JPH0954537A - Image forming device and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to negate the beat sounds generated by the resonance with the housing of a laser optical system while a second driving source shifts from high-speed rotation to low-speed rotation by changing over the rotating speed of the first driving source after the rotating speed of a second driving source for rotationally driving a rotating body for scanning which scans a laser beam is changed over from a high speed to a low speed. SOLUTION: The rotating speeds of a main motor 19, a polygon motor 20 and a fan motor 38 are changed over at the time of image forming operation and during standing-by for operation. The certain part of the time during the time the polygon motor 20 shifts from the high-speed rotation to the low-speed rotation is delayed T by the prescribed time from T1 and is superposed on the time during the operation of the main motor 19 when the timing for changing over the main motor 19 is defined as T1 and the timing for changing over the polygon motor 20 as T. As a result, the beat sounds generated by the resonance with the housing while the polygon motor 20 shifts from the high-speed rotation to the low-speed rotation are superposed on the rotating sounds of the main motor 19 and are negated.

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 and an image forming method applied as an electrophotographic apparatus, for example.

[0002]

2. Description of the Related Art In this type of image forming apparatus, an image read by an original reading section is sent as laser light to a polygon mirror, and the rotation of the polygon mirror scans the surface of a photoconductor through an optical system. Some form an electrostatic latent image.

The polygon mirror is rotatably driven by a drive motor (second drive source), and the drive motor lowers the level of noise generated from the motor itself when the copying operation shifts from the copying operation to the standby status. At the same time, in order to suppress power consumption, the rotational speed can be switched so as to change from high speed to low speed.

Further, the image forming apparatus is provided with a main motor (first drive source), and the main motor rotates the photosensitive member and causes the conveyor belt to travel to feed the paper to the fixing device. , The paper discharge roller is driven to rotate to discharge the paper to the outside of the main body of the apparatus, and this main motor also stops rotating from the constant speed rotation when shifting from the copying operation to the copying operation standby state. Can be switched to.

Further, the image forming apparatus is provided with a fan for cooling the cleaning portion including the photoconductor, a fan for sucking the paper when feeding the paper to the fixing device, and a fan for cooling the PC board. Also, these fans can be switched from high-speed rotation to low-speed rotation when shifting from the copying operation to the copying operation standby state.

Further, a fan for cooling the laser optical system is provided, and this fan can also be switched from the constant speed rotation to the rotation stop. By the way, there are several points where the natural vibration frequency of the housing accommodating the polygon motor and the rotation frequency of the motor resonate while the rotation frequency of the polygon motor changes from high speed rotation to low speed rotation. For this reason, the noise level is lower than that during the copying operation, but a humming noise is periodically generated.

[0007]

However, in the prior art, all of the timings for changing the rotational speeds of the fan and the motor, which are the sources of sound, were changed almost at the same time. Therefore, the trailing sound of the polygon motor, which takes a long time to reach the low speed rotation, is relatively conspicuous and annoying. Therefore, an object of the present invention is to provide an image forming apparatus and an image forming method capable of making the trailing sound of a scanning rotating body that scans a laser beam inconspicuous.

[0008]

SUMMARY OF THE INVENTION The present invention is a means for solving the problems, wherein a first driving source for rotationally driving a rotary member for image formation and an electrostatic latent image are provided. The scanning rotating body that scans the laser light for forming, the second driving source that rotationally drives the scanning rotating body, and the rotation speed of the second driving source are switched from high speed to low speed, and then And a switching means for switching the rotation speed of the first drive source.

According to a second aspect of the present invention, an image carrier for carrying an electrostatic latent image, a developing member for developing the electrostatic latent image, a carrying member for carrying the paper on which the developer image has been transferred, and a transfer to the paper. A first drive source that rotationally drives a fixing member that fixes an image, and a discharge member that discharges a fixed sheet of paper, a scanning rotator that scans a laser beam for forming an electrostatic latent image, and this scanning. After switching the rotation speed of the second drive source for rotatably driving the rotating body for use and the second drive source from the high speed to the low speed,
And a switching means for switching the rotation speed of the first drive source.

According to a third aspect of the present invention, a rotary fan for generating wind, a first drive source for rotationally driving the rotary fan, and a scanning rotation for scanning a laser beam for forming an electrostatic latent image. Body, a second drive source for rotationally driving the scanning rotary body, and a switching means for switching the rotational speed of the second drive source from high speed to low speed, and then switching the rotational speed of the first drive source. And.

