JP2006039464A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely prevent the forgery of securities or a bill or the like while mitigating the inconvenience that output time is delayed because processing for discriminating an inhibited image is performed. <P>SOLUTION: When receiving an output instruction, processing for discriminating an image whether or not the inhibited image is included in the image to be outputted is started and also a motor is allowed to start recording paper feeding operation. When the result of discrimination that the inhibited image is included is obtained by the processing for discriminating the image thereafter, a transfer device is controlled so that a transfer process to recording paper may not be normally performed. Furthermore, the recording paper feeding operation is started before the start of the processing for discriminating the image, which is started according as required amount of image data is obtained by reading an original. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus having a function of preventing counterfeiting of securities and banknotes.

In recent years, the performance of image forming apparatuses such as copiers and printers has improved, and high image reproducibility has been obtained. Therefore, image forming apparatuses may be used for counterfeit purposes such as securities and banknotes. In order to prevent unauthorized use, an image pattern of a prohibited image that should be prevented from being counterfeited such as banknotes and securities is registered in advance, and when an output instruction is received, the prohibited image is included in the image to be output by comparing the image patterns. There is known a configuration in which a forbidden image is not output by performing a process for determining whether or not it is included (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2003-32489 (FIG. 2)

  However, in the conventional technique, when an output instruction is received, first, a determination process is performed to determine whether or not a prohibited image is included in an image to be output, and the determination process ends and no prohibited image is included. When the determination result is obtained, the recording paper feeding is started and the image forming process is executed, and the paper feeding and the image forming process are performed after waiting for the prohibited image determination result. It is effective in preventing counterfeiting reliably, but when trying to perform highly accurate discrimination processing, the output time will slow down as the time required for discrimination processing increases, and it will not be used illegally There is a problem that convenience in output processing is impaired.

  The present invention has been devised to solve such problems of the prior art, and its main purpose is to improve the inconvenience that output time is delayed due to the prohibition image discrimination processing, while reducing securities and banknotes. An object of the present invention is to provide an image forming apparatus configured to reliably prevent counterfeiting.

  In order to solve such problems, an image forming apparatus according to the present invention forms an image on a recording paper through each process in an exposure unit, a development unit, a transfer unit, and a fixing unit as described in claim 1. An image forming unit, a conveying unit that conveys a recording sheet on a conveying path from the sheet feeding unit to the sheet discharging unit via the transfer unit and the fixing unit, and whether or not a prohibited image is included in the image to be output An image discriminating unit for discriminating the image, and a control unit for controlling the image forming unit and the conveying unit based on the discrimination result of the image discriminating unit. When the control unit accepts an output instruction, When the discriminating unit starts the discriminating process, the transport unit starts the recording paper feeding operation from the paper feeding unit, and then the image discriminating unit obtains a discrimination result that the prohibited image is included, Image formation on the recording sheet is assumed for controlling said image forming means so as not to be successful.

  According to this, when a prohibited image is included in the image to be output, the prohibited image is formed incompletely on the recording paper, so that it is difficult to obtain what can actually be used for counterfeit purposes. Forgery of securities and banknotes can be reliably prevented. Since the paper feeding operation is executed in parallel with the image discrimination process, it is possible to avoid the disadvantage that the output time is significantly delayed for discrimination of the prohibited image.

  In this case, in order to control the image forming unit so that the image formation on the recording paper is not normally performed, at least one of the control conditions of the exposure unit, the developing unit, the transfer unit, and the fixing unit constituting the image forming unit is set. What is necessary is just to change significantly from the normal control state in which normal image formation is possible. Specifically, the supply of the control voltage may be stopped. Further, a configuration in which the control voltage is changed to a value different from the normal value is also possible.

  In the image forming apparatus, when the determination result that the prohibited image is included is obtained by the image determining unit, normal execution is prevented in each process of the image forming unit. An attention process is set in advance, the image determination unit ends the determination process before the attention process is started, and the control unit performs the attention process according to the determination result of the image determination unit. It is possible to adopt a configuration in which whether or not normal execution is possible is determined in advance. According to this, since the normal execution of the required attention process effective for preventing counterfeiting is prevented from the beginning, counterfeiting of securities and banknotes can be prevented more reliably.

  In the image forming apparatus, as shown in claim 3, the attention process may be a transfer process in the transfer unit. According to this, when the control unit obtains a determination result that the prohibited image is included by the image determining unit, the control unit controls the transfer unit so that the transfer process is not normally executed, and thereby the toner image of the prohibited image is partially However, forgery of securities or banknotes can be reliably prevented.

  According to a fourth aspect of the present invention, the process of interest may be a fixing process in the fixing unit. According to this, when the control unit obtains the determination result that the prohibited image is included by the image determining unit, the control unit controls the fixing unit so that the fixing process is not normally executed, and thereby the toner image of the prohibited image is partially Therefore, forgery of securities and banknotes can be reliably prevented.

  In addition, the present invention can be configured to control the exposure unit and the development unit so that the exposure process in the exposure unit and the development process in the development unit are not normally executed. If the image discrimination means obtains a determination result that the prohibited image is included, at least the fixing process is controlled so that the toner is removed even if the toner adheres to the recording paper. Accordingly, the recording paper can be reused, and it is possible to avoid the disadvantage that the recording paper is wasted because it is determined that the prohibited image is erroneously included for some reason.

