JP4654988B2 - Image processing apparatus and program - Google Patents

Description

  The present invention relates to a technique for erasing data in an image processing apparatus.

  For example, an image forming apparatus such as a copying machine, a printer, or a facsimile receives image data representing a document read by the image reading apparatus or image data sent via a communication line such as a LAN (Local Area Network). Temporarily store in a large-capacity non-volatile storage device such as (HDD), read image data from the storage device as appropriate, perform predetermined image processing, and then form an image represented by the image data on recording paper To do. Even after such an image forming operation is completed, the image data is often stored in a storage device. That is, even when the image data stored in the storage device is erased, in general, only management information associated with the data is deleted, and the image data itself is stored in the storage device. It is left behind. Recently, it has been pointed out that this image data may be read illegally by a malicious third party.

Thus, techniques for appropriately erasing data stored in the storage device have been proposed (for example, Patent Documents 1 to 4). For example, Patent Document 1 proposes a technique for erasing data at a timing at which the influence of the apparatus on other processing such as a standby state becomes relatively small. Further, according to the technique disclosed in Patent Document 2, it is possible to select an erasing method such as the number of erasures, encoding, and data retention according to data. Patent Document 3 proposes a technique for changing the number of times of erasure according to data. Patent Document 4 proposes a technique for performing erasure processing in the order of security levels of image data.
JP-A-9-284572 JP 2003-32484 A JP 2004-153516 A JP 2005-159550 A

  The present invention has been made in view of such circumstances, and an object thereof is to provide a mechanism for appropriately erasing data stored in a storage means.

  In order to solve the above-described problem, the first configuration of the present invention is a data erasure that erases the image data from the storage area by writing data different from the image data to the storage area in which the image data is stored. When the process is repeated a plurality of times, an allocating unit that assigns a priority to each of the plurality of data erasing processes, and the plurality of data erasing processes for the first image data are each erased by the allocating unit. A first erasing unit that executes in order according to the priority assigned to the process, and a plurality of times of data erasing processing for second image data different from the first image data are erased by the allocating unit. A second erasing unit that executes in order according to the priority assigned to the process; If a data erasure process is requested for the second image data while any one of a plurality of data erasure processes is being executed, the data erasure process executed by the first erasure means The priority is compared with the priority for the data erasing process that has not yet been executed by the first erasing means and the priority assigned to each of the plurality of data erasing processes for the second image data, Control means for determining the order of execution according to the priority of the data erasing process, and controlling the first erasing means or the second erasing means to execute the data erasing process according to the determined order Device.

  Further, the second configuration is to repeat a data erasing process for erasing the image data from the storage area by writing data different from the image data to the storage area in which the image data is stored. Assigning a priority to each of these multiple data erasure processes, assigning a priority to a process other than the data erasure process for the image data, and the multiple data erasure processes for the image data. , An erasing unit that executes in order according to the priority assigned to each data erasing process by the allocating unit, and a process other than the data erasing process for the image data is executed in order according to the priority assigned by the allocating unit One of the plurality of data erasing processes is executed by the executing means and the erasing means. When a process other than the data erasing process is requested for the image data, the priority for the data erasing process executed by the erasing unit and the data erasing process not yet executed by the erasing unit The priority is compared with the priority assigned to each of the processes other than the data erasing process for the image data, the order of execution is determined according to the priority for each process, and the erasing means or An image processing apparatus comprising control means for controlling the processing means to execute processing.

  In a third configuration, a confidentiality storage unit that stores a predetermined confidentiality and a priority for each of the plurality of data erasing processes in association with each other in the first configuration and the second configuration. And a confidentiality designation unit that designates the confidentiality, and the assigning unit assigns the priority stored in the confidentiality storage unit in association with the confidentiality designated by the confidentiality designation unit.

  Further, the fourth configuration includes keyword storage means for storing the keyword and the priority for each of the plurality of data erasing processes in association with each other in the first configuration and the second configuration, The assigning means extracts a keyword from a character image included in an image represented by the image data, and assigns a priority stored in the keyword storage means in association with the extracted keyword.

  Further, in the fifth configuration, in the first configuration and the second configuration, a pseudo image storage unit that stores predetermined image data as pseudo image data is provided, and the data erasure is performed multiple times on the image data. The data erasure process executed last among the processes is a process for writing the pseudo image data stored in the pseudo image storage means to the storage area.

  According to a sixth configuration, there is provided a determination unit that determines whether or not the image data is encrypted in the fifth configuration, and the first and second control units are configured to perform the determination by the determination unit. If it is determined that the image data is encrypted, the last data erasure process of the plurality of data erasure processes for the image data is executed by the pseudo image storage means. This is a process of writing image data or random numbers into the storage area and encrypting them.

