JP2000267544A - Electrophotographic recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic recording device in which idle operating time in an image forming section is reduced and the occurrence of toner degradation before printing is prevented. SOLUTION: When a writing sensor 57 detects the fact that a transfer paper has passed the sensor 57 and transmitted to an image forming section, a clutch 50 is turned OFF by an OFF signal from the sensor 57. At that time, the rotation driving force of a photosensitive drum of the section is cut with the timing when the paper 37 passes between a photosensitive drum 9 and a transfer roller 15 after the generation of the OFF signal of the sensor 57 and an idle shaft 51 is rotated for a prescribed amount, Then, a main motor 5 continuos its rotation and a clutch gear 52 races with respect to the shaft 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic recording apparatus such as an electrophotographic printer or an electrophotographic copying machine, and more particularly, to an improvement in a structure of a fixing unit in an electrophotographic recording apparatus and a method of driving the fixing section.

[0002]

2. Description of the Related Art FIG. 8 is a diagram showing a paper traveling path in an electrophotographic printer.

In the figure, 1 is a paper cassette, 2 is a hopping motor, 3 is a hopping roller, and 4 is a sub-roller. The hopping motor 2 drives the hopping roller 3 and the sub-roller 4 via a gear train (not shown) to feed out the paper stored in the paper cassette 1.

Reference numeral 5 denotes a main motor which is driven at the same time as the paper is fed out, and which feeds a feed roller 6, a registration roller 7, and an image forming unit 8 which constitutes an image forming unit via a gear train (not shown). The drum 9, the heat roller 11 of the fixing unit 10, and the discharge roller 12 are rotated. The image forming unit 8 includes an LED head 13, a developing roller 14, and the like in addition to the photosensitive drum 9, and the sheet fed from the sheet cassette 1 is once hit against the registration roller 7 to reduce the skew. After the correction, the sheet is sent to the image forming unit 8.

In the image forming section, an electrostatic latent image is formed on the photosensitive drum 9 whose surface is uniformly charged by the light irradiated from the LED head 13, and the electrostatic latent image is formed by the developing roller 14. Apply toner. The toner image developed on the photosensitive drum 9 is transferred to a sheet by a transfer roller 15, and the transfer sheet is transferred to a fixing unit 10.

In the fixing unit 10, after the image of the sheet is thermally fixed between the heat roller 11 and the backup roller 16, the sheet is ejected by the ejection roller 12 in a face-down state in the direction of arrow A at the top of the apparatus. When the up stacker 17 is opened, the sheet is discharged in the direction of arrow B.

FIG. 9 is a detailed explanatory view showing a gear train of a conventional main motor drive system.

Here, the main motor 5 serves as the same drive source, and simultaneously rotates the feed roller 6 for feeding out the paper, the photosensitive drum 9 in the image forming section, and the heat roller 11 in the fixing section. I have.

That is, when the main motor 5 is rotated in the direction of arrow C, the first reduction gear 18, the second reduction gear 19,
The driving force is transmitted to the image forming unit 8 via the first idle gear 20 and the drum gear 21 to rotate the photosensitive drum 9 in the direction of the arrow. Also, the first idle gear 2
From 0, the third reduction gear 22, the second idle gear 23,
It is also transmitted to the registration gear 25 and the feed roller gear 26 via the third idle gear 24, and rotates the registration roller 7 and the feed roller 6 in the direction of the arrow, respectively. Further, the first reduction gear 18 includes a fourth reduction gear 29,
The heat roller 11 is rotated via the fourth idle gear 30 and the heat roller gear 31. The heat roller 1
The backup roller 16, which is in pressure contact with 1, rotates with the rotation of the heat roller 11.