  In the image forming apparatus, when the target process is an exposure process in the exposure unit and the image determination unit obtains a determination result that the prohibited image is included, the predetermined process is performed. The exposure means can be controlled such that the replacement image is formed on the recording paper. According to this, since the replacement image is formed on the recording paper in place of the original image including the prohibited image, it is possible to reliably prevent counterfeiting of securities and banknotes.

  In this case, the replacement image data is stored in the storage unit in advance, and the replacement image data is sent to the exposure unit in accordance with the determination result of the image determination unit that the prohibited image is included, and the exposure process is controlled normally. It can be done under conditions. In addition, the replacement image is not particularly limited, and a black image in which the entire area is filled with black, and an image in which characters and designs indicating that the replacement image is a forbidden image are drawn are preferable.

  In addition, the present invention can also be switched to a replacement image in the middle of the exposure process, and if it can be changed to a replacement image at an early timing after entering the exposure process, forgery can be substantially prevented. .

  In the image forming apparatus, as described in claim 6, the control unit requires the determination process of the image determination unit so that the attention process is started after the determination process by the image determination unit is completed. The determination required time can be predicted to control the start timing of feeding the recording paper from the paper feeding unit by the transport unit. According to this, even when the time required for determination varies according to the size of the image or the like, it is possible to reliably prevent normal execution of the predetermined process of interest from the beginning.

  In this case, the time required for the conveyance of the recording paper until the recording paper reaches the position corresponding to the start of the predetermined process after the conveyance unit starts the operation of feeding the recording paper from the paper supply unit is determined. The feeding start timing may be determined in comparison with the time required for determination in FIG. Each process of the image forming unit starts processing according to the position of the recording paper conveyed by the conveying unit, and the difference between the start timing of the process of interest and the determination processing end timing of the image determining unit is Adjust it with timing.

  In addition, the present invention omits the determination process of the image determination unit and the transfer operation of the transfer unit when the required determination time of the image determination unit is sufficiently shorter than the required transfer time to the target process start position of the recording paper. It is also possible to have a configuration that is set in advance so as to start simultaneously.

  Further, the recording paper is used until the end of the discrimination process of the image discriminating unit by using the conveyance adjusting unit that temporarily stops the progress of the recording paper, such as a registration roller that adjusts the conveyance timing of the recording paper and the image forming timing of the photosensitive member. It is good also as a structure which stops progress of this. In this case, in order to shorten the waiting time at the registration roller, the above-described feed start timing change control may be used in combination.

  The image forming apparatus further includes a reading unit that reads an image of a document, and the control unit starts processing in response to a required amount of image data being obtained by the reading unit. Prior to the start of the discrimination process of the image discrimination means, the paper feeding operation of the transport means can be started. According to this, when it takes time to transport the recording paper as compared with the determination processing of the image determining means, the output time can be shortened by starting the recording paper transporting operation early.

  In this case, the discrimination process of the image discriminating unit starts when the image data necessary for the discriminating process is acquired by reading the document image, and then the image data is sequentially generated by the reading operation by the reading unit. Accordingly, the discrimination process of the image discrimination means is continuously executed.

  In the image forming apparatus, as described in claim 8, even when the control unit obtains a determination result that the prohibited image is included by the image determination unit, the control is performed without stopping the operation of the transport unit. Thus, a recording paper incompletely formed with an image can be discharged to the paper discharge means.

  In this case, in the image forming unit, the toner image is partially formed by the process that has normally proceeded until the control change such as stopping the operation according to the determination result of the image determining unit. When the paper passes through the image forming means, the toner image may adhere to the recording paper. However, if the transfer or fixing is incomplete, forgery is substantially difficult.

  In the image forming apparatus, as described in claim 9, when the control unit obtains a determination result that the prohibited image is included by the image determination unit, the conveyance operation of the conveyance unit is stopped. The jam state can be adopted.

  In the image forming apparatus, as described in claim 10, when the control unit obtains a determination result that the prohibited image is included by the image determining unit, the main part of the apparatus including the image forming unit It can be set as the structure which stops the electric power feeding with respect to and terminates abnormally.

  In the present invention, as shown in claim 11, the image forming means for forming an image on the recording paper through the processes of the exposure means, the developing means, the transfer means and the fixing means, and the recording paper of the paper feeding means A paper feed path for feeding to the image forming means, a paper discharge path for discharging the recording paper that has passed through the image forming means to the paper discharging means, and a return path for sending the recording paper that has passed through the image forming means to the image forming means again. A conveying unit that conveys the recording paper on each path, a switching unit that guides the recording sheet that has passed through the image forming unit to one of the discharge path and the return path, and a prohibited image in the image to be output. An image discriminating unit that discriminates whether or not the image is included, and a control unit that controls the image forming unit and the conveying unit based on a discrimination result of the image discriminating unit. Excretion It is assumed that the determination process ends before the recording paper reaches the branch point with the path. When the control unit receives an output instruction, the control unit causes the image determination unit to start the determination process and causes the transport unit to execute the determination process. When the recording paper feeding operation from the paper feeding unit is started and then a determination result that the prohibited image is included is obtained by the image discrimination unit, the recording paper on which image formation is completed is guided to the return path. In this way, the switching means is controlled.

  According to this, when a prohibited image is included in the image to be output, it is possible to prevent the recording paper on which the prohibited image is formed from being discharged outside the machine, so that it is possible to counterfeit securities and banknotes. Can not be easily performed.

