Multi-directional driving mechanism and transfer device for an image forming machine using such mechanism

A multi-directional driving mechanism includes a moving plate supported rotatably on a supporting shaft and having an input portion and a plurality of output portions, a solenoid coupled to the input portion of the moving plate for causing the moving plate to pivot through a predetermined angle, and a plurality of coupling members each having one end coupled to the plurality of output portions provided on the moving plate. A transfer device for an image forming machine has contacting/separating mechanisms for moving a transfer belt unit, a moving mechanism for moving a cleaning blade, and the multi-directional driving mechanism, the other end each of the plurality of coupling members of the multi-directional driving mechanism being coupled to the contacting/separating mechanisms or the moving mechanism.

FIELD OF THE INVENTION 
This invention relates to a multi-directional driving mechanism capable of 
reciprocating driving in a plurality of directions using a single 
solenoid, and to a transfer device for an image forming machine using such 
driving mechanism. 
DESCRIPTION OF THE PRIOR ART 
As a transfer device to be mounted on an image forming machine, such as an 
electrophotographic apparatus or an electrostatic recording apparatus, 
Japanese Laid-Open Patent Publication No. Hei 4-345183, for instance, 
discloses a transfer system which has a transfer belt unit disposed 
opposite an image bearing member, the transfer belt unit comprising a 
driving roller, a driven roller disposed at a distance from the driving 
roller, a transfer belt looped around the driving roller and the driven 
roller, and a transfer roller disposed opposite the image bearing member 
with the transfer belt interposed therebetween. The transfer system 
applies a high voltage to the transfer roller to charge the transfer belt 
to a predetermined polarity, thereby sequentially attracting and 
transferring a toner image, formed on the surface of the image bearing 
member, to transfer papers fed between the image bearing member and the 
transfer belt. A transfer device with such a transfer system is equipped 
with a cleaning blade disposed in pressure contact with the surface of the 
transfer belt in order to remove toner adhered to the surface of the 
transfer belt. 
In the above-described transfer system, if the transfer belt is pressed 
against the image bearing member during a non-transfer operation, it is 
easily deformed or deteriorated at an early stage. To prevent this 
situation, or to deal readily with a jam of a transfer paper, if any, 
between the image bearing member and the transfer belt, the transfer belt 
unit is adapted to separate from the image bearing member during 
non-transfer intervals. Furthermore, if the cleaning blade is in contact, 
under pressure, with the transfer belt during non-transfer intervals, the 
transfer belt may be permanently deformed, adversely affecting transfer 
performance. Thus, the cleaning blade is desirably adapted to be moved to 
a non-operating position during non-transfer intervals. 
However, installing not only a driving mechanism for driving a 
contacting/separating mechanism which moves the transfer belt unit between 
a transfer position and a non-transfer position, but also a driving 
mechanism for driving a moving mechanism which moves the cleaning blade to 
the non-operating position during non-transfer intervals would pose the 
problems of requiring a complicated structure and a high cost. With a 
driving mechanism using an electric motor as a driving source, the use of 
a gear mechanism or a cam mechanism enables the driving mechanism to 
produce multi-directional outputs from the single driving source however, 
the use of a driving source operating in a reciprocating manner, such as a 
solenoid, presents difficulty in producing outputs in a plurality of 
directions by means of a relatively simple construction. 
SUMMARY OF THE INVENTION 
A first object of the present invention is to provide a multi-directional 
driving mechanism capable of producing outputs in a plurality of 
directions by means of a relatively simple structure using a solenoid as a 
driving source. 
A second object of the present invention is to provide a transfer device 
for an image forming machine adapted to actuate a contacting/separating 
mechanism for the transfer belt unit, and a moving mechanism for the 
cleaning blade, by means of the above multi-directional driving mechanism. 
To attain the first object, a first aspect of the present invention 
provides a multi-directional driving mechanism comprising a moving plate 
supported pivotably on a supporting shaft and having an input portion and 
a plurality of output portions; a solenoid coupled to the input portion of 
the moving plate for causing the moving plate to move at a predetermined 
angle; and a plurality of coupling members, each having one end coupled to 
the plurality of output portions provided on the moving plate. 
In the multi-directional driving mechanism according to the present 
invention, when the solenoid is energized, the moving plate, having the 
input portion coupled to the solenoid, is caused to move at a 
predetermined angle in a predetermined direction about the supporting 
shaft. The movement of the moving plate in the predetermined direction 
permits simultaneous outputs in a plurality of directions via the coupling 
members coupled to the plurality of output portions provided on the moving 
plate. 
To attain the second object, a second aspect of the present invention 
provides a transfer device for an image forming machine, which has a belt 
unit including a driving roller, a driven roller disposed at a distance 
from the driving roller, and a transfer belt looped around the driving 
roller and the driven roller and disposed opposite the image bearing 
member and a cleaning means disposed on the side opposite the image 
bearing member to clean the surface of the transfer belt wherein a 
multi-directional driving mechanism is further provided which comprises a 
contacting/separating mechanism for moving the belt unit between a 
transfer position and a non-transfer position, a moving mechanism for 
moving the cleaning means between an operating position and a 
non-operating position, a moving plate supported pivotably on a supporting 
shaft and having an input portion and a plurality of output portions, a 
solenoid coupled to the input portion of the moving plate for causing the 
moving plate to move at a predetermined angle, and a plurality of coupling 
members each having one end coupled to a plurality of output portions 
provided on the moving plate, the other end each of the plurality of 
coupling members of the multi-directional driving mechanism being coupled 
to the contacting/separating mechanism or the moving mechanism. 
In the transfer device of an image forming machine according to the present 
invention, when the solenoid constituting the multi-directional driving 
mechanism is energized during transfer, the moving plate having the input 
portion coupled to the solenoid is caused to pivot through a predetermined 
angle in a predetermined direction about the supporting shaft. The 
movement of the moving plate in the predetermined direction results in the 
actuation of the contacting/separating mechanism via the coupling member 
having one end coupled to one of the output portions of the moving plate, 
whereby the belt unit is brought to the transfer position. The movement of 
the moving plate in the predetermined direction, moreover, results in the 
actuation of the moving mechanism via the coupling member having one end 
coupled to another of the output portions of the moving plate, whereby the 
cleaning means is brought to the operating position. 
Other objects and features of the present invention will become apparent 
from the following description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Preferred embodiments of the transfer device for an image forming machine 
having a multi-directional driving mechanism constructed in accordance 
with the present invention will be described in detail below with 
reference to the accompanying drawings. 
FIG. 1 is an abridged structural view showing an embodiment of an image 
forming machine equipped with a transfer device constructed in accordance 
with the present invention. FIG. 2 is a front view of an image forming 
machine equipped with the transfer device of the present invention. 
