Source: https://patents.google.com/patent/JPH08270642A/en
Timestamp: 2020-08-13 10:21:58
Document Index: 383723798

Matched Legal Cases: ['art 18', 'art 17', 'art 18', 'art 17', 'art 18', 'art 18', 'art 17', 'art, 10', 'art, 16']

JPH08270642A - Drive transmission mechanism, process cartridge, and electronic photograph image forming device - Google Patents
Drive transmission mechanism, process cartridge, and electronic photograph image forming device
JPH08270642A
JPH08270642A JP8062471A JP6247196A JPH08270642A JP H08270642 A JPH08270642 A JP H08270642A JP 8062471 A JP8062471 A JP 8062471A JP 6247196 A JP6247196 A JP 6247196A JP H08270642 A JPH08270642 A JP H08270642A
JP8062471A
利治 川合
1996-03-19 Application filed by Canon Inc, キヤノン株式会社 filed Critical Canon Inc
1996-03-19 Priority to JP8062471A priority Critical patent/JPH08270642A/en
1996-10-15 Publication of JPH08270642A publication Critical patent/JPH08270642A/en
238000000034 methods Methods 0.000 title claims description 76
230000005540 biological transmission Effects 0.000 title claims description 37
238000010168 coupling process Methods 0.000 claims abstract description 137
238000005859 coupling reactions Methods 0.000 claims abstract description 137
PURPOSE: To improve rotation precision by a method wherein a coupling projection shaft inserts a protrusion part having a positioning point and a coupling recessed shaft inserts a protrusion shaft, a recessed part with which the positioning point of the protrusion part makes contact is provided, and the shapes of the protrusion part and the recessed part are brought into a specified relation therebetween. CONSTITUTION: The protrusion part 18a of a coupling projection shaft 18 is formed in the shape of a regular triangular column and the recessed part 17a of the coupling recessed shaft 17 is engraved in the shape of a regular triangular column in which the protrusion 18a is insertable. Provided the diameter of a circumscribed circle R0 in the triangular shape of the protrusion part is D0 , the diameter of an inscribing circle R1 in the triangular shape of the recessed part is D1 , and the diameter of a circumscribed circle R2 is D2 , a formula of D1 <D0 <D2 is established. When the protrusion part 18a is inserted in the recessed part 17a through coupling engagement, there is a difference in the size of a triangle therebetween, the rough state of positioning precision of the recessed shaft 17 suffices for the protrusion shaft 18. The recessed shaft 17 is moved in a radial direction of rotation through rotation of the protrusion part 18 and finally, the three ridge lines of the triangular column of the protrusion part 18a is brought into contact with the inner surface of the recessed part 17a and the recessed shaft 17 is positioned. This constitution prevents the occurrence of a backlash and transmits a drive force with high rotation precession.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge and an electrophotographic image forming apparatus. Here, the electrophotographic image forming apparatus is an apparatus that forms an image on a recording medium using an electrophotographic image forming method. Examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copying machine, an electrophotographic printer (for example, laser beam printer, LED printer, etc.), a facsimile machine, a word processor and the like.
A process cartridge is a cartridge in which a charging means, a developing means or a cleaning means and an electrophotographic photosensitive member are integrally formed, and the cartridge can be attached to and detached from the main body of the image forming apparatus. And at least one of charging means, developing means, and cleaning means
The cartridge and the electrophotographic photosensitive member are integrally formed so that they can be attached to and detached from the main body of the image forming apparatus. Further, it means that at least the developing means and the electrophotographic photosensitive member are integrally made into a cartridge so as to be attachable to and detachable from the apparatus main body.
2. Description of the Related Art An electrophotographic image forming apparatus using an electrophotographic image forming system forms a latent image by selectively exposing an electrophotographic photosensitive member uniformly charged by a charging means according to image information. To do. Then, the latent image is developed by the developing means with toner to form a toner image. afterwards,
The toner image formed on the electrophotographic photosensitive member is transferred to a recording medium by a transfer unit to form an image.
Here, various methods have heretofore been considered for rotationally driving the electrophotographic photosensitive member. For example, as described in JP-A-58-139162, a pin fixed to the side surface of a gear provided on the main body is fitted into a recess provided on the side surface of the gear provided on the photosensitive drum. A method of rotating the photoconductor drum by combining them is known.