  In this case, the image discrimination means ends the discrimination process before the recording paper reaches the branch point between the return path and the discharge path.

  In the image forming apparatus, as described in claim 12, by feeding the recording paper introduced into the return path into the image forming unit, a separate image is forcibly formed on the back surface opposite to the surface on which the prohibited image is formed. It can be set as the structure which formed this. According to this, a recording sheet on which a prohibited image is formed on one side and another image is formed on the other side is discharged, and forgery of securities or banknotes, etc., which are usually given a predetermined print on both sides. Can be substantially blocked.

  In this case, the return path may be configured so as to return to the image forming unit with the front and back sides of the recording paper reversed.

  In the image forming apparatus, as described in claim 13, by feeding the recording paper introduced into the return path into the image forming unit, the other image is forcibly overwritten on the surface on which the prohibited image is formed. It can be set as the structure made into. According to this, another image is overwritten on the forbidden image formed on one surface of the recording paper, so that counterfeiting of securities or banknotes can be reliably prevented.

  In this case, the return path only needs to have a configuration in which the recording sheet is returned to the image forming unit without reversing the front and back of the recording sheet and the image is synthesized on one side of the recording sheet. Also, even if the return path is configured to return to the image forming means with the front and back sides of the recording paper reversed, if the recording paper sent from the return path to the image forming means is introduced into the return path again, the recording path The front and back sides of the paper are restored, and another image can be overwritten on one side of the recording paper.

  In addition, the present invention can also be configured to stop the processing when the recording paper is introduced into the return path, and in this case, the recording paper on the return path cannot be easily taken out mechanically. It ’s fine.

  Further, as described above, another image to be formed on the recording paper is not particularly limited, but a black image in which the entire area is filled with black, or an image in which characters or designs indicating that the image is prohibited is drawn is preferable. It is.

  Further, the discrimination processing of the image discriminating means is performed from the time required for transporting the recording paper to reach the branch point between the return path and the discharge path after the feeding means starts the feeding operation of the recording paper from the feeding means. When the time required for determination is short, the determination process of the image determination unit and the paper feed operation of the transport unit are started substantially simultaneously, or the paper feed operation of the transport unit is started prior to the determination process of the image determination unit. You may do it.

  In addition, the determination time required for the determination process of the image determination unit is predicted so that the recording sheet reaches the branch point after the determination process in the image determination unit is completed, and the recording sheet from the sheet supply unit by the transport unit is estimated. It may be configured to control the paper feed start timing. According to this, even when the required time for the determination is relatively long, the determination process is terminated before the recording paper reaches the branch point, and the recording paper is surely placed on the return path. Can be introduced.

  In addition, it is possible to adopt a configuration in which the progress of the recording paper is stopped until the end of the discrimination process of the image discrimination means by using a conveyance adjusting means such as a registration roller that temporarily stops the progress of the recording paper.

  In the image forming apparatus, as described in claim 14, the exposure unit and the development unit are provided for each color, and the transfer unit is an intermediate transfer unit that sequentially color-synthesizes toner images for each color. And a secondary transfer means for transferring the composite toner image carried by the intermediate transfer means onto a recording sheet.

  As described above, in the present invention, by performing irregular control in response to the determination result that the prohibited image is included by the image determining means, the normal output of the prohibited image is prevented. In such a configuration, starting the paper feeding operation immediately after receiving an output instruction without performing an operation such as shifting the paper feeding start timing as described above reduces the overall processing time. It is desirable to make the timing for switching to irregular control as late as possible to allow time for the discrimination processing in the image discrimination means. From this point of view, According to the eleventh aspect of the present invention, the configuration by the control of the switching means is optimal, and in the control for preventing the normal execution of the process of interest as in the second aspect, the subsequent stage such as fixing is performed. Configuration in which the process of interest process is preferred, thereby avoiding the delay of the output time by the discrimination processing of the prohibited image, it is possible to improve the usability of a normal output processing does not hit the unauthorized use.

  As described above, according to the present invention, when the prohibited image is included in the image to be output, the prohibited image is formed incompletely on the recording paper. This makes it difficult to counterfeit securities and banknotes. In addition, the paper feeding operation is executed in parallel with the image discrimination process, which greatly increases the output time for discrimination of prohibited images. Inconveniently, the image forming apparatus can be prevented from being used illegally, and the convenience of the image forming apparatus can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus to which the present invention is applied. The image forming apparatus includes an image forming unit (image forming unit) 1 that forms an image on recording paper through exposure, development, transfer, and fixing processes. The image forming unit 1 includes a paper feeding unit (feeding unit). The recording paper stored in the paper feed cassette 2 is sequentially fed through the paper feed path A, and the recording paper on which a required image is formed in the image forming unit 1 passes through the paper discharge path B and is discharged from the paper discharge unit. (Discharge means) The paper is discharged onto the tray 3.

  The image forming unit 1 forms a monochrome image on a recording sheet. The image forming unit 1 emits a light beam for exposure to the photosensitive drum 11 and an image forming surface of the photosensitive drum 11 uniformly charged by a charger (not shown). An LSU (laser scanning unit, exposure means) 12 that scans to form an electrostatic latent image, and a developer (development means) 13 that develops the electrostatic latent image on the image forming surface of the photosensitive drum 11 with toner. And a transfer device (transfer means) 14 for transferring the toner image formed on the image forming surface of the photosensitive drum 11 onto the recording paper, and a fixing device (for fixing the toner image on the recording paper to the recording paper by heat and pressure). Fixing means) 15.

