Abstract: An EGR-gas flow rate estimation apparatus for an engine including an exhaust circulation pipe connected between an exhaust passage and an intake passage of the engine, and an EGR control valve interposed in the exhaust circulation pipe and having a throttle portion. The apparatus estimates a provisional EGR gas flow rate Gegr0 by use of a general formula Gegr0=Aegr·(2·Pex·?a)1/2·? (?=(((?/(??1)·((Pb/Pex)2/??(Pb/Pex)(1+1/?)))1/2) where Pup represents the exhaust pressure, Pb represents the intake pressure, Aegr represents the effective opening area of the throttle portion, ?a represents the density of EGR gas, and ? represents the specific heat ratio of EGR gas. Subsequently, the apparatus estimates the flow rate Gegr of EGR gas flowing into the intake passage, by multiplying the provisional EGR gas flow rate Gegr0 by a correction value dPgain corresponding to differential pressure (Pex?Pb).

Abstract: An EGR-gas flow rate estimation apparatus for an engine including an exhaust circulation pipe connected between an exhaust passage and an intake passage of the engine, and an EGR control valve interposed in the exhaust circulation pipe and having a throttle portion. The apparatus estimates a provisional EGR gas flow rate Gegr0 by use of a general formula Gegr0=Aegr·(2·Pex·&rgr;a)1/2·&PHgr; (&PHgr;=(((&kgr;/(&kgr;−1)·((Pb/Pex)2/&kgr;−(Pb/Pex)(1+1/&kgr;)))1/2) where Pup represents the exhaust pressure, Pb represents the intake pressure, Aegr represents the effective opening area of the throttle portion, &rgr;a represents the density of EGR gas, and &kgr; represents the specific heat ratio of EGR gas. Subsequently, the apparatus estimates the flow rate Gegr of EGR gas flowing into the intake passage, by multiplying the provisional EGR gas flow rate Gegr0 by a correction value dPgain corresponding to differential pressure (Pex−Pb).

Abstract: An image forming apparatus supervisory system is provided. The image forming apparatus supervisory system includes an image forming apparatus and a control device. The image forming apparatus has an input unit for inputting an identification code and a transmission unit for transmitting the identification code. The control device is connected to the image forming apparatus, and has a reception unit for receiving the identification code and a transmission unit for transmitting to the image forming apparatus a signal for informing the image forming apparatus of a permitted number of time an image can be formed in response to receipt of the identification code. Upon receipt of the signal from the control device, the image forming apparatus permits forming an image the permitted number of times.

Abstract: An image forming apparatus is provided with print request controls for accepting a print request relevant to a job from an operator on condition that use of an image forming section is permitted by permission controls. The image forming apparatus is also provided with print controls for making the image forming section execute image formation relevant to the above job according to instructions by the print request controls. The image forming apparatus is further provided with inhibition controls for inhibiting acceptance of a print request relevant to a job different from the above job by the print request controls, regardless of the presence or absence of permission by the permission controls after accepting the print request relevant to the above job by the print request controls. Thereby, it is possible to prevent another person from opportunistically using the apparatus even when the operator forgets to cancel the permission of use of the image forming section by the permission controls.

Abstract: The invention provides an image forming apparatus such as a coin-operated copy machine, which has an upper limit value to the number of copies which are authorized to be made and which also copies both sides of originals fed to the image forming apparatus. The image forming apparatus is configured so that its intermediate tray, which temporarily stores sheets copied on their first side, is empty at the end of a copy cycle and despite the image forming apparatus being fed more double-sided originals to copy than are authorized to be copied. The image forming apparatus compares the upper limit value of the number of copies authorized to be made to the number of single-sided copies already made in the current copying cycle and begins copying the second side of the originals onto sheets from the intermediate tray when the upper limit value equals a constant K plus twice the number of images formed.

Abstract: A host computer is connected to a copying machine through communication lines. The copying machine includes an management apparatus which is provided with a card reader. Using the card reader, a section code stored in a user ID card is read and is compared with section codes previously registered in the management apparatus. When the section code of the user ID card matches one of the section codes registered in advance, copying operation is allowed and the section code and the number of copying operations are stored as management data in a registration table stored in an SRAM. When the amount of available storage space becomes less than the predetermined amount, the management apparatus transmits the registered management data to the host computer through the communication lines, clears the storage area and waits for next registrations. The host computer has an accumulating table which is capable of storing the numbers of copying operations for all the sections subjected to management.

Abstract: A group code which is a code indicating a user group, an identification code which is a unique code assigned to each group, and image formation frequency data which is data indicating a frequency of image forming operations by each group are stored in a storage unit, related to each other. After receiving an identification code from an input unit, an identification code judging unit judges whether the received identification code matches any identification code stored in the storage unit. If an identification code judging unit judges that the received identification code matches a stored identification code, a calculating unit calculates the frequency of image forming operations performed after the identification code is received, and the image formation frequency data of the group in the storage unit corresponding to the received identification code is rewritten according to the frequency of image forming operations calculated by the calculating unit.

Abstract: In an operation for transporting a sheet by a first roller to a second roller pair downstream of the first roller, and further transporting the sheet by the second roller pair, a the time during which the sheet is transported by the first roller is controlled, responsive to the number of sheets which have been fed by the first roller, to suppress disadvantages such as jamming and deformation into a Z-form, which may be caused by reduction of a transporting performance due to wear of the rollers and adhesion of paper powder to the rollers.

Abstract: A copier supervisory control system in which a plurality of copiers are connected to each other over a network is provided. Each of the plurality of copiers has a structure that compares a user identifier inputted by a user with a registered identifier. If the user identifier and the registered identifier are identical, the user is permitted to make copies by the copier. If the two compared identifiers are not identical, the user is prohibited from making copies. More specifically, a first copier receives a user identifier and compares it with its registered identifier. If the user identifier and the registered identifier of the first copier are not identical, the copier inquires of a second copier whether it has a registered identifier identical to the user identifier over the network. Upon receipt of the inquiry, the second copier compares the user identifier with its own identifier, and if the two identifiers are identical, it informs the first copier of the result over the network.

Abstract: In an image processing apparatus, determination is made whether an interruptive print wait state is attained during interruptive printing. When determination is made that the apparatus is in an interruptive print wait state, an interruption recover process is effected. Then, the apparatus returns to the normal mode prior to interruption. Thus, an image processing apparatus is provided that can have the waiting time caused by an interruption in the normal job reduced.

Abstract: In an operation for transporting a sheet by a first roller to a second roller pair downstream of the first roller, and further transporting the sheet by the second roller pair, the time during which the sheet is transported by the first roller is controlled, responsive to a comparison of a reference time and the actual time required for a sheet to be transported from the first roller to a predetermined position in the sheet transport path, to suppress disadvantages such as jamming and deformation into a Z-form, which may be caused by reduction of a transporting performance due to wear of the rollers and adhesion of paper powder to the rollers.

Abstract: In an operation for transporting a sheet by a first roller to a second roller pair downstream the first roller, and further transporting the sheet by the second roller pair, a transport speed of the sheet transported by the first roller is controlled to suppress disadvantages such as jamming and deformation into a Z-form, which may be caused by reduction of a transporting performance due to wear of the rollers and adhesion of paper powder to the rollers.