Patent Publication Number: US-11650517-B2

Title: Image forming apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     The present application is a continuation of U.S. application Ser. No. 17/098,803, filed Nov. 16, 2020, which claims priority from Japanese Patent Application No. 2019-208361 filed on Nov. 19, 2019, the disclosures of which are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to an image forming apparatus in which a drum cartridge and a toner cartridge are installable. 
     BACKGROUND ART 
     An image forming apparatus in which a user-replaceable toner cartridge includes a memory is known in the art. In this image forming apparatus, when a new toner cartridge is installed, a printer ID of the image forming apparatus is written in a memory of the toner cartridge, and the toner cartridge is allowed to be used if the printer ID of the image forming apparatus and the printer ID stored in the memory of the toner cartridge are identical. 
     SUMMARY 
     However, an image forming apparatus in which two types of cartridges, i.e., a drum cartridge and a toner cartridge, are installable had not been taken into consideration. 
     In one aspect, an image forming apparatus is disclosed herein which comprises an apparatus main unit, a main unit memory, a drum cartridge installed in the apparatus main unit, a toner cartridge installed in the apparatus main unit, and a controller. The main unit memory stores printer identification information which identifies the image forming apparatus. The drum cartridge comprises a photoconductor drum, and a drum memory that stores drum identification information which identifies the drum cartridge. The toner cartridge comprises a case containing toner inside, and a toner memory that stores toner identification information which identifies the toner cartridge. 
     The controller is configured to determine whether the drum cartridge installed in the apparatus main unit is new, store in the main unit memory the drum identification information stored in the drum memory and store in the drum memory the printer identification information stored in the main unit memory, if the controller determines that the drum cartridge installed in the apparatus main unit is new. The controller is further configured to determine whether the toner cartridge installed in the apparatus main unit is new, and store in the main unit memory the toner identification information stored in the toner memory and store in the toner memory the drum identification information stored in the drum memory, if the controller determines that the toner cartridge installed in the apparatus main unit is new. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, their advantages and further features will become more apparent in detail illustrative, non-limiting description with reference to the accompanying drawings, in which: 
         FIG.  1    is a sectional view of an image forming apparatus; 
         FIG.  2    is a diagram showing an electrical connection between a controller, a main unit memory, a drum memory and a toner memory; 
         FIG.  3 A  is a diagram showing identification information stored in the main unit memory, identification information stored in the drum memory of a new drum cartridge, and identification information stored in the toner memory of a new toner cartridge before the cartridges are installed; 
         FIG.  3 B  is a diagram showing identification information stored in the main unit memory, identification information stored in the drum memory, and identification information stored in the toner memory after the cartridges are installed; 
         FIG.  4    is a flow chart showing an example process of the controller for authentication of the drum cartridge and the toner cartridge. 
         FIG.  5    is a flow chart showing a process for authentication of the drum cartridge. 
         FIG.  6    is a flow chart showing a process for authentication of the toner cartridge. 
         FIG.  7 A  is a diagram showing an apparatus main unit before installing a new drum cartridge and a new toner cartridge; 
         FIG.  7 B  is a diagram showing the apparatus main unit after installing a new drum cartridge and a new toner cartridge; 
         FIG.  8 A  is a diagram showing the apparatus main unit before installing a new toner cartridge; 
         FIG.  8 B  is a diagram showing the apparatus main unit after installing a new toner cartridge; 
         FIG.  9 A  is a diagram showing the apparatus main unit before installing a new drum cartridge; 
         FIG.  9 B  is a diagram showing the apparatus main unit after installing a new drum cartridge; 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A detailed description will be given of a non-limiting embodiment with reference made to the drawings where appropriate. 
     As shown in  FIG.  1   , an image forming apparatus  1  is a monochrome laser printer. The image forming apparatus  1  includes an apparatus main unit  2 , a feeder unit  3 , an image forming unit  4 , a controller  100  and a display  26 . 
     The apparatus main unit  2  is configured as a hollow case. The apparatus main unit  2  includes a pair of left and right side walls  21 , and a front wall  22  connecting the side walls  21 . The front wall  22  has a main unit opening  22 A. A front cover  23  is provided on the front wall  22  for opening and closing the main unit opening  22 A. 