The registration roller 7 and the feed roller 6 are provided with clutches 34 and 35 on their respective drive shafts in order to correct the skew of the sheet fed to the image forming unit 8. The clutch 35 of the feed roller 6 is turned on simultaneously with the hopping of the sheet from the sheet cassette 1, and rotates the feed roller 6 by driving the main motor 5 to convey the sheet to the registration roller 7. When the trailing edge of the sheet passes through the feed roller 6, the clutch 35 is turned off and the driving stops. On the other hand, the clutch 34 of the registration roller 7 is off from the beginning, and the drive transmission from the main motor 5 is cut off, that is, the rotation of the registration roller 7 is stopped. Therefore, the skew is corrected by the feed roller 6 transporting the leading end of the paper 37 to the pressure roller 36 which is in pressure contact with the registration roller 7 and abutted thereon.

Thereafter, when the clutch 34 is turned on and the registration roller 7 starts rotating by the transmission of the drive of the main motor 5, the sheet 37 whose skew has been corrected is conveyed to the image forming section. Further, the heat roller gear 31 of the fixing unit 10 is connected to the discharge roller 12 via a gear train (not shown), and the paper 37 can be discharged to the outside of the apparatus by transmitting a driving force thereto.

[0012]

A conventional electrophotographic recording apparatus comprising an image forming unit 8 and a fixing section 10 using the main motor 5 as the same driving source is advantageous in terms of miniaturization of the apparatus. However, until the paper is removed from the paper cassette and discharged by the discharge rollers,
The main motor 5 must be driven at all times. Therefore, in the image forming unit 8, the photosensitive drum 9 keeps rotating even after a series of electrophotographic processes is completed. That is, even when the paper 37 does not pass between the photosensitive drum 9 and the transfer roller 15, there is a problem that the photosensitive drum and various rollers continue an unnecessary idle operation.

[0013] Even in the conventional electrophotographic recording apparatus, when continuous printing is performed in the copy mode, the paper is continuously hopped from the paper cassette. Yes. But,
In the case of intermittent printing or printing with low print duty, unnecessary rotation of the photosensitive drum 9 is a problem. In the case of intermittent printing, the photosensitive drum 9 of the image forming unit 8 is used until one sheet 37 is discharged by the discharge roller 12.
Etc. continue to rotate. In addition, in low-print-duty printing, the amount of toner consumed in one intermittent printing is small.
The number of times the toner supplied to the toner is stirred increases, and the stirring time also increases. That is, the toner is unnecessarily agitated before the toner supplied to the image forming unit 8 is used up, so that the toner deteriorates before being used for printing.

FIGS. 10 and 11 are diagrams showing the print quality with respect to the number of rotations of the photosensitive drum. Each of the vertical axes has a low print duty of about 5%, in the copy mode (continuous printing) and the intermittent printing mode (1P / J).
The toner fluidity level (FIG. 10) and the density level of solid black printing (FIG. 11) are shown. The rotation number of the photosensitive drum shown on the horizontal axis is in units of 1000 rotations (Kround). When the remaining amount of toner in the image forming unit becomes small and the toner life is detected by a unit not described in detail, a new rotation is automatically performed. The toner was added and the evaluation continued until the end of the life of the image forming unit itself.

The figure shows the minimum values of the toner fluidity level and the solid black printing density level near the toner life. From these figures, it can be seen that in the case of intermittent printing (1P / J), compared to the case of the copy mode (continuous printing), the toner fluidity near the toner life and the decrease in density at the time of solid printing are remarkable. I understand.

As described above, in the electrophotographic recording apparatus having the conventional configuration, when the toner is deteriorated, its fluidity is reduced, and the density in solid black printing is reduced, and halftone printing such as gray scale becomes unclear. Or the fixability deteriorates. Therefore, there has been a problem that if the idle operation time in the image forming section is long, the print quality is adversely affected.

An object of the present invention is to provide an electrophotographic recording apparatus in which the idling operation time in an image forming unit is reduced to prevent toner deterioration before printing by solving the above-mentioned problems. With the goal.

