JP2569062B2 - Developing device switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an image forming machine such as an electrostatic copying machine or a facsimile machine, in which a developing device detachable from the machine can be moved to and away from the photoreceptor. 2. Description of the Related Art Conventionally, as a developing device provided in such an image forming machine, a developing device having different colors around a photoreceptor rotating in one direction. Two developing units containing the developer are provided, and these developing units are selectively operated to visualize the electrostatic latent image formed on the surface of the photoconductor into a color corresponding to the selected developing unit. (See, for example, JP-A-61-201272).

That is, the developing device disclosed in the above publication is configured such that a developing device is guided by a guide member so as to be movable toward and away from the photosensitive member, and is switched between a developable state and a non-developable state. It is simplified.

By the way, usually, a developing device is provided detachably with respect to the main body of the machine for exchanging a developing color or the like, and further uses a solenoid and a link mechanism to switch between a developable state and a non-developable state ( In the above publication, a motor and a cam mechanism are used. However, when the developing device is replaced, if the developing device is not correctly set on the guide member or the like, the motor or the like switches only in one direction during the subsequent switching operation. And a lock state may occur in the cam mechanism.

That is, if the switching operation is performed in a state where the setting of the developing device is defective, even if the motor or the like is driven for a certain period of time or more, the switching is not completed, so that the image forming machine becomes unusable, and Since it is in a state, it falls into a situation where a service man is called for repairs,
It is inconvenient.

Furthermore, in recent years, when the photoconductor and the developing device are kept in contact with each other for a long time, the surface of the photoconductor at this contact portion is crystallized, and the charging characteristics are changed, which results in uneven density. Therefore, even in an image forming apparatus provided with only one developing device, an attempt has been made to configure the developing device so that the developing device can be separated from the photoreceptor or can be detached and replaced. Even in such a developing device, if the developing device is not correctly set to the machine body, the same problem as described above will be exhibited.

(Object of the Invention) The present invention is to solve the above-mentioned problem, and in a device in which a detachable developing device is switched between a developable state and a non-developable state by moving the detachable developing device toward and away from the photoreceptor side, the developing device is properly mounted on the machine. When the development switching is not performed normally because the developing unit is not set to the normal state, the developing unit is prevented from falling into a locked state, and the developing unit can be easily reset correctly. It is an object to provide a switching device.

(Structure of the Invention) The present invention provides a switching unit for switching a developing unit relative to a photoreceptor between a non-developable position and a developable position, a driving unit for driving the switching unit, and the developing unit. A first detecting means for detecting that the developing device is at the developing-possible position, a second detecting means for detecting that the developing device is at the developing-possible position, a timer for measuring an operation time of the driving means,
When switching the developing device from the non-developable position to the developable position, if the detection signal is not output from the second detection device when the driving device has operated for a predetermined time or more, the first detection device may be used. Determining means for determining whether or not the detection device outputs a detection signal, and when the determination means determines that the first detection means does not output the detection signal, returns the developing device to the non-developable position. Control means for driving the driving means in the reverse direction so as to stop the operation of the driving means when it is determined that the first detection means is outputting a detection signal.

With this configuration, when the developing device is not set correctly on the machine body, when the switching operation is performed, if the switching is not completed even after the elapse of a predetermined time, the state returns to the state before the switching operation. Is prevented beforehand.

(Example) Hereinafter, an example will be described with reference to the drawings.

FIG. 1 shows the overall configuration of an electrostatic copying machine. A body 1 comprises an upper case 3 and a lower case 4 which are provided to be openable and closable by a support shaft 2 at one end. An original mounting table 5 has an exposure device 6 provided therein, and an image forming process unit 7 is supported between the upper case 3 and the lower case 4.

The unit 7 includes a photoreceptor 8 and a main charging device 9, an exposing unit 10, a blank lamp 11, and developers having different colors for multi-color development, respectively, in the peripheral direction of the photoreceptor 8 in the rotation direction. A second developing device that is housed and selectively used for switching
A cleaning device 14 including a developing device including a developing device 12 and a first developing device 13 is provided. The unit 7 is supported at one end by the shaft 15 on the upper case 3 and at the other end by the shaft 16 on the lower case 4.

The lower case 4 is provided at one side thereof with a manual feed tray 17 for transfer paper, paper feed cassettes 18 and 19, and further has a transport path 20 through which the transfer paper supplied from these is transported, and a photosensitive member 8.
Transfer device 21 and separation device 22 located downstream of the developing device 13 in the rotation direction of the photoconductor 8 at the outer peripheral edge of the developing device 13;
A fixing device 23 is provided downstream of the transfer devices 21 and 22 in the transfer direction of the transfer sheet, and is further positioned downstream of the fix device 23 in the transfer direction of the transfer sheet to reverse the transfer sheet during duplex copying. An introduction path 24 and a return path 25 for returning transfer paper during multicolor development (copying) and double-sided copying are provided, and a discharge tray 26 is provided on the other side of the lower case 4.