Further, as described in JP-A-63-4252, a method in which a helical gear provided on a main body is meshed with a helical gear provided on a photosensitive drum to rotate the photosensitive drum. There is also.
SUMMARY OF THE INVENTION The present invention is a further development of the above-mentioned conventional technique, and an object thereof is to provide a drive transmission mechanism, a process cartridge and an electrophotographic image forming apparatus capable of improving the rotation accuracy. To do.
Another object of the present invention is to provide a process cartridge and an electrophotographic image forming apparatus capable of improving image quality.
A typical structure according to the present invention for achieving the above object is a drive transmission mechanism for engaging a coupling convex shaft and a coupling concave shaft to transmit a rotational force, The coupling convex shaft has a convex portion having a shape having at least three positioning points, and the coupling concave shaft can insert the convex portion of the coupling convex shaft,
A concave portion having a shape with which the positioning point of the convex portion can come into contact,
When the circumscribed circle diameter of the convex shape is D 0 , the inscribed circle diameter of the concave shape is D 1 and the circumscribed circle diameter is D 2 , D 1 <D
It is characterized in that it is configured to have a relationship of 0 <D 2 .
Another structure is characterized in that the driving force is transmitted between the process cartridge and the image forming apparatus in which the process cartridge is mounted by the driving force transmission mechanism.
In the above structure, when the coupling convex shaft and the coupling concave shaft are engaged and driven, the positioning point of the convex portion comes into contact with the concave portion and the driving force is transmitted. At this time, if one of the coupling convex shaft or the coupling concave shaft is fixed in the radial direction of rotation and the other is movable in the radial direction of rotation, both members come into contact with each other at the positioning point when driven. The position of both members is determined and the drive is transmitted. As a result, uneven contact of the coupling and backlash of positioning are prevented.
Also, since the fitting of the convex portion and the concave portion is sufficient with a gap, it is possible to keep the requirement for the positioning accuracy of both members low.
BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the drawings.
First Embodiment First, a process cartridge according to the first embodiment and an image forming apparatus to which the process cartridge can be attached will be specifically described with reference to FIGS. 1 to 9. Here, as the order of description, first, the overall configuration of the process cartridge and the image forming apparatus using the process cartridge will be described with reference to FIGS. 2 to 5, and then FIGS.
The coupling configuration, which is a drive transmission mechanism of the process cartridge and the image forming apparatus main body, will be described with reference to FIG.
{Overall Configuration} FIG. 2 is a schematic explanatory view of the configuration of the image forming apparatus in which the process cartridge is detachably mounted, FIG. 3 is a schematic explanatory view of the configuration of the process cartridge, FIG. 4 is an external perspective view of the process cartridge, FIG. 5 is an explanatory diagram of the mounting configuration of the process cartridge.
As shown in FIG. 2, this electrophotographic image forming apparatus (laser beam printer) A irradiates a drum-shaped electrophotographic photosensitive member with a laser light image based on image information from an optical system 1 to expose it. A latent image is formed on the body, and the latent image is developed to form a toner image. Then, in synchronism with the formation of the toner image, the recording medium 2 is conveyed from the sheet feeding cassette 3a by a conveying means 3 including a pickup roller 3b, a feeding roller pair 3c, a conveying roller pair 3d, a registration roller pair 3e, and the like. The toner image formed on the photosensitive drum cartridged as the process cartridge B is transferred to the recording medium 2 by applying a voltage to the transfer roller 4 serving as a transfer unit, and the recording medium 2 is guided by the guide plate 3f. It is conveyed to the fixing means. The fixing means 5 is a fixing roller 5c including a driving roller 5a and a heater 5b.
The transfer toner image is fixed by applying heat and pressure to the recording medium 2 passing therethrough. Then, the recording medium 2 is conveyed by the pair of discharge rollers 3g and 3h, and is discharged to the discharge unit 6 through the reverse transport path. The image forming apparatus A can also be manually fed by the manual feed tray 3i and the rollers 3j.
