JP2001242672A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device of high image quality where the device can be made small with a simple constitution and a good image quality can be maintained over a long period of time by keeping down influence due to heat generated in a fuser. SOLUTION: In the device, a recording material carrying path is installed with the fuser 11 in an uppermost part and inclined in an approximate straight line from a paper feeding roll 2 to the fuser 11 and an incident angle of exposure from a laser scanner 5 to the photoreceptor 8 is made to be approximately orthogonal to the recording material carrying path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine having a function of forming an image on a recording medium such as a sheet.
The present invention relates to an image forming apparatus such as a printer or a facsimile machine.

[0002]

2. Description of the Related Art Conventionally, as this type of image forming apparatus,
For example, a laser beam printer, a copying machine, or the like that employs an electrophotographic method or another recording method is included. A laser beam printer will be described as an example. 7 and 8 are schematic views of a conventional laser beam printer.

As shown in FIGS. 7 and 8, the structure of this type of image forming apparatus is such that a recording material is conveyed from a sheet feeding unit to a transfer unit to a fixing unit substantially horizontally or substantially vertically in the image forming apparatus. Has been transported to.

For example, as shown in FIG. 7, a paper feeding means 72 is arranged at the right end of the image forming apparatus, a transfer means 79 is arranged at the center, and a fixing means 71 is arranged substantially horizontally at the left end. An image forming unit 77 such as a process cartridge and an exposing unit 75 such as a laser scanner are arranged to feed a recording material.
A configuration for transferring a toner image to a recording material and performing heat fixing of the toner image on the recording material is widely known.

As shown in FIG. 8, a sheet feeding means 82 is provided at the lower end of the image forming apparatus, a transfer means 89 is provided at the center, and a fixing means 81 is provided substantially vertically at the upper end. A configuration is also used in which an image forming unit 87 such as a process cartridge and an exposure unit 85 such as a laser scanner are arranged to feed a recording material, transfer a toner image to the recording material, and heat and fix a toner image on the recording material. ing.

[0006]

However, in the case of the above-described prior art, the following problems have occurred.

As shown in FIG. 7, in an apparatus which conveys a recording material substantially horizontally, a process cartridge and an exposing means 75 are arranged above a fixing device 71 which is a heat source. Problems such as solidification of the toner in the process cartridge and a change in the refractive index of the optical lens in the exposure unit 75 occurred, and as a result, a good output image could not be obtained.

Further, in the case of an apparatus configuration for conveying a recording material substantially vertically as shown in FIG. 8, the mounting angle of the exposure means (laser scanner) 85 is further increased (the rotation direction of the scanner motor becomes vertical). Therefore, the load on the bearing of the scanner motor is increased, and there is a problem that the life of the scanner motor is shortened due to the shaving of the bearing.

In order to solve the above-mentioned problems, the size of the entire apparatus is increased to move the fixing device, which is a heat source, away from the process cartridge and the exposure means, or to arrange the exposure means as horizontally as possible. I was going to.

However, these measures lead to an increase in the size of the apparatus and an increase in manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to make it possible to reduce the size of an apparatus with a simple structure and to reduce the influence of heat generated from a fixing unit. An object of the present invention is to provide a high-quality image forming apparatus capable of maintaining good image quality for a long period of time while suppressing image quality.

[0012]

According to the present invention, there is provided an exposure apparatus for exposing an image carrier to form an electrostatic latent image on the image carrier. Developing means for developing the electrostatic latent image formed on the carrier,
Transfer means for transferring the toner image on the image carrier developed by the developing means to a recording material fed along a recording material conveyance path by a feeding means, and a toner image transferred to the recording material And a fixing unit for fixing the recording material, wherein the recording material transport path is disposed obliquely on a substantially straight line from the feeding unit to the fixing unit with the fixing unit at the top, and The incident angle of exposure from the exposure unit to the image carrier is substantially orthogonal to the recording material transport path.

