JPH07261603A - Image forming device and recording medium carrying method thereof - Google Patents

Abstract

PURPOSE:To make use of a prefed recording medium as a recording medium for the next image recording without discard, without any trouble. CONSTITUTION:This image forming device is provided with a carrying roller 28 carrying the recording medium after being prefed to a position detected by a resist sensor 7 and then, passing through a fixing unit 14 without having the record of the image to return to a fixed feed starring position via a return path RT and constituted so that the recording medium after being prefed to a fixing position and then, passing through the fixing unit 14 without having the record of the image is carried to return to the position detected by a sensor 29 via the return path RT.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a pre-feed function of pre-feeding a recording medium to a predetermined position before starting image recording, and a recording medium feeding method for the image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, in this type of image forming apparatus,
When the pre-fed paper was not printed within the time limit, the paper was deformed by staying in the transport path, and even if it was printed again, image unevenness would occur, so it was automatically discharged and discarded. .

Further, the paper that has been once fed is always discharged regardless of whether or not it is printed. For items that have print cancels,
It was discarded as it was.

On the other hand, in an image forming apparatus having a means (return mechanism) for returning the paper to the paper feeding portion, the paper is fixed at a constant temperature regardless of the number of times the paper has passed through the fixing device.

[0005]

However, the conventional example has a drawback that the paper is wasted. Also, since the paper that has passed through the fixing device is fixed at the same temperature,
It was wasting power.

The present invention has been made to solve the above problems, and a first object of the present invention is to pass a recording medium, which has not been image-recorded even if it is pre-fed to a predetermined position, through a fixing means. An object of the present invention is to provide an image forming apparatus which can be used as a recording medium for the next image recording without discarding the previously fed recording medium by returning and feeding the recording medium to a predetermined feeding start position.

A second purpose is to return the recording medium to the predetermined feeding start position by passing the recording medium through the fixing means when the predetermined time has elapsed without recording an image after the pre-feeding to the predetermined position. It is an object of the present invention to provide an image forming apparatus that can be used as a recording medium for the next image recording without any trouble without discarding the recording medium that has been fed in advance.

A third purpose is to allow the recording medium to pass through the fixing means for a predetermined time when a predetermined time variably set by the ambient temperature has passed without image recording after being pre-fed to a predetermined position. Provided is an image forming apparatus which can be used as a recording medium at the time of the next image recording without being affected by environmental conditions without any trouble by discarding the previously fed recording medium by returning to the feeding start position and feeding. That is.

A fourth object is that a recording medium on which an image has not been recorded even if it is pre-fed to a predetermined position is passed through the fixing means and is passed through the double-sided / multiplexing conveying path from the fixing section to the intermediate tray. By returning to the feeding start position of
It is an object of the present invention to provide an inexpensive image forming apparatus that can be used as a recording medium at the time of recording the next image without discarding the recording medium fed in advance.

A fifth object is to start feeding a recording medium, which has not been image-recorded even if it has been pre-fed to a predetermined position, through a return conveying path that extends from the downstream side of the fixing means to the upstream side of the sheet feeding. It is an object of the present invention to provide an inexpensive image forming apparatus that can be used as a recording medium for the next image recording without discarding the recording medium that has been previously fed by returning to the position and feeding.

A sixth object is to feed a recording medium, which has not been image-recorded even if it has been pre-fed to a predetermined position, through a paper ejection conveying path which is ejected from the fixing means and communicates with a paper feed stacking section. An object of the present invention is to provide an inexpensive image forming apparatus which can be used as a recording medium for the next image recording without discarding the previously fed recording medium by returning and feeding the recording medium to the feeding start position.

A seventh object is that when a predetermined time elapses without image recording after being pre-fed to a predetermined position, the pre-fed recording medium is fed from the upstream side of the transfer section to the sheet feeding and stacking section. An image forming apparatus that can be used as a recording medium for the next image recording without any trouble without discarding the previously fed recording medium by returning and feeding the recording medium to a predetermined feeding start position via a return conveyance path leading to Is to provide.

An eighth object is that the recording medium to be fed is the first.
It is determined whether the image recording of the first side or the second side is performed, and the image fixing temperature is changed between the image recording of the first side and the image recording of the second side with respect to the recording medium. An object of the present invention is to provide an image forming apparatus capable of controlling the power consumption of the fixing unit at the time of image fixing processing with respect to the surface.

A ninth object is that the recording medium to be fed is the first.
It is determined whether the image recording of the first side or the second side is performed, and the image fixing temperature is changed between the image recording of the first side and the image recording of the second side with respect to the recording medium. An object of the present invention is to provide an image forming apparatus capable of reducing the power consumption of the fixing unit during the image fixing process with the surface.

A tenth object is to judge whether the fed recording medium is the image recording for the first side or the image recording for the second side, and to record the image on the first side and the second side for the recording medium. After changing the image fixing temperature for image recording and then switching to the image fixing temperature for the first side again according to the image recording waiting time, after the image fixing temperature for the second side was set, the state in which no image was recorded continued for a while. An object is to provide an image forming apparatus that can perform stable image fixing even in the case.

An eleventh object is to judge whether the recording medium to be fed is the image recording for the first side or the image recording for the second side, and to record the image on the first side and the second side for the recording medium. By changing the image fixing temperature with image recording,
An object of the present invention is to provide an image forming apparatus capable of reducing the power consumption of a fixing roller unit including a heater for heating a fixing roller during image fixing processing on the first and second surfaces.

A twelfth object is to judge whether the fed recording medium is the image recording for the first side or the image recording for the second side, and to record the image on the first side and the second side for the recording medium. By changing the image fixing temperature with image recording,
An object of the present invention is to provide an image forming apparatus capable of remarkably reducing the power consumption of a fixing unit including a ceramic heater for heating a fixing film during image fixing processing for the first and second surfaces.

A thirteenth object is to return the recording medium to a predetermined feeding start position by passing the recording medium through a fixing means when a predetermined time has elapsed without image recording after being pre-fed to the predetermined position. It is an object of the present invention to provide a recording medium feeding method of an image forming apparatus which can be used as a recording medium for the next image recording without any trouble by discarding the previously fed recording medium by sending the recording medium.

[0019]

In a first image forming apparatus according to the present invention, after the sheet is pre-fed to the predetermined position, an image is not recorded on the recording medium that has passed through the fixing unit. A return feeding unit that returns the sheet to a predetermined feeding start position via the conveyance path is provided.

In the second image forming apparatus according to the present invention, the recording medium, which has been pre-fed at the predetermined position and then passed through the fixing means without being recorded with an image, is predetermined through a predetermined inner conveying path. And a return feeding means for feeding back to the feeding start position, and a predetermined permissible time until the image recording is canceled without receiving the image recording permission from the data source after being pre-fed at the predetermined position. Timing means, determination means for determining whether or not the previously fed recording medium can be fed back from the timed state by the timing means, and drive of the return feeding means is controlled based on the determination result of this determination means. And a control means for controlling the operation.

