Patent Grant
7228090
This application is based on Applications No. 2004-051346 and No. 2004-137187 filed in Japan, contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to an image forming apparatus such as a printer, a copier, and the like. More particularly, it relates to an image forming apparatus of which process unit including a photosensitive body or an intermediate transfer image belt, or the like is removable.
2. Description of Related Art
There have conventionally been devised image forming apparatuses of which wear-out portion such as photosensitive drum or the like is made in a removable unit so that an end user can replace it with a new one. For example, a tandem type image forming apparatus provided with four image forming sections for respective colors, namely, yellow, magenta, cyan, and black, has four image forming units for the respective colors. In case such an image forming unit is attached to a main body of an image forming apparatus, it is at least required that a photo sensitive drum be driven with rotation. Therefore, the photosensitive drum is connected to a driving power source installed in the main body so that force should be transmitted.
There have conventionally been suggested various structure of a connector section (see JP Laid-open Patent Publication No. 2000-214646and U.S. Pat. No. 6,397,029, for example) JP Laid-open Patent Publication No. 2000-214646 discloses an image forming apparatus which has a coupling axis separated from both a drive gear and a photosensitive drum. Each connector section of the apparatus has a twisted polygon column shaped hole and a twisted polygon column shaped projection. A hole and a projection are coupled and rotation is given to drive, whereby screwing force works on each other and positioning is aligned. Furthermore, U.S. Pat. No. 6,397,029 discloses coupling structure such that plural projections are arranged on an end portion of a universal joint built in a gear, and portions to be connected are coupled with the projections.
However, in the apparatus of above JP Laid-open Patent Publication, a hole and a projection attract each other to meet center of input/output axis like a screw when driving force is transmitted. As a result, stress is given to members for holding input/output axis and a cover box of an image forming apparatus, which causes a fear of distortion. To resolve this problem, accuracy is required to make shaft misalignment of the input/output axis small, or structure to provide tolerance for distortion at its holding section or the like. Structure tolerable to distortion makes an apparatus itself larger and causes cost-up, whereas higher accurate design makes it difficult to attach/remove an image forming unit. As to the coupling structure of above USP, since rotation driving force is applied to projections arranged on an end portion of a universal joint; the universal joint itself must be made of material of which strength is high.
The present invention has been made in order to solve the foregoing problem. It is an object of the present invention to provide an image forming apparatus capable of securing rotation transmission accuracy between input/output axes without giving stress to a holding portion despite shaft misalignment and without using material of high strength. Furthermore, it is also intended to provide an image forming apparatus capable of securing rotation transmission accuracy with simple structure, of which durability is high and dislocation of a joint is avoided.
According to a first aspect of the present invention, there is provided an image forming apparatus for forming an image attached with a removable process unit, the image forming apparatus comprising: a first driving force transmitting member for receiving rotary driving force to a process unit; and an intermediate driving force transmitting member for receiving rotary driving force from the first driving force transmitting member, the intermediate driving force transmitting member being arranged between the fist driving force transmitting member and a process unit, wherein either the first driving force transmitting member or the intermediate driving force transmitting member has a concave section and other driving force transmitting member has an end section located in the concave section, the end section has three edge sections at its side section, the concave section has contact sections to be in contact with the edge sections at side section, number of the contact sections is three or a multiple of three, the edge sections and the contact sections have different twisting angles, and rotary driving force is transmitted from the intermediate driving force transmitting member to a process unit. A photosensitive body unit and an intermediate transfer unit correspond to a process unit.