According to a fourth aspect of the present invention, a rotating rotary fan for cooling the rotating member for image formation and a suction rotary fan for sucking a sheet onto the sheet conveying member are driven to rotate.
Drive source, a scanning rotator that scans a laser beam for forming an electrostatic latent image, a second drive source that rotationally drives the scanning rotator, and a rotation speed of the second drive source. And a switching means for switching the rotation speed of the first drive source after switching from high speed to low speed.

According to a fifth aspect of the present invention, there is provided a first driving step of rotationally driving a rotary member for image formation by a first drive source, and a rotary body for scanning a laser beam for forming an electrostatic latent image. A scanning step of scanning with a second driving source, and a second driving step of rotationally driving the scanning rotator by a second driving source;
After the rotational speed of the drive source is switched from the high speed to the low speed, the switching step of switching the rotational speed of the first drive source.

According to a first aspect of the present invention, the rotational speed of the first drive source is changed after the rotational speed of the second drive source that rotationally drives the scanning rotary member that scans the laser light is switched from high speed to low speed. By switching, the beat noise generated due to the resonance with the housing of the laser optical system during the transition from the high speed rotation to the low speed rotation of the second drive source is overlapped with the rotation sound of the first drive source to eliminate the beat noise. To be able to.

According to a second aspect of the present invention, after the rotational speed of the second drive source for rotationally driving the scanning rotary member for scanning the laser beam is switched from high speed to low speed, the image carrier, the developing member,
By switching the rotation speeds of the first drive source that rotationally drives the sheet conveying member, the fixing member, and the discharging member,
The beat noise generated by resonance with the housing of the laser optical system while the second drive source shifts from the high-speed rotation to the low-speed rotation is superimposed on the rotation sound of the first drive source so that the beat noise can be erased. To

According to a third aspect of the present invention, the rotational speed of the rotary fan is switched after switching the rotational speed of the second drive source for rotationally driving the scanning rotary member that scans the laser light from high speed to low speed. , So that the beat noise generated due to resonance with the housing of the laser optical system during the transition of the second drive source from the high speed rotation to the low speed rotation can be superimposed on the rotation sound of the rotating fan to eliminate the beat noise. .

According to a fourth aspect of the present invention, after the rotational speed of the second drive source for rotationally driving the scanning rotary body for scanning the laser light is switched from high speed to low speed, the cooling rotary fan and the suction rotary fan are rotated. By rotating the rotation speed of the first drive source for rotating the laser, the beat noise generated due to resonance with the housing of the laser optical system during the transition of the second drive source from the high speed rotation to the low speed rotation is rotated for cooling. The roaring noise can be drowned out by superimposing it with the rotating noises of the fan and the suction rotary fan.

According to a fifth aspect of the present invention, the rotational speed of the first drive source is changed after the rotational speed of the second drive source for rotationally driving the scanning rotary member for scanning the laser light is switched from high speed to low speed. By switching, the beat noise generated due to the resonance with the housing of the laser optical system during the transition from the high speed rotation to the low speed rotation of the second drive source is overlapped with the rotation sound of the first drive source to eliminate the beat noise. To be able to.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to an embodiment shown in FIGS. FIG. 1 shows the internal structure of an electrophotographic apparatus as an image forming apparatus. A in the figure
Is a main body of the apparatus, and a photoconductor drum as a rotatable image carrier is provided at a substantially central portion of the main body A of the apparatus. Around the periphery of the photosensitive drum 1, along the rotation direction,
A charging charger 2, an exposure unit 3, a developing device 4, a transfer charger 5, a peeling charger 6 and a cleaning device 7 are sequentially arranged.

A laser optical system 8 is provided on the upper side of the apparatus main body A. The laser optical system 8 includes a polygon mirror 9 as a rotatable rotating body for scanning a laser beam sent from a semiconductor laser (not shown), and an optical lens for passing the laser beam scanned by the rotation of the polygon mirror 9. 10. A polygon motor as a second drive source for rotating the reflection mirrors 11 and 12 that reflect the laser beam passing through the optical lens 10 and guide it to the photoconductor drum 1 and the polygon mirror 9 as a scanning rotator. It is composed of 20.