  In addition, the image forming apparatus is provided with a return path C through which the recording paper sent from the image forming unit 1 is sent again to the image forming unit 1. In particular, here, the return path C constitutes the reversing unit 5, and the recording paper is returned to the image forming unit 1 with the front and back sides of the recording paper reversed by the switchback unit 58. Images can be formed on both sides. A switching member 51 is provided at a branch point between the paper discharge path B and the return path C to guide the recording paper sent from the image forming unit 1 to either the paper discharge path B or the return path C.

  The image forming apparatus further includes a document reading unit (reading unit) 4 that reads an image of a document, and image formation is performed by the image forming unit 1 based on image data acquired by the document reading unit 4. An original image can be copied on a recording sheet.

  FIG. 2 is a schematic diagram showing another example of an image forming apparatus to which the present invention is applied. Components having the same functions as those in the above example are denoted by the same reference numerals. The image forming apparatus includes an image forming unit 101 that forms a color image on recording paper. In the image forming unit 101, a plurality of photosensitive drums 111a to 111d for each primary color of CMYK are intermediate transfer belts (intermediate transfer belts (intermediate transfer belts)). (Transfer means) 115, and writing is performed on each of the photosensitive drums 111 a to 111 d by the LSU 112 and then developed by the developing rollers 113 a to 113 d, so that the photosensitive drums 111 a to 111 a are transferred. A toner image for each primary color is created on 111d, and the toner images for each primary color are sequentially transferred to the intermediate transfer belt 115 and combined to obtain a color image. The recording paper is fed between the intermediate transfer belt 115 and the secondary transfer roller (secondary transfer means) 114, and the color toner image is transferred to the recording paper. After the is discharged to the paper discharge unit 3 through the fixing device 15.

  This image forming apparatus is a so-called tandem type in which a plurality of image forming units for each primary color are arranged along an intermediate transfer belt 115 which is an intermediate transfer body. The present invention can also be applied to a so-called revolver type color image forming apparatus in which a plurality of image forming units for each primary color are arranged in the circumferential direction.

  FIG. 3 is a block diagram showing a schematic configuration of the image forming apparatus shown in FIG. Note that the image forming apparatus shown in FIG. 2 has substantially the same configuration. In this image forming apparatus, the detection result of the registration sensor 18 of the image forming unit 1 is sent to the main control unit (control means) 9 via the image formation control unit 16, and the main control unit 9 performs the LSU 12 and the developing unit 13. The transfer device 14 and the fixing device 15 are controlled. The main controller 9 controls a registration roller 19 that aligns the latent image on the photoconductor and the recording paper, a main motor (conveying means) 17 that drives the rollers of the photoconductor drum 11 and the fixing device 15. .

  In the paper feed unit 2, the detection result of the paper feed sensor 21 is sent to the main control unit 9 via the paper feed control unit 23, and a paper feed motor that drives a roller to transport the recording paper on the paper feed path A (Conveying means) 22 is controlled by the main controller 9. In the paper discharge unit 3, a detection result of the paper discharge sensor 31 is sent to the main control unit 9 via the paper discharge control unit 33, and a paper discharge motor that drives a roller to transport the recording paper on the paper discharge path B (Conveying means) 32 is controlled by the main controller 9. In the document reading unit 4, a detection result of the document sensor 41 is sent to the main control unit 9 via the document reading control unit 44, and a reading unit 43 including a line sensor for reading a document image, and a reading surface of the reading unit 43. The main motor 9 controls the transport motor 42 that transports the original document.

  In the reversing unit 5, the switching drive unit 52 that drives the switching member 51 that switches between the paper discharge path B and the return path C is controlled by the main control unit 9 via the reversal control unit 56. The detection results of the entry sensor 53 and the discharge sensor 54 are sent to the main control unit 9, and a conveyance motor (conveying means) 55 that drives a roller to convey the recording paper on the return path C is controlled by the main control unit 9. Is done.

  Further, the image forming apparatus includes an image determination unit (image determination unit) 6 that determines whether or not a prohibited image that is prohibited from being copied, such as banknotes or securities, is included in an image to be output. In order to prevent the forbidden image from being formed on the recording paper, the main control unit 9 is based on the determination result of the image determination unit 6, the transfer unit 14 and the fixing unit 15 of the image forming unit 1, and motors provided in the respective units. And so on. In the image discriminating unit 6, image data generated by the line sensor of the reading unit 43 is stored in the print image storage unit 61, and print image storage is performed using a technique such as pattern matching based on the prohibition image data in the prohibition image storage unit 62. The determination processing unit 63 performs processing for determining whether the image data of the unit 61 includes a prohibited image.

  When the main control unit 9 receives an output instruction by operating the start button on the operation panel 8, the main control unit 9 starts reading the document image by the document reading unit 4 and then causes the image determination unit 6 to start the determination process. At the same time, when the paper feeding motor 22 starts the recording paper feeding operation from the paper feeding unit 2 and then obtains a discrimination result that the prohibited image is included by the image discrimination unit 6, the image formation on the recording paper is normal. The image forming unit 1 is controlled so as not to be executed. Thus, the image forming apparatus shown in FIG. 1 can prevent counterfeiting of black and white securities, and the image forming apparatus shown in FIG. 2 can prevent counterfeiting of color securities and banknotes.

