Abstract: The image forming apparatus is provided with: an image forming unit that forms an image on a medium; a speed changing unit that changes an image forming speed of the image forming unit; a detecting unit that detects a state quantity indicating a state of the image on the medium formed by the image forming unit; and an adjusting unit that adjusts an image forming condition set by the image forming unit according to a detection result of the state quantity detected by the detecting unit and a target value for the state quantity. The adjusting unit changes the target value for the state quantity according to the state quantity detected by the detecting unit after the speed changing unit changes the image forming speed.

Abstract: A developing apparatus includes a tank configured to contain a developing agent including a toner and a carrier, the tank having a discharge port configured to discharge the developing agent overflowing from the tank, a supplier configured to develop a latent image by using the toner contained in the tank, a replenisher configured to contain the developing agent and to replenish the developing agent into the tank, and a controller configured to estimate an amount of the developing agent in the tank in according with the amount of the supplied developing agent and the amount of the replenished developing agent and to execute a forced discharge for forcibly discharging the developing agent contained in the tank from the discharge port based on the estimated amount of developing agent.

Abstract: An image forming apparatus calculates the amount of staying toner based on the amount of drive of the developer roller and the amount of toner consumed for a print job performed. When the amount of staying toner exceeds a threshold, the toner is discharged. The threshold used upon completion of image stabilization is larger than that used upon completion of a print job. Even when performing image stabilization temporarily increases the amount of staying toner in the developing device, immediate toner discharge based on that condition is prevented. Thus, toner consumption can be minimized.

Abstract: In a method to control a development process and an electrographic process, at least one developer station inks a latent image on a carrier with a toner. The toner is extracted from a mixture of toner and toner particles and wherein first toner is supplied to the mixture. A characteristic value is determined for a status of the mixture from a model calculation in which a toner exchange rate and an operating aging rate are linked. The development process is at least one of monitored, controlled, or regulated depending on the characteristic value. Also in a related method for controlling a development process, a characteristic value is determined for a status of the mixture from a model calculation in which a change of a toner consumption rate for the toner within a time interval during operation of the developer station and a time constant are taken into account. At least one of monitoring, controlling, or regulating the development process depends on the characteristic value.

Abstract: The present invention aims to prevent a problem that an image on a document sheet is erased due to misdetection of a line-shaped noise. A copy machine 1 compares RGB values of a target pixel with averaged RGB values (Step S103). If only one of the RGB values has a difference that is greater than a prescribed value Ref2 (Step S103: YES), the copy machine 1 extracts the target pixel as a line-shaped noise pixel, and moves to a line-shaped noise correction (Step S108) while holding the address of the target pixel in a line-shaped noise address storing area 49b. If two of the RGB values have differences (Step S103: NO, Step S104: YES) and a difference between these two of the RGB values is no greater than a prescribed value Ref3 (Step S105: YES), the copy machine 1 extracts the target pixel as a line-shaped noise pixel, and moves to the line-shaped noise correction (Step S108) while holding the address of the target pixel in the line-shaped noise address storing area 49b.

Abstract: A color image forming apparatus that automatically switches a printing mode between a single color printing mode and a color printing mode according to requested image data stores, when capturing of image data of a print job is started, the image data in an image memory unit, starts image formation of the image data in the color printing mode as an initial state, and maintains a color printing mode regardless of the image data until the number of printed copies reach a first number of copies for operation switching determination X1. When the number of printed copies reaches X1, the color image forming apparatus compares, in a comparing unit, the number of remaining pages of the print job and a second number of copies for operation switching determination X2 stored in a number-of-pages storing unit 36 and controls the printing mode on the basis of a result of the comparison and information concerning whether the remaining image data is color image data or single color image data.

Abstract: An image forming apparatus is provided that holds counter information obtained by integrating a consumption of a consumable that depends on usage of service provided by the image forming apparatus. A log corresponding to the usage of the service is set in job log information with a synchronization flag set off. The log in the job log information, for which the synchronization flag is set off, is set on. The counter information and the job log information are output after the synchronization flag for the log having the synchronization flag set off has been set on.

Abstract: An image forming method includes detecting a toner degradation state by detecting an image density on an electrostatic latent image carrier with high sensitivity and low cost. The degraded toner is processed based on the detected information, so that the waste toner can be reduced and a good image can be obtained. An image density of an image that is transferred with a predetermined reference electric field is detected in a first detecting step. An image density of an image that is transferred with an electric field that is smaller or greater than the reference electric field is detected in a second detecting step. A processing step of processing the degraded toner is performed on the basis of the image density detected by each of the detecting steps.

