Abstract: A processing time necessary for processing an image processing command to be processed is calculated and displayed. The processing time is successively subtracted as the processing proceeds, and the processing time required for the remain is displayed. This permits the operator easy grasp of the progress of processing, and therefore the operation efficiency can be increased.

Abstract: An image forming apparatus including a photosensitive drum, a discharging device for discharging an electric charge on the photosensitive drum, a process unit detachably provided in a main body of the apparatus, a driving circuit for driving the discharging device, a detecting circuit for detecting a driving current when the discharging device is driven by the driving circuit, and a determining portion for determining a mounting state and the suitability of the process unit in the main body of the apparatus. Therefore, suitability of the process unit and attachment to the main body of the apparatus is electrically determined.

Abstract: An image forming apparatus has a detachably mounted processing unit on a main body of the apparatus. The processing unit includes the image bearing member and a processing device for acting on the image bearing member to form an image on the image bearing member. The processing unit is replaced with a new processing unit when the service life of the processing unit expires. The image forming apparatus also has a first memory for storing the amount of use of the processing unit, a second memory for storing maintenance message information for replacing the processing unit with a new processing unit when the service life of the mounted processing unit expires and a causing device for causing the processing device of the processing unit to form the maintenance message information stored in the second memory on the image bearing member when the amount of use reaches a predetermined value.

Abstract: An image forming apparatus is so constructed that, even when, during a portion of a processing for feeding the medium from one of a plurality of medium storage sections, the medium storage section involved becomes empty in the case where there exists, in the other medium storage section or sections, those mediums equal to or greater than the aforementioned medium which are not to be continuously fed, it is possible to continuously feed a medium from the medium storage section only arbitrarily selected in accordance with the order of priority.

Abstract: An image forming apparatus in which parts of an image forming portion are formed as modular units, including, a section for driving the image forming portion, a section for detecting a signal representing a torque of the driving section, and a section for discriminating the attachment or detachment of the modular parts of the image forming portion according to the signal representing the torque detected by the detecting section. The load on the driving section, which is changed by the attachment of the modular parts of the image forming portion, is measured, and the attachment of a plurality of units can be checked by means of one attachment/detachment sensor without using many sensors for respective parts or units.

Abstract: An image forming apparatus as provided which receives image data supplied from a host unit and forms an image on an image forming medium. Even if a desired image forming medium is not present, the received image data is edited to allow a desired image to be formed on an arbitrary image forming medium as a substitute for the desired image forming medium.

Abstract: An image forming apparatus is provided which forms an image on a sheet on the basis of image data selectively received from a plurality of host apparatuses. The image forming apparatus comprises a plurality of input/output ports, connected to the respective host apparatuses for receiving image data from the host apparatuses, keys for setting priority orders of the plurality of input/output ports, memories for storing the priority orders set by the keys, and a CPU for selecting one of the input/output ports in accordance with the priority orders stored in the memories, if image data is received simultaneously from two or more of the host apparatuses, a memory and photosensitive assembly for receiving image data from the input/output ports selected by the keys and for forming an image corresponding to the received image data.

Abstract: In an image forming apparatus, a developing unit for developing a latent image on a photosensitive drum is detachably mounted in the apparatus and is provided with a identification signal generator for each particular developing unit. When the developing unit is replaced by a new one, an identification signal generated from the generator is compared in a CPU with reference identification data stored in a memory. When the generated identification signal differs from the stored reference identification data, the generated identification signal is stored as a new reference data in the memory and a toner concentration signal generated from the sensor is also stored as new reference toner concentration data in the memory. Thus, a desired toner concentration can be maintained even through developing units are replaced.

Abstract: An image forming apparatus has a first paper sheets supply system for supplying first paper sheets to a transfer section and a second paper sheets supply system for supplying second paper sheets to the transfer section. Either of the first and second paper sheets supply systems is selected in response to information applied from a control section. Information of paper sheet supply intervals set for the first and second paper sheets supply systems is stored in a memory.

Abstract: An image forming apparatus including a main body and a processing unit detachably mounted in the main body. The processing unit includes at least one of an image bearing member and developing device. The number of image forming repetitions of the processing unit are counted by a counter in the main body. When the counted number for the processing unit reaches a reference value representing the effective life of the processing unit, an alarm device actuates to notify the user that the effective life of the processing unit has been reached.

Abstract: An image forming apparatus includes a paper delivery detecting switch provided near the paper delivery opening, a paper presence detecting structure to detect the presence of the paper on the receiving tray, a counter circuit and a comparator. The counter circuit counts up the number of delivered paper on the receiving tray in response to a delivered paper signal from the paper delivery detecting switch and a paper presence signal from the paper presence detecting structure. The comparator compares the value of number of delivered paper counted up by the counter circuit and a delivery quantity limit value preset in the apparatus main body, and halts the image forming operation when the two values coincide.

Abstract: An optical system drive device for an image formation apparatus has a drive mechanism for reciprocally driving an exposure unit, and a pulse motor for supplying pulses to the drive mechanism. The pulses to be supplied to the pulse motor are stored in advance in a ROM. In accordance with either document size or required equal size, reduced scale or enlarged copying mode, a microprocessor reads out a predetermined control pulse from the ROM and applies it to the pulse motor, thereby controlling acceleration, constant velocity drive and deceleration of the pulse motor.

Abstract: A pulse motor driving apparatus has a drive circuit for supplying driving pulses to a pulse motor. This drive circuit switches over the exciting winding phases of the pulse motor on a two-phase unit basis, in response to the exciting phase data supplied by a microprocessor in the driving mode, thereby driving the motor by two-phase excitation. The microprocessor specifies only one of the exciting phases in the stopping mode, so that the pulse motor is stopped by single-phase excitation.

Abstract: A pulse motor-driving circuit is disclosed, which circuit includes first and second exciting coils inductively coupled to each other, and first and second switching transistors for alternately exciting the exciting coils, through a D.C. power source. A Zener diode is connected to each of the switching transistors, for suppressing a transient voltage to be impressed on the switching transistors, when the excitations of the exciting coils are changed.

Abstract: A pulse motor driving apparatus for the optical unit in a copying machine includes an excitation phase designating circuit for designating phase windings alternately from one phase to two phases and from two phases to one phase at the time of original scanning or forward rotation, and also designating the phase windings in pairs with every two phases at the time of return of the optical unit or reverse rotation. A drive circuit supplies drive pulses successively to the phase windings designated by the excitation phase designating circuit to rotate a pulse motor faster at the time of reverse rotation than at the time of forward rotation.