Abstract: An image forming system includes: an image forming device that is disposed at a first conveyance path and forms an image on a recording medium that is a continuous sheet or a long sheet; a first conveyor that conveys the recording medium on the first conveyance path in a conveyance direction; an image reader that reads the image formed on the recording medium at a second conveyance path on a downstream side of the first conveyance path in the conveyance direction; a second conveyor that conveys the recording medium on the second conveyance path; and a controller that controls a speed of a drive source of the first conveyor and controls a torque of a drive source of the second conveyor.

Abstract: A control device of an image forming system including an image former that forms an image on a recording medium formed of a continuous sheet or a long sheet includes a hardware processor that calculates a width of the recording medium on a downstream side of a fixer included in the image former in a transport direction of the recording medium and outputs a shrinkage amount or a shrinkage rate of the recording medium in the transport direction due to the fixer based on the width of the recording medium and shrinkage characteristic information of the recording medium.

Abstract: A reading apparatus includes a reader, a conveyor, motors and a hardware processor. The reader reads a surface of a recording medium with an image formed. The conveyor includes rollers disposed along a conveyance path that passes through a reading area of the reader, and conveys the recording medium being laid across the rollers. The motors rotate the rollers. The hardware processor controls operations of the motors such that the rollers located farther downstream in a conveyance direction of the recording medium rotate faster. As to at least one motor of the motors, the hardware processor switches between and performs a first control to adjust a rotational speed and a second control to adjust a torque, depending on an operating state of the motor.

Abstract: A sheet conveying apparatus includes: a plurality of driving parts each connected to one end of corresponding one of a respective plurality of rotating shafts; a first torque adjuster connected to another end of each of the plurality of rotating shafts, the first torque adjuster applying first torque to the plurality of driving parts; a second torque adjuster that applies, to the driving parts, second torque for adjusting the first torque to be applied to the driving parts by the first torque adjuster; and a hardware processor that controls the second torque to be applied to the driving parts in the second torque adjuster in accordance with a number of revolutions of the driving part.

Abstract: A heating device includes rollers, a heating belt, a heater and a hardware processor. The heating belt is in partial contact with an image generation face of a recording medium and extends over the rollers and circulating in cooperation with the rollers. The heater heats the heating belt. The hardware processor modifies an area of contact between the recording medium and the heating belt. At least two rollers are disposed along a traveling direction of the heating belt and are urged to the recording medium with intermediation of the heating belt. The hardware processor modifies the area of the contact by modifying a distance between a first roller and a second roller among the at least two rollers, the first and second rollers being respectively disposed most upstream and most downstream in the travelling direction of the heating belt.

Abstract: An image forming apparatus includes the following. An upstream second conveying roller and a downstream second conveying roller form a loop on the long sheet. A deviation amount detector detects a deviation amount of the long sheet. A loop amount detector detects a loop amount in two positions in a width direction. A speed controller controls a rotating speed of the upstream second conveying roller and the downstream second conveying roller based on a deviation amount and a difference of loop amounts in two positions. Each of the upstream second conveying roller and the downstream second conveying roller includes a near roller and a far roller. The speed controller controls the rotating speed of the near roller and the far roller based on the deviation amount and the difference of the loop amounts in the two positions.

Abstract: A sheet conveying apparatus includes: a plurality of conveyors provided along a sheet conveying direction; a plurality of main driving parts that is respectively provided to the plurality of conveyors and independently drives the conveyors; an auxiliary driving part that drives the plurality of conveyors; and a transmitter that transmits driving force between the plurality of conveyors and transmits driving force of the auxiliary driving part to the plurality of conveyors.

Abstract: A heating device includes rollers, a heating belt, a heater and a hardware processor. The heating belt is in partial contact with an image generation face of a recording medium and extends over the rollers and circulating in cooperation with the rollers. The heater heats the heating belt. The hardware processor modifies an area of contact between the recording medium and the heating belt. At least two rollers are disposed along a traveling direction of the heating belt and are urged to the recording medium with intermediation of the heating belt. The hardware processor modifies the area of the contact by modifying a distance between a first roller and a second roller among the at least two rollers, the first and second rollers being respectively disposed most upstream and most downstream in the travelling direction of the heating belt.

Abstract: A sheet conveying apparatus includes: a plurality of driving parts each connected to one end of corresponding one of a respective plurality of rotating shafts; a first torque adjuster connected to another end of each of the plurality of rotating shafts, the first torque adjuster applying first torque to the plurality of driving parts; a second torque adjuster that applies, to the driving parts, second torque for adjusting the first torque to be applied to the driving parts by the first torque adjuster; and a hardware processor that controls the second torque to be applied to the driving parts in the second torque adjuster in accordance with a number of revolutions of the driving part.

Abstract: A sheet conveying apparatus includes: a plurality of conveyors provided along a sheet conveying direction; a plurality of main driving parts that is respectively provided to the plurality of conveyors and independently drives the conveyors; an auxiliary driving part that drives the plurality of conveyors; and a transmitter that transmits driving force between the plurality of conveyors and transmits driving force of the auxiliary driving part to the plurality of conveyors.