  In particular, here, as will be described in detail below, when the image determination unit 6 determines that a prohibited image is included, the image forming unit 1 performs the exposure, development, transfer, and fixing processes. In this way, the main process unit 9 sets the attention process that prevents normal execution in advance, and the image determination unit 6 ends the determination process before the attention process is started. Whether or not normal execution in the process of interest is possible is determined in advance according to the determination result.

  FIG. 4 is a timing chart showing an example of the control procedure in the image forming apparatus shown in FIG. 1, where (A) shows a normal case where a prohibited image is not detected, and (B) shows a case where a prohibited image is detected. Each is shown. Here, the attention process that prevents normal execution when the image determination unit 6 obtains a determination result that a prohibited image is included is the transfer process in the transfer device 14, and the recording paper is the transfer device. 14, before the transfer process at 14 is completed, the determination process of the image determination unit 6 is completed, and when the determination result that the prohibited image is included is obtained by the image determination unit 6, the transfer process is performed as shown in FIG. The transfer unit 14 is controlled so as not to execute normally. In the example shown in FIG. 2, the secondary transfer roller 114 is controlled in order to prevent the secondary transfer roller 114 from properly executing the secondary transfer process of transferring the toner image from the intermediate transfer belt 115 to the recording paper. It ’s fine.

  Further, here, prior to the start of the discrimination process in the image discriminating unit 6 which starts the processing in response to the required amount of image data being obtained by the document reading unit 4, the recording from the paper feed unit 2 by the paper feed motor 22 is performed. The paper feeding operation is started, and the time required for conveyance until the recording paper arrives at a position corresponding to the start of the predetermined attention process, that is, the transfer process after starting the paper feeding operation is Even if it is longer than the required determination time required for the determination process in the determination unit 6, the determination process in the image determination unit 6 can be ended before the recording paper reaches the start position of the transfer process.

  Further, here, even when the determination result that the prohibited image is included is obtained by the image determination unit 6, the operation of the main motor 17 and the paper discharge motor 32 is controlled without stopping, so that the image formation is incomplete. The paper is discharged out of the apparatus by the paper discharge unit 3.

  Further, here, the respective processes of the exposure by the LSU 12 and the development by the developing unit 13 which have already been started when the determination result of the image determination unit 6 is obtained are continued as they are. It is also possible to adopt a configuration in which these processes are stopped halfway by stopping the supply of control voltage to the LSU 12 and the developing device 13 at the obtained stage. Further, a configuration in which the fixing process by the fixing device 15 at the latter stage of the transfer process is not started is possible.

  In this case, even if the execution of the transfer process is blocked according to the determination result of the image determination unit 6, the toner image of the read image is partially formed on the photosensitive drum 11, and as described above, the recording paper In the configuration of discharging the toner, when the recording paper passes between the photosensitive drum 11 and the transfer device 14, the toner adheres to the recording paper due to contact with the toner image formed on the photosensitive drum 11. Since the toner image is not normally transferred, it is extremely difficult to obtain a toner image that can be actually used for counterfeit purposes.

  In order to prevent the normal execution of the transfer process, for example, in the case of a transfer charger that moves charged toner particles on a photosensitive member onto a transfer member (such as a recording paper or an intermediate transfer member) by a bias voltage, the operating voltage is set to It may be cut off so as not to generate a bias voltage. If the transfer means is constituted by a transfer roller, in addition to or in addition to stopping the bias voltage, in the example shown in FIG. 1, the nip of the transfer roller with respect to the photosensitive drum 11 is released. In the example shown in FIG. 2, the normal execution of the transfer process may be prevented by releasing the nip of the transfer roller 114 with respect to the intermediate transfer belt 115.

  In addition, when the determination result that the prohibition image is included is obtained by the image determination unit 6, the conveyance operation of the main motor 17 may be stopped and the jammed state may be set. In this case, in order to restore the apparatus, it is necessary to take out the recording paper causing the jam.

  Further, when the determination result that the prohibited image is included is obtained by the image determination unit 6, the power supply to the main part of the apparatus including the image forming unit 1 may be stopped and abnormally terminated. In this case, it is necessary to turn the power on again to restore the device.

  FIG. 5 is a flowchart showing a processing procedure in the control procedure shown in FIG. Here, first, at step 101, the paper feed motor 22 is activated to start conveyance of the recording paper, and at step 102, the reading unit 43 and the conveyance motor 42 of the original reading unit 4 are activated to perform the original reading process. Let it begin. Next, when it is detected in step 103 that the document reading process has started and the required amount of image data has been accumulated, in step 104, the discrimination process in the image discrimination unit 6 is started.

  If it is detected in step 105 that the image discrimination processing has been completed, and if the discrimination result in the image discrimination unit 6 indicates that there is no prohibited image in step 106, the routine proceeds to step 107 and the recording paper is required. It is determined whether or not the transfer position is reached and the transfer is ready. If the transfer is ready, the process proceeds to step 108 and the transfer unit 14 is activated to start the transfer process. Next, when the end of the transfer process to the recording paper is detected in step 109, the transfer unit 14 is stopped in step 110 to end the transfer process, and further in step 111, the conveyance of the recording paper is completed. If detected, the main motor 17 and the paper discharge motor 32 are stopped at step 112.

