Abstract:
In a printing or copying device which has one or several exchangeable part units with a modular assembly, the part unit to be identified has an identification device with a non-volatile memory for storing function-relevant operating data of the part unit, said operating data being allocated to operating states. The part unit also has a communication interface for detachably connecting the identification device to a process control device of the printing or copying device.

Description:
BACKGROUND OF THE INVENTION 
     The invention is directed to a printer or copier device having modularly constructed, interchangeable sub-units and an identification arrangement allocated to the sub-units for storing function-relevant operating data allocated to operating conditions, and is also directed to a method for the operation of such a device. 
     PCT/DE95/00635 discloses an electrophotographic printer means for both-sided printing of a web-shaped, narrow recording medium and for single-sided printing of one broad recording medium or a plurality of parallel, narrow recording media. Given the known printer unit, the various units are designed as interchangeable modules. It is thus possible, for example, to adapt the printer unit to the greatest variety of operating conditions by merely replacing the electrophotographic printer module. 
     A multi-color simplex or duplex mode is possible with the printer unit by inserting a developer station with a plurality of developer chambers arranged side-by-side that is disclosed by DE-C1-195 40 138. 
     When the printer unit is employed only in single-color mode, a developer station is utilized as disclosed by PCT/DE95/00635. 
     Both publications are incorporated into the disclosure of this application. 
     High-performance printers of that type are frequently employed for printing out data in computer centers. These data can, for example, be invoices, control decisions or other individualized printouts, for example individualized advertising. When a plurality of these devices are utilized in shifts in the computer center, then the majority of print jobs are print jobs in single-color simplex or duplex mode. A smaller part of the print jobs require multi-color printing mode. With modularly constructed printers, it is therefore possible to keep one or more developer stations suitable for the multi-color printing mode ready as disclosed, for example, by DE-C1-4126465, and to insert this as needed into the corresponding printer given the presence of a multi-color printing job and to interchange it with the single-color developer station. A uniform, performance-adapted usage of the printer thus derives. 
     The various, modularly constructed units of the printer unit, however, are subject to wear. They require maintenance dependent on the duration of utilization. This is particularly true of the developer stations with the single-color or multi-color toner contained therein. Dependent on the quantity printed, the toner mix composed of carrier and toner particles changes and fresh toner must be supplied. 
     When, thus, the greatest variety of developer stations or, respectively, the greatest variety of unit modules are to be employed in the greatest variety of printer units, it is necessary that the operator be given information about the operating conditions of the interchanged module after the replacement. These operating conditions can, for example, be the toner filling condition in the case of developer stations and, thus, the information about the quantity of printing still available or, respectively, the information about the quantity of printing already printed with the developer station and, thus, the history of the developer station. Given fixing stations, it is of interest to obtain information about the wear condition and, thus, the operating duration of the fixing station, etc. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a printer or copier device having one or more modularly constructed, interchangeable sub-units such that, given simultaneous operation of a plurality of printers, an operator is in the position to replace the modules performance-adapted and to monitor their operating conditions. 
     In a printer or copier device of the tye initially cited, this object is achieved. 
     According to the invention whereby a printer or copier device has one or more modularly constructed, interchangeable sub-units. At least one of the sub-units which is to be identified has an identification unit having a non-volatile memory for storing operating data of the sub-unit allocated to function-relevant operating conditions. A communication interface is provided for coupling the identification unit to a process control unit of the device, the communication interface effecting an at least partially wireless data transmission between the sub-unit and the process control unit. 
     According to another aspect of the invention, a method and apparatus is provided for operation of a printer or copier device wherein a toner container is provided. An identification unit is provided having a non-volatile memory for storing operating data as well as a communication interface for coupling of the identification unit to a process control unit of the printer or copier device. The toner container is inserted into the printer or copier device and then a read station is checked to determine whether an electronic data memory is present on the toner container. When a data memory is present, stored data are read from the data store by the read station and are supplied to the process control unit. 
     In another aspect of the invention, a toner container is provided for employment in a printer or copier device having a process control unit. An identification unit is provided with a non-volatile memory for storing operating data as well as a communication interface for transmission of at least one of data and energy between the identification unit and the process control unit. 
     The goal is also achieved with the invention of providing the modules such that information about the operating condition of the modules can be called at any time. 
