Abstract: The present invention relates to utilizing memory provided in a machine replaceable sub-assembly to be a medium of distribution for software code updates to that machine relating as to how that machine should operate. In one alternative, there is provided a method for operating a machine comprising the steps of providing a replaceable sub-assembly separable from the machine, the replaceable sub-assembly further comprising a wireless interface and a memory in which is stored software code of executable instructions. The method further provides communicating via the wireless interface with the replaceable subassembly to store software code of executable instructions relating to the operation of the machine into the memory. The method then provides placing the replaceable sub-assembly into the machine, reading the memory, placing the stored software code of executable instructions into the machine as new machine software code, and then operating the machine in accordance with the new software code.

Abstract: The present invention relates to utilizing memory provided in a machine replaceable sub-assembly to be a medium of distribution for software code updates to that machine relating as to how that machine should operate. In one alternative, there is provided a method for operating a machine comprising the steps of providing a replaceable sub-assembly separable from the machine, the replaceable sub-assembly further comprising a memory in which is stored software code of executable instructions. The method provides placing the replaceable sub-assembly into the machine, reading the memory, placing the stored software code of executable instructions into the machine as new machine software code, and then operating the machine in accordance with the new software code. In this way, the replaceable sub-assembly becomes the medium for the machine's software updates.

Abstract: An image forming apparatus has a double-sided image forming mode. In this mode, a paper sheet is fed to a printer section to form an image on its first side and reversed through a reversing path of a reversing mechanism. The reversed paper sheet is stacked temporarily in a temporary stacking section and fed again to the printer section by a pickup roller to form an image on its second side. The paper sheet is then ejected. If there are no sufficient paper sheets in the stacking section before the double-sided image forming mode is completed, it is determined that an accident has occurred and the double-sided image forming mode is executed again. If a paper sheet remains in the stacking section after the double-sided image forming mode is completed, it is also determined that an accident has occurred and the double-sided image forming mode is executed again.

Abstract: An image forming apparatus includes, a first speed decision unit which decides the driving speed of a drive source of a unit for printing, a magnification adjustment unit which adjusts the magnification of image information by changing the speed of the first speed decision unit, a second speed decision unit which decides the driving speed of a drive source of a carry unit to carry a printing medium, and a speed change interlock unit which changes the speed of the second speed decision unit, when the speed of the first speed decision unit is changed by the magnification adjustment unit.

Abstract: An object of the present invention is to provide an image forming apparatus that has an image bearing member voltage applying device for applying a voltage having a polarity reverse to that of the toner to the conductive portion of the image bearing member, a charging voltage applying device for applying a voltage to the charging device, a developing voltage applying device for applying a voltage to the developing device, and a transfer voltage applying device for applying only a voltage having a polarity reverse to that of the toner to the transfer device, wherein, the apparatus has a cleaning mode in which, when an image forming is not effected, the voltage is applied to the image bearing member by the image bearing member voltage applying device and the voltage applied to the transfer device from the transfer voltage applying device is turned off or made lower than the voltage applied at the image forming time.

Abstract: A method for determining a present air density for an imaging mechanism is presented. During a first time period: in a determining and storing action, a nominal air density is stored. In an increasing action, a fan input is increased until a known pressure in a cavity coupled to a fan receiving the fan input has been reached. In a determining and storing action, a nominal fan parameter is determined and stored after the known pressure is reached. During a second time period: in an increasing action, the fan input is increased until the known pressure in the cavity has been reached. In a determining action, a present fan parameter is determined after the known pressure is reached. In a calculating action, the present air density is calculated from the present fan parameter, the nominal fan parameter, and either the known pressure or the nominal air density.

Abstract: Host device (1) sends data to image forming apparatus. Image processing section (10) receives the data via interface (2). And, this data is contained in working memory (6). Then, processor (4) makes up image data from this data with font in font memory (7) according to program is program memory (5). And, the image data is contained in image memory (8). Image forming section (20) receives the image data via print engine interface (9). And, the image data is printed by print mechanism (22) under the control of controlling unit (21). Meanwhile, both of image processing section (10) and image forming section (20) are cooled by a fan (23). And, processor (4) goes into low electricity consumption mode, so as to suppress heat emission, when state judging means (44) judged that the apparatus is in an extraordinary state with signal from state detecting means (24).