  On the other hand, if the determination result in the image determination unit 6 indicates that there is a prohibited image in step 106, the process proceeds to step 111 where the recording paper is passed without starting the transfer device 14 and the recording paper is removed from the machine. To be discharged.

  FIG. 6 is a timing chart showing another example of the control procedure in the image forming apparatus shown in FIG. 1. In FIG. 6, (A) shows a normal case where a prohibited image is not detected, and (B) shows a prohibited image detected. Each case is shown. Here, the attention process that prevents normal execution when the image determination unit 6 determines that a prohibited image is included is the fixing process in the fixing device 15, and the recording paper is the fixing device. When the determination process of the image determination unit 6 is completed before entering the fixing process at 15, and the determination result that the prohibited image is included is obtained by the image determination unit 6, the fixing process is performed as shown in FIG. The fixing device 15 is controlled so as not to be executed normally. In the case of the image forming apparatus shown in FIG. 2, the fixing device 15 may be similarly controlled.

  In this case, when the discrimination result of the image discrimination unit 6 is obtained, the exposure process by the LSU 12, the development process by the developing unit 13, and the transfer process by the transfer unit 14 have already been started, and the toner image of the read image is transferred onto the recording paper. However, if fixing is incomplete, it is difficult to obtain one that can be actually used for counterfeit purposes.

  In order to prevent the normal execution of the fixing process, for example, it is only necessary not to apply an operating voltage to the heater that constitutes the fixing device 15, and this does not cause a temperature state necessary for fixing. It becomes. Further, if the fixing device 15 is configured to be able to release the nip between both the heating and pressure rollers, the nip is released, so that the pressure state necessary for fixing is not obtained, so that the fixing is incomplete.

  FIG. 7 is a timing chart showing another example of the control procedure in the image forming apparatus shown in FIG. 1, where (A) shows a normal case where no prohibited image is detected, and (B) shows a prohibited image detected. Each case is shown. Here, the determination required time required for the determination process of the image determination unit 6 is predicted so that the transfer process, which is the process of interest, is started after the determination process in the image determination unit 6 is completed. The start timing of feeding the recording paper from the paper unit 2 is controlled. The image forming unit 1 starts each process in accordance with the position of the recording paper conveyed by the paper feeding motor 22 and the main motor 17 and shifts the recording paper feeding start timing. Immediately after the discrimination processing is completed, the recording paper can enter the transfer process.

  In this case, the main control unit 9 performs a process of calculating the required time for determination by the image determination unit 6 based on the document size detected by the document reading unit 4, and the recording paper size designated by the operation panel 8. It is necessary to start the recording paper feeding operation by the paper feeding motor 22 based on the position of the paper feeding cassette 2 or the manual feed tray of the paper feeding unit 2 corresponding to the time until the recording paper reaches the transfer process start position. The required conveyance time is acquired, and a process of calculating a waiting time for delaying the paper feed start timing is performed based on the required determination time and the required conveyance time.

  FIG. 8 is a flowchart showing a processing procedure in the control procedure shown in FIG. Here, first, in step 201, a process for calculating a waiting time for defining the paper feed start timing is performed by the main control unit 9, and then in step 202, the reading process in the document reading unit 4 is started. When it is detected that the document reading process is started, the discrimination process in the image discrimination unit 6 is started in step 204. If it is determined in step 205 that the paper feed start timing has come, the routine proceeds to step 206, where the paper feed motor 22 is activated to start transporting the recording paper. Thereafter, steps 207 to 214 are executed in the same manner as steps 105 to 112 in the example shown in FIG.

  FIG. 9 is a timing chart showing another example of the control procedure in the image forming apparatus shown in FIG. 1, where (A) shows a normal case where no prohibited image is detected, and (B) shows a prohibited image detected. Each case is shown. Here, the attention process that prevents normal execution when the image determination unit 6 determines that a prohibited image is included is an exposure process in the LSU (exposure means) 12. When the determination process of the image determination unit 6 is completed before the recording paper reaches the position at which the transfer process starts, and the determination result that the prohibited image is included by the image determination unit 6 is obtained, as shown in FIG. As described above, the LSU 12 is controlled so that the exposure process is not normally executed. Specifically, the replacement image data prepared in advance is sent to the LSU 12 and the exposure with the replacement image is performed. In the case of the image forming apparatus shown in FIG. 2, the LSU 112 may be similarly controlled.

  In this case, the timing at which the discrimination process at the image discrimination unit 6 is completed is relatively early, so that the recording paper reaches a position corresponding to the start of the exposure process after the discrimination process at the image discrimination unit 6 is completed. In addition, it is preferable to delay the recording paper feed start timing in the same manner as in the example shown in FIG.

  FIG. 10 is a flowchart showing a processing procedure in the control procedure shown in FIG. Here, steps 301 to 307 are executed in the same manner as steps 201 to 207 in the example shown in FIG. If the determination result in the image determination unit 6 indicates that there is a prohibited image in step 308, the process proceeds to step 309, where a replacement image different from the read image is prepared for exposure, and in step 310, the LSU 12 To start the exposure process. On the other hand, if the determination result in the image determination unit 6 indicates that there is no prohibited image in step 308, the exposure process is started in step 310 with the read image as it is.