FIG. 2 shows the part of the unit 7, which is configured so that the second and first developing units 12, 13 can be pulled upward from the unit 7 with the upper case 3 opened as shown in the figure.
As a result, it is possible to further change to a different developing device having a different color. In addition, these developing devices
Although details will be described later, switching means 31 and 3 which are provided so as to be movable with respect to the photoreceptor 8 and are selectively movable between a developing state and a non-developable state.
It has two. The developing devices 12 and 13 are provided with guide plates 35 and 36 which are reciprocally movable substantially linearly with respect to the unit side plates (front and rear) 33 and 34 (FIG. 6) in the above-mentioned distance movement direction.
(The front guide plate is not shown) is set at a predetermined position.

In the drawing, 37 is a pin erected on the unit side plate 34,
Reference numeral 38 denotes a long hole formed in the guide plates 35 and 36. The guide plates 35 and 36 are movably provided by inserting pins 37 into the long holes 38. 39 is the unit side plate 33,3
4 is a holding member which is fixed to the photosensitive member 8 and supports the support shaft so as to sandwich the photosensitive member 8 from both ends.
Positioning stoppers 39a and 39b are provided for the positioning of the developing devices 12 and 13 when the developing device 12 or 13 approaches the photosensitive member 8 and becomes ready for development. By the rollers 45 and 47 abutting against the stoppers 39a and 39b, the distance between the photosensitive member 8 and the developing sleeve 40 described later can be regulated to a predetermined distance. These structures are also shown in FIG. 7 described later.

FIGS. 3 (a) and 3 (b) show the positional relationship with respect to the respective photoconductors 8 when the second and first developing devices 12 and 13 are switched between a developable state and a non-developable state. FIG. 4B shows that the second developing device 12 is in a developable state, and FIG.
Are in a developable state, and one of the states is selected. Further, cases 12a, 13a of the respective developing units 12, 13 are provided.
A cylindrical developing sleeve 40 made of a non-magnetic material is provided inside the developing sleeve 40 so as to face the photoreceptor 8 through a case opening. A magnet (not shown) is provided to perform the operation. Further, a hopper 41 for replenishing toner is provided above the cases 12a and 13a, and a replenishing roller 42 is provided at a toner replenishing port below the hopper 41, and the cases 12a and A stirring roller 43 is provided in 13a.

In the drawing, reference numeral 44 denotes a toner cartridge mounted in the hopper 41 on the first developing device 13 side; 45 and 46, positioning rollers provided on the case end surface (front and rear) of the second developing device 12; Reference numerals 48 denote positioning rollers similarly provided in the first developing device 13, and one positioning roller 45, 47 is provided on a drive shaft of the developing sleeve 40. The positioning rollers 45 to 48 are fitted into the receiving portions 49, 50, 51, 52 of the guides 35, 36 shown in FIG. 2 or FIG. Are set at predetermined positions of the guide plates 35 and 36.

4 and 5 show a front end and a rear end of the developing units 12 and 13, respectively. A gear type driving mechanism 61 and 62 for driving the developing sleeve 40 and the like from a driving source on the machine body side is provided on the rear end surface. Of the driven-side gear groups are provided. That is, the driving mechanism 61
Is a gear 61a for meshing the driven unit 71 with the driven gear 71 indicated by the phantom line at the time of setting, an intermediate gear 61b meshed with the gear 61a, and the intermediate gear 61b meshing for driving the stirring roller 42. The drive mechanism 62 includes a gear 62a meshed with a driven gear 72 indicated by a virtual line in the same manner as described above.
And gears 62b and 62c meshing therewith, a gear 62d coaxially integral with the gear 62c and having a different diameter, and a gear 62e meshing with the gear 62d. The gear 61a is fixed to the drive shaft of the developing sleeve 40 of the second developing device 12 integrally with the positioning roller 45, and drives the developing sleeve 40.
Reference numeral 62b is fixed to the drive shaft of the developing sleeve 40 of the first developing device 13 integrally with the positioning roller 47, and drives the developing sleeve 40. Further, gears 62c, 62d and 62e control the stirring roller 43, respectively. It is driven.