On the other hand, the process cartridge B includes an electrophotographic photosensitive member and at least one process means. Here, as the process means, for example, a charging means for charging the electrophotographic photoreceptor, a developing means for developing the latent image formed on the electrophotographic photoreceptor, and a cleaning means for cleaning the toner remaining on the surface of the electrophotographic photoreceptor Etc. As shown in FIGS. 3 and 4, the process cartridge B of the present embodiment rotates a photosensitive drum 7 having a photosensitive layer which is an electrophotographic photosensitive member, and the surface thereof is applied with a voltage to a charging roller 8 which is a charging unit. It is configured such that it is uniformly charged by application, the information light from the optical system 1 is exposed to the photosensitive drum 7 through the exposure opening 9 to form a latent image, and the latent image is developed by the developing means 10. .
The developing means 10 sends out the toner in the toner storage portion 10a by the sending member 10b, rotates the developing roller 10d having the fixed magnet 10c built therein, and develops the developing blade.
A toner layer to which a triboelectric charge is applied by 10e is formed on the surface of the developing roller 10d, and the toner is transferred to the photoconductor drum 7 in accordance with the latent image to form a toner image to form a visible image. Is. And the transfer roller 4
After the toner image is transferred to the recording medium 2 by applying a voltage having a polarity opposite to that of the toner image to the recording medium 2, the cleaning blade 11a scrapes off the toner remaining on the photoconductor drum 7, and the squeeze sheet 11b scoops it to remove the waste toner. The cleaning means 11 collecting in the reservoir 11c is configured to remove the residual toner on the photosensitive drum 7.
Each member such as the photosensitive drum 7 constitutes a developing unit by welding a toner container 12a for containing toner and a developing frame 12b for holding a developing member such as a developing roller 10d. Are housed in a cartridge frame constituted by connecting a cleaning unit having the photosensitive drum 7 and the cleaning means 11 attached to the cleaning frame 12c to form a cartridge, and the cartridge is attached to and detached from the cartridge mounting means provided in the apparatus main body 13. It is installed as possible.
In the cartridge mounting means, when the opening / closing cover 14 is opened around the shaft 14a, as shown in FIG. 5, the cartridge mounting guide members 15 are mounted on the left and right side surfaces of the cartridge mounting space so as to face each other ( FIG. 5 shows only one side surface), and a guide portion that serves as a guide when the process cartridge B is inserted into the left and right guide members 15.
15a are provided facing each other. The process cartridge B is mounted on the image forming apparatus A by inserting bosses projectingly formed on both sides of the cartridge frame in the longitudinal direction into the guide portions 15a and closing the opening / closing cover 14.
When the process cartridge B is attached to the image forming apparatus A, as will be described later, the cartridge side coupling means and the main body side coupling means are combined,
The photosensitive drum 7 and the like can be rotated by being driven by the apparatus main body.
{Coupling Structure} Next, the structure of the coupling means, which is a drive transmission mechanism from the image forming apparatus main body to the process cartridge, will be described. 6 and 7
As shown in FIG. 3, cartridge side coupling means is provided at one end of the photosensitive drum 7. The flange 16 fixed to one end of the photosensitive drum 7 is provided with a coupling concave shaft 17, and a concave portion 17a is formed on the end surface of the concave shaft 17.
On the other hand, main body side coupling means is provided on the main body side of the image forming apparatus. The main body side coupling means has a coupling convex shaft 18 at a position that coincides with the rotation axis of the photosensitive drum when the process cartridge B is inserted.
Is provided. Rotational force is transmitted from the pinion gear 20 of the motor 19 via the transmission gear 21 to the coupling convex shaft 18 so that it can be driven and rotated, and the convex portion 18a is provided at the tip thereof.
As shown in FIG. 7, a transmission gear 21 is fixed to the coupling convex shaft 18, and the transmission gear 21 and the pinion gear 20 are helical gears. This helical gear has teeth with an inclination angle that causes the transmission gear 21 to generate thrust in the direction of arrow a in FIG. 7 when the coupling convex shaft 18 is rotated in the rotational direction during image formation. As a result, the coupling convex shaft 18 integral with the transmission gear 21 engages with the coupling concave shaft 17 provided on the photosensitive drum 7.
