Image forming apparatus comprising pattern adding function

An image forming apparatus includes: a storage unit including unique information identify to an apparatus main unit; a setting unit including setting information of the apparatus main unit instead of the unique information; a pattern addition unit that adds an addition pattern based on a unique pattern generated from the unique information or a setting pattern generated from the setting information to image data that is input to the apparatus main unit; an image formation unit that forms a visual image of the image data and an addition image of the addition pattern which is hardly recognized by eyes on a recording medium; and a control unit that changes the addition pattern formed by the image formation unit from the unique pattern to the setting pattern when an error depending on the unique information occurs.

FIELD

Embodiments described herein relate to an image forming apparatus that can identify an apparatus used for image formation by adding a particular pattern to an image pattern during print.

BACKGROUND

There are image forming apparatuses having a function of enabling a used image forming apparatus to be identified from a print image. The identification of the image forming apparatus is effective in the investigation of criminal acts such that the apparatus is illegally used to forge paper money or securities. In order to identify the image forming apparatus used for print, there are image forming apparatuses that make prints by adding a particular pattern that is hardly recognized by human's eyes to an image pattern. In the image forming apparatus that makes prints by adding the particular pattern to the image pattern, up to now, although a print function of the image forming apparatus is normal, if the function of adding the particular pattern is abnormal or there occurs an abnormality caused by data of the particular pattern, print operation per se by the image forming apparatus is prohibited.

However, although the print function is normal, if the use of the image forming apparatus is prohibited because only the function of investigating a few illegal persons are abnormal, there is a risk that inconvenience is forced on a large majority of honest users.

From this viewpoint, there is desired development of the image forming apparatus that provides convenience of a user so that the image forming apparatus can be used while providing the function for investigating the illegal user, if the print function is normal even though the function for identifying the image forming apparatus used for print is abnormal.

DETAILED DESCRIPTION

According to an embodiment, there is provided an apparatus including: a storage unit including unique information identify to an apparatus main unit; a setting unit including setting information of the apparatus main unit instead of the unique information; a pattern addition unit that adds an addition pattern based on a unique pattern generated from the unique information or a setting pattern generated from the setting information to image data that is input to the apparatus main unit; an image formation unit that forms a visual image of the image data and an addition image of the addition pattern which is hardly recognized by eyes on a recording medium; and a control unit that changes the addition pattern formed by the image formation unit from the unique pattern to the setting pattern when an error depending on the unique information occurs.

Hereinafter, embodiments will be described.

FIG. 1illustrates a main portion of a 4-drum tandem color printer1that is an image forming apparatus according to a first embodiment. The color printer1includes four sets of image formation stations13Y,13M,13C, and13K, which configure image formation units arranged in parallel along a lower side of a transfer belt12. The image formation stations13Y,13M,13C, and13K include photoconductive drums14Y,14M,14C, and14K, respectively. The image formation stations13Y,13M,13C, and13K form toner images of Y (yellow), M (magenta), C (cyan), and K (black) on the photoconductive drums14Y,14M,14C, and14K, respectively.

The color printer1includes a laser exposure device configuring the image formation unit. The laser exposure device20irradiates the photoconductive drums14Y,14M,14C, and14K between the chargers16Y,16M,16C, and16K and the developing devices17Y,17M,17C, and17K with laser beams corresponding to the respective colors to form electrostatic latent images on the photoconductive drums14Y,14M,14C, and14K. The developing devices17Y,17M,17C, and17K form toner images of Y (yellow), M (magenta), C (cyan), and K (black) on the photoconductive drums14Y,14M,14C, and14K, respectively.

The color printer1includes a backup roller12aand a driven roller12bbetween which the transfer belt12extends, and allows the transfer belt12to travel in a direction of an arrow f. The color printer1includes primary transfer rollers26Y,26M,26C, and26K at positions facing the photoconductive drums14Y,14M,14C, and14K through the transfer belt12, respectively. The primary transfer rollers26Y,26M,26C, and26K primarily transfer the toner images onto the photoconductive drums14Y,14M,14C and14K to the transfer belt12superimpose on top of another. The photoconductive cleaners18Y,18M,18C, and18K remove toner remaining on the photoconductive drums14Y,14M,14C, and14K, respectively, after primary transfer, and recover the removed toner.

