JP2001092205A - Image forming device - Google Patents

Abstract

(57) [Summary] [Object] To provide a quiet, high-quality, small-sized image forming apparatus that does not have a temperature rise in the apparatus. A recording material transport path for transporting a recording material from a lower paper feed roller 2 to a fixing device 11 via a transfer unit is formed obliquely upward with the fixing device 11 as an uppermost portion. The electrical component 15 is disposed below the device, and the heat-generating component of the electrical component 15 is disposed on the rear side of the apparatus.

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 As an image forming apparatus, there are a laser beam printer, a copying machine and the like which employ an electrophotographic system and other recording systems. Hereinafter, a laser beam printer will be described as an example of an image forming apparatus. I do.

FIG. 6 shows an example of a conventional laser beam printer.
This will be described with reference to FIG.

In this laser beam printer, a paper feed tray 1 serving as a paper feeding means for stacking a plurality of recording materials P such as recording paper is provided on the back side (right side in the figure) and near side (left side in the figure) of the printer body. A paper discharge tray 14 serving as a paper discharge means for stacking printed recording materials is disposed in a vertically inclined state, and a process cartridge 7 and an exposure means are provided between the paper supply tray 1 and the paper discharge tray 14. A laser scanner 5 is disposed, and a fixing device 12 is disposed on the left end side.

The recording material P fed from the paper feed tray 1 by the paper feed roller 2 arranged near the lower end of the paper feed tray 1 is transferred by the transfer rollers 9a by the transport rollers 3a and 3b.
Is transferred to a transfer section where the toner image on the photosensitive drum 8 is transferred, and the transferred recording material is further transferred to the fixing device 11. After the unfixed toner image is fixed, the sheet is discharged to the discharge tray 14 by the discharge roller 12. Paper. Reference numeral 4 denotes a registration sensor which synchronizes the leading end position of the recording material P with the light emission timing of the laser scanner 5 as an exposure light source, and draws an image from a predetermined position on the recording material P.

In this printer, a transport path for transporting the recording material fed from the paper feed roller 2 to the fixing device 11 via the transfer unit is disposed substantially horizontally, and an electrical unit 15 is disposed below the horizontal transport path. Then, the process cartridge 7 is disposed above the substantially horizontal recording material conveyance path, and the laser scanner 5 is disposed thereon.

In the printer shown in FIG. 7, the paper feed tray 1 is disposed at the lower end and the paper discharge tray 14 is disposed substantially horizontally at the upper end.
1 is arranged on the conveyance path substantially vertically, and the electrical component 15
The fixing device 11 is disposed substantially vertically on the upper side of the printer main body, as shown in FIG.
A process cartridge 7 as an image forming unit and a laser scanner 5 as a light source unit are provided on the side surface of the vertical recording material conveying path.
Has been arranged.

[0008]

However, in a printer having a substantially horizontal recording material conveyance path shown in FIG. 6, a process cartridge 7 and a laser scanner as exposure light source means are provided above a fixing device 11 which is a heat source. 5
Are arranged, the toner in the process cartridge 7 may be solidified due to the temperature rise in the apparatus, or the refractive index of the optical lens in the laser scanner 5 may be changed, so that a good output image cannot be obtained. There was something.

A transfer path from the paper feed tray 1 as a paper feed means to the transfer roller 9 as a transfer means, and a transfer material transport from a fixing device 11 as a fixing means to a paper discharge tray 14 as a paper discharge means. Since the path requires a large change in direction, the sound of the back end of the transfer material jumping and the sound of the transfer material rubbing against the transfer surface during the change of direction are large, and the operating noise of the image forming apparatus in actual use is increased. Had been lost.

Further, the trailing edge of the transfer material comes off from the paper feed tray 1 as the paper feed means, and the vibration when the direction is changed is transmitted to the transfer material. There is also a problem that the image is disturbed when the toner image is transferred to the toner image.

In the case of a printer having a vertical recording material transport path for transporting a recording material substantially vertically as shown in FIG. 7, the problem of operating noise and the problem of image disturbance are similar.

Further, in this case, the mounting angle of the laser scanner 5 as the exposure light source means is further increased, so that the rotation axis of the polygon mirror 5a becomes close to horizontal, and the rotation of the polygon mirror 5a becomes a bearing of a scanner motor for driving the polygon mirror 5a. There is also a problem that the load is increased and the life of the scanner motor is shortened due to shaving of the bearing.