As shown in FIG. 8 (a), the opening / closing cover 14 is provided with an arc-shaped releasing member 22 centered on the shaft 14a, and the releasing member 22 has a tip portion as shown in FIG. ), A cam portion 22a having a gradually increasing thickness is formed. Therefore, as shown in FIG. 9, when the opening / closing cover 14 is opened to remove the process cartridge B, the cam portion 22a
Enters between the wall portion 23 and the transmission gear 21, and pushes out the side surface of the transmission gear 21 in the direction of arrow b. As a result, the coupling convex shaft 18 is retracted from the wall portion 23, the engagement with the coupling concave shaft 17 provided on the photosensitive drum 7 is released, and the process cartridge B is smoothly removed.
Next, the shapes of the concave portions 17a and the convex portions 18a which are the engaging portions of the coupling means will be described.
As shown in FIG. 6, the convex portion 18a is in the shape of a regular triangular prism, and the concave portion 17a is formed in the shape of a regular triangular prism in which the convex portion 18a can be inserted (similar shape). The ratio is greater than 0.5 and less than 1.0). Here, the relationship between the sectional triangle of the convex portion 18a and the sectional triangle of the concave portion 17a is
As shown in FIG. 1 (b), the diameter of the circumscribed circle R 0 of the convex triangle is D 0 , the diameter of the inscribed circle of the inscribed circle R 1 of the concave triangle is D 1 , and the circumscribed circle R 2 of the concave triangle is when the diameter was D 2, it is configured to have a relationship D 1 <D 0 <D 2 .
The coupling convex shaft 18 provided on the apparatus main body side is positioned so as to move in the direction of the rotation axis but not move in the direction of rotation radius as described above. On the other hand, the coupling concave shaft 17 provided on the process cartridge side is slightly movable in the rotation radius direction.
In the above coupling structure, when the process cartridge B is attached to the apparatus main body and the motor 19 is driven in the image forming direction, the coupling convex shaft 18 moves toward the coupling concave shaft 17 and the convex portion 18a and the concave portion are formed. When the phases of 17a are in phase (this embodiment is an equilateral triangle,
The two phases are engaged each other for each degree), and the two are engaged, and the rotational force is transmitted from the apparatus main body side to the process cartridge side. When this coupling is engaged, the convex portion 18a becomes the concave portion 17a.
When entering, as shown in Fig. 1 (a), there is a certain difference in the sizes of the two triangles, and they enter smoothly with a gap. Therefore, the positioning accuracy of the coupling convex shaft 18 and the coupling concave shaft 17 is sufficient to some extent in a rough state.
When the coupling convex shaft 18 rotates with the convex portion 18a in the concave portion 17a, as shown in FIG. 1 (b), the three ridge lines of the triangular prism of the convex portion 18a form the inner surface of the concave portion 17a. Although the driving force is transmitted to the coupling concave shaft 17 by contacting with, the three ridge lines come into contact with the concave portion 17a as described above when the coupling convex shaft 18 does not move in the radial direction of rotation. There is only one position. For this reason, the convex part
Both coupling shafts when 18a is in the recess 17a
Even if the positions of 17 and 18 are rough, the rotation of the coupling convex shaft 18 causes the coupling concave shaft 17 to move in the radial direction of rotation, and finally the three ridge lines come into contact with the inner surface of the concave portion 17a. At this point, the concave coupling shaft 17 is positioned.
By transmitting the driving force from the apparatus main body side to the process cartridge side by the coupling means having the above-mentioned configuration, it is possible to loosen the requirement for the positional accuracy of the coupling engagement. Therefore, the process cartridge can be easily assembled, and the cost can be reduced.
Further, it is possible to reduce uneven contact and backlash of the engaging portion due to the error of the coupling member, and to position the photosensitive drum 7 via the drive shaft on the apparatus main body side. The positional accuracy of the photosensitive drum 7 with respect to the optical system 1 provided on the side is increased, and the image quality can be improved.
[Second Embodiment] Next, a second embodiment of the drive transmission mechanism will be described.
An embodiment will be described with reference to FIG. The basic configurations of the process cartridge and the image forming apparatus are the same as those in the first embodiment described above, and thus redundant description will be omitted, and members having the same functions as those in the first embodiment will be denoted by the same reference numerals. .