The color printer1includes a secondary transfer roller27at a secondary transfer position facing the backup roller12athrough the transfer belt12. The color printer1secondarily transfers the toner images on the transfer belt12to a sheet P fed from a sheet feed unit28at a nip between the transfer belt12and the secondary transfer roller27in a lump. The color printer1includes a fuser unit30and a sheet discharge roller31downstream of the secondary transfer roller27along a transport direction of the sheet P. The color printer1fixes the toner image on the sheet P through the fixing device30, and discharges the sheet P through the sheet discharge roller31.

The image forming apparatus may be, for example, a revolver-type printer or an inkjet printer.

Subsequently, addition of the addition pattern to the image data will be described.FIG. 2illustrates a block diagram of a control system100that mainly includes a pattern addition function in the color printer1. A CPU110that is a control unit of the color printer1includes a program memory112and a work RAM117, which are setting units connected to the color printer1through a CPU bus111. The program memory112stores, for example, a manufacturer name and a model name-type, which are setting information incorporated therein for basic control of the color printer1in advance, as well as predetermined common data therein. Further, the program memory112stores an addition concentration value that is a concentration of the addition pattern, corresponding to the image data to be input to the color printer1. A manufacturer code may be stored as the setting information instead of the manufacturer name. The work RAM117stores the print operation of the color printer1therein.

The CPU110includes a nonvolatile memory118that is a storage unit. The nonvolatile memory118stores, for example, a manufacturer name, a model name-type, and serial number, which are unique information identify to the color printer1therein. The common data stored in the program memory112is different from serial number stored in the nonvolatile memory118. Also, the common data cannot identify the respective color printers1. The common data is used for control of the color printer1when an error depending on the unique information occurs. The common data is, for example, contents describing a fact that an error depending on the unique information of the color printer1occurs. The common data may be, for example, contents describing a production area of the color printer1.

A particular pattern generation unit120of the control system100encodes the unique information or the setting information input from the CPC110into a bit map. The particular pattern generation unit120encodes a unique pattern that is the addition pattern from the unique information, encodes the setting pattern which is the addition pattern from the setting information, and outputs the encoded patterns to a lookup table130.

The control system100includes a main scanning counter131and a sub-scanning counter132. An image clock (MCLK) for transferring an image is input to the main scanning counter131and the sub-scanning counter132. A horizontal synchronization signal (HSYNC) that synchronizes a scanning start is input to the sub-scanning counter132. The main scanning counter131inputs a column address to the lookup table130, and the sub-scanning counter132inputs a row address to the lookup table130.

The control system100includes an adder circuit140that receives the addition concentration value from the CPU110, a first selector150that selects the image data and an image part of the lookup table130, and a second selector160that selects the image data, and data from the first selector150in a color mode of yellow (Y).

The particular pattern generation unit120, the lookup table130, the main scanning counter131, the sub-scanning counter132, the adder circuit140, the first selector150, and the second selector160configure a pattern addition unit170. The control system100adds the unique pattern or the addition pattern of the setting pattern formed with toner of yellow (Y) to the input image data through the pattern addition unit170to output the resultant data to the laser exposure device20. In a print image formed on, for example, a sheet by the color printer1, the addition pattern of yellow (Y) is added to a visual image of the image pattern formed on the basis of the image data. Toner of yellow (Y) that forms the addition pattern is low in contrast with a white sheet, and hardly recognized by human's eyes. Accordingly, when the print image on the sheet is viewed by a human, almost only the image pattern is visible.

At the time of investigating injustice when the color printer1is illegally used, for example, a print image is read by an addition pattern read device with the result that the addition pattern that is hardly recognized by eyes can be read.

The color printer1having the function of adding the addition pattern to the image data determines an error of the addition pattern upon starting print operation.FIG. 3shows a flowchart of determining the error of the addition pattern. Upon starting the error determination, the CPU110detects whether the pattern addition unit170is abnormal, or not. When the particular pattern generation unit120, the lookup table130, the adder circuit140, the first selector150, and the second selector160normally function, the CPU110detects that the pattern addition unit170is not abnormal (yes in ACT200). If the pattern addition unit170is abnormal (no in ACT200), the CPU110advances to ACT220.

If the pattern addition unit170is not abnormal (yes in ACT200), the CPU110advances to ACT201, and detects whether the nonvolatile memory118that stores the unique information therein is abnormal, or not. If the nonvolatile memory118is normal (yes in ACT201), the CPU110advances to ACT202, and detects whether an access to the nonvolatile memory118is abnormal, or not. If the nonvolatile memory118is abnormal (no in ACT201), the CPU110advances to ACT210.

If the access to the nonvolatile memory118can be normally achieved (yes in ACT202), the CPU110advances to ACT203, and detects whether the unique information within the nonvolatile memory118is abnormal, or not. If the access to the nonvolatile memory118is abnormal (no in ACT202), the CPU110advances to ACT210.