  According to a seventh configuration of the present invention, a data erasure process is performed to erase the image data from the storage area by writing data different from the image data to the storage area in which the image data is stored in the computer. When repeating a plurality of times, an assignment function for assigning a priority to each of the plurality of data erasure processes and a plurality of data erasure processes for the first image data are assigned to each data erasure process by the assignment function. A first erasing function that is executed in order according to the assigned priority and a plurality of times of data erasing processing for second image data different from the first image data are assigned to each data erasing processing by the allocating function. A second erasing function that executes in order according to the assigned priority, and the first image data by the first erasing function; When data erasure processing for the second image data is requested while any one of several times of data erasure processing is executed, the data erasure processing executed by the first erasure function is executed. The priority is compared with the priority for the data erasing process that has not yet been executed by the first erasing function, and the priority assigned to each of the plurality of data erasing processes for the second image data, A program for realizing a control function for determining an execution order according to the priority of the data erasing process and controlling the first erasing function or the second erasing function to execute the data erasing process according to the determined order It is.

  Further, in the eighth configuration, data erasure processing for erasing the image data from the storage area by writing data different from the image data in the storage area in which the image data is stored in the computer is repeated a plurality of times. And assigning a priority to each of the plurality of times of data erasing processing, and assigning a priority to processing other than the data erasing processing for the image data, and the plurality of times of data for the image data An erasing function that executes the erasing process in order according to the priority assigned to each data erasing process by the allocation function, and processes other than the data erasing process for the image data in order according to the priority assigned by the allocation function An execution function to be executed and a plurality of data erasure processes by the erasure function If any process other than the data erasure process is requested while the image data is being executed, the priority for the data erasure process being executed by the erasure function and the process still being executed by the erasure function The priority for the non-data erasure process is compared with the priority assigned to each of the processes other than the data erasure process for the image data, and the execution order is determined according to the priority for each process. And a control function for controlling the erasing function or the processing function to execute the process according to the program.

According to the first and seventh configurations of the present invention, it is possible to execute a plurality of data erasing processes on the first and second image data according to the priority.
Further, according to the second and eighth configurations of the present invention, a plurality of data erasing processes for image data and processes other than the data erasing processes can be executed according to priority.
According to the third configuration, the priority can be set by designating the security level.
According to the fourth configuration, the security level can be set according to the keyword in the image data, and the priority can be set.
According to the fifth configuration, since the data erasing process is completed in a state where the pseudo image data is written, even if a third party refers to the storage area, it is determined which data is important data. It becomes difficult.
According to the sixth configuration, since the pseudo image is also encrypted, the risk of information leakage can be reduced.

(1) Device Configuration FIG. 1 is a block diagram showing a configuration of an image processing device 1 according to the present embodiment. The image processing apparatus 1 is realized by an apparatus having, for example, a printout function, a scan (image reading) function, a copy (copying) function, and a facsimile function. As shown in FIG. 1, an image processing apparatus 1 includes a CPU (Central Processing Unit) that controls the entire apparatus, a RAM (Random Access Memory) that provides a work area for work, and a ROM (Read Only) that stores various control programs. Interface device for performing communication via a control unit 11 including a memory), an operation unit 12 such as various buttons and a touch panel type liquid crystal display, and a communication unit such as an intranet or a LAN (Local Area Network). A communication unit 13, an image reading unit 14 that reads an image from a document, an image forming unit 15 that forms an image on a recording sheet (medium), and a program and various data describing operation procedures performed by the control unit 11 Is stored, and a display unit 17 such as a liquid crystal display for displaying various types of information is provided. The storage unit 16 is a non-volatile storage medium, for example, an HDD that stores data by a magnetic storage method.

  When the user operates the operation unit 12 to instruct copying (copying) of a document, for example, the control unit 11 instructs the image reading unit 14 to read an image. In response to this instruction, the image reading unit 14 emits light to a document placed on a platen glass (not shown), optically reads an image of the document, generates image data, and supplies the image data to the control unit 11. To do. The control unit 11 stores this image data in the storage unit 16. When the communication unit 13 receives the image data, the control unit 11 stores the image data in the storage unit 16. The control unit 11 appropriately reads out the image data stored in the storage unit 16 in this way and supplies it to the image forming unit 15 to form an image on the recording sheet.

(2) Data Erasing Method When such an image forming process is completed, the control unit 11 is configured to execute an erasing process for erasing the image data from the storage unit 16. Hereinafter, the storage area in which the erasure process is executed by the control unit 11 is referred to as “erase area”. Specifically, this erasing process is an overwriting type erasing process in which data different from the image data is written in the erasing area. Specifically, the control unit 11 overwrites “0” (zero) according to the address from the start address to the end address of the erase area (referred to as zero method), for example, “0x00” or “0xff” Overwrite such random numbers (called random number method).

  However, when erasing data, vibration occurs due to the rotation of the hard disk, etc., and further, the magnetic head is displaced by the vibration, resulting in residual magnetism, and an area where image data is not erased occurs in the erase area. There is a case. Therefore, the control unit 11 performs the above-described overwrite erasure process a plurality of times (three times in the present embodiment) on the erasure area. This is because the probability of successful data erasure increases as the number of overwriting processes increases.