Abstract: An electrophotographic cluster printing system for performing printing by using a plurality of electrophotographic recording apparatuses such as printers, facsimile machines or copying machines each capable of manifesting an image by using colored particles such as toner. The electrophotographic cluster printing system includes a plurality of electrophotograhic recording apparatuses each including a photoconductor, a charger, an exposure device, a developing device, and an image quality controller for detecting a factor concerning image quality and controlling image quality of an output image on the basis of information of the detected factor. In the system, at least two of the electrophotograhic recording apparatuses is used for printing one job and image quality of any one of the electrophotograhic recording apparatuses is controlled on the basis of detected information of the other electrophotograhic recording apparatuses.

Abstract: This invention provides an image-forming machine with a user detection system. The image-forming machine has image-forming equipment and at least one sensor. The image-forming equipment may include a photoconductor, one or more chargers, an exposure machine, a toning station, a fusing station, related equipment, and accessories. The image-forming machine may also include a sensor interface and a communication link. The sensor is monitored to detect when a user is near the image-forming machine. An output signal from the sensor indicates a user presence near the image-forming machine. A warm-up procedure is started in response to the output signal of the sensor.

Abstract: The carrying apparatus includes a carrying device for carrying an object to be carried, along a carrying route having a corner part, a control device for temporarily stopping and holding the object carried by the carrying device, and a detection device for detecting the object positioned at a corner part of the carrying route, wherein if the detection device detects the object when the control device stops carrying the object, the control device controls the carrying device such that the carrying device carries the object until the detection device does not detect the object any more and the carrying device then stops carrying the object.

Abstract: An adjustment control system compares multiple control amounts detected by a sensor with target values, thereby computing individual control amount deviations. When at least one of the control amount deviations is out of a predetermined tolerance, an operation-amount-determining section determines operation amounts for compensating the control amount deviations. When successful instances that have been used in the computed control amount deviations are available, the operation-amount-determining section executes a learning-control method that determines the operation amounts according to the control instances. When the successful instances are not available, the operation-amount-determining section executes an adaptive-control method and thereby determines the operation amounts.

Abstract: An image forming apparatus has an image forming device for forming an image on a recording material, a storing device for storing a parameter regarding an accumulation operation amount of the image forming apparatus, and a changing device for changing an image forming condition of the image forming device in accordance with the parameter.

Abstract: An image formation apparatus that loads a sheaf of originals obtained by stacking a sheaf of the originals to be copied and a sheaf of originals for front and reverse cover sheets, feeds the originals one by one from the loaded sheaf, reads the fed original and stores a read original image, reading the original images of four pages form the storage and forms the images of two pages on each of front and reverse faces of a sheet. Controlling the reading such that the original image for the cover sheet is formed on the sheet different from the sheet not for the cover sheet and such that plural sheets on which the images have been respectively formed are folded in two while being stacked.

Abstract: An non-reproducible image formation preventing apparatus has a recognition section, a storage section and a comparison/determination section. The recognition section performs recognition processing for received image data, determines whether or not the image data is an non-reproducible image, and outputs the determination result to an image formation section. The storage section stores non-reproducible image data recognized as an non-reproducible image by the recognition section. The comparison/determination section compares the non-reproducible image data stored in the storage section with an image based on input image data given through an image process section and finding a match degree therebetween. If either of the comparison/determination section and the recognition section determines that the image is an non-reproducible image, a detection signal is sent to the image formation section for stopping normal print.

Abstract: When a user changes a density adjusting value (developing contrast), and even when variations in the usage state of process characteristics (of the photosensitive body and the developing device) of the cartridge change, the amount of recording agent consumed can be suppressed to be low, and a sharp line image can be recorded. An image forming apparatus of this invention includes an edge detecting portion for detecting an edge of image data, an image data correcting portion for correcting image data inside the edge so as to decrease its density, a laser driving circuit for forming an electrostatic latent image on a photosensitive body, and a correction value determining table for acquiring an instruction value for giving an instruction to correct a density contrast, wherein a correction condition for image data changes in accordance with an instruction value.