If all of the manufacturer name, the model name-type, and the serial number, which are the unique information within the nonvolatile memory118are normal (yes in ACT203), the CPU110advances to ACT204. If the unique information in the nonvolatile memory118is abnormal (no in ACT203), the CPU110advances to ACT210.

In ACT204, the CPU110reads the unique information within the nonvolatile memory118, and inputs the unique information having the manufacturer name, the model name-type, and the serial number to the particular pattern generation unit120. The particular pattern generation unit120generates the unique pattern from the unique information. As a result, the CPU110makes the color painter1usable with addition of the unique pattern to the image data (ACT206), and completes the error determination of the addition pattern.

After the error determination of the addition pattern has been completed, since there is no error depending on the unique information, the color printer1adds the unique pattern to the input image data to form an image. A print image formed by the color printer1is an image in which a visual image of the image pattern based on the image data, and the unique pattern hardly recognized by eyes are superimposed on each other.

If the pattern addition unit170is abnormal (no in ACT200) when the error determination of the addition pattern is conducted, and the CPU110advances to ACT220, the CPU110displays a call for service, for example, on a display panel180of the color printer1(ACT220). Furthermore, the CPU110prohibits use of the color printer1(stops the color printer1) (ACT221), and completes the error determination of the addition pattern.

If the nonvolatile memory118is abnormal (no in ACT201), the access to the nonvolatile memory118is abnormal (no in ACT202), or the unique information within the nonvolatile memory118is abnormal (no in ACT203), due to the error depending on the unique information when the error of the addition pattern is determined, the CPU110advances to ACT210. In ACT210, the CPU110changes the addition pattern added to the image data from the unique pattern to the setting pattern. The setting pattern is a pattern that does not include information (for example, serial number) unique to each main unit of the color printers1, but is generated from information such as the manufacturer name, the model name-type, and the common data.

In ACT210, the CPU110reads the manufacturer name, the model name-type, and the common data, which are the setting information within the program memory112, and inputs the setting information to the particular pattern generation unit120. The particular pattern generation unit120generates the setting pattern from the setting information. The CPU110makes the color printer1usable with addition of the setting pattern to the image data (ACT211), and completes the error determination of the addition pattern.

Even though there are various errors depending on the unique information when the error of the addition pattern is determined, if the pattern addition unit170normally functions, the CPU110makes the color printer1usable without prohibiting the use of the color printer1.

Since there is an error depending on the unique information, after the error of the addition pattern is determined, the color printer1adds the setting pattern instead of the unique pattern to the input image data to form an image. The print image formed by the color printer1is an image in which a visual image of the image pattern based on the image data, and the setting pattern hardly recognized by eyes are superimposed on each other.

For that reason, at the time of investigating injustice when the color printer1is illegally used, if the unique pattern having the serial number is added to the image pattern as the addition pattern, an investigator can identify one color printer1used for print. On the other hand, if the setting pattern having the manufacturer name, the model name-type, and predetermined common data is added to the image pattern as the addition pattern at the time of investigating injustice, the investigator cannot identify one color printer that has been used for print. However, the investigator can identify the manufacturer name and the model name-type from the setting pattern, and can further identify a fact that no unique pattern is added due to the error.

According to the first embodiment, when the print function of the color printer1is normal during print, if the pattern addition unit170is abnormal, the CPU110prohibits the use of the color printer1. If the print function of the color printer1and the pattern addition unit170are normal, and an error depending on the unique information occurs, the CPU110does not prohibit the use of the color printer1, but changes the addition pattern added to the image data from the unique pattern to the setting pattern having the manufacturer name, the model name-type, and predetermined common data so that the color printer1is useable.

Even though an error depending on the unique information occurs, the user can use the color printer1, and obtains convenience. On the other hand, even though there is an error depending on the unique information, the CPU110adds the setting pattern as the addition pattern instead of the unique pattern to the image pattern. Accordingly, the investigator cannot identify one color printer used for print at the time of investigating injustice, but can identify the manufacturer name and the model name-type of the color printer used for print, which is helpful in investigation.

Next, a second embodiment will be described. The second embodiment is different from the above-mentioned first embodiment in the contents of the setting information. In the second embodiment, the same configurations as those described in the above-mentioned first embodiment are denoted by identical symbols, and a detailed description thereof will be omitted.

