JPH0566621A - Image forming device - Google Patents

Abstract

PURPOSE:To provide the image forming device where each unit can be positioned to each other with high precision, rigidity of a frame can be fortified, and image quality and reliability can be improved. CONSTITUTION:A wall part provided with plane shaped parts in parallel to each other and a connector connecting the wall parts to each other are provided in the image forming device. Then, a structure frame 2 of the device main body 1 is provided consisting of these wall parts and the connector part formed by an integral formation method utilizing resin is provided. The image forming means, a feeding means and a carrying means of a transfer material P, a transferring means, and a fixing means are attached to the structure frame 2. Therefore, since almost all units necessary for the image forming device adapting an electrophotographic method are positioned and assembled to one structure frame 2, each unit is positioned with high precision, and alignment can be carried out well. Furthermore, the rigidity of the structure frame 2 can be maintained well, oscillation of each unit attached to this can be controlled, and the image quality can be maintained at a high level.

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 adopting an electrophotographic system, and more particularly to an image forming apparatus such as an electrophotographic printer or a facsimile machine using a laser beam or an LED array as a light source.

[0002]

2. Description of the Related Art As one of the structural forms of an image forming apparatus of this type, there is one in which the apparatus is divided into an upper housing and a lower housing, and the upper housing can be freely opened and closed around a hinge with respect to a lower housing. .. According to this, for example, as shown in FIG.
Paper feed means a, transfer means b, transfer material conveying means c, driving means, fixing means d, etc. on the lower housing A side, and process cartridge (image forming means) 7 and its guide holding on the upper housing B side. Means, an optical system means (exposure light source means such as a laser scanner) e, a discharging means f, etc. are incorporated respectively, and the upper housing B side is opened and raised around the hinge 30.
The process cartridge 7 is attached and detached, and the transfer material is jammed.

However, in such an apparatus, since the upper housing and the lower housing of the apparatus are configured independently of each other, it is difficult to obtain positional accuracy or alignment (parallelism) between components or units. was there. Particularly, in the transfer portion, the positions of the images on the recording material and the photoconductor may be twisted, displaced, or tilted.

Further, since it is difficult to obtain the positional accuracy between the drive member for receiving the drive of the photosensitive member in the process cartridge loaded in the main body of the apparatus and the gear of the drive means on the lower housing side, the axial distance between the gears is deviated. As a result of unevenness in the rotation speed of the photoconductor, pitch unevenness (a phenomenon in which the spacing between the scanning lines scanned on the photoconductor becomes uneven) also occurs in the image.

Further, in the case where the frame of the main body of the apparatus is constituted by the side plates made of sheet metal facing each other and connected by the metal stays made of separate members, the side plates are twisted or tilted. It is difficult to improve the accuracy of the frame, and the sheet metal frame resonates due to the vibration caused by the drive system, which may cause an image defect such as an unclear image.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to position each unit with high accuracy and to increase the rigidity of a frame. An object of the present invention is to provide an image forming apparatus capable of improving image quality and reliability.

Another object of the present invention is to reduce the size of the main body of the apparatus and to save the resources of the constituent members and the installation area.

Still another object of the present invention is to provide a process cartridge loading structure that is compatible with miniaturization of the apparatus main body.

[0009]

[Means for Solving the Problems] In order to achieve the above object,
According to the present invention, in an image forming apparatus, an image forming means for forming a developed image on an electrophotographic photosensitive member, a transfer material feeding means, a transfer material conveying means, a transfer means, and a fixing means are arranged in parallel with each other. A structural frame of an apparatus main body having a pair of wall portions having planar portions and a connecting portion for connecting the wall portions to each other, and these wall portions and the connecting portions are configured by an integral molding method using resin. And the image forming means, the feeding means, and
It is characterized in that a conveying means, a transfer means and a fixing means are attached.

Further, according to the present invention, an image forming apparatus is detachably attached to an apparatus main body, and an electrophotographic photosensitive member and at least one process means acting on the photosensitive member for forming an image are integrally formed. A process cartridge, a transfer material feeding means, a transfer material conveying means, a transfer means, a fixing means, and a structural frame of an apparatus main body including a wall portion having plane portions parallel to each other, Loading of the process cartridge into the apparatus main body is performed by guiding the convex portion of the process cartridge into a groove portion that is provided in the structural frame and draws a curve toward a predetermined mounting position. What is done is the feature.