Abstract: An image formation apparatus is provided with a photosensitive drum, an optical writing device which writes an image on the outer surface of the photosensitive drum, a developing device which develops the image using toner an intermediate transfer belt onto which the toner image on the photosensitive drum is transferred, a rotation angle detection unit which detects the rotation angle of the photosensitive drum, an eccentric detection unit which detects the amount eccentricity of the photosensitive drum from the rotary axis of the photosensitive drum, and a correction unit which, obtains eccentricity of the photosensitive drum based on the amount eccentricity, the rotation angle and the radius of the photosensitive drum, and corrects a distortion and a color offset in the toner image based on the obtained eccentricity.

Abstract: An image forming apparatus includes an image bearing member, an image forming unit for forming an image on the image bearing member and a detector for detecting the surface potential of the image bearing member, wherein a first image forming mode and a second image forming mode in which the image forming conditions of the image forming unit are different from each other can be selected, and further, the apparatus includes a controller for controlling the image forming conditions in the first and second image forming modes on the basis of the result detected by the detector for the first image forming mode.

Abstract: Method and system for predicting print quality degradation in an image forming device. Correction factors produced during calibration cycles are stored for future analysis. The correction factors, or alternatively new printer control parameters which incorporate the correction factors, may be adjusted for current environmental conditions. During the calibration cycle, the correction factors produced during the current calibration cycle and old correction factors produced during prior calibration cycles are analyzed to determine if the printer control parameters are within desired degradation limits, which indicate that the print quality of the imaging forming device will degrade beyond acceptable limits prior to the next calibration cycle. Thus, a statistical analysis of the historical data produced during calibration cycles can be used to predict when the image quality of the image printing device will degrade beyond acceptable limits.

Abstract: A compressible substrate such as paper has an image formed on the substrate. The imaged substrate is subjected to a compressive force throughout the entire area of the substrate to reduce the thickness of the substrate. The substrate remains in the reduced thickness, increased density state upon release of the compressive force.

Abstract: Light is applied by a laser diode 121 onto a photosensitive roll 110 formed with a developed toner image 161, the surface potential of the photosensitive roll 110 to which the light is applied is measured with a surface potential sensor 122, and the toner amount of the developed toner image 161 on the photosensitive roll 110 is derived based on the measured surface potential.

Abstract: An image forming device, in accordance with the present invention, stores the correction factors produced during calibration cycles for future analysis. The correction factors, or alternatively, the new printer control parameters, which incorporate the correction factors, may be adjusted for current environmental conditions. During the calibration cycle, the correction factors produced during the current calibration cycle and old correction factors produced during prior calibration cycles are analyzed to determine if the printer control parameters are within desired degradation limits, which indicate that the print quality of the imaging forming device will degrade beyond acceptable limits prior to the next calibration cycle. Thus, a statistical analysis of the historical data produced during calibration cycles can be used to predict when the image quality of the image printing device will degrade beyond acceptable limits.

Abstract: A method and apparatus to determine the use status of a customer replaceable unit (CRU) in an electrophotographic printing machine. The CRU has a customer replaceable unit monitor (CRUM) which communicates with the machine controller upon insertion of the CRU into the machine. Based on the signal generated by the CRUM the controller can determine whether the CRU has been previously used in the machine or is new. Appropriate settings and adjustments can be made based on predetermined parameters according to use. In addition, if a CRU is new a cycle can be initiated in which a toner patch is developed and not transferred so that a layer of toner is deposited on the cleaning blade. This minimizes damage to a photoreceptor belt due to lack of lubrication of the cleaner blade and chatter that may result therefrom.

Abstract: An image processing apparatus capable of color image formation with a plurality of color components, which solves a problem of increment of processing time in monochrome image formation due to correction on image formation conditions with predetermined patch formation. For this purpose, in case of monochrome image formation, even if a tonality control request flag is set, an image formation sequence is started without performing tonality control. Thus processing time can be reduced in monochrome image formation.

Abstract: In an electrophotographic imaging system, a toner density control method and apparatus that uses software modeling to instantaneously compensate for image density variations due to fluctuations in toner concentration. A time-delay model of developer housing dynamics is maintained in machine software of a controller that approximates delay between toner concentration sensing and image development, delay caused by toner-carrier mixing, and/or delay caused by transport of toner-carrier from the development housing to the developer roll. The approximations can be adjusted according to actual measurements over the last several minutes of operation. The controller compares predicted toner concentration sensor signals with averaged actual toner concentration sensor signals to detect long-term and/or short-term drift.