By the way, in a method of erasing image data by overwriting data different from image data, such as the above-described “zero method” or “random number method”, a storage area where image data has not been erased is assigned by a third party. There is a risk of being identified. The reason will be explained.
FIG. 2A shows an example of the data structure of the storage area M when the erase process is performed by the “zero method”. In FIG. 2A, the storage area in which a value other than “0” zero is written is indicated by hatching (the same applies to FIGS. 2B and 2C). In the case of this method, the storage area in which data “0” is written is not only the erase area 16b but also an unused area 16d in which data has never been written. On the other hand, the storage areas in which values other than “0” zero are written include a management information area 16a in which management information of image data in a file format is stored, and an image data area in which image data other than erased image data is stored. It is limited to 16c. Therefore, if a malicious third party specifies an area in which data other than “0” is written, some information is written in that area, so that information is temporarily encrypted. Even if security measures such as the above are taken, the risk of browsing the information becomes high. On the other hand, even in the erasure area 16b, there is a possibility that data may remain due to the above-described residual magnetism. Data may be read out.

  Next, FIG. 2B shows an example of the data structure of the storage area when the erasing process is performed by the “random number method”. In this method, the storage area in which “0” is written is limited to the unused area 16d. Therefore, the storage area in which a value other than “0” is written is the management information area 16a, the erase area 16b, and the image data area 16c which are shaded in the figure, where the image data is stored or where the image data is stored. It becomes difficult to specify whether data has been stored. Therefore, it can be said that the risk of information leakage is reduced as compared with the case of the “zero method” in FIG. However, management information of image data is stored in the management information area 16a, and this management information may include characteristic values of the image data. Therefore, if this management information is read, the storage area of the image data may be specified or information related to the image data may be leaked. In this way, even with the “random number method”, the danger of browsing information cannot be completely denied.

  Thus, in the present embodiment, in the overwrite erasure process that is performed last among the multiple overwrite erasure processes, the image data that is different from the image data and that is not particularly confidential is overwritten. . In this case, any of the above-described “zero method” and “random number method” may be applied to the overwrite erasure process other than the overwrite erasure process performed at the end. Here, the “random number method” is used. Hereinafter, such an image having no confidentiality is referred to as a pseudo image, and a method using the pseudo image is referred to as a “pseudo image method”. This “pseudo image” is not an image held by the user, but is an image such as a landscape, a pattern, or a graphic prepared in advance by the manufacturer of the image processing apparatus 1, and various pseudo image data at the manufacturing stage. Are stored in a predetermined area of the storage unit 16.

  Furthermore, when the initialization process for the entire storage area as well as the erase area is executed, the pseudo image data overwrites the pseudo image data in the storage area. In this case, the data structure of the storage area after the initialization process by the “pseudo-image method” is executed is as shown in FIG. That is, since the pseudo image data is written in both the erased area 16a and the unused area 16d, there is no storage area in which “0” is written. Therefore, even if the storage area is analyzed by a malicious third party, the image data is stored in any storage area, so the contents of the image represented by each image data are browsed, If the contents are not referred to, it cannot be determined whether or not the contents are meaningful (that is, whether the image data is owned by the user or the meaningless pseudo image prepared by the device manufacturer).

(3) Security level and priority When erasing certain image data, the image processing apparatus 1 executes the overwrite erasure process as described above three times. However, as the number of erasure processes executed by the image processing apparatus 1 increases, the opportunity to accept another process during the erasure process increases. For example, when the processing received by the image processing apparatus 1 during the erasing process is extremely important, if the erasing process being executed is prioritized, the user may experience inconvenience or seriously affect the operation of the apparatus. Trouble can occur. In order to prevent such a situation, the image processing apparatus 1 assigns “priority” to the process according to the importance of each process, and executes the processes in order according to the priority. For example, even when a certain process is being executed, the image processing apparatus 1 stops the former process and executes the latter process when a process with a higher priority is accepted. That is, the image processing apparatus 1 always executes a process with the highest priority.

  For this reason, the priority of each process which the control part 11 performs is memorize | stored in the table format. Here, FIG. 3 is a diagram illustrating a description example of the management table stored in the storage unit 16. In the figure, regarding the priority, it is assumed that the smaller the numerical value is, the more preferential processing is performed, and the expression “priority is high” is used hereinafter. In FIG. 3, the priority of the OS (Operating System) related process (represented as “OS process”) is “10”. The OS-related processing often includes the central processing of the device, such as when managing the time counted by the device and periodically checking the processing waiting for execution, so the priority is the highest. It is set high.

  Next, the priority of the process related to communication (represented as “communication process”) is “30”. The processing related to communication is, for example, data exchange with a device connected by communication means via the communication unit 13. For example, if the control unit 11 receives a communication request from an external device and does not immediately execute the response, the external device may be erroneously determined that the image processing device 1 is in a failure or inoperable state. The priority is lower than the “OS processing”, but a relatively high priority is set.