[0011]

According to the present invention, almost all the units from the feeding to the discharging of the transfer material necessary for the image forming apparatus employing the electrophotographic system are positioned and assembled on one structural frame. Each unit is positioned with high precision and can be well aligned. Further, the rigidity of the structural frame is kept high, the vibration of each unit attached thereto is suppressed, and the image quality is kept high.

Further, by forming the guide portion, which is the transfer material guide, integrally with the structural frame, the positional relationship between the transfer material and the photoconductor during transfer can be maintained with high precision, and image misalignment during transfer can be prevented. To be done. Further, since the positional accuracy of the fixing unit and the guide portion after fixing is kept high, the risk of the transfer material jamming after fixing is reduced.

Furthermore, when the process cartridge is loaded into the apparatus main body, the groove is provided in the structural frame,
Since the process cartridge is guided by the convex portion of the process cartridge, the process cartridge is accurately positioned in the apparatus main body, and the positional relationship between the process cartridge and other units attached to the structural frame is high. Maintained in precision.

[0014]

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

FIG. 1 is a side sectional view of a laser beam printer. In FIG. 1, 11 is a photosensitive drum 10, which is an electrophotographic photosensitive member, a charging device 101, a developing device 102, and a cleaning device 103, as shown in FIG. And the like, and the process cartridge 1
1, the first conveyance guide 14, the first conveyance roller 1 and the second conveyance roller 1 are provided on the upstream side in the conveyance direction from right to left.
5,16, sensor 17 for registration timing registration,
A transfer roller 18, a second conveyance guide 19 and a fixing device 20 using a heating roller are arranged on the downstream side of the transfer roller 18, and a folding mirror 21 as a light introducing means and a process cartridge 11 are provided above the process cartridge 11. A laser scanner 22 as a light source means is arranged side by side. A guide 23, a discharge roller 24, and a discharge tray 25 of a discharge unit are arranged on the left side of the process cartridge 11, and a feeding cassette for storing the transfer material is provided below the first and second conveyance guides 14 and 19. 12 and a feeding roller 13 are provided.

When the photosensitive drum 10 uniformly charged by the charger 101 is exposed to the image light L through the laser scanner 22 and the folding mirror 21, an electrostatic latent image is formed on the photosensitive drum 10. It is formed. The electrostatic latent image is visualized as a toner image developed by the developing device 102 as the photosensitive drum 10 rotates, and is then transferred onto the transfer material P by the transfer roller 18. The photosensitive drum 10 after the transfer is cleaned by the cleaning device 103,
Prepared for the next image formation.

On the other hand, the transfer material P taken out from the feeding cassette 12 by the feeding roller 13 is the first conveying roller 1
After being moved to the upper second transport roller 16 along the first transport guide 14 via the second transport roller 5, the second transport roller 1
6. The timing is adjusted by the registration sensor 17, and the sheet is conveyed toward the photosensitive drum 10. Then, the transfer material P on which the toner image is transferred from the photosensitive drum 10 by the transfer roller 18 is sent to the fixing device 20 along the second transport guide 19, and the fixing device 20 heat-fixes the toner image. After receiving the sheet, it is loaded on the ejection tray 25 through the ejection guide 23 and the ejection roller 24.

Here, the method of supporting the equipment in the apparatus main body 1 and the external structure of the apparatus main body 1 will be described. Inside the apparatus main body 1, as shown in FIG. There is a structural frame 2 on which almost all units required for imaging are supported. The structural frame 2 is made of PC (polycarbonate), P or P in consideration of rigidity, dimensional stability, heat resistance and the like.
Approximately 30 to 50% of glass fiber, carbon fiber, etc. in resin such as PO (noryl), ABS (acrylonitrile butadiene styrene), HIPS (high impact styrene)
Three-dimensionally composed of mixed materials, high rigidity,
It is composed of high precision integrated injection molded products.
Therefore, each unit is accurately positioned and supported by the structural frame 2, and in particular, the main parts of the first transport guide 14 and the discharge guide 23, which determine the basic arrangement of the unit, are composed of the structural frame 2. Therefore, the positional accuracy of each unit is further improved.

That is, as shown in FIG. 3, the structural frame 2
A guide part 3 for guiding and holding the cassette 12 is provided above.
2, a motor holding portion 33 that holds the main motor M, a cartridge guide portion (guide groove) 30 that guides and holds the process cartridge 11, a holding portion 34 of the laser scanner 22, a holding portion 35 of the folding mirror 21, and a transfer roller 18. Holding section 36 of the carriage, holding sections 37a, 3 of the conveyance guide 19
7b, the holding portion 38 of the fixing device 20, the feeding roller 13, the conveying rollers 15 and 16, and the positioning and holding portion (not shown) of the discharge roller 24 are integrally molded, so that the above-mentioned units are mutually highly accurate. It is positioned and fixed to.