     The feeder unit  3  comprises a feeding tray  31 , and a conveyor mechanism  32 . The feeding tray  31  is removably installed in the lower part of the apparatus main unit  2 . The conveyor mechanism  32  is configured to convey sheets S on the feeding tray  31  toward the image forming unit  4 . 
     The image forming unit  4  includes a scanner unit  5 , a belt unit  6 , a fixing device  7 , a drum cartridge  8 , and a toner cartridge  9 . 
     The scanner unit  5  is arranged in the upper part of the apparatus main unit  2  and includes a laser emitting unit, a polygon mirror, lenses, reflectors, etc., which are not shown. This scanner unit  5  is configured to emit a laser beam that rapidly scans the surface of a photoconductor drum  81  which will be described later. 
     The belt unit  6  includes a belt  61 , a drive roller  62 , and a follower roller  63 . The belt unit  6  is installable in and removable from the apparatus main unit  2 . 
     As shown in  FIG.  2   , the controller  100  includes, for example, a CPU  101 , a RAM  102 , a ROM  103 , an EEPROM  104 , and an input/output circuit, and controls printing by performing an arithmetic-logic process based on information on the installed cartridges and programs and/or data stored in the RAM  102 , the ROM  103 , etc. The RAM  102  and the EEPROM  104  are an example of a main unit memory  110 . Further, the RAM  102  is an example of a volatile memory. The CPU  101  is electrically connected to the RAM  102 , the ROM  103 , the EEPROM  104 , and a drum memory  85  and a toner memory  95  described later. The EEPROM  104  is an example of a nonvolatile memory. 
     Returning to  FIG.  1   , the display  26  is arranged on the outer surface of the apparatus main unit  2 . The display  26  displays various messages based on commands from the controller  100 . 
     The drum cartridge  8  is disposed between the feeder unit  3  and the scanner unit  5 . The drum cartridge  8  is installable in and removable from the apparatus main unit  2 . Specifically, the drum cartridge  8  is installable in and removable from the apparatus main unit  2  through the main unit opening  22 A which can be opened and closed by the front cover  23  of the apparatus main unit  2 . 
     The toner cartridge  9  is installable in the apparatus main unit  2 . The toner cartridge  9  herein is configured to be attachable to and detachable from the drum cartridge  8 . To install the toner cartridge  9 , the toner cartridge  9  is attached to the drum cartridge  8  and the drum cartridge  8  with the toner cartridge  9  is installed in the apparatus main unit  2 . 
     The drum cartridge  8  includes a frame  80 , a photoconductor drum  81 , a transfer roller  82 , a charger  83 , and the drum memory  85 . The frame  80  is configured to allow the toner cartridge  9  to be mounted thereon. The photoconductor drum  81  and the transfer roller  82  are rotatably supported at the frame  80 . 
     The drum memory  85  is, for example, a medium such as an IC chip for storing information, but is not limited to an IC chip. 
     The toner cartridge  9  includes a case  90 , a development roller  91 , a supply roller  92 , a blade  93 , and the toner memory  95 . The case  90  can contain toner inside. The development roller  91  supplies toner to the photoconductor drum  81 . The supply roller  92  supplies toner in the case  90  to the development roller  91 . The blade  93  limits thickness of the layer of toner supplied to the development roller  91 . 
     The toner memory  95  is, for example, a medium such as an IC chip for storing information, but is not limited to an IC chip. The toner memory  95  is an example of a nonvolatile memory. 
     In the drum cartridge  8 , the surface of the rotating photoconductor drum  81  is uniformly charged by the charger  83 , and then exposed to the laser beam emitted from the scanner unit  5  and rapidly scanning the surface of the photoconductor drum  81 . This causes the potential of the exposed portions to drop and forms an electrostatic latent image based on image data on the surface of the photoconductor drum  81 . 
     Subsequently, toner in the toner cartridge  9  is supplied to the electrostatic latent image on the photoconductor drum  81  by the rotating development roller  91 , and a toner image is formed on the surface of the photoconductor drum  81 . When a sheet S is conveyed between the photoconductor drum  81  and the transfer roller  82 , the toner image carried on the surface of the photoconductor drum  81  is transferred on to the sheet S. 