Abstract: According to an embodiment of the invention, degradation of carrier in a case is detected from the number of rotations of a developing roller. A predetermined quantity of carrier is replenished every time the developing roller reaches a predetermined number of rotations. An excess developer caused by an increase in bulk through carrier replenishment is discharged from a developer discharge port. The degraded old carrier in the case is replaced by new carrier little by little.

Abstract: In a copier having an image data converter that sets the C density, the M density and the Y density to a density obtained by multiplying the density of black in the RGB system by a CMY mixture ratio and sets the K density to a density obtained by multiplying the density of black by a K mixture ratio when black in the RGB system is converted into the CMYK system, the image data converter sets the K mixture ratio to a K reference mixture ratio when TK<PHK, and sets the K mixture ratio to a K high mixture ratio that is higher than the K reference mixture ratio when TK?PHK. Here, TK is a K toner amount of consumption insufficiency which is a K toner amount to be consumed to prevent toner deterioration at the driving amount of the developing unit, and PHK is a K high predetermined value.

Abstract: An image forming apparatus which eliminates the necessity of carrying out wasteful operations such as retry of a job and therefore improves work efficiency. A print job is carried out to thereby form an image on a recording sheet. When an image abnormality formed on the recording sheet is detected, a controller temporarily suspends the print job. An operating unit displays a screen for prompting a user to input an instruction as to whether to continue the print job. The controller determines whether to continue the print job based on the instruction input by the user.

Abstract: In a method or system for controlling an electrophotographic printer or copier that has at least one developer station, a toner discharge from the developer station is detected during the print operation and a developer regeneration process is started when the detected toner discharge fulfills a predetermined first regeneration criterion. A charge image is generated on the photoconductor, the charge image is developed by the developer station, and the developed image is removed by a cleaning device without being transferred as printed onto a recording medium. New toner is introduced into the developer station. Also in accordance with the method or system for controlling an electrophotographic printer or copier that has at least two developer stations, during a print operation the print data is used to determine which developer stations are needed for printing of the data.

Abstract: A toner supplying method for supplying toner from a toner container to a developing part that causes toner to adhere to a latent image formed on a latent image carrying member and develops the latent image, includes detecting a toner amount in the developing part as being equal to or less than a predetermined toner amount value; forming a fog detecting image in a case where the toner amount in the developing part is equal to or less than the predetermined toner amount value, and detecting fog; and determining based on the detected fog whether to execute a toner ejecting process of ejecting the toner remaining in the developing part toward the latent image carrying member before supplying the toner to the developing part from the toner container.

Abstract: An information attaching unit attaches either one of carrier density information of initial developer and loose apparent density information of toner in the initial developer to a housing of a developing device. A density-information storage unit stores therein either one of the carrier density information and the loose apparent density information as electronic data. At least one of the information attaching unit and the density-information storage unit is provided before shipment of the developing device.

Abstract: An image forming apparatus is provided with: an image forming unit that forms an image on a medium according an image forming condition; a speed changing unit that changes an image forming speed of the image forming unit between a plurality of image forming speeds including a first image forming speed; an adjusting unit that adjusts the image forming condition set in the image forming unit; a measuring unit that measures an elapsed state after the image forming condition is adjusted for the last time at the first image forming speed in the image forming unit, and outputs a measured value indicative of the elapsed state; and a determination unit that determines, according to the elapsed state, whether or not to adjust the image forming condition before the image forming unit starts forming an image at the first image forming speed.

Abstract: A systems and methods for providing an image forming machine capable of monitoring the absolute charge to mass ratio of toner and dielectric thickness of a photoconductor layer on a photoconductor in an image forming device, and for providing warnings, alerts and process controls when the absolute charge to mass ratio of toner in an image forming device or the dielectric thickness of a photoconductor layer falls outside a predetermined range.