Further, a sheet conveying path 13 is provided on the lower side inside the apparatus main body A, and the transfer charger 5, the peeling charger 6 and the conveying belt are sequentially provided in the conveying path 13 in the sheet conveying direction. 14, and the fixing device 15,
A discharge roller 28, a gate 29, and a discharge roller 30 are arranged.

The fixing device 15 is a heat roller 17 for melting the toner, which is transferred onto a sheet as a medium, with heat.
(Controlled at about 200 ° C.), a press roller 18 is provided for rolling contact with the heat roller 17 and applying a load to the toner melted by the heat roller 17 to fix the toner on the paper.

A fan 1 is provided below the conveyor belt 14.
6 is provided, and the rotation of the fan 16 sucks the paper onto the conveyor belt 14. A substantially S-shaped transport path 27 is provided below the fan 16, and a plurality of feed rollers 31 are disposed in the transport path 27.

At the time of double-sided copying, the sheet is sent to the carrying path 27 and carried by the rotation of the gate 29. A stack portion 32 is provided below the transport path 27, and the sheets discharged from the transport path 27 are stacked on the stack portion 32 in an inverted state. The sheets stacked in the stack section 32 are taken out by the pickup roller 33, and are sent to the registration rollers 36 via the conveying path 35 by the rotation of the sheet feeding roller 34.

A document reading section 41 is provided on the upper side of the apparatus main body A.
The document reading section 41 is provided with first and second carriages 42 and 43. First carriage 4
2 is provided with an exposure lamp 44 and a first reflection mirror 45. The second carriage 43 is provided with second and third reflection mirrors 46 and 47. An optical lens 48 and a conversion element 49 for receiving and photoelectrically converting the reflected light are provided in the optical path of the reflected light reflected by the third reflection mirror 47.

A paper feed cassette 2 is provided on one side of the apparatus main body A.
5 is provided, and a large-capacity sheet feeding device 26 is provided below the sheet feeding cassette 25 to feed sheets. On the other side of the apparatus main body A, a paper discharge tray 27 that receives discharged paper is provided.

During image formation, the semiconductor laser oscillates a laser beam corresponding to document information, and the laser beam is applied to the polygon mirror 9 and scanned by the rotation of the polygon mirror 9. The scanned laser light is imaged on the surface of the photosensitive drum 1 via the optical lens 10 and the reflection mirrors 11 and 12. The surface of the photoconductor drum 1 is charged by the charging charger 2, and the charged surface is irradiated with the above-mentioned laser light, whereby an electrostatic latent image corresponding to the original image is formed. This electrostatic latent image is visualized by the toner sent to the developing device 4 and supplied from the developing device 4 by the rotation of the photosensitive drum 1.

On the other hand, at this time, a sheet is supplied from the sheet feeding cassette 25 or the sheet feeding device 26, and this sheet is sent to the image transfer portion between the photoconductor drum 1 and the transfer charger 5, and the transfer charger 5 moves. The image is transferred by the action. After the transfer, the image is separated from the photosensitive drum 1 and sent to the fixing device 15, where the image is fixed. After the fixing, the sheet is discharged to the outside of the apparatus main body A through the sheet discharging roller 28, the gate 29, and the discharging roller 30.

FIG. 2 is a block diagram showing the drive system of the image forming mechanism. Reference numeral 19 in the drawing denotes a main motor as a first drive source, and the main motor 19 causes the photosensitive drum 1,
The developing device 4, the cleaning device 7, the transport belt 14, the heat roller 17, and the paper discharge rollers 28 and 30 are rotationally driven.

A drive pulley 56 of the photosensitive drum 1 is connected to the main motor 19 via a first timing belt 51, and a drive gear 53 of the developing device 4 and a cleaning device are further connected via a second timing belt 52. The drive gear 54 of No. 7 and the power transmission gear 55 are connected.

The above-mentioned first and second timing belts 5
1, 52 are pressed by tension pulleys 65, 66, and tension is applied. The heat roller 17 is connected to the power transmission gear 55 via a pulley 57, and the heat roller 17 has a pulley 58, a gear 59, and a pulley 60.
It is connected to the drive gear 61 of the discharge roller 16 via.

