Abstract: The invention relates to a power supply device and a communication system. The power supply device supplies power to a main device. The communication system is provided with the main device mounting the power supply device therein and an external device connected to the main device. A feature of the invention is to offer a power supply device and a communication system that are capable of being responsive to external signals for returning to a normal operation mode with minimum power consumption in a power-saving operation mode. In the power saving operation mode, a main power supply circuit (60) is turned off and only an auxiliary power supply circuit (50) is operated.

Abstract: The invention relates to a power supply device and a communication system. The power supply device supplies power to a main device. The communication system is provided with the main device mounting the power supply device therein and an external device connected to the main device. A feature of the invention is to offer a power supply device and a communication system that are capable of being responsive to external signals for returning to a normal operation mode with minimum power consumption in a power-saving operation mode. In the power saving operation mode, a main power supply circuit (60) is turned off and only an auxiliary power supply circuit (50) is operated.

Abstract: An image forming apparatus includes a main power supply section, an auxiliary power supply section, a plurality of sensors, and a power control section. The sensors are disposed at a plurality of positions. The sensors change output levels thereof upon detection of a user's operation for initiating an image forming process. The power control section switches the apparatus from a normal operation mode to the power-saving operation mode after a predetermined time period during which no image forming process is performed. The power control section detects the respective output levels of the sensors through sequential power supply from the auxiliary power supply section to the sensors. The power control section switches the apparatus to the normal operation mode upon detection of a change in output level of either one of the sensors.

Abstract: A multi-function printer (MFP) has a main control circuit for setting the operation mode of the apparatus to either a normal operation mode or a power-saving operation mode. There are provided a main power supply circuit and an auxiliary power supply circuit for supplying power to the main control circuit in the normal operation mode and in the power-saving operation mode, respectively. The MFP also has a power detection circuit for detecting a state of power supply from the main power supply circuit to the main control circuit. If a power-save request is followed by a start-up request, when an amount of power detected by the power detection circuit is greater than a predetermined value, the main control circuit stops an operation relating to the power-save request and initiates an operation according to a start-up request.

Abstract: In the correction of the quantity of light of a light source used in an image reader which irradiates an original document with the light source, receives the reflected light by a CCD and reads the original document image, at the time of a document moving mode in which the document moves, correction of the quantity of irradiation light of the light source is performed by reading a first standard white board which extends over the whole area in the main scanning direction, prior to the initiation of readout of the moving document, and upon initiation of readout of the moving document, a second standard white board arranged outside the document passing area is read by using the same light source, with the read operation of the moving document, and correction of the quantity of irradiation light of the light source is performed based on the reflected light from the second white board.

Abstract: An image forming apparatus includes a main power supply section, an auxiliary power supply section, a plurality of sensors, and a power control section. The sensors are disposed at a plurality of positions. The sensors change output levels thereof upon detection of a user's operation for initiating an image forming process. The power control section switches the apparatus from a normal operation mode to the power-saving operation mode after a predetermined time period during which no image forming process is performed. The power control section detects the respective output levels of the sensors through sequential power supply from the auxiliary power supply section to the sensors. The power control section switches the apparatus to the normal operation mode upon detection of a change in output level of either one of the sensors.

Abstract: A multi-function printer (MFP) has a main control circuit for setting the operation mode of the apparatus to either a normal operation mode or a power-saving operation mode. There are provided a main power supply circuit and an auxiliary power supply circuit for supplying power to the main control circuit in the normal operation mode and in the power-saving operation mode, respectively. The MFP also has a power detection circuit for detecting a state of power supply from the main power supply circuit to the main control circuit. If a power-save request is followed by a start-up request, when an amount of power detected by the power detection circuit is greater than a predetermined value, the main control circuit stops an operation relating to the power-save request and initiates an operation according to a start-up request.

Abstract: An image forming apparatus includes an image forming unit, a paper transport unit, and a control unit for supplying the image forming unit with image data for a plurality of pages so that the image forming unit forms images page by page on sheets transported by the paper transport unit, wherein, when the image data for each page includes data representative of blanks on a leading end side and on a tail end side of the page in a paper transport direction, the control unit deletes the data representative of the blank either on the leading end side or on the tail end side from the image data prior to supplying the image forming unit with the image data, and controls the paper transport unit so that a plurality of sheets are transported sequentially to the image formation unit in a multiple state in which one sheet partially overlaps with another in the paper transport direction by a length corresponding to the deleted data representative of the blank.

Abstract: An image forming apparatus includes an image forming unit, a paper transport unit, and a control unit for supplying the image forming unit with image data for a plurality of pages so that the image forming unit forms images page by page on sheets transported by the paper transport unit, wherein, when the image data for each page includes data representative of blanks on a leading end side and on a tail end side of the page in a paper transport direction, the control unit deletes the data representative of the blank either on the leading end side or on the tail end side from the image data prior to supplying the image forming unit with the image data, and controls the paper transport unit so that a plurality of sheets are transported sequentially to the image formation unit in a multiple state in which one sheet partially overlaps with another in the paper transport direction by a length corresponding to the deleted data representative of the blank.

Abstract: When the phase control is effected on a supply voltage to a load having positive resistance characteristics with respect to temperatures before a current is allowed to pass, a voltage is supplied for a current passing time T1, and the voltage is supplied for a current passing time T2 longer than the current passing time T1, and the voltage is supplied for a current passing time T3 shorter than the current passing time T2. Also, a second control pattern is effected at least once, in which the current is passed while the current passing time is kept substantially constant, then the current passing time is extended before the attenuation rate of the peak value of the resulting load current saturates, and then the current is passed while the extended current passing time is kept substantially constant. Consequently, a voltage drop can be reduced effectively without causing large distortion of the current waveform or large conduction noise by omitting an expensive noise filter or special hardware.

Abstract: The control circuit includes: a series circuit of a first triac and a reactor; and a second triac in parallel with this series circuit so as to perform control of activation of a fixing heater. Since the fixing heater has a low resistance when the power switch is first turned on, the first triac is operated to perform phase angle control of current flow, and when the phase angle has become approximately equal to 180.degree., the first triac is stopped, at the same time the second triac starts to be operated. The switching from the first triac to the second triac is made quickly so that it is possible to reduce the power consumption from the reactor.

Abstract: A document platen driving device is provided with an endless gear connected to a document platen, whereon a document is placed, which reciprocates. A sun gear is secured to a fixed station within a space surrounded by the endless rack, and a planetary gear meshing with the endless rack and with the sun gear is also provided within the space. The planetary gear is a double gear composed of a large gear and a small gear having different pitch circle diameters. It is arranged such that the document platen is moved forward by meshing the small gear with the endless rack, and moved backward by meshing the large gear with the endless rack. In this arrangement, the backward moving speed of the document platen can be set faster than the forward moving speed, thereby permitting a reduction of the entire time required for a copying process, especially for a successive copying process.

Abstract: A document platen on which a document is placed is movably installed on the main body of a copying machine. A motor for producing a driving force is provided. An input gear to which the driving force is transmitted is located in a fixed position. A planetary gear is positioned such that it engages with and moves around the input gear. An endless gear is connected to the document platen. The endless gear has internal teeth in the form of a closed loop which engages with the planetary gear. When the planetary gear, which engages with both the input gear and the endless gear, moves around the input gear once, one reciprocating movement of the document platen is caused. With this configuration, since there is no need to provide a switching mechanism including clutches and solenoids that is used in a conventional device, the number of components is reduced, and thereby decreasing the manufacturing costs.