     Advantageous embodiments of the invention are described in the subclaims. 
     According to the invention, each of the sub-units is provided with an identification arrangement that contains electronic components such as a flat module and that is in the position of autonomously undertaking both identification as well as storing in a non-volatile memory. An automatic balancing of the function parameters of the overall system set in a higher-ranking unit is thus possible, incorrect operations being thereby prevented. 
     All function-relevant operating conditions of the sub-unit are thereby stored. 
     This enables an exact tracking of operating conditions and malfunctions for each sub-unit individually and unambiguously. This is a considerable advantage in case of service or in the analysis of returns. 
     When the sub-unit is a matter of a developer station, then the mechanism of this developer station is implemented such that the technically adept lay person can implement the interchange of this sub-unit himself and without monitoring by specifically trained personnel. According to the invention, a flat module equipped with a micro-controller is integrated in this developer station, this flat module being in communication via a communication interface, for example a CAN (Controller Area Network) bus, with the higher-ranking process controller (device controller) that controls this sub-unit. 
     Dependent on the operating conditions acquired by this higher-ranking controller, the assembly integrated on the sub-unit, for example the assembly integrated on the developer station, deposits the operating data in a suitable, non-volatile memory, for example, an EEPROM. As a result thereof, the data allocated to the operating conditions are not lost when the developer station is removed from the printer and thus loses power. When the developer station is re-introduced into a printer, whereby it is of no significance whether it is the same printer or a structurally identical, different printer, the corresponding settings are read out upon demand by the higher-ranking process controller, being read out from the non-volatile memory and being made available via the communication interface and, for example, being displayed on an operating display. The input of, for example, the serial number in the toner type, etc., is only required upon initial installation of a developer station equipped in this way. 
     In a further exemplary embodiment of the invention, a sub-unit contains a non-volatile memory in which both identification data as well as operating data of the sub-unit are stored. After the installation of the unit, the identification data are identified and interpreted by an identification or read arrangement. When the memory is missing or when the identification data are illegible, then a message is generated on a display means, and the operator is requested to input the data. Subsequently, standard values matching the identification data are offered for the operating parameters and the printing mode is begun. 
     The memory is usually not present particularly given older models of sub-units. The invention makes it possible to employ both these older as well as the more recent sub-units provided with memories in printer or copier devices without having to forego the advantages of the most recent developments. 
     In a further, preferred exemplary embodiment of the invention the data transmission between electronic memory and identification arrangement occurs in wireless fashion. As a result thereof, it is possible to provide an identification arrangement fixed to the device and to accomplish the data transfer between it and the memory reliably and without time delay after the insertion of the sub-unit. 
     In particular, performance-adapted operation of a plurality of printers in parallel operation is possible due to the invention. A uniform usage of all printers in a printer park thus derives with high operating dependability, since the operating conditions of all unit modules are constantly monitored. 
     A smaller component part that is provided for integration in a larger sub-unit, for example a toner bottle that is installed into a developer station, can also be understood as sub-unit in the sense of the invention. 
     Particularly given toner bottles, it is proven advantageous to equip these with a wireless communication location. Such interfaces can be obtained, for example, as chip cards that contain a data store (EEPROM), an electronic circuit for memory management and data transmission as well as an antenna that serves both for data transmission as well as for the energy supply of the chip card. Compared to a data transfer via electrical contacts, a wireless data transmission has the advantages that it is not subject to any wear and cannot be negatively influenced by contamination. Particularly given toner bottles, the dependability of the data transmission remains the same despite dust at the communication interfaces of the toner bottle and/or at the device. 