     The fixing device  7  includes a heating roller  71  and a pressure roller  72 . The pressure roller  72  is positioned to face the heating roller  71 . The pressure roller  72  presses the heating roller  71 . The fixing device  7  thermally fixes the toner transferred to the sheet S while the sheet S passes between the heating roller  71  and the pressure roller  72 . 
     The sheet S with a toner image thermally fixed thereon by the fixing device  7  is conveyed to sheet ejection rollers  24  positioned downstream of the fixing device  7 , and sent through the sheet ejection rollers  24  out on to a sheet output tray  25 . 
     As shown in  FIG.  3 A , the main unit memory  110  stores printer identification information which identifies the image forming apparatus  1 . The printer identification information is unique identification information predetermined for each individual printer. The unique identification information is shown in the figures by dot hatch patterns. The main unit memory  110  also stores identification information of a drum cartridge  8  and identification information of a toner cartridge  9 , unless the image forming apparatus  1  is used for the first time. 
     The drum memory  85  stores drum identification information which identifies the drum cartridge  8 . The drum identification information is unique identification information predetermined for each individual drum cartridge  8 . When the drum cartridge  8  is new, only drum identification information is stored in the drum memory  85 , and no information is stored in a specific storage area for storing printer identification information. 
     The toner memory  95  stores toner identification information which identifies the toner cartridge  9 . The toner identification information is unique identification information predetermined for each individual toner cartridge  9 . When the toner cartridge  9  is new, only toner identification information is stored in the toner memory  95 , and no information is stored in a specific storage area for storing drum identification information. 
     If the controller  100  determines that power has been turned on or the front cover  23  has been closed, the controller  100  executes drum cartridge authentication and toner cartridge authentication based on the assumption that at least one of the drum cartridge  8  and the toner cartridge  9  has been changed. The controller  100  is herein configured to allow execution of image forming only if drum cartridge authentication and toner cartridge authentication are successful. 
     Drum cartridge authentication executed by the controller  100  will be explained. 
     When the controller  100  executes drum cartridge authentication, the controller  100  first determines if a drum cartridge  8  is installed in the apparatus main unit  2 . To be more specific, the controller  100  tries to communicate with a drum memory  85 , and when communication is established between the controller  100  and a drum memory  85 , then determines that a drum cartridge  8  is installed in the apparatus main unit  2 . Alternatively, the controller  100  may be configured to use contact sensors or non-contact sensors such as optical sensors to determine whether a drum cartridge  8  is installed. 
     Next, the controller  100  determines whether the drum cartridge  8  installed in the apparatus main unit  2  is new. 
     Specifically, the controller  100  first determines whether information is stored in the specific storage area of the drum memory  85 . When the controller  100  determines that information is not stored in the specific storage area of the drum memory  85 , the controller  100  determines that the drum cartridge  8  installed in the apparatus main unit  2  is new. On the other hand, when the controller  100  determines that information is stored in the specific storage area of the drum memory  85 , the controller  100  determines that the drum cartridge  8  installed in the apparatus main unit  2  is not new. More specifically, the controller  100  is herein configured to determine that the drum cartridge  8  installed in the apparatus main unit  2  is not new when printer identification information is stored in the drum memory  85 . 
     When the controller  100  determines that the drum cartridge  8  installed in the apparatus main unit  2  is new, the controller  100  copies and stores in the main unit memory  110  the drum identification information stored in the drum memory  85 , and copies and stores in the drum memory  85  the printer identification information stored in the main unit memory  110 , as shown in  FIG.  3 B . In addition, when the controller  100  determines that the drum cartridge  8  is new, the controller  100  determines that authentication of the drum cartridge  8  succeeds. 
     It is to be understood that when previous drum identification information is stored in the main unit memory  110 , it is overwritten by the drum identification information of the drum cartridge  8  determined to be new. 
     When the controller  100  determines that the drum cartridge  8  installed in the apparatus main unit  2  is not new, the controller determines whether the printer identification information stored in the main unit memory  110  and the printer identification information stored in the drum memory  85  are identical. 