According to the first aspect of the present invention, rotary driving force is transmitted to the removable process unit via the first driving force transmitting member and the intermediate driving force transmitting member. Driving force transmission from the first driving force transmitting member to the intermediate driving force transmitting member is made by the contact sections of the concave section for the one of the transmitting members and three edge sections at the end section of the other transmitting member coming to contact with each other. Furthermore, since the edge sections and the contact sections have different twisting angles, there are three contact points, more specifically, one contact point for each of the three edge sections. In case of three-point contact, the center of the three contact points accords with that of the edge sections and the contact sections. Therefore, with contact state, rotation center of the first driving force transmitting member and that of the intermediate driving force transmitting member accord with each other. On the other hand, even if axis center of the first driving force transmitting member and that of the intermediate driving force transmitting member tilt, such tilt does not affect three-point contact and driving force transmission. Accordingly, since shaft misalignment of the first driving force transmitting member and the intermediate driving force transmitting member, which occurs when a process unit is attached, is absorbed by tilt of axis center, stress is never added to theirs holder sections. Thereby, even if centers of the input/output axes are not aligned with each other, stress is never added to theirs holder sections and rotation transmit accuracy between input/output axes can be secured without using material of high hardness.
As to different twisting angles, either the edge sections or the contact sections does not have twisted portion and the other one has twisted portion, for example. In such a case, the edge sections or the contact sections, whichever may have twisted portion. Alternatively, both of the sections may have twisted portions and their twisted angles or twisted direction may be different.
According to a second aspect of the present invention, there is provided an image forming apparatus comprising a main body and a process unit removable from the main body, forming an image attached a removable process unit to the main body, wherein the main body comprises a first driving force transmitting member for receiving rotary driving force to a process unit, the process unit comprises a second driving force transmitting member for receiving rotary driving force from the main body, either the main body or the process unit has an intermediate driving force transmitting member arranged between the first and the second driving force transmitting members, both a driving force transmitting portion between the first driving force transmitting member and the intermediate driving force transmitting member and a driving force transmitting portion between the intermediate driving force transmitting member and the second driving force transmitting member comprise a set of a concave section and an end section located in the concave section, the end section has three edge sections at its side section, the concave section has contact sections to be in contact with the edge sections at side section, number of the contact sections is three or a multiple of three, the edge sections and the contact sections have different twisting angles.
According to the second aspect of the present invention, rotary driving force is transmitted from the first driving force transmitting member to the second driving force transmitting member through the intermediate driving force transmitting member. Driving force transmission among those transmitting members is made by respective edge sections and the contact sections provided at both coupled sections coming to contact with each other at three points. Accordingly, shaft misalignment of the first driving force transmitting member and the intermediate driving force transmitting member or shaft misalignment of the intermediate driving force transmitting member and the second driving force transmitting member, which occurs when a process unit is attached, is absorbed by tilt of those shafts. Thereby, even if centers of the input/output axes are not aligned with each other, stress is never added to their holder sections and rotation transmit accuracy between input/output axes can be secured without using material of high hardness.
According to a third aspect of the present invention, there is provided an image forming apparatus for forming an image attached with a removable process unit, the image forming apparatus comprising: a first driving force transmitting member for receiving rotary driving force to the process unit, the first driving force transmitting member having a concave section of polygon shaped cross section at its process unit side; an intermediate driving force transmitting member of which one end portion is located in the concave section, the intermediate driving force transmitting member receiving rotary driving force from the first driving force transmitting member and transmitting rotary driving force to the process unit, and having a step section of polygon shaped cross section at its side surface; and a displacement stopper section arranged at the concave section and coming to contact with the step section when the intermediate driving force transmitting member escapes from the concave section.
According to the third aspect of the present invention, rotary driving force is transmitted to the process unit by the first driving force transmitting member for receiving rotary driving force to the process unit and the intermediate driving force transmitting member of which one end portion is located in the concave section. Since the intermediate driving force transmitting section has the concave section of polygon shaped cross section at its process unit side and one end of the intermediate driving force transmitting member of polygon shaped is located in its concave section, rotation transmit accuracy between input/output axes can be secured with such simple structure. Furthermore, since the step section of the intermediate driving force transmitting member is in contact with the displacement stopper section, displacement of the intermediate driving force transmitting member does not occur.
