Abstract: An image forming apparatus includes various image forming units and a detachable paper cassette with data on its outer surface as to thickness, talc content, quality and the type of copy paper; the image forming units being controlled in accordance with the data when the cassette is changed. The apparatus also includes a device for marking a mark corresponding to the number of sheets of the copy paper used so as to detect the number of sheets remaining in the cassette.

Abstract: A scanner starts to move for preliminary scanning and an exposure lamp of the scanner turns on after a prescribed period after the start of the movement of the scanner. When a rear edge of an original of the minimum size placed on a platen is irradiated by the scanning, an amount of irradiation of the exposure lamp attains a prescribed amount since the prescribed period has passed from the turn-on thereof. Accordingly, insufficiency of an irradiation amount of the exposure lamp does not occur at the time of original size detecting operation. Thus, detection operation is speeded up and the first copy speed of the image forming apparatus is improved.

Abstract: A copying apparatus reproducing images of originals in either of a single color and a plurality of colors, and being capable of adjusting the reproduction density of originals manually or automatically. This copying apparatus comprises a selector which selects one mode from a first reproduction mode wherein images of originals are reproduced in a single color and a second reproduction mode wherein images of originals are reproduction in a plurality of colors. Further, the copying apparatus according to the present invention can select an automatic adjusting mode wherein the reproduction density is automatically adjusted in response to the selection of said first reproduction mode, and a manual adjusting mode wherein the reproduction density is manually adjusted in response to the selection of said second reproduction mode.

Abstract: An image forming apparatus including a sheet supply assembly capable of successively supplying sheet media, an image producing stage for producing an image on each of the sheet media supplied from a sheet supply, a sheet discharge roller for discharging from the image producing stage each of the sheet media each having an image produced thereon, sensors for detecting an occurrence of jamming of a sheet medium between the sheet supply and discharge assemblies, a jam counter operative to count the number of occurrences of jamming of the sheet medium, the jam counter being activated each time an occurrence of jamming is detected by any of the sensors, and a control circuit for monitoring the operational conditions of the image producing stage responsive to a sheet medium supplied from the sheet supply assembly after an occurrence of jamming of a sheet medium has been detected by any of the sensors, and disabling the jam counter depending on the monitored operational conditions of the image producing stage.

Abstract: When preliminary scanning is started, a reference signal is generated from a reference position sensor and a moving amount of the scanner is measured by counting. Change in intensity of the reflected light from a platen is detected by a first sensor according to movement of the scanner. When the detected intensity attains reference intensity, the moving amount of the scanner is stored. When the detected intensity attains again the reference intensity after it has been lower than the reference intensity, the stored moving amount of the scanner is updated. The time in which the detected intensity attains the reference intensity is measured and when it attains a predetermined time, absence of the original is determined and the scanner stops and returns. The size of the original is determined based on the moving amount of the scanner stored at that time.

Abstract: The present invention relates to an image forming apparatus such as a copying machine and the like, and more in particular to the temperature control at a fixing unit thereof. In the image forming apparatus according to the present invention, the temperature of the fixing unit is controlled to be kept at the first set point by the first temperature control structure in normal operation, and when the temperature of the fixing unit comes to reach the second set point as a result of the first temperature control structure getting out of order, the temperature of the fixing unit is controlled to be kept at the second set point by the second temperature control structure. Consequently, the temperature of the fixing unit can be controlled to be kept within a desired range even when the first temperature control means gets out of order.

Abstract: An image forming apparatus is provided and includes first and second developing units for developing a latent image which is formed on a photoconductor provided with the image forming apparatus. The control panel provides an arrangement for selecting either one of the first and second developing units for operation in the image forming apparatus. Additionally, the selection arrangement is provided so as to select the first developing unit if the developers, utilized in the first and second developing units, are of the same kind. If the developers of the first and second developing units are different from one another, the selection arrangement permits the selection of the second developing unit.

Abstract: An image forming apparatus has plural developing units which perform image forming operations with use of either one of the developing units.The image forming apparatus includes a counting arrangement for counting a respective number of times of use of the plural developing units or with respect to each of the colors of developers contained in the plural developing units. A developing unit is selected having the highest frequency in use among the developing units when the image forming apparatus is brought into the initial mode thereof.