In the third image forming apparatus according to the present invention, the return feeding means for feeding back the recording medium pre-fed to the predetermined position to the predetermined feeding start position via the predetermined inner conveying path. A time measuring means for measuring a predetermined stop time of the recording medium pre-fed to the predetermined position, a temperature detecting means for detecting a temperature in the vicinity of the fed recording medium, and a temperature detected by the temperature detecting means. Based on the setting means for variably setting the predetermined stop time measured by the time measuring means, it is determined whether the time measuring means measures the predetermined stop time set by the setting means, and the return feeding means is provided. And a control means for controlling the driving of the.

In the fourth image forming apparatus according to the present invention, the predetermined inner conveying path is composed of a double-sided / multiplexing conveying path leading from the fixing section to the intermediate tray.

In the fifth image forming apparatus according to the present invention, the predetermined inner conveyance path is constituted by a return conveyance path which extends from the downstream side of the fixing section to the upstream side of the sheet feeding.

In the sixth image forming apparatus according to the present invention, the predetermined inner conveying path is composed of a sheet discharging conveying path which is discharged from the fixing section and communicates with the sheet stacking section.

In the seventh image forming apparatus according to the present invention, a predetermined feeding start of the recording medium pre-fed at the predetermined position is started from the upstream side of the transfer section through the return conveyance path leading to the paper feed stacking section. Return feeding means for feeding back to the position, time measuring means for measuring a predetermined stop time of the recording medium pre-fed to the predetermined position, and determining whether or not the time measuring means measures the predetermined stop time And a control means for controlling the drive of the return feeding means.

An eighth image forming apparatus according to the present invention is an image forming apparatus having a fixing means for transferring and fixing an image on a first surface or a second surface of a recording medium to be fed and a feeding / conveying path. A temperature detecting means for detecting the temperature of the fixing means, a judging means for judging whether or not the recording medium to be fed is an image recording for the first side, and a fixing means for supplying the fixing means based on the judgment result by the judging means. Second recording medium sent
And a control means for controlling the fixing temperature of the fixing means so that the image fixing temperature for the surface becomes different from the image fixing temperature for the first surface.

A ninth image forming apparatus according to the present invention is an image forming apparatus having a fixing means for transferring and fixing an image on a first surface or a second surface of a recording medium to be fed and a feeding / conveying path. A temperature detecting means for detecting the temperature of the fixing means, a judging means for judging whether or not the recording medium to be fed is an image recording for the first side, and a fixing means for supplying the fixing means based on the judgment result by the judging means. Second recording medium sent
And a control unit for controlling the fixing temperature of the fixing unit so that the second image fixing temperature for the first surface is lower than the first image fixing temperature for the first surface.

The tenth image forming apparatus according to the present invention is provided with a time measuring means for measuring the elapsed time after the second image fixing temperature is set to the fixing means, and the control means controls the predetermined time by the time measuring means. The second image fixing temperature set in the fixing unit is returned to the first image fixing temperature based on the timekeeping state.

In the eleventh image forming apparatus according to the present invention, the fixing means is a fixing roller unit composed of a fixing roller, a heater for heating the fixing roller to a predetermined temperature, and a pressure roller.

In the twelfth image forming apparatus according to the present invention, the fixing means is a fixing unit composed of a fixing film, a ceramic heater for heating the fixing film to a predetermined temperature, and a pressure roller.

According to a thirteenth aspect of the present invention, there is provided a recording medium supply method for an image forming apparatus, which comprises a timing step of timing a stop time of the recording medium pre-fed to the predetermined position with a timing means, and the vicinity of the fed recording medium. A temperature detecting step of detecting the temperature of the temperature by the temperature detecting means, a setting step of variably setting a predetermined stop time measured by the time measuring means based on the detected temperature, and the time measuring means setting the predetermined stop time. A returning step of determining whether or not the time has been counted and starting driving of the returning and feeding means.

[0032]

According to the first aspect of the invention, the recording medium, which has been pre-fed at the predetermined position and then passed through the fixing means without the return feeding means recording an image, is predetermined through a predetermined inner conveying path. The recording medium that has been fed back to the feeding start position can be used as a recording medium for the next image recording without discarding the previously fed recording medium.

According to the second aspect of the invention, after the sheet is pre-fed at the predetermined position, the judgment is made from the timekeeping state by the timekeeping means for measuring the predetermined permissible time until the image recording is canceled without receiving the image recording permission from the data source. The means determines whether or not the previously fed recording medium can be returned and fed, and the control means controls the drive of the backward feeding means based on the determination result to discard the previously fed recording medium. Instead, it can be used as a recording medium for recording the next image without any trouble.

In the third invention, the setting means variably sets the predetermined stop time measured by the time measuring means based on the temperature detected by the temperature detecting means, and the control means sets the predetermined stop time. It is determined whether or not the time measuring unit has timed, the drive of the return feeding unit is controlled, and the pre-fed recording medium is not discarded, but is affected by environmental conditions as a recording medium for the next image recording. It can be used without any hindrance.

In the fourth aspect of the invention, after the sheet is pre-fed at a predetermined position, the recording medium that has passed through the fixing means without being image-recorded by the return feeding means is passed from the fixing section to the intermediate tray. The recording medium is returned and fed to a predetermined feeding start position via the transporting path, and the recording medium fed previously can be used as a recording medium for the next image recording without discarding.

According to the fifth aspect of the invention, the recording medium which has passed through the fixing means without being image-recorded by the returning and feeding means after being pre-fed at a predetermined position is fed from the downstream side of the fixing section to the upstream side of the sheet feeding. The recording medium is returned and fed to a predetermined feeding start position via a return conveying path leading to the recording medium and can be used as a recording medium for the next image recording without discarding the previously fed recording medium.

According to the sixth aspect of the invention, after the sheet is pre-fed at a predetermined position, the recording medium that has passed through the fixing unit without the return feeding unit recording an image is discharged from the fixing unit and is stacked. The recording medium is returned to a predetermined feeding start position through a sheet discharging and conveying path leading to the sheet and fed, and the previously fed recording medium can be used as a recording medium for the next image recording without discarding.

In the seventh aspect of the invention, the control means determines whether or not the time measuring means for measuring a predetermined stop time of the recording medium pre-fed to the predetermined position measures the predetermined stop time, and the predetermined position is determined. The pre-feeding recording medium is controlled from the upstream side of the transfer section to the predetermined feeding start position via the return conveyance path leading to the sheet feeding and stacking section to control the drive of the return feeding means, It is possible to use the fed recording medium as a recording medium for the next image recording without any trouble without discarding it.

In the eighth invention, the control means of the recording medium fed to the fixing means is based on the judgment result by the judging means for judging whether the fed recording medium is the image recording of the first side. Set the image fixing temperature for the second side to the first
The fixing temperature of the fixing unit detected by the temperature detecting unit is controlled so that the image fixing temperature of the first surface becomes different from that of the first surface, and the power consumption of the fixing unit during the image fixing process of the first surface and the second surface is reduced. It can be controlled.

In the ninth invention, the control means of the recording medium to be fed to the fixing means is based on the judgment result by the judging means for judging whether the fed recording medium is the image recording of the first side. The fixing temperature of the fixing means detected by the temperature detecting means is controlled so that the second image fixing temperature for the second surface becomes lower than the first image fixing temperature for the first surface, and the first surface and the second surface are controlled. It is possible to reduce the power consumption of the fixing unit during the image fixing process.