Exposure means for exposing the image carrier to form an electrostatic latent image on the image carrier; developing means for developing the electrostatic latent image formed on the image carrier; The toner image on the image carrier developed by the means,
An image forming apparatus comprising: a transfer unit configured to transfer a recording material fed along a recording material conveyance path by a feeding unit; and a fixing unit configured to fix a toner image transferred to the recording material. The feeding means, the transfer means and the fixing means are disposed within a range of 135 ± 15 ° from a horizontal plane with the fixing means as the uppermost part, and the angle of exposure from the exposure means to the image carrier is 45 ° from the horizontal plane. It is characterized in that it is set within a range of ± 15 °.

The recording material conveyance path from the fixing means to the feeding means has a first corner formed by an upper surface of the apparatus main body and a first side wall located forward in the recording material conveyance direction, and a bottom surface of the apparatus main body. It is also preferable that the first side wall is disposed so as to be substantially parallel to or substantially coincident with a surface formed by a second corner formed by a second side wall facing the first side wall.

It is also preferable that the exposure means is disposed near a third corner formed by the upper surface of the apparatus main body and the second side wall.

The exposing means includes a light source and a reflecting portion for reflecting a light beam scanned from the light source, and the light beam scanned by the exposing means may be directly incident on the image carrier from the reflecting portion. It is suitable.

[0017]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, the shape, and the relative arrangement thereof should be appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions, and are not intended to limit the scope of the invention to the following embodiments.

(Embodiment 1) As an image forming apparatus according to Embodiment 1 of the present invention, a laser beam printer adopting an electrophotographic system for scanning and recording a laser beam on a photosensitive member will be described as an example. FIG. 1 is a schematic sectional view of the image forming apparatus according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 1 denotes a paper cassette which is detachable from the image forming apparatus.
Is loaded. The recording material P is separated and fed one by one by a paper feed roller 2 as a feeding means disposed on the upper front end side of the paper 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 means, and starts drawing an image from a predetermined position on the recording material P. Reference numeral 6 denotes a folding mirror.

Reference numeral 7 denotes a process cartridge comprising a photosensitive member 8 as an image carrier and developing means, image forming means such as a cleaner and a charging roller, and 9 a recording material for displaying a visible image (toner image) on the photosensitive member 8. A transfer roller 10 serving as a transfer unit for transferring the image on P is a conveyance guide for guiding the recording material P after transfer to a fixing unit 11 serving as a fixing unit. The fixing unit 11 heats and fixes a visible image on the recording material P. I do. Then, the recording material P is discharged by a discharge roller 12 onto a discharge tray 14 formed integrally with the outer cover 13.

Next, the conveying angle of the recording material will be described.

As shown in FIG. 1, a paper feed roller 2, a transfer roller 9 for transferring a visible image on a photosensitive member 8 onto a recording material P, and a fixing device 11 for heating and fixing a toner image on the recording material P.
Are arranged diagonally upward substantially in a straight line with the fixing device 11 as the uppermost part.

After the recording material P loaded in the paper cassette 1 is fed by the paper feed roller 2, it is conveyed to the transfer section by the conveyance roller 3 along the substantially straight recording material conveyance path, and then transferred to the photosensitive member 8 The roller 9 nips and conveys the toner image to the fixing device 11 simultaneously with the transfer of the toner image.

Since the recording material conveying path of the recording material P during this period is substantially straight, the sliding noise between the recording material P and the guide member during recording material conveyance can be reduced, and the recording material P can be stably conveyed. As a result, 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. The louver portion (not shown) is discharged outside the apparatus.

Further, since the process cartridge 7 and the laser scanner 5 are disposed below or beside the fixing unit 11, a good output image can be always obtained without being affected by the heat generated from the fixing unit 11. Becomes possible.

The paper feed roller 2, the transfer roller 9 and the fixing device 11 are 135 mm from a horizontal plane with the fixing device 11 being the uppermost portion.
It is also preferred that they are arranged in a range of ± 15 °.

Further, the recording material conveying path of the present embodiment is substantially parallel to a diagonal line of the image forming apparatus (a diagonal line in the apparatus main body shown in a sectional view, a surface formed by the first corner and the second corner). Or, by matching, various mechanisms can be effectively arranged, and the size of the device can be reduced.

Next, the arrangement of the laser scanner will be described.

As shown in FIGS. 1 and 3, the unit arrangement of the laser scanner 5 is ascending to the right or to the left from the scanner polygon 5a as a reflection unit.