     Embodiments of the invention are shown in the drawings and are described in greater detail below by way of example. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic illustration of an electrophotographic printer means comprising interchangeable sub-units in the form of modules; 
     FIG. 2 is a schematic block circuit diagram of an identification arrangement coupled to an interchangeable developer station; 
     FIG. 3 is a schematic block circuit diagram of the coupling of the apparatus controller of the device with the identification arrangement; 
     FIG. 4 is a schematic block circuit diagram of a control panel process control arrangement allocated to the control panel; 
     FIG. 5 shows the part of the developer station in which a toner bottler is introduced; 
     and 
     FIG. 6 is low chart. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An electrophotographic printer unit single-color or multi-color, single-sided or both-sided printing of web-shaped recording media  10  having different web width fundamentally known from PCT/DE95/00635 and schematically shown in FIG. 1 contains an electromotively driven photoconductor drum  11  as intermediate carrier. The various units for the electrophotographic process are grouped around the intermediate carrier  11 . These are essentially a charging unit  12  in the form of a charging Corotron for charging the intermediate carrier  11 ; a character generator having a light-emitting diode comb for character-dependent illumination of the intermediate carrier  11  that extends over the entire useable width of the intermediate carrier  11 ; a developer station  14  for inking the character-dependent charge image on the intermediate carrier  11  with the assistance of a single-component or two-component developer mix; a transfer printing station  15  that extends over the width of the intermediate carrier  11  and with which the toner images are transferred onto the recording medium  10 . For removing the residual toner after the development and the transfer printing, a cleaning station  16  is provided with cleaning brush and corresponding extraction unit integrated therein as well as a discharge unit  17 . The intermediate carrier  11  is electromotively driven and moves in arrow direction during printing operations. 
     The printer unit also contains a fixing station  18  following the transfer printing station  15  in the conveying direction of the recording medium, said fixing station  18  being designed as thermal print fixing station, and also contains a delivery unit  21  following the fixing station with guide rollers for delivering the recording medium  10  to an internal stacking unit  22  or to an external stacking unit or other post-processing unit arranged outside the printer unit. 
     The web-shaped recording medium  10  is fabricated, for example, as pre-folded continuous form paper provided with margin perforations and is supplied to the transfer printing station  15  via delivery rollers  24  of a pivotable paper separating unit proceeding from an internal supply region  23 . However, it is also possible to supply a recording medium without margin perforations via a roller delivery. 
     The transport of the recording medium  10  thereby preferably occurs via a conveyor unit  25  allocated to the transfer printing station  15  in the form of conveyor belts provided with pins that engage via drive shafts into the margin perforations of the recording medium  10 . Further, a turn-over unit  28  via which the recording medium already printed on the front side is turned over for printing the backside and is resupplied to the transfer printing station  15  is arranged in the housing region of the printer device, namely in a receptacle region for the internal supply stack  23 . The turn-over unit  28  is in communication with the fixing station  18  via a return channel  29 . 
     Fundamentally, the units in the illustrated printer device are combined to form interchangeable modules or are designed as interchangeable modules. This is true both of the turn-over means  28 , the return channel  29  as well as of the electrophotographic printer module  26  with the units for the electrophotographic processor arranged therein. The developer station  14  is separately interchangeable in the electrophotographic printer module  26 . To this purpose, it is seated on rails  27  and can thus be pushed out of the printer unit perpendicular to the plane of the drawing and replaced. Its fundamental structure is disclosed by DE-C1-19540138. An identification unit  30  in the form of a flat module whose function shall be explained later is arranged on the developer station  14 . 
     The printer unit is controlled via a printer controller schematically shown in FIG. 3 whose fundamental structure is disclosed by PCT/DE95/00635. The operation of the printer unit occurs via a control panel display  31  in the form of a touch screen picture screen. 
     The identification unit  30  of FIG. 1 secured on the developer station  14  has a structure as shown in FIG.  2 . The identification arrangement is composed of a plurality of electronic modules arranged on a printed circuit board  32  that are connected to one another via control lines to a microprocessor control. An 8-bit processor with an on-chip EPROM is provided as a central unit with a corresponding main memory  33 . It is in communication with a digital-to-analog converter  34  with terminal  35  and with an analog-to-digital converter  36  with a corresponding terminal  37 . A nonvolatile memory  43  in the form of an EEPROM is also coupled to the central unit via a line. A data interface  38  sees to the connection to a communication interface that is designed as a CAN bus  39 . This CAN bus couples the identification unit  30  to the higher-ranking process controller of the device, namely the device controller  40 . 
     A plurality of toner concentration sensors  41  that were inductively and analog as well as one or more temperature sensors  42  are arranged in the developer station  14 . The toner concentration sensors  41  inductively identify that ratio of the carrier particles composed of iron to the toner particles of the developer mix, namely taking ambient temperature and page counter reading into consideration and, potentially, taking other influencing quantities into consideration. The need for fresh toner is thus identified and communicated to the device controller. This actuates the corresponding fresh toner delivery unit in the device. In order to be able to take the influencing quantities such as ambient temperature, page counter reading and, for example, page size into consideration, the operating point of the toner concentration sensors  41  is readjusted via the digital-to-analog converter  34  with its terminal  35 , whereby the digital-to-analog converter converts the digital signals of the central unit  33  into corresponding analog signals for the toner concentration sensor  41 . 