In the tenth aspect of the invention, the control means sets the fixing means on the basis of the timed state of a predetermined time by the timekeeping means for counting the elapsed time after the second image fixing temperature is set for the fixing means. The second image fixing temperature, which has been set, is returned to the first image fixing temperature, and after the image fixing temperature of the second surface is set, stable image fixing can be performed even when a state in which no image is recorded continues for a while.

In the eleventh aspect of the invention, the control means of the recording medium fed to the fixing means is based on the judgment result by the judging means for judging whether the fed recording medium is the image recording of the first side. A fixing roller including a fixing roller, a heater for heating the fixing roller to a predetermined temperature so that the second image fixing temperature for the second surface is lower than the first image fixing temperature for the first surface, and a pressure roller. The fixing temperature of the unit is controlled based on the output of the temperature detecting means, and the first
The power consumption of the fixing roller unit including the heater for heating the fixing roller during the image fixing process for the first and second surfaces is reduced.

In the twelfth aspect of the invention, the control means of the recording medium to be fed to the fixing means is based on the judgment result by the judging means for judging whether the fed recording medium is the image recording of the first side. A fixing film including a fixing film, a ceramic heater for heating the fixing film to a predetermined temperature, and a pressure roller so that the second image fixing temperature for the second surface is lower than the first image fixing temperature for the first surface. The fixing temperature of the unit is controlled based on the output of the temperature detecting means, and from the fixing film at the time of the image fixing processing of the first surface and the second surface, the ceramic heater for heating the fixing film to a predetermined temperature, and the pressure roller. The power consumption of the fixing unit is significantly reduced.

In the thirteenth invention, the stop time of the recording medium pre-fed to the predetermined position is timed by the time measuring means, and the temperature in the vicinity of the fed recording medium is detected by the temperature detecting means.
Based on the detected temperature, the predetermined stop time measured by the time measuring means is variably set, and it is determined whether or not the time measuring means has measured the set predetermined stop time, and the return feeding means is driven. It is possible to use the previously fed recording medium as a recording medium for the next image recording without any trouble without discarding it.

[0045]

【Example】

[First Embodiment] FIG. 1 is a schematic sectional view illustrating the configuration of an image forming apparatus according to a first embodiment of the present invention.

In the figure, 1 is a main body, 2 is a cassette,
The recording paper S is accommodated and is fed by the paper feed roller 5 in the arrangement direction of the registration roller 100. 4 is a bypass tray,
The manual paper feed roller 8 feeds the manual paper in the direction in which the registration rollers 100 are arranged. A paper feed sensor 6 is composed of, for example, an optical sensor or a micro switch. A pre-registration sensor (registration sensor) 7 detects the presence / absence of pre-fed recording paper and outputs a paper presence / absence signal to the input INT2 of the printer control circuit 24. Reference numeral 17 denotes a photosensitive drum, which emits a laser beam modulated based on an image signal emitted from the laser unit 13 to a polygon motor 22.
It is deflected by a polygon mirror driven by and is further returned to the photosensitive drum 17 via the scanning mirror 16 to form an electrostatic latent image.

Numeral 19 is a charger composed of a charging roller,
The photosensitive drum 17 is uniformly charged before forming a latent image. 21
Is a transfer roller that functions as a contact charger, and is a developing device 20.
The toner image developed by is transferred onto a recording paper.

A fixing device 14 has a fixing roller and permanently fixes the toner image transferred on the recording paper. 1
Reference numeral 1 denotes a paper discharge roller, which feeds the recording paper, which has been thermally fixed, in the paper discharge direction or the return path RT direction. Reference numeral 25 is a flapper, which is disposed on the upper side or the lower side in the drawing by a solenoid 68 which is driven based on a direction control signal from the output OUT2 of the MPU 24d. Determine the feeding direction of recording paper or pre-feed paper. Reference numeral 12 denotes a paper discharge tray on which recording paper on which image formation has been completed is stacked. Reference numeral 8 is a paper feed roller, 10 is a paper discharge sensor, 28 is a conveyance roller, and 29 is a sensor.

Reference numeral 61 is a temperature sensor, which is the printer control circuit 2
It is arranged at a predetermined position on the control board including 4 and outputs the detected in-machine temperature signal to the A / D input of the MPU 24d.

FIG. 2 is a circuit diagram illustrating the control configuration of the image forming apparatus shown in FIG.

In the figure, 24d is the printer control circuit 2.
The MPU provided in the unit 4 collectively controls the operation of each unit based on the control program stored in the ROM 24a. The MPU 24d includes a RAM 24b, a timer 24c, an A / D converter and the like. However, A / D
Even an MPU that configures a converter as an external device,
It does not prevent the application of the present invention.

Reference numeral 14 is a fixing device, and the halogen heater 14c therein is a solid state relay (SS) described later.
R) 53 is connected to a commercial power source (AC power source) via a triac 53a. The SSR 53 is composed of a triac 53a, an LED 53b, a zero-cross detection circuit (not shown), etc. When the LED 53b emits light, the triac 53a becomes conductive and the halogen heater 14c is turned on.

The LED 53b has a resistor 60 on the anode side.
Connected to a DC power supply (power supply for operating the printer control circuit 24 (created from a commercial power supply by a low-voltage power supply circuit (not shown)), and the cathode side is connected to the collector of an emitter-grounded NPN transistor 57. Has been done. The base of the transistor 57 is connected to the output port of the MPU 24d via the resistor 59 and the resistor 58 which are grounded.

Therefore, the MPU 24d sets the output port to L
When set to (OFF), the LED 53b does not turn on, so the halogen heater 14c does not turn on. When the output port is set to H (ON), the LED 53b turns on and the halogen heater 14c turns on.

On the other hand, the temperature detecting element functioning as the temperature detecting means in the fixing device 14, preferably the thermistor 14d, has one end connected to the DC power source and the other end connected to the resistor 5
Connected to 5.

The analog voltage Vt determined by the values of the thermistor 14d and the resistor 55 is A / D of the MPU 24d.
It is input to the conversion input port, and the MPU 24d detects the fixing device temperature.

In the above structure, the MPU 24d monitors the temperature of the fixing device by the analog voltage Vt, and controls the temperature of the fixing device 14 by changing the ON / OFF duty of the output port.

Reference numeral 61 is a temperature detecting element, preferably a thermistor, which functions as a temperature detecting means for measuring the temperature inside the machine.
It is provided on the printer control circuit 24. 62 is a resistor. The voltage divided by the thermistor 61 and the resistor 62 is input to the A / D input of the MPU 24d. MPU24d
Outputs OUT2, OUT3, OUT4, OUT5 of
Load driving transistors 64, 67, 70 and 73 are connected through resistors 63, 66, 69 and 72, respectively, as shown in the drawing, and the resist clutch 65 and flapper 25 are connected.
Drive solenoid 68, clutch 7 of the transport roller 28
1, the clutch 74 of the paper feed roller 5 is driven.

The pre-feed signal is applied to the terminal 75 of the input IN1 of the MPU 24d, the sensor signal from the pre-registration sensor 7 is applied to the terminal 76 of the input IN2, and the print signal is applied to the terminal 77 of the input IN3.