In the second embodiment, error statuses for identifying various errors depending on the unique information are provided as the setting information instead of the unique information. In the second embodiment, the CPU110saves the error statuses of the various errors occurring while the color printer1is being driven in the work RAM117. As a result, the setting information includes the manufacturer name and the model name-type stored in the program memory112, and the error statuses stored in the work RAM117.

If the pattern addition unit170is abnormal when the error determination is conducted, the CPU110stores, for example, 1 in bit3of the work RAM117as the error status. Likewise, the CPU110stores 1 in bit0if the nonvolatile memory118is abnormal, stores 1 in bit1if the access to the nonvolatile memory118is abnormal, and stores 1 in bit2if the unique information in the nonvolatile memory118is abnormal.

FIG. 4shows a flowchart for determining the error of the addition pattern. When the error determination starts, the CPU110sets all of bit3, bit0, bit1, and bit2in the work RAM117to 0, and clears the error statuses (ACT300). Then, the CPU110detects whether the pattern addition unit170is abnormal, or not. If the pattern addition unit170is not abnormal (yes in ACT301), the CPU110advances to ACT302, and detects whether the nonvolatile memory118is abnormal, or not. If the pattern addition unit170is abnormal (no in ACT301), the CPU110advances to ACT310.

If the nonvolatile memory118is normal (yes in ACT302), the CPU110advances to ACT303, and detects whether the access to the nonvolatile memory118is abnormal, or not. If the nonvolatile memory118is abnormal (no in ACT302), the CPU110advances to ACT311.

If the access to the nonvolatile memory118can be normally performed (yes in ACT303), the CPU110advances to ACT304, and detects whether the unique information in the nonvolatile memory118is abnormal, or not. If the access to the nonvolatile memory118is abnormal (no in ACT303), the CPU110advances to ACT312.

If all of the manufacturer name, the model name-type, and the serial number, which are the unique information within the nonvolatile memory118are normal (yes in ACT304), the CPU110advances to ACT306. If the unique information in the nonvolatile memory118is abnormal (no in ACT304), the CPU110advances to ACT313.

In ACT306, the CPU110reads the unique information within the nonvolatile memory118, and inputs the unique information having the manufacturer name, the model name-type, and the serial number to the particular pattern generation unit120. The particular pattern generation unit120generates the unique pattern from the unique information. As a result, the CPU110makes the color printer1usable with addition of the unique pattern to the image data (ACT307), and completes the error determination of the addition pattern.

If the pattern addition unit170is abnormal at the time of determining the error of the addition pattern (no in ACT301), and the CPU110advances to ACT310, the CPU110stores 1 in bit3of the work RAM117. Then, the CPU110displays a call for service on the display panel180of the color printer1(ACT320), prohibits the use of the color printer1(ACT321), and completes the error determination of the addition pattern.

If the nonvolatile memory118is abnormal due to the error depending on the unique information at the time of determining the error of the addition pattern (no in ACT302), the CPU110stores 1 in bit0of the work RAM117(ACT311). If the access to the nonvolatile memory118is abnormal (no in ACT303), the CPU110stores 1 in bit1of the work RAM117(ACT312). Or, if the unique information within the nonvolatile memory118is abnormal (no in ACT304), the CPU110stores 1 in bit2of the work RAM117(ACT313). Then, the CPU110advances to ACT314.

In ACT314, the CPU110changes the addition pattern added to the image data from the unique pattern to the setting pattern. The setting pattern is a pattern that does not include information (for example, serial number) unique to each main unit of the color printers1, but is generated from information such as the manufacture name, the model name-type, or the common data.

In ACT314, the CPU110reads the manufacturer name and the model name-type which is the setting information within the program memory112, and the error statuses which is the setting information within the work RAM117, and inputs the setting information to the particular pattern generation unit120. The particular pattern generation unit120generates the setting pattern from the setting information. The CPU110makes the color printer1usable with addition of the setting pattern to the image data (ACT316), and completes the error determination of the addition pattern.

Accordingly, even though there are various errors depending on the unique information at the time of determining the error of the addition pattern, the CPU110makes the color printer1usable without prohibiting the use of the color printer1if the pattern addition unit170normally functions.

If there is an error depending on the unique information, the setting pattern based on the setting information having the manufacturer name, the model name-type, and the error statuses is added, instead of the unique pattern based on the unique information, to the image pattern based on the image data printed by the color printer1. For that reason, at the time of investigating injustice when the color printer1is illegally used, the investigator cannot identify one color printer1used for print. However, the investigator can identify the manufacturer name and the model name-type from the setting pattern instead of the unique pattern, and can further identify a fact that no unique pattern is added due to the error.