  Next, when it is detected in step 311 that the exposure process has been completed, the LSU 12 is stopped in step 312 to end the exposure process, and then in step 313 it is detected that the conveyance of the recording paper has been completed. In step 314, the main motor 17 and the paper discharge motor 32 are stopped.

  FIG. 11 is a timing chart showing another example of the control procedure in the image forming apparatus shown in FIG. 1. In FIG. 11, (A) shows a normal case where a prohibited image is not detected, and (B) shows a prohibited image detected. Each case is shown. Here, it is assumed that the image determination unit 6 ends the determination process before the recording paper reaches the branch point between the return path C and the paper discharge path B, and the main control unit 9 sets the start button on the operation panel 8. When the output instruction is received by the operation of, the reading of the document image by the document reading unit 4 is started, the image determination unit 6 starts the determination process, and the sheet feed motor 22 is fed from the sheet feed unit 2. When the recording paper feeding operation is started and then a determination result that the prohibited image is included is obtained by the image determination unit 6, switching is performed so that the recording paper on which image formation is completed is introduced into the return path C. A switching drive unit (switching means) 52 that drives the member 51 is controlled.

  FIG. 12 is a flowchart showing a processing procedure in the control procedure shown in FIG. Here, Steps 401 to 407 are executed in substantially the same manner as Steps 101 to 106 in the example shown in FIG. 5. In particular, here, in Step 402, the transfer device 15 and the like of the image forming unit 1 are previously set. Each process of exposure, development, transfer and fixing is executed according to the progress of the recording paper.

  If the determination result in the image determination unit 6 indicates that there is no prohibited image in step 407, the switching drive unit 52 is operated in step 408 to switch the destination to the outside of the apparatus. In step 409, the discharge motor 32 is activated to discharge the recording paper to the outside of the apparatus. In step 410, when it is detected that the discharging process of the recording paper has been completed, step 411 is performed. The paper discharge motor 32 is stopped at. In step 412, the main motor 17 is stopped, and in step 413, the operation of the image forming unit 1 such as the transfer unit 15 is stopped.

  On the other hand, if the determination result in the image determination unit 6 indicates that there is a prohibited image in step 407, the process proceeds to step 414 to perform processing for switching the recording paper destination to the return path C, and then to step 415. Then, the conveyance motor 55 is activated to store the recording paper in the return path C. When it is detected in step 416 that the recording paper has been stored in the return path, the transport motor 55 is stopped in step 417 and the process proceeds to step 412.

  Here, as described above, the return path C constitutes the reversing unit 5 that returns the recording paper to the image forming unit 1 with the front and back sides of the recording paper being reversed. The recording paper introduced into the path C may be sent again to the image forming unit 1 to forcibly form another image on the back side of the surface on which the prohibited image is formed. In addition, when the recording paper sent from the return path C to the image forming unit 1 is once again introduced into the return path C and turned upside down and sent to the image forming unit 1, a forbidden image is formed. It is possible to overwrite another image on the surface.

  Further, if the return path C can return the recording paper to the image forming unit 1 without inverting the front and back of the recording paper, the prohibited image is sent again by sending the recording paper to the image forming unit 1. Another image can be forcibly overwritten on the surface on which is formed. For example, in the example shown in FIG. 1, if a path for guiding the recording sheet guided to the return path C by the switching member 51 to the return path C without being drawn into the switchback portion 58 is provided, The recording paper can be returned to the image forming unit 1 without inverting the front and back.

  In this case, since the timing at which the discrimination process in the image discrimination unit 6 is finished may be relatively late, if the required time for discrimination is relatively short, as shown in FIG. 11, the feed is performed prior to the image discrimination process. The paper operation may be started. However, if the required time for the determination is relatively long, the recording paper reaches the branch point between the return path and the discharge path after the determination process in the image determination unit 6 is completed. In addition, it is preferable to control the recording paper feed start timing by predicting the time required for determination by the image determination unit 6.

  The example of the copying machine including the image forming unit and the document reading unit has been described above. However, the present invention is not limited to this, and for example, an external information processing apparatus (for example, a PC) is used instead of the document reading unit. A printer that receives print data from the printer or the like and performs image forming processing, or a multi-function machine having both functions is also possible. In this case, the discrimination target of the image discrimination means is image data received from the outside.

  The image forming apparatus according to the present invention has an effect of reliably preventing counterfeiting of securities and banknotes while improving the inconvenience that output time is delayed due to the prohibited image discrimination processing, and counterfeits such as securities and banknotes. It is useful as a copying machine, a printer, a multi-function machine, etc., which are image forming apparatuses having a function to prevent.

Schematic diagram showing an example of an image forming apparatus to which the present invention is applied. Schematic diagram illustrating another example of an image forming apparatus to which the present invention is applied. 1 is a block diagram showing a schematic configuration of the image forming apparatus shown in FIG. FIG. 1 is a timing diagram illustrating an example of a control procedure in the image forming apparatus illustrated in FIG. 1. The flowchart which shows the procedure of the process in the control point shown in FIG. FIG. 3 is a timing chart showing another example of the control procedure in the image forming apparatus shown in FIG. FIG. 3 is a timing chart showing another example of the control procedure in the image forming apparatus shown in FIG. The flowchart which shows the procedure of the process in the control point shown in FIG. FIG. 3 is a timing chart showing another example of the control procedure in the image forming apparatus shown in FIG. The flowchart which shows the procedure of the process in the control point shown in FIG. FIG. 3 is a timing chart showing another example of the control procedure in the image forming apparatus shown in FIG. The flowchart which shows the procedure of the process in the control point shown in FIG.