The difference between the coupling structure shown in FIG. 10 and the first embodiment is that the convex portion 18a of the regular triangular prism of the coupling convex shaft 18 is twisted in the rotational direction. Correspondingly, the concave portion 17a of the coupling concave shaft 17 is also twisted in the rotational direction. The seating surface 17b is provided on the end surface of the coupling concave shaft 17.
By making the engaging portion twisted in the rotational direction as described above, when the coupling convex shaft 18 rotates in the image forming direction (direction of arrow c) in the engaged state, the coupling is generated. The concave-convex shafts 17 and 18 attract each other until they come into contact with the seat surface 17b. As a result, the connection between the two becomes more reliable.
Further, when the process cartridge B is removed from the apparatus main body, as shown in FIG. 11, when the motor 19 is driven in the direction opposite to that at the time of image formation (the direction of arrow d), the pinion gear 20 composed of a helical gear is used. And the thrust of the transmission gear 21 automatically releases the coupling. Therefore, it is not necessary to provide the release member 22 (see FIG. 8) as described in the first embodiment.
[Third Embodiment] Next, a third embodiment of the drive transmission mechanism will be described.
An embodiment will be described with reference to FIGS. 12 and 13. The basic structure of the process cartridge and the image forming apparatus is as follows.
Since it is the same as that of the first embodiment described above, redundant description is omitted, and the members having the same functions as those of the first embodiment are designated by the same reference numerals.
The difference between the coupling structure shown in FIG. 12 and the first embodiment is that the main body side coupling means is
The coupling concave shaft 17 made of OM, and the cartridge side coupling means to be engaged with the coupling concave shaft 17 are made of the POM coupling convex shaft 18. Further, as shown in FIG. Around the convex shaft 18, the photosensitive drum 7
The point is that a cylindrical wall portion 24 that is concentric with the center of rotation is provided integrally with the flange 16. Incidentally, FIG. 12 (b) is a view taken in the direction of arrows D and E in FIG. 12 (a).
Generally, when a concave portion and a convex portion having the same strength are coupled to each other to transmit a drive force, when the engaging portion is subjected to an excessive force, the concave portion is damaged rather than the convex portion. It's hard to do. Therefore, by providing the coupling concave shaft 17 which is not easily damaged on the apparatus main body side, damage to the main body side coupling means can be prevented even if an abnormal torque is generated. On the other hand, since the process cartridge itself is replaced when the toner is used up, the cartridge side coupling means is replaced with new one each time, so that the cartridge side coupling means does not have to have the same life as the main body side coupling means.
Further, by providing the wall portion 24 having the same height as the convex portion 18a around the convex shaft 18, the convex portion 18a
Does not project from the cartridge frame, and damage to the end of the convex portion 18a is prevented.
Further, the cylindrical wall portion 24 can be used as a guide when the process cartridge B is attached and detached along the guide portion 15a (see FIG. 5) of the image forming apparatus A.
As in the first embodiment, when the cartridge side coupling means is composed of the concave shaft 17 and the main body side coupling means is composed of the convex shaft 18, the allowable transmission torque of the concave shaft 17 is The same effect can be obtained by configuring the convex shaft 18 so as to be smaller than the allowable transmission torque.
For example, the coupling concave shaft on the cartridge side is made of POM, and the coupling convex shaft on the main body side is made of zinc die cast. According to this structure, even if an abnormal torque is generated, the convex shaft is prevented from being damaged because the allowable transmission torque of the coupling convex shaft on the main body side is large.
[Other Embodiments] Next, other examples of the process cartridge B and each part of the image forming apparatus according to the above-described embodiment will be described.
In the above-described embodiment, an example is shown in which the cross-sectional shapes of the convex portion 18a and the concave portion 17a constituting the engaging portion of the coupling means are equilateral triangles, but the ridgeline of the triangular prism may be rounded. By doing so, it is possible to more effectively prevent damage to the ridgeline of the convex portion 18a when the drive is transmitted by the coupling.
Further, the shapes of the convex portions 18a and the concave portions 17a may not be regular triangles in cross section as in the above-described embodiment, and if the polygonal column shape has three or more ridge lines (for example, a square column or the like), Since there are 3 or more positioning points when engaged,
Drive transmission and positioning can be reliably performed, and the strength of the coupling shaft can be increased.