Abstract: A developing device includes a housing, a developing roller that carries developer, a supply roller for supplying the developer, a developer cartridge that accommodates the developer, a first sealing member that is provided at both ends of the developing roller, a developer passage opening provided in at least one of the housing and the developer cartridge, and a second sealing member provided in a vicinity of the developer passage opening. At least a part of the second sealing member overlaps the first sealing member in a direction in which the developer cartridge is attachable to and detachable from the housing. A portion of a shadow of the second sealing member cast in a direction, in which the developer passes through the developer passage opening, overlaps the first sealing member. The developer cartridge is attachable to and detachable from the housing at a position opposed to the developing roller.

Abstract: A photosensitive layer of a photosensitive drum is charged and a surface of the photosensitive layer is exposed at a specified density and then a development bias is applied to a development roller. An absolute value of a detection voltage is obtained from a development current sensor. It is determined whether the obtained absolute value of the detection voltage is less than a threshold which is set in advance, whereby a determination is made as to whether the charging property of toner is degraded.

Abstract: A method of compensating for printing quality of an image forming apparatus includes determining a pattern to be printed as a first pattern which is a default pattern and a second pattern obtained by changing the first pattern according to a toner stress index that represents a deteriorated degree of remaining toner, and printing the determined pattern with the remaining toner.

Abstract: In an image forming apparatus a developing device develops an electrostatic latent image on an image carrier with a developer that contains toner to obtain a toner image, a toner-amount detecting unit detects amount of toner attached to the toner image, and a toner-density detecting unit detects a density of toner in the developer. Moreover, a process control unit corrects a toner-density target value indicative of a target value of density of toner in the developer based on the amount of toner detected by the toner-amount detecting unit and the density of toner detected by the toner-density detecting unit, and a determines execution timing of next process based on corrected toner-density target value.

Abstract: A method (400) and apparatus (100) that detects carrier particles (130) in an electrophotographic device is disclosed. The apparatus may include an image carrying member (110). The image carrying member may have a first side (111) and have a second side (112) opposite from the first side. The image carrying member may be configured to operate in a direction of motion (115). The image carrying member may also be configured to transport an image on the first side. The apparatus may also include a magnet (120) coupled to the second side of the image carrying member. The magnet may have a length (122). The length of the magnet may be at an angle (124) of greater than zero and less than 90 degrees to the direction of motion of the image carrying member. The magnet may be configured to attract toner carrier particles transported on the image carrying member. The apparatus may also include a first sensor (140) coupled in proximity to the first side of the image carrying member and coupled in proximity to the magnet.

Abstract: An image forming apparatus which is capable of adjusting the color density while improving the printing efficiency. A color density adjustment value-adjusting unit adjusts a color density adjustment value in predetermined adjustment timing so as to keep colors of an image constant. A color density adjustment value-storing unit stores the color density adjustment value in advance. An adjustment timing occurrence-determining unit determines whether or not the adjustment timing occurs during execution of an image forming job. A color density adjustment value-predicting unit predicts the color density adjustment value in the adjustment timing determined to occur, based on the color density adjustment value stored in advance. The color density adjustment value-adjusting unit is adapted to adjust the color density adjustment value based on the predicted color density adjustment value.

Abstract: The image forming apparatus include: a resistance detection section (14) for measuring a volume resistivity of a two component developer (11) on a surface of a developer bearing member (12); a resistance memory section (16) for storing therein a preset volume resistivity; a resistance comparison section (15) for comparing the volume resistivity of the two component developer (11) which has been measured by the resistance detection section (14) with the preset volume resistivity stored in the resistance memory section (16); and a control section (17) for carrying out a process for replacing the two component developer or carrier if the volume resistivity of the two component developer (11) is lower than the preset volume resistivity.

Abstract: A toner deterioration judging method includes measuring a time taken for a recess formed on a toner surface to be evened due to flowability of the toner, and judging deterioration of the toner in accordance with the measured time.

Abstract: An electrostatographic printer includes a development housing for supplying developer to an image receptor, and a replenisher in communication with the development housing. In a basic state, a regular supply of developer having a first predetermined TC is supplied. In a special state, a special supply of developer having a second predetermined TC is supplied. In response to determining the printer should be in the special state, the special supply of developer is requested to be installed in the printer, such as through Internet ordering to a vendor. The vendor can also “custom-blend” a developer formulation based on transmitted machine conditions.

