JP2001100473A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of suppressing a temperature rise in the device to the minimum, and capable of attaining a quiet sound by suppressing the amplitude of the vibration of a driving means. SOLUTION: The image forming device is provided with an image forming means (process cartridge) 7 constituted of a recording material P feeding means (paper cassette 1, paper feeding roller 2), carrying means (carrying rollers 3a and 3b), and at least an image carrier (photoreceptor 8) and a developing means (developing unit 17), a light source means (laser scanner 5) for exposing on the photoreceptor 8, a transfer means (transfer roller 9) for transferring a developed image from the photoreceptor 8 to the recording material P, a driving means (motor 16) for driving the paper feeding means, the carrying means and the image forming means, and a fixing means (fixing unit 11) for heating and fixing the developed image on the recording material P, and in the image forming device, the paper feeding means-the transfer means-the fixing means are obliquely arranged upwards so that the fixing means may be positioned uppermost, and the driving means (motor 16) is arranged under a carrying path for carrying the recording material P to the paper feeding means-the transfer means-the fixing means, besides, the driving means is directly held at the inside of a conductive side wall constituting a housing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image forming apparatus for forming an image on a recording medium, such as an electrophotographic copying machine, a printer, a word processor, and a facsimile machine.

[0002]

2. Description of the Related Art The construction of a laser beam printer as an example of an image forming apparatus employing an electrophotographic system or another recording system is shown in FIGS.

FIGS. 6 and 7 are cross-sectional views of a conventional laser beam printer. In the laser beam printer, the conveyance path of a recording material from a paper feeding means to a transfer means to a fixing means is as shown in FIG. It is set substantially horizontal or substantially vertical as shown in FIG.

That is, in the laser beam printer shown in FIG. 6, a paper cassette 1 and a paper feed roller 2 as paper feeding means are provided at the right end of the apparatus, a transfer roller 9 is provided at the center as a transfer means, and a fixing means is provided at the left end. The fixing unit 11 is disposed substantially horizontally, and an image forming unit such as the process cartridge 7 and a light source unit such as the laser scanner 5 are disposed above the recording material conveying surface. The transfer to the recording material P and the heating and fixing of the visible image on the recording material P are sequentially performed.

In the laser beam printer shown in FIG. 7, a paper cassette 1 and a paper feeding roller 2 as paper feeding means are provided at a lower end of the apparatus, a transfer roller 9 is provided as a transfer means in the center, and a fixing means is provided at an upper end side. The fixing device 11 is disposed substantially vertically, and the process cartridge 7 is disposed on the side of the recording material conveying surface.
The light source means such as a laser scanner 5 and the like are arranged, and the feeding of the recording material P, the transfer of the developed image to the recording material P, and the heating and fixing of the developed image on the recording material P are sequentially performed.

In an image forming apparatus, a motor for driving a paper feed roller, a photoreceptor, a fixing device, and the like is held on a gear plate made of a metal material separate from a housing made of a resin material. Usually, it is attached to the housing on the side of the device by screws. Then, the paper feed roller and the like are rotated by transmitting the rotational power of the drive motor by a drive train provided on the gear plate.

[0007]

However, the conventional image forming apparatus has the following problems.

First, in a motor which is a driving source, there is a problem that a drive control driver substrate generates heat by passing an electric current, and heat is also generated from an internal winding coil by rotation of the motor. No. Since the motor is mounted on the gear plate, its heat is conducted to the gear plate, but is hardly conducted to the housing made of a resin material. As a result, the temperature in the entire apparatus rises, and the toner in the process cartridge hardens, and the bending rate of the optical lens in the light source unit changes. As a result, a good output image can be obtained. There was nothing.

Second, the motor is held by a separate gear plate, but the vibration caused by the eccentricity of the motor causes the vibration to propagate to the gear plate itself, and the vibration increases to increase the overall device. Drive noise is increased.

In order to solve the above-mentioned problems, the size of the entire apparatus is increased to move the motor which is a heat source away from the process cartridge or the light source means, or to provide a cooling fan to increase the temperature inside the apparatus. Countermeasures can be considered.