Further, the shapes of the convex portion 18a and the concave portion 17a do not necessarily have to be similar shapes, as long as the ridge lines of the convex portion abut the inner surface of the concave portion at three or more places.
Further, if a taper is formed at the tip of the convex portion 18a, the entrance portion of the concave portion 17a, or both,
The convex portion 18a and the concave portion 17a can be joined smoothly.
Further, in the above-mentioned first embodiment, the cartridge side coupling means is constituted by the concave shaft 17, and the main body side coupling means is constituted by the convex shaft 18. The same effect can be obtained even if the main body side is replaced.
Further, in the above-described first embodiment, the opening / closing cover 14 is provided with the releasing member 22 for retracting the main body side coupling means to release the coupling, and the engagement is released in conjunction with the opening of the cover 14. As an example, the release member 22
Need not be limited to the open / close cover as long as it is a member that operates when the process cartridge is attached and detached. And
Even if the releasing member 22 is not necessarily provided, the coupling can be released by the thrust of the helical gear.
Although the above-mentioned process cartridge B is for forming a monochromatic image, the process cartridge is not limited to the case of forming a monochromatic image, but a plurality of developing means are provided and a multicolor image (for example, two colors) is provided. It can also be suitably applied to a cartridge that forms an image, a three-color image, a full-color image, or the like.
As the developing method, various known developing methods such as a two-component magnetic brush developing method, a cascade developing method, a touchdown developing method and a cloud developing method can be used.
The electrophotographic photosensitive member is not limited to the above-mentioned photosensitive drum, but includes, for example, the following. First, a photoconductor is used as the photoconductor, and examples of the photoconductor include amorphous silicon, amorphous selenium, zinc oxide, titanium oxide, and an organic photoconductor (OP).
C) etc. are included. The shape on which the photoconductor is mounted includes, for example, a drum-shaped, belt-shaped rotating body, a sheet-shaped body, and the like. Generally, a drum-shaped or belt-shaped one is used. For example, in the case of a drum type photoconductor, a photoconductor is vapor-deposited or coated on a cylinder of aluminum alloy or the like. Is.
As for the structure of the charging means, the so-called contact charging method is used in the first embodiment described above, but a metal shield such as aluminum is provided around the three sides of a tungsten wire which has been conventionally used as another structure. It goes without saying that a configuration may be used in which positive or negative ions generated by applying a high voltage to the tungsten wire are moved to the surface of the photosensitive drum to uniformly charge the surface of the drum.
The charging means may be of a blade type (charging blade), a pad type, a block type, a rod type, a wire type or the like, other than the roller type.
Further, as a method of cleaning the toner remaining on the photosensitive drum, the cleaning means may be constituted by using a blade, a fur brush, a magnetic brush or the like.
The above-mentioned process cartridge is
For example, an electrophotographic photosensitive member and at least one of process means
It is equipped with one. Therefore, as the mode of the process cartridge, in addition to the embodiment described above, for example, the electrophotographic photosensitive member and the charging unit are integrally made into a cartridge, which can be attached to and detached from the apparatus main body. The electrophotographic photosensitive member and the developing means are integrally formed into a cartridge,
It can be attached to and detached from the device body. The electrophotographic photosensitive member and the cleaning means are integrally made into a cartridge, which can be attached to and detached from the main body of the apparatus. Further, there is one in which an electrophotographic photosensitive member and two or more of the above-mentioned process means are combined into an integrated cartridge, which can be attached to and detached from the apparatus main body.
That is, the above-mentioned process cartridge is one in which the charging means, the developing means or the cleaning means and the electrophotographic photosensitive member are integrated into a cartridge, and the cartridge can be attached to and detached from the main body of the image forming apparatus. . Further, at least one of the charging means, the developing means, and the cleaning means and the electrophotographic photosensitive member are integrally made into a cartridge so that it can be attached to and detached from the main body of the image forming apparatus. Further, it means that at least the developing means and the electrophotographic photosensitive member are integrally made into a cartridge so as to be attachable to and detachable from the apparatus main body.