An image forming machine 2 shown in FIG. 1 has an image bearing member 3, 
comprising a photosensitive drum, mounted rotatably therein. Around the 
image bearing member 3 are disposed sequentially as viewed in the 
direction of rotation indicated by arrow A a charging corona discharger 4, 
a developing device 5, a transfer device 6 constructed in accordance with 
the present invention, a cleaning unit 7, and a destaticizing lamp 8. The 
illustrated image forming machine 2 has an optical system disposed above 
the image bearing member 3 and composed of an illuminating lamp 9, a first 
mirror 10, a second mirror 11, a third mirror 12, a lens 13, and a fourth 
mirror 14. This optical system is adapted to cast light on a document, 
placed on a document bearing transparent panel (not shown), by way of the 
illuminating lamp 9, and to focus an image of reflected light on the image 
bearing member 3 via the first mirror 10, second mirror 11, third mirror 
12, lens 13, and fourth mirror 14. The image forming machine 2 has a 
transfer paper feeder 15 for feeding a transfer paper to the transfer 
device 6. The transfer paper feeder 15 has a transfer paper cassette 16 
for accommodating transfer papers, a transfer paper delivery roller 17, a 
paper feed roller pair 18, a guide passage 19, a carriage roller pair 20, 
a guide passage 21, and a resist roller pair 22. On the transfer paper 
feed-off side of the transfer device 6 are disposed a fixing roller pair 
23 and a discharge roller pair 24. In the thus constituted image forming 
machine, the respective members located below the one-dot chain line in 
FIG. 1 are disposed in a lower housing 25 of a machine body housing of a 
clamshell type, shown in FIG. 2, while the respective members located 
above the one-dot chain line in FIG. 1 are disposed in an upper housing 
26. The upper housing 26 has its right-hand lower end mounted by a shaft 
27 on the lower housing 25 so as to be free to pivot, as shown in FIG. 2. 
The transfer device 6 is disposed at a central portion of the lower 
housing 25, as shown by a two-dot chain line in FIG. 2. A front side plate 
of the lower housing 25 is provided with an opening 28 for mounting the 
transfer paper cassette 16. 
The image forming machine 2 constructed as above works in the following 
manner: While the image bearing member 3 is being rotationally driven in 
the direction of arrow A, the charging corona discharger 4 charges the 
photosensitive material on the image bearing member 3 to a specific 
polarity substantially uniformly. Then, the illuminating lamp 9 
illuminates a document placed on the document bearing transparent panel 
(not shown). An image of reflected light therefrom is projected onto the 
image bearing member 3 via the first mirror 10, second mirror 11, third 
mirror 12, lens 13 and fourth mirror 14, thereby forming a latent 
electrostatic image on the image bearing member 3. Then, the latent 
electrostatic image on the image bearing member 3 is developed to a toner 
image by the developing device 5. Separately, a transfer paper housed in 
the transfer paper cassette 16 of the transfer paper feeder 15 is 
delivered by the transfer paper delivery roller 17, and conveyed to the 
transfer device 6 past the paper feed roller pair 18, the guide passage 
19, the carriage roller pair 20, the guide passage 21, and the resist 
roller pair 22. The transfer paper conveyed to the transfer device 6 is 
passed between the image bearing member 3, having the toner image formed 
thereon, and a transfer belt (to be described later) of the transfer 
device 6, whereby the toner image is transferred onto the transfer paper. 
Then, the transfer paper has the toner image fixed by the fixing roller 
pair 23 and is discharged by the discharge roller pair 24. The image 
bearing member 3 having a transfer step completed in this manner is 
cleared of the toner, adhered onto the surface of the photosensitive 
material, by means of the cleaning unit 7. Further, the surface of the 
photosensitive material is irradiated with destaticizing light by the 
destaticizing lamp 8 for static elimination. 
Next, the transfer device 6 will be described with reference to FIGS. 3 to 
21. FIG. 3 is a perspective view of a transfer belt unit of the transfer 
device. FIG. 4 is a plan view of the transfer belt unit. FIG. 5 is a front 
view, partly broken away, of the transfer belt unit. FIG. 6 is a sectional 
view of the transfer belt unit. FIG. 7 is a sectional view taken on line 
X--X of FIG. 6. A transfer belt unit 29 illustrated in these Figures has a 
belt unit 30, and a unit housing 60 for housing and holding the belt unit 
30. 
The belt unit 30 will be described mainly with reference to FIGS. 8, 9 and 
10. The illustrated belt unit 30 has a supporting frame 31 as clearly 
shown in FIG. 8. The supporting frame 31 has a base portion 32 and end 
walls 33 and 34 formed, respectively, at the front end and the rear end of 
the base portion 32, and these are molded integrally from a plastic 
material. In the end walls 33 and 34 are formed, respectively, notched 
portions 331, 332, 333 and 341, 342, 343 which are all open upwards. To 
the end walls 33 and 34 are attached, by means of screws 37, 38 (FIG. 8 
shows only those on the end wall 34 side), supporting plates 35 and 36 
formed of a plastic material and supporting the respective rollers to be 
described later. At the central portions of the supporting plates 35 and 
36, cylindrical stoppers 351 and 361 projecting forward (upper-leftward in 
FIG. 8) and rearward (lower-rightward in FIG. 8) are integrally formed. 
These stoppers 351 and 361 function to contact the underside of a holder 
for rotatably supporting the image bearing member 3 and regulate the 
positional relationship between the belt unit 30 and the image bearing 
member 3. Also, a part of each of the supporting plates 35 and 36 
protrudes downwardly, and placing plates 355 and 365 are mounted to these 
protruding undersides (see FIG. 7). 
On the end walls 33 and 34 of the supporting frame 31 are mounted plastic 
supporting plates 39 and 40 for supporting a driving roller to be 
described later. The supporting plates 39 and 40 are joined to side end 
portions of the supporting plates 35 and 36 by pins 41 (FIG. 8 shows only 
that on the supporting plate 40 side) so as to be free to pivot, and by 
screws 42 (FIG. 8 shows only that on the supporting plate 40 side) so as 
to be set in place. On the outside surfaces of the supporting plates 39 
and 40 are provided, respectively, disk-shaped mounting portions 391 and 
401. The mounting portions 391 and 401 are provided, respectively, with 
two parallel surfaces 392, 392 and 402, 402 on their outer peripheries 
(see also FIG. 4). 
Between the supporting plates 39 and 40 is disposed a driving roller 43. 
The driving roller 43 is formed of a hollow material made of an aluminum 
alloy as illustrated in FIG. 9. To its front end (left end in FIG. 9) and 
rear end (right end in FIG. 9) are attached rotating shafts 431 and 432. 
The front rotating shaft 431 is journaled rotatably on a bearing 44 
disposed in the supporting plate 39. 0n the front rotating shaft 431 is 
mounted a gear 45, which is adapted to turn integrally with the rotating 
shaft 431 because an engagement groove 451 formed on the side surface of 
the gear 45 engages a pin 452 disposed so as to pass diametrically through 
the rotating shaft 431. To a front end portion of the rotating shaft 431 
is rotatably mounted a detachable member 46 having holes 461 and 462 for 
passage of mounting bolts. The detachable member 46 is provided with a 
position restricting means 465 which includes a guide portion 463 having a 
conical surface and a fitting portion 464 formed in continuation with the 
outer periphery of the guide portion 463. The functions of the thus 
constituted detachable member 46 will be described later. 
The rear rotating shaft 432 is journaled rotatably on a bearing 441 
disposed in the supporting plate 40. To the rear rotating shaft 432 is 
rotatably mounted a position restricting member 47, which is pressed 
rightward in FIG. 8 by a coiled spring 475 disposed between the position 
restricting member 47 and the mounting portion 401 of the supporting plate 
40. The position restricting member 47 includes a guide portion 471 having 
a conical surface, a fitting portion 472 formed in continuation with the 
outer periphery of the guide portion 471, and a flange portion 473. The 
functions of the thus constituted position restricting member 47 will be 
described later. On the rear rotating shaft 432 is mounted a driven gear 
48, which is adapted to turn integrally with the rotating shaft 432 
because an engagement groove 481 formed on the side surface of the gear 48 
engages a pin 482 disposed so as to pass diametrically through the 
rotating shaft 432. 
Between the supporting plates 35 and 36 are disposed a driven roller 49, a 
transfer roller 50, a tension roller 51, and an earth roller 52. The 
supporting structure on the supporting plate 35 side for these respective 
rollers, and that on the supporting plate 36 side for them are identical, 
and so only the supporting structure on the supporting plate 36 side is 
shown in FIG. 10. 
The driven roller 49 is formed from a cylindrical material made of an 
aluminum alloy, and its opposite end portions each terminate in a rotating 
shaft 491 of a reduced diameter. The rotating shaft 491 is rotatably 
journaled on a bearing 53 mounted on the supporting plate 36 (35). 
The transfer roller 50 comprises a rotating shaft 501 formed from a 
cylindrical material made from a steel product, and a spongy roller 
portion 502 mounted on the outer peripheral surface of the rotating shaft 
501 using a conductive adhesive (see also FIG. 6). The roller portion 502 
is made by impregnating a roll member, formed of a foam such as urethane 
foam or silicone foam, with a conductive substance such as carbon. The 
volume resistivity of the roller portion 502 is set at 10.sup.2 to 
10.sup.9 .OMEGA.cm. The impregnation of the roll member constituting the 
roller portion 502 with the conductive substance can be performed, for 
example, by dipping the roll member, formed of a foam such as urethane 
foam or silicone foam, in a solution of a powder of a conductive substance 
such as carbon to impregnate the roll member with the solution, and then 
drying it. The hardness of the roller portion 502 is set at a compression 
of 0.45 to 2.00 mm at a linear pressure of 3 g/cm. 
The reason why the roller portion 502 of the transfer roller 50 is composed 
of a relatively soft material such as a foam, e.g., urethane foam or 
silicone foam, having hardness expressed by a compression of 0.45 to 2.00 
mm at a linear pressure of 3 g/cm is as follows: Our tests showed that 
when the roller portion of the transfer roller was composed of a 
relatively hard material such as hard rubber, the pressure at the transfer 
point was high, and no problem occurred with an ordinary transfer paper. 
However, for an OHP film or the like, to which toner adheres with 
difficultly a partial missing phenomenon tended to occur in which the 
middle of the line of the image remains on the image bearing member 
without being transferred to the film. In the light of this finding, we 
tested various transfer rollers made of urethane foams. The volume 
resistivity of the roller portion of the transfer roller was set at 
10.sup.5 .OMEGA.cm, the volume resistivity of the transfer belt at 
10.sup.11 .OMEGA.cm, and the voltage applied to the transfer roller at 2.5 
kV. The tests showed that when the hardness of the roller portion was 
represented by a compression of less than 0.45 mm at a linear pressure of 
3 g/cm, the partial missing phenomenon occurred during transfer to an OHP 
film; whereas when the hardness of the roller portion was lower, no 
partial missing phenomenon occurred. However, when the hardness of the 
roller portion was low enough to involve a compression of greater than 
2.00 mm at a linear pressure of 3 g/cm, a predetermined frictional force 
was not obtained, making free-running with the transfer belt difficult. 
Also, a shearing force developing between the transfer belt and the roller 
portion damaged the surface of the roller portion. It was thus found that 
the hardness of the roller portion of the transfer roller should desirably 
be represented by a compression of 0.45 to 2.00 mm at a linear pressure of 
3 g/cm. 
The opposite end portions of the rotating shaft 501 constituting the 
transfer roller 50 are each journaled rotatably by a bearing 54 mounted on 
the supporting plate 36 (35). The bearing 54 is disposed at that position 
facing the cylindrical stopper 361 (351) where it is embedded on the 
stopper 361 (351) side from the internal surface of the supporting plate 
36 (35). Therefore, toner powder or dust only minimally penetrates the 
bearing 54 from inside the supporting plate 36 (35). The rotating shaft 
501 of the transfer roller 50 is adapted to be given a predetermined 
voltage by the voltage applying means 200 shown in FIG. 1. 
The tension roller 51 is disposed between the driven roller 49 and the 
transfer roller 50 and is formed from a cylindrical material made of an 
aluminum alloy. Its opposite end portions each terminate in a rotating 
shaft 511 of a reduced diameter. The rotating shaft 511 is rotatably 
journaled on a bearing 55 mounted on the supporting plate 36 (35). 
The earth roller 52 is disposed between the transfer roller 50 and the 
driving roller 43 and is formed from a cylindrical material made of an 
aluminum alloy. Its opposite end portions each terminate in a rotating 
shaft 521 of a reduced diameter. The rotating shaft 521 is rotatably 
journaled on a bearing 56 mounted on the supporting plate 36 (35). The 
earth roller 52 is grounded by a suitable grounding means. As seen from 
FIG. 6, the earth roller 52, the tension roller 51 and the transfer roller 
50 are in the following positional relationship: The transfer roller 50 is 
disposed such that the upper edge of its outer peripheral surface is 
situated below a straight line connecting together the upper edges of the 
outer peripheral surfaces of the earth roller 52 and the tension roller 51 
as viewed in the drawing. Thus, in a state in which a transfer belt 57 to 
be described later is wound around these rollers, the transfer roller 50 
separates from the transfer belt 57. 
An endless transfer belt 57 is wound around the driving roller 43, driven 
roller 49, transfer roller 50, tension roller 51 and earth roller 52 that 
are mounted on the supporting plates 39 and 40 and the supporting plates 
35 and 36 in the manner noted above. The transfer belt 57 is formed of a 
semiconductive material such as polychloroprene, and its volume 
resistivity is set at 10.sup.9 to 10.sup.12 .OMEGA.m. In mounting the 
transfer belt 57 over the respective rollers, the screws 42 that fix the 
supporting plates 39 and 40 to the end walls 33 and 34 of the supporting 
frame 31 are loosened to release the fixing of the supporting plates 39 
and 40 to the end walls 33 and 34 of the supporting frame 31, and the 
supporting plates 39 and 40 are pivoted about the pins 41. By so pivoting 
the supporting plates 39 and 40 about the pins 41, the transfer belt 57 
can be easily fitted over the respective rollers. Then, the supporting 
plates 39 and 40 are pivoted about the pins 41 to their original 
positions, and the screws 42 are tightened, whereby the transfer belt 57 
can be mounted with a predetermined tension. The width of the transfer 
belt 57 is set to be larger than the distance between the supporting 
plates 35 and 39 and the supporting plates 36 and 40. Both ends of the 
transfer belt 57 are situated at the central portions of the supporting 
plates 35 and 39 and the supporting plates 36 and 40. Hence, toner powder 
adhered to the transfer belt 57 only minimally penetrates a space defined 
by the supporting plates 35, 39, the supporting plates 36, 40, and the 
transfer belt 57. To prevent the transfer belt 57 from snaking during its 
operation, anti-snaking members 58, 58 are attached to the upper surfaces 
of the supporting plates 39 and 40. 
Next, a unit housing 60 for accommodating and supporting the belt unit 30 
will be described with main reference to FIGS. 6, 7 and 11. The unit 
housing 60 in the illustrated embodiment, as shown in FIG. 11, has a front 
side wall 63, a rear side wall 64, a bottom wall 65, a left side wall 66, 
and a right side wall 67, and is open upwards. These walls are integrally 
formed of a plastic material. In those upper parts of the front side wall 
63 and the rear side wall 64 which are adjacent the left side wall 66 
side, there are formed circular supporting holes 631 and 641 which 
pivotably support the mounting portions 391 and 401 provided on the 
supporting plates 39 and 40 journaling the driving roller 43 of the belt 
unit 30. The circular supporting holes 631 and 641 correspond in diameter 
with the mounting portions 391 and 401 and are open upwards. The width of 
each opening corresponds with the width of the mounting portions 391 and 
40 between the two parallel surfaces 392, 392 and 402, 402 formed in the 
mounting portions 391 and 401. Thus, the two mounting portions 391 and 401 
may be inserted into the circular supporting holes 631 and 641 from above 
in correspondence with the openings of the circular supporting holes 631 
and 641, and the belt unit 30 may be pivoted through approximately 
90.degree. about the mounting portions 391 and 401, whereby the belt unit 
30 can be mounted on the unit housing 60. 
Those end portions of the front side wall 63 and the rear side wall 64 
which are adjacent the right side wall 67 side are formed so as to project 
forward and rearward. In the upper parts of these end portions are formed 
notched portions 632 and 642 for receiving the stoppers 351 and 361 of the 
belt unit 30. At the projection of the front side wall 63 where the 
notched portion 632 is formed is provided a mounting portion 634 
protruding downwardly of the bottom wall 65. In the mounting portion 634 
are formed an elliptic positioning hole 635 and an elliptic hole 636 for 
passage of a mounting bolt, as shown in FIG. 5. At a central portion of 
the front side wall 63 shown in FIG. 5 is formed an engagement hole 633 at 
a position aligned with a slide rail to be described later. In the bottom 
wall 65 is provided a slide rail 654 at a position aligned with the 
engagement hole 633 formed in the front side wall 63, the slide rail 654 
extending from the front side end portion to the rear side end portion of 
the bottom wall 65. The slide rail 654 has guides 655, 656 projecting 
downwardly on either side thereof, and a slide surface 657 formed between 
the guides 655 and 656. The slide surface 657 is formed at nearly the same 
level as the upper end of the engagement hole 633 formed in the front side 
wall 63. 
In that part of the unit housing 60 which is beside the left side wall 66 
is formed a waste toner accommodating portion 68, extending in the 
back-and-forth direction along the left side wall 66, as shown in FIG. 6. 
In a lower part of the waste toner accommodating portion 68 is disposed a 
toner carriage member 69. The toner carriage member 69 has a rotating 
shaft 691 and a spiral blade 692 mounted on the rotating shaft 691. The 
toner carriage member 69 has an end portion of the rotating shaft 691 
journaled rotatably on the front side wall 63. The other end portion of 
the rotating shaft 691 is open to the waste toner accommodating portion 
68, and a part of the spiral blade 692 is supported rotatably by a guide 
cylinder 693 provided so as to project rearwardly from the rear side wall 
64 (see FIG. 11). As seen in FIG. 5, to an end of the rotating shaft 691 
is mounted a driven gear 70, which engages a pinion 711 of an intermediate 
gear 71 journaled rotatably on a shaft 713 provided in the front side wall 
63. The intermediate gear 71 has a wheel 712 integrally with the pinion 
711, and the wheel 712 is adapted to engage the gear 45 mounted on the 
rotating shaft 431 of the driving roller 43. The other end portion of the 
rotating shaft 691 projects beyond the front end of the guide cylinder 
693, and has at its front end a blocking disk 694 having nearly the same 
outside diameter as the outside diameter of the guide cylinder 693. Over 
the guide cylinder 693 is fitted a blocking cylinder 72 as shown in FIG. 
3. The blocking cylinder 72 has an engagement groove 721 formed axially 
from the internal end thereof. Since the engagement groove 721 engages a 
ridge 695 provided on the guide cylinder 693, the blocking cylinder 72 can 
move axially, but its turning is restricted. Also, the blocking cylinder 
72 has a flange 722 at its internal end and is pushed rearward by a coiled 
spring 723 disposed between the flange 722 and the rear side wall 64. 
The unit housing 60 has along the waste toner accommodating portion 68 a 
cleaning means 73 for cleaning the transfer belt 57 of the belt unit 30. 
The cleaning means 73 in the illustrated embodiment has a common holder 
74, a cleaning blade 75, and a paper dust removing member 76. The common 
holder 74 comprises a channel-like member having nearly the same length as 
the width of the transfer belt 57, and has a mounting portion 741 and a 
supporting portion 742. To a central part of the supporting portion 742 of 
the holder 74 is secured a mounting member 77. The mounting member 77 has 
at its base portion a hole 771 of a circular cross section drilled through 
the mounting member 77 in the longitudinal direction and partly having an 
opening portion 772. At a central portion of the mounting member 77 is 
integrally formed an operated lever 773. A supporting shaft 78 (see FIG. 
6) for pivotably supporting the mounting member 77 is provided at the 
bottom wall 65 of the unit housing 60. The supporting shaft 78 is formed 
integrally with supporting walls 79, 79 formed so as to extend from the 
bottom wall 65, and has two parallel surfaces with dimensions consistent 
with the diameter of the hole 771 and consistent with the width of the 
opening of the opening portion 772 at the outer periphery. To mount the 
mounting member 77 on the supporting shaft 78, the opening portion 772 is 
aligned with the two parallel surfaces formed on the supporting shaft 78, 
and the hole 771 is fitted over the supporting shaft 78 from above. Then, 
the mounting member 77 is pivoted through about 90.degree., whereby the 
operated lever 773 is mounted so as to be positioned substantially above 
supporting shaft 78, as shown in FIGS. 6 and 11. 
The cleaning blade 75 is formed of urethane rubber or the like, has nearly 
the same length as the width of the transfer belt 57, and is secured to 
the mounting portion 741 of the holder 74 by use of an adhesive or the 
like. The cleaning blade 75 has its edge in contact with the transfer belt 
during a transfer operation (see FIG. 21), thereby scraping off toner 
adhered to the transfer belt 57. The paper dust removing member 76 is 
composed of a foamed material such as a sponge, has nearly the same length 
as the width of the transfer belt 57, and is secured to the mounting 
portion 741 of the holder 74 by use of an adhesive or the like. The paper 
dust removing member 76 is disposed downstream of the cleaning blade 75 in 
the direction of operation of the transfer belt 57 and is formed so as to 
be thicker than the cleaning blade 75. The paper dust removing member 76 
is adapted to partially contact the transfer belt 57 during non-transfer 
intervals as well as during a transfer procedure. The paper dust removing 
member 76 removes paper dust adhered to the transfer belt 57, which is 
difficult for the cleaning blade 75 to remove, and has the function of 
smoothing toner accumulated at the position of contact when the cleaning 
blade 75 leaves the transfer belt 57. 
At an upper end of the left side wall 66 of the unit housing 60 is mounted 
a sealing plate 80 which covers the top of the waste toner accommodating 
portion 68. The sealing plate 80 extends from the front side wall 63 to 
the rear side wall 64, and has a sealing material 81, such as pile wool 
sponge or felt, on its surface facing the transfer belt 57 and at its 
portion facing the cleaning blade 75. As shown in FIG. 6, the edge portion 
of the cleaning blade 75 is brought into contact with the sealing material 
81 during non-transfer intervals. Hence the toner or paper dust adhered to 
the edge portion of the cleaning blade 75 can be removed during each 
non-transfer intervals. 
In the unit housing 60 is disposed a multi-directional driving mechanism 
100 for moving the cleaning means 73 between an operating position and a 
non-operating position, and also for moving the belt unit 30 between a 
transfer position and a non-transfer position. The multi-directional 
driving mechanism 100 is supported pivotably on a supporting shaft 101 
extending upward from the bottom wall 65 of the unit housing, and has a 
moving plate 110. The moving plate 110 is formed of a plastic material and 
has at its center a supporting tubular portion 111 rotatably fitted over 
the supporting shaft 101. In the illustrated embodiment, the moving plate 
110 has an input portion 112 and three output portions 113, 114, 115 
adjacent the outer peripheral portion thereof. An elongate hole 116 is 
provided at the input portion 112, and a pin 122 mounted on a plunger 121 
of a solenoid 120 is fitted into and connected to the elongate hole 116. 
Thus, when the solenoid 120 is energized and the plunger 121 is attracted, 
the moving plate 110 is moved through a predetermined angle in the 
direction of arrow E about the supporting shaft 101. When the solenoid 120 
is deenergized, the plunger 121 is returned by a built-in return spring 
whereupon the moving plate 110 is moved in the direction of arrow F about 
the supporting shaft 101 to its original state. 
The three output portions 113, 114, 115 provided on the moving plate 110 
reside at angles of nearly 90.degree. to each other. The output portion 
113 is connected to the operated lever 773, which constitutes the moving 
mechanism for the cleaning means 73, by means of a coiled spring 130 as a 
coupling member. In the illustrated embodiment, a ring is formed at an end 
of the coiled spring 130, and this ring and a coupling means 140, 
comprising, for example, a bolt inserted into a hole formed in the input 
portion 113 and a nut screwed on the bolt, enable that end of the coiled 
spring 130 to be coupled to the output portion 113 of the moving plate 
110. A ring is formed at the other end of the coiled spring 130 as well, 
and this ring and a coupling means 141, comprising, for example, a bolt 
inserted into a hole formed in the operated lever 773 and a nut screwed on 
the bolt, enable that other end of the coiled spring 130 to be coupled to 
the operated lever 773. The coupling portions at both ends of the coiled 
spring 130 have connections with some play. The coiled spring 130 is also 
disposed nearly tangentially to the direction of rotation of the output 
portion 113. In the illustrated embodiment, the coiled spring 130 is used 
as a coupling member for connecting the output portion 113 of the moving 
plate 110 to the operated lever 773. Because of this use, a tensile force 
is imparted to the coiled spring 130 when the cleaning blade 75 is brought 
to an operating position during transfer, and even when the transfer belt 
57 is stretched, the cleaning blade 75 is kept pressed against the 
transfer belt 57 owing to the tensile force of the coiled spring 130. 
The output portions 114 and 115 are coupled to contacting/separating 
mechanisms 150 and 150 for the belt unit 30 by means of coupling rods 160 
and 160 as coupling members. Each contacting/separating mechanism 150 
comprises a bored cylindrical supporting member 152, supporting side 
portions 153, 154 formed upright at the opposite end portions of the 
supporting member 152, a roller 156 supported on the supporting side 
portions 153 and 154 rotatably about a supporting shaft 155, and an 
operated lever portion 157 formed upright at a central portion of the 
supporting member 152 at an angle of nearly 90.degree. to the supporting 
side portions 153 and 154. These elements are molded from a plastic 
material. The contacting/separating mechanism 150 is rotatably supported 
by fitting into the hole of the supporting member 152 the supporting shaft 
165 which is attached to a bracket 170 mounted on the bottom wall 65 of 
the unit housing. The rollers 156 and 156 of the contacting/separating 
mechanisms 150 and 150 are disposed at a position aligning with the 
undersides of the placing plates 355 and 365 mounted on the undersides of 
the supporting plates 35 and 36 of the belt unit 30. A ring is formed at 
one end of each of the coupling rods 160 and 160, and these rings and 
coupling means 142 and 142, each comprising, for example, a bolt inserted 
into a hole formed in the output portions 114 and 115 and a nut screwed on 
the bolt, enable that end of the connecting rods 160 and 160 to be coupled 
to the output portions 114, 115 of the moving plate 110. A ring is also 
formed at the other end of each of the coupling rods 160 and 160, and 
these rings and coupling means 143, 143, each comprising, for example, a 
bolt inserted into a hole formed in the operated lever portions 157 and 
157 of the contacting/separating mechanisms 150 and 150 and a nut screwed 
on the bolt, enable that other end of the connecting rods 160 and 160 to 
be coupled to the operated lever portions 157 and 157. In the illustrated 
embodiment, the connecting rods 160 and 160 have bends 161 and 161 formed 
at the middle thereof. These bends 161 and 161 formed in the coupling rods 
160 and 160 are intended for accommodating manufacturing errors in the 
distances between the moving plate 110 and the operated lever portions 157 
and 157, mounted. The connected portions at both ends of the connecting 
rods 160 and 160 have connections with some play. The connecting rods 160 
and 160 are also disposed nearly tangentially to the direction of rotation 
of the output portion 113. 
Next, the slider mechanism for mounting the thus constituted transfer belt 
unit 29 on the lower housing 25 of the clamshell type will be described 
with reference to FIGS. 12 to 21. The lower housing 25 has a front side 
plate 85, a rear side plate 86 disposed at a distance from the front side 
plate 85, and a base plate 90 disposed between the front side plate 85 and 
the rear side plate 86. The front side plate 85, as shown in FIG. 13, is 
provided with a circular supporting hole 851 formed so as to be open 
upwards in correspondence with the fitting portion 464 of the detachable 
member 46 in the transfer belt unit 29. The front side plate 85 also is 
provided with a rectangular notched portion 852 in correspondence with the 
mounting portion 634 formed in the front side wall 63 of the unit housing 
60 and is provided with a hole 853 for engaging the engaging portion of a 
slider to be described later. In the rear side plate 86, as shown in FIG. 
14, are provided a hole 861 conforming to the fitting portion 472 of the 
position restricting member 47 in the transfer belt unit 29, and a hole 
862 which can be passed through by the blocking cylinder 72. 
On the base plate 90 of the lower housing 25 is disposed a slider 87 
extending between the front side plate 85 and the rear side plate 86. The 
slider 87 is composed of a steel material a a channel-like cross section, 
and its width is consistent with the width of the slide surface 657 formed 
between the guides 655 and 656 of the slide rail 654 (see FIG. 3). The 
upper surface of its top plate 871 forms a bearing surface 871a for 
bearing the slide surface 657 of the slide rail 654. As seen in FIG. 15, 
in the opposite side plates 872, 872 of the slider 87 are provided first 
elongate holes 873, 873 and second elongate holes 874, 874, each extending 
in the back-and-forth direction toward the rear end portion (upwards in 
FIG. 12, leftwards in FIG. 15, and rightwards in FIGS. 16 to 19). The 
first elongate holes 873, 873 provided on the rear end side are formed in 
a straight line parallel to the bearing surface 871a. The second elongate 
holes 874, 874, provided toward the front end side relative to the first 
elongate holes 873, 873, include a first parallel portion 874a parallel to 
the bearing surface 871a, an inclined portion 871b inclined upwards from 
the front end of the first parallel portion 874a, and a second parallel 
portion 874c extending parallel to the bearing surface 871a toward the 
front end side from the upper end of the inclined portion 874b. At the 
rear ends of the opposite side plates 872, 872 are provided stoppers 875, 
875 projecting upwardly of the bearing surface 871a. At the front ends of 
the opposite side plates 872, 872 are provided engagement portions 876 
which fit into the hole 853 formed in the front side plate 85 (see FIGS. 
13 and 16), and which have engagement depressions 876a for holding the 
slider 87 in an inclined state. At the front end of the top plate 871 is 
provided an engagement portion 877 which engages the engagement hole 633 
formed in the front side wall 63 of the unit housing 60. The engagement 
portion 877 and the engagement hole 633 formed in the front side wall 63 
constitute an engaging means in that they engage each other. The so 
constituted slider 87 has a first supporting pin 88 inserted into the 
first elongate holes 873, 873 formed in the opposite side plates 872, 872, 
and a second supporting pin 89 inserted into the second elongate holes 
874, 874. The two ends each of the first and second supporting pins 88 and 
89 are supported, respectively, by supporting brackets 901, 901 and 902, 
902 formed by cutting and erecting a part of the base plate 90. The first 
elongate holes 873, 873 and the second elongate holes 874, 874 formed in 
the opposite side plates 872, 872 of the slider 87, and the first 
supporting pin 88 and the second supporting pin 89 supported, 
respectively, by the supporting brackets 901, 901 and 902, 902 constitute 
a supporting means which supports the slider 87 so as to be movable in the 
back-and-forth direction and to be free to pivot in the up-and-down 
direction about the rear end portion. A coiled tension spring 92 extends 
between the second supporting pin 89 and an engagement portion 878 
provided in the top plate 871 of the slider 87 on the rear end side 
relative to the second supporting pin 89. Due to the tension of the coiled 
tension spring 92, the slider 87 is constantly urged toward the front end. 
Thus, the slider 87, as assembled, has its front end contacting the front 
side plate 85 (see FIG. 12). In this position, the first supporting pin 88 
is situated nearly at the center of the first elongate holes 873, 873 
formed in the opposite side plates 872, 872 of the slider 87, and the 
second supporting pin 89 is situated at the junction between the inclined 
portion 874b and the second parallel portion 874c of the second elongate 
holes 874, 874. When the front end portion of the slider 87 is lifted 
upward from this state, the slider 87 pivots about the first supporting 
pin 88, Simultaneously, the slider 87 is guided by the second elongate 
holes 874, 874 through which is inserted the second supporting pin 89, 
whereby the slider 87 moves toward the front end, and the engagement 
portions 876 reach the hole 853 formed in the front side plate 85. At this 
time, as shown in FIG. 16, the engagement portions 876 fit into the hole 
853, and the lower edge of the hole 853 engages the engagement depressions 
876a of the engagement portions 876. Thus, the slider 87 can be held in an 
inclined state in which its front end is situated upwards of the upper end 
of the front side plate 85. In this position, the rear ends of the first 
elongate holes 873, 873 are positioned at the first supporting pin 88, 
while the rear ends of the first parallel portions 874a of the second 
elongate holes 874, 874 are positioned at the second supporting pin 89. 
The slider mechanism for mounting the transfer belt unit 29 on the 
clamshell type lower housing 25 is constituted as described above. The 
procedure of mounting the transfer belt unit 29 will be explained. First, 
the front end portion of the slider 87 is lifted upwards, and the 
engagement depressions 876a of the engagement portions 876 are engaged 
with the lower edge of the hole 853 formed in the front side plate 85 to 
hold the slider 87 in an inclined condition as shown in FIG. 16. In this 
state, the slide surface 657 of the slide rail 654 formed in the unit 
housing 60 of the transfer belt unit 29 is placed on the bearing surface 
871a of the slider 87. As the transfer belt unit 29 is moved along the 
bearing surface 871a of the slider 87 as far as the position illustrated 
in FIG. 17, the rear end of the slide rail 654 contacts the stoppers 875, 
875 provided at the rear end of the slider 87. The engagement hole 633 
formed in the front side wall 63 of the unit housing 60 engages the 
engagement portion 877 provided in the slider 87, whereby the transfer 
belt unit 29 and the slider 87 are integrated. At this time, the driven 
gear 48 mounted on the driving roller 43 of the transfer belt unit 29 has 
passed through the hole 861 formed in the rear side plate 86, and the 
guide portion 471 of the position restricting member 47 contacts the upper 
edge portion of the hole 861. Also, the blocking cylinder 72 fitted over 
the guide cylinder 693 of the toner carriage member 69 has been inserted 
into the hole 862 formed in the rear side plate 86. When the transfer belt 
unit 29 and the slider 87 are pushed rearward from the state of FIG. 17, 
the engagement portion 876 and the hole 853 are disengaged. Thus, the 
transfer belt unit 29 and the slider 87 are pivoted downward about the 
first supporting pin 88 and guided along the second elongate holes 874, 
874 where the second supporting pin 89 has been inserted. When they come 
to a nearly horizontal condition as illustrated in FIG. 18, the bottom 
wall 65 aligning with the position of the mounting portion 634 of the 
front side wall 63 contacts a bottom edge 854 of the notched portion 852 
formed in the front side plate 85. At this time, the position restricting 
member 47 is positioned because its guide portion 471, having a conical 
surface, is guided, and its fitting portion 472 is fitted, into the hole 
861 formed in the rear side plate 86. At the same time, the flange portion 
473 contacts the rear side plate 86. The blocking cylinder 72, fitted over 
the guide cylinder 693 of the toner carriage member 69, is inserted into a 
hole 951 provided in a waste toner box 95 disposed behind the rear side 
plate 86, and the flange 722 contacts the rear side plate 86. A 
smaller-diameter portion between the detachable member 46 mounted at the 
front end portion of the driving roller 43 and the gear 45 is fitted into 
the circular supporting hole 851, formed in the front side plate 85, from 
its upper opening. When the transfer belt unit 29 and the slider 87 are 
further pushed rearward from the state of FIG. 18, the mounting portion 
634 contacts the front side plate 85 as shown in FIG. 19. At this time, 
the positioning hole 635 formed in the mounting portion 634 fits over a 
positioning pin 96 provided in the front side plate 85 as shown in FIG. 
13. The detachable member 46 is guided on the conical surface of the guide 
portion 463, constituting the position restricting means 465, and moved in 
the circular supporting hole 851. The fitting portion 464 is fitted into 
the circular supporting hole 851 for positional restriction. In this 
condition, as illustrated in FIG. 13, a mounting bolt 971 is inserted into 
the hole 636 for passage of a mounting bolt that is formed in the mounting 
portion 634, and, screwed into a threaded hole formed in the front side 
plate 85. Simultaneously, mounting bolts 972 and 973 are inserted into the 
holes 461 and 462 for passage of mounting bolts that are formed in the 
detachable member 46, and are screwed into threaded holes formed in the 
front side plate 85. Thereby, the transfer belt unit 29 can be mounted and 
fixed on the clamshell type lower housing 25. On the rear end side of the 
transfer belt unit 29, as shown in FIG. 19, the driven gear 48, mounted on 
the driving roller 43, is meshed with a transmission gear 99, mounted 
rotatably on a short shaft 98 attached to the rear side plate 86, and 
connected transmissibly to a driving unit (not shown). In the blocking 
cylinder 72 fitted over the guide cylinder 693 of the toner carriage 
member 69, the front end portion of the guide cylinder 693 protrudes from 
the blocking cylinder 72 into the waste toner box 95, since the flange 722 
pressed against the rear side plate 86 is immobile, but the guide cylinder 
693 moves. Thus, waste toner carried by the toner carriage member 69 can 
be discharged. To detach the transfer belt unit 29, mounted on the lower 
housing 25 this way, for replacement of parts and so forth, a procedure 
reverse to the above-described mounting procedure is performed, whereby 
detachment can be carried out easily. 
The positional relationship between the image bearing member 3 and the 
transfer belt unit 29 mounted on the lower housing 25 constituting the 
clamshell type machine body housing is shown in FIG. 20. The transfer 
roller 50 of the transfer belt unit 29 is positioned nearly directly below 
the image bearing member 3, and there is a gap between the transfer belt 
57 and the image bearing member 3. There is also a 1.00 to 2.00 mm gap 
between the transfer belt 57 and the transfer roller 50. The belt unit 30 
of the transfer belt unit 29, mounted on the lower housing 25 constituting 
the machine body housing, is pivoted upwards about the driving roller 43 
by the actuation of the contacting/separating mechanisms 150, 150 at the 
time of transfer, and is brought to a transfer position. Consequently, as 
shown in FIG. 21, the transfer belt 57 in is contact with the outer 
peripheral surface of the image bearing member 3 and is also pressed by 
the transfer roller 50. 
The transfer device of an image forming machine according to the 
illustrated embodiment is constituted as described above. Its actions will 
be explained hereinbelow. When the image forming machine is actuated from 
the non-operating state of the transfer belt unit 29 (FIG. 20), the 
solenoid 120, constituting the multi-directional driving mechanism 100 is, 
energized. When the solenoid 120 is energized and the plunger 121 
attracted, the moving plate 110 is moved through a predetermined angle in 
the direction of arrow E (FIG. 11) about the supporting shaft 101. Upon 
the movement of the moving plate 110 in the direction of arrow E, the 
coupling rods 160 and 160, having one end of each thereof coupled to the 
output portions 114 and 115 of the moving plate 110, are each pulled 
toward the moving plate 110. At the pull of the coupling rods 160 and 160 
toward the moving plate 110, the contacting/separating mechanisms 150 and 
150, having the operated lever portions 157 and 157 coupled to the other 
end of the coupling rods 160 and 160, are pivoted through a predetermined 
angle about the supporting shafts 165 and 165, thereby bringing the 
rollers 156 and 156 to their nearly uppermost positions. Thus, the 
supporting plates 35 and 36 of the belt unit 30, having mounted thereto 
the placing plates 355, 365 which rest on the rollers 156 and 156, are 
rotated upwards about the driving roller 43 and are pushed up (see also 
FIG. 7). As a result, as shown in FIG. 21, the transfer belt 57 is pressed 
against the image bearing member 3, and the transfer roller 50 is pressed 
against the transfer belt 57. By this contact under pressure, the roller 
portion of the transfer roller 50 is compressed by about 0.5 to 1.0 mm, 
and thus the transfer belt 57 can be contacted uniformly with the image 
bearing member 3 under a predetermined pressure. On the other hand, the 
coiled spring 130, having one end coupled to the moving plate 110, is 
pulled toward the moving plate 110. Thus, the mounting member 77, equipped 
with the operated lever 773 coupled to the other end of the coiled spring 
130, is pivoted clockwise in FIG. 20 about the supporting shaft 78. 
Consequently, the holder 74, having the mounting member 77 mounted 
thereon, is moved to the operating position shown in FIG. 21, so that the 
edge portion of the cleaning blade 75 mounted on the holder 74 is pressed 
against the transfer belt 57. Also, that edge portion of the paper dust 
removing member 76 mounted likewise on the holder 74 which is on the 
cleaning blade 75 side is brought into contact with the transfer belt 57. 
Next, when the driven gear 48 is rotationally driven via the transmission 
gear 99, transmissibly connected to the driving unit (not shown), the 
driving roller 43 having the driven gear 48 mounted thereon is caused to 
rotate. Upon its rotation, the transfer belt 57 is actuated in the 
direction of arrow B. Also, with the rotation of the driving roller 43, 
the driven gear 70 is rotated via the gear 45 mounted on the driving 
roller 43 and the intermediate gear 71. When the driven gear 70 is 
rotated, the toner carriage member 69, having the driven gear 70 mounted 
thereon, is rotated. Separately, the transfer roller 50 receives a 
predetermined voltage from the voltage applying means 200 (see FIG. 1). 
Via the transfer roller 50, a charge of a predetermined polarity is 
imposed on the transfer belt 57. Therefore, when a transfer paper is fed 
between the image bearing member 3 and the transfer belt 57, a toner image 
formed on the surface of the image bearing member 3 is sequentially 
attracted and transferred to the transfer paper by the action of the 
charge applied to the transfer belt 57 at the transfer portion where the 
image bearing member 3 and the transfer belt 57 face each other. The 
transfer paper having the toner image transferred thereto is conveyed by 
the transfer belt 57, has the toner image fixed by the fixing roller pair 
23, and is discharged from the discharge roller pair 24. The toner adhered 
to the surface of the transfer belt 57 is scraped off by the cleaning 
blade 75 during travel in the direction of arrow B, and is caused to fall 
into the waste toner accommodating portion 68. The toner dropped there is 
carried rearwards by the toner carriage member 69 and discharged into the 
waste toner box 95 from the front end of the guide cylinder 693. 
Then, at the time of a non-transfer operation, the driving roller 43 is 
stopped, and the voltage applied to the transfer roller 50 is shut off. 
When the solenoid 120 is deenergized, the plunger 121 is returned by means 
of a built-in return spring, the moving plate 110 is pivoted in the 
direction of arrow F (FIG. 11) about the supporting shaft 101, coming to 
the original state. Upon movement of the moving plate 110 in the direction 
of arrow F, the coupling rods 160 and 160 are pushed forwards and 
rearwards, respectively. Thus, the contacting/separating mechanisms 160 
and 160 are pivoted through a predetermined angle about the supporting 
shafts 165 and 165 in directions reverse to those during transfer. Hence, 
the belt unit 30 is pivoted downwards about the driving roller 43, 
whereupon the placing plates 355, 365 mounted on the supporting plates 35 
and 36 contact the stoppers 652 and 653 formed protrusively on the bottom 
wall 65 of the unit housing 60, and stop there. A state at the 
non-transfer position shown in FIG. 20 is produced. That is, the image 
bearing member 3 and the transfer belt 57, as well as the transfer belt 57 
and the transfer roller 50 are separated from each other. This can prevent 
the deformation of the transfer roller 50 arising from constant contact of 
the transfer roller 50 with the transfer belt 57. On the other hand, the 
coiled spring 130, having one end coupled to the moving plate 110, is also 
released, so that the mounting member 77 having the operated lever 773 
connected to the other end of the coiled spring 130 is pivoted 
counterclockwise in FIG. 20 about the supporting shaft 78. Consequently, 
the holder 74 having the mounting member 77 mounted thereon is moved to 
the position shown in FIG. 20, and thus the cleaning blade 75 mounted on 
the holder 74 separates from the transfer belt 57. This can prevent the 
deformation of the transfer belt 57 from arising due to the constant 
contact of the cleaning blade 75 with the transfer belt 57. In this 
condition as well, that edge portion of the paper dust removing member 76, 
mounted likewise on the holder 74, which is opposite to the cleaning blade 
75 side is in contact with the transfer belt 57. Since the paper dust 
removing member 76 is in constant contact with the transfer belt 57, the 
toner remaining adhered at the position of contact of the cleaning blade 
75 with the transfer belt 57 at the time of separation of the belt unit 30 
is smoothed by the paper dust removing member 76 even if the toner moves 
under the inertia of the transfer belt for a period until its stoppage. At 
a next transfer, therefore, toner build-up adhered to the transfer belt 
can be prevented from falling into the machine. 
The embodiments in which the multi-directional driving mechanism of the 
present invention is used most effectively in the transfer device of an 
image forming machine have been described above. However, the present 
invention is in no way restricted to these embodiments, and is applicable 
to various devices that produce outputs in a plurality of directions by 
means of a single solenoid. 
As described above, the multi-directional driving mechanism according to 
the first aspect of the present invention comprises a moving plate 
supported rotatably on a supporting shaft and having an input portion and 
a plurality of output portions; a solenoid coupled to the input portion of 
the moving plate for causing the moving plate to pivot through a 
predetermined angle; and a plurality of coupling members each having one 
end thereof coupled to the plurality of output portions provided on the 
moving plate. Thus, it can serve as an inexpensive, simple-structure, 
multi-directional driving mechanism which can produce outputs in a 
plurality of directions by means of a single solenoid. 
The transfer device of an image forming machine according to the second 
aspect of the present invention uses such a multi-directional driving 
mechanism to actuate a contacting/separating mechanism for moving the belt 
unit between a transfer position and a non-transfer position, and a moving 
mechanism for moving the cleaning means, which differ the 
contacting/separating mechanism in terms of the direction of movement, 
between an operating position and a non-operating position. Thus, the 
transfer device of an image forming machine can be simple in structure and 
low in price. 
According to the second aspect of the present invention, moreover, the 
coupling member for coupling the output portion of the moving plate in the 
multi-directional driving mechanism to the moving mechanism for moving the 
cleaning means is constituted of a coiled spring. Thus, a tensile force is 
imparted to the coiled spring when the cleaning blade is brought to an 
operating position during transfer. Even when the transfer belt is 
stretched, the cleaning blade is kept pressed against the transfer belt 
owing to the tensile force of the coiled spring. Thus, a cleaning function 
can be provided constantly. 
Furthermore, according to the second aspect of the present invention, the 
coupling members for coupling the output portions of the moving plate in 
the multi-directional driving mechanism to the contacting/separating 
mechanisms for moving the belt unit are composed of coupling rods having 
bends at the middle of each. These bends can accommodate manufacturing 
errors in the distances between the moving plate and the 
contacting/separating mechanisms when mounted. Thus, the 
contacting/separating mechanisms can be moved constantly smoothly.