Therefore, conventionally, in order to solve the above-described problems, the size of the entire apparatus is increased to move the fixing device 11 which is a heat source away from the process cartridge 7 and the laser scanner 5 as an exposure light source. Measures have been taken to minimize the rate of change of the transport path and to arrange the exposure light source means as close to horizontal as possible. However, as a result of these countermeasures, the apparatus has been increased in size and the manufacturing cost has been increased.

An object of the invention according to the present invention is to solve the above-mentioned problem, and to provide a quiet, high-quality, small-sized image forming apparatus which does not raise the temperature inside the apparatus.

[0015]

According to a first aspect of the present invention, a latent image formed on a latent image carrier by image light from image exposure means is visualized by a developer. Image forming means, a transfer means for transferring a visible image on the latent image carrier to a recording material at a transfer part, a fixing means for fixing the visible image on the recording material having passed through the transfer part, and a paper feeding means. In an image forming apparatus having at least a recording material transport path for transporting a recording material to the fixing unit via the transfer unit, and an electrical unit configured by electric components of the apparatus, the recording material transport path includes the fixing unit. The electrical unit is formed obliquely upward with the unit as the uppermost part, the electrical unit is arranged below the recording material transport path, and the heat-generating component of the electrical unit is arranged on the back side of the apparatus.

A second configuration for realizing the object of the invention according to the present application includes: an image forming unit that visualizes a latent image formed on a latent image carrier by image light from an image exposure unit with a developer; A transfer unit for transferring the visible image on the latent image carrier to a recording material at a transfer unit, a fixing unit for fixing the visible image on the recording material passing through the transfer unit, and a recording material from a paper feeding unit to the transfer unit The recording material transport path is configured to be conveyed to the fixing unit through the fixing unit, and an electrical unit configured by electrical components of the apparatus. Formed upward, the electrical component is disposed below the recording material transport path, the heat-generating component of the electrical component is disposed on the back side of the apparatus, and above the recording material transport path, relative to the fixing unit. At the same position in the vertical direction or Characterized in that a said image exposure means and the image forming means.

A third configuration for realizing the object of the invention according to the present application is any one of the above configurations, wherein the electrical component is disposed on at least one of the apparatus bottom face, the apparatus rear face, and the recording material transport path face. It is characterized by things.

A fourth configuration for realizing the object of the invention according to the present application is characterized in that, in any one of the above-described configurations, the primary-side components are centrally mounted on the rear surface of the device.

A fifth configuration for realizing the object of the invention according to the present application is that, in any one of the above configurations, the recording material transport path is arranged so as to be substantially parallel to a diagonal line of the image forming apparatus main body. Features.

In the above configuration, since the electrical unit is disposed below the oblique transport path including the paper feeding unit, the transfer unit, and the fixing unit, the space from the paper feeding unit to the fixing unit increases, and the space above the electrical unit is increased. Therefore, it is possible to prevent the heat generated by the electrical component from adversely affecting the light source unit and the image forming unit due to the heat insulating effect of the air layer.

Further, by arranging the heat-generating components on the electrical equipment on the rear side of the apparatus, it is possible to improve the exhaust efficiency to the rear side of the main body.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of the present invention employs an electrophotographic method in which a laser beam is scanned and recorded on a photosensitive member (photosensitive drum) as an image carrier. A laser beam printer as an image forming apparatus will be described as an example.

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

In FIG. 1, reference numeral 1 denotes a paper cassette which is detachable from the image forming apparatus main body, and a recording material P is loaded 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 feed cassette 1, and is conveyed to a transfer unit by conveyance rollers 3a and 3b.

Reference numeral 4 denotes a registration sensor, which synchronizes the leading end position of the recording material P with the light emission timing of the laser scanner 5 as an exposure light source, and draws an image from a predetermined position on the recording material P. The laser scanner 5 serving as an exposure light source is a photosensitive drum which forms a process cartridge 7 via a polygon mirror 5 a which rotates a laser (not shown) which is turned on / off in accordance with image information at a high speed by a scanner motor (not shown), and a folding mirror 6. Irradiation is performed on the drum 8 to form a latent image on the photosensitive drum 8.