FIG. 6 shows a drive-side gear group of a gear-type drive mechanism provided on the side plate 34 of the unit 7 (body side) and the guide plates 35 and 36 movably supported by the side plate. That is, the guide plate
The driven gears 71 and 72 are respectively supported on the reference numerals 35 and 36, and the driving gears whose gear shafts are supported on the side plates 34 of the unit 7 at positions where they can mesh with the gears 71 and 72. 73,7
4 are provided. The gear shafts of the drive gears 73 and 74 are configured to transmit rotational force from gears 76 and 77 on the drive source side via an electromagnetic spring clutch 75. Then, from the toothed pulley 78 connected to the drive shaft of the motor or the like, the toothed belt
One of the gears 76 is directly meshed with the gear 80 to which the rotational force is transmitted via 79, and the other gear 77 is meshed with the intermediate gear 81.
The torque is transmitted from the drive source to 3,74. The pulley 78 is supported by the shaft 16.

Next, the switching means 31 and 32 will be described with reference to FIGS. 6 and 7 (a) and (b). The switching means 31 includes an elastic leaf spring 31a attached to the back surface of the guide plate 35 and the guide plate 35. A predetermined space is formed by an arm portion 31b protruding to the rear side, and a cam plate 31c that is rotatably supported by a side plate 34 facing this space is provided, and the switching means 32 is provided on a guide plate 36. A predetermined space is formed by the elastic plate spring 32a and the rigid plate 32b similarly attached, and the cam plate 32c is similarly formed in this space.
Is provided. And these cam plates 31c, 32c
A gear integrally provided with the cam plate 32c meshes with an intermediate gear 81 supported by the side plate 34. Further, the output of a development switching motor (drive source) 83 is transmitted to gears 84 and 85 on a support shaft 82 of one cam plate 32c. Are connected via

Further, a cam 87 is attached to the support shaft 82, the cam 87 being in contact with an actuator of a switch detection switch (detection means) 86 for controlling on / off of the motor 83.
The cam plates 31c, 32c are stopped at predetermined positions, and the guide plates 35,
Thus, the developing devices 12 and 13 are reciprocally switched between a developable state and a non-developable state.

FIG. 7A shows a state in which the second developing device 12 can be developed, and FIG. 7B shows a state in which the first developing device 13 can be developed.
When the developing devices 12 and 13 can be developed by rotating the cam plates 31c and 32c, the switching means 31 and 32 are used until the positioning rollers 45 and 47 come into contact with the stoppers 39a and 39b. Then, the guide plates 35 and 36 and the developing devices 12 and 13 are moved.

FIG. 8 shows a block configuration for controlling the development switching motor 83 and the switching detection switch 86. In FIG. 1, reference numeral 101 denotes a CPU (part of control means) for controlling the entire copying machine; 102, an operation unit as input means for the CPU 101; 103, a display unit; 104, an I / O port; Is input to the CPU 101 via the I / O port 104,
The output of the CPU 101 is provided to a forward / reverse rotation drive circuit (a part of the control means) 105 of the motor 83 via the I / O port 104.

The normal development switching operation is performed by driving the motor 83 in the forward direction (one direction). If the switching operation is performed normally, the switch 86 is rotated by the rotation of the cam 87 (FIG. 6). An ON / OFF signal is obtained within a predetermined time, and the operation may be terminated with this. However, developing units 12,1
The positioning rollers 45 to 48 of the 3 are receiving parts 45 to of the guide plates 35 and 36.
If it is not set correctly with respect to 52, a part of the developing devices 12 and 13 will collide with the holding member 39 (FIG. 6) during the switching operation, and the cam plates 3 and 32 of the switching means 31 and 32 will be generated.
1c and 32c are locked, and the switching operation is not completed, so that the ON / OFF signal of the switch 86 cannot be obtained within a predetermined time after the start of switching.

In such an abnormal situation, even if the forward rotation of the motor 83 is stopped, the developing units 12 and 13 are locked, and it is difficult to remove the developing units 12 and 13 from the machine, and the resetting is performed. And the copier cannot be used. Accordingly, in the present invention, in such a case, the motor 83 is reversed to return to the state before the switching operation, and further, a switching abnormality and a reset instruction of the developing device are displayed on the display unit 103. I have. Further, when the developing device has not moved from the position before the switching even though the switching operation was started in the abnormal situation, the motor 83 is turned off.
To display a switching abnormality.

FIG. 9 is a flowchart showing the procedure of the above control. To describe the control procedure by the figure, after performing the select the first or second developing device by the operation unit 102 (color), copy size, the predetermined set number of sheets or the like, ON the print key result (Step S ₁ ), determine whether the developing unit has been selection in developable state at that time (step S _2). Normally, the first developing device 13 is automatically switched to a developable state when a predetermined time has elapsed since the last use of the copying machine. Therefore, in such a case, the first developing device 13 is selected. that when not required for switching the developing unit, because as it is, whereas the process proceeds to the copy process (step S _8), when the second developing device 12 is selected, for switching the developing unit .