Abstract: An image recording apparatus has a converting device which converts a first image signal into a second image signal by employing an image signal converting condition, a recording device for recording an image by signal values of the second image signal, a measuring device for reading a test chart image recorded by the recording device by test chart output image signal values to acquire measurement density values, a selecting device for selecting reference density values corresponding to the measurement density values from target density data which indicates a relationship between the first image signal and target density of an image recorded on a recording medium, and a calculating device for calculating target image signal values based upon the target density data and the reference density values and for calculating the image signal converting condition based upon both the target image signal values and the test chart output image signal values.

Abstract: An image forming apparatus includes an LED array for performing exposure according to an input image signal, a photoconductive drum on which an electrostatic latent image is formed by exposure with the LED array, a developing device for making the electrostatic image visible, a transfer charger for transferring the visible image onto a transfer material, and a fixing device for fixing the image on the transfer material. When the operating speed in an image forming process equals the image forming speed, and the image forming speed can be switched among a plurality of levels, the image forming condition is changed in accordance with the image forming speed.

Abstract: This invention pertains to an electrographic photosensitive material comprising a blocking layer, an electroconductive substrate layer and a charge generation layer, where the blocking layer comprises TiO2 with an average particle size less than about 50 nm and a quaternary ammonium salt, and where the quaternary ammonium salt is uniformly distributed in the blocking layer and is less than about 5 wt % of the blocking layer. In another aspect, this invention pertains to an image forming apparatus for forming images on a recording medium comprising an imaging light having a wavelength and an organic photoreceptor having a blocking layer, an electroconductive substrate layer, and a charge generation layer, where the blocking layer comprises TiO2 particles and a quaternary ammonium salt, and where the quaternary ammonium salt is uniformly distributed in the blocking layer and is less than about 5 wt % of the blocking layer.

Abstract: Light is applied by a laser diode 121 onto a photosensitive roll 110 formed with a developed toner image 161, the surface potential of the photosensitive roll 110 to which the light is applied is measured with a surface potential sensor 122, and the toner amount of the developed toner image 161 on the photosensitive roll 110 is derived based on the measured surface potential.

Abstract: An object of the present invention is to provide an image forming apparatus that has an image bearing member voltage applying device for applying a voltage having the same polarity as that of the toner to the conductive portion of the image bearing member, a charging voltage applying device for applying a voltage to the charging device, a developing voltage applying device for applying a voltage to the developing device, and a transfer voltage applying device for applying only a voltage having a polarity reverse to that of the toner to the transfer device, wherein, the apparatus has a cleaning mode in which, when an image forming is not effected, the voltage is applied to the image bearing member by the image bearing member voltage applying device and the voltage applied to the transfer device from the transfer voltage applying device is turned off or made lower than the voltage applied at the image forming time.

Abstract: The present invention provides an image forming apparatus having an image forming device for forming an image on a recording material, a storing device for storing a parameter regarding an accumulation operation amount of the image forming apparatus, and a changing device for changing an image forming condition of the image forming device in accordance with the parameter.

Abstract: An image forming apparatus, method and computer program product, including a pattern detecting device configured detect whether or not a pattern is constructed with a lengthwise line of a single dot width on a basis of a pattern of respective multi-value data of a target pixel and circumferential pixels adjacent thereto in a main scanning direction; and a printing device configured to print size-reduced printing dots of the lengthwise line of the single dot width detected by the pattern detecting device.

Abstract: An image forming apparatus includes an LED array for performing exposure according to an input image signal, a photoconductive drum on which an electrostatic latent image is formed by exposure with the LED array, a developing device for making the electrostatic image visible, a transfer charger for transferring the visible image onto a transfer material, and a fixing device for fixing the image on the transfer material. When the operating speed in an image forming process equals the image forming speed, and the image forming speed can be switched among a plurality of levels, the image forming condition is changed in accordance with the image forming speed.

Abstract: An image forming apparatus includes a plurality of image bearing members, an image forming device for forming images of plural colors on the plurality of image bearing members, a recording material conveying belt for bearing and conveying a recording material thereon, a drive roller for transmitting a driving force to the recording material conveying belt, the images of plural colors on the plurality of image bearing members formed by the image forming device being successively transferred to the recording material formed on the recording material conveying belt in superposed relationship with one another, and a control device for controlling the rotating speed of the drive roller on the basis of the thickness information of the recording material conveying belt in the direction of movement of the recording material conveying belt.