Hereinafter, the first to third, fifth and eighth aspects of the present invention will be described.
Correspondence between the twelfth image forming apparatus and the first embodiment and the operation thereof will be described.

In the first image forming apparatus, after the sheet is pre-fed at a predetermined position (position detected by the registration sensor 7), the fixing means (fixing device 14 (fixing roller, fixing roller,
A re-feeding unit (re-feeding unit) that re-feeds the recording medium, which has passed through a fixing roller unit including a heater and a pressure roller, to a predetermined feeding start position via a predetermined inner conveying path (return path RT). The recording medium, which has a conveying roller 28 and a conveying roller (not shown), has passed through the fixing device 14 without being image-recorded after being pre-fed at a predetermined position through a return path RT. The recording medium is returned to the feeding start position (position detected by the sensor 29) and is used as a recording medium for the next image recording without discarding the previously fed recording medium.

In the second image forming apparatus, after the paper is pre-fed at a predetermined position (position detected by the registration sensor 7), the fixing means (fixing device 14 (fixing roller, fixing roller,
A re-feeding unit (re-feeding unit) that re-feeds the recording medium, which has passed through a fixing roller unit including a heater and a pressure roller, to a predetermined feeding start position via a predetermined inner conveying path (return path RT). A transport roller 28 and a transport roller (not shown), and a timing for counting a predetermined permissible time until the image recording is canceled without receiving the image recording permission from the data source after being pre-fed at the predetermined position. Means (timer 24c), judging means (MPU 24d) for judging whether or not the previously fed recording medium can be fed back and fed from the timed state by the timing means, and the feeding back is made on the basis of the judgment result of this judging means. Control means for controlling the drive of the sending means (MP
U24d), the MPU 24d pre-feeds from a time counting state by a timer 24c that measures a predetermined allowable time until the image recording is canceled without receiving the image recording permission from the data source after being pre-fed at a predetermined position. Whether or not the recording medium that has been printed can be returned and fed is determined, and based on the result of the determination, the driving of the returning and feeding means including the feeding roller 28 and a feeding roller (not shown) is controlled to advance feeding. The recording medium can be used as a recording medium for the next image recording without any trouble without discarding the recording medium.

In the third image forming apparatus, the recording medium pre-fed at the predetermined position (position detected by the registration sensor 7) is moved to the predetermined feeding start position via the inner transport path (return path RT). Return-feeding means for returning and feeding (composed of a transport roller 28 and a transport roller (not shown)), and a clocking means (timer 24c) for timing a predetermined stop time of the recording medium pre-fed to the predetermined position. Temperature detecting means (thermistor 61) for detecting the temperature in the vicinity of the fed recording medium,
Based on the temperature detected by the temperature detecting means, a predetermined stop time measured by the time measuring means is variably set (MPU2).
4d) and the control means (MPU24) for controlling the drive of the return feeding means by determining whether or not the timing means has timed the predetermined stop time set by the setting means.
d) and, based on the temperature detected by the thermistor 61, the MPU 24d variably sets a predetermined stop time measured by the timer 24c, and whether the MPU 24d measures the predetermined stop time set by the timer 24c. Is judged,
By controlling the drive of the returning and feeding means, the previously fed recording medium can be used as a recording medium for the next image recording without being affected by environmental conditions without discarding the recording medium.

In the fifth image forming apparatus, as shown in FIG. 1, the predetermined inner conveyance path is constituted by a return conveyance path (return passage RT) which extends from the downstream side of the fixing section to the upstream side of the sheet feeding. is there.

The eighth image forming apparatus is an image forming apparatus having a fixing means for transferring and fixing an image on a first surface or a second surface of a recording medium to be fed and a feeding / conveying path. Temperature detecting means (thermistor 14d) for detecting the temperature of the recording medium, and determining means (MPU 24d) for determining whether or not the recording medium fed is the image recording of the first side.
And the fixing means fixes the image fixing temperature for the second surface of the recording medium fed to the fixing means to a temperature different from the image fixing temperature for the first surface based on the determination result by the determining means. Control means for controlling temperature (MPU
24d) and the image fixing temperature for the second side of the recording medium fed to the fixing device 14 based on the determination result by the MPU 24d that determines whether the fed recording medium is the image recording for the first side. The fixing temperature of the fixing device 14 detected by the thermistor 14d is controlled so that the image fixing temperature of the first surface is different from the image fixing temperature of the first surface.
It is possible to control the power consumption of the fixing device 14 at the time of the image fixing process with the surface.

The ninth image forming apparatus is an image forming apparatus having a fixing means for transferring and fixing an image on a first surface or a second surface of a recording medium to be fed and a feeding / conveying path. A temperature detecting means (thermistor 14d) for detecting the temperature of the (fixing device 14) and whether or not the recording medium to be fed is image recording for the first side (MPU24)
d) and the second image fixing temperature for the second surface of the recording medium fed to the fixing means is set to be lower than the first image fixing temperature for the first surface based on the determination result by the determining means. The fixing unit 14 has a control unit (MPU 24d) for controlling the fixing temperature of the fixing unit, and is fed to the fixing unit 14 based on the determination result by the MPU 24d that determines whether the fed recording medium is the image recording of the first side. The fixing temperature of the fixing means detected by the thermistor 14d is controlled so that the second image fixing temperature for the second surface of the recording medium becomes lower than the first image fixing temperature for the first surface. It is possible to reduce the power consumption of the fixing unit during the image fixing processing for the first and second surfaces.

The tenth image forming apparatus is provided with a timer (timer 24c) for measuring the elapsed time after the second image fixing temperature is set to the fixing means (fixing device 14), and the control means (MPU 24d) is provided. A state in which the second image fixing temperature set in the fixing device 14 is returned to the first image fixing temperature based on the timed state of the timer 24d and the image is not recorded for a while after the image fixing temperature of the second side is set. It is possible to perform stable image fixing even when is continued.

In the eleventh image forming apparatus, the fixing means (fixing device 14) is constituted as a fixing roller unit comprising a fixing roller, a heater 14c for heating the fixing roller to a predetermined temperature, and a pressure roller. Then, the controller fixes the second image to the second surface of the recording medium fed to the fixing unit based on the determination result by the determination unit that determines whether the fed recording medium is the image recording of the first side. The temperature detecting means detects the fixing temperature of a fixing roller unit including a fixing roller, a heater for heating the fixing roller to a predetermined temperature, and a pressure roller so that the temperature becomes lower than the first image fixing temperature of the first surface. Control based on the output of
The power consumption of the fixing roller unit including the heater for heating the fixing roller during the image fixing process for the first and second surfaces is reduced.

In the twelfth image forming apparatus, the fixing means (fixing device 14) is a fixing unit composed of a fixing film (not shown), a ceramic heater for heating the fixing film to a predetermined temperature, and a pressure roller. The low temperature melting type toner transferred to the recording medium is fixed by the fixing film by the on-demand fixing method.
The control unit determines the second image fixing temperature for the second face of the recording medium fed to the fixing unit based on the determination result by the determining unit that determines whether the fed recording medium is the image recording of the first face. The fixing temperature of the fixing unit including a fixing film, a ceramic heater that heats the fixing film to a predetermined temperature, and a pressure roller so that the temperature is lower than the first image fixing temperature of the first surface is output from the temperature detecting means. Power consumption of the fixing unit composed of a fixing film, a ceramic heater for heating the fixing film to a predetermined temperature, and a pressure roller at the time of image fixing processing on the first and second surfaces is significantly controlled. It will save you money.