[0018]

An electrophotographic recording apparatus according to the present invention is an electrophotographic recording apparatus in which an image forming section and a fixing section are driven by the same drive source, and wherein a driving force is transmitted to the image forming section. A clutch provided in a path, and clutch control means for controlling the clutch so as to stop driving the image forming unit at a timing when the transfer paper passes through the image forming unit.

Further, according to the present invention, there is provided an electrophotographic recording apparatus, comprising: an image forming unit; a fixing unit driven by a driving source different from the image forming unit; and a timing at which a transfer sheet passes through the image forming unit. Drive control means for stopping the drive of the image forming unit.

A clutch disposed on a transmission path of a driving force to the fixing unit; a pressing unit for pressing a transfer sheet passing through the fixing unit with a plurality of different pressing forces; Control means for switching control of the pressing force of the means while the clutch is off.

Further, the pressing unit is rotated by a driving force to the fixing unit, the spring being configured to press the pressing roller disposed opposite to the heat roller of the fixing unit, and the heat of the pressing roller is adjusted. And a cam member for switching the pressing force to the roller.

[0022]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described. Embodiment 1 FIG. FIG. 1 is a detailed explanatory diagram illustrating a gear train of a main motor drive system in the electrophotographic recording apparatus according to the first embodiment. In FIG. 1, FIG.
The same parts as those of the first gear train are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 1, reference numeral 50 denotes the first idle gear 2.
0 is a clutch provided on the shaft 51. A clutch gear 52 having the same number of teeth as the first idle gear 20 fixed to the idle shaft 51 is fixed on the same axis as the idle shaft 51. When both clutches are connected by the clutch 50, the first reduction gear 18, The driving force of the main motor 5 is transmitted to the image forming unit 8 via the second reduction gear 19.

FIG. 2 is a detailed explanatory view showing a clutch unit in the electrophotographic recording apparatus according to the first embodiment.

When print data is supplied to the image forming unit 8 and a print start command is given, the main motor 5 is driven. Thereby, the rotational driving force is transmitted to the clutch gear 52 via the second reduction gear 19. Clutch gear 52
Is connected to the clutch 50, so that the clutch 50
In the case of N, the idle shaft 51 rotates together with the clutch gear 52. Reference numeral 53 denotes a gear box that rotatably supports the idle shaft 51, and reference numerals 54a and 54b denote bearings incorporated in the gear box 54.

In the gear box 53, a knock pin 56
When the idle shaft 51 is rotated by the rotation of the clutch gear 52, the first idle gear 20 is fixed to the idle shaft 51, and the drum gear 21 and the third reduction gear 22 meshed with the first idle gear 20 Rotation is transmitted. Further, the drum gear 21 and the third reduction gear 22 are configured to rotationally drive the photosensitive drum 9 and the registration roller 7, respectively.

Returning to FIG. 1, reference numeral 57 denotes a writing sensor for detecting the timing of writing the electrostatic latent image on the photosensitive drum 9, and is disposed at an intermediate position between the registration roller 7 and the photosensitive drum 9.

The writing sensor 57 is connected to a control unit (not shown), and when it detects that the transfer paper 37 has passed through the writing sensor 57 and has been sent to the image forming unit, the clutch 50 is turned off by the OFF signal of the sensor 57. Is what you do. At this time, the rotation driving force of the photosensitive drum of the image forming unit is cut off by rotating the idle shaft 51 by a predetermined amount after the OFF signal of the sensor 57 so that the transfer paper passes between the photosensitive drum 9 and the transfer roller 15. It is timing.
After that, the main motor 5 continues to rotate, so that the clutch gear 52 idles with respect to the idle shaft 51.

Hereinafter, the intermittent printing operation in the electrophotographic recording apparatus having the above configuration will be described.

Normally, when performing intermittent printing on each sheet using an electrophotographic recording apparatus, the main motor 5 is first driven to prepare for printing in the image forming section.