     When the controller  100  determines that the printer identification information stored in the main unit memory  110  and the printer identification information stored in the drum memory  85  are identical, the controller  100  determines that authentication of the drum cartridge  8  succeeds. 
     On the other hand, when the controller  100  determines that the printer identification information stored in the main unit memory  110  and the printer identification information stored in the drum memory  85  are not identical, the controller  100  causes a drum cartridge error to be displayed on the display  26 . 
     Toner cartridge authentication executed by the controller  100  will be explained. 
     When the controller  100  executes toner cartridge authentication, the controller  100  first determines whether a toner cartridge  9  is installed in the apparatus main unit  2 . The controller  100  is herein configured to try to communicate with a toner memory  95 , and when communication is established between the controller  100  and a toner memory  95 , then determines that a toner cartridge  9  is installed in the apparatus main unit  2 . Alternatively, the controller  100  may be configured to use contact sensors or non-contact sensors such as optical sensors to determine whether a toner cartridge  9  is installed. 
     Next, the controller  100  determines whether the toner cartridge  9  installed in the apparatus main unit  2  is new. 
     Specifically, the controller  100  first determines whether information is stored in a specific storage area of the toner memory  95 . When the controller  100  determines that information is not stored in the specific storage area of the toner memory  95 , the controller  100  determines that the toner cartridge  9  installed in the apparatus main unit  2  is new. On the other hand, when the controller  100  determines that information is stored in the specific storage area of the toner memory  95 , the controller  100  determines that the toner cartridge  9  installed in the apparatus main unit  2  is not new. More specifically, the controller  100  is herein configured to determine that the toner cartridge  9  installed in the apparatus main unit  2  is not new when drum identification information is stored in the toner memory  95 , as shown in  FIG.  3 B . 
     When the controller  100  determines that the toner cartridge  9  installed in the apparatus main unit  2  is new, the controller  100  copies and stores in the main unit memory  110  the toner identification information stored in the toner memory  95 , and copies and stores in the toner memory  95  the drum identification information stored in the drum memory  85 , as shown in  FIG.  3 B . In addition, when the controller  100  determines that the toner cartridge  9  is new, the controller  100  determines that authentication succeeds. 
     It is to be understood that when previous toner identification information is stored in the main unit memory  110 , it is overwritten by the toner identification information of the toner cartridge  9  determined to be new. 
     On the other hand, when the controller  100  determines that the toner cartridge  9  installed in the apparatus main unit  2  is not new, the controller executes the process of determining whether the drum identification information stored in the drum memory  85  and the drum identification information stored in the toner memory  95  are identical. Further, the controller  100  determines whether the toner identification information stored in the toner memory  95  and the toner identification information stored in the main unit memory  110  are identical. 
     When the controller  100  determines that the drum identification information in the toner memory  95  and the drum identification information in the drum memory  85  are identical, and that the toner identification information in the toner memory  95  and the toner identification information in the main unit memory  110  are identical, the controller  100  determines that authentication of the toner cartridge  9  succeeds. 
     On the other hand, when the controller  100  determines that the toner identification information in the toner memory  95  and the toner identification information in the main unit memory  110  are not identical, the controller  100  causes a toner cartridge error to be displayed on the display  26 . 
     When the controller  100  determines that the drum identification information in the toner memory  95  and the drum identification information in the drum memory  85  are not identical, and that the toner identification information in the toner memory  95  and the toner identification information in the main unit memory  110  are identical, the controller  100  copies and stores in the toner memory  95  the drum identification information stored in the drum memory  85 . Subsequently, the controller  100  determines that authentication of the toner cartridge has succeeded. 
     Next, an example process executed by the controller  100  will be explained with reference to  FIGS.  4  to  6   . 
     As shown in  FIG.  4   , when the controller  100  determines that the power of the image forming apparatus  1  is turned on or the front cover  23  is closed ( 51 , Yes), the controller  100  executes authentication of the drum cartridge (S 2 ) based on the assumption that the toner cartridge  9  is changed, and then executes authentication of the toner cartridge  9  (S 4 ). When the controller  100  determines that neither the power is turned on nor the front cover  23  is closed ( 51 , No), the controller  100  waits until the power of the image forming apparatus  1  is turned on or the front cover  23  is closed. 