FIG. 3 is a flow chart showing a recording medium feeding method of the image forming apparatus showing the first embodiment of the present invention.
Note that (1) to (15) indicate each step. Further, each step is executed by the MPU 24d shown in FIG.

In step (1), the MPU 2 shown in FIG.
When the pre-feed signal input to the input IN1 of the 4d is received, in step (2), the output OUT5 of the MPU 24d shown in FIG. 2 outputs an output to drive the transistor 73 to operate the paper feed clutch 74 to cause the paper feed roller 5 to move. It rotates to start feeding.

In step (3), the process waits until the paper reaches the pre-registration sensor 7 and the sensor signal is input to IN2. When the paper reaches the registration sensor 7 in step (4), the output OUT5 is turned off so as to stop the paper feed roller 5.

In step (5), the voltage of the thermistor 61 for the in-machine temperature sensor is fetched from the A / D input 2, and in step (6), the time limit tL is calculated from the detected temperature T by the following equation to the following equation (1). Calculate based on

T _L = ta −b · (T−Ta) (1) where ta is the standard machine temperature Ta (for example, 25 ° C.)
Is the time limit. As the temperature T inside the machine rises,
If the hardness of the paper decreases and it stays, it becomes easy to deform. The degree is 50 when the residence time at 25 ° C is 5 minutes.
It decreases to about 1/5 at ° C. Therefore, the coefficient of b in the above formula (1) is determined.

[0075] Next, to start the timer 24c in the MPU24d in step (7), timer 24c in step (8), it is checked whether or not the timer value t is within the time limit tL for counting, there within the time limit t _L For example, in step (9), check if the print signal has come, and the print signal
If it is input to the input IN3 of d, the process proceeds to step (10) for printing. If no print signal is received, the process returns to step (8).

On the other hand, in the determination of step (8), the timer 2
When the timer value t counted by 4c exceeds the time limit t _L , the output OUT2 outputs an output to the registration clutch 65 to turn on the registration roller in step (11). Then, in step (12), the flapper 25
MPU2 to move the motor in the return direction (downward in the figure)
It is output from the output OUT3 of 4d.

Next, in step (13), the transport roller 28
MPU24d to energize the latch 71 for moving
The output OUT4 of is turned on.

Next, at step (14), the return path RT
The sensor 29 waits for the paper to come back through. When the paper reaches the sensor 29, the output OUT4 of the MPU 24d is turned off so as to stop the transport roller 28 in step (15).

When the recording paper pre-fed as described above is not printed within the time limit defined as a variable time according to the temperature inside the apparatus and the state is continued, the recording paper may be returned through the return path. it can.

As described above, in the recording medium feeding method of the image forming apparatus according to the present invention, the time measuring step (step (7)) of measuring the stop time of the recording medium pre-fed to the predetermined position by the time measuring means.
And a temperature detecting step (step (5)) of detecting the temperature near the fed recording medium by the temperature detecting means, and a setting for variably setting a predetermined stop time measured by the time measuring means based on the detected temperature. Step (step (6)) and returning step (step (8), step (8), which determines whether or not the time measuring means has timed the set predetermined stop time and starts driving the return feeding means. 11) to (15)), the stop time of the recording medium pre-fed to a predetermined position is counted by the timer 24c, and the temperature near the fed recording medium is detected by the thermistor 61. The predetermined stop time measured by the timer 24c is variably set based on the detected temperature, and it is determined whether or not the timer 24c has measured the set predetermined stop time, and the return feeding means (conveyance roller 28 And not shown And starts to drive the conveying roller and the like), those which can be used without any problem as a next image recording operation of the recording medium without discarding the previous feeding printing media. [Second Embodiment] FIG. 4 is a sectional view for explaining the schematic arrangement of an image forming apparatus according to the second embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals.

Here, the temperature sensor 61 composed of a thermistor is placed near the registration roller 100.

As a result, the environmental temperature of the fed recording paper (cassette fed recording paper and manually fed recording paper) can be measured more accurately. [Third Embodiment] FIG. 5 is a flowchart showing a first fixing temperature control method for an image forming apparatus according to the third embodiment of the present invention. Note that (1) to (13) indicate each step.
Further, each step is executed by the MPU 24d shown in FIG.

First, when the power is turned on (start),
Turn on the halogen heater 14c (1), and then the thermistor 14
It is determined whether the heat roller temperature T _H detected from d is equal to or higher than the predetermined standby temperature T _S (2). If the temperature is equal to or lower than the predetermined standby temperature T _S , the process returns to step (1) to turn on the halogen heater 14c. To do. Step (1) ~
The step (2) is called a warm-up state.

When the heat roller temperature T _H reaches the predetermined standby temperature T _S , it is judged whether or not the heat roller temperature T _H is higher than the standby temperature T _S (3). If the temperature is higher than the standby temperature T _{S, the} halogen heater is turned off. (4) If not, the halogen heater 14c is turned on (5).
Then, it is judged whether or not there is a print instruction (instructed via the input INT2) from the external device (6), and if there is no print instruction, the process returns to step (3).

In this embodiment, the steps (3) to (6) are referred to as a standby state. Further, in the standby state, the temperature of the heat roller 14a is adjusted to the temperature T _S in the standby state.

If it is determined in step (6) that there is a print instruction, the print instruction from the external device is the first instruction.
It is judged whether or not it is the surface printing (7), and if it is the first surface printing, it is judged whether the heat roller temperature _TH is the first surface printing temperature _Tp1 or higher (8), and if the first surface printing temperature _Tp1 or higher. The halogen heater 14c is turned off (9), otherwise, the halogen heater is turned on (10) and the process returns to (6).

[0087] On the other hand, in the judgment of step (7), if the first surface print, the heat roller temperature T _H is determined whether or not the second face print temperature T _p2 or (11), the halogen heater if T _p2 more 14c is turned off (12), otherwise, the halogen heater 14c is turned on (13), and the process returns to step (6).

According to this embodiment, the fixing temperature at the time of recording on the second side is lower than that at the time of recording on the first side, and the fixing is performed at the minimum necessary temperature. As a result, the power consumption of the halogen heater 14c at the time of recording on the second surface is the power consumption for the sufficient fixing process at the temperature of the heat roller T _H being the first surface printing temperature T _p1 or less, which is a waste of power. Can be suppressed. [Fourth Embodiment] Next, a fourth embodiment of the present invention will be described.

The apparatus configuration of the fourth embodiment is almost the same as that shown in FIGS. 1 and 4 of the third embodiment.

The difference between the third embodiment and the fourth embodiment is that
When a predetermined time elapses after the recording sheet S is temporarily stopped at the re-feeding port and before a command from the host computer is sent, recording is performed at the same fixing unit temperature during the second side recording as during the second side recording. Is what is done.

FIG. 6 is a flow chart showing a second fixing temperature control method of the image forming apparatus showing the fourth embodiment of the present invention. Note that (1) to (14) indicate each step. Further, each step is executed by the MPU 24d shown in FIG.