However, taking the above measures will increase the size of the apparatus and increase the manufacturing cost.

The present invention has been made in view of the above problems, and a first object of the present invention is to provide an image forming apparatus capable of minimizing a temperature rise in the apparatus and obtaining a good image over a long period of time. Is to provide.

A second object of the present invention is to provide an image forming apparatus in which the amplitude of the vibration of the driving means is reduced to reduce the level of the vibration itself and the operation sound is quiet.

Further, a third object of the present invention is to provide an inexpensive image forming apparatus capable of effectively convecting heat generated from an electric component to suppress a rise in temperature inside the apparatus.

A fourth object of the present invention is to provide an image forming apparatus which can cope with a high speed operation and has a high degree of design freedom.

[0016]

In order to achieve the above object, the present invention is directed to a recording material feeding means and a conveying means, an image forming means comprising at least an image carrier and a developing means, and an image forming means. Light source means for exposing on the carrier, transfer means for transferring a visible image from the image carrier to the recording material, driving means for driving the paper feeding means, the conveying means and the image forming means, and An image forming apparatus comprising a fixing unit for heating and fixing the visible image of the image forming apparatus, wherein the sheet feeding unit, the transfer unit, and the fixing unit are arranged obliquely upward so that the fixing unit is at an uppermost position. The means is arranged below a transport path for transporting the recording material from the sheet feeding means to the transfer means to the fixing means.

According to a second aspect of the present invention, in the first aspect of the present invention, the driving means is directly held inside a conductive side wall constituting a housing.

According to a third aspect of the present invention, in the first aspect of the present invention, a fin-shaped blade is provided on a rotor which rotates the driving means.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the driving means is constituted by a DC motor or a stepping motor.

Therefore, according to the first or second aspect of the present invention, the heat generated from the driving means is effectively conducted to the conductive side wall, so that the temperature rise in the apparatus is suppressed, and the heat is generated for a long period of time. Good images can be obtained. Further, since the amplitude of the vibration of the driving means is suppressed to be small by the housing having the large mass, the level of the vibration itself is reduced, and the noise of the image forming apparatus can be reduced.

According to the third aspect of the present invention, the air flow can be generated in the space below the conveying path of the recording material by the rotating blades, and the heat generated from the electrical unit is effectively convected. The temperature rise inside the machine can be suppressed.

According to the fourth aspect of the present invention, since the driving means disposed below the recording material conveyance path is constituted by a DC motor or a stepping motor, image formation which can cope with high speed and has a high degree of freedom in design is realized. A device can be obtained.

[0023]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view of a laser beam printer which is an image forming apparatus according to the present invention. The illustrated laser beam printer employs an electrophotographic system in which a photosensitive member is scanned with a laser beam for recording. .

In FIG. 1, reference numeral 1 denotes a paper cassette which is detachable from the apparatus main body, and a plurality of recording materials P are stacked in the paper cassette 1. The recording material P is separated and fed one by one by a paper feed roller 2 disposed on the upper front end side of the paper cassette 1, and is conveyed by transport rollers 3 a and 3.
b to the transfer section.

Reference numeral 4 denotes a registration sensor, and reference numeral 6 denotes a folding mirror. The registration sensor 4 synchronizes the leading edge position of the recording material P with the light emission timing of the laser scanner 5 serving as an exposure light source from a predetermined position on the recording material P. This is for drawing an image.

Reference numeral 7 denotes a process cartridge.
The process cartridge 7 includes a photosensitive member 8, a developing device 17,
Image forming means such as the charging roller 18 and the cleaner 19 are integrated. Reference numeral 9 denotes a transfer roller for transferring the visualized image on the photoconductor 8 onto the recording material P. Reference numeral 10 denotes a conveyance guide for guiding the recording material P after the visualized image transfer to the fixing device 11, and the fixing device 11 is a recording material. The visible image on P is fixed by heating.
Then, the recording material P on which the visible image has been fixed is discharged from the discharge roller 1.
2, the paper is discharged onto a paper discharge tray 14 formed integrally with the exterior cover 13.