     Next, authentication of the drum cartridge (S 2 ) will be explained with reference to  FIG.  5   . 
     As shown in  FIG.  5   , the controller  100  determines whether a drum cartridge  8  is installed in the apparatus main unit  2  (S 21 ). 
     In step  21 , when the controller  100  determines that a drum cartridge  8  is not installed in the apparatus main unit  2  (S 21 , No), the controller  100  causes a “no drum cartridge” error to be displayed on the display  26  (S 22 ) and ends the process. 
     In step  21 , when the controller  100  determines that a drum cartridge  8  is installed in the apparatus main unit  2  (S 21 , Yes), the controller  100  reads printer identification information from the drum memory  85  (S 23 ), and determines whether printer identification information is stored in the drum memory  85  (S 24 ). 
     In step S 24 , when the controller  100  determines that printer identification information is not stored in the drum memory  85  (S 24 , No), this indicates that the drum cartridge  8  is new. Therefore, the controller  100  stores in the drum memory  85  the printer identification information obtained from the main unit memory  110  (S 25 ), stores in the main unit memory  110  the drum identification information obtained from the drum memory  85  (S 26 ), determines that authentication of the drum cartridge has succeeded (S 29 ), and ends the process. 
     In step S 24 , when the controller  100  determines that printer identification information is stored in the drum memory  85  (S 24 , Yes), the controller  100  determines whether the printer identification information in the drum memory  85  and the printer identification information in the main unit memory  110  are identical (S 27 ). 
     In step  27 , if the controller  100  determines that the printer identification information in the drum memory  85  and the printer identification information in the main unit memory  110  are not identical (S 27 , No), the controller  100  causes a drum cartridge error to be displayed on the display  26  and ends the process. 
     In step S 27 , if the controller  100  determines that the printer identification information in the drum memory  85  and the printer identification information in the main unit memory  110  are identical (S 27 , Yes), the controller  100  determines that authentication of the drum cartridge succeeds (S 29 ) and ends the process. 
     Next, authentication of the drum cartridge (S 4 ) will be explained with reference to  FIG.  6   . 
     As shown in  FIG.  6   , the controller  100  determines whether a toner cartridge  9  is installed in the apparatus main unit  2  (S 41 ). 
     In step S 41 , if the controller  100  determines that a toner cartridge  9  is not installed in the apparatus main unit  2  (S 41 , No), the controller  100  causes a “no toner cartridge” error to be displayed on the display  26  (S 42 ) and ends the process. 
     In step S 41 , when the controller  100  determines that a toner cartridge  9  is installed in the apparatus main unit  2  (S 41 , Yes), the controller  100  reads drum identification information and toner identification information from the toner memory  95  (S 43 ), and determines whether drum identification information is stored in the toner memory  95  (S 44 ). 
     In step  44 , when the controller  100  determines that drum identification information is not stored in the toner memory  95  (S 44 , No), this indicates that the toner cartridge  9  is new. Therefore, the controller  100  stores in the toner memory  95  the drum identification information obtained from the drum memory  85  or the main unit memory  110  (S 45 ), stores in the main unit memory  110  the toner identification information obtained from the toner memory  95  (S 46 ), determines that authentication of the toner cartridge succeeds (S 53 ), and ends the process. 
     In step  44 , when the controller  100  determines that drum identification information is stored in the toner memory  95  (S 44 , Yes), the controller determines whether the drum identification information in the toner memory  95  and the drum identification information in the drum memory  85  are identical (S 51 ). 
     In step S 51 , when the controller  100  determines that the drum identification information in the toner memory  95  and the drum identification information in the drum memory  85  are identical (S 51 , Yes), the controller  100  determines whether the toner identification information in the toner memory  95  and the toner identification information in the main unit memory  110  are identical (S 52 ). 
     In step S 52 , when the controller  100  determines that the toner identification information in the toner memory  95  and the toner identification information in the main unit memory  110  are identical (S 52 , Yes), the controller  100  determines that authentication of the toner cartridge  9  succeeds (S 53 ) and ends the process. 
     In step S 52 , if the controller  100  determines that the toner identification information in the toner memory  95  and the toner identification information in the main unit memory  110  are not identical (S 52 , No), the controller  100  causes a toner cartridge error to be displayed on the display  26  (S 55 ) and ends the process. 