Abstract: A toner supply device including: a toner bottle filled with toner; and a toner supply assembly mounting mechanism having the toner bottle mounted thereon and feeding toner discharged from the toner bottle to a developing unit and supplying toner to the developing unit in accordance with the amount of toner consumed in the developing unit for the process of printing, further comprises: a toner bottle releasing mechanism which, when the amount of toner left in the toner bottle has been reduced to a predetermined level or lower, causes the toner bottle to move in the direction opposite to the direction in which the toner bottle is set into the toner supply assembly mounting mechanism and separate from the toner feed device.

Abstract: In the method, a digital image is received. A granularity model is constructed of each of the toner stations. A noise table is produced. The noise table is based on the granularity models and is adaptive to the content of the digital image. Noise is reduced in the digital image using the noise table. The digital image is divided into a plurality of color records, each corresponding to a respective toner station. The color records of the noise reduced digital image are printed using respective toner stations. Each granularity model defines a toner applied by the respective toner station.

Abstract: An image fanning apparatus includes: an image carrier, on which an electrostatic latent image is formed; a developing device, which accommodates a developer for developing the electrostatic latent image into a developer image, and which includes a developer carrier that carries the developer and supplies the developer to the image carrier; a remaining quantity calculation part that calculates a remaining quantity of the developer in the developing housing; a deterioration degree storage part that stores a relationship between the remaining quantity of the developer in the developing housing and a deterioration degree of the developer caused by the developing operation; and a life determination part that determines whether the developing device has reached an end of its life based on the remaining quantity calculated by the remaining quantity calculation part and the relationship stored in the deterioration degree storage part.

Abstract: An image forming apparatus includes: an image carrier; a developing housing that accommodates a developer for developing an electrostatic latent image into a developer image; a developer carrier, which carries the developer in the developing housing, and which supplies the developer to the image carrier; a developing bias supply part that supplies a developing bias to the developer carrier; a remaining quantity calculation part that calculates a remaining quantity of the developer in the developing housing; a deterioration grade storage part that stores a relationship between the remaining quantity of the developer in the developing housing and a deterioration degree of the developer caused by the developing operation; and a developing bias setting part that sets a value of the developing bias in accordance with the remaining quantity calculated by the remaining quantity calculation part and the relationship stored in the deterioration grade storage part.

Abstract: A system, including an improved sensor, for determining toner particle uniformity is described. The sensor measures toner particle charge, typically be having the charge on the toner particle control a current flow through the channel of a thin film transistor. By measuring the charge on many toner particles, the system determines whether sufficient toner degradation has occurred that the toner should be replaced. The sensor is particularly suitable for being formed on a thin diagnostic sheet that is input through the paper path of a printing system.

Abstract: To provide a height detection apparatus capable of detecting height information of a subject surface even in a narrow area, the height detection apparatus includes: an illumination optical system for illuminating the subject surface with a light flux emitted from a light source unit; an imaging optical system for causing the light flux reflected on the subject surface to form an image as a line image on an imaging surface; and a light detection unit disposed on the imaging surface. A light detection surface of the light detection unit is positioned in a plane rotated about a rotational axis, the rotational axis being an axis which is perpendicular to an optical axis of an optical element positioned optically closest to the light detection unit among optical elements constituting the imaging optical system, and is perpendicular to the line image to be formed by the imaging optical system.

Abstract: This invention provides an image forming apparatus capable of shortening the user's print waiting time as much as possible when it is determined that image adjustment is necessary during the image forming operation, and a control method therefor. To accomplish this, in a color image forming apparatus including a plurality of image forming stations which form toner images with a plurality of toners on the basis of a job, it is discriminated whether adjustment processing is necessary during a continuous image forming operation based on the job. If it is discriminated that adjustment processing is necessary, it is determined whether each of the image forming stations has a non-operating time enough to execute the discriminated adjustment processing during the image forming operation. The image forming station determined to have a non-operating time enough to execute adjustment processing executes the discriminated adjustment processing during the non-operating time.

Abstract: Provided are a method, system and program for checking and conditional processing of a print job printed with multiple transfer media. A print job indicates first print content to print using a first transfer medium and second print content to print using a second transfer medium. The first print content is printed onto a print medium with the first transfer medium. The printed first print content is read to determine whether the printed first print content satisfies a quality requirement. The second print content is printed onto the print medium with the second transfer medium in response to determining that the quality requirement is satisfied. Information is printed indicating an error on the print medium in response to determining that the print quality requirement is not satisfied.