In the fourth embodiment, in addition to the processing according to the flowchart of FIG. 5 corresponding to the third embodiment, step (1
In 4), that is, when it is determined in step (7) that the printing is the second side printing (not the first side printing), it is determined whether or not the time set for switching the fixing temperature is over.

If it is determined in step (14) that the fixing temperature switching time has expired, the process proceeds to step (8). If not, the process proceeds to step (11). I do.

The judgment value for judging whether or not the fixing temperature switching time has expired is stored in the RAM 24b. Hereinafter, details of the fixing temperature switching time-over processing (fixing temperature switching time-over processing when paper is fed to the re-feed port) will be described with reference to the flowchart shown in FIG.

FIG. 7 is a flow chart showing an example of a fixing temperature switching time-over processing procedure in the second fixing temperature control method of the image forming apparatus showing the fourth embodiment of the present invention. Note that (1) to (5) indicate each step.

First, when the paper is fed to the re-feed port, FIG.
The timer 24c shown in (1) is started (1), then it is judged whether or not the command for the second side print is sent from the external device (2), and if it is sent, the timer timing processing of the timer 24c is performed. Stop (5) and end the process.

On the other hand, in step (2), if the command for printing the second side has not been sent yet, it is judged whether the time T from the start of the timer 24c is a predetermined time T0 or more (3), Otherwise, the process returns to (2), and if it is equal to or longer than the predetermined time T0, the flag indicating the fixing temperature switching time-out is stored in the RAM 24b (4), the time counting process by the timer 24c is stopped (5), and the process ends.

Therefore, when the recording paper is left at the re-feeding port for a predetermined time, the state of the first surface and the paper are almost the same.
Even when recording on the second side, the toner image can be reliably fixed on the recording paper at the same temperature as when recording on the first side.

Although the heat fixing device using the heat roller (fixing device 14 shown in FIG. 1) has been described in the above embodiment, the present invention is not limited to the heat roller fixing device. A fixedly supported heating element (hereinafter referred to as "Kaisho 63-313182")
A heater (referred to as a ceramic heater, for example), a heat-resistant film that is conveyed (moved and driven) while being in pressure contact with the heater, and a pressurizing member that adheres a recording material to the heater via the film, By applying the heat of the above to the recording material through the film, the unfixed image formed and carried on the recording material surface is heated and fixed on the recording material surface (on-demand fixing method). Can be applied. In particular, in the case of the on-demand fixing method, the melting temperature of the toner is about 10% lower than the melting temperature of the toner used in the heat roller method. Therefore, by performing the fixing control, the power saving effect is further enhanced. Become. [Fifth Embodiment] FIG. 8 is a schematic sectional view for explaining the structure of an image forming apparatus according to the fifth embodiment of the present invention, for example, for a laser beam printer. The configuration and operation will be described below.

The main body 1 is a cassette 2 for storing the recording paper S.
A sheet feeding roller 5 for feeding the recording sheet S from the cassette 2 is provided. Further, downstream of the paper feed roller 5, a paper feed sensor 6 for monitoring the state of paper conveyance and a registration sensor 7 are arranged. Apart from the above-mentioned transport route,
A paper feed roller 8 for feeding paper from the manual feed tray 4 is provided.

Downstream, there are a photosensitive drum 17, a charging device 19, a developing device 20, and a transfer roller 21 which are necessary for a known electrophotographic process. A laser unit 13 for exposing the photosensitive drum 17 to light, a polygon motor 22 for scanning the laser, and a scanning mirror 16 are provided.

A fixing device 14 for thermally fixing the toner image formed on the recording paper S is arranged. Further downstream, a paper ejection sensor 10 for detecting the paper conveyance state of the paper ejection unit, and the recording paper S.
A paper discharge roller 11 for discharging the paper and a paper discharge tray 12 for stacking the recording paper S for which recording has been completed are arranged.

A return flapper 25 for switching the path for returning the paper into the cassette 2 and the normal path is provided downstream of the paper discharge roller 11, and a vertical switching flapper for switching the upper and lower stages of the cassette is provided on the path for returning the paper into the cassette. There are 26.

When the printer control circuit 24 determines that there is no printing on the paper, it turns on the return flapper 25 and returns the paper to the paper feed section. Correspondence between the sixth image forming apparatus according to the present invention and the fifth embodiment will be described below.

In the sixth image forming apparatus, as shown in FIG. 8, a predetermined inner conveying path is a sheet discharging conveying path where sheets are discharged from the fixing section and lead to the sheet feeding stacking section (each upper limit cassette 2). RT2
It is composed of.

With this configuration, even if the image forming apparatus does not have the return path RT, each flapper 2
5, the recording paper S pre-fed to the position of the registration sensor 7 is minimized by the deformation shown in the recording paper S pre-fed according to the procedure shown in the flow chart shown in FIG. It is possible to form an image without image unevenness even if the paper is fed again during the next image formation. [Sixth Embodiment] FIG. 9 is a schematic sectional view illustrating the structure of an image forming apparatus according to the sixth embodiment of the present invention. The same parts as those in FIG. 8 are designated by the same reference numerals.

Compared with the image forming apparatus shown in FIG. 8, a paper path R that does not pass through the transfer section and the fixing section is provided.
It does not change the state of the paper that is reused. In this embodiment, the detour flapper 27 is added as the path switching. Correspondence between the seventh image forming apparatus according to the present invention and the sixth embodiment will be described below.

The seventh image forming apparatus feeds the recording medium pre-fed at the predetermined position through a return conveyance path (paper path R) from the upstream side of the transfer section to the paper feed stacking section. Returning and feeding means (constituted by a conveyance roller (not shown)) for feeding back to the starting position and timing means (timer 2) for measuring a predetermined stop time of the recording medium pre-fed to the predetermined position.
4c) and control means (MPU 24d) for controlling the drive of the return feeding means by judging whether or not the timekeeping means has timed the predetermined stop time, and at a predetermined position (by the registration sensor 7). The recording medium pre-fed to the predetermined position is determined by the MPU 24d whether or not the timer 24c, which measures the predetermined stop time of the recording medium pre-fed to the detected position), has measured the predetermined stop time. By controlling the drive of the return feeding means for feeding back the sheet from the upstream side of the transfer portion to the predetermined feeding start position via the paper path R leading to the paper feed stacking portion,
The previously fed recording medium can be used as a recording medium for the next image recording without any trouble without discarding.

With this configuration, even if the image forming apparatus does not have the return path RT, each flapper 2
5, the recording paper S pre-fed to the position of the registration sensor 7 is minimized by the deformation shown in the recording paper S pre-fed according to the procedure shown in the flow chart shown in FIG. Even if the paper is fed again during the next image formation, an image without image unevenness can be formed, and the paper path R for bypassing prevents the drum system and the fixing roller system from applying pressure. Since the recording sheet S pre-fed to the cassette 2 can be returned, the recording sheet S is remarkably less deformed and can be reused as a recording sheet suitable for good image formation. [Seventh Embodiment] FIG. 10 is a schematic sectional view illustrating the structure of an image forming apparatus according to the seventh embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals.