(Conveyance Angle of Recording Material) As shown in FIG. 1, a paper feeding means composed of the paper cassette 1 and the paper feeding roller 2 and a visible image on the photoreceptor 8 are transferred onto the recording material P by the transfer roller 9. The fixing device 11 for heating and fixing the visible image on the recording material P is disposed obliquely upward on a substantially straight line with the fixing device 11 being the uppermost portion.

After the recording material P loaded on the paper cassette 1 is fed by the paper feed roller 2, it is conveyed to the transfer section by the conveyance rollers 3a and 3b along a substantially straight conveyance path. At the same time, the visible image is transferred to the fixing device 11 by the photoreceptor 8 and the transfer roller 9. Since the conveyance path of the recording material P during this period is substantially straight, the recording material P and the conveyance guide 1 when conveying the recording material P are used.
The rubbing noise with zero is reduced, and the recording material P is stably conveyed, so that the reliability of conveyance of the recording material P is improved.

Further, since the fixing device 11 is disposed at the uppermost portion of the recording material conveyance path, even when the printing operation is continuously performed, the heat generated from the fixing device 11 is not generated inside the outer cover 13. It is discharged from the illustrated louver part to the outside of the apparatus.

Further, since the process cartridge 7 and the laser scanner 5 are disposed below or beside the fixing device 11, they are not affected by the heat generated from the fixing device 11 and always have a good output. Images can be obtained.

In this embodiment, by making the recording material conveyance path substantially parallel or coincident with the diagonal line of the apparatus, various mechanisms can be effectively arranged, and the apparatus can be downsized. Becomes

[Laser Scanner Arrangement] FIG. 2
FIG. 3 is a perspective view of a main part of the laser beam printer shown in FIG. 1, and FIG. 3 is a cross-sectional view of a laser beam printer according to another embodiment.
As shown in FIG. 3, the polygon mirror 5a is arranged at the upper right or the upper left as shown in FIG. Here, in order to reduce the size of the image forming apparatus as much as possible, as shown in FIGS. 1 and 3, the photosensitive member is exposed from a direction substantially perpendicular to a recording material conveyance path from a sheet feeding unit to a transfer unit to a fixing unit. It is most effective to make a laser beam incident on the body 8. By adopting such a configuration, it is possible to minimize the depth and height dimensions of the device.

Further, since the scanner motor 5b for rotating the polygon mirror 5a is in a substantially horizontal state, there is no load acting on the bearing of the scanner motor 5b, and the bearing motor is worn away, thereby shortening the life of the scanner motor 5b. Does not occur, and the scanner motor 5b can be used for a long time.

According to the configuration shown in FIG. 1, the process cartridge 7 can be attached and detached substantially horizontally in the direction of the paper discharge tray 14, so as to remove jams in the apparatus and to remove the process cartridge 7 from the apparatus.
Can be exchanged from the same direction, and usability can be improved.

According to the configuration shown in FIG. 3, although the process cartridge 7 is attached and detached from above, the laser scanner 5 can be moved away from the fixing device 11, so that the laser scanner 5 This has the advantage of being less susceptible to the effect of temperature rise due to the heat of the substrate.

If the setting of the incident angle of the laser beam is performed as described in the present embodiment as described above, a large degree of freedom is provided for the arrangement of the laser scanner 5, so that the problems of usability and temperature rise can be avoided. Becomes easier.

(Regarding Layout of Electrical System) As shown in FIG. 1, an electrical unit 15 composed of an AC power source, a DC power source and a high-voltage power source is provided below a recording material transport path extending obliquely upward from a sheet feeding unit to a fixing unit. , And a large space area in the electrical unit 15 can be secured from the sheet feeding unit to the fixing unit. Therefore, a path of an air flow generated by heat generated from the electrical unit 15 can be secured.