Abstract: An image forming apparatus which comprises a photoreceptor medium supported for rotation in one direction, a charging device for forming an electrostatic latent image on the photoreceptor medium, a plurality of developing devices disposed in fact-to-face relationship with the photoreceptor medium for developing the electrostatic latent image into a visible powder image, a transfer charger for transferring the powder image onto a copying sheet, a sheet transport system for supplying the copying sheet to a transfer station where the transfer charger is dispose, a detector for detecting the color of toner material contained in each of the developing devices, and a control circuitry for causing one of the developing devices to apply the toner material of a particular color to a portion of the photoreceptor medium, which corresponds in position to a leading edge of the copying sheet, in the event that such one of the developing devices is detected as containing the toner material of that particular color.

Abstract: When paper jam occurs during copy operation, the paper feed opening (which is one of the paper feed openings 1a to 1d) in which the paper jam occurs is determined, and thus, the number of occurrences of paper jam is counted for each of the paper feed openings. When the number of occurred times of paper jam exceeds a predetermined number, the paper feed opening concerned is forbidden to be used until maintenance or other repair work is completed. If the preferred feed opening (1a) assigned the first priority is forbidden to be used, another preferential feed opening is selected based on the numbers of occurred times of paper jam in the other paper feed openings (1b to 1d). On the other hand, when paper jam occurs, a paper jam occurrence ratio is calculated for each paper feed opening based on the number of sheets and the number of occurred times of paper jam counted.

Abstract: A copying machine having a premaintenance system for maintaining various parts thereof based upon a value to be set for premaintenance of them which is renewed to that reflecting the number of copies counted from the latest maintenance to the present maintenance at least one time, which comprises a counter for counting the number of copies, a memory for memorizing the value to be set for premaintenance, a key for instructing completion of each maintenance operation and a premaintenance control means for renewing the value of premaintenance based upon the present count value counted by the counter from the latest maintenance to the present one.

Abstract: Three mounting portions are provided along a direction of rotation of a photoreceptor, on the downstream side of an eraser and a corona charger. A first developing unit, an outline unit and a second developing unit are mounted in this order from the upstream side. The units can be attached to and detached from the mounting portions. When an outline mode is designated, the color of the developing unit mounted on the downstream side of the outline unit is displayed on a display portion. When one color is designated out of the displayed colors, the developing unit of that color is operated to carry out a copying operation in the outline mode. When the color is not designated, the copying operation is carried out by a developing unit having a prescribed color mounted on the downstream side of the outline unit.

Abstract: Three mounting portions are provided along a direction of rotation of a photoreceptor with an eraser lamp and a corona charger provided on the upstream side of the mounting portions. A first developing unit, an outline unit and a second developing unit, each of which can be attached to and detached from each of the mounting portions, are mounted in this order from the upstream side. When an outline mode is selected, colors of the developing units mounted on the downstream side of the outline unit are displayed on a display portion. When there is no developing unit on the downstream side, no color is displayed, and the copying operation in the outline mode is prohibited. If there is only one developing unit on the downstream side, the copying operation is started by pressing a copying key. If there are a plurality of developing units on the downstream side, a plurality of colors are displayed, and the copying operation is prohibited until one of those colors is designated.

Abstract: The disclosure relates to an image forming apparatus capable of executing a copying operation by combining a plurality of copying conditions inclusive of at least a standard condition and a condition different from the standard condition. In the image forming apparatus, the designated condition is automatically returned to the standard condition after a lapse of predetermined time after the copying operation, but when any one of conditions different from the standard condition is entered during the copying operation, the entered condition is prohibited from being automatically returned to the standard condition or the predetermined time for automatically returning the designated condition to the standard condition is extended.

Abstract: An electrophotographic image forming apparatus capable of bringing one developing unit among a plurality of developing units thereof into an operative state.To accomplish the developing unit changeover operation in the least necessary time, control means accepts an image forming operation start signal during the developing unit changeover operation to start the image forming operation immediately after the completion of the developing unit changeover operation and accepts a selection signal selecting an another developing unit during the developing unit changeover operation.

Abstract: An electrostatic latent image formed on a surface of a photoconductor drum 61 of a copying apparatus is caused to be visible by a developing device 4. The developing device 4 comprises a toner tank 43 and a toner supply roller 44 for supplying toner to a developer container 45. A toner density in the developer container 45 is detected by a sensor 11 and a detecting circuit 1. When irregular supply of toner is requested through a switch 91, a control circuit 2 compares the detected toner density with a prescribed density and drives the roller 44 to supply toner till the detected density attains the prescribed density. If copy operation is instructed through a switch 92 during the supply of toner, the control circuit 2 permits the copy operation and the supply of toner is continued during the copy operation.