Further, in the above-mentioned embodiment, the laser beam printer is exemplified as the image forming apparatus, but the present invention is not limited to this, and other image forming apparatus such as an electrophotographic copying machine, a facsimile machine or a word processor can be used. It is also possible to use for.
The drive transmission mechanism for transmitting the driving force by engaging the coupling convex shaft and the coupling concave shaft is not limited to the drive transmission between the image forming apparatus main body and the process cartridge. It can also be used for drive transmission between members in the above equipment.
As described above, according to the present invention, when the coupling convex shaft and the coupling concave shaft are engaged and driven, the positioning point of the convex portion comes into contact with the concave portion, and there is no backlash, and there is no backlash. The driving force is transmitted with good rotation accuracy without being damaged. At this time, since the positions of the two are determined by the positioning points, the fitting of the convex portion and the concave portion is sufficient with a gap, and the requirement for the positioning accuracy of both members can be kept low.
Therefore, if the drive transmission mechanism according to the present invention is used to transmit the drive from the image forming apparatus main body to the process cartridge, coupling of the coupling and positioning of the electrophotographic photosensitive member and the like can be reliably performed. It is possible to obtain a quality image.
Further, in the drive transmission, the cartridge side coupling means is constituted by a convex shaft, or the allowable transmission torque of the main body side coupling means is set to be larger than the allowable transmission torque of the cartridge side coupling means. The damage of the coupling means can be prevented, and the life of the image forming apparatus can be extended.
FIG. 1 is an explanatory view of the shapes of a convex portion and a concave portion of a coupling means, (a) is a schematic explanatory view of a state where the convex portion is inserted into the concave portion
(b) is a schematic explanatory view of a state in which drive is transmitted.
FIG. 2 is a schematic diagram illustrating the configuration of an electrophotographic image forming apparatus.
FIG. 3 is a schematic diagram illustrating the configuration of a process cartridge.
FIG. 4 is an external perspective view illustrating the process cartridge.
FIG. 5 is an explanatory diagram of a mounting configuration of a process cartridge.
FIG. 6 is a schematic diagram illustrating the configurations of a cartridge side coupling means and a main body side coupling means.
FIG. 7 is a schematic explanatory view of the configurations of a cartridge side coupling means and a main body side coupling means.
FIG. 8 is a schematic explanatory view of the main body side coupling means when the opening / closing cover is closed.
FIG. 9 is a schematic explanatory view of a main body side coupling means when an opening / closing cover is opened.
FIG. 10 is a structural schematic explanatory view of a cartridge side coupling means and a main body side coupling means according to the second embodiment.
FIG. 11 is a schematic structural explanatory view when the coupling between the cartridge side coupling means and the main body side coupling means according to the second embodiment is released.
FIG. 12 is a schematic structural explanatory view of a cartridge side coupling means and a main body side coupling means according to the third embodiment.
FIG. 13 is a schematic perspective view showing the structure of the cartridge side coupling means according to the third embodiment.
DESCRIPTION OF SYMBOLS 1 ... Optical system, 2 ... Recording medium, 3 ... Conveying means, 4 ... Transfer roller, 5 ... Fixing means, 6 ... Ejecting section, 7 ... Photosensitive drum,
8 ... Charging roller, 9 ... Opening part, 10 ... Developing means, 11 ... Cleaning means, 12a, 12b, 12c ... Frame body, 13 ... Device body, 14 ... Open / close cover, 15 ... Guide member, 15a ... Guide part, 16 ... flange, 17 ... coupling concave shaft, 17a ... concave portion, 18 ... coupling convex shaft, 18a ... convex portion, 19 ... motor,
20 ... Pinion gear, 21 ... Transmission gear, 22 ... Release member, 23,
24 ... Wall
1. A drive transmission mechanism for transmitting a rotational force by engaging a coupling convex shaft and a coupling concave shaft, wherein the coupling convex shaft has a convex portion having a shape having at least three positioning points. The coupling concave shaft has a concave portion into which the convex portion of the coupling convex shaft can be inserted, and a positioning point of the convex portion can come into contact with the concave portion, and the circumscribed circle diameter of the convex portion is D 0. when the inscribed circle diameter of the recess shaped to D 1 and the circumscribed circle diameter and D 2, D 1 <D
A drive transmission mechanism characterized by having a relationship of 0 <D 2 .