Here, in order to make the size of the image forming apparatus as small as possible, as shown in FIGS. 1 and 3, the recording material conveying path from the sheet feeding means to the transfer means to the fixing means is substantially moved. It is most effective to make a laser beam (light beam scanned from a light source) incident on the photoconductor 8 from a vertical direction.

With this configuration, the depth and height of the image forming apparatus can be reduced to minimum dimensions. Further, the scanner motor 5b for rotating the scanner polygon 5a can be arranged in a substantially horizontal state, the load on the bearing of the scanner motor 5b is eliminated, and the life of the scanner motor 5b is shortened due to the shaving of the bearing. It can be used for a long period of time without producing.

Further, the paper feed roller 2, the transfer roller 9 and the fixing device 11 are fixed to the fixing device 11 at an uppermost position from a horizontal plane by 135 degrees.
When installed in the range of ± 15 °, laser scanner 5
It is also preferable that the incident angle at which the laser beam is incident on the photosensitive member 8 be set within a range of 45 ± 15 ° from the horizontal plane.

With the configuration shown in FIG. 1, the process cartridge 7 can be attached and detached substantially horizontally in the direction of the paper cassette 1, and jam processing and replacement of the process cartridge 7 in the image forming apparatus can all be performed from the same direction. Can be performed, and usability can be improved.

In the case of the configuration shown in FIG. 3, the mounting and dismounting of the process cartridge 7 is performed from above.
Since the laser scanner 5 can be moved away from the fixing device 11, there is an advantage that the influence of the temperature rise due to the heat of the fixing device 11 can be reduced.

As described above, if the setting of the incident angle of the laser beam is configured as in the present embodiment, a large degree of freedom can be given to the arrangement of the laser scanner 5, so that the problems of usability and temperature rise are reduced. It is easy to avoid.

Next, the layout of the electrical system will be described.

As shown in FIG. 1, an electrical unit 15 composed of an AC power supply, a DC power supply, and a high-voltage power supply is disposed below a recording material conveying path extending obliquely upward from a sheet feeding unit to a fixing unit. Is increased from the sheet feeding section to the fixing section.

In this manner, a path for an air flow generated by the heat generated from the electrical component 15 is 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 outer cover 13.
At this time, by providing a space between the rear surface of the fixing device 11 and the exterior cover 13, it is possible to generate an air flow due to waste heat of the fixing device 11 in this portion as well.

Accordingly, as described above, a large space is provided below the fixing unit 11 and the electric unit 15 is disposed, and the space is provided on the rear side of the fixing unit 11 so that the electric unit can be provided even if there is no FAN for cooling. An airflow for waste heat from the section 15 to the fixing device 11 can be generated, so that there is an effect that heat buildup inside the image forming apparatus is eliminated and a temperature rise can be prevented.

As a result, it becomes possible to achieve a cost-reduction by the FAN-less structure, and also to eliminate the noise generated from the FAN, thereby providing a quiet image forming apparatus.

In order to effectively use the lower space area of the recording material transporting path extending obliquely upward from the sheet feeding means to the fixing means, the electrical unit 15 has an L-shaped layout comprising a horizontal part and a vertical part. By doing so, the efficiency of the electrical component can be further increased.

More specifically, a component or element that is a heat source is arranged on the vertical surface side, and a component or element that does not generate heat relatively is arranged on the horizontal plane side. By laying out in this manner, it is possible to more efficiently perform the waste heat from the electrical unit 15.

Next, the arrangement of the driving sources will be described.

As shown in FIGS. 1 and 2, a motor 16 as a drive source is directly mounted on a conductive side wall which is a part of a frame of the image forming apparatus, and is provided below a recording material conveying surface. Are located.

By arranging it below the recording material transport section,
When responding to an increase in the speed of the image forming apparatus, it is possible to flexibly cope with an increase in the size of the motor or a change from a stepping motor to a DC motor. by this,
For example, it is possible to easily achieve a speed increase from 10 ppm to 20 ppm.

Further, by directly mounting the motor 16 on the conductive frame of the image forming apparatus, the heat generated by the motor itself can be easily released to the frame, and the motor efficiency can be improved. Also, it is easy to take the ground and the total cost can be reduced.