In this embodiment, as compared with the first embodiment, re-feeding is performed by utilizing the double-sided printing reversal path originally having the re-feeding path RT1. As a means for this, a double-sided / reuse switching flapper 30 and a reversing flapper 31 are provided. Hereinafter, the fourth image forming apparatus according to the present invention and the seventh
The correspondence with the embodiment will be described.

In the fourth image forming apparatus, as shown in FIG. 10, the predetermined inner conveying path is composed of a double-sided / multiplexing conveying path (refeeding path RT1) leading from the fixing section to the intermediate tray. is there. [Eighth Embodiment] FIG. 11 is a timing chart for explaining the first print cancel extension sequence of the image forming apparatus according to the eighth embodiment of the present invention.

As shown in the figure, normally, the print cancellation after the image synchronization timing is controlled as not permitted, but by causing the MPU 24d of the printer control circuit 24 to function as the image writing stop means, By controlling the laser drive system to output a signal for prohibiting image writing when the waiting time set on the recording sheet S has elapsed, the print cancel timing can be permitted up to the image writing start timing. Becomes [Ninth Embodiment] FIG. 12 is a timing chart for explaining the second print cancel extension sequence of the image forming apparatus showing the ninth embodiment of the present invention.

As shown in this figure, when the waiting time set for the pre-fed recording paper S has elapsed, a signal for prohibiting image writing is output to the laser drive system and high voltage drive of the transfer charger is performed. By controlling the application timing, it becomes possible to permit the print cancel timing to the transfer start timing on the recording paper S, which is further delayed from the image writing start timing.

[0114]

As described above, the first aspect of the present invention
According to this image forming apparatus, the recording medium that has passed through the fixing unit without being subjected to image recording by the return feeding unit after being pre-fed at the predetermined position is fed by a predetermined feeding path. The recording medium fed back to the feeding start position can be used as the recording medium for the next image recording without discarding the previously fed recording medium.

According to the second image forming apparatus, the time is measured by the time measuring means for measuring the predetermined permissible time until the image recording is canceled without receiving the image recording permission from the data source after the sheet is pre-fed at the predetermined position. From the state, the determination means determines whether or not the previously fed recording medium can be returned and fed, and the control means controls the drive of the previously fed recording medium based on the result of the determination, and the previously fed recording medium. Can be used as a recording medium for the next image recording without any trouble without discarding.

According to the third image forming apparatus, the setting means variably sets the predetermined stop time measured by the time measuring means based on the temperature detected by the temperature detecting means, and the control means sets the predetermined stop time. It is determined whether or not the time measuring means measures the stop time, and the drive of the returning and feeding means is controlled,
The pre-fed recording medium can be used as a recording medium for the next image recording without discarding without being affected by environmental conditions without discarding.

According to the fourth image forming apparatus, after the paper is pre-fed to the predetermined position, the recording medium which has passed through the fixing means without being recorded by the return feeding means is passed from the fixing section to the intermediate tray. The recording medium is returned to a predetermined feeding start position through the double-sided / multiplexing conveyance path and is fed, and the recording medium fed previously can be used as a recording medium for the next image recording without discarding.

According to the fifth image forming apparatus, after the sheet is pre-fed at the predetermined position, the recording medium which has passed through the fixing unit without being recorded by the return feeding unit is fed from the downstream side of the fixing unit. The recording medium fed back to the predetermined feeding start position via the return conveyance path leading to the upstream side of the paper can be used as a recording medium for the next image recording without discarding.

According to the sixth image forming apparatus, after the paper is pre-fed at a predetermined position, the recording medium which has passed through the fixing means without being recorded by the return feeding means is discharged from the fixing section. It is possible to return the sheet to a predetermined sheet feeding start position through the sheet discharging and conveying path leading to the sheet feeding and stacking section, and feed the sheet, so that the previously fed sheet can be used as a sheet for recording the next image without discarding the sheet.

According to the seventh image forming apparatus, the control means determines whether or not the time measuring means for measuring the predetermined stop time of the recording medium previously fed to the predetermined position measures the predetermined stop time. Controls the drive of the return feeding unit that returns and feeds the recording medium pre-fed at a predetermined position to the predetermined feeding start position from the upstream side of the transfer unit through the return conveyance path that leads to the paper feeding stacking unit. Thus, the previously fed recording medium can be used as a recording medium for the next image recording without any trouble without discarding.

According to the eighth image forming apparatus, the control means is fed to the fixing means on the basis of the judgment result by the judgment means for judging whether the fed recording medium is the image recording for the first side. The fixing temperature of the fixing means detected by the temperature detecting means is controlled so that the image fixing temperature for the second surface of the recording medium is different from the image fixing temperature for the first surface, and the first surface and the second surface are controlled. It is possible to control the power consumption of the fixing unit during the image fixing process.

According to the ninth image forming apparatus, the control means is fed to the fixing means based on the judgment result by the judgment means for judging whether the fed recording medium is the image recording for the first side. The fixing temperature of the fixing means detected by the temperature detecting means is controlled so that the second image fixing temperature for the second surface of the recording medium becomes lower than the first image fixing temperature for the first surface, and It is possible to reduce the power consumption of the fixing unit during the image fixing process with the second surface.

According to the tenth image forming apparatus, the control means fixes the fixing means on the basis of the timed state of the predetermined time by the timekeeping means for counting the elapsed time after the second image fixing temperature is set for the fixing means. The second image fixing temperature set in the means is restored to the first image fixing temperature, and stable image fixing can be performed even after a state where no image is recorded for a while after the image fixing temperature of the second surface is set.

According to the eleventh aspect, the recording medium is fed to the fixing unit by the control unit based on the determination result by the determination unit that determines whether the fed recording medium is the image recording for the first side. A fixing roller including a fixing roller, a heater for heating the fixing roller to a predetermined temperature, and a pressure roller so that the second image fixing temperature for the second surface becomes lower than the first image fixing temperature for the first surface. Since the fixing temperature of the roller unit is controlled based on the output of the temperature detecting means, it is possible to reduce the power consumption of the fixing roller unit including the heater for heating the fixing roller during the image fixing process of the first surface and the second surface. You can

According to the twelfth aspect of the invention, the recording medium is fed to the fixing means by the control means on the basis of the judgment result by the judging means for judging whether the fed recording medium is the image recording for the first side. A fixing film, a ceramic heater that heats the fixing film to a predetermined temperature, and a pressure roller so that the second image fixing temperature for the second surface of the sheet is lower than the first image fixing temperature of the first surface. Since the fixing temperature of the fixing unit is controlled on the basis of the output of the temperature detecting means, the fixing film at the time of the image fixing process of the first surface and the second surface, the ceramic heater for heating the fixing film to a predetermined temperature, the pressure roller It is possible to remarkably reduce the power consumption of the fixing unit composed of.

According to the recording medium feeding method of the image forming apparatus of the present invention, the stop time of the recording medium pre-fed to the predetermined position is timed by the timing means, and the temperature in the vicinity of the fed recording medium is controlled by the temperature. The temperature detected by the detection means is detected, and the predetermined stop time measured by the time measurement means is variably set based on the detected temperature, and it is determined whether or not the time measurement means has measured the set predetermined stop time. Then, since the driving of the returning and feeding means is started, the recording medium that has been fed previously can be used as a recording medium for the next image recording without any trouble without discarding.