Further, heat generated from the fixing unit 11 disposed above the electrical unit 15 is discharged to the outside of the apparatus from a louver (not shown) provided on the exterior cover 13. At this time, by providing a space between the rear surface of the fixing device 11 and the outer cover 13, it is possible to generate an air flow due to waste heat of the fixing device 11 in this portion.

Accordingly, as described above, a large space is provided below the fixing unit 11 and the electrical unit 15 is disposed in that space, and a space is provided on the rear side of the fixing unit 11 so that a cooling fan or the like is provided. Even without the above, it is possible to generate an air flow for waste heat from the electrical unit 15 to the fixing device 11, and it is possible to eliminate the heat buildup inside the apparatus and prevent the temperature inside the apparatus from rising. As a result, a fanless configuration is realized, cost reduction can be achieved, and noise generated from the fan is eliminated, so that the apparatus can be made quieter.

Further, since the space area below the recording material conveyance path which extends obliquely upward from the sheet feeding means to the fixing means can be effectively used, the electrical unit 15 is formed in an L-shaped configuration including a horizontal portion and a vertical portion. The layout can be made, and the efficiency as the electrical component 15 can be further increased. Specifically, by arranging the component or element that is a heat source on the vertical surface side and arranging the component or element that does not generate heat relatively on the horizontal surface side, the waste heat from the electrical component unit 15 is more efficiently performed. It becomes possible.

(Regarding Arrangement of Driving Source) The motor 16 as a driving source is constituted by a DC motor or a stepping motor, and as shown in FIGS. It is arranged below the recording material conveying surface to reach, and is directly mounted on the inside of a conductive side wall which is a part of the frame of the apparatus, and is attached by screws 26.

By arranging the motor 16 below the recording material transporting section as described above, it is possible to increase the size of the motor and reduce
It is possible to flexibly cope with a change to the C motor or the like. Thereby, for example, 10 ppm to 20 ppm
It is possible to easily achieve a high speed to ppm.

Further, by directly mounting the motor 16 inside the conductive frame 20 of the apparatus shown in FIG. 2, the heat generated by the motor 16 itself can be easily removed.
0 can be released to the entirety, the motor efficiency can be improved, and grounding can be easily performed, so that the total cost of the apparatus can be reduced.

Further, since the motor 16 is arranged inside the conductive frame 20, only the motor pinion projects outside, so that the thickness of the driving section can be reduced without interfering with the gear train arranged outside. It is possible to make the device thinner, so that the overall width of the device can be reduced and the device can be made smaller.

As shown in FIG. 4, both the motor 16 and the electrical unit 15 are disposed below the recording material transporting unit.
By providing the fin-shaped blades 27 on the rotating rotor 6, an air flow is generated, so that not only natural convection but also forced convection can be used to efficiently waste heat of the electrical unit 15.

(Regarding Frame Configuration) As shown in FIG. 2, the frame of the laser beam printer according to the present embodiment includes conductive frames 20 and 21 as a pair of left and right conductive side walls, sheet feeding means, A transfer plate 22 made of resin for holding the transfer unit, the transfer unit and the fixing unit, a conductive scanner plate 23 for holding the laser scanner 5 as a light source unit, and a conductive plate for holding the electrical unit 15 and arranged at the bottom of the apparatus. Bottom plate 24.

The conductive frame 2 as the left and right side walls
Conductive materials are suitable for 0 and 21 from the viewpoint of rigidity, electric grounding and electromagnetic wave shielding. In the present embodiment, the conductive frames 20 and 21 are made of sheet metal. As described above, the motor 16 as the driving source is directly mounted on the left conductive frame 20, and significant advantages can be obtained from heat dissipation, vibration reduction, and ease of electric ground connection.

The transport plate 22 having a portion for holding main units such as a paper feed unit, a transport unit, a transfer unit, and a fixing unit and a guide unit for the recording material P can be reduced in cost by making a complicated shape into one part. Since it has the advantage of being able to block heat radiation from the electrical component 15,
As the transfer plate 22, an integrally molded product made of a resin material is used.