Abstract: This invention provides an image forming apparatus capable of shortening the user's print waiting time as much as possible when it is determined that image adjustment is necessary during the image forming operation, and a control method therefor. To accomplish this, in a color image forming apparatus including a plurality of image forming stations which form toner images with a plurality of toners on the basis of a job, it is discriminated whether adjustment processing is necessary during a continuous image forming operation based on the job. If it is discriminated that adjustment processing is necessary, it is determined whether each of the image forming stations has a non-operating time enough to execute the discriminated adjustment processing during the image forming operation. The image forming station determined to have a non-operating time enough to execute adjustment processing executes the discriminated adjustment processing during the non-operating time.

Abstract: A method and apparatus for charging toner for an imaging device includes an inactivity determining section that determines one or more periods of inactivity of the printing machine, a measuring section that measures a charge of the toner, and a charging section that charges the toner to a predetermined level based on at least one of the determined one or more periods of inactivity and the measured charge of the toner. The toner is charged to a predetermined level after recovery from the inactivity period so that the tribo-electric charge of the toner is enhanced for normal printing without causing unwanted effects when the imagining device recovers from inactivity.

Abstract: To provide an image forming device that is capable of preventing deterioration of the image quality through preventing deterioration of the toner even if frequency of making a copy is low. The image forming device includes: a developing part having a developing roller for achieving development by electrostatically attaching a toner onto an electrostatic latent image formed on a photoreceptor; a transferring part for transferring a developed toner image to a paper; and a cleaner part for removing and collecting the toner remained on the photoreceptor after transferring, wherein the developing roller is rotary-driven at a lower speed than a speed of development under a standby state. The image forming device includes a standby-state refresh control part for forcibly consuming an amount of the toner that is calculated based on accumulated time of the low-speed rotary drive.

Abstract: A plurality of chambers are adapted to accommodate a plurality of cartridges each containing toner to be used for printing. A mode changer is operable to change an operation mode of the printing apparatus in accordance with a combination of respective colors of toner in the cartridges accommodated in the chambers. A first detector is operable to detect a residual amount of toner in each of the cartridges. A second detector is operable to detect the respective colors of toner in the cartridges when the operation mode is changed. A controller is operable to generate an image data including a plurality of first identifiers each indicative of the residual amount of toner in one of the cartridges and a plurality of second identifiers each indicative of one of the colors of toner and associated with one of the first identifiers. A display is adapted to display the image data.

Abstract: A reference developing image is formed on a photoreceptor drum under an image forming condition measured in advance, and the density of this reference developing image is detected. A development bias voltage is corrected based on the detection result, and when a correction value of the development bias voltage exceeds a predetermined range, a reference output voltage of an ATC sensor for detecting the density of toner in a developing device is corrected based on the detected value of humidity around the developing device, the frequency of use of the apparatus, and the agitation stress of developer.

Abstract: In an image forming apparatus, in each of a cyan image forming unit, a magenta image forming unit, a yellow image forming unit, and a black image forming unit, during a non-development period during which no toner is discharged out of a development unit, when toner in the development unit is agitated with an agitation roller, every time the drive time of a development motor for driving the agitation roller is counted, the drive time is stored on an accumulative basis in an EEPROM; with respect to the developer unit of which the drive time has become equal to or longer than a predetermined period, a predetermined amount of toner is supplied thereto and the predetermined amount of toner is discharged therefrom, and thereafter the stored drive time is reset.

Abstract: This is a test procedure for detecting contaminants or a method for removing contaminants from toner to be used in an electrophotographic marking system. The method simulates the mixing and separation of contaminants that occur in an actual development system. It has been determined that contaminants in toner have tribo properties that prevent strong adherence of these contaminants to the carrier whereas purified toner has tribo properties that permit stronger adherence to the carrier. A separation procedure and method is thereby used to remove or identify contaminants.

Abstract: A facsimile apparatus detects whether or not an ink ribbon internally mounted in an ribbon cassette amounted to the facsimile apparatus is a standard ink ribbon. When the apparatus detects a non-standard ink ribbon, the apparatus notifies a user by printing a message informing that the presently-mounted ink ribbon is a non-standard one and that printing function with the presently-mounted ink ribbon will be disabled after elapse of an allowable time.

Abstract: A developer container includes a developer container configured to contain a developer including a toner and a carrier, a developer delivering mechanism configured to deliver the developer toward an image bearing member of an image forming apparatus, and a detecting mechanism configured to detect deterioration of the developer based on a predetermined characteristic of the developer.