  Next, the priority of processing relating to image formation (referred to as “image formation processing”) is “50”. The image forming process is inconvenient to the user even when the process is delayed more than originally, but since a serious problem is rarely caused in the operation of the apparatus, the priority is set to be relatively low.

  The priority of the process related to the user interface (UI) (represented as “UI process”) is “70”. The UI-related processing is processing for displaying various information on the display unit 17 and supplying an instruction by the operation of the operation unit 12 of the user to the control unit 11, for example. For example, during the process such as the image forming process, it is difficult to cause a big problem even if various information cannot be displayed or a user operation is not accepted. Therefore, the priority is set lower than that in the image forming process.

  In contrast to the “OS processing”, “communication processing”, “image forming processing”, and “UI processing” as described above, a security level (sensitivity) is set for the data erasing processing, and this security level unit. The priority is set in. FIG. 4 is a diagram showing priorities according to security levels. The security level is classified into a plurality of stages such as “highest confidentiality”, “high confidentiality”, “intermediate confidentiality”, and “low confidentiality”. The former has a higher security level, and the higher the security level, the higher the priority of each erasure process. Further, the priority is set lower as the number of erasure processes increases. For example, when the second erasing process for image data assigned with the security level “highest confidentiality” and the first erasing process for image data assigned with the security level “high confidentiality” compete, Since the priority is “45” while the latter is “44”, the latter processing (first erasing processing for image data assigned with the security level “high confidentiality”) is first performed. The former process (the second erasure process for the image data to which the security level “highest confidentiality” is assigned) is executed later.

(4) Operation Example Next, an operation example of the present embodiment will be described with reference to the drawings.
In the following description, a series of processes executed by the image processing apparatus in response to an accepted request is referred to as a “processing group”. For example, when the image forming process is executed, the erasing process is executed three times thereafter. The image forming process and the erasing process of a plurality of times are collectively referred to as a processing group. For “OS processing”, “communication processing”, and “UI operation”, the received “processing” is the “processing group” itself. The “erase process” is a generic term for three erase processes. Each erase process is expressed as “first erase process”, or “different erase process” is distinguished to distinguish different image forming processes. They are referred to as “image forming process a” and “image forming process b”, and the second erasing process corresponding to them is expressed as “erasing process a2” or “erasing process b2”.

  FIG. 5 is a flowchart illustrating a procedure of processing executed by the control unit 11 of the image processing apparatus 1. In the following description, a process that is started when a request is first received is referred to as a “first process”, and a series of process groups including the first process is referred to as a “first process group”. For example, when a request for an image forming process is received, the first process is an image forming process, and the first processing group includes three erasing processes for image data in addition to the image forming process. A process received subsequent to the “first process” is referred to as a “second process”, and a series of process groups including the second process is referred to as a “second process group”.

  Further, in FIGS. 6 to 8, when the control unit 11 executes the “first process” and then receives the “second process”, the processes are executed in any order in time series. It represents. In each figure, (a) represents the order of processing in the present embodiment, and (b) represents the order of processing when the configuration of the present embodiment is not provided. 6 to 8, the contents of the tables shown in FIGS. 3 and 4 are used as the security level and priority of the image data.

(4-1) Operation example 1
First, in the first operation example, the operation when the second process for the “intermediate confidential” image data is received after the start of the first process for the “highly confidential” image data is described. That is, this is a case where a second process having a lower priority is instructed while the first process group is being executed.

  In this case, when receiving the first process in FIG. 5 (step S1), the control unit 11 first executes the image forming process a (priority “50”) included in the first process group (step S2). . Next, the control unit 11 determines whether or not the second process is accepted while executing the image forming process a (step S3). The control unit 11 continues this process until all the processes included in the first process group are completed (step S4; NO) until the second process is accepted (step S3; NO). In other words, until the second process is received, the control unit 11 performs the image forming process a, the erasing process a1 (priority “44”), the erasing process a2 (priority “54”), and the erasing process a3 (priority “ 64 ″) is executed according to the priority. That is, the control unit 11 sequentially executes a plurality of data erasing processes on the image data according to the priority.

  Here, it is assumed that the second process is received while the controller 11 executes the erasing process a1 after the image forming process a is executed (step S3; YES). In this case, the control unit 11 determines the priority of the erasing process a1 and the highest priority process of the second processing group, that is, the image forming process, in order to determine whether to execute the erasing process a1 or the second process. The priority with b is compared (step S5). Here, the priority of the erasing process a1 being executed (priority “44”) is higher than the priority of the image forming process b (priority “50”) (step S6; YES). 11 continues the process being executed (erase process a1) (step S7).

  Thereafter, the control unit 11 executes processing according to the priority (step S10). Specifically, the processing is executed according to the priority assigned to each of the erasing processing a2, a3, the image forming processing b, and the erasing processing b1, b2, b3. And when another process is received in the middle of these processes (step S11; YES), the control part 11 returns to step S5, and repeats the said process steps S5-S11.