According to a fourth aspect of the present invention, there is provided an image forming apparatus comprising a main body and a process unit removable from the main body, forming an image attached a removable process unit to the main body, wherein the main body comprises a first driving force transmitting member for receiving rotary driving force to the process unit, the first driving force transmitting member having a concave section of polygon shaped cross section at its process unit side, the process unit comprises a second driving force transmitting member for receiving rotary driving force from the main body, the second driving force transmitting member having a concave section of polygon shaped cross section at its main body side, and either the main body or the process unit comprises: an intermediate driving force transmitting member of which both ends are located in the concave sections of the first and the second driving force transmitting members, the intermediate driving force transmitting member receiving rotary driving force from the first driving force transmitting member, transmitting rotary driving force to the second driving force transmitting member, and having a step section of polygon shaped cross section at its side wall, and a displacement stopper section arranged at the concave section and coming to contact with the step section when the intermediate driving force transmitting member escapes from the concave section.
According to the fourth aspect of the present invention, the second driving force transmitting member is arranged on the process unit and rotary driving force is transmitted from the first driving force transmitting member to the second driving force transmitting member through the intermediate driving force transmitting member. Both the first and second driving force transmitting members have the concave section of polygon shaped cross section, respectively, and both ends of the intermediate driving force transmitting member are located in those concave sections, rotation transmit accuracy between input/output axes can be secured with such simple structure.
According to a fifth aspect of the present invention, there is provided an image forming apparatus with a removable process unit comprising: a driving member arranged rotatably within the image forming apparatus, the driving member being connected to driving source and having a polygon shape; and a driven member arranged within the removable process unit, the driven member having a concave section in which the driving member is inserted, the concave section having polygon shaped inner surface, wherein rotary driving force is transmitted by contact of edge lines of the driving member and inner surface of the concave section of the driven section, and the edge lines of the driving member and the inner surface of the concave section of the driven member have different twisted angles.
According to a sixth aspect of the present invention, there is provided an image forming apparatus with a removable process unit comprising: a driving member arranged rotatably within the image forming apparatus, the driving member being connected to driving source and having a concave section of polygon shape at its end; and a driven member arranged within the removable process unit, being inserted in the concave section of the driving member, and having polygon shape, wherein rotary driving force is transmitted by contact of edge lines of the driven member and inner surface of the concave section of the driving section, and the edge lines of the driven member and the inner surface of the concave section of the driving member have different twisted angles.
The above and further objects and novel features of the invention will more fully appear from the following detailed description when the same is read n connection with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention.
For a better understanding of the present invention, reference is made to the following detailed description of the invention, just in conjunction with the accompanying drawings in which:
There will be described a first embodiment in detail by referring to drawings. In this embodiment, the present invention is applied to a tandem type color printer.
In a color printer 1 directed to this embodiment, as shown in
Each of the image forming sections 10Y, 10M, 10C, and 10K is structured similarly, constituted by a photosensitive drum 21, a developing section 22, exposure section 23, a charging section 24, a cleaner section 25, and an image transfer section 26. Since structure and operation of the respective composing elements are ordinary type, description will be omitted. As to each of the image forming sections 10Y, 10M, 10C, and 10K, at least on predetermined portion including a photosensitive body 21 is made of a unit, thereby to constitute an image forming unit 30. Image forming units 30 are removable from the cover body 20 of the color printer 1. As a generic name of them, all of the composing elements except image forming units 30 are termed as main body 2.