The scanner plate 23 needs to have high rigidity in order to reduce the vibration caused by the rotation of the polygon mirror 5a, and is made of a sheet metal material.

For the bottom plate 24 disposed at the lowermost part of the apparatus, a sheet metal material is used in view of the rigidity as a part of the structure and the characteristics of the electromagnetic wave shield required for holding the electrical component 15.

By adopting the above-described frame configuration, it is possible to achieve low cost while satisfying the functions of heat insulation, high rigidity, heat radiation and vibration reduction.

Further, as shown in FIGS. 3 and 5, by changing the angles of the sheet feeding cassette 1 and the sheet discharging tray 14, the footprint can be reduced and the discharged recording material P can be easily seen. Various configurations are possible depending on the purpose such as. Also in this case, it is needless to say that the effect obtained by carrying the recording material P obliquely upward from the sheet feeding unit to the transfer unit to the fixing unit is the same as that described above.

[0054]

As is apparent from the above description, claim 1
According to the invention described in (2), since the heat generated from the driving means is effectively transmitted to the conductive side wall, the temperature rise in the apparatus is suppressed, and a good image can be obtained over a long period of time. . Further, since the amplitude of the vibration of the driving means is suppressed to be small by the housing having the large mass, the level of the vibration itself is reduced, and the noise of the image forming apparatus can be reduced.
Further, since the driving unit is disposed below the recording material conveyance path, it is possible to obtain an image forming apparatus capable of coping with high speed and having a high degree of design freedom.

According to the third aspect of the present invention, the air flow can be generated in the space below the recording material conveyance path by the rotating blades, and the heat generated from the electrical unit is effectively convected. The temperature rise inside the machine can be suppressed.

According to the fourth aspect of the present invention, since the driving means disposed below the recording material conveyance path is constituted by a DC motor or a stepping motor, it is possible to cope with a high speed and to form an image with a high degree of design freedom. A device can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of an image forming apparatus according to the present invention.

FIG. 2 is a perspective view of a main part of the image forming apparatus according to the present invention.

FIG. 3 is a sectional view of an image forming apparatus according to another embodiment of the present invention.

FIG. 4 is a perspective view of a main part of an image forming apparatus according to another embodiment of the present invention.

FIG. 5 is a sectional view of an image forming apparatus according to another embodiment of the present invention.

FIG. 6 is a sectional view of a conventional image forming apparatus.

FIG. 7 is a sectional view of a conventional image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper cassette (paper supply means) 2 Paper supply roller (paper supply means) 3a, 3b Conveyance roller (conveyance means) 5 Laser scanner (light source means) 7 Process cartridge (image forming means) 8 Photoconductor (image carrier) 9 Transfer Roller (Transfer Unit) 11 Fixing Unit (Fixing Unit) 16 Motor (Drive Unit) 17 Developing Unit (Developing Unit) 20, 21 Conductive Frame (Housing: Conductive Side Wall) 27 Blade P Recording Material

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hidenobu Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (Reference) 2H071 BA04 BA13 CA03 DA02 DA08 DA09 DA12 DA15 DA23 DA26 DA27 EA00 EA04 EA14

Claims (4)

[Claims] An image forming unit including at least an image carrier and a developing unit; a light source for exposing the image carrier on the image carrier; A transfer unit for transferring the visible image, a driving unit for driving the paper feeding unit, the conveying unit, and the image forming unit, and a fixing unit for heating and fixing the visible image on the recording material,
In an image forming apparatus in which the sheet feeding unit, the transfer unit, and the fixing unit are arranged obliquely upward so that the fixing unit is at the uppermost position, the driving unit records on the sheet feeding unit, the transfer unit, and the fixing unit. An image forming apparatus, which is disposed below a transport path for transporting a material. 2. The image forming apparatus according to claim 1, wherein the driving unit is directly held inside a conductive side wall constituting a housing. 3. The image forming apparatus according to claim 1, wherein fin-shaped blades are provided on a rotor rotated by said driving means. 4. An image forming apparatus according to claim 1, wherein said driving means comprises a DC motor or a stepping motor.