating an example of a functional configuration of an image forming apparatus according to an embodiment of the present invention. It is a figure for demonstrating the code image printed on a medium in embodiment of this invention. FIG. 3 is a diagram illustrating a configuration example of a printing mechanism of the image forming apparatus according to the embodiment of the present invention. It is the flowchart which showed the operation example of the image composition part in embodiment of this invention. It is a figure for demonstrating the outline | summary of the reduction process of the code image in embodiment of this invention. It is a flowchart for demonstrating the operation | movement along the specific example of the reduction process of the code image in embodiment of this invention. It is a flowchart for demonstrating the operation | movement along the specific example of the reduction process of the code image in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,700 ... Terminal device, 200 ... Document repository, 300 ... Image forming apparatus, 400 ... Image forming part, 500 ... Printed matter, 600 ... Pen device

Claims (11)

Image forming means capable of forming a document image with visible toner and forming a machine-readable code image with invisible toner;
Detecting means for detecting a defect in the supply of the invisible toner,
The image forming means changes the forming method while maintaining the machine-readable state of the code image in accordance with the supply failure of the invisible toner detected by the detecting means. apparatus.   The image forming unit may select a code image forming method selected from a plurality of methods presented according to the invisible toner supply failure, or according to the invisible toner supply failure. The image forming apparatus according to claim 1, wherein the image forming apparatus is changed to a predetermined method.   When the amount of toner in the invisible toner supply unit is less than a predetermined amount but is a printable amount, the image forming unit reduces the amount of invisible toner used in the code image forming method. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is changed to such a method.   The image forming apparatus according to claim 3, wherein the change to the method that reduces the amount of the invisible toner used is a change that widens an interval between unit images constituting the code image.   4. The image forming apparatus according to claim 3, wherein the change to the method that reduces the amount of the invisible toner used is a change that limits a type of information included in the code image.   4. The image forming apparatus according to claim 3, wherein the change to the method that reduces the usage amount of the invisible toner is a change to reduce an area of the area where the code image is printed.   When the invisible toner supply unit is not attached or when the toner amount in the supply unit is smaller than the printable amount, the image forming unit uses the invisible toner as the code image forming method. The image forming apparatus according to claim 1, wherein the image forming apparatus is changed to a non-existing method.   The image forming apparatus according to claim 7, wherein the method that does not use the invisible toner is a method that forms the code image with a specific visible toner.   9. The image forming apparatus according to claim 8, wherein the method of not using the invisible toner is a method of further forming the document image with another visible toner having a color distinguishable from the color of the specific visible toner. . Storage means for storing information on whether or not the invisible toner can be used for a plurality of image forming apparatuses including at least one image forming apparatus capable of printing a code image with invisible toner;
Receiving means for receiving a print instruction for a specific image forming apparatus among the plurality of image forming apparatuses;
When information indicating that the invisible toner cannot be used is stored for the specific image forming apparatus, the information indicating that the invisible toner can be used is stored with respect to the other image forming apparatus. A printing instruction apparatus comprising: a transmission unit that transmits a printing instruction. An image forming method in an image forming apparatus capable of forming a document image with visible toner and forming a machine-readable code image with invisible toner,
Detecting a defect in the supply of the invisible toner;
Forming the code image while maintaining the machine-readable state by a method corresponding to the detected invisible toner supply failure.

Images