     The data about page counter reading and, potentially, page size are communicated to the central unit  33  via the device controller  40  and the CAN bus  39 . 
     The analog measured result of the toner concentration sensors  41  and of the temperature sensors  42  is supplied via the terminal  37  to the analog-to-digital converter  36  that converts the analog data into digital data for the central unit  33 . 
     The calculated measured result and, thus, the percentage relationship between carrier and toner particles is digitally deposited in the non-volatile memory  43  (EEPROM). The same is true of the data about the page counter reading or, respectively, page size supplied from the device controller  40 . The deposit of the data thereby occurs, for example, in the form of a data log listing the entire history. These data are thus always allocated to the developer station  14  firmly connected to the identification unit  30  and can be directly fetched from the non-volatile memory  43  after replacement of the developer station  14 . In order to enable this replacement, the CAN bus  39  is connected via a plug  44  to the data interface  38 . Upon replacement of the developer station  14 , the plug is released, the developer station is removed, and the new developer station is inserted and the plug connection  44  is again closed. 
     According to the illustration of FIG. 3, the device controller  40  contains a plurality of microprocessor-controlled sub-systems in the form of sub-modules. The sub-module  45  is thus responsible for the control of the paper transport; the sub-module  46  is responsible for the slip regulation of the recording medium or, respectively, the paper transport, as disclosed by PCT/DE95/00635. The sub-module  47  of the device controller controls the fixing station and the sub-module  48  controls the basic unit. The sub-module basic unit  48  controls the under-pressure, the toner concentration and supplies the central clock of the system. This sub-module  48  is coupled via the serial interface (CAN bus  39 ) to the identification unit  30 . The display unit  31  is also connected to the sub-module  48 . The aging condition of the toner identified via the toner concentration sensors  41  and the temperature sensors  42  is visually displayed thereon. The page counter reading and the entire data log stored in the non-volatile memory  43  (EEPROM) is also fetchable via the display  31 . 
     Given the illustrated exemplary embodiment, the sensors identify the aging condition of the developer mix. However, it can also be necessary to control or, respectively to acquire further parameters of the developing process. This, for example, can be the modification of the bias voltage at the developer drums. For this purpose, the central unit  33  of the identification arrangement  30  comprises a reserve terminal  49 . 
     In addition to said data, the specific identification data of the developer station are also stored in the non-volatile memory  43 . These are, for example, the serial number and the type of developer station. These data are input into the non-volatile memory  43  upon initial commissioning of the developer station and remain stored in callable fashion therein. They can be visualized with the assistance of the display unit  31  (picture screen) like the other data. 
     The assistance of the above-described identification arrangement makes it possible to utilize a plurality of developer stations in an electrophotographic printer unit dependent on the degree of usage. It is thus likewise possible given a device park with a plurality of electrophotographic printer means to select the corresponding developer station from a supply of developer stations when color printing is desired an to insert this into the printer having the color printing job that has been called. 
     The type of developer station, its aging condition and the aging condition of the developer mix are automatically called from the non-volatile memory  43  via the device controller  40  given replacement and are made available to the operator via the user interface  31 . It is also possible to call alarm procedures dependent on the content of the data log of the non-volatile memory  43 . When, for example, the developer mix has aged to such an extent that the carrier particles must be replaced because of coating (enveloping of the carrier particles, this procedures is displayed at the picture screen  31  and the printing operations are interrupted or, respectively, the startup of printing is prevented. 
     It can also be imagined to design a mobile inquiry control with which it is possible to interrogate the operating conditions of the introduced developer station by connection to this controller independent of the device controllers of the electrophotographic printer devices. 
     The invention was described above with reference to an interchangeable developer station. Of course, the inventive principle can also be applied to other interchangeable modules such as the fixing station, delivery unit, turn-over station, etc. 