Further, the heat roller 17 has a pulley 6
2, the gear 63 and the pulley 64 are connected to the drive gear 65 of the conveyor belt 14. Then, when the main motor 19 is rotationally driven, the first and second timing belts 51 and 52 are run. By the traveling of the first timing belt 51, the drive pulley 56 of the photosensitive drum 1 is rotated and the photosensitive drum 1 is rotated. By the traveling of the second timing belt 52, the drive gears 53 and 54 of the developing device 4 and the cleaning device 7 are rotated and driven.

The driving of the second timing belt 52 rotates the drive gear 55, drives the heat roller 17 via the pulley 57, and further drives the pulley 58, the gear 59, the pulley 60, and the gear 61. The paper discharge rollers 26 and 30 are rotationally driven.

Further, the pulley 62, the gear 63, the pulley 64
The conveyor belt 14 travels via the gear 65.
FIG. 3 shows rotary fans 21, 22, 24 arranged for the purpose of suppressing a temperature rise inside the apparatus due to an image forming operation.
Also, the fan 16 for adsorbing the paper is shown.

The rotary fan 21 cools the laser optical system 8 and the fan 22 cools the photosensitive drum 1 and the cleaning device 7. The rotary fan 24 cools the PC board 23 for controlling the functions of the apparatus.

The laser optical system 8 is housed in the casing 8a. FIG. 4 is a block diagram showing the main motor 19 whose rotation is switched by the switching means 70, the polygon motor 20, the fan motor 38 of the fans 21, 22 and 24, and the fan motor 39 of the fan 16.

The main motor 19, the polygon motor 20,
The rotation speed of the fan motor 38 is switched between the image forming operation and the standby operation. That is, the main motor 19 is switched from constant speed rotation to low speed rotation, the polygon motor 20 is switched from high speed rotation to low speed rotation, the fan motor 38 is switched from high speed rotation to low speed rotation, and the fan 39 is rotated from high speed rotation to low speed rotation. Can be switched to.

FIG. 5 shows the men motor 19 and the polygon motor 2.
FIG. 6 is a chart showing switching timings of 0, fans 16, 22, 24, and fan 21. This chart shows the polygon motor 20 which is accompanied by the generation of sound inside the apparatus when the image forming operation is switched to the standby state.
And the operation timings of the main motor 19 and the fans 16, 21, 22, 23.

When the switching timing of the main motor 19 is T ₁ and the switching timing of the polygon motor 20 is T, T ₁ is delayed from T by a predetermined time,
A portion of the polygon motor 20 having a time during which the high speed rotation is changed to the low speed rotation is overlapped with a time during which the main motor 19 is operating.

As a result, the jarring beat noise generated by the resonance of the polygon motor 20 rotating the polygon mirror 9 with the housing of the laser optical system during the transition from the high speed rotation to the low speed rotation overlaps with the rotation sound of the men motor 19. That is, the annoying sound will be erased.

The present invention is not limited to the above-mentioned embodiment, but may be as shown in FIG. That is, when the switching timing of the fans 16, 21, 22, 23 is set to T ₁ and the switching timing of the polygon motor 20 is set to T, T ₁ is delayed from T by a fixed time so that the polygon motor 20 changes from high speed to low speed. Fan 16, 21, 22, 2 is used for the part of the time when the transition to rotation occurs.
3 is superimposed on the time of operation.

As a result, the polygon motor 20 for rotating the polygon mirror 9 is resonated with the housing of the laser optical system during the transition from the high speed rotation to the low speed rotation. 23
It will be overlapped with the rotating sound of, and the annoying sound will be erased.

[0042]

As described above, the present invention has the following features.
In the one described, since the rotation speed of the second drive source that rotationally drives the scanning rotating body that scans the laser light is switched from the high speed to the low speed, the rotation speed of the first drive source is switched. The beat noise generated by resonance with the housing of the laser optical system during the transition of the drive source from the high speed rotation to the low speed rotation can be superimposed on the rotation sound of the first drive source to eliminate the beat noise.

According to a second aspect of the present invention, after the rotational speed of the second drive source for rotationally driving the scanning rotary member for scanning the laser beam is switched from high speed to low speed, the image carrier, the developing member, and
Since the rotational speeds of the first drive source that rotationally drives the sheet conveying member, the fixing member, and the discharging member are switched, the second drive source and the housing of the laser optical system are switched from the high speed rotation to the low speed rotation. The beat noise generated by resonance can be superimposed on the rotation noise of the first drive source to eliminate the beat noise.