The process cartridge 7 of the present embodiment includes a photosensitive drum 8, a developing device for forming a latent image on the photosensitive drum 8 with a developer to form a visible image (toner image), and a transfer device on the photosensitive drum 8 after transfer. The image forming means, such as a cleaner for cleaning the remaining toner and a charging roller for charging the photosensitive drum 8 to a uniform potential, is integrated and made replaceable.

Reference numeral 9 denotes a transfer roller for transferring the visible image on the photosensitive drum 8 onto the recording material P. Reference numeral 10 denotes a conveyance guide for guiding the transferred recording material P to the fixing device 11.
1 heat-fixes the unfixed visible image on the recording material P. Then, the recording material P is discharged by a discharge roller 12 onto a discharge tray 14 formed integrally with the outer cover 13.

(Regarding Recording Material Conveying Angle) As shown in FIG.
And a transfer unit for transferring the visible image on the photosensitive drum 8 onto the recording material P by the transfer roller 9, and a fixing device 11 for heating and fixing the toner image on the recording material P. The fixing device 11 is disposed obliquely upward on a substantially straight line with the fixing device 11 as the uppermost portion.

The recording material P loaded on the sheet cassette 1
After the paper is fed by the paper feed roller 2, the paper is conveyed to the transfer section by the conveyance rollers 3 a and 3 b along a substantially straight conveyance path, and thereafter, by the photosensitive drum 8 and the transfer roller 9.
The toner image is nipped and conveyed to the fixing device 11 simultaneously with the transfer of the toner image.

The conveying path of the recording material P during this period is substantially straight, so that the sliding noise between the recording material P and the guide member forming the recording material conveying path during the recording material conveyance can be reduced, and the recording material P can be reduced. P can be stably conveyed, and the reliability of recording material conveyance can be improved.

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

Further, since the process cartridge 7 and the laser scanner 5 are arranged below or beside the fixing device 11, a good output image is always obtained without being affected by the heat generated from the fixing device 11. It becomes possible.

Furthermore, by making the recording material conveyance path of this embodiment substantially parallel or coincident with the diagonal line of the casing of the image forming apparatus, various mechanisms can be effectively arranged, and the apparatus can be downsized. It became possible to plan.

(Laser Scanner Arrangement) As shown in FIG. 1, the laser scanner 5 is arranged as a unit arranged upward to the right from the scanner polygon mirror 5a. Here, in order to make the size of the image forming apparatus as small as possible, as shown in FIG. 1, the photosensitive drum 8 is set in a direction substantially perpendicular to the recording material conveying path from the sheet feeding means to the transfer means to the fixing means. Is most effective. With this configuration, the depth and height of the image forming apparatus can be reduced to minimum dimensions.

In the configuration shown in FIG. 1, the process cartridge 7 can be attached and detached from the rear side of the apparatus main body substantially horizontally in the direction in which the paper feed cassette 1 is pulled out. All exchanges can be performed from the same direction, and usability can be improved.

As shown in FIG. 3, the laser scanner 5 may be arranged substantially in parallel with the recording material inclined conveyance path extending from the paper feeding unit to the transfer unit to the fixing unit. In the case of (1), the process cartridge 7 is attached and detached from above, but since the laser scanner 5 can be kept away from the fixing device 11, the influence of the temperature rise due to the heat of the fixing device 11 can be reduced. There are benefits. Needless to say, the laser scanner 5 shown in FIG. 3 is configured to make the laser beam incident on the photosensitive drum 8 from a direction substantially perpendicular to the recording material conveyance path from the sheet feeding unit to the transfer unit to the fixing unit.

As described above, the setting of the laser beam incident angle in which the laser beam is incident on the photosensitive drum 8 from a direction substantially perpendicular to the recording material conveyance path from the sheet feeding means to the transfer means to the fixing means is performed in this embodiment. According to the configuration, since the laser scanner 7 has a large degree of freedom in arrangement, it is easy to avoid the problems of usability and temperature rise.

(About electrical system layout) AC input,
Low voltage power supply, high voltage power supply, actuator driver, ASI
C, a fixing drive, and an electrical unit 15 including a sensor are shown in FIG.
As shown in FIG. 2, the recording medium is disposed at a lower part of a recording material conveyance path which extends obliquely upward from the paper feeding unit to the fixing unit, and a space area in the electrical unit 15 is increased from the paper feeding unit to the fixing unit. I have. By doing so, it is possible to secure the path of the air flow generated by the heat generated from the electrical component unit 15.