Further, since the guide portion 40 from the feeding portion to the transfer portion at the lower part of the unit is integrally formed with the structural frame 2, the positions of the transfer nip portion and the transfer material P generated by the pressure contact between the photosensitive drum and the transfer roller 18. The relationship is always high precision and stable. Therefore, it is possible to obtain a high-quality and beautiful image without image deviation or inclination during transfer.

Further, since the guide portion 23 of the transfer material P after fixing is also integrally formed with the structural frame 2, the fixing device 20
The positional relationship between the guide portion 23 and the guide portion 23 and the discharge roller 24 is also maintained with high accuracy. As a result, it is possible to prevent the transfer material P having a habit such as curl from being caught by the guide portion 23 and jammed due to the heat fixing, and it is possible to improve the reliability of the apparatus.

Further, the laser scanner 22, the folding mirror 21, and the photosensitive drum 10 are positioned on the structural frame 2.
Since the units are fixed, the alignment between the units can be easily performed, the irradiation position accuracy of the laser beam irradiated on the photosensitive drum 10 is improved, and the image position accuracy on the transfer material P is also improved.

Further, a pair of wall-shaped frames 2A, 2 having wall-shaped parallel surfaces constituting the side plates of the structural frame 2 are provided.
B is a connecting portion 3 integrally formed with each of the frames 2A and 2B.
9, 14, 34, 38, 40, 41 are integrally combined to form a strong three-dimensional structure, so that the rigidity is kept high and vibrations generated from the laser scanner 22 and the main motor M are easily attenuated, An effect that resonance is less likely to occur in the structural frame 2 is also obtained.

Furthermore, by inspecting the structural frame 2 as a single item, problems such as defective image formation and defective feeding can be found in advance. Therefore, appropriate measures should be taken at an early stage. It is also possible to obtain the effect of improving productivity.

As described above, by simplifying the apparatus to the utmost, increasing the degree of integration of the parts, downsizing, and concentrating almost all the functions required for image formation in the structural frame 2, it is possible to achieve a high degree of performance. You can make full use of injection molding technology.

By using a conductive metal filler (stainless steel, copper, etc.) as the substance mixed in the resin of the structural frame 2, the rigidity of the structural frame 2 can be further improved, and at the same time, 2-10Ω. It is possible to impart conductivity having an electric resistance value. As a result, the structural frame 2 can be used also as a conventional conductive substrate, and further, it is possible to obtain a shield effect for preventing electric noise generated from the control substrate in the device from leaking out of the device.

Further, by adding a highly elastic material such as butadiene rubber or butadiene rubber having a different polarity, or a urethane rubber material to the resin material of the structural frame 2, the vibration characteristic of the frame frame 2 is attenuated. Can be further increased, which leads to a reduction in pitch unevenness of the formed image. That is, by mixing the resin material of the structural frame 2 with another substance having various characteristics, various composite functions can be imparted to the structural frame 2.

The outer peripheral portion of the structural frame 2 is covered with an exterior cover 3 (see FIG. 1), a part of which is supported by a convex portion 2a (see FIG. 3) protruding from the structural frame 2. An opening / closing cover 4 that can be opened and closed centering around the support shaft 4a is attached to the upper right side of the upper side. By opening the opening / closing cover 4 in the counterclockwise direction in FIG. It is designed to be attached and detached. A pressure spring 26 for pressing and fixing the process cartridge 11 is attached to the open / close cover 4.

Next, a method of attaching / detaching the process cartridge 11 to / from the apparatus main body 1 will be described.

As shown in FIGS. 1 to 3, front and rear walls (wall-shaped frames) 2A and 2B of the structural frame 2 are provided with guide grooves 30 for drawing the curve for attaching and detaching the process cartridge 11, respectively. By engaging the drum shaft 10a of the photosensitive drum 10 protruding from the outer surface of the process cartridge 11 with the guide groove 30, the process cartridge 11 can be attached and detached. Guide groove 3
An upper end of 0 (hereinafter referred to as an insertion portion 30a) is positioned directly below the opening / closing cover 4, and a lower end of the other end (hereinafter referred to as a positioning portion 30b) is positioned between the folding mirror 21 and the transfer roller 18. The guide groove 3 so that the insertion portion 30a and the positioning portion 30b are connected by a downwardly convex arc.
It is formed of zero.