[Brief description of drawings]

FIG. 1 is a schematic sectional view illustrating the configuration of an image forming apparatus showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram illustrating a control configuration of the image forming apparatus illustrated in FIG.

FIG. 3 is a first image forming apparatus showing a first embodiment of the present invention.
5 is a flowchart showing a pre-feed control method of the above.

FIG. 4 is a sectional view illustrating a schematic configuration of an image forming apparatus showing a second embodiment of the present invention.

FIG. 5 is a first image forming apparatus showing a third embodiment of the present invention.
6 is a flowchart showing a fixing temperature control method of No. 1.

FIG. 6 is a second image forming apparatus showing a fourth embodiment of the present invention.
6 is a flowchart showing a fixing temperature control method of No. 1.

FIG. 7 is a second image forming apparatus showing a fourth embodiment of the present invention.
6 is a flowchart showing an example of a fixing temperature switching time-over processing procedure in the fixing temperature control method of FIG.

FIG. 8 is a schematic sectional view illustrating a configuration of an image forming apparatus showing a fifth embodiment of the present invention.

FIG. 9 is a schematic sectional view illustrating the configuration of an image forming apparatus showing a sixth embodiment of the present invention.

FIG. 10 is a schematic sectional view illustrating the configuration of an image forming apparatus showing a seventh embodiment of the present invention.

FIG. 11 is a timing chart illustrating a first print cancel extension sequence of the image forming apparatus according to the eighth embodiment of the present invention.

FIG. 12 is a timing chart illustrating a second print cancel extension sequence of the image forming apparatus according to the ninth embodiment of the present invention.

[Explanation of symbols]

 RT return path 7 registration sensor 14 fixing device 24 printer control circuit 28 transport roller 100 registration roller

Claims (13)

[Claims] 1. An image forming apparatus that has a fixing unit that heats and presses a recording medium to fix an image, and pre-feeds the recording medium to a predetermined position before writing an image. After that, there is provided return feeding means for returning the recording medium, which has passed through the fixing means without recording an image, to a predetermined feeding start position through a predetermined inner conveying path. Image forming apparatus. 2. An image forming apparatus that has a fixing unit that heat-presses a recording medium to fix an image, and pre-feeds the recording medium to a predetermined position before writing an image, and is pre-fed to the predetermined position. After that, the recording medium that has passed through the fixing means without being recorded with an image is returned to a predetermined feeding start position through a predetermined inner conveying path, and a re-feeding means, and pre-feeding to the predetermined position. After that, the time measuring means for measuring a predetermined permissible time until the image recording is canceled without receiving the image recording permission from the data source, and the feeding back of the recording medium previously fed from the time measuring state by the time measuring means. Determination means for determining whether or not
An image forming apparatus comprising: a control unit that controls the drive of the return feeding unit based on the determination result of the determination unit. 3. An image forming apparatus having a pre-feeding unit for pre-feeding a recording medium to a predetermined position before writing an image, wherein the recording medium pre-fed to the predetermined position is conveyed through a predetermined inner conveying path. Return feeding means for feeding back to a predetermined feeding start position, timing means for timing a predetermined stop time of the recording medium pre-fed to the predetermined position, and detection of the temperature in the vicinity of the fed recording medium Temperature detecting means, setting means for variably setting a predetermined stop time measured by the time measuring means based on the temperature detected by the temperature detecting means, and the predetermined stop time set by the setting means for the time measuring means. The image forming apparatus further comprises: a control unit that determines whether or not the time has been counted and controls the driving of the return feeding unit. 4. The image forming apparatus according to claim 1, wherein the predetermined inner conveying path is a double-sided / multiplexing conveying path leading from the fixing section to the intermediate tray. 5. The image forming apparatus according to claim 1, wherein the predetermined inner conveyance path is a return conveyance path that extends from the downstream side of the fixing unit to the upstream side of the sheet feeding. 6. The image forming apparatus according to claim 1, wherein the predetermined inner conveying path is a sheet discharging conveying path that is discharged from the fixing section and communicates with the sheet feeding and stacking section. 7. An image forming apparatus having a pre-feeding means for pre-feeding a recording medium to a predetermined position before writing an image, wherein the recording medium pre-fed to the predetermined position is fed from an upstream side of a transfer section. Return feeding means for feeding back to a predetermined feeding start position through a return conveyance path leading to the stacking section, and timing means for measuring a predetermined stop time of the recording medium pre-fed to the predetermined position. An image forming apparatus comprising: a control unit that determines whether or not the time measuring unit has timed the predetermined stop time, and controls the drive of the returning and feeding unit. 8. The first side or the second side of the recording medium to be fed.
In an image forming apparatus having a fixing unit for transferring and fixing an image on a surface and a feeding / conveying path, a temperature detecting unit for detecting a temperature of the fixing unit and a recording medium to be fed are first.
The determining means for determining whether or not the image is recorded on the first side and the image fixing temperature for the second side of the recording medium fed to the fixing means based on the determination result by the determining means are the image fixing temperature for the first side. An image forming apparatus comprising: a control unit that controls the fixing temperature of the fixing unit so that the fixing temperature is different. 9. The first side or the second side of the recording medium to be fed.
In an image forming apparatus having a fixing unit for transferring and fixing an image on a surface and a feeding / conveying path, a temperature detecting unit for detecting a temperature of the fixing unit and a recording medium to be fed are first.
A determination unit that determines whether or not the image is recorded on the first side, and a second image fixing temperature for the second side of the recording medium that is fed to the fixing unit based on the determination result by the determination unit is set to the first image on the first side An image forming apparatus comprising: a control unit that controls the fixing temperature of the fixing unit so as to be lower than the fixing temperature. 10. A time measuring means for measuring an elapsed time from the setting of the second image fixing temperature to the fixing means,
10. The control means restores the second image fixing temperature set in the fixing means to the first image fixing temperature based on the timed state of the timer for a predetermined time.
The image forming apparatus described. 11. The image forming apparatus according to claim 9, wherein the fixing unit is a fixing roller unit including a fixing roller, a heater for heating the fixing roller to a predetermined temperature, and a pressure roller. apparatus. 12. The fixing means comprises a fixing film, a ceramic heater for heating the fixing film to a predetermined temperature,
The image forming apparatus according to claim 9, which is a fixing unit including a pressure roller. 13. Pre-feeding means for pre-feeding a recording medium to a predetermined position before writing an image, and returning the recording medium pre-fed to the predetermined position to a predetermined feeding start position via an inner conveying path. Recording of an image forming apparatus having return feeding means for feeding, temperature detecting means for detecting the temperature in the vicinity of the fed recording medium, and timing means for timing a predetermined stop time of the recording medium pre-fed to the predetermined position. In the medium feeding method, a time measuring step of measuring a stop time of the recording medium pre-fed to the predetermined position by a time measuring means,
A temperature detecting step of detecting the temperature in the vicinity of the fed recording medium by a temperature detecting means, a setting step of variably setting a predetermined stop time measured by the time measuring means based on the detected temperature, and a set predetermined A method of feeding a recording medium to an image forming apparatus, comprising: a returning step of determining whether or not the time measuring means has timed the stop time and starting driving of the returning and feeding means.