2. The one of the convex coupling shaft and the concave coupling shaft does not move in the radial direction of rotation, and the other shaft is movable in the radial direction of rotation. The drive transmission mechanism described.
3. The shape of the convex portion and the concave portion is a shape in which the coupling convex shaft and the coupling concave shaft are twisted in a direction in which the coupling convex shaft and the coupling concave shaft attract each other when a rotational force is transmitted. The drive transmission mechanism according to claim 1 or 2, wherein a bearing surface is provided at an abutting portion of the shaft in the rotation axis direction.
4. The drive transmission mechanism according to claim 1, wherein the shape of the convex portion is a triangular prism or a shape in which the corners of the triangular prism are dropped.
5. A process cartridge attachable to and detachable from a main body of an image forming apparatus, an electrophotographic photosensitive member, process means acting on the electrophotographic photosensitive body, and a cartridge side for receiving driving force from the main body of the image forming apparatus. Coupling means, and the cartridge side coupling means is constituted by a coupling convex shaft or a coupling concave shaft of the drive transmission mechanism according to any one of claims 1 to 4. And process cartridge.
6. A process cartridge attachable to and detachable from the main body of an image forming apparatus, an electrophotographic photosensitive member, process means acting on the electrophotographic photosensitive body, and a cartridge side for receiving driving force from the main body of the image forming apparatus. The cartridge side coupling means is configured to allow the cartridge side coupling means when the driving force is transmitted by engaging with the main body side coupling means provided in the image forming apparatus main body. A process cartridge, wherein a transmission torque is set to be smaller than an allowable transmission torque of a main body side coupling means.
7. The process cartridge according to claim 6, wherein the cartridge side coupling means has a coupling convex shaft engageable with the coupling concave shaft of the main body side coupling means.
8. The process cartridge according to claim 7, wherein a wall portion is provided around the coupling convex shaft.
9. The method according to claim 8, wherein the wall portion has a cylindrical shape that is concentric with the rotation center of the electrophotographic photosensitive member, and serves as a guide when the process cartridge is attached to or detached from the main body of the image forming apparatus. Process cartridge.
10. The process cartridge comprises a charging means, a developing means or a cleaning means as the process means, and the electrophotographic photosensitive member integrally formed into a cartridge, and the cartridge can be attached to and detached from the main body of the image forming apparatus. The process cartridge according to claim 5 or 6, wherein
11. The process cartridge is a cartridge in which at least one of a charging unit, a developing unit, and a cleaning unit as the process unit, and the electrophotographic photosensitive member are integrally formed into a cartridge and attached to and detached from an image forming apparatus main body. The process cartridge according to claim 5 or claim 6, which enables the process cartridge.
12. The process cartridge is a cartridge in which at least a developing unit as the process unit and the electrophotographic photosensitive member are integrally made into a cartridge and can be attached to and detached from an image forming apparatus main body. The process cartridge according to claim 5 or claim 6.
13. An electrophotographic image forming apparatus, wherein a process cartridge is attachable / detachable and forms an image on a recording medium, a mounting means for mounting a process cartridge having an electrophotographic photosensitive member, and the mounted process cartridge. A main body side coupling means for transmitting a driving force, and a transport means for transporting a recording medium, wherein the main body side coupling means is any one of claims 1 to 4.
An electrophotographic image forming apparatus comprising the coupling convex shaft or the coupling concave shaft of the drive transmission mechanism according to any one of items 1 to 10.
14. The electrophotographic image forming apparatus according to claim 13, wherein the image forming apparatus is an electrophotographic copying machine, a laser beam printer, or a facsimile apparatus.
JP8062471A 1996-03-19 1996-03-19 Drive transmission mechanism, process cartridge, and electronic photograph image forming device Granted JPH08270642A (en)
JP8062471A JPH08270642A (en) 1996-03-19 1996-03-19 Drive transmission mechanism, process cartridge, and electronic photograph image forming device
JPH08270642A true JPH08270642A (en) 1996-10-15
ID=13201150
JP8062471A Granted JPH08270642A (en) 1996-03-19 1996-03-19 Drive transmission mechanism, process cartridge, and electronic photograph image forming device
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