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

Therefore, by providing a large space below the fixing device 11 and arranging the electrical unit 15 as described above, and by providing a space on the rear side of the fixing device 11, the F for cooling is provided.
Even if there is no AN or the like, it is possible to generate an air flow for discharging heat from the electrical unit 15 to the fixing device 11, thereby eliminating the heat buildup inside the image forming apparatus and preventing an increase in temperature. is there.

FIG. 4 shows details of the mounting arrangement of the electrical component unit 15. FIG. 4 is a view of the electrical component 15 as viewed from above. An inlet (input terminal section) and a power SW (power switch) are arranged on the right rear side to form an AC input section, and a low voltage power supply section is formed in the rear center. As a result, the heat of the low-voltage power supply can be easily exhausted from the back of the main body.

A high voltage circuit is provided on the rear left side of the main body to provide a contact for a developing device and a charging device.

An ASIC that does not generate heat is provided on the front left side.
Mount the COMS-based components centered on
An I / F with an ormator is configured.

A high voltage circuit for generating a transfer voltage to the transfer roller is disposed on the front right side.

This makes it possible to realize a fan-less (fanless) configuration, thereby not only achieving cost reduction, but also eliminating noise generated from the fan, thereby providing a quiet image forming apparatus. Becomes

That is, by arranging the heat-generating components, which are the primary components on the electrical equipment, on the rear side of the apparatus, it is possible to improve the exhaust efficiency to the rear side of the main body.

(Regarding Arrangement of Driving Source) As shown in FIGS. 1 and 2, a motor 16 as a driving source is directly mounted on a conductive side wall 20 which is a part of a frame of the image forming apparatus. It is located below the recording material transport path.

By arranging the motor 16 as a drive source at the lower part of the recording material conveyance path, it is possible to cope with an increase in the size of the motor and a change from a stepping motor to a DC motor, etc. However, it is possible to respond flexibly. As a result, it is possible to easily achieve a speed increase from, for example, 10 ppm to 20 ppm.

Further, by directly mounting the motor on the conductive frame of the image forming apparatus, the heat generated by the motor itself can be easily released to the frame.
The motor efficiency can be improved, and grounding can be easily performed, so that the total cost can be reduced.

A motor 16 is provided below the recording material transport path.
By arranging both the electrical component 15 and the wings on the motor shaft, an air flow is generated, and the heat removal operation of the electrical component 15 can be performed more efficiently.

(Regarding Frame Configuration) As shown in FIG. 2, the frame configuration of the present embodiment holds a pair of left and right conductive side walls 20, 21 and a sheet feeding unit, a conveying unit, a transfer unit, and a fixing unit. Plate 22, which is made of a resin to be formed, a conductive scanner plate 23 which holds the laser scanner 5 as a light source means, and a conductive bottom plate 24 which holds the electrical unit 15 and is arranged at the bottom of the image forming apparatus. .

The left and right side walls 20, 21 are rigid, electric ground,
A conductive material is suitable from the viewpoint of electromagnetic wave shielding, and is made of sheet metal. As described above, the motor 16 serving as the drive source is directly mounted on the left side wall 20, and significant advantages are obtained from heat dissipation, vibration reduction, and ease of electrical 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 forming a complicated shape into one part. Since there is an advantage that heat radiation from the electrical component can be insulated, 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 uses a sheet metal material.

Further, the bottom plate 2 arranged at the bottom of the apparatus
Reference numeral 4 uses a sheet metal material in view of the rigidity as a part of the structure and the characteristics of the electromagnetic wave shield required to hold the electrical components.

By adopting the above-described frame structure, there is an effect that low cost can be achieved while satisfying the functions of heat insulation, high rigidity, heat radiation and vibration reduction.

(Second Embodiment) FIG. 5 shows a second embodiment.

In the second embodiment, similarly to the modification of the first embodiment shown in FIG. 3, the laser scanner 5 as the exposure optical means is inclined from the paper feeding means to the transfer means to the fixing means. The recording paper transport path is arranged substantially parallel to the recording material transport path, and the angle between the paper feed tray (paper feed cassette) 1 and the paper discharge tray 14 is changed (substantially perpendicular to the inclined transport path) to reduce the footprint. Various configurations are possible depending on the purpose, for example, making the discharged recording paper easier to see. Even in the case of the embodiment shown in FIG. 3, the paper feed cassette 1 and the paper discharge tray 14 are both inclined from the horizontal state, so that the footprint can be reduced and the discharged recording paper can be easily seen. Is possible.