     Control Panel Process Controller 
     According to the illustration of FIG. 4, a control panel process controller contains the actual display  31  and a microprocessor or PC control  50 . A touch screen control  51  serves as input unit. Instead of the touch screen input, an input via a keyboard is also possible. A memory  52  in the form of a hard disk is connected to the PC control (central unit). It serves as system memory unit for storing the system history. A further non-volatile memory  53  in which two allocation tables  54 / 1  and  54 / 2  are stored is also connected to the PC control. The allocation table  54 / 1  contains the possible operating data of the individual units such as, for example, counter reading and toner type with the allocated system data such as toner concentration given the required toner type or other electrophotography settings given the corresponding counter reading. These operating data are also stored in the identification unit  30 . The allocation table  54 / 1  sees to the corresponding allocation of one data type to one another. The identification numbers, i.e. the type of the individual units  18 ,  28 , as well as the operating data such as counter reading and toner type belonging to the identification numbers are contained in the allocation table  54 / 2 . The process controller  50  is, on the one hand, functionally coupled (data bus) to the individual sub-units  14 ,  18 ,  28  and, on the other hand, to the process controller unit  40  (device controller). In a specific embodiment of the invention, the control panel process control unit  50  can be in communication with a remote interrogation means  55  via which it is possible, for example, to interrogate the content of the memories  52  or  53  in order to obtain information about the system history at a remote service location. It is thus possible to initiate the required service measures before the actual maintenance at the device location and, for example, to order the required replacement parts. This remote interrogation unit can be designed as a standard remote interrogation unit known from data communications. 
     Function of the Control Panel Process Controller 
     As already described, the memory  53  contains two different allocation tables that are interpreted via the control panel process control unit  50 . The operating data such as toner type and counter reading are arranged in a first table row in the first allocation table  54 / 1 . The counter reading is an internal counter reading about the plurality of printed pages. It provides information about the aging condition. The corresponding system data to be called are contained in a second table row. These, for example, can be the required toner concentration given the corresponding toner type or, in general, the process data of the electrophotography process to be set given the operating data. The identification numbers of the various sub-units are stored in a first table row in the second allocation table  54 / 2 , whereby these identification numbers are either automatically stored upon insertion of the sub-units or, on the other hand, they are manually input via the input unit  51 . The operating data such as, for example, toner type and counter reading are allocated to these identification numbers. Both allocation table  54 / 1  as well as allocation table  54 / 2  are evaluated by the control panel process controller, and the system data or, respectively, operating data identified in this way are supplied to the process control arrangement (device controller)  40 . 
     When the device is run up from the quiescent condition, the device controller (process control  40 ) interrogates the sub-units  14 ,  18  or, respectively, their electronic modules  47 ,  48  for the stored operating conditions and transmits the data to the control panel unit or, respectively, to the control panel process control unit  50 . The control panel process control unit  50  compares the supplied operating data to the stored operating data. When the operating data are present or, respectively, when they correspond to the stored operating data, the corresponding system data (the toner concentration given the example of toner) are forwarded to the device controller. In case of malfunction, i.e. given faulty operating data, the control panel process control unit  50  prevents the run-up of the printer, and the control process control unit  50  displays the faulty operating condition on the display  31 . The control panel process control arrangement now automatically checks whether operating data, for example toner type, etc., from the past are stored in the allocation table  54 / 1  and offers these data on the display  31 . The operator now decides whether these data should be employed or not. When the data are employed, the corresponding operating data or, respectively, the corresponding system data are transmitted to the device controller  40 . 
     However, it is also possible that the identification unit  30  at the developer station or, respectively, at the sub-units is malfunctioning and the content of the EEPROM provided thereat can no longer be read. In this case, the operator is prompted for manual input of the corresponding sub-unit identification number via the input unit  51 . After input of the corresponding identification number, the control panel process control unit  50  checks whether the corresponding identification number is contained in the allocation table  54 / 2  or not. When it is contained, the allocated operating data such as toner type and counter reading are called and the corresponding system data are supplied to the device controller  40  via the table  54 / 1 . 
     An overall system outage due to failure of the memory hardware of a sub-unit is prevented by this automatic procedure. 
     It is also possible that a sub-unit of an older type is attached to a printer of the described type, this not yet comprising an identification unit  30  or (EEPROM). The corresponding basic unit  48  of the sub-unit recognizes this, for example, based on a coding of the sub-unit, for example in that a specific pin of a plug has no contact. In this case, a procedure similar to that just described is implemented by the device controller. The operator is again prompted to manually input the corresponding sub-unit identification number via the input unit  51 . After inputting the corresponding identification, the control panel process control unit  50  checks whether the corresponding identification number is contained in the allocation table  54 / 2  or not. When it is contained, the allocated operating data such as toner type and counter reading are called and the corresponding system data are supplied to the device controller  40  via the table  54 / 1 . When the identification number is not contained in the allocation table  54 / 2 , then the control panel control interrogates the corresponding data such as toner type, counter reading, etc., and requests manual input. Standard values, for example a contrast setting of the developer station corresponding to the toner type, that correspond to the input data can then be taken from the table  54 / 1  and employed for the printer control. 
     FIG. 6 again illustrates the above-described data transfer and the evaluation thereof with reference to the example of a developer station as a sub-unit. A controller (basic unit) allocated to the developer station recognizes, in Step S 1 , on the basis of an encoding located at the developer station whether a developer station with data memory (IS) or a station without data memory (NIS) is present. When a memory module is present, the basic unit—in Step S 2 —receives the data located on the memory module and forwards them—in Step S 3 —to the main module of the device controller  40 . A first data type is thereby an identification number of the developer station. When this ID number is known, station-specific data can already be stored in the main module or in the PC control panel connected therewith, these being employed for driving the developer station. In Step S 4 , the main module then forwards the data for this purpose to the PC control panel. In Step S 5 , another check is carried out thereat to see whether a developer station with data (IS) or one without data (NIS) is present. In the former instance, the received data are subsequently tested for plausibility (Step S 6 ); in Step S 7 , specific electrophotographic values such as a value KW for the setting of the contrast are then set dependent on the identified toner type. These values are transferred into the main module in Step S 8  and are stored there for data protection. In Step S 9 , these data for setting electrophotographic parameters are transferred into the basic unit. 
     Parallel to the transmission of the data from the main module to the PC control panel in Step S 4 , the toner-specific data are also processed within the main module in Step S 10 . Dependent on the identified toner type, electrophotographic values are delivered—in Step S 11 —to the basic unit, and the current counter reading of the developer station is also protected within the main module in Step S 12 . 
     When it is found in Step S 5  that no data store is present (NIS) at the developer station or that specific data such as the counter reading of the developer station or the toner type are not available, then these data are interrogated in Step S 12  and—in Step S 13 —corresponding standard drive values for the electrophotographic process are taken from a specific memory area of the PC control panel. In Step S 14 , these data are transferred to the main module, are stored thereat for data protection and—in Step S 15 —are supplied to the basic unit for control of the electrophotographic parameters of the developer station. 
     System History 
     As already described, an additional, non-volatile memory (hard disk  52 ) is coupled with the control panel process control arrangement  50 , each occurring error, each automatically eliminated error, each interchanged sub-unit (for example, developer station), each hardware and software modification and each serious apparatus fault and other comparable data being stored in callable fashion thereon chronologically with date and time of day and current counter reading. In case of error, the system can thus be restored at any time in conformity with the stored system condition. An error is automatically eliminated. When, for example, a communication problem arises between the control panel process control unit  50  and the device controller  40 , i.e. this communication is interrupted, then the communication is automatically restored by calling the corresponding data from the system memory unit  52 . This means that the system is synchronized and the data of the control panel are updated with the data from the system memory unit  52 . 
     Error rates are also stored in the system memory unit  52 . When, for example, one error, for example too low a toner concentration, frequently occurs in the developer station with the identification number A when it is utilized, then this error rate is stored. At the next log on of a system maintenance by docking the service technician in the process control unit  50  in service dialog, the process control arrangement reports the frequent occurrence of this error via the display  31 . The service technician can thus identify the developer station having identification number A as an unreliable sub-unit and can eliminate the error. 
     This interrogation of the system history is also possible via the remote interrogation unit  55 . For this purpose, the service technician docks into the system history from the service management that is arranged somewhere at a distance from the unit. The described warnings and the information about the error rate with allocated identification number of the sub-unit is automatically communicated to him. He can thus optimally prepare the system maintenance before actually reaching the service location with the apparatus. 
     For eliminating the error, however, other specific algorithms are also conceivable. Upon log-on of the system maintenance, thus, a check is initially carried out to see whether additional, stored data are present in the system history since the most recent system maintenance. When no new data are present, then no data can of necessity be made available for the error diagnosis. When system data have been stored in the meantime, these are interpreted in the described way. 
     Wireless Data Transmission 
     FIG. 5 shows a toner delivery unit  56  of a developer station  14  that contains a toner container  57 . The toner  59  situated therein is suctioned from the toner container  57  with a suction nozzle  58  and is supplied to further components of the developer station  14 . The suction nozzle  58  is thereby displaced along the guide rods  60  dependent on the toner filling level in the toner container  57 . An accordion bellows  61  covers the filling opening of the toner container and thus protects other components of the developer station  14  against contamination. The toner container  57  resides in a receptacle container  62  that can be pivoted into the interior of the printer via a hinge  63 . Details regarding this developer station are disclosed in U.S. Pat. No. 5,074,342 whose content is thus incorporated into the specification by reference. 
     The toner container  57  is provided with a chip card  64  that contains an electronic memory (EEPROM), a drive circuit (IC) as well as an antenna via which a wireless data transfer to a read station  65  can occur. The read station  65  can be optionally secured to the developer station  14  or to the printer housing and is connected to the process control unit  40  via a cable connection (for example, CAN bus). It can carry out both the data exchange with the chip card  64  as well as an energy supply of the chip card  65 . Details about such chip cards and read stations are disclosed, for example, in U.S. Pat. No. 5,262,712, whose content is thus likewise incorporated by reference. 
     In the illustrated exemplary embodiment, the toner type, for example, the color thereof as well as the filling level of the bottle, are stored in the memory (EEPROM) of the toner bottle. The filling level is continuously updated during operation of the printer unit in that the amount of toner removed is identified and subtracted from the initial filling level. As a result thereof, it is possible to take toner bottles partially emptied from the developer station and to re-employ them later in the same or in some other device. In a simplified embodiment, a printed page count can also be stored instead of the exact filling level, the remaining amount of toner being capable of being roughly estimated therefrom. 
     Although some of the above exemplary embodiments were described with a plugged connection (CAN bus) and others were described with wireless data transmission (IC chip), it is clear that the type of data transmission can be respectively transferred from one to another exemplary embodiment within the scope of the invention. Given a wireless data transmission, the energy can be capacitatively or inductively coupled in from the outside. Further, it can be provided to provide a central communication interface (transmitter and/or receiver) in the printer or copier device that wireless communicates with a plurality of sub-units, so that the data transmission is simplified even farther. 
     Although various minor changes and modifications might be proposed by those skilled in the art, it will be understood that our wish is to include within the claims of the patent warranted hereon all such changes and modifications as reasonably come within our contribution to the art. 
     LIST OF REFERENCE CHARACTERS 
       10  recording medium, paper 
       11  photoconductor drum 
       12  charging means 
       13  character generator 
       14  developer station 
       15  transfer printing station 
       16  cleaning station 
       17  discharge means 
       18  fixing station 
       21  delivery means 
       22  internal stacking means 
       23  supply area 
       24  delivery rollers 
       25  conveyor means 
       26  printer module 
       27  rails 
       28  turn-over means 
       29  return channel 
       30  identification arrangement 
       31  control panel 
       32  printed circuit board 
       33  central unit 
       34  digital-to-analog converter 
       35  terminal 
       36  analog-to-digital converter 
       37  terminal 
       38  data interface 
       39  can bus 
       40  device controller 
       41  toner concentration sensor 
       42  temperature sensor 
       43  non-volatile memory eeprom 
       44  plug at the can bus 
       45  paper transport sub-module 
       46  traverse 
       47  fixing station sub-module 
       48  basic unit sub-module 
       49  reserve terminal 
       50  control panel process controller 
       51  input means, touch screen, keyboard 
       52  system memory means (hard disk) 
       53  memory means for allocation tables 
       54 / 1  allocation table, operating data-system data 
       54 / 2  allocation table, identification data-operating data 
       55  remote interrogation means 
       56  toner delivery means 
       57  toner container 
       58  suction nozzle 
       59  toner 
       60  guide rods 
       61  accordion bellows 
       62  receptacle container 
       63  hinger 
       64  data store 
       65  lead station