     In step S 51 , when the controller  100  determines that the drum identification information in the toner memory  95  and the drum identification information in the drum memory  85  are not identical (S 51 , No), the controller  100  determines whether the toner identification information in the toner memory  95  and the toner identification information in the main unit memory  110  are identical (S 54 ). 
     In step S 54 , when the controller  100  determines that the toner identification information in the toner memory  95  and the toner identification information in the main unit memory  110  are not identical (S 54 , No), the controller  100  causes a toner cartridge error to be displayed on the display  26  (S 55 ) and ends the process. 
     In step S 54 , when the controller  100  determines that the toner identification information in the toner memory  95  and the toner identification information in the main unit memory  110  are identical (S 54 , Yes), the controller  100  stores in the toner memory  95  the drum identification information obtained from the drum memory  85  (S 56 ), determines that authentication of the toner cartridge  9  succeeds (S 53 ), and ends the process. 
     A detail process executed by the controller  100  when a new drum cartridge  8  and a new toner cartridge  9  are installed in the apparatus main unit  2  will be explained with reference to  FIGS.  7  to  9   . 
     To begin with, referring to  FIGS.  7   a  and  7   b   , installation of a new drum cartridge  8  and a new toner cartridge  9  in an image forming apparatus used for the first time will be explained. 
     As shown in  FIG.  7 A , the main unit memory  110  of an unused image forming apparatus stores printer identification information PR 001 . The drum memory  85  of a new drum cartridge  8  stores drum identification information DR 0001 . The toner memory  95  of a new toner cartridge  9  stores toner identification information TN 0001 . 
     As shown in  FIG.  7 B , when a new drum cartridge  8  is installed in an unused image forming apparatus  1 , the controller  100  determines that the installed drum cartridge  8  is new since no information is stored in a specific storage area of the drum memory  85  for storing printer identification information. Then, the controller  100  copies and stores in the main unit memory  110  the drum identification information DR 0001  stored in the drum memory  85 , and copies and stores in the drum memory  85  the printer identification information PR 0001  stored in the main unit memory  110 . 
     When a new toner cartridge  9  is installed in an unused image forming apparatus  1 , the controller  100  determines that the installed toner cartridge  9  is new since no information is stored in a specific storage area of the toner memory  95  for storing printer identification information. Then, the controller  100  copies and stores in the main unit memory  110  the toner identification information TN 0001  stored in the toner memory  95 , and copies and stores in the toner memory  95  the drum identification information DR 0001  stored in the main unit memory  110  or the drum memory  95 . 
     Next, with reference to  FIGS.  8 A and  8 B , installation of a new toner cartridge  9  performed from the state shown in  FIG.  7 B  will be explained. 
     As shown in  FIG.  8 A , the toner memory  95  of a new toner cartridge  9  stores toner identification information TN 0002 . As shown in  FIG.  8 B , when a new toner cartridge  9  is installed in the image forming apparatus  1 , the controller  100  determines that the installed toner cartridge  9  is new since no information is stored in a specific storage area of the toner memory  95  for storing printer identification information. Then, the controller  100  copies and stores in the main unit memory  110  (overwrites the existing data TN 0001  with) the toner identification information TN 0002  stored in the toner memory  95 , and copies and stores in the toner memory  95  the drum identification information DR 0001  stored in the main unit memory  110  or the drum memory  95 . 
     Next, with reference to  FIGS.  9 A and  9 B , installation of a new drum cartridge  8  performed from the state shown in  FIG.  8 B  will be explained. 
     As shown in  FIG.  9 A , the drum memory  85  of a new drum cartridge  8  stores drum identification information DR 0002 . As shown in  FIG.  9 B , when a new drum cartridge  8  is installed in the image forming apparatus  1 , the controller  100  determines that the installed drum cartridge  8  is new since no information is stored in a specific storage area of the drum memory  85  for storing printer identification information. 