Further, both the motor 16 and the electrical unit 15 are arranged below the recording material transporting unit, and the blades are provided on the shaft of the motor 16 to generate an air flow, thereby more efficiently reducing the waste heat of the electrical unit 15. Can be performed.

Next, the frame configuration will be described.

As shown in FIG. 2, the frame structure of the present embodiment comprises a pair of conductive left and right side walls 20 and 21 and a paper feed unit, a transfer unit, a transfer unit and a fixing unit. It comprises a plate 22, a conductive scanner plate 23 for holding the laser scanner 5 as an exposure means, and a conductive bottom plate 24 for holding the electrical component 15 and 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 which is a driving source is directly mounted on the left side wall 20, and heat radiation,
Significant advantages are obtained from 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 reduce costs by making a complicated shape into one part. Since there is a merit that heat radiation from the electrical unit 15 can be insulated, an integrally molded product 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 scanner polygon 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 because of the rigidity as a part of the structure and the characteristics of the electromagnetic wave shield required to hold the electrical component 15.

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.

Further, by changing the angles of the paper cassette 1 and the paper discharge tray 14 as shown in FIGS. 3 and 4, the footprint can be reduced, and the discharged recording material P can be easily seen. Various configurations are possible depending on the purpose.

Of course, even in this case, the effect obtained by carrying the recording material P obliquely upward from the sheet feeding means to the transfer means to the fixing means is equivalent.

(Embodiment 2) Next, an image forming apparatus according to Embodiment 2 of the present invention will be described. FIG. 5 is a schematic cross-sectional view of an image forming apparatus according to the second embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the image forming apparatus shown in FIG. 5, the scanner polygon 5a in the laser scanner 55 is disposed on the front side of the main body (right side, third corner in the drawing), and the laser light emitted from the laser diode (not shown) After passing through the scanner polygon 5a and the folding mirror 6, the photosensitive member 8
Is incident on. This angle of incidence is the same as in the first embodiment,
The direction is substantially perpendicular to the recording material conveyance path from the sheet feeding unit to the transfer unit to the fixing unit.

With such an arrangement, the sheet feeding means, the fixing means, and the exposure means are dispersedly arranged at diagonal positions of the image forming apparatus, so that the entire apparatus can be used effectively, and The depth and height of the forming apparatus can be reduced to minimum dimensions.

In the laser scanner 55 shown in FIG. 5, the scanner polygon 5a is disposed at a symmetrical position with respect to the fixing unit 11, which is a heat source. it can.

(Embodiment 3) Next, an image forming apparatus according to Embodiment 3 of the present invention will be described. FIG. 6 is a schematic cross-sectional view of the image forming apparatus according to the third embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the image forming apparatus shown in FIG. 6, the scanner polygon 5a in the laser scanner 65 is arranged on the front side (right side in the drawing) of the main body, and the laser beam scanned from the scanner polygon 5a is directly incident on the photosensitive member 8. You.

This incident angle is, as in the first embodiment, substantially perpendicular to the recording material transport path from the sheet feeding means to the transfer means to the fixing means.

Also in this arrangement, the paper feeding means, the fixing means, and the exposure means are dispersedly arranged at diagonal positions of the image forming apparatus, so that the entire apparatus can be used effectively. The depth and height of the image forming apparatus can be reduced to minimum dimensions.

Further, in the laser scanner 65 shown in FIG. 6, since the scanner polygon 5a is disposed at a position symmetrical to the fixing device 11, which is a heat source, there is almost no influence by the heat source, and the life of the scanner motor 5b is extended. it can.

In this embodiment, the scanner polygon 5a
The laser light scanned from is directly incident on the photoreceptor 8,
Since the folding mirror 6 does not exist between the scanner polygon 5a and the photoconductor 8, the number of components can be reduced, and the mirror adjustment step can be omitted, so that a significant cost reduction can be achieved.