Next, the paper accommodated in the paper cassette 1 is fed out, once abutted against the registration rollers 7 to correct the skew, and then sent to the image forming unit 8. The operation so far is the same as that of the conventional device.

Next, when the control unit (not shown) detects that there is no continuous print data, the idle shaft is moved by a predetermined amount after the transfer paper passes through the writing sensor 57 for detecting the timing of writing the electrostatic latent image on the photosensitive drum. After rotating the photosensitive drum 9 through the idle gear 20 and the drum gear 21 by rotating the clutch 51, the clutch 50 is turned off.
Is done. This makes it possible to stop the rotation of the photosensitive drum 9 before the sheet on which the toner image has been transferred by the photosensitive drum 9 passes through the fixing unit 10 and is discharged.

In the electrophotographic process at the time of the intermittent printing operation, when the cleaning sequence is executed every time, the photosensitive drum 9 is moved until the sheet passing through the transfer roller is discharged.
Need to be operated at idle. Therefore, by counting the number of printed sheets and executing the cleaning sequence when the number reaches a certain number, the idle operation time in the image forming unit can be suppressed, and good print quality can be maintained.

As described above in detail, in the electrophotographic recording apparatus of the first embodiment, the clutch is provided in the transmission system of the rotational driving force to the image forming unit 8 and the registration roller 7 is provided.
The drive is stopped at the timing when the transfer paper sent from the printer passes the image forming unit 8, so that unnecessary idle operation time of the photosensitive drum at the time of intermittent printing can be reduced. Accordingly, it is possible to prevent a decrease in the fluidity of the toner and a decrease in the print density, and it is possible to secure good print quality when printing is performed by repeatedly supplying the toner until the life of the image forming unit 8 reaches its end. . Embodiment 2 FIG. The electrophotographic recording apparatus according to the second embodiment is different from the first embodiment in that a dedicated independent motor for driving the fixing unit and the discharge roller is used without relying on the drive transmission from the conventional main motor. Are different.

FIG. 3 is a detailed explanatory view showing a gear train of a fixing unit drive system in the electrophotographic recording apparatus according to the second embodiment.

In the first embodiment, as shown in FIG.
Although the driving force was transmitted from the reduction gear 18 to the heat roller 11 via the fourth reduction gear 29, in the second embodiment,
The fourth reduction gear 29 is removed, and another motor is prepared for driving the heat roller 11 to rotate a drive system after the fixing unit including the discharge roller via a gear train shown in FIG. It is. Although not shown in FIG. 3, the configuration of the driving system such as the registration roller 7 and the image forming unit 8 is similar to that of the first embodiment.

In FIG. 3, reference numeral 60 denotes a motor gear which is rotated while being switched in the direction of arrow D or E. When the motor gear 60 is rotated in the direction of arrow D, the driving force of the motor gear 60 is changed according to the on / off state of the first clutch 80.
When the rotation is performed in the direction of arrow E, the lift cam is driven via the second clutch 70, so that the backup roller 16
Is to control the pressing force.

FIG. 4 is a detailed explanatory view showing a gear connecting portion in the electrophotographic recording apparatus according to the second embodiment.

As shown in FIGS. 3 and 4, the first clutch 80 is connected to the motor gear 60 via the reduction gear 61.
Is engaged with the clutch gear 62. The idle shaft 81 of the first clutch 80 includes a gear box 82
When the first clutch 80 is turned on, it rotates in the same direction as the clutch gear 62.
An idle gear 63 having the same number of teeth as the clutch gear 62 is fixed to the idle shaft 81, and a heat roller gear 65 meshes with the idle gear 63 via an idle gear 64. Therefore, when the motor gear 60 rotates in the direction of arrow D, the heat roller 1
1 can be rotated together with the heat roller gear 65 in the direction of the arrow.