Here, if now is the use of the second developing device 12, the ON the developing switching motor 83, is rotated forward (Step S _3), the timer is started in the CPU 101 (step
S _4), see whether developing switching has been completed is set in the timer is within a predetermined time (until the overflow) (step S _5, S _10). The switch 86 is turned off when the development switching is completed.
It can be detected by switching from to ON. When the development switching is completed within a predetermined time, the timer is reset (step
S _6), the motor 83 is OFF (step S _7), it enters the copying process (Step S _8).

When the timer overflows, it is determined that the switching operation is not performed normally because the setting of the second developing device 12 is not normal and the locked state has occurred, and the developing device is moved from the position before the switching. Check whether they are
_11), when I moved, allowed to reverse the motor 83 (step S _12). As a result, the locked state is released, and when returning to the position before switching, the motor is turned off (step S
_13, S _14). Furthermore, to display a switching abnormality, and re-setting instruction to the display unit 103 (step S _15). Also, when not moved from the position before switching in the step S ₁₁ is turned OFF motor 83 performs switching換異normal display (step
S _16, S _17). The determination of the step S _11, the motor 83
The detection can be performed by a detection signal from a rotation detection pulse plate (not shown) or the like provided in the above.

After the copy process (step S _8), and see if the copy completion (Step S _9), the step S _1, if the end
Return to

The user only needs to reset the second developing device 12 in view of the display of the switching abnormality and the reset instruction, and if only the switching abnormality is displayed, there is no abnormality in the motor 83 or its control circuit. You only have to check if it is. Therefore, it is possible to prevent the copier from becoming unusable or calling a service person to request repairs due to only the defective setting of the developing device.

In the above embodiment, the guide plates 35 and 36 are
13 is used as an intermediate member for setting the developing unit. For example, the developing unit is directly supported reciprocally with respect to the side plate 34 of the unit 7 (or the body) and provided on the guide plates 35 and 36. Driven gears 71, 72 etc.
If provided on the side, a configuration in which the guide plates 35 and 36 are omitted can also be adopted.

Further, in the above embodiment, the type in which the developing units 12 and 13 move linearly is shown. However, one end of the case of the developing unit is rotatably supported by the machine body and swings when moving to and from the photosensitive member. The present invention can be similarly applied to a moving type, and can also be similarly applied to a device having one or three or more developing devices.

(Effects of the Invention) As described above, according to the present invention, when the developing device is switched from the non-developable position to the developable position, the detection signal is output from the second detection device when the driving device operates for a predetermined time or more. Is not output, it is determined whether or not the first detection means is outputting the detection signal. If the first detection means is not outputting the detection signal, the developing device is moved to the development impossible position. Drive the driving means in the opposite direction to return,
When the first detection means determines that the detection signal is being output, the operation of the driving means is controlled so as to be stopped. Therefore, it is possible to prevent a locked state due to a defective setting of the developing device, etc. Since the state cannot be released, the image forming apparatus does not become unusable. Therefore, there is no need to call a serviceman, and the user can easily reset the developing device correctly and make the image forming apparatus work again.

[Brief description of the drawings]

FIG. 1 is a front sectional view of an image forming machine in which a developing switching device of a developing device according to the present invention is implemented, FIG. 2 is an enlarged view of a main part of FIG. 1, and FIGS. FIG. 4 is an explanatory view showing a case where the image forming apparatus is selectively switched between a developing possible state and a developing impossible state, FIG. 4 is a front perspective view of the same apparatus, FIG.
7A and 7B are schematic side views showing a switching unit and a driving mechanism in the developing device as viewed in the direction of arrow A in FIG. 6, and FIG. 8 is a perspective view of the switching device. FIG. 9 is a block diagram of the control unit, and FIG. 9 is a flowchart showing the procedure of the control. 1 ... machine, 8 ... photoreceptor, 12, 13 ... developing unit, 31, 32 ...
... Switching means, 83 ... Development switching motor (drive source), 86 ...
... Switch detection switch (detection means), 101 CPU (control means), 105 forward / reverse drive circuit (part of control means).

Continuation of the front page (56) References JP-A-61-151566 (JP, A) JP-A-62-115469 (JP, A) JP-A-61-151576 (JP, A)

Claims (1)

(57) [Claims] A switching means for switching a developing device relative to a photoreceptor between a non-developable position and a developable position; a driving device for driving the switching device; First detecting means for detecting that the developing device is located at the developing position, second detecting means for detecting that the developing device is at the developable position, and a timer for measuring the operation time of the driving means,
When switching the developing device from the non-developable position to the developable position, if the detection signal is not output from the second detection device when the driving device has operated for a predetermined time or more, the first detection device may be used. Determining means for determining whether or not the detection device outputs a detection signal, and when the determination means determines that the first detection means does not output the detection signal, returns the developing device to the non-developable position. Control means for driving the drive means in the reverse direction so as to stop the operation of the drive means when the first detection means determines that the detection signal is being output. Development switching device.