  Here, it is assumed that the control unit 11 ends the erasing process a1 without accepting another process. In this case, the control unit 11 executes the image forming process b (priority “50”) having a high priority following the erasing process a1. Thereafter, the control unit 11 repeats the processing steps S10 to S12 until the first and second processing groups are completed. That is, the control unit 11 has a priority with respect to the data erasure process being executed in the first process group, a priority with respect to a data erasure process that has not yet been executed in the first process group, and a second process group. The priority assigned to each of the plurality of data erasure processes is compared, the order of the data erasure process is determined according to the priority for each data erasure process, and the data erasure process is executed according to the determined order. Specifically, when the image forming process b1 is completed, the control unit 11 executes the next highest priority erasing process b1 (priority “53”). Then, when the erasing process b1 is completed, the control unit 11 executes the erasing process a2 (priority “54”) having a high priority, followed by the erasing process b2 (priority “63”) and the erasing process a3. (Priority “64”) and erasing process b3 (priority “73”).

  Then, when the erasing process b3 is finished, the control unit 11 determines that all the processing groups of the accepted first and second processes are finished. That is, as shown in FIG. 6A, the order in which each process is performed is as follows: image forming process a, erasing process a1, image forming process b, erasing process b1, erasing process a2, erasing process b2, erasing process a3, The erasing process b3 is performed, and the processes can be executed in order of importance.

If it is determined in step S4 in FIG. 5 that the control unit 11 has finished the first processing group (step S4; YES), all accepted processes are finished.
In step S6, when the control unit 11 determines that the process being executed has a lower priority (step S6; NO), the control unit 11 temporarily stops the process being executed (step S8) and gives priority. The process with the higher degree is executed (step S9). At this time, when the process is stopped in step S8, the address of the storage area in which the process is being executed is referred to as a “stop address”.
Moreover, if the control part 11 judges that another process is not received in step S11 (step S11; NO), it will judge whether all the process groups of the received process were complete | finished (step S12). . In this case, if the control unit 11 determines that all the processing groups including the received processing have been completed (step S12; YES), it means that all processing has been completed. On the other hand, if the control part 11 judges that the process group of the received process is not complete | finished (step S12; NO), it will return to step S10 and will repeat process step S10-S12.

  On the other hand, when only the security level of the process is considered, as shown in FIG. 6B, first, the image forming process a is executed, and the second erasing process a1 is executed during the second erasing process a1. Even if the above process is accepted, the second process that is “intermediate secret” is not executed until all of the first process group that is “high secret” is completed. Therefore, the control unit 11 executes an erasing process a2 and an erasing process a3 following the erasing process a1. Then, after all the first processing group is completed, the image forming process b, the erasing process b1, the erasing process b2, and the erasing process b3 of the second processing group are executed. That is, the order in which each process is performed is image forming process a, erasing process a1, erasing process a2, erasing process a3, image forming process b, erasing process b1, erasing process b2, and erasing process b3.

(4-2) Operation example 2
Next, an operation example 2 will be described. This operation example 2 is an operation when the second process for the “highly confidential” image data is received after the start of the first process for the “intermediate confidential” image data. That is, the second process with higher priority is instructed while the first process group is being executed.

  First, the operation of the present embodiment shown in FIG. Also in the second operation example, until the process in which the control unit 11 accepts the second process, the process steps are the same as those in the first operation example, and the description thereof is omitted. If the control unit 11 determines that the second process has been received while the erasing process a1 is being executed (step S3; YES), which of the erasing process a1 being executed and the second process is being executed? Is compared with the priority of the erasing process a1 and the priority of the second process group, that is, the image forming process b (step S5). Then, the control unit 11 determines whether or not the priority of the erasing process a1 being executed (priority “53”) is higher than the priority of the image forming process b (priority “50”). (Step S6). Then, since the control unit 11 determines that the image forming process b as the second process has a higher priority (step S6; NO), the erasing process a1 being executed is temporarily stopped (step S8). . And the control part 11 performs the image formation process b (step S9).

  And since the control part 11 will perform the process with the highest priority, determining whether another process was received, it will repeat process step S5-S12. In other words, focusing on the process executed by the control unit 11, when the image forming process b is completed, the erasing process b1 (priority “44”) having the next highest priority is executed. Then, since the control unit 11 determines that the next highest priority processing is the erasing processing a1 that is temporarily stopped in step S8, the remaining processing of the erasing processing a1 is executed. When the erasing process a1 is completed, the control unit 11 continues with the erasing process b2 (priority “54”), the erasing process a2 (priority “63”), and the erasing process b3 (priority “64”). ) And erasure processing a3 (priority “73”).