Explanation of symbols

1 Image forming unit (image forming means)
2 Paper feed unit (paper feed means)
3 Paper discharge section (paper discharge means)
4 Document reading section (reading means)
5 Inversion unit 6 Image discrimination unit (image discrimination means)
9 Main control unit (control means)
11 Photosensitive drum 12 LSU (exposure means)
13 Developer (Developer)
14 Transfer device (transfer device)
15 Fixing device (fixing means)
17 Main motor (conveying means)
22 Paper feed motor (conveying means)
32 Paper discharge motor (conveyance means)
51 switching member 52 switching drive part (switching means)
55 Conveyance motor (conveyance means)
101 Image forming units 111a to 111d Photosensitive drum 112 LSU (exposure means)
113a to 113d Developing roller (developing means)
114 Secondary transfer roller (transfer means)
115 Intermediate transfer belt A Paper feed path B Paper discharge path C Return path

Claims (14)

An image forming unit that forms an image on a recording sheet through each process in an exposure unit, a developing unit, a transfer unit, and a fixing unit;
A transport unit that transports the recording paper on a transport path from the paper feed unit to the paper discharge unit via the transfer unit and the fixing unit;
Image discriminating means for discriminating whether or not a prohibited image is included in an image to be output;
Control means for controlling the image forming means and the conveying means based on the result of discrimination by the image discrimination means,
When the control unit accepts an output instruction, the image determination unit starts the determination process, and the conveyance unit starts the recording paper feeding operation from the paper supply unit, and then the image determination unit. When the determination result that the prohibited image is included is obtained, the image forming apparatus controls the image forming unit so that the image formation on the recording paper is not normally executed.   When the image determination unit obtains a determination result that the prohibited image is included, a process of interest that prevents normal execution is set in advance in each process of the image forming unit, and the image determination unit The discriminating process is terminated before the attention process is started, and the control means determines in advance whether or not normal execution in the attention process is possible according to the discrimination result of the image discrimination means. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 2, wherein the process of interest is a transfer process in the transfer unit.   The image forming apparatus according to claim 2, wherein the attention process is a fixing process in the fixing unit.   The exposure process is such that the predetermined replacement image is formed on the recording paper when the attention process is an exposure process in the exposure unit and the image determination unit obtains a determination result that the prohibited image is included. The image forming apparatus according to claim 2, wherein the image forming apparatus is controlled.   The control unit predicts a determination required time required for the determination process of the image determination unit so that the attention process is started after the determination process in the image determination unit is completed, and the sheet feeding by the transport unit is performed. The image forming apparatus according to claim 2, wherein the timing for starting the feeding of the recording paper from the means is controlled. A reading unit for reading an image of the document;
The control means starts the paper feeding operation of the transport means prior to the start of the discrimination processing of the image discrimination means that starts processing in response to the required amount of image data being obtained by the reading means. The image forming apparatus according to claim 1.   Even when the control unit obtains a determination result that the prohibited image is included by the image determination unit, the control unit performs control without stopping the operation of the transport unit, and removes the recording paper with incomplete image formation. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is discharged by a paper unit.   2. The control unit according to claim 1, wherein when the control unit obtains a determination result that the prohibited image is included by the image determination unit, the conveyance unit stops the conveyance operation and enters a jam state. The image forming apparatus described.   When the control unit obtains a determination result that the prohibited image is included by the image determining unit, the power supply to the main part of the apparatus including the image forming unit is stopped and abnormally terminated. The image forming apparatus according to claim 1. An image forming unit that forms an image on a recording sheet through each process in an exposure unit, a developing unit, a transfer unit, and a fixing unit;
A paper feed path for feeding the recording paper of the paper feed means to the image forming means, a paper discharge path for discharging the recording paper that has passed through the image forming means to the paper discharge means, and the recording paper that has passed through the image forming means are again Conveying means for conveying the recording paper on each of the return paths to be sent to the image forming means;
Switching means for guiding the recording paper that has passed through the image forming means to either the paper discharge path or the return path;
Image discriminating means for discriminating whether or not prohibited images are included in the image to be output;
Control means for controlling the image forming means and the conveying means based on the discrimination result of the image discrimination means,
The image determination means ends the determination process before the recording paper reaches the branch point between the return path and the discharge path;
When the control unit accepts an output instruction, the image determination unit starts the determination process, and the conveyance unit starts the recording paper feeding operation from the paper supply unit, and then the image determination unit. When the determination result that the prohibited image is included is obtained, the image forming apparatus controls the switching unit so that the recording paper on which image formation is completed is guided to the return path.   12. The recording paper introduced into the return path is sent to the image forming means to forcibly form another image on the back surface opposite to the surface on which the prohibited image is formed. The image forming apparatus described in 1.   12. The image according to claim 11, wherein another image is forcibly overwritten on the surface on which the prohibited image is formed by feeding the recording paper introduced into the return path into the image forming unit. Forming equipment. The exposure unit and the developing unit are provided for each color, and the transfer unit is an intermediate transfer unit that sequentially transfers and color-combines toner images for each color, and a composite toner image carried on the intermediate transfer unit The image forming apparatus according to claim 1, further comprising a secondary transfer unit that transfers the image to a recording sheet.