     Subsequently, the controller  100  determines whether the drum identification information stored in the drum memory  85  and the drum identification information stored in the toner memory  95  are identical, and whether the toner identification information stored in the toner memory  95  and the toner identification information stored in the main unit memory  110  are identical. Herein, the controller  100  determines that the drum identification information DR 0001  in the toner memory  95  and the drum identification information DR 0002  in the drum memory  85  are not identical. Further, the controller  100  determines that the toner identification information TN 0002  in the toner memory  95  and the toner identification information TN 0002  in the main unit memory  110  are identical 
     Accordingly, as shown in  FIG.  9 B , the controller  100  copies and stores in the toner memory  95  and the main unit memory  110  (overwrites the existing data DR 001  with) the drum identification information DR 0002  stored in the drum memory  85 . Further, the controller  100  copies and stores in the drum memory  85  the printer identification information PR 0001  stored in the main unit memory  110 . 
     The following advantages can be obtained by the image forming apparatus  1  as described above. 
     Conventionally, in an image forming apparatus in which two types of cartridges, i.e., a drum cartridge and a toner cartridge, are installable, it is not possible to recognize that a drum cartridge that had been installed in another image forming apparatus is installed in the apparatus main unit or that a toner cartridge that had been installed in another image forming apparatus is installed in the apparatus main unit. 
     However, according to the image forming apparatus  1  in which two types of cartridges, i.e., a drum cartridge and a toner cartridge, are installable, when a new drum cartridge  8  is installed in the image forming apparatus  1 , printer identification information can be stored in the drum memory  85 , and when a new toner cartridge  9  is installed in the image forming apparatus  1 , drum identification information can be stored in the toner memory  95 . Therefore, when a drum cartridge  8  that is not new is installed in the apparatus main unit  2 , the controller  100  can recognize that a drum cartridge  8  that had been installed in another image forming apparatus is installed in the apparatus main unit  2  since printer identification information is stored in the drum memory  85 . Further, when a toner cartridge  9  that is not new is installed in the apparatus main unit  2 , the controller  100  can recognize that a toner cartridge  9  that had been installed in another image forming apparatus is installed in the apparatus main unit  2  since drum identification information is stored in the toner memory  95 . 
     As a result, the image forming apparatus  1  can recognize that a cartridge had been installed in another image forming apparatus with respect to two types of cartridges, the drum cartridge  8  and the toner cartridge  9 . 
     When a toner cartridge  9  that is not new is installed in the apparatus main unit  2 , even if the drum identification information stored in the drum memory  85  and the drum identification information stored in the toner memory  95  are not identical, when the toner identification information stored in the main unit memory  110  and the toner identification information stored in the toner memory  95  are identical, the controller  100  stores in the toner memory  95  the drum identification information stored in the drum memory  85 . Therefore, the controller  100  can allow continued use of the toner cartridge  8  when the drum cartridge  8  is new, or if the drum cartridge  8  had been installed in another image forming apparatus, as long as the toner cartridge  9  had not been installed in another image forming apparatus. 
     When a toner cartridge  9  that is not new is installed in the apparatus main unit  2 , and the drum identification information stored in the main unit memory  110  and the drum identification information stored in the toner memory  95  are identical, the controller  100  may allow execution of image forming. Further, when a toner cartridge that is not new is installed in the apparatus main unit  2 , the controller  100  may prohibit execution of image forming when the drum identification information in the drum memory  85  and the drum identification information in the toner memory  95  are not identical. Therefore, when a toner cartridge  9  that had been installed in another image forming apparatus is installed in the apparatus main unit  2 , execution of image forming can be prohibited. 
     It is to be understood that the illustrative, non-limiting configuration and features of the image forming apparatus described above may be modified into various configurations as exemplified below. 
     The controller described above allows execution of image forming when authentication of the drum cartridge and authentication of the toner cartridge are successful. However, execution of image forming may be allowed even when authentication of the drum cartridge and authentication of the toner cartridge are not successful. 
     In the image forming device  1  described above, the toner cartridge  9  is attachable and detachable to the drum cartridge  8 . However, the toner cartridge and the drum cartridge may be independently attachable and detachable to the apparatus main unit. 
     Although a monochromatic laser printer is given as an example of an image forming apparatus, the image forming apparatus may be a color laser printer, a copy machine or a multifunction machine. 
     The elements described in the above disclosure and modifications may be implemented selectively and in combination.