Abstract: An image processing apparatus capable of color image formation with a plurality of color components, which solves a problem of increment of processing time in monochrome image formation due to correction on image formation conditions with predetermined patch formation. For this purpose, in case of monochrome image formation, even if a tonality control request flag is set, an image formation sequence is started without performing tonality control. Thus processing time can be reduced in monochrome image formation.

Abstract: In the present invention, control amounts are input from plural sensors. Good/bad determination is performed to determine whether all deviations of control amount variables are within tolerable ranges. If a determination result is “bad”, it is determined whether a position in a control amount deviation space is present in success experiences learnt at this time point. If there is the experience, a learning control using the operation amount of the success experience is executed. Otherwise, the operation amount is determined based on an adaptive control.

Abstract: An image forming apparatus in which each of first and second image forming device is in contact with surfaces of first and second image bearing members from which no after-transfer residual toner is removed includes a rotating charging member contacting first and second image bearing members, and a developing unit for developing an electrostatic image on the image bearing member and rotation controlling device rotates the second image bearing member and the charging member of the second image forming device during image formation only with the first image forming device.

Abstract: An image forming apparatus includes an image bearing member, an image forming unit for forming an image on the image bearing member and a detector for detecting the surface potential of the image bearing member, wherein a first image forming mode and a second image forming mode in which the image forming conditions of the image forming unit are different from each other can be selected, and further, the apparatus includes a controller for controlling the image forming conditions in the first and second image forming modes on the basis of the result detected by the detector for the first image forming mode.

Abstract: An image forming apparatus capable of matching, with high precision, the timing of the paper arriving at the transfer position and the timing of the toner image arriving there and not requiring the detection of the front end position of the toner image as by a sensor for the matching of the timings. The image forming apparatus has an image forming unit to make an image on image carriers, a transfer unit to transfer the image on the image carriers onto the paper, a transporting unit to transport the paper toward the transfer unit, a calculation unit to calculate a time when the image on the image carriers will arrive at the image transfer position or nearby position and correct the calculated result according to a predetermined parameter, and a control unit to control the paper transporting operation of the transporting unit according to the time determined by the calculation unit.

Abstract: Electrostatographic recording method and apparatus that includes a primary image-forming member (PIFM) which moves along a closed path at high-speed. The PIFM may be in the form of an endless belt, which has a row of image frame synchronizing indicia. The indicia are spaced from each other in the direction of movement of the PIFM. The indicia are not all uniformly spaced from one another so that an interframe area larger than other smaller interframe areas on the PIFM can exist. During a production run toner images are formed on the image frames by sensing the image frame synchronizing indicia. The larger interframe area is provided preferably at a splice or seam area to provide sufficient time for a change in a process element for which sufficient time is not available at a smaller interframe area.

Abstract: A device for adjusting tension applied to a photoreceptor belt in a printing apparatus. The tension adjusting device includes a control mechanism for controlling the operation of a driving motor such that a tension adjusting mechanism operates in three modes including a normal print mode where the tension is applied to the photoreceptor belt for normal printing, a loosened tension mode where the tension to the photoreceptor belt is loosened due to suspension of the printing operation, and a belt replace mode where the tension to the photoreceptor belt is released so that the photoreceptor belt can be replaced. For mode switching, the control mechanism controls the driving motor according to the position of the tension adjusting mechanism, detected by a sensing mechanism, or by detecting the load applied to the driving motor.

Abstract: A light source within a photocopy machine continuously shines high level, wide band fluorescent light on the photoreceptor to maintain the photoreceptor in a uniformly light-shocked condition. This constant level of light shock has no adverse effects on either the life or performance of the photoreceptor in normal operation. Thus, the photoreceptor becomes less sensitive to unintentional, uneven ambient room light and random, long lasting delta voltages within the print area are reduced so that print quality defects are minimized.

Abstract: A copier in which reading of an original is carried out simultaneously with formation, on the basis of image data obtained by the reading of the original, of a multicolored transfer image which is to be transferred onto a sheet, and conveying of the sheet is started during the formation of the transfer image, and at a transfer position, the transfer image is transferred onto the sheet. After starting of the reading of the original and before starting of the conveying of the sheet, if it is sensed, on the basis of the image data obtained by the reading of the original, that the original is a copying prohibited original, the sheet is not conveyed and copying processing is stopped.