According to the second embodiment, when the print function of the color printer1is normal during print, if the pattern addition unit170is abnormal, the CPU110prohibits the use of the color printer1. If the print function of the color printer1and the pattern addition unit170are normal, and the error depending on the unique information occurs, the CPU110changes the addition pattern added to the image data from the unique pattern to the setting pattern having the manufacturer name, the model name-type, and the error statuses without prohibiting the use of the color printer1, and makes the color printer1usable.

Even though the error depending on the unique information occurs, the user can use the color printer1and obtains the convenience. On the other hand, even though the error depending on the unique information occurs, the CPU110adds the setting pattern to the image pattern instead of the unique pattern as the addition pattern. Accordingly, if the color printer1is illegally used, the manufacturer name and the model name-type of the color printer1used for print can be identified at the time of investigating injustice, which is helpful in the investigation. Also, the error status is found, which is helpful in repairing an abnormal portion.

Subsequently, a third embodiment will be described. The third embodiment is different from the above-mentioned second embodiment in the contents of the setting information. In the third embodiment, the same configurations as those described in the above-mentioned second embodiment are denoted by identical symbols, and a detailed description thereof will be omitted.

In the third embodiment, the manufacturer name, the model name-type, and date and time at the time of printing, which is an image formation time, are provided as the setting information instead of the unique information.

FIG. 5shows a flowchart for determining the error of the addition pattern. The error determination is implemented substantially in the same manner as that of the error determination in the second embodiment. At the time of determining the error of the addition pattern, if the nonvolatile memory118is abnormal (no in ACT302) due to the error depending on the unique information, the CPU110stores 1 in bit0of the work RAM117(Act311). If the access to the nonvolatile memory118is abnormal (no in ACT303), the CPU110stores 1 in bit1of the work RAM117(ACT312). Or, if the unique information within the nonvolatile memory118is abnormal (no in ACT304), the CPU110stores 1 in bit2of the work RAM117(ACT313). The CPU110then advances to ACT410.

In ACT410, the CPU110changes the addition pattern added to the image data from the unique pattern to the setting pattern. The setting pattern is a pattern that does not include information (for example, serial number) unique to each main unit of the color printers1, but is generated from information such as the manufacturer name, the model name-type, or the common data.

In ACT410, the CPU110reads the manufacturer name, the model name-type and date and time at the time of printing within the program memory112, as the setting information, and inputs the setting information to the particular pattern generation unit120. The particular pattern generation unit120generates the setting pattern from the setting information. The CPU110makes the color printer1usable with addition of the setting pattern to the image data (ACT411), and completes the error determination of the addition pattern.

Accordingly, even though there are various errors depending on the unique information at the time of determining the error of the addition pattern, the CPU110makes the color printer1usable without prohibiting the use of the color printer1if the pattern addition unit170normally functions.

If there is an error depending on the unique information, the setting pattern based on the setting information having the manufacturer name, the model name-type, and date and time at the time of printing is added, instead of the unique pattern based on the unique information, to the image pattern based on the image data printed by the color printer1. For that reason, at the time of investigating injustice when the color printer1is illegally used, the investigator cannot identify one color printer1used for print. However, the investigator can identify the manufacturer name and the model name-type from the setting pattern instead of the unique pattern, and can further identify date and time at the time of printing.

According to the third embodiment, when the print function of the color printer1is normal during print, if the pattern addition unit170is abnormal, the CPU110prohibits the use of the color printer1. If the print function of the color printer1and the pattern addition unit170are normal, and the error depending on the unique information occurs, the CPU110changes the addition pattern added to the image data from the unique pattern to the setting pattern having the manufacturer name, the model name-type, and date and time at the time of printing without prohibiting the use of the color printer1, and makes the color printer1usable.

Even though the error depending on the unique information occurs, the user can use the color printer1and obtains the convenience. On the other hand, even though the error depending on the unique information occurs, the CPU110adds the setting pattern as the addition pattern to the image pattern instead of the unique pattern. Accordingly, if the color printer1is illegally used, the manufacturer name and the model name-type of the color printer1used for print as well as date and time at the time of printing can be identified at the time of investigating injustice, which is helpful in the investigation.

According to at least one of the above embodiments, even though the error depending on the unique information for identifying a certain color printer1occurs, if the print function and the pattern addition unit170are normal, the user can use the color printer1, and obtains convenience. Moreover, when the illegal use of the color printer is investigated, at least the manufacturer name, and the model name-type of the applied color printer1can be identified, which is helpful in investigation.