At the front side of the color printer 1 shown in
Next, there will be schematically described a connector portion of the main body 2 and an image forming unit 30 by referring to
An image forming unit 30 includes a photosensitive body 21 and is removable from the main body 2. As shown in the left side of
As shown in the right side of
The gear 43 transmits driving force generated by a power source arranged inside the main body 2 to the joint 45. Details will be described later, but concisely, the hole 47 for the joint holder section 43a and the joint 45 are in contact with each other partially to transmit rotation. The gear shaft holder 44 is fixed to the cover body 20 and holds the gear 43 rotatably. When an image forming unit 30 is attached to the main body 2, the spring 46 is pushed and shrunken, thereby to urge the joint 45 leftward in
Next, there will be described the shape of the joint 45. As shown in
As shown in
Next, there will be described transmission of rotation driving force by the joint 45 and the contact holes 36a. For better understanding of it,
It is to be noted that relation of diameters of the joint 45 and of the contact hole 36a is set to a range as follows. Looseness between the joint 45 and the contact hole 36a, difference of the diameters, is set smaller than looseness that the joint 45 idles in the contact hole 36a. That is, diameter of the joint 45 is set larger than minimum diameter of the contact hole 36a. Furthermore, the looseness is set larger than looseness the joint 45 can be just inserted in the contact hole 36a when centers of the joint 45 and of the contact hole 36a fall into maximum center and angle of deviation allowable for the image forming apparatus. That is, diameter of the joint 45 is set smaller than maximum diameter of the contact hole 36a. Since diameters of them are thus set, the joint 45 can be inserted in the contact hole 36a easily. Furthermore, for better insertion of the joint 45 into the contact hole 36a and meeting state of those, it is preferable that each edge line ‘p’ for the joint 45 is chamfered with a curved surface.
Since insertion of the joint 45 into the contact hole 63a is easy, insertion of an image forming unit 30 into the main body 2 in axis direction is easy, as well. At the stage immediately after the insertion, centers of the joint 45 and of the coupling 36 may not coincide completely. However, after that, the joint 45 and the contact hole 36a are relatively rotated, whereby they come to contact with each other at three points. At this stage, the centers coincide with each other due to the three contact points, viewed from its sectional position.
On the other hand, even if the centers somewhat deviate from each other, the joint 45 and the contact hole 36a can be in contact with each other at three points. Therefore, along rotation after insertion of those, deviation of center between the coupling 36 and the joint 45 is absorbed by tilt of the joint 45. Furthermore, the coupling 36 and the joint 45 are surely coupled each other due to the three contact points while deviation of center remains. Same mechanism works between one end of the joint 45 and the coupling 36 for an image forming unit 30, and between the other end of the joint 45 and the joint holder section 43a formed on the gear 43 for the main body 2.
Next, there will be described the fact that rotation is accurately transmitted even though two parts are coupling with centers of those axes deviating.
Vd1 (t)=r0*ω0 (1)
Furthermore, linear velocity of the gear 43 and that of the joint 45 are equal at their contact point. Therefore, provided that rotation radius of the joint 45 under coupled state, corresponding to the reference radius r0, is r1 (t), angular velocity of ω1 (t) for the joint 45 is expressed with an expression (2).
ω1(t)=Vd1 (t)/r1(t) (2)
Furthermore, when right hand side of the expression (1) is substituted for Vd1 (t) in the expression (2), an expression (3) is obtained.
ω1(t)=r0*ω0/r1(t) (3)
On the other hand, at the coupling 36 side, angular velocity of the joint 45 is ω1 and at their contact point, linear velocity of the joint 45 and that of the coupling 36 are equal. Accordingly, linear velocity Vd2 (t) of the coupling 36 at a point on rotation radius r1 (t) of the joint 45 is expressed with an expression (4).
Vd2(t)=r1(t)*ω1(t) (4)
When ω1 (t) in the right hand side of the expression (4) is substituted by the right hand side of the expression (3) an expression (5) is obtained.
On the other hand, since rotation radius of the coupling 36 at the contact point of the coupling 36 and the joint 45 is r0, angular velocity ω2 (t) of the coupling 36 is expressed with an expression (6)
Vd2(t)=r0*ω2(t) (6)
Accordingly, an expression (7) can be obtained by substituting the expressions (5) and (6).
ω2(t)=ω0 (7)
Thereby, angular velocity of the coupling 36 and that of the gear 43 are equal and the coupling 36 keeps steady state rotation. Accordingly, even if center of the joint 45 and that of the coupling 36 do not meet each other, they are coupled as they are and driving force in rotation direction is surely transmitted.