Abstract: In conventional color digital copy machines, when copying in color mode, the polygon mirror of the laser beam scanner for black, which is driven at a higher speed than those of the other colors, is switched to a slower speed in conformity with the speed of the polygon mirrors for the other colors. However, a drawback of this structure is that, especially when switching from monochrome to color mode, the time required to obtain the first copy is lengthened, and the operating efficiency of copying is poor. In the present invention, when copying in color mode, the rotation speed of the polygon mirror of the laser scanner unit for black is not changed at all, but, by skipping certain mirror surfaces of the polygon mirror, and/or by skipping certain of a plurality of laser light sources, the scanning density of the laser scanner unit for black can be brought into conformity with that of the laser scanner units for the other colors.

Abstract: A perfecting apparatus for executing prints on double surfaces of a recording medium is capable of minimizing a blank space on the recording medium. The perfecting apparatus has a first image forming unit, disposed downstream in a carrying direction of the recording medium, for forming a toner image on one surface of the recording medium, a second image forming unit, disposed upstream in the carrying direction of the recording medium, for forming the toner image on the other surface of the recording medium, a fixing unit for fixing the toner images onto the double surfaces of the recording medium, and a control unit for controlling the first and second image forming units. The control unit controls, when in one-side printing, the first image forming unit disposed downstream in the carrying direction. A distance between the fixing unit and the first image forming unit is short, and hence the blank space on the recording medium can be minimized.

Abstract: A system and method for controlling the imaging device in a single pass multi color electrophotographic printing machine, includes a photoconductive member defining a timing aperture, the member moving along a path in a printing machine and a plurality of imaging devices, each one of the plurality of imaging devices writing a latent image on the photoconductive member. The system further includes a sensor, located adjacent the photoconductive member, to sense the aperture in the photoconductive member as it passes the sensor and generate a signal indicative thereof and a control device, which generates a timing signal for each of the plurality of imaging devices as a function of the signal generated by the sensor and a plurality of predetermined parameters.

Abstract: A video controller generates a video signal from image data on the basis of a print instruction, and an engine controller controls a laser scanner in accordance with the generated video signal to record an image on recording paper by an image forming section. A master controller of an optional master unit performs overall control of a variety of optional units, such as a paper-deck optional unit and a sorter optional unit, in dependence upon a control instruction sent from the video controller. Accordingly, it is possible to provide an image recording apparatus to which a wide variety of optional units can be connected freely without raising the cost of the main body of the apparatus.

Abstract: According to this invention, a controlled image quality is obtained without adjustment with respect to a short range of environmental changes in temperature, humidity and the like, and feedback control is easily performed for controlled variables over a long range to cope with changes with time, and the like. In the two-component non-contact development, the image density becomes stable irrespective of any environmental changes in temperature, humidity and the like when the developing bias AC voltage in the developer unit is a predetermined value. At the same developing bias AC voltage, when the rotating speed of the development roll is changed, the image density varies While making the developing bias AC voltage and the development roller rotating speed variable at the same time, a reference pattern is prepared on a banner sheet to measure the image density with an optical sensor.

Abstract: An image forming apparatus includes: a tray on which documents are stacked; a first document size detector for detecting a size of the documents stacked on the tray; a second document size detector for detecting a size of each of the documents conveyed from the tray; an automatic document feeding device having a document reading section for reading an image of each of the documents; an image forming section including a transfer material feeder for feeding transfer materials; and a controller for selecting and feeding transfer materials according to the detected document size.

Abstract: There is disclosed a printing system the printing data generation time calculating section of which calculates the time required for generating printing data on the side of the host computer. The printer warm-up time measuring section calculates warming-up time of the printer by referring to database. The warm-up command outputting section sends a warm-up command to the printer controlling section at such a time as the timing for terminating warming-up coincides with the timing for terminating the generation of printing data. Immediately after the completion of warming-up of the printer, since the printing data is transferred, power consumption in the dormant state is reduced.

Abstract: In image forming apparatus pertaining to the present invention, after a malfunction is detected, the control of the image forming apparatus is carried out while isolating the malfunctioning device from said control, so that the image forming operation can be performed. It is determined whether a condition governing continued image forming exists during said isolating control. If said certain condition does not exist, the image forming operation is allowed to continue. Where said certain condition does exist, the image forming operation is suspended and subsequent image forming operations are prohibited, or a maintenance call request is displayed.