Further, a positioning groove 31 is formed in the positioning portion 30b of the guide groove 30 so as to extend downward (in this embodiment, about 3 mm), and the drum shaft 10a of the process cartridge 11 is located in the positioning groove 31. When the process cartridge 11 is dropped, the process cartridge 11
Will be positioned with respect to.

Here, the reason why the guide groove 30 for attaching and detaching the process cartridge 11 is formed in an arc shape will be described. That is, the folding mirror 21 supported by the support frame 2 via the holder 21a is disposed above the photosensitive drum 10 in the process cartridge 11, and below the photosensitive drum 10, the transfer roller 18 and the photosensitive drum are also provided. 1
A drive gear 27 etc. for rotating 0 etc. is arranged.
The drive gear 27 is used to drive the process cartridge 11 when driven.
It is arranged at a position slightly displaced from the photosensitive drum 10 so as not to push up. Further, first and second conveyance guides 14 and 19 for the transfer material P are arranged substantially horizontally on the left and right below the process cartridge 11, and the registration sensor 17 and the second conveyance are provided on the first conveyance guide 14. The roller 16 is arranged in a state of slightly projecting to the process cartridge 11 side.

Therefore, when the process cartridge 11 is attached to or detached from the apparatus main body 1, the process cartridge 11
And the folding mirror 21 and the transfer roller 1 on the apparatus body 1 side
8, it is necessary to avoid interference with the registration sensor 17, the second conveying roller 16, and the drive gear 27, and therefore the guide groove 30 needs to be formed in an arc shape. Also, by forming the guide groove 30 in an arc shape, the process cartridge 11 can be smoothly attached and detached.

Then, the opening / closing cover 4 is opened upward as shown in FIG. 2, and the drum shaft 10 of the process cartridge 11 is opened.
When the process cartridge 11 is pushed downward by engaging a with the insertion portion 30a of the guide groove 30 of the structural frame 2, the process cartridge 11
Is moved to the positioning portion 30b while drawing an arcuate locus along the guide groove 30 and avoiding interference with other units. Then, the drum shaft 10 a of the process cartridge 11 is finally dropped into the positioning groove 31 and positioned in the apparatus main body 1. In this case, the gear on the process cartridge 11 side and the drive gear 2 on the apparatus main body 1 side
7 and 7 are meshed with each other in accordance with the fall of the process cartridge 11 into the positioning groove 31, so that the meshing of these gears is smooth and smooth.

After the process cartridge 11 is positioned, if the opening / closing cover 4 is closed, the process cartridge 11 is pushed downward by the pressing spring 26 and fixed by the positioning groove 31. Further, when the process cartridge 11 is taken out from the apparatus main body 1, if the work is carried out in the reverse order of the above work, the process cartridge 11 can be taken out easily and smoothly without interfering with the peripheral shape and parts. ..

As described above, the process cartridge 11
Is attached to and detached from the apparatus main body 1 directly along the arc-shaped guide groove 30 provided in the structural frame 2. Therefore, the process cartridge 11 can be easily attached and detached, and the processed process cartridge 11 and other The positional relationship with the unit can be maintained with high accuracy.

In particular, since the distance between the drive gear 27 supported by the structural frame 2 on the apparatus main body 1 side and the gear on the process cartridge 11 side is maintained with high accuracy, the photosensitive drum 10
It is possible to obtain a clear image without unevenness in pitch or blurring, without causing unevenness in rotation. Further, since the laser scanner 22, the folding mirror 21, and the photosensitive drum 10 are positioned and fixed on the structural frame 2, it is easy to align the units, and the irradiation position accuracy of the image light L irradiated on the photosensitive drum 10 is also high. The image position accuracy with respect to the transfer material P is also improved. Therefore, a transfer defect such as a positional deviation with respect to the transfer material P does not occur.

Further, according to the cartridge mounting structure of the present invention, since it is not necessary to mount the process cartridge 11 or the like on the opening / closing cover 4, the structure of the opening / closing cover 4 is simplified and its weight is reduced. Therefore, the opening and closing work is facilitated, and the operational feeling is light and heavy, so that it is always constant and improved. That is, since the guide groove 30 of the structural frame 2 for attaching / detaching the process cartridge 11 is formed in an arc shape and the process cartridge 11 is attached / detached along the guide groove 30, the process cartridge 11 is attached / detached.
The process cartridge 11 does not interfere with other units, and the process cartridge 11 can be easily attached and detached. Further, since it is not necessary to attach and detach the process cartridge 11 to, for example, an opening / closing cover that opens and closes vertically, the opening / closing cover 4 and the like can be easily operated, and the structure of the opening / closing cover 4 and the like can be simplified.