On the other hand, the backup roller 16 is
The compression coil springs 68 are respectively provided at a and 69b.
The heat roller 11 is pressed against the heat roller 11 by a and 68b, and rotates with the rotation of the heat roller 11 in that state. The backup roller 16 is a rubber roller made of heat-resistant silicone rubber or the like. The backup roller 16 is rotatably supported by bearings 69 a and 69 b incorporated at both ends thereof.
Is controlled.

That is, a clutch gear 71 is connected to the second clutch 70, and the clutch gear 71 is engaged with the motor gear 60. The rotating shaft of the clutch gear 71 is an idle shaft 7 to which the idle gear 72 is fixed.
3, and the idle shaft 73 is rotatably supported by a gear box 74. A cam control gear 75 meshes with the idle gear 72,
The cam control gear 75 is fixed to a cam shaft 76 having substantially the same length parallel to the backup roller 16. Lift cams 77 a and 77 b having different distances to the cam surface are fixed to both ends of the cam shaft 76, and a slit disc 78 is fixed to the cam shaft 76 integrally with the cam control gear 75.

The slit disk 78 has slits # 1 to # 5, which will be described in detail later.
By detecting the slit position at 3, the rotation angle of the camshaft 76 is controlled. The spring holders 79a and 79b incorporate the bearings 69a and 69b of the backup roller 16 and the compression coil springs 68a and 68b, respectively. The spring holders 79a and 79b are arranged so as to contact the cam surfaces of the lift cams 77a and 77b at point Χ. Thus, when the second clutch 70 is turned on, the motor gear 6
The driving force of 0 is transmitted to the cam control gear 75 via the idle gear 72, and the lift cams 77a and 77b rotate by a predetermined angle together with the cam shaft 76, so that the pressing force of the backup roller 16 on the heat roller 11 is determined.

The driving force is transmitted from the heat roller gear 65 or the idle gear 63 to the discharge roller. However, since the driving force is not directly related to the present invention, the description is omitted here.

Hereinafter, the operation of the fixing unit driving system will be described with reference to FIGS.

To fix the transferred image, the motor gear 60 is rotated in the direction of arrow D in order to drive the heat roller 11 counterclockwise (CCW) as shown by the arrow in FIG. At the same time as driving the motor, the first clutch 80 is turned on, and the clutch gear 62 and the idle shaft 63 are connected.
Thereby, the heat roller 11 is rotationally driven via the gear train.

At the same time, the clutch 70 is turned off,
By causing the clutch gear 71 to idle with respect to the idle shaft 73, the driving of the camshaft 76 is stopped, and the lift cams 77a and 77b are held at predetermined positions. Also,
The lift cams 77a and 77b abutting on the spring holders 79a and 79b change the pressing pressure of the backup roller 16 against the heat roller 11 depending on the rotation angle thereof. And backup roller 16
Width of the nip formed by the pressure contact part with the rubber (the amount of crushing of the rubber part)
Can be controlled.

Next, a description will be given of the jam release operation when the pressure of the backup roller 16 on the heat roller 11 is changed according to the sheet thickness or when a sheet jam occurs.

FIG. 5 is a diagram for explaining the pressurized state of the backup roller 16.

When the pressing force of the backup roller 16 on the heat roller 11 is changed, the first clutch 80 is turned off, the clutch gear 63 idles with respect to the idle shaft 81, and the heat roller 11 is stopped. . In this state, when the clutch 70 is turned on simultaneously with the rotation of the motor gear 61, the clutch gear 71 and the idle shaft 73 are connected, and the cam control gear 75 is driven to rotate via the idle gear 72. Lift cams 77a, 77b fixed to both ends of camshaft 76 by rotation of cam control gear 75
The pressing force of the backup roller 16 can be changed by rotating the spring holders 79a and 79b up and down simultaneously (only one side is shown). At this time, since the cam control gear 75 rotates integrally with the slit disk 78, the photo sensor 83
By receiving the position signal from the slit disk 78, the lift cams 77a and 77b can be controlled to a position corresponding to the lift amount.