[0070]

As described above, according to the present invention,
The recording material transport path is disposed obliquely on a substantially straight line from the feeding means to the fixing means with the fixing means as the uppermost part, and the exposure incident angle from the exposure means to the image carrier is set with respect to the recording material transport path. Since they are substantially orthogonal, a high-quality image forming apparatus that can reduce the size of the apparatus with a simple configuration, suppress the influence of heat generated from the fixing unit, and maintain good image quality over a long period of time Can be provided.

Further, since the influence of the heat of the fixing means on the exposure means can be suppressed and various devices can be effectively disposed, the scanner motor provided in the exposure means can be disposed substantially horizontally, Can be extended.

The light beam scanned by the exposure means is
By directly entering the image carrier from the reflecting section, the folding mirror can be eliminated, so that the number of components can be reduced, the mirror adjustment process can be omitted, and the cost can be significantly reduced. It becomes possible.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of a main part of the image forming apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a schematic sectional view of the image forming apparatus according to Embodiment 1 of the present invention.

FIG. 4 is a schematic sectional view of the image forming apparatus according to Embodiment 1 of the present invention.

FIG. 5 is a schematic sectional view of an image forming apparatus according to Embodiment 2 of the present invention.

FIG. 6 is a schematic sectional view of an image forming apparatus according to Embodiment 3 of the present invention.

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

FIG. 8 is a schematic sectional view of a conventional image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper cassette 2 Feed roller 3a, 3b Transport roller 4 Registration sensor 5 Laser scanner 5a Scanner polygon 5b Scanner motor 6 Folding mirror 7 Process cartridge 8 Photoconductor 9 Transfer roller 10 Transport guide 11 Fixing device 12 Discharge roller 13 Exterior cover 14 Paper discharge tray 15 Electrical unit 16 Motor 20, 21 Side wall 22 Transport plate 23 Scanner plate 24 Bottom plate

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C362 BA87 BA90 CB80 DA04 2H071 DA02 DA12 DA23 EA04 2H076 AB12 AB18 EA16 5C062 AA05 AB08 AB32 AD06 BA01 5C074 AA02 AA11 BB03 BB26 CC26 GG04 GG12 GG15 HH02

Claims (5)

[Claims] An exposure unit configured to form an electrostatic latent image on the image carrier by exposing the image carrier; a developing unit configured to develop the electrostatic latent image formed on the image carrier; Transfer means for transferring the toner image on the image carrier developed by the developing means to a recording material fed along a recording material conveyance path by a feeding means; and a toner image transferred to the recording material. A fixing unit for fixing the recording material, wherein the recording material transport path is disposed obliquely on a substantially straight line from the feeding unit to the fixing unit with the fixing unit as an uppermost part, An image forming apparatus, wherein an incident angle of exposure from the exposure unit to the image carrier is substantially orthogonal to the recording material conveyance path. 2. An exposure device for forming an electrostatic latent image on the image carrier by exposing the image carrier, a developing device for developing the electrostatic latent image formed on the image carrier, Transfer means for transferring the toner image on the image carrier developed by the developing means to a recording material fed along a recording material conveyance path by a feeding means; and a toner image transferred to the recording material. A fixing unit for fixing the fixing unit, wherein the feeding unit, the transfer unit, and the fixing unit are disposed in a range of 135 ± 15 ° from a horizontal plane with the fixing unit as an uppermost part; An image forming apparatus wherein an incident angle of exposure from an exposure unit to the image carrier is set within a range of 45 ± 15 ° from a horizontal plane. 3. A recording material conveying path from the fixing unit to the feeding unit includes a first corner formed by an upper surface of the apparatus main body and a first side wall positioned forward in a recording material conveying direction; A second side wall formed by the bottom surface and a second side wall facing the first side wall;
The image forming apparatus according to claim 1, wherein the image forming apparatus is disposed so as to be substantially parallel or substantially coincident with a surface formed by the corners of the image forming apparatus. 4. An image according to claim 1, wherein said exposure means is arranged near a third corner formed by an upper surface of the apparatus main body and said second side wall. Forming equipment. 5. The light exposure unit includes a light source and a reflection unit that reflects a light beam scanned from the light source, and the light beam scanned by the exposure unit is directly incident on the image carrier from the reflection unit. The image forming apparatus according to claim 1, 2, 3, or 4, wherein