Furthermore, the coupling 36 may be formed as shown in
Thus structured, the junction of the joint 45 and the coupling 36 is just mated in rotation direction, and movement in an axis direction is free. Therefore, a user can remove this image forming unit 30 easily by moving it in an axis direction. When an image forming unit 30 is removed from the main body 2, it changes from a state as shown
As described, according to the color printer 1 directed to the present embodiment, joint 45 which has twisted triangle pole shape and contact holes 36a, 47 which are not twisted are used for the junction of the image forming unit 30 and the main body 2. Since they contact with one another at three points due to driving force in a rotation direction, their shaft centers in contact state coincide with one another. On the other hand, since there are three contact points, tilt of rotation axis is allowed to some extent. Accordingly, rotation is transmitted accurately with rotation velocity being kept constant while center of the axis tilts. Thereby, even if centers of the input/output axes are not aligned with each other, stress is never added to theirs holder sections and rotation transmit accuracy between input/output axes can be secured without using material of high hardness.
Furthermore, in the present embodiment, there is arranged a contact member of which end section has diameter smaller than maximum diameter of the concave section and larger than minimum diameter of the concave section. Thereby, insertion in the concave section of the edge section is easy. Furthermore, since contact members are arranged on the contact sections, the contact members receive contact force on contact points. Thereby, influence such as deformation of the concave section is avoided.
Furthermore, in the present embodiment, there is provided the elastic member for urging the first driving force transmitting member and the intermediate driving force transmitting member to be separated from each other, the concave section has a projecting section protruding inward from side section of the concave section, and the end section has displacement stopper section to be in contact with the projecting section from back side. Thus structure, the first driving force transmitting member and the second driving force transmitting member are separated when driving force is not transmitted. Therefore, attachment/removal of a process unit is easy. Furthermore, when those driving force transmitting members are separated, the projecting section and the displacement stopper section are made contact with each other, the intermediate driving force transmitting member does not get displaced.
Furthermore, in the present embodiment, both the first driving force transmitting member and the second driving force transmitting member have concave sections, the intermediate driving force transmitting member has the end sections to be located in the concave sections at its both ends, the concave section of the first driving force transmitting member has the projecting section protruding inward from side section of the concave section, and the intermediate driving force transmitting section has the displacement stopper section to be in contact with the projection section from back side and an elastic member for urging the first driving force transmitting member and the intermediate driving force transmitting member to be separated from each other. Thus structured, attachment/removal of a process unit is easy and the intermediate driving force transmitting member does not get displaced.
The inventive image forming apparatus can secure rotation transmission accuracy among input/output axes without giving stress to a holding portion despite shaft misalignment and without using material of high strength.
Hereinafter, the second embodiment of the present invention will be described in detail with reference to the accompanying drawings. This embodiment also concerns an application of the present invention to the tandem type color printer. The entire configuration of this embodiment is the same as
Next,
On the side of the main body 2, as shown on the right side of
The gear 43 transmits a driving force outputted from a drive unit provided inside the main body 2 to the joint 45. The gear shaft holder 44 is fixed to the cover box 20 so as to support the gear 43 rotatably. The joint 45 contains a main body section 45a which is of a twisted triangle pole. Further, a semispherical front edge section 45b is formed in the center of a forward side of
As shown in
When the image forming unit 30 is installed on the main body 2 as shown in
As shown in
Next, a transmission of rotary driving force with this twisted triangular prism joint 45 and the non-twisted triangular prism hole 36a will be described. Due to a relative rotation of the joint 45 and the coupling 36, each edge line ‘p’ of the joint 45 makes contact with the three contact faces 36b of the hole 36a only through a single point. As for the sectional position, the axes of the coupling 36 and the joint 45 overlap at the same position because of the three contact points. On the other hand, even if the inclinations of the both axes are slightly different, a deflection of the axis between the coupling 36 and the joint 45 is absorbed by the inclination of the joint 45. Further, even if the axes incline, the coupling 36 and the joint 45 are engaged with each other securely through the three contact points. This is the same for the relation between the joint 45 and a hole 47 formed by the protecting section 148a.