FIGS. 6 and 7 show the relationship between the shape of the lift cam 77 and the slit position of the slit disk 78. FIG.

FIG. 6 shows a case where the home position of slit # 1 is detected. Lift cam 77
Is in contact with the spring holders 79a and 79b at a position where the pressing force of the backup roller 16 against the heat roller 11 is minimized. FIG. 7 shows a case in which the slit # 5 at which the pressing force is maximized is detected.

Heat roller 1 of backup roller 16
In order to change the pressurizing force to the heat roller 11, the first clutch 80 is turned off, the drive transmission to the heat roller 11 is cut off, and at the same time, the motor gear 60 is rotated in the direction of arrow D (CCW direction). To perform the operation of detecting the slit # 1 as the home position. Since the detection interval (time) of the slit # 1 and the slit # 2 is shorter than the other slit intervals, the slit # 1 which is the home position can be recognized. Thereafter, the motor gear 60 is stopped in any position from the slit # 2 to the slit # 5 by rotating the motor gear 60 in the direction of the arrow E (CW direction). slit#
The positions of the lift cams 77 corresponding to the slits # 2 to # 5 correspond to the sheet thickness set in advance, and can be freely selected by input setting from an operation panel (not described in detail).

When a paper jam occurs, the backup roller 1 is controlled based on, for example, the information of the cover open.
By driving the lift cam 77 to the position of the slit # 2 where the pressing force on the heat roller 11 of No. 6 is the smallest, it is possible to easily clear the jam.

As described in detail above, by making the drive transmission after the fixing section including the discharge roller independent of the drive transmission of the image forming section, unnecessary transmission during intermittent printing is performed as in the first embodiment. Idle operation time can be reduced, preventing a decrease in toner fluidity and print density,
Good print quality can be secured until the life of the image forming unit.

Further, by making the driving after the fixing unit different, the pressing force of the backup roller 16 to the heat roller 11 is changed by setting from an operator panel or the like according to the thickness of the paper to be printed. This makes it possible to secure optimum fixing properties according to the sheet thickness.

Further, when a paper jam occurs in the fixing unit, by reducing the pressure applied to the heat roller 11 by the backup roller 16, additional effects such as easy removal of the jam can be obtained. Play.

[0057]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, the clutch disposed on the transmission path of the driving force to the image forming unit and the driving of the image forming unit are stopped at the timing when the transfer paper passes through the image forming unit. Since the clutch control means for controlling the clutch is provided so as to perform the above operation, unnecessary idle operation time of the photosensitive drum at the time of intermittent printing can be reduced.

According to the second aspect of the present invention, the image forming section includes:
A fixing unit that is driven by a drive source different from the image forming unit; and a drive control unit that stops driving of the image forming unit when transfer paper passes through the image forming unit. It is possible to prevent lowering of the printing property and lowering of the printing density, and it is possible to secure good printing quality until the life of the image forming section.

According to the third aspect of the present invention, the clutch provided on the transmission path of the driving force to the fixing unit and the pressurizing unit which presses the transfer paper passing through the fixing unit with a plurality of different pressing forces. Since the apparatus further includes a pressure unit and a control unit that controls switching of the pressure contact force of the pressure unit while the clutch is off, optimal fixability according to the sheet thickness can be secured.

According to the fourth aspect of the present invention, the pressurizing means rotates by a driving force to the fixing unit, the spring pressing the pressurizing roller disposed opposite to the heat roller of the fixing unit. And a cam member for switching the pressing force of the pressure roller to the heat roller, so that the backup roller is applied to the heat roller by setting from an operator panel or the like according to the thickness of the paper to be printed. The pressure can be easily changed.

[Brief description of the drawings]

FIG. 1 is a detailed explanatory diagram illustrating a gear train of a main motor drive system in an electrophotographic recording apparatus according to a first embodiment.