Of course, even in this case, it is needless to say that the effect obtained by carrying the recording material obliquely upward from the sheet feeding means to the transfer means to the fixing means is the same.

[0060]

As described above, according to the present invention,
An electrical unit including an AC input, a low-voltage power supply, a high-voltage power supply, an actuator driver, and an ASIC is disposed below a recording material conveyance path that extends obliquely upward from a sheet feeding unit to a fixing unit, and a space area in the electric unit is separated from the sheet feeding unit. By making the configuration larger toward the fixing unit, a path of an air flow generated by heat generated from the electrical unit is secured.

Further, by arranging the AC input and the low-voltage power supply on the back of the main body, the exhaust efficiency is greatly improved. Functions and performance can be easily improved without making significant changes to the configuration.

Further, the size of the image forming apparatus can be reduced by arranging the recording material conveying path from the sheet feeding means to the transfer means to the fixing means on a line substantially parallel to the diagonal line of the image forming apparatus. .

Further, since the image forming means and the image exposing means are arranged laterally or below the fixing means,
The image forming unit and the image exposing unit are not affected by the heat of the fixing unit.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of a frame of the image forming apparatus of FIG. 1;

FIG. 3 is a sectional view of an image forming apparatus showing a modification of the first embodiment of FIG. 1;

FIG. 4 is a plan view of an electrical unit according to the first embodiment.

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

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

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Paper feed cassette 2 ... Paper feed roller 3a ... Transport roller 3b ... Transport roller 4 ... Registration sensor 5 ... Laser scanner 5a ... Polygon mirror 6 ... Folding mirror 7 ... Process cartridge 8 ... Photoconductor 9 ... Transfer roller 10 ... Transport guide DESCRIPTION OF SYMBOLS 11 ... Fixing device 12 ... Discharge roller 13 ... Outer cover 14 ... Discharge tray 15 ... Electrical part 16 ... Motor 20 ... Left side plate 21 ... Right side plate 22 ... Transport plate 23 ... Scanner plate 24 ... Bottom plate

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Susumu Ikuma 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H071 DA08 DA09 DA12 DA15 DA21 DA23 EA00 EA04 EA14

Claims (5)

[Claims] An image forming means for developing a latent image formed on the latent image carrier by image light from an image exposing means with a developer; and recording a visible image on the latent image carrier at a transfer section. Transfer means for transferring to a material, a fixing means for fixing a visible image on a recording material having passed through a transfer unit, a recording material transport path for transporting a recording material from a paper feeding means to the fixing means via the transfer unit,
An image forming apparatus having at least an electrical component unit configured by electrical components of the apparatus, wherein the recording material transport path is formed obliquely upward with the fixing unit as an uppermost part, and below the recording material transport path. An image forming apparatus, wherein the electric component is disposed on a rear side of the apparatus. 2. An image forming means for visualizing a latent image formed on a latent image carrier by image light from an image exposing means with a developer, and recording a visible image on the latent image carrier at a transfer unit. Transfer means for transferring to a material, a fixing means for fixing a visible image on a recording material having passed through a transfer unit, a recording material transport path for transporting a recording material from a paper feeding means to the fixing means via the transfer unit,
An image forming apparatus having at least an electrical component unit configured by electrical components of the apparatus, wherein the recording material transport path is formed obliquely upward with the fixing unit as an uppermost part, and below the recording material transport path. The heating unit of the electrical unit is disposed on the back side of the apparatus, and the image forming unit is arranged at the same position or lower than the fixing unit in the vertical direction above the recording material conveyance path. And an image exposing unit. 3. The image forming apparatus according to claim 1, wherein the electrical unit is disposed on at least one of a bottom surface of the apparatus, a rear surface of the apparatus, and a surface of the recording material conveyance path. 4. The image forming apparatus according to claim 1, wherein the primary-side components are centrally mounted on a rear surface of the apparatus. 5. The image forming apparatus according to claim 1, wherein the recording material conveyance path is arranged so as to be substantially parallel to a diagonal line of the image forming apparatus main body.