The joint 45 and the holes 36a, 47 are fit to each other through the three points for driving in the rotation direction so as to transmit a rotary driving force. This phenomenon occurs through both end portions of the joint 45 both on the side of the coupling 36 of the image forming unit 30 and the side of the joint holder section 43a formed in the gear 43 of the main body 2. Further, to improve an insertion and fitting condition between the joint 45 and the holes 36a, 47, preferably, each edge line ‘p’ of the joint 45 is rounded.
Because the rotary driving force is transmitted through the three contact points between the joint 45 and the holes 36a, 47 at this time, force is applied concentratedly on the three points of the holes 36a, 47. If wearing or plastic deformation occurs in the hole 36a, 47 due to a long term usage, unfavorably, the function for absorbing a deflection of the axis by the joint 45 may be hampered. In this color printer 1, the hole 47 of the gear 43 is constituted with an inside face of the protecting section 148a of the protection ring 148. Because the protection ring 148 has a large resistance to the plastic deformation, even if a concentrated force is applied, there is no fear that the plastic deformation may occur. Further, because the image forming unit 30 is replaced appropriately, the coupling 36 is never used continuously for too long a period. Thus, there is no fear that the hole 36a in the coupling 36 may be plastically deformed.
Further, as shown in
With the above described structure, the joint 45 and the coupling 36 are fit to each other only in the rotation direction while they can move freely in the axial direction. Therefore, user can fit or remove easily by moving this image forming unit 30 in the axial direction. If the image forming unit 30 is removed from the main body 2, the contact force by the coupling 36 in the direction to the right side of the same Figure to the joint 45 extinguishes from the state shown in
As described above, in the color printer according to this embodiment, the twisted triangular prism joint 45 and the non-twisted triangular prism holes 36a, 47 are employed in the connecting portion between the image forming unit 30 and the main body 2. Because these make contacts through three points due to a driving force in the rotation direction, this contact position makes the axial positions of the both coincide with each other. On the other hand, because the contact points are only three points, the inclination of the rotation axis is permitted to some extent. Thus, with the axis inclined, the rotation is transmitted at a high precision while maintaining the rotation velocity. Consequently, no stress is applied to the holding portion even if the axes of the input/output shafts deflect and even if no material having a high strength is used, the rotation transmission accuracy between the input and output shafts can be secured.
The protection ring 148, 49 are attached to the joint holder section 43a of the gear 43, so that its inner face functions as the hole 47. Therefore, even if the edge line ‘p’ of the joint 45 makes contact, there is no fear about wearing or plastic deformation. Thus, the durability of the color printer 1 is high.
Furthermore, in the present embodiment, there is a protection member inserted in the concave section and located between wall surface of the concave section and side surface of the intermediate driving force transmitting member, and the displacement stopper section is a part of the protection member. Therefore, the intermediate driving force transmitting member comes to contact with the protection member but not with the wall surface of the concave section. As a result, the wall surface of the concave section does not wear out and there is thus provided an image forming apparatus excellent in durability. Furthermore, since the displacement stopper section is provided on the protection member, the number of members for the apparatus does not increase.
Furthermore, in the present embodiment, there is a fixer section for fixing outer surface of the protection member and wall surface of the concave section to each other. Therefore, the outer surface of the protection member and the wall surface of the concave section are fixed together by the fixer section. Thereby, the protection member does not get displaced.
Furthermore, in the present embodiment, the protection member is superior to the first driving force transmitting member and the intermediate driving force transmitting member with respect to abrasion durability. Therefore, the first drive force transmit member or the intermediate drive force transmit member can be prevented from being worn out. Accordingly, there is thus provided an image forming apparatus excellent in durability.