FIG. 2 is a partial detailed view of a clutch unit showing one embodiment of the present invention.

FIG. 3 is a detailed explanatory diagram illustrating a gear train of a fixing unit driving system in the electrophotographic recording apparatus according to the second embodiment.

FIG. 4 is a detailed explanatory view showing a gear connecting portion in the electrophotographic recording apparatus according to the second embodiment.

FIG. 5 is a diagram for explaining a pressurized state of a backup roller.

FIG. 6 is a diagram showing a relationship between a shape of a lift cam and a slit position of a slit disk.

FIG. 7 is a diagram showing a relationship between a shape of a lift cam and a slit position of a slit disk.

FIG. 8 is a diagram showing a paper traveling route in a conventional electrophotographic printer.

FIG. 9 is a detailed explanatory view showing a gear train of a conventional main motor drive system.

FIG. 10 shows data obtained by comparatively examining toner fluidity with respect to the number of photosensitive drum rotations in a copy mode and intermittent printing at a low print duty of about 5%.

FIG. 11 is data obtained by comparing and investigating the solid black density with respect to the number of rotations of the photosensitive drum in the copy mode and intermittent printing at a low print duty of about 5%.

[Explanation of symbols]

1 paper cassette, 2 hopping motor, 3 hopping roller, 4 sub-roller, 5 main motor, 6 feed roller, 7 registration roller,
Reference Signs List 8 image forming unit, 9 photosensitive drum, 10 fixing unit, 11 heat roller, 12 discharge roller, 1
3 LED head, 14 developing roller, 15 transfer roller, 16 backup roller, 17 face-up stacker, 18 first reduction gear, 19 second reduction gear, 20 first idle gear, 21 drum gear, 22 third reduction gear, 23 second idle gear, 24 third idle gear, 25 registration gear, 26 feed roller gear, 29 fourth reduction gear, 30 fourth idle gear, 31 heat roller gear, 34, 35 clutch, 36 pressure roller, 37 paper, 50 Clutch, 51 idle shaft, 52 clutch gear, 53 gear box, 54a, 54b bearing, 56 knock pin,
57 writing sensor, 58 transfer roller, 60
Motor gear, 61 reduction gear, 62 clutch gear, 63, 64 idle gear, 65 heat roller gear, 68a, 68b compression coil spring,
69a, 69b bearing, 70 second clutch, 71
Clutch gear, 72 idle gear, 73 idle shaft, 74 gear box, 75 cam control gear, 76 cam shaft, 77a, 77b
Lift cam, 78 slit disc, 79a, 7
9b spring holder, 80 first clutch, 8
1 idle shaft, 82 gear box, 83
Photo sensor.

Claims (4)

[Claims] 1. An electrophotographic recording apparatus in which an image forming unit and a fixing unit are driven by the same drive source, wherein a clutch disposed on a transmission path of a driving force to the image forming unit; An electrophotographic recording apparatus comprising: a clutch control unit that controls the clutch so that the driving of the image forming unit is stopped at a timing when a transfer sheet passes. 2. An image forming unit, a fixing unit driven by a drive source different from the image forming unit, and a drive control for stopping the driving of the image forming unit at a timing when a transfer sheet passes through the image forming unit. And an electrophotographic recording apparatus. 3. A clutch disposed on a transmission path of a driving force to the fixing unit, a pressurizing unit configured to press a transfer sheet passing through the fixing unit with a plurality of different pressing forces, and the pressurizing unit. 3. An electrophotographic recording apparatus according to claim 2, further comprising control means for switching control of the pressing force of said means while said clutch is off. 4. The pressure unit is rotated by a driving force applied to the fixing unit, the spring being configured to press the pressure roller facing the heat roller of the fixing unit. 4. An electrophotographic recording apparatus according to claim 3, further comprising a cam member for switching a pressing force to the roller.