FIG. 4 illustrates the structure of the process cartridge 11 described above.
As described above, the photosensitive drum 10, the charging device 101, the developing device 102, and the cleaning device 103 are integrally incorporated. 10 of the upper part of the developing device 102 in the figure
Reference numeral 2a denotes a toner accommodating portion, and the roller 102b facing the photosensitive drum 10 is a developing roller.

FIG. 5 is an external view of the process cartridge 11, showing two convex portions 10a and 10b which engage with the guide positioning groove 31. As shown in FIG. As mentioned above, 10a
Is the rotating shaft itself of the photosensitive drum 10, and the other convex portion 10b is the resin outer frame 104 of the process cartridge 11.
It is formed by integrally molding with a mouldle.

In addition, in the present invention, the process cartridge 11 is exemplified as one constituted by integrally assembling the charging device 101, the developing device 102 and the cleaning device 103, but a developing device as conventionally known is used. Other process cartridges having a different configuration, those in which only the developing device can be removed from the process cartridge with the process cartridge removed from the main body, and those in which toner can be replenished to the developing device are also applicable. ..

Further, in the groove mechanism for loading the cartridge, the structural frame 2 integrally molded as shown in FIG. 3 is not an essential requirement, but if the structural frame 2 shown in FIG. Since the size of the apparatus is increased, the size of the entire apparatus can be reduced by reducing the gap between the components, and the configuration can be said to be more effective because interference with other components can be minimized and the device can be attached and detached.

In the above embodiment, the laser scanner 22 is used as the information light irradiating means and the folding mirror 21 is used as the light introducing means. However, the invention is not limited to this, and an LED head array is used as an alternative means. Or
Needless to say, a SELFOC lens or a liquid crystal shutter may be used as the light introducing means. In the case of this LED head array, the LED array is arranged at the position of the laser scanner 22 and a condenser lens is arranged between the LED array and the folding mirror 21, or the LED array is arranged at the position of the folding mirror 21. It suffices to provide a combination of the lens and a condenser lens.

[0044]

As is apparent from the above description, according to the present invention, it is possible to position each unit with high accuracy and to increase the rigidity of the frame, thereby improving image quality and reliability. It is possible to improve.

Further, according to the present invention, the main body of the apparatus can be downsized, and the resource saving of the constituent members and the space saving of the installation area can be realized.

Further, according to the present invention, a process cartridge loading structure corresponding to the miniaturization of the apparatus main body can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a laser beam printer showing an embodiment of the present invention.

2 is an explanatory diagram showing a state in which a process cartridge is about to be loaded in the apparatus of FIG. 1. FIG.

FIG. 3 is a perspective view of a structural frame according to the present invention.

FIG. 4 is a cross-sectional view showing an example of a process cartridge.

5 is a perspective view of the process cartridge of FIG. 4. FIG.

FIG. 6 is a structural explanatory view of a laser beam printer device to which the structural frame of the present invention is not applied.

[Explanation of symbols]

 1 Image Forming Apparatus Main Body 2 Structural Frames 2A, 2B Wall Frame (Wall) 10 Photosensitive Drum (Electrophotographic Photoreceptor) 11 Process Cartridge 12 Feed Cassette 13 Feed Roller 14 First Transport Guide 15 First Transport Roller 16 2 Conveying Roller 18 Transfer Roller 19 Second Conveying Guide 20 Fixing Device 30 Guide Groove 31 Positioning Groove

Claims (2)

[Claims] 1. An image forming means for forming a developed image on an electrophotographic photosensitive member, a transfer material feeding means, and a transfer material conveying means.
A transfer unit, a fixing unit, a pair of wall portions having planar portions that are parallel to each other, and a connecting portion that connects the wall portions to each other, and these wall portions and the connecting portion are made of resin. A structural frame of an apparatus main body formed by an integral molding method, wherein the image forming means, the feeding means, the conveying means,
An image forming apparatus comprising a transfer unit and a fixing unit. 2. An electrophotographic photosensitive member, which is detachable from the main assembly of the apparatus, a process cartridge integrally having at least one process means acting on the photosensitive member for forming an image, and a transfer material. And a feeding frame, a transfer material transporting unit, a transfer unit, a fixing unit, and a structural frame of the apparatus main body including a wall portion having plane portions parallel to each other.
The loading of the process cartridge into the apparatus main body is performed by guiding the convex portion of the process cartridge into a groove portion that is provided in the structural frame and draws a curve toward a predetermined mounting position. An image forming apparatus characterized by.