Abstract: An image forming apparatus includes: an image carrying member; a latent image forming unit to form an electrostatic latent image on the image carrying member; a developing unit to develop the electrostatic latent image on the image carrying member to form a toner image; a forcible discharge unit to forcibly discharge the toner from the developing unit; a toner supplying unit to supply toner by the discharged quantity; and a fog-detection unit to detect fog of the image, wherein the forcible discharge unit forcibly discharges the toner from the developing unit based on a detected result of the fog-detection unit.

Abstract: An image forming apparatus of the present invention includes a toner content controller configured to set the target value of a toner content sensor for determining, after a developing unit has been driven for a preselected period of time since the detection of the replacement of a toner cartridge, that a toner-end recovery operation has been completed. Subsequently, every time a preselected toner replenishing cycle is executed, the toner content controller determines whether or not the output voltage Vt of the toner content sensor has decreased below Vt10-0.1 V and determines, if the answer of this decision is positive, that a toner-end recovery operation has completed.

Abstract: A logo data generating system and logo data generating method indicate the amount of ink required to print a logo during the logo editing and creation process. The system includes a source image capture controller for capturing a source image that is the foundation for logo data creation; an image processor image that processes the captured source image to generate the logo data; an ink consumption calculator that generates user-readable attribute data indicating the amount of ink required to print the logo data from the number of color pixels in the logo data image processed by the image processor; and a display controller that displays the attribute data on a display device so that the user can recognize from the displayed attribute data how much ink is required to print the logo data being edited.

Abstract: An image forming apparatus includes a toner forced discharge treatment for executing a toner discharge mode in which toner inside a developing device is forcedly consumed, and a toner discharge judgment treatment capable of judging necessity of execution of the toner discharge mode based on a decision as to whether or not a toner state inside the developing device is in a state of leading to an image quality defect. Further, the apparatus includes a toner forced supply treatment for executing a toner supply mode in which new toner is supplied from a toner replenishment device to the developing device in addition to execution of the toner discharge mode.

Abstract: An image forming apparatus includes a developing device for developing an electrostatic latent image, formed on an image-bearing member, with toner; a developer supply container which contains developer containing toner and a carrier and is detachably mountable to a main assembly of the image forming apparatus; developer supply means for supplying the developer contained in the developer supply container to the developing-device; and developer discharge means for permitting discharge of the developer in the developing device to the outside of the developing device. To the image forming apparatus, one of plural kinds of developer supply containers containing developers having different carrier ratios in the developers is selectively mountable. The image forming apparatus further comprises notification means for providing notification of the kind of the developer supply container to be selected on the basis of information on deterioration of the carrier when the developer supply container is replaced.

Abstract: A toner current measuring device able to measure a toner current. The toner current measuring device having provided therein a toner deposit capacitor c1 including an electrode 11 and an electrode 12 disposed in opposition, a reference capacitor c2 having a mechanism for adjusting a capacitance thereof; a power supply unit 4; and a measuring unit 10 for measuring, when a voltage is applied to both capacitors to cause a transfer, between the opposing electrodes, of charged toner deposited on the electrode 11, a difference between currents flowing in the toner deposit capacitor c1 and the reference capacitor c2, the difference being measured as a toner current generated as a result of the transfer of the charged toner.

Abstract: Embodiments herein generally relate to printing systems and methods that use toner and more particularly to a system and method that observes the distribution, for different levels of transfer field, of mass per area of toner remaining on the drum/belt as the drum/belt transfers the toner. The distribution is compared to predetermined standards and/or other networked printing systems to evaluate characteristics of the toner. Actuators can then be used to improve the toner characteristics resulting in improved print quality within a printing system and improved printing consistency between internally or externally networked printing systems and/or marking engines.

Abstract: An encoder of a process unit encodes an identification code output by the CPU of a main unit, thereby obtaining a response code. The response code is returned to the main unit. The logic of the encoder is changeable. At shipment, a first logic is set in the encoder. After use, a second logic determined on the basis of a predetermined rule is set to the encoder under control of the CPU. The main unit stores the second logic set in the encoder of the process unit. The identification code is encoded by the encoder of the main unit individually with the first logic and the stored second logic, with the result that normal codes are obtained. The normal codes are collated with the response code by a collator. The CPU identifies the status of the process unit based on the result of the collation by the collator.