  Then, when the erasing process b3 is finished, the control unit 11 determines that all the processing groups of the accepted first and second processes are finished. That is, the order in which each process is performed is as follows: image forming process a, erasing process a1 (up to the stop address), image forming process b, erasing process b1, erasing process a1 (up to the end address), erasing process a2, erasing process b2, The erasing process a3 and the erasing process b3 are performed.

  On the other hand, as shown in FIG. 7B, when only the security level of the process is considered, when the first process is accepted for image data with a high security level, the image forming process a and the erasing process a1 are executed. If the second process is accepted during that time, the image data of the second process has a higher security level, so the second process is preferentially executed. Therefore, the erasing process a1 is temporarily stopped and the erasing process b1 is executed. Then, the erasing process b2 and the erasing process b3 are executed. When all the second processing groups are completed, the erasing process a1, the erasing process a2, and the erasing process a3, which are the remaining processes of the first process group, are executed. That is, the order of each process is as follows: image forming process a, erasing process a1 (up to the stop address), image forming process b, erasing process b1, erasing process b2, erasing process b3, erasing process a1 (up to the end address), erasing process The condition is a2 and erasing process a3.

(4-3) Operation example 3
Next, an operation example 3 will be described. In this operation example 3, the operation when the second process for the “intermediate confidential” image data is received after the start of the first process for the “intermediate confidential” image data will be described. That is, the second process with the same priority is instructed while the first process group is being executed. Furthermore, in the third operation example, an example in which processing other than the image forming processing described so far is received will be described.

  First, the operation of this embodiment shown in FIG. 8A will be described. Also in the third operation example, the control unit 11 compares the priorities of the first processing group and the second processing group, and executes the process with the higher priority. The explanation is omitted because it is equal to 2. However, in this operation example 3, since the security levels of the respective image data are equal, there is a case where the priorities of the compared processes match. For example, if attention is paid to the time t1 when the erasing process b1 in the figure ends, the control unit 11 performs two processes with the next highest priority, the erasing process a2 and the erasing process b2 (both priority is “54”). Judge that there is. In such a case, the control unit 11 may execute either process. For example, the first process executed first is prioritized and the erase process b2 is executed after the erase process a2 is performed. Like that. In addition, since the priority is the same in the erasing process a3 and the erasing process b3 at time t2, either one is given priority according to the setting. Of course, the order may be reversed, and may be set in advance at the manufacturing stage or set by the user.

In the third operation example, a case will be described in which the control unit 11 receives a communication process with an apparatus connected by a communication unit during the execution of the erasing process a3.
If it is determined that the communication process has been accepted (step S11), the control unit 11 returns to step S5, and compares the priority of the erase process a3 being executed, the erase process b3, and the communication process. Then, the control unit 11 determines that the priority (priority “64”) of the erasing process a3 being executed is the erasing process b3 (priority “64”), which is the highest priority process of the other processing group, and the communication process (priority). It is determined whether the priority is higher than (degree “30”) (step S6). Then, since the control unit 11 determines that the communication process has a higher priority (step S6; NO), the erasing process a3 being executed is temporarily stopped (step S8), and the communication process is executed (step S8). Step S9). Then, when the communication process is finished, the control unit 11 resumes the erase process a3 that has been stopped, and then executes the erase process b3. Even when the control unit 11 receives more processes, the control unit 11 does not change the process having the highest priority.

  Then, when the erasing process b3 is completed, the control unit 11 determines that all the received processing groups of the first, second, and third processes are completed. That is, the order in which the processes are performed is as follows: image forming process a, erasing process a1, image forming process b, erasing process b1, erasing process a2, erasing process b2, erasing process a3 (up to the stop address), communication process, erasing process A3 (up to the end address), erase process b3, and so on.

On the other hand, as shown in FIG. 8B, when only the security level of the process is considered, even if the second process is received during execution of the first process for image data with a high security level, Since the levels match, the second process is not executed with priority. Therefore, the operation order is the same as that of the operation example 1. When the communication process is accepted during the execution of the erasing process b2, for example, if it is determined that the communication process is given priority, the erasing process b2 is temporarily stopped and executed. When the communication process ends, the erasure process b2 is restarted and the second process group is executed to the end. That is, the order in which each process is performed is as follows: image forming process a, erasing process a1, erasing process a2, erasing process a3, image forming process b, erasing process b1, erasing process b2 (up to the stop address), communication process, erasing process b2 (up to the end address), erase process b3, and so on. As described above, even when processing other than image formation processing and data erasing processing, that is, OS processing, communication processing, and UI processing (hereinafter referred to as normal processing) is requested, the control unit 11 performs the same as described above. Process according to priority. That is, the control unit 11 assigns a priority to each of a plurality of data erasing processes and assigns a priority to a normal process. Then, the control unit 11 compares the priority with respect to the data erasure process being executed, the priority with respect to the data erasure process not yet executed, and the priority assigned to the normal process, and according to the respective priorities. The order of execution is determined, and processing is executed according to the determined order.
(5) Modifications Note that the present invention is not limited to the above-described embodiments, and can be implemented in various modes. Specifically, the following modifications are mentioned, for example. These modifications can be combined as appropriate.

(5-1) Modification 1
In the above-described embodiment, the priority of “image formation processing” is constant “50” regardless of the security level of image data. However, the priority of “image formation processing” varies depending on the security level. May be. 9 and 10 are diagrams illustrating a description example of the management table stored in the storage unit 16. First, FIG. 9 shows the priority of each process executed by the control unit 11. Each process is an “OS process”, a “communication process”, and a “UI process”, which are the same as those in the embodiment together with the priority, and will not be described. FIG. 10 shows the priority according to the security level of the image data for each image forming process and each erasing process. The security level classification method is the same as that of the above-described embodiment. For example, the priority of image data whose security level is “highest confidentiality” will be described. The priority of the image forming process is “39”. The priority of the erase process is “35”, the priority of the second erase process is “41”, and the priority of the third erase process is “47”. For image data with a security level of “High Confidential”, the priority of the image forming process is “44”, the priority of the first erase process is “40”, and the priority of the second erase process is “46”. ", And the priority of the third erase process is" 52 ". For “intermediate confidential” image data, the priority of the image forming process is “49”, the priority of the first erase process is “50”, and the priority of the second erase process is “51”. And the priority of the third erase process is “57”. For image data of “low confidentiality”, the priority of the image forming process is “54”, the priority of the first erasing process is “55”, the priority of the second erasing process is “56”, The priority of the third erasing process is “62”. Since the priority of the image forming process also differs depending on the security level of the image data, a series of processes included in the processing group is performed more quickly than in the embodiment as the image data has a higher security level.

(5-2) Modification 2
In the embodiment, the security level set for each image data is set by the user judging the importance of the image data, but may be set by the image processing apparatus 1. For example, the image processing apparatus 1 stores the user information and the security level in association with each other in the storage unit 16 and assigns a security level corresponding to the logged-in user when the input of the image data is received. Also good. For example, the higher the user's position in the company, the higher the security level, or the higher the security level of those who are engaged in business dealing with highly confidential information.

(5-3) Modification 3
Further, the image processing apparatus 1 associates the security level with a keyword that can be estimated that confidential information is included in the image, such as “confidential”, “personnel”, and “important”, in the storage unit 16. Remember. Then, the image processing apparatus 1 may optically read and extract a keyword included in the image represented by the image data, and set the security level of the image data based on the result. In addition, the image processing apparatus 1 may have a function of reading hidden printing, and may read user information and keywords embedded as hidden printing, information indicating a security level, and set a security level corresponding to the information. Good. The larger the amount of image data, the longer the time required for the erasure process. Therefore, the security level may be increased for image data with a smaller amount of data.

(5-4) Modification 4
In the embodiment, the pseudo image data is stored as it is in the erasure area and the unused area, but may be encrypted and stored. For image data that the user has determined to contain particularly sensitive information, the image data may be encrypted and stored. Therefore, when encrypted data is found, the risk of being determined to be particularly confidential data is higher than that of unencrypted data. Therefore, if the pseudo image data is also encrypted and stored, confidential image data is more difficult to find. As an encryption method, for example, if an encryption key reflecting time information is applied, the encryption method of each pseudo image data will be different. It will take more time than if it doesn't change.

(5-5) Modification 5
In the embodiment, the example in which the image processing apparatus 1 is realized by an apparatus having a printout function, a scan (image reading) function, a copy (copying) function, and a facsimile function has been described. It may be realized by an apparatus having at least one of the functions. Further, the image processing apparatus 1 may be incorporated in an information processing apparatus such as a computer that performs image processing.

(5-6) Modification 6
The program executed by the control unit 11 of the image processing apparatus 1 can be provided to the image processing apparatus 1 by being recorded on a recording medium such as a magnetic recording medium, an optical recording medium, or a ROM readable by a computer. It is also possible to download the image processing apparatus 1 by communication means such as the Internet.

1 is a block diagram illustrating a hardware configuration of an image processing apparatus according to an embodiment. It is a figure explaining the data structure of a storage area. It is the figure which showed an example of the management table which showed the priority of the process which a control part performs. It is the figure which showed an example of the management table which shows the relationship between a security level and a priority. It is a flowchart which shows the procedure of the process which a control part performs. It is a figure explaining the process of the process in the operation example 1. FIG. It is a figure explaining the process of the process in the operation example 2. FIG. It is a figure explaining the process of the process in the operation example 3. FIG. It is the figure which showed an example of the management table which showed the priority of the process which a control part performs in a modification. It is the figure which showed an example of the management table which shows the relationship between a security level and a priority in a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image processing apparatus, 11 ... Control part (assignment means, 1st erasing means, 2nd erasing means, erasing means, processing means, control means), 12 ... Operation part, 13 ... Communication part, 14 ... Image reading 15, an image forming unit, 16 a storage unit (allocation means), and 17 a display unit.