According to the third aspect of the present invention, the rotational speed of the rotary fan is switched after the rotational speed of the second drive source for rotationally driving the scanning rotary member for scanning the laser light is switched from high speed to low speed. The beat noise generated due to resonance with the housing of the laser optical system during the transition of the second drive source from the high speed rotation to the low speed rotation can be superimposed on the rotation sound of the rotary fan to eliminate the beat noise.

According to a fourth aspect of the present invention, after the rotation speed of the second drive source for rotationally driving the scanning rotary body for scanning the laser light is switched from high speed to low speed, the cooling rotary fan and the suction rotary fan are rotated. Since the rotation speed of the first drive source that drives the rotation of the laser is switched, a roaring noise that is generated by resonance with the housing of the laser optical system during the transition of the second drive source from high speed rotation to low speed rotation is generated. And the roaring noise can be drowned out by superimposing it on the rotating sound of the suction rotary fan.

According to a fifth aspect of the present invention, the rotational speed of the first drive source is changed after the rotational speed of the second drive source for rotationally driving the scanning rotary member for scanning the laser light is switched from high speed to low speed. Since the switching is performed, the beat noise generated by the resonance with the housing of the laser optical system during the transition from the high speed rotation to the low speed rotation of the second drive source is superimposed on the rotation sound of the first drive source to eliminate the beat noise. You can

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an electrophotographic apparatus that is an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a drive system of an electrophotographic apparatus.

FIG. 3 is a perspective view showing an arrangement configuration of a rotary fan.

FIG. 4 is a block diagram showing a control system of a main motor, a polygon motor, and a fan motor.

FIG. 5 is a timing chart showing the operation of the main motor, polygon motor, and fan.

FIG. 6 is a timing chart showing the operation of the main motor, polygon motor, and fan, which is another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Photosensitive member (image bearing member) 16, 22, 24, 21 ... Fan (rotating member) 19 ... Main motor (first drive source) 9 ... Polygon mirror (scanning rotating member) 20 ... Polygon motor (second) Drive source) 70 ... Switching means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area G03G 21/20

Claims (5)

[Claims] 1. A first rotating member for rotating an image forming rotary member.
Drive source, a scanning rotating body that scans a laser beam for forming an electrostatic latent image, a second driving source that rotationally drives the scanning rotating body, and a rotation speed of the second driving source. An image forming apparatus comprising: switching means for switching the rotation speed of the first drive source after switching from high speed to low speed. 2. An image bearing member carrying an electrostatic latent image, a developing member for developing the electrostatic latent image, a carrying member for carrying a sheet on which a developer image is transferred, and a fixing member for fixing the transferred image on the sheet. ,
And a first drive source that rotationally drives a discharge member that discharges the fixed sheet, a scanning rotator that scans a laser beam for forming an electrostatic latent image, and a rotative drive of the scanning rotator. A second drive source; and a switching means for switching the rotation speed of the first drive source after switching the rotation speed of the second drive source from high speed to low speed. Image forming apparatus. 3. A rotary fan for generating wind, a first drive source for rotationally driving the rotary fan, a scanning rotary member for scanning a laser beam for forming an electrostatic latent image, and a scanning rotary member. A second drive source for rotationally driving the rotating body; and a switching means for switching the rotational speed of the first drive source after switching the rotational speed of the second drive source from a high speed to a low speed. An image forming apparatus characterized by the following. 4. A first driving source for rotationally driving a rotary cooling fan for cooling a rotary member for image formation and a suction rotary fan for sucking a sheet onto a sheet conveying member, and for forming an electrostatic latent image. Scanning rotary body for scanning the laser light of, a second drive source for rotationally driving the scanning rotary body, and a rotation speed of the second drive source after switching from high speed to low speed, An image forming apparatus comprising: a switching unit that switches a rotation speed of a drive source. 5. A first driving step of rotationally driving a rotating member for image formation by a first driving source, and a scanning step of scanning a laser beam for forming an electrostatic latent image with a scanning rotary member. A second driving step in which the scanning rotator is rotationally driven by a second driving source, and a rotational speed of the first driving source after switching the rotational speed of the second driving source from high speed to low speed. An image forming method, comprising: