JP2001083753A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable only one part of components to be easily and surely rotated without drastically increasing a cost by switching the state of the belt of a driving transmission mechanism to such a state that it is laid around all of plural rotary parts and such a state that it is laid around only one part of the plural rotary parts by moving the belt in a prescribed direction. SOLUTION: When a tensioner 60 is moved to a lower position H1 side (2a), a timing belt 51 is drawn into downward between rotary shafts 45M and 45C by a driven racing pulley 62 arranged at the upper part of the tensioner 60. Thus, the belt 51 is held so as to be laid around all of a rotary shaft 41 and the respective rotary shafts 45 of four developing devices. On the contrary, when the tensioner 60 is moved to an upper position H2 side (2b), the belt 51 is lifted upward between the shafts 45M and 45C by a driven racing pulley 63 arranged at the lower side of the tensioner 60. Thus, the belt 51 is held so as to be laid around only the shaft 41 and the rotary shaft 45K of the developing device for black.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, and a multifunction peripheral, and more particularly, to a plurality of rotary parts constituting a part of the apparatus by one rotary drive. It has a structural part that rotates simultaneously by the rotation power of the source, and, in addition to the time when all the components are simultaneously rotated, the time when only a part of it is to be rotated (in other words, only the part is stopped) Time).

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine or a printer using an electrophotographic system, parts constituting the apparatus include a photosensitive drum, a developing roll of a developing unit, a fixing roll of a fixing unit, and the like. A so-called rotating component that is driven to rotate at a predetermined rotation speed is used. Further, in an image forming apparatus provided with such rotating parts, some of the rotating parts are rotated by one electric motor or the like from the viewpoints of downsizing the apparatus, reducing cost, stabilizing the rotating operation, and the like. A configuration in which the driving source is driven to rotate is also used.

[0003]

By the way, in an image forming apparatus having a structure for rotating a plurality of rotating parts by the rotational power of a single rotation drive source, it is only necessary to rotate all the rotating parts at all times. There is no problem if it is completed, but if there is a time to rotate only a part of the rotating part and stop the remaining part, how to realize the selective rotation drive Is a problem.

For example, Japanese Patent Application Laid-Open No. Hei 10-232554 discloses a developer (toner) of yellow (Y), magenta (M), cyan (C) and black (k) around one photosensitive drum. Are provided, and after forming the toner images of the four colors on the photosensitive drums, the toner images are sequentially transferred to an intermediate transfer member and superimposed to form a color image. As an image forming apparatus, the rotational power on the photosensitive drum side is transmitted to four developing units via a gear mechanism to rotate the developing rolls and the like. By releasing the meshing of the gear mechanism while pushing up the rotating shafts of the developing rolls in the three developing devices that contain the color developers and retracting them from the developing position, black Only the developing unit to the operative state, the image forming apparatus is shown to the other developing devices inoperative state.

However, in this image forming apparatus, the developing device itself must be moved, and the fixing of the developing device to the apparatus main body becomes insufficient. The generated vibration may be transmitted to the entire developing device and also to the photosensitive drum. As a result, there is a problem that the image quality of the obtained image is adversely affected.

To solve such a problem, an electromagnetic clutch is provided between a drive shaft to which rotational power is transmitted from the photosensitive drum side and a rotary shaft in each of the developing units. A countermeasure for switching the transmission of rotational power by operating or not operating the electromagnetic clutch is considered. However, in this case, as many electromagnetic clutches as the number of the developing devices are required, and since the electromagnetic clutch is for driving transmission, generally a clutch having a large rated torque must be used, which is a great deal. This leads to an increase in cost.

On the other hand, in order to improve the fixability of the fixing device, for example, when the power is turned on or when an image is formed from a small-sized document to a large-sized document, the fixing roll of the fixing device is idly rotated before starting the image forming operation. There is an image forming apparatus that performs an operation of sufficiently warming the temperature of the roll surface (particularly, the pressure roll surface).

In such an apparatus, when the fixing device and the photosensitive drum are configured to be rotated by the rotational power of the same rotary drive source, when the fixing roll of the fixing device idles, the photosensitive drum also rotates. As a result, there is a problem that the drum surface is worn by a cleaning blade or the like pressed against the photosensitive drum, and the life of the photosensitive drum itself is shortened.

Incidentally, in order to solve such a problem, as described in JP-A-8-334912, the surface of the photosensitive drum is formed using a charge transporting polycarbonate or polyester resin having excellent abrasion resistance. As described in Japanese Patent Application Laid-Open No. 9-281770, a method of displacing an image forming unit that does not need to be rotated to make it inoperative may be considered. However, the former countermeasure does not provide a sufficient effect, and the latter countermeasure requires a large-scale mechanism for displacing the image forming unit, resulting in an increase in cost. There is a problem that it must be secured.

The present invention has been made in order to solve each technical problem in the prior art as described above.
Its purpose is to have a structure for rotating a plurality of rotating parts by one rotation drive source, and when there is a time to rotate only some of the plurality of rotating parts, the components themselves are displaced. An object of the present invention is to provide an image forming apparatus capable of simply and surely rotating only a part of components without causing any cost increase.

[0011]

An image forming apparatus according to the present invention (first invention) that achieves the above object has a plurality of rotating parts constituting a part of the apparatus and a rotating power for rotating the plurality of rotating parts. , And a belt is wound between the drive shaft of the rotary drive source and each of the rotary shafts of the plurality of rotary components to simultaneously apply the rotational power of the rotary drive source to the plurality of rotary components. A drive transmission mechanism capable of transmitting, and a state in which the belt of the drive transmission mechanism is moved in a predetermined direction and wrapped around all of the plurality of rotating parts, and a state where the belt is wrapped around only a part of the plurality of rotating parts. And a belt moving mechanism for switching to hold.

According to the image forming apparatus of the first aspect, when rotating only a part of the rotating component, the belt of the drive transmission mechanism is wrapped around only the rotating component to be rotated by the belt moving mechanism. To be moved. As a result, only the rotating parts on which the belt is wrapped rotate by transmitting the rotational power from the belt, and the rotating parts on which the belt is not wrapped do not rotate because the rotational power is not transmitted from the belt.

Further, the image forming apparatus of the present invention (second invention) which achieves the above object, has a plurality of rotating parts constituting a part of the apparatus, and outputs rotational power for rotating the plurality of rotating parts. And a mechanism capable of simultaneously transmitting the rotational power of the rotary drive source to the plurality of rotary components by wrapping a belt between the rotary drive sources and the drive shaft of the rotary drive source and the rotary shafts of the plurality of rotary components. A narrow first fixed pulley and a first idle pulley, which are mounted side by side on a drive shaft of the rotary drive source and a rotary shaft of a stop type rotary component having a time to stop rotation among the rotary components. And a second fixed pulley having a wide width substantially corresponding to the total width of the first fixed pulley and the first idle pulley, which is attached to the rotating shaft of the continuous rotating component that continues rotation, which is the remaining rotating component. Do A dynamic transmission mechanism, a state in which the belt of the drive transmission mechanism is displaced in the axial direction and wrapped around the first fixed pulley and the second fixed pulley, and a state wrapped around the first idling pulley and the second fixed pulley, respectively. And a belt displacement mechanism for switching to hold.

According to the image forming apparatus of the second aspect, when only a part of the rotating part is rotated, the belt of the drive transmission mechanism is fixed to the continuous rotating part to be rotated by the belt displacement mechanism. It is displaced so as to be wrapped around the pulley side, while it is displaced so as to be wrapped around the idling pulley side for a stop type rotary component having a time to stop. As a result, only the continuous rotary part whose belt is wrapped around the fixed pulley rotates by transmitting rotational power from the belt, and the stationary rotary part whose belt is wrapped around the idle pulley rotates with the belt. No rotation because there is no power transmission.

Further, the image forming apparatus of the present invention (third invention) which achieves the above object has a plurality of rotating parts constituting a part of the apparatus, and outputs rotational power for rotating the plurality of rotating parts. Rotating drive sources, a wide first gear attached to a first drive transmission shaft that transmits rotational power to a rotating shaft of a continuous rotating component that continues to rotate among the rotating components, and the remaining rotating components A second gear having a small width attached to a second drive transmission shaft for transmitting rotational power to a rotation shaft of a stop type rotary component having a time to stop rotation, the first gear and the second gear, and the rotation A gear train composed of a plurality of gears arranged to be interposed between a third gear attached to the drive shaft of the drive source and transmitting the rotational power of the rotary drive source to the first gear and the second gear; Drive transmission mechanism used Of the gear train of the drive transmission mechanism, a final gear that finally meshes with the first gear and the second gear is axially displaceable, and the final gear is axially displaced to displace the first gear and the first gear. A gear displacing mechanism is provided to switch between a state in which the second gear meshes with the first gear and a state in which only the first gear meshes.

According to the image forming apparatus of the third aspect, when only a part of the rotating component is rotated, the final gear of the gear train in the drive transmission mechanism is rotated by the gear displacement mechanism for the continuous rotating component. A narrow second drive transmission shaft mounted on the second drive transmission shaft for the stationary rotary part, while being engaged only with the wide first gear mounted on the first drive transmission shaft; Are in a state of non-meshing. As a result, only the continuous rotating component on the first drive transmission shaft side that meshes with the final gear is connected to the drive transmission mechanism and the first drive transmission shaft.
Rotational power is transmitted from the drive transmission shaft to rotate, and the stationary rotary component on the second drive transmission shaft side that does not mesh with the final gear does not rotate because there is no transmission of rotational power.

Further, according to the present invention (the fourth aspect) which achieves the above object,
The image forming apparatus according to the present invention includes a plurality of rotating parts constituting a part of the apparatus, one rotating drive source for outputting a rotating power for rotating the plurality of rotating parts, and a rotating power of the rotating drive source. A mechanism capable of transmitting to a plurality of rotating parts,
Between the rotary drive source and the stop type rotary component having a time to be stopped among the plurality of rotary components, when the rotary drive source rotates forward, the rotation power is maintained in a state where it is transmitted. And a switching drive transmission mechanism interposed with a switching mechanism for maintaining a state in which rotational power is not transmitted when the drive source rotates in the reverse direction.

According to the image forming apparatus of the fourth aspect, when only a part of the rotating component is rotated, the rotary drive source rotates in the reverse direction, and the stationary rotary component is rotated by the switching mechanism of the switching drive transmission mechanism. The rotation power is not transmitted.
On the other hand, the other rotating components not having such a switching mechanism are in a state where the rotating power is transmitted. As a result, the stationary rotary component with the switching mechanism interposed does not rotate, but the rotary component without the switching mechanism rotates.

Further, in the image forming apparatus according to the fourth aspect of the present invention, the switching mechanism of the switching type drive transmission mechanism includes a drive transmission shaft for transmitting the rotational power of the rotary drive source and a rotary shaft of the stationary rotary component. In the meantime, when the rotary drive source rotates forward, the power is locked and the rotational power is transmitted. On the other hand, when the rotary drive source is rotated reversely, the lock is released and the protrusion is unlocked. It is desirable that the connection be made by coupling. In this case, the continuous rotating component for continuing the rotation may be configured to be connected to a drive transmission structure capable of transmitting rotational power even in the case of reverse rotation of the rotary drive source without using the coupling.

In such a configuration, when only a part of the rotating component is rotated, the rotation drive source rotates in the reverse direction, and the switching mechanism connects the drive transmission shaft and the rotation shaft of the stationary rotary component. Is in a non-locked state. This allows
The stationary rotating component does not rotate because no rotational power is transmitted, but the rotating component without the coupling rotates.

Further, in the image forming apparatus according to the fourth aspect of the present invention, the switching mechanism of the switching drive transmission mechanism may be configured such that the stop-type rotary component meshes with a gear attached to a drive transmission shaft to which rotational power of the rotary drive source is transmitted. The gear attached to the rotating shaft is connected to the rotating shaft via a one-way clutch that is in a transmission state when the rotation driving source rotates forward, and is in a non-transmission state when the rotation driving source rotates reversely. It is desirable. In this case, the continuous rotating component that continues rotating may be configured to be connected to a drive transmission structure that can transmit rotational power even when the rotational drive source is rotating in the reverse direction without using the one-way clutch.

With this configuration, when only a part of the rotary component is rotated, the rotation drive source rotates in the reverse direction, and a switching mechanism that connects between the drive transmission shaft and the rotary shaft of the stationary rotary component. Is in a non-transmission state. As a result, the stationary rotary component does not rotate because no rotational power is transmitted, but the rotary component without the one-way clutch rotates.

Further, in the image forming apparatus according to the fourth aspect of the present invention, the switchable drive transmission mechanism includes a gear attached to a drive transmission shaft to which the rotational power of the rotary drive source is transmitted, and a rotation that is not the stationary rotary component. A first gear train that transmits the rotational power at a normal speed during normal rotation of the rotary drive source and a gear attached to the rotary shaft of the continuous rotary component that continuously rotates the rotary drive source. It is desirable to have a configuration in which a second gear train for transmitting the rotation power at a speed lower than the normal speed is provided.

With this configuration, when only the continuous rotary component is rotated, the rotational power is transmitted at a speed lower than the normal speed by the second gear train. As a result, the continuous rotating component rotates at a lower speed than normal.

Further, the image forming apparatus of the present invention (fifth invention) which achieves the above object, has a plurality of rotating parts constituting a part of the apparatus, and outputs a rotating power for rotating the plurality of rotating parts. A rotary drive source and a mechanism capable of transmitting the rotational power of the rotary drive source to the plurality of rotary components, wherein the rotary drive source and a stop type rotary component having a time to stop among the rotary components During rotation of the rotary drive source at a normal speed, the clutch is connected by centrifugal force and the rotary power is transmitted, while at a low speed lower than the normal speed of the rotary drive source. And a drive transmission mechanism interposed with a centrifugal clutch in which the clutch is disengaged during rotation and no rotational power is transmitted. In this case, the continuous rotary component for continuing rotation may be configured to be connected to a drive transmission structure capable of transmitting rotational power even at low speed rotation of the rotary drive source without using the centrifugal clutch. .

According to the image forming apparatus of the fourth aspect, when only a part of the rotating component is rotated, the rotary drive source rotates at a low speed, and the stationary rotary component is rotated by the centrifugal clutch of the drive transmission mechanism. The clutch is disengaged. On the other hand, the other rotating parts without the centrifugal clutch are in a state where their rotational power is transmitted. As a result, the stationary rotary component with the centrifugal clutch interposed does not rotate, but the rotary component without the centrifugal clutch rotates.

The rotating parts in the first to fifth aspects of the present invention are not particularly limited as long as they are parts constituting the image forming apparatus. For example, the rotating parts of the developing unit, the photosensitive drum, and the fixing unit of the fixing unit are used. Roll, photosensitive belt drive roll,
These include an intermediate transfer drum, a driving roll for an intermediate transfer belt, a sheet conveying drum, and a driving roll for a sheet conveying belt.
The plurality of rotating parts when rotated by one rotation driving source may be any combination of the same kind, combination of different kinds, or a combination of both.

[0028]

[First Embodiment] FIG. 1 is a schematic configuration diagram showing a printer as an image forming apparatus according to an embodiment to which the present invention (first invention) is applied.

The printer according to the first embodiment has a schematic structure.
Yellow (Y), magenta (M), cyan (C), and yellow (Y) individually formed by four image forming units 10Y, 10M, 10C, and 10K based on image data input from the outside.
The four color black (k) toner images are transferred to the intermediate transfer belt 2.
This is a color printer capable of forming a so-called full-color image by performing primary transfer so as to be superimposed on the surface of No. 0 and then performing secondary transfer from the intermediate transfer belt 20 to the recording sheet P side. The printer can also form a monochrome image by operating only the black image forming unit 10K among the four image forming units.

Each of the image forming units 10 forms a toner image by an electrophotographic process, and basically includes a photosensitive drum 11, a charger (charging roll) 12, a latent image forming device 13, and a developing device 14. , Transfer unit (transfer roll) 1
5 and a drum cleaner 16 are similarly provided. According to each of the image forming units 10, the photosensitive drum 11 rotating at a constant speed in the arrow direction C is uniformly charged by the charger 12, and then the charged surface is charged from the latent image forming device 13 to the charged surface. An electrostatic latent image is written by scanning and exposing a laser beam (dotted arrow) corresponding to the color-separated image signal, and then the latent image is developed by the developing device 14.
The toner image is developed by the developer supplied from the developing roller (not shown), and finally, the toner image is electrostatically applied to the surface of the intermediate transfer belt 20 passing between the photosensitive drum 11 and the transfer device 15. The primary transfer is performed sequentially. The surface of the photosensitive drum 11 after the transfer is cleaned by a blade of a drum cleaner 16.

The intermediate transfer belt 20 is stretched around a driving roll 21, a driven roll 22, a tension roll 23, and a backup roll 24, and is rotated at a constant speed in the direction of arrow D by the rotational power of the driving roll 21. It is supposed to. Each of the rolls 21 to 24 is rotatably supported by a bearing. Reference numeral 25 in the drawing denotes a belt cleaner for cleaning the intermediate transfer belt 20.

The toner image multiplex-transferred onto the intermediate transfer belt 20 is conveyed to a secondary transfer position facing a secondary transfer roll 30 disposed opposite to the backup roll 24. Then, the toner image on the intermediate transfer belt 20 is sent out from the storage tray 31 according to the image forming and transfer timing of the toner image,
3 and a recording sheet P conveyed to a secondary transfer position through a sheet conveying path on which a registration roll 34 and the like are arranged.
Secondary transfer is performed electrostatically. A dashed line with an arrow in FIG. 1 indicates a conveyance path of the recording sheet. Then, the recording sheet P on which the toner image has been transferred is placed on a roll nip type fixing device 35.
After passing through the nip portion between the heating roll 36 and the pressure roll 37 to perform a heat fixing process of the toner image, the toner image is discharged by a discharge roll 38 to a discharge tray 39 or the like outside the apparatus main body. It has become. Through the above process, a full-color image is formed on the recording sheet P.

As shown in FIG. 2 and the like, each of the developing devices 14 in the four image forming units 10
Y, 14M, 14C, 14K developing rolls (rotating parts)
Are rotated by one electric motor.

FIG. 2 is a schematic diagram showing the entire configuration of the drive mechanism. This drive mechanism transmits the rotational power of an electric motor 40 as a rotational drive source to a rotating shaft 45 for rotating the developing rolls of the four developing devices 14 by a belt drive transmitting mechanism 50 and the belt is wound around the belt. Is switched by the belt moving mechanism 60 so that the object of the rotating shaft 45 for transmitting the rotating power can be selected.

The belt drive transmission mechanism 50 basically connects the timing belt 51 to the drive shaft 4 of the electric motor 40.
1, a fixed pulley 42 fixedly mounted on a rotating shaft 45 of each developing device 14, and a driven idler pulley 47 rotatably supported on a shaft (not shown). The rotation power of the electric motor 40 is supplied to the four developing devices 14 via the belt 51.
Can be equally transmitted to the respective rotating shafts 45. The electric motor 40 rotates forward in the direction of arrow A.

The belt moving mechanism 60 is connected to the rotating shaft 45 of the magenta and cyan developing devices 14M and 14C.
It is constituted by a tensioner movably arranged in the vertical direction between M and 45C. In the tensioner 60, two driven idle pulleys 62 and 63 for hanging the timing belt 51 are rotatably arranged at intervals on a support plate 61 supported movably in the vertical direction. It consists of a structure.

When the tensioner 60 moves to the lower position H1 side, as shown in FIG.
The timing belt 5 is driven by the upper driven idler pulley 62.
1 is retracted downward between the rotating shafts 45M and 45C.
1 (fixed pulley 41) and each rotating shaft 45 of the four developing devices
(Fixed pulley 46) is held around all of them. Conversely, when the tensioner 60 moves to the upper position H2 side, as shown in FIG. 2B, the timing belt 51 is lifted upward by the lower driven idler pulley 63 between the rotation shafts 45M and 45C. Thereby, the timing belt 51 is wrapped around only the rotating shaft 41 (the fixed pulley 41 thereof) and the rotating shaft 45K of the black developing device, and is separated from the other rotating shafts 45Y, 45M, and 45C. It is designed to keep it in a state where

Here, the means for moving the tensioner 60, which is the belt moving mechanism, in the vertical direction is not particularly limited and can be arbitrarily selected. In this embodiment, the following moving means is applied. ing.

FIGS. 3A and 3B show a moving device of the tensioner 60. FIG. 3A is a front view and FIG. 3B is a top view. In this moving device, a tensioner 60 is attached to a distal end portion of a link 66 fixed to a rotatable support shaft 65, and the link 66 is vertically swung by using the rotational power of the electric motor 40. The tensioner 60 is moved to the lower position H1 and the upper position H2.

That is, a protrusion (stud) 61a on the support plate 61 of the tensioner 60 is movably fitted into a long hole space 66a formed inside the distal end of the link 66, and the protrusion 61a is inserted into the long hole. The tensioner 60 is attached to the distal end of the link 66 by being kept constantly biased toward the distal end of the link by the spring 66b in the space 66a. On the other hand, in addition to the fixed pulley 42, a fixed pulley 43 for a tensioner is arranged and mounted on the drive shaft 41 of the electric motor 40, and an idle pulley 67 with an electromagnetic clutch 68 is rotatably mounted on the support shaft 65 of the link 66. By rotating a belt 69 between the fixed pulley 43 on the drive shaft 41 side and the idle pulley 67 on the support shaft 65 side, the rotational power during rotation of the electric motor 40 is transmitted to the idle pulley 67. In the case of this moving device, the timing belt 5
A one-way clutch 44 is attached to the fixed pulley 42 on which the gear 1 is hung, and the idler rotates relative to the drive shaft 41 when the electric motor 40 rotates in the reverse direction.

The moving mechanism is an electric motor 40
Is rotated in the reverse direction (rotation in the direction of arrow B) and the electromagnetic clutch 68 is engaged, the rotational power during the reverse rotation of the electric motor 40 is transmitted to the support shaft 65 so that the link 6 is rotated.
6 swings from the lower position H1 to the upper position H2,
Conversely, when the electric motor 40 is rotated forward (rotation in the direction of arrow A) and the electromagnetic clutch 68 is engaged, the rotational power during the forward rotation of the electric motor 40 is transmitted to the support shaft 65 so that the link 67 is moved forward. It swings in the opposite direction to the case and moves from the upper position H2 to the lower position H1. At this time, the electromagnetic clutch 68
It is designed to connect only when rocking. When the link 66 is at the lower position H1 and the upper position H2, the tensioner 6
0 is applied by the tension of the timing belt 69,
Since it is pressed by the spring 66b in the link 66, it does not move even if the electromagnetic clutch 68 is not connected, and stops at any of the positions H1 and H2 described above.

Next, the operation of the driving mechanism will be described.

First, when all four developing devices 14 are to be rotationally driven, such as when a full-color image is formed, the tensioner 60, which is a belt moving mechanism, is moved to the lower position H1 by the moving device. The belts 51 are connected to the rotating shafts 45Y of all the developing devices 14,
45, 45C, and 45K (fixed pulley 46 thereof) and are held in a state of being wound around (FIG. 3A). Thereby, the electric motor 4
Since the rotational power in the direction of the arrow A of 0 is transmitted equally to the four rotary shafts 45 by the timing belt 51, the rotary shafts 45Y, 45M, 45C, and 45K all rotate in the same direction (FIG. 2A). In this way, the developing rolls of the four developing devices 14 are driven to rotate by one electric motor 40, so that the developing work of each color can be performed.

On the other hand, when a part of the four developing devices (the black developing device 14B in this embodiment) is to be driven to rotate, such as when a monochrome image is formed, the tensioner 60 as a belt moving mechanism is used. The timing belt 51 is moved to the upper position H2 by the moving device.
Is held around the (only the fixed pulley 46 of) the rotating shaft 45K of the black developing device 14B (FIG. 3B).
As a result, since the rotational power of the electric motor 40 in the direction of arrow A is transmitted to only the rotating shaft 45K by the timing belt 51, only the rotating shaft 45K rotates (FIG. 2).
b). In this way, only the developing roller of the developing device 14K for black among the four developing devices 14 is driven to rotate, and only the developing operation of the black color can be performed.

As described above, according to the printer of the present embodiment, the developing rolls of the four developing devices 14 can be simultaneously driven to rotate by the single electric motor 40, and the tensioner 60 of the belt moving mechanism in the driving mechanism is used. By switching the state in which the timing belt 51 is wound, only a part of the developing devices 14K can be rotationally driven. In addition, when only a part of the developing devices 14K is driven to rotate, the other developing devices 14Y and 14K that are stopped without being driven to rotate are stopped.
Since there is no need to move the M and 14C to the retracted position and the like, the four developing devices can be securely fixed to the frame or the like of the apparatus main body, and as a result, a shift in the developing position and a drive transmission mechanism occur. The transmission of the vibrating vibration to the developing device can be suppressed. In this printer, an electromagnetic clutch 68 is used in the moving device of the tensioner 60. However, the electromagnetic clutch 68 requires a smaller torque (capacity) than the electromagnetic clutch used for the drive transmission mechanism, and therefore, increases the cost. It is possible to avoid.

[Embodiment 2] This embodiment is an embodiment to which the present invention (second invention) is applied, except that a drive mechanism as shown in FIG. 4 is applied as a drive mechanism for four developing devices. Has the same configuration as in the first embodiment.

That is, the drive mechanism for the four developing devices in the second embodiment transmits the rotational power of the electric motor 40 to the rotating shafts 45 of the four developing devices 14 by the belt drive transmission mechanism 55 and the belt drive transmission mechanism 55. Is switched by the belt displacement mechanism 70 to select a target of the rotary shaft 45 for transmitting the rotational power.

The belt drive transmission mechanism 55 includes three developing devices 14Y and 14 having a time to stop the rotation.
An idle pulley (first idle pulley) 57 having a narrow width (a first fixed pulley) 56 having a narrow width (wider than the width of the belt 51; the same applies to the following) on the rotation shafts 46Y, 46M, 46C of M and 14C. Are mounted side by side, and a pulley (a fixed pulley 42 of the drive shaft 41 of the electric motor 40, a rotating shaft 4 of the developing device 14K)
As a 5K fixed pulley 46 and a driven idler pulley 47), a wide fixed pulley (width approximately twice as large as the width of the belt 51) substantially equal to the total width of the first fixed pulley 56 and the first idler pulley 57 (the second pulley 57). It has the same configuration as the belt drive transmission mechanism 50 in the first embodiment, except that a (two fixed pulleys) 58 are used.

Further, the belt displacement mechanism 70 is shown in FIG.
As shown in FIG.
It is constituted by a belt displacement pulley disposed so as to be movable in the axial direction between the rotation shafts 45M and 45C of the M and 14C. The belt displacement pulley 70
Has a structure in which a pulley having a width substantially equivalent to the width of the timing belt 51 is supported so as to be axially displaceable and rotatable.

The belt displacement pulley 70 is
4B, the entire timing belt 51 is displaced toward the axially rearward position J1 as shown in FIG. 4B. The fixed pulley 56 and all the wide fixed pulleys 58 are held in a state of being wound around. On the contrary, when the belt displacement pulley 70 moves to the position of the shaft tip side J2, as shown in FIG.
The entirety of the timing belt 51 is displaced toward the shaft tip side position J2, so that the timing belt 51 is held in a state of being wrapped around all the narrow idle pulleys 57 and all the wide fixed pulleys 58. It has become.

Here, the means for moving the belt displacement pulley 70, which is the belt displacement mechanism, in the axial direction is not particularly limited and can be arbitrarily selected. In this embodiment, the following means are used. Has been applied.

FIG. 5 shows a device for moving the pulley 70 for belt displacement. FIG.
FIG. 7B is a diagram showing a state when moving to the side, and FIG. 7B is a diagram showing a state when moving to the shaft tip side position J2 side. The moving device is rotatably supported on a support shaft 76 attached to a support frame 75 so as to be rotatable and movable in the axial direction.
8, the shaft inner position J1 and the shaft tip position J2
And to move to.

That is, the belt displacement pulley 70 is rotatably supported on the support shaft 76 so as to be rotatable and movable in the axial direction thereof, and is elastically attached to the distal end side of the support shaft 76 by a spring 79. It is being rushed. On the other hand, the link mechanism 7
8, the arm 78a is rotatably supported by a support shaft 78b, and the arm tip 78c is arranged so as to abut the side surface of the pulley 70 to push the pulley 70 in the axial direction. The rear end portion 78d of the arm is disposed so as to be supported by the front end portion of the output shaft 77a of the solenoid 77. The moving mechanism is provided by a solenoid 77
Is OFF, the link mechanism 78 does not push the pulley 70, so that the pulley 70 is located at the shaft inner position J1. Conversely, when the solenoid 77 is ON, the link mechanism 78 is supported by the retracting operation of the output shaft 77a. Since the arm tip 78b pushes the pulley 70 in the direction of the base of the support shaft 76 by rotating about the shaft 78c, the pulley 70 is set to be located at the shaft tip side position J2.

Next, the operation of the drive mechanism according to the second embodiment will be described.

First, when all four developing devices 14 are to be driven to rotate, for example, when a full-color image is formed, a belt displacement pulley 70 serving as a belt displacement mechanism is used.
Is displaced to the shaft inner position J1 by the moving device,
The timing belt 51 is held around a narrow fixed pulley 56 and a wide fixed pulley 58 (FIG. 4).
b). As a result, the rotational power of the electric motor 40 in the direction of arrow A is fixed to the shafts by the timing belt 51, and the four rotary shafts 45Y, 45Y are fixed to the shafts.
Since they are equally transmitted to 45M, 45C, and 45K, all of the rotation shafts 45 rotate in the same direction (FIG. 4A).
Thus, the developing rolls of the four developing devices 14 are 1
The developing operation of each color can be performed by being rotationally driven by the two electric motors 40.

On the other hand, as in the case of forming a monochrome image, a part of the four developing devices (black developing device 14) is used.
When B) is to be rotationally driven, the belt displacement pulley 70, which is a belt displacement mechanism, is displaced to the shaft tip side position J2 by the moving device, and the timing belt 51 is moved to the narrow idle pulley 57 and the wide fixed pulley. It is held in a state of being looped around 58 (FIG. 4c). As a result, the rotational power of the electric motor 40 in the direction of arrow A is transmitted to only the rotary shaft 45K via the fixed pulley 58 fixed to the shaft by the timing belt 51, so that only the rotary shaft 45K rotates. Rotary shaft 45 to which idle pulley 56 is attached
No rotational power is transmitted to Y, 45M, and 45C because the idle pulley 56 idles. Therefore, only the developing roller of the black developing device 14K among the four developing devices 14 is driven to rotate, and only the black developing operation can be performed.

As described above, according to the printer of the second embodiment, the same effects as those of the first embodiment can be obtained.

[Embodiment 3] Embodiment 3 is an embodiment to which the present invention (third invention) is applied, and a driving mechanism as shown in FIGS. 6 and 7 is applied as a driving mechanism for four developing devices. Except for this, the configuration is the same as that of the first embodiment.

That is, the drive mechanism for the four developing devices in the third embodiment transmits the rotational power to the rotating shafts of the four developing devices by the two-system belt drive transmission mechanism 80 divided into two systems, and the belts thereof. The rotational power of the electric motor 40 is transmitted to two drive transmission shafts 81 and 82 provided in the drive transmission mechanism 80 by a gear drive transmission mechanism 90 composed of a gear train, and the gear train of the gear drive transmission mechanism 90 meshes with the gear train. The system of the belt drive transmission mechanism 80 for transmitting the rotational power from the electric motor 40 by switching the state by the gear displacement mechanism 100, and thus the object of the rotary shaft 45, can be selected.

As shown in FIGS. 6 and 7, the two-system belt drive transmission mechanism 80 includes a rotating shaft 45K of the black developing device 14K to be continuously rotated and the rotating shaft 45K.
A first system for transmitting a drive by a first timing belt 83 to a first drive transmission shaft 81 for transmitting rotational power to the first system;
Three developing devices 1 with time to stop the rotation power
The second timing belt 84 is used to transmit a drive between a rotation shaft 45 of each of the 4Y, 14M, and 14C and a second drive transmission shaft 82 that transmits rotational power to the rotation shaft 45. In the drawing, reference numeral 85 denotes a fixed pulley attached to the rotating shaft 45 of each developing device 14, 86 denotes a fixed pulley attached to the first drive transmission shaft 81, and 87 denotes a fixed pulley attached to the second drive transmission shaft 82. And 88 are idle pulleys for tension.

The gear drive transmission mechanism 90 is the same as that shown in FIG.
As shown in FIG. 5, the gear train is provided between the first drive transmission shaft 81 and the second drive transmission shaft 82 and the drive shaft 41 of the electric motor 40. This gear drive transmission mechanism 90
The gear train of the first drive transmission shaft 81 as shown in FIG.
A first gear 91 having a wide width (having a width exceeding about twice as large as a third gear described later, the same applies hereinafter) that meshes with a drive gear 91 fixedly attached to a drive shaft 41 attached to the second shaft;
A second gear 92 attached to the drive transmission shaft 82 and having a small width (having substantially the same width as a third gear described later);
A third gear 94 having a large width meshing with a driving gear 93 attached to the 0 driving shaft 41, and a fourth gear 95 capable of meshing with the first gear 91, the second gear 92 and the third gear 94 at the same time. Have been.

Further, the gear changing mechanism 100 can transmit the rotational power from the electric motor 40 to the first drive transmission shaft 81 and the second drive transmission shaft 82 at the same time, or can transmit only the first drive transmission shaft 81. In this embodiment, the fourth gear 95 of the gear drive transmission mechanism 90 is used.

That is, the fourth gear 95 is connected to the first gear 91
And a final gear that finally meshes with the second gear 92. The fourth gear 95 has a structure that can be displaced in the axial direction of the support shaft 96. And the gear change mechanism 100
By displacing the fourth gear 95 to the pulley side position K1, the fourth gear 95 is held in a state of meshing with the first gear 91 and the second gear 92 simultaneously (while still meshing with the second gear 94). (FIG. 6B), the fourth gear 95 is displaced to the shaft tip side position K2, whereby the fourth gear 9 is moved.
5 is kept engaged with the first gear 91 only (while remaining engaged with the second gear 94) (FIG. 6b). The means for moving the fourth gear 95 in the axial direction is not particularly limited as long as it can realize the movement. For example, the belt displacement pulley 70 in the second embodiment may be used. A moving device (FIG. 5) for displacing can likewise be applied.

Next, the operation of the driving mechanism according to the third embodiment will be described.

First, when all four developing devices 14 are to be rotationally driven, such as when a full-color image is formed, the fourth gear 95 is displaced to the pulley side position K1 by the gear change mechanism 100, and the fourth The gear 95 is held so as to mesh with the first gear 91 and the second gear 92 at the same time (FIG. 6B). Thus, the rotational power of the electric motor 40 in the direction of arrow A is transmitted to the first drive transmission shaft 81 and the second drive transmission shaft 82 via the gear train of the gear drive mechanism 90, and then each of the drive transmission shafts Since the rotation is transmitted from the transmission shafts 81 and 82 to the four rotation shafts 45Y, 45M, 45C and 45K via the first timing belt 83 and the second timing belt 84, the rotation shafts 45 rotate in the same direction (FIG. 6a). In this way, the developing rolls of the four developing devices 14 are driven to rotate by one electric motor 40, so that the developing work of each color can be performed.

On the other hand, a part of the four developing devices (the black developing device 14
When B) is to be driven to rotate, the gear change mechanism 100
As a result, the fourth gear 95 is displaced to the shaft tip portion side position K2, and the fourth gear 95 is held in a state of meshing only with the first gear 91 at the same time (FIG. 7B). Thereby, the electric motor 4
The rotation power in the direction of arrow A of 0 is first transmitted to only the first drive transmission shaft 81 via the gear train of the gear drive mechanism 90, and then the rotation shaft 45K is transmitted from the drive transmission shaft 81 via the first timing belt 83. Is transmitted only to the rotating shaft 45
Only K rotates. No rotational power is transmitted to the second drive transmission shaft 82 because the fourth gear 95 does not mesh with the second gear 92. Therefore, only the developing roller of the black developing device 14K among the four developing devices 14 is driven to rotate, and only the black developing operation can be performed.

As described above, according to the printer of the third embodiment, the same effects as those of the first embodiment can be obtained.

Embodiment 4 Embodiment 4 is an embodiment to which the present invention (fourth invention) is applied. The photosensitive drum 11K in the black image forming unit 10K, the fixing roll 36 in the fixing device 35, This embodiment has the same configuration as that of the first embodiment except that a drive mechanism as shown in FIG.

That is, the drive mechanism for the photosensitive drum 11K and the fixing roll 36 (37) in the fourth embodiment transmits the rotational power of the electric motor 40 as a rotational drive source to the photosensitive drum and the fixing roll by the gear drive transmission mechanism 110. In addition, the switching mechanism 1 of the switching drive transmission mechanism 120 is in a transmission state when the electric motor 40 rotates forward and is in a non-transmission state when the electric motor rotates reversely.
With 25, the transmission destination (target) of the rotational power can be selected.

The gear drive transmission mechanism 110 includes a drive gear 111 attached to the drive shaft 41 of the electric motor 40.
And a fifth gear 113 which is attached to a drum drive transmission shaft 112 for transmitting rotational power to the photosensitive drum 11K and meshes with the drive 111, and a roll drive transmission shaft 114 for transmitting rotational power to the fixing rolls 36 and 37. A sixth gear 115 meshing with the drive gear 111, a seventh gear 116 having a larger diameter than the sixth gear 115, and a passive gear 117 attached to the rotating shaft 39 of the fixing roll 36.

The switching mechanism 125 of the switching drive transmission mechanism 120 is constituted by a reverse rotation releasing type coupling 130 connecting between the drum drive transmission shaft 112 and the rotating shaft 118 of the photosensitive drum 11K. . The coupling 130 includes a first coupling 131 attached to the distal end of the drum drive transmission shaft 112 and a second coupling 132 attached to the distal end of the rotating shaft 118. 131, 132
Also, the projections 133 and 13 can be locked when the electric motor 40 rotates forward and unlocked when the electric motor 40 rotates reversely.
4 respectively. Also, the second coupling 13
Numeral 2 is slidably fitted to the rotating shaft 118 and is elastically supported by a spring 136 having one end fixed to a fixed ring body 135 fixed to the rotating shaft 118. Tip 118
When pushed from the side a, it can be displaced to the fixed ring body 135 side. Reference numeral 112a in FIG.
Is an insertion hole formed at the center of the drum drive transmission shaft 112 and into which the rotation shaft tip 118a of the photosensitive drum is inserted when the coupling 130 is connected. In addition, the first coupling 131 and the fixing ring 135 are connected to the fastening screw 13.
7 are fixed to the shafts 112 and 118, respectively.

In this embodiment, the protrusions 133, 1
Two projections 34 are formed symmetrically on the coupling opposing surfaces of the couplings 131 and 132. More specifically, the entirety is substantially trapezoidal in shape, and vertical surfaces 133a and 134a for locking are formed on one end, and inclined surfaces 133b and 134b for climbing over the protrusion are formed on the other end. It has a structure.

The couplings 131 and 132 are
The rotation shaft 118 of the photosensitive drum 11K is inserted into the insertion hole 112a on the drum drive transmission shaft 112 side, and each of the projections 13
When the coupling is turned in a direction E in which the vertical surfaces 133a and 134a of the third and 134 collide with each other (forward rotation direction in the coupling), as shown in FIG.
The vertical surfaces 133a, 134a of the third, 134 approach and collide with each other, and are locked, so that the couplings 131, 132 rotate integrally (FIG. 10b). On the other hand, when the coupling is turned in a direction F in which the inclined surfaces 133b and 134b of the projections 133 and 134 collide with each other (a reverse rotation direction in the coupling), as shown in FIG. 133b and 134b approach and collide with each other, climb over each other by sliding on an inclined surface, and the locked state is released, and the couplings 131 and 132 are released.
The members are unlocked and spin freely (Fig. 1
1c).

Next, the operation of the driving mechanism according to the fourth embodiment will be described.

First, when the photosensitive drum 11K and the fixing roller 36 (37) are to be driven to rotate simultaneously, such as during an image forming operation, the drive motor 40 rotates forward (rotates in the direction of arrow A) to drive the drum. Since the transmission shaft 112 rotates in a direction corresponding to the forward rotation direction E (FIG. 10a) of the coupling, the projections 133 and 134 of the coupling 130 (131, 132) collide with each other and are locked. As a result, the rotational power of the drum drive transmission shaft 112 is transmitted to the rotation shaft 118 via the coupling 130, so that the photosensitive drum 11K rotates (FIG. 8).
a). Further, when the drive motor 40 rotates forward, the rotation power is transmitted to the roll drive transmission shaft 114, and then the seventh power is transmitted.
Since the light is transmitted to the rotating shaft 49 via the gear 116, the fixing roll 36 also rotates (FIG. 8A).

On the other hand, when only the fixing roller 36 (37) is to be driven to rotate while the photosensitive drum 11K is stopped, such as when the power of the printer is turned on or at a predetermined time, the drive motor 40 rotates in the reverse direction (arrow). B) and the drum drive transmission shaft 112 rotates in a direction corresponding to the reverse forward rotation direction F (FIG. 11a) of the coupling, so that the projection 13 of the coupling 130 (131, 132) is rotated.
3 and 134 do not collide with each other and are in an unlocked state. As a result, the rotational power of the drum drive transmission shaft 112 is not transmitted to the rotation shaft 118 via the coupling 130, so that the photosensitive drum 11K does not rotate (FIG. 8B). On the other hand, since the rotating power is transmitted to the rotating shaft 49 through the gear drive transmitting mechanism 110 as in the case described above, only the fixing roll 36 rotates (FIG. 8B). However, the rotation direction of the fixing roll 36 at this time is opposite to that of the previous case.

As described above, according to the printer of the fourth embodiment, the photosensitive drum 11K and the fixing roll 36 (37) can be simultaneously driven to rotate by one electric motor 40, and the electric motor 40 is rotated in the reverse direction. By setting the coupling 130, which is the switching mechanism 125 of the switching drive transmission mechanism 120, to the non-locked state, only the fixing roll 36 (37) can be rotationally driven. In addition, when only the fixing roll is driven to rotate, it is not necessary to move the photosensitive drum 11K, which is stopped without being driven to rotate, to a retreat position or the like. In addition, when only the fixing roll is driven to rotate idly to improve the fixability, the photosensitive drum does not rotate idly, so that the surface of the photosensitive drum is not worn by the sliding contact of the cleaning blade.

[Embodiment 5] Embodiment 5 is another embodiment to which the present invention (fourth invention) is applied. As a driving mechanism for the photosensitive drum 11K and the fixing roll 36, a driving mechanism as shown in FIG. The configuration is the same as that of the fourth embodiment except that is applied.

That is, the drive mechanism for the photosensitive drum and the fixing roll in the fifth embodiment transmits the rotational power of the electric motor 40 to the photosensitive drum and the fixing roll by the gear drive transmission mechanism 140 and the inside of the gear drive transmission mechanism 140. The one-way clutch 150, which is arranged at a predetermined position, is in a transmission state when the electric motor 40 rotates forward and is in a non-transmission state when the electric motor rotates reversely.
Thus, the transmission destination (target) of the rotational power can be selected. The one-way clutch 150 functions as the switching mechanism 125 of the switching drive transmission mechanism 120, and is applied instead of the coupling 130 as the switching mechanism 125 in the fourth embodiment.

The gear drive transmission mechanism 140 includes a drive gear 141 attached to a drive shaft 41 of the electric motor 40.
And the drive gear 141, and the photosensitive drum 11K
Passive gear 143 for drum attached to rotary shaft 142
An eighth gear 145 attached to a roll drive transmission shaft 144 for transmitting rotational power to the fixing roll 36 (37) and meshing with the drive gear 141; and a roll drive transmission shaft 144.
And the ninth gear 1 having a larger diameter than the eighth gear 145.
46 and the tenth gear 14 smaller in diameter than the eighth gear 145
7, a wide passive gear 148 for the roll attached to the rotating shaft 39 of the fixing roll 36 (37), and a small eleventh gear (idler gear) 149 meshing with the tenth gear 147 and the passive gear 148 for the roll. It is configured.
Therefore, the drive transmission mechanism 140 includes an A-system gear train in which the rotational power of the roll drive transmission 144 is transmitted from the ninth gear 146 to the rotary shaft 39 via the roll passive gear 148, and the rotational power of the A-system gear train. Tenth gear 147 to eleventh
After passing through the gear 149, there is a B-system gear train transmitted to the rotating shaft 39 via the roll passive gear 148.

The one-way clutch 150 serving as the switching mechanism 125 has an A-type one-way clutch 150A which is in a transmission state when the electric motor 40 rotates forward and is in a non-transmission state when the electric motor 40 rotates reversely.
There is a B-type one-way clutch 150B which is in a non-transmission state during normal rotation and is in a transmission state during reverse rotation. And A type one-way clutch 150A
Are attached to the passive gear 143 and the ninth gear 146 for the drum, and the B-type one-way clutch 1
50B is attached to the tenth gear 147.

Next, the operation of the driving mechanism according to the fifth embodiment will be described.

First, the photosensitive drum 11K and the fixing roll 36
When (37) is to be driven to rotate at the same time, the electric motor 40 rotates forward (rotates in the direction of arrow A) and the passive gear 14
The one-way clutch 150 </ b> A as the switching mechanism 125 attached to 3 is in the transmission state. As a result, the rotational power is transmitted to the rotating shaft 142 via the driving gear 141 and the passive gear 143, so that the photosensitive drum 11K rotates (FIG. 12A). The forward rotation of the electric motor 40 causes the one-way clutch 150A attached to the ninth gear 146 to be in the transmission state, while the tenth gear 147
The one-way clutch 150B attached to the non-transmission state is in a non-transmission state. As a result, the rotating power is transmitted to the rotating shaft 3 via the ninth gear 146, which is the gear train of the A system, and the passive gear 148.
9, the fixing roll 36 also rotates (see FIG. 1).
2a). At this time, the tenth gear 147 idles with respect to the roll drive transmission 144.

On the other hand, when only the fixing roller 36 (37) is to be rotationally driven while the photosensitive drum 11K is stopped, the driving motor 40 is rotated in the reverse direction (rotated in the direction of arrow B) and attached to the passive gear 143. Since the one-way clutch 150A is in the non-transmission state, the photosensitive drum 11K does not rotate (FIG. 12B). Further, the one-way clutch 150A attached to the ninth gear 146 is brought into a non-transmission state by the reverse rotation of the electric motor 40, while the one-way clutch 150B attached to the tenth gear 147 is brought into a transmission state. Is transmitted to the rotation shaft 39 via the tenth gear 147 and the eleventh gear 149, which are the gear train of the B system, via the passive roller gear 148.
Thereby, only the fixing roll 36 rotates (FIG. 12).
b). At this time, the tenth gear 147 is the roll drive transmission 1
It will idle with respect to 44. The rotational power is supplied to the tenth gear 147 and the first gear 147 having a smaller diameter than the ninth gear 146.
The transmission is performed at a lower speed than in the case of the gear train of the A system (rotational speed at normal times) to the rotating shaft 39 via one gear 149, so that the fixing roll 36 rotates at a lower speed than at normal times.
Note that the rotation direction at this time is the same as that in the case where the photosensitive drum is driven to rotate.

As described above, according to the printer of the fifth embodiment, the same effects as those of the fourth embodiment can be obtained. In particular, in the fifth embodiment, the fixing roll 36 (37)
In the case of rotating only the fixing roller, the fixing roller rotates at a lower speed than the normal rotation speed.
7) can be warmed. The rotation direction at this time is the same as that in the case of rotating the photosensitive drum together with the photosensitive drum. This is effective when a member that comes into contact with the fixing roll 36 and the like is arranged and it is not desired to rotate in the reverse direction.

[Embodiment 6] This embodiment 6 is another embodiment to which the present invention (fourth invention) is applied. As a drive mechanism for the photosensitive drum 11K and the fixing roll 36, a drive mechanism as shown in FIG. The configuration is the same as that of the fourth embodiment except that is applied.

That is, the drive mechanism for the photosensitive drum and the fixing roll in the sixth embodiment is a gear drive transmission mechanism for transmitting the rotational power of the electric motor 40 to the photosensitive drum and the fixing roll. Instead, a gear drive transmission mechanism 160 using a planetary gear 161 is applied. The transmission destination (target) of the rotational power is selected by attaching the same one-way clutch 150A to the passive gear for drum as in the fifth embodiment.

As shown in FIGS. 13 and 14, the gear drive transmission mechanism 160 does not attach the one-way clutches 150A and 150B to the ninth gear 146 and the tenth gear 147 attached to the roll drive transmission shaft 144, and The configuration is the same as that of the drive transmission mechanism 140 in the fifth embodiment, except that a first gear train for normal speed transmission and a second gear train for deceleration transmission are configured using the gear 161.

Of these, the planetary gear 161 has three gears 161a, 161b, and 316 having the same diameter on a support shaft 163 loosely fitted in a guide slot 162 for a planetary gear formed on a support frame of a gear box (not shown). 161c is fixedly attached. The gear 161a is connected to the ninth gear.
The gear 146 meshes with the gear 161b, the gear 161b meshes with the roll passive gear 148, and the gear 161c meshes with the tenth gear 1
An eleventh gear 149 meshing with the gear 47 can be meshed. And this planetary gear 161
At the time of forward rotation of the electric motor 40, the gear 161a is in a state of meshing with the ninth gear 146 without fail.
Since 3 is located below the guide slot 162, it forms a first gear train for normal speed transmission (FIG. 14a). On the other hand, when the electric motor 40 rotates in the reverse direction, the gear 161c is securely engaged with the eleventh gear 149, and the support shaft 163 is located above the guide elongated hole 162. A gear train is formed (FIG. 14b).

Next, the operation of the driving mechanism according to the sixth embodiment will be described.

First, the photosensitive drum 11K and the fixing roll 36
When (37) is to be driven to rotate at the same time, the electric motor 40 rotates forward (rotates in the direction of arrow A) and the passive gear 14
The one-way clutch 150A as the switching mechanism 125 attached to the transmission gear 3 is in a transmission state, and its rotational power is transmitted to the rotary shaft 142 via the drive gear 141 and the passive gear 143, so that the photosensitive drum 11K rotates (FIG. 13).
a). Further, by the forward rotation of the electric motor 40, the support shaft 1623 of the planetary gear 161 is located at a position below the guide elongated hole 162, and the first gear train is in a transmission state. At this time, the second gear train is in a non-transmission state. As a result, the ninth gear 146 of the first gear train and the planetary gear 1
61a and 161b and the passive shaft 148 through the rotating shaft 39
, The fixing roll 36 also rotates at normal speed (FIG. 13A).

On the other hand, when only the fixing roll 36 (37) is to be rotationally driven while the photosensitive drum 11K is stopped, the driving motor 40 is rotated in the reverse direction (rotated in the direction of arrow B) and attached to the passive gear 143. Since the one-way clutch 150A is in the non-transmission state, the photosensitive drum 11K does not rotate (FIG. 13B). In addition, by the reverse rotation of the electric motor 40, the support shaft 1623 of the planetary gear 161 is located above the guide slot 162, and the second gear train is in the transmission state. At this time, the first gear train is in a non-transmission state. As a result, the rotation power is changed to the tenth gear 146 that is the second gear train.
And the eleventh gear 149 and the planetary gears 161c, 161b
Is transmitted to the rotating shaft 39 via the passive gear 148, so that only the fixing roll 36 rotates (FIG. 13B). At this time, the rotational power is transmitted to the rotating shaft 39 by the second gear train at a speed lower than that in the case of the first gear (normal rotation speed). Rotate. Note that the rotation direction at this time is the same as the case where the photosensitive drum is driven to rotate.

As described above, according to the printer of the sixth embodiment, the same effects as those of the fifth embodiment can be obtained.

[Embodiment 7] Embodiment 7 is an embodiment to which the present invention (fifth invention) is applied. The photosensitive drum 11K in the black image forming unit 10K, the fixing roll 36 in the fixing device 35, It has the same configuration as that of the first embodiment except that a drive mechanism as shown in FIG.

That is, the drive mechanism for the photosensitive drum 11K and the fixing roll 36 (37) in the seventh embodiment transmits the rotational power of the electric motor 40 as a rotational drive source to the photosensitive drum and the fixing roll by the gear drive transmission mechanism 170. At the same time, the centrifugal clutch 180 is in a transmission state when the electric motor 40 is rotating at a normal speed, and is in a non-transmission state when the electric motor is rotating at a low speed.
Into the gear drive transmission mechanism 170,
The transmission destination (target) of the rotational power can be selected.

The gear drive transmission mechanism 170 includes a drive gear 171 attached to the drive shaft 41 of the electric motor 40.
And a fifteenth gear 173 and a fifteenth gear 174 attached to a drum drive transmission shaft 172 for transmitting rotational power to the photosensitive drum 11K and meshing with the drive gear 171, and a fifteenth gear attached to the rotating shaft 175 of the photosensitive drum 11K. A sixteenth gear 176 meshing with the fixing roller 174;
Roll drive transmission shaft 17 for transmitting rotational power to (37)
7, a 17th gear 178 meshing with the drive gear 171, and an 18th gear 179 having a larger diameter than the 17th gear.
And a passive gear 181 attached to the rotating shaft 39 of the fixing roll 36.

The centrifugal clutch 180 is attached to the fifteenth gear 173 of the gear drive transmission mechanism 170. When the electric motor 40 rotates at a normal speed, the clutch is connected to transfer the rotational power to the drive transmission shaft 17 for the drum.
2, the clutch is disengaged when the electric motor rotates at a low speed, and the rotational power is not transmitted to the drum drive transmission shaft 172.

Next, the operation of the driving mechanism according to the fifth embodiment will be described.

First, the photosensitive drum 11K and the fixing roll 36
When (37) is to be driven to rotate at the same time, the electric motor 40 rotates forward (rotates in the direction of arrow A) at a normal speed, and the centrifugal clutch 180 enters the transmission state. As a result, the rotational power at the normal speed is transmitted to the drum drive transmission shaft 172 and transmitted to the rotation shaft 175 via the fifteenth gear 174 and the passive gear 176, so that the photosensitive drum 11K rotates at the normal speed. (FIG. 15a). The electric motor 4
The rotation at the normal speed is transmitted to the rotating shaft 39 via each gear train which is the gear drive transmission mechanism 170 by the forward rotation at the normal speed of 0, so that the fixing roll 36 also rotates at the normal speed. (FIG. 15a).

On the other hand, when only the fixing roller 36 (37) is to be rotationally driven while the photosensitive drum 11K is stopped, the driving motor 40 rotates forward and backward at a low speed (rotates in the direction of the arrow AA) to rotate the passive gear 143. Since the centrifugal clutch 180 attached to the photosensitive drum 11 is in the non-transmission state, the photosensitive drum 11
K does not rotate (FIG. 15b). In addition, the forward and reverse rotation of the electric motor 40 at low speed causes the low-speed rotation power to be transmitted to the rotation shaft 39 via each gear train that is the gear drive transmission mechanism 170, so that only the fixing roll 36 is rotated. It rotates at a lower speed than normal speed (FIG. 15b).

As described above, according to the printer of the sixth embodiment, the same effects as those of the fifth embodiment can be obtained.

[Other Embodiments] The respective drive mechanisms in Embodiments 1 to 7 can be used in appropriate combinations.

[0103]

As described above, according to the image forming apparatus of the present invention, a part of the drive transmission mechanism for transmitting the rotational power of the rotary drive source to the rotating parts is operated or the rotary drive source is simultaneously operated. By simply reversing the rotation of, only a part of the plurality of rotating components in the structure for rotating a plurality of rotating components by one rotation driving source can be simply and reliably rotated. . In addition, at this time, there is no need to displace the component itself, and it is not necessary to use an expensive component, so that there is no unnecessary cost increase.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a main part of an image forming apparatus according to a first embodiment.

FIG. 2 is an explanatory diagram illustrating a configuration of a driving mechanism for developing rollers of four developing devices according to the first embodiment.

FIG. 3 is an explanatory view showing a moving device of the belt moving mechanism of FIG. 2;

FIG. 4 is an explanatory diagram illustrating a configuration of a drive mechanism for developing rollers of four developing devices according to a second embodiment.

FIG. 5 is an explanatory view showing a moving device of the belt displacement mechanism of FIG. 4;

FIG. 6 is an explanatory diagram showing a configuration (when all are driven) of a driving mechanism for developing rolls of four developing devices in a third embodiment.

FIG. 7 is an explanatory diagram showing a configuration (when driving a part) of the drive mechanism of FIG. 6;

FIG. 8 is an explanatory diagram showing a configuration of a drive mechanism for a photosensitive drum and a fixing roll according to a fourth embodiment.

FIG. 9 is an explanatory view showing a coupling used in the drive mechanism of FIG. 8;

FIG. 10 is an explanatory view when the coupling of FIG. 9 is locked.

11 is an explanatory diagram when the coupling of FIG. 9 is in a non-locked state.

FIG. 12 is an explanatory diagram showing a configuration of a drive mechanism for a photosensitive drum and a fixing roll in a fifth embodiment.

FIG. 13 is an explanatory diagram showing a configuration of a drive mechanism for a photosensitive drum and a fixing roll according to a sixth embodiment.

FIG. 14 is an explanatory view showing the operation of a planetary gear used in the drive mechanism of FIG.

FIG. 15 is an explanatory diagram illustrating a configuration of a drive mechanism for a photosensitive drum and a fixing roll according to a seventh embodiment.

[Explanation of symbols]

11K: photosensitive drum (rotary component), 40: electric motor (rotary drive source), 41: drive shaft, 45: rotary shaft of developing device (rotary shaft of rotary component), 50: belt drive transmission mechanism,
51: timing belt, 55: belt drive transmission mechanism,
Reference numeral 60: tensioner (belt displacement mechanism), 70: belt displacement pulley (belt displacement mechanism), 90: gear drive transmission mechanism, 95: fourth gear (final gear), 100: gear displacement mechanism, 120: switchable drive transmission Mechanism: 125: switching mechanism, 130: coupling (switching mechanism), 150: one-way clutch (switching mechanism), 160: planetary gear (switching mechanism), 180: centrifugal clutch, A: forward rotation direction, B:
Reverse rotation direction.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G03G 21/00 350 G03G 15/08 507H (72) Inventor Mitsuaki Kuroda 2274 Hongo, Ebina City, Kanagawa Prefecture, Fuji Zero (72) Inventor Yukitomo Shigemori 2274 Hongo, Ebina-shi, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Inventor Seiichi Takayama 2274 Hongo, Ebina-shi, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Invention Person Naoto Nishi 2274 Hongo, Ebina City, Kanagawa Prefecture, within Fuji Xerox Co., Ltd. (72) Inventor Norio Hokari 2274 Hongo, Ebina City, Kanagawa Prefecture, within Fuji Xerox Co., Ltd. (72) Inventor Takashi Hoshino, Hongo, Ebina City, Kanagawa Prefecture 2274, Fuji Xerox Co., Ltd. (72) Inventor Susumu Yamashina Kana 2274 Hongo, Ebina-shi, Prefecture, Fuji Xerox Co., Ltd. (72) Inventor Kozo Tagawa 2274, Hongo, Ebina-shi, Kanagawa Prefecture, Fuji Xerox Co., Ltd. Inside Xerox Corporation (72) Inventor Yoshihiko Mitamura 2274 Hongo, Ebina-shi, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Inventor Satoshi Fukada 2274 Hongo, Ebina-shi, Kanagawa Prefecture, Fuji Xerox Co., Ltd. Inventor Teruyo Tatsuzaki 2274 Hongo, Ebina-shi, Kanagawa Prefecture, inside Fuji Xerox Co., Ltd. (72) Inventor Shinichi Kanaya 2274, Hongo, Ebina-shi, Kanagawa Prefecture, Fuji Xerox Co., Ltd. CG03 2H071 BA42 CA01 CA05 DA08 DA26 DA27 2H077 AD06 BA03 BA10 3J049 AA01 AB03 BB05 BB08 BD02 BH10 BH20 CA10

Claims (8)

[Claims] 1. A plurality of rotating parts constituting a part of an apparatus, and a rotary power for rotating the plurality of rotating parts is output.
A rotary drive source, and a drive capable of simultaneously transmitting the rotational power of the rotary drive source to the plurality of rotary components by wrapping a belt between the drive shaft of the rotary drive source and each rotary shaft of the plurality of rotary components. A transmission mechanism, and a belt of the drive transmission mechanism is moved in a predetermined direction and held in a state of being wound around all of the plurality of rotating parts and a state of being wound around only a part of the plurality of rotating parts, respectively. An image forming apparatus, comprising: a switching belt moving mechanism. 2. A plurality of rotating parts constituting a part of an apparatus, and a rotating power for rotating the plurality of rotating parts.
A rotating drive source, and a mechanism capable of simultaneously transmitting the rotational power of the rotary drive source to the plurality of rotary components by wrapping a belt between the drive shaft of the rotary drive source and each rotary shaft of the plurality of rotary components. And
A first fixed pulley having a small width and a first fixed pulley, which are attached side by side to a drive shaft of the rotary drive source and a rotary shaft of a stationary rotary component having a time to stop rotation among the rotary components;
A second fixed pulley having a wide width substantially corresponding to a total width of the first fixed pulley and the first idle pulley, which is attached to a rotating shaft of a continuous rotating component that continues rotation, which is the remaining rotating component, which is an idle pulley. And a state in which the belt of the drive transmission mechanism is axially displaced and wrapped around the first fixed pulley and the second fixed pulley, and wrapped around the first idle pulley and the second fixed pulley. An image forming apparatus comprising: a belt displacing mechanism that switches to hold the state. 3. A plurality of rotating parts constituting a part of the apparatus, and a rotary power for rotating the plurality of rotating parts is output.
Rotating drive sources, a wide first gear attached to a first drive transmission shaft that transmits rotational power to a rotating shaft of a continuous rotating component that continues to rotate among the rotating components, and the remaining rotating components A second gear having a small width attached to a second drive transmission shaft for transmitting rotational power to a rotation shaft of a stop type rotary component having a time to stop rotation, the first gear and the second gear, and the rotation A gear train composed of a plurality of gears arranged to be interposed between a third gear attached to the drive shaft of the drive source and transmitting the rotational power of the rotary drive source to the first gear and the second gear; A drive transmission mechanism to be used, and a final gear that finally meshes with the first gear and the second gear in the gear train of the drive transmission mechanism is axially displaceable, and the final gear is axially displaced. And the first gear and An image forming apparatus characterized by comprising a gear shift mechanism for switching to hold respectively to the state meshing with the second gear and the state of meshing only with the first gear. 4. A plurality of rotating parts constituting a part of an apparatus, and 1 for outputting rotational power for rotating the plurality of rotating parts.
A rotary drive source, a mechanism capable of transmitting the rotational power of the rotary drive source to the plurality of rotary components, and a stop type rotary component having a time to stop among the rotary drive source and the multiple rotary components. And a switching mechanism for maintaining a state in which rotational power is transmitted when the rotary drive source is rotating forward while maintaining a state in which rotary power is not transmitted when the rotary drive source is rotating reversely. An image forming apparatus, comprising: an image forming apparatus; 5. The apparatus according to claim 4, wherein the switching mechanism of the switchable drive transmission mechanism is configured to connect a drive transmission shaft to which rotational power of the rotary drive source is transmitted and a rotary shaft of the stop type rotary component. In the meantime, when the rotary drive source rotates forward, the power is locked and the rotational power is transmitted. On the other hand, when the rotary drive source is rotated reversely, the lock is released and the protrusion is unlocked. An image forming apparatus having a configuration in which coupling is performed by coupling. 6. The stationary rotary part according to claim 4, wherein a switching mechanism of the switching drive transmission mechanism meshes with a gear attached to a drive transmission shaft to which the rotational power of the rotary drive source is transmitted. The gear attached to the rotating shaft is connected to the rotating shaft via a one-way clutch that is in a transmission state when the rotation driving source rotates forward, and is in a non-transmission state when the rotation driving source rotates reversely. An image forming apparatus comprising: 7. The apparatus according to claim 4, wherein the switching-type drive transmission mechanism includes a gear attached to a drive transmission shaft to which rotational power of the rotary drive source is transmitted, and a rotation that is not the stop-type rotary component. A first gear train that transmits the rotational power at a normal speed during normal rotation of the rotary drive source and a gear attached to the rotary shaft of the continuous rotary component that continuously rotates the rotary drive source. An image forming apparatus having a configuration in which a second gear train for transmitting the rotation power at a speed lower than a normal speed is provided. 8. A plurality of rotating parts constituting a part of the apparatus, and a rotating power for rotating the plurality of rotating parts is output.
A rotary drive source, a mechanism capable of transmitting the rotational power of the rotary drive source to the plurality of rotary components, and a stop type rotary component having a time to stop among the rotary drive source and the multiple rotary components. During rotation of the rotary drive source at normal speed, the clutch is connected by centrifugal force and the rotary power is transmitted, while at a low speed lower than the normal speed of the rotary drive source. An image forming apparatus comprising: a drive transmission mechanism interposed with a centrifugal clutch that is in a state in which a clutch is disengaged and rotation power is not transmitted during rotation.