Claims (8)

When the data erasure process for erasing the image data from the storage area is repeated multiple times by writing data different from the image data to the storage area in which the image data is stored, Assigning means for assigning priority to each;
First erasing means for sequentially executing the plurality of data erasing processes for the first image data in accordance with the priority assigned to each data erasing process by the assigning means;
Second erasure means for sequentially executing the plurality of times of data erasure processing on second image data different from the first image data according to the priority assigned to each data erasure processing by the assignment means;
When a data erasing process for the second image data is requested when any of the plurality of times of the data erasing process for the first image data is being executed by the first erasing unit, Priority for data erasure processing executed by the first erasure means, priority for data erasure processing not yet executed by the first erasure means, and a plurality of data erasures for the second image data The priority assigned to each of the processes is compared, the order of execution is determined according to the priority for each data erasure process, and data is transferred to the first erasure means or the second erasure means according to the decided order. An image processing apparatus comprising: control means for controlling to execute an erasing process. When the data erasure process for erasing the image data from the storage area is repeated multiple times by writing data different from the image data to the storage area in which the image data is stored, Assigning means for assigning a priority to each and assigning a priority to a process other than a data erasing process for the image data;
An erasing unit that sequentially executes the data erasing process for the image data according to the priority assigned to each data erasing process by the allocating unit;
Execution means for executing processing other than data erasure processing on the image data in order according to the priority assigned by the assignment means;
When any one of the plurality of times of data erasure processing is being executed by the erasure means and a process other than data erasure processing is requested for the image data, the data erasure being executed by the erasure means The priority for the processing, the priority for the data erasure processing that has not yet been executed by the erasing means, and the priority assigned to each of the processes other than the data erasure processing for the image data are compared, and An image processing apparatus comprising: a control unit configured to determine an execution order according to the priority and to control the erasure unit or the processing unit to execute the process according to the determined order. A sensitivity storage means for storing a predetermined sensitivity and a priority for each of the plurality of data erasing processes in association with each other;
Comprising a sensitivity designation means for designating the sensitivity;
The image processing apparatus according to claim 1, wherein the assigning unit assigns a priority stored in the sensitivity storage unit in association with the sensitivity specified by the sensitivity specifying unit. . Keyword storage means for storing a keyword and a priority for each of the plurality of data erasing processes in association with each other,
2. The assigning unit extracts a keyword from a character image included in an image represented by the image data, and assigns a priority stored in the keyword storage unit in association with the extracted keyword. Or the image processing apparatus of 2. Pseudo image storage means for storing predetermined image data as pseudo image data;
The data erasure process executed last among the plurality of data erasure processes for image data is a process for writing the pseudo image data stored in the pseudo image storage means into the storage area. Item 3. The image processing apparatus according to Item 1 or 2. Determining means for determining whether or not the image data is encrypted;
The first and second control means are executed at the end of the plurality of data erasing processes for the image data when the determination means determines that the image data is encrypted. 6. The image processing apparatus according to claim 5, wherein the data erasing process is a process of writing and encrypting the pseudo image data or random numbers stored in the pseudo image storage unit in the storage area. On the computer,
When the data erasure process for erasing the image data from the storage area is repeated multiple times by writing data different from the image data to the storage area in which the image data is stored, An assignment function to assign a priority to each;
A first erasure function that sequentially executes the plurality of data erasure processes for the first image data according to the priority assigned to each data erasure process by the assignment function;
A second erasing function for sequentially executing the plurality of data erasing processes for the second image data different from the first image data in accordance with the priority assigned to each data erasing process by the assigning function;
When any one of the plurality of times of data erasure processing for the first image data is being executed by the first erasure function, when data erasure processing for the second image data is requested, Priorities for data erasure processing executed by the first erasure function, priorities for data erasure processing not yet executed by the first erasure function, and a plurality of data erasures for the second image data The priority assigned to each of the processes is compared, the order of execution is determined according to the priority for each data erasing process, and data is transferred to the first erasing function or the second erasing function according to the determined order. A program that realizes a control function that controls to execute the erasure process. On the computer,
When the data erasure process for erasing the image data from the storage area is repeated multiple times by writing data different from the image data to the storage area in which the image data is stored, An assigning function for assigning priorities to each and assigning priorities to processes other than the data erasure process for the image data;
An erasing function that sequentially executes the data erasing process for the image data according to the priority assigned to each data erasing process by the assignment function;
An execution function for executing processing other than data erasure processing on the image data in order according to the priority assigned by the assignment function;
When any one of the plurality of data erasing processes is executed by the erasing function and a process other than the data erasing process is requested for the image data, the data erasing being executed by the erasing function is performed. The priority for the processing, the priority for the data erasing processing that has not been executed by the erasing function, and the priority assigned to each of the processing other than the data erasing processing for the image data are compared. A program that realizes a control function that determines the order of execution according to priority and controls the erasure function or the processing function to execute processing according to the determined order.

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