Abstract: An image forming apparatus includes: a conveyor that conveys a sheet; a detector that detects an end position of the sheet conveyed by the conveyor in a second direction orthogonal to a first direction being a conveyance direction; a corrector that corrects deviation of the sheet by moving the sheet in the second direction on the basis of a detection result of the end position of the sheet in the second direction detected by the detector, and a hardware processor that obtains variation information based on the end position of the sheet detected by the detector, and adjusts an interval of the conveyed sheet while controlling operation of the corrector on the basis of the obtained variation information.

Abstract: An image forming apparatus includes the following. An upstream second conveying roller and a downstream second conveying roller form a loop on the long sheet. A deviation amount detector detects a deviation amount of the long sheet. A loop amount detector detects a loop amount in two positions in a width direction. A speed controller controls a rotating speed of the upstream second conveying roller and the downstream second conveying roller based on a deviation amount and a difference of loop amounts in two positions. Each of the upstream second conveying roller and the downstream second conveying roller includes a near roller and a far roller. The speed controller controls the rotating speed of the near roller and the far roller based on the deviation amount and the difference of the loop amounts in the two positions.

Abstract: When changing the turn-on/off patterns, a controller of a fixing device sets a control interval of the turn-on/off pattern so as to be longer than a first period of time that does not exert any influence to a flicker value and to be shorter than a second period of time that does not exert any influence to a response to temperature control. The controller of the fixing device selects a third turn-on/off pattern in which power difference between power of a first turn-on/off pattern before the change in the turn-on/off pattern and power of a second turn-on/off pattern after the change in the turn-on/off pattern is smaller than a set reference power difference.

Abstract: An image forming apparatus detects that the temperature of a fixing member reaches a lower limit value at which the temperature once reduced by the start of a heating and fixing process to a paper turns to rise, after an image forming operation starts, and determines the type of the paper based on at least one of an elapsed time from a predetermined reference time point after the image forming operation starts to a time point at which it is detected that the temperature reaches the lower limit value, and a temperature difference between the temperature of the fixing member at the reference time point and the lower limit value.

Abstract: In an image forming apparatus according to the present invention, when an image forming operation is started from a standby state, electric power is supplied to a heater by switching to a first fixing control to turn on and off the heater to heat a heating roller with a fixed duty ratio based on the detected temperature of the heating roller, and thereafter, when detecting a state that the falling detected temperature reaches a lower limit value at which the detected temperature turns to rising, electric power is supplied to the heater by switching to a second fixing control which changes a duty ratio in accordance with a temperature difference between the detected temperature and a target control temperature.

Abstract: An image forming apparatus detects that the temperature of a fixing member reaches a lower limit value at which the temperature once reduced by the start of a heating and fixing process to a paper turns to rise, after an image forming operation starts, and determines the type of the paper based on at least one of an elapsed time from a predetermined reference time point after the image forming operation starts to a time point at which it is detected that the temperature reaches the lower limit value, and a temperature difference between the temperature of the fixing member at the reference time point and the lower limit value.

Abstract: In an image forming apparatus according to the present invention, when an image forming operation is started from a standby state, electric power is supplied to a heater by switching to a first fixing control to turn on and off the heater to heat a heating roller with a fixed duty ratio based on the detected temperature of the heating roller, and thereafter, when detecting a state that the falling detected temperature reaches a lower limit value at which the detected temperature turns to rising, electric power is supplied to the heater by switching to a second fixing control which changes a duty ratio in accordance with a temperature difference between the detected temperature and a target control temperature.

Abstract: An image forming apparatus forms decision registration mark for deciding whether or not a color registration correction for correcting color shifts in the color image carries out on an intermediate transfer belt. The decision registration mark is formed by registering four color registration marks. Color registration sensors detect a detection width of the decision registration mark along a sub scanning direction. A control portion receives the detection width of the decision registration mark and decides whether or not the color registration correction carries out based on whether or not the detection width of the decision mark detected by the detection portion exceeds the period of reference time. When the detection width of the decision mark detected by the detection portion exceeds the period of reference time, the control portion carries out the color registration correction.

Abstract: When changing the turn-on/off patterns, a controller of a fixing device sets a control interval of the turn-on/off pattern so as to be longer than a first period of time that does not exert any influence to a flicker value and to be shorter than a second period of time that does not exert any influence to a response to temperature control. The controller of the fixing device selects a third turn-on/off pattern in which power difference between power of a first turn-on/off pattern before the change in the turn-on/off pattern and power of a second turn-on/off pattern after the change in the turn-on/off pattern is smaller than a set reference power difference.

Abstract: An image forming apparatus includes a plurality of heaters 56 for heating the fixing roller 52, a plurality of temperature sensors 57 for detecting the temperatures of the areas to be heated by the plurality of heaters 56 respectively, and a control unit 11 for turning on and off the plurality of heaters 56 on the basis of the temperatures detected by the plurality of temperature sensors 57. If one of the heaters 56 is on when the area to be heated by the other heater cools down to the ON temperature, the control unit 11 turns on the other heater with the same timing as the one heater is turned off.