In the meantime, this embodiment is only a mere representation and never restricts the present invention. Thus, the present invention may be improved or modified in various ways within a range not departing from the gist of the invention. Although the claws 148c, 49c for engaging the protection rings 148, 49 with the joint holder section 43a are provided on the outer face of the protecting sections 148a, 49a according to the above-described embodiment, they may be provided independently of the protecting sections 148a, 49a. Further, it is permissible to provide the protection rings 148, 49 with an engagement hole while providing the claw on the side of the joint holder section 43a. Further, the fixing method of the protection rings 148, 49 may be by press-fitting with a severe tolerance (for example, about −0.1˜0.0 mm) instead of the engagement between the fixing hole 43b and the claws 148c, 49c.
The image forming unit of the present invention is capable of securing a rotation transmission accuracy between the input and output shafts with a simple structure and has a high durability thereby preventing the joint from slipping out.
Hereinafter the third embodiment of the present invention will be described in detail with reference to the accompanying drawings. This embodiment is different from the first embodiment in only the connecting portion between the image forming unit 30 and the main body 2. Because the entire structure thereof is substantially equal, only different points will be described here.
In the main body 2, as shown on the left side of
Further, the joint 45 has a twisted triangular prism main body 45a as shown in
Further, as shown in
In the connecting portion of this embodiment, the inside diameter of the fixing section 44a of the gear shaft holder 44 and the outside diameter of the fixing section 33a of the shaft holder 33 of the image forming unit 30 are formed to be substantially equal to each other. Because the fixing section 33a and the fixing section 44a are disposed so as to oppose each other, as shown in
The color printer having the connecting portion of this embodiment as described in detail above, is capable of securing a rotation transmission accuracy between the input and output shafts even if no material having a large strength is used, without applying any stress to the holding portion when the input and output shafts deflect from each other, like the color printer 1 of the first embodiment.
Meanwhile, the present embodiment is a just mere exemplification, never restricting the present invention to any particular one. Therefore, naturally the present invention may be improved or modified in various ways within a range not departing from the gist. According to each of the respective embodiments, the joint 45 is substantially of triangular prism and the holes 47, 36a are provided in the joint holder section 43a and coupling 36 in which that joint is to be inserted. Instead, it is permissible to provide the joint holder section 43a and the coupling 36 with a substantially triangular prism convex portion and connect them through a joint having a hole on both end portions. Alternatively, it is permissible to provide the both end portions of the joint with a hole and a convex portion respectively.
Although according to each of the above-described embodiments, it is stated that the joint 45 is twisted while the holes 36a, 47 are not twisted, the same effect is obtained even if these are inverted.
Instead of the joint 45 according to each embodiment, as shown in
Instead of the joint 45 according to each embodiment, it is permissible to use a joint 56 provided with an L-shaped protrusion 56a instead of the front edge section 45b as shown in
According to the above-described embodiment, a removable process unit is the image forming unit 30 having the photosensitive body 21. However, the present invention is not restricted to this example, but this may be an intermediate image transfer belt unit. Further although according to the above-described embodiments, the present invention is applied to a color printer 1, the present invention is not restricted to these embodiments, but it may be applied to such an image forming unit as a monochrome printer, a copier and a facsimile.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-051346 | Feb 2004 | JP | national |
| 2004-137187 | May 2004 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 6035159 | Azuma et al. | Mar 2000 | A |
| 6324363 | Watanabe et al. | Nov 2001 | B1 |
| 6330409 | Watanabe et al. | Dec 2001 | B1 |
| 6397029 | Portig | May 2002 | B1 |
| Number | Date | Country |
|---|---|---|
| 62-156961 | Oct 1987 | JP |
| 07-332351 | Dec 1995 | JP |
| 10-153937 | Jun 1998 | JP |
| 10-153941 | Jun 1998 | JP |
| 2000-214646 | Aug 2000 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20050191092 A1 | Sep 2005 | US |
