JPS63138367A - Developing device - Google Patents

Abstract

PURPOSE:To rotate a development part efficiently with a small rotary driving force by providing eccentric cams which are driven to rotate and engage either of a development part and a rotary interlocking body. CONSTITUTION:A driving mechanism is provided with plural 1st eccentric cams 25 which abut on the opposite surface part of the developing case 12 of a 1st developing part 41 from a photosensitive body 1 and rotate the developing case 12 to leave the photosensitive body 1 and the eccentric cams 25 are fitted integrally to a rotary shaft 26 provided in parallel to the support shaft 13 of the developing case 12. Further, a 2nd eccentric cam 27 is fitted in one body closely to an end part of the rotary shaft 26 and eccentric with the 1st eccentric cams 25 by a prescribed angle. For the purpose, both eccentric cams 25 and 27 are rotated by the prescribed angle at each time to switch both development parts 41 and 42 from a 1st attitude to a 2nd attitude and from the 2nd to the 1st attitude alternately.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a developing device installed in an image forming apparatus such as an electrostatic copying machine or a facsimile machine, and more specifically, the present invention relates to a developing device installed in an image forming apparatus such as an electrostatic copying machine or a facsimile machine. A plurality of developing sections containing developers of different colors are provided around the photoreceptor, and the developing sections are selectively operated to transfer the electrostatic latent image formed on the surface of the photoreceptor to the selected developing section. The present invention relates to a developing device that visualizes corresponding colors.

<Prior Art> As a developing device capable of selecting the above-mentioned developing form, for example, as disclosed in Japanese Patent Application Laid-Open No. 80-138575, a first developing section and a second developing section each containing developers of different colors are used. A developing sleeve made of a non-magnetic material is rotatably provided in each of the plurality of developing parts, and a magnetic roller is rotatable at a predetermined angle. It is known that these are arranged inside each of the developing sleeves.

The above-mentioned developing device rotates and deviates the magnetic rollers of both developing sections by a predetermined angle, thereby forming spikes of developer on the surface of the developing sleeve facing the photoreceptor in one developing section. The one developing section can be placed in a developing state.

Further, in the other developing section, by removing the developer from the surface of the developing sleeve facing the photoreceptor, the other developing section can be placed in a non-developing state. The first developing section and the second developing section are connected separately to transmission systems branched and connected from a common drive source, and a one-way clutch is interposed in each transmission system, so that the drive source By selecting the forward or reverse direction of rotation, the developing section on the side that is not involved in the development is placed in a state where the drive is stopped.

<Problems to be Solved by the Invention> According to the developing device configured as described above, a drive system with a complicated structure for individually and selectively rotating the sleeves provided in each developing section and a magnet rotating are required. Since a drive system is required to move the device, there is a problem that the device is expensive.

In order to solve these problems, the applicant of the present application has developed a developing device that first makes one of the developing sections ready for development by moving the developing section itself closer to or away from the photoreceptor. (See Japanese Patent Application No. 80-152037).

According to the developing device with the above configuration, the structure can be greatly simplified, but the developing section is moved by a cam that is reciprocated by a solenoid. Since the motion is converted into rotational motion, the mechanical efficiency is low, and as is clear from the provision of two solenoids, a large drive force is required to ensure the desired drive torque from the cam. The problem of doing so remains.

Purpose> This invention was made in view of the above problems, and by moving a plurality of developing sections, any one of the developing sections can be selectively brought into a developing state. It is an object of the present invention to provide a developing device that can efficiently move parts with a small driving force.

Means for Solving the Problems> In order to achieve the above object, the developing device of the present invention includes a plurality of developing sections, each of which is provided rotatably around an axis parallel to the rotational axis of the photoreceptor. In addition, when any one of the developing sections is rotated to a development possible position close to the photoconductor, a rotation interlocking body that maintains the other development section in a development disabled position away from the photoconductor; a driving means for driving the developing section rotated to the position; and an eccentric cam that is rotationally driven by a rotational drive source and engages with at least one of the developing section and the rotation interlocking body to rotate them. It is set up.

According to the developing device configured as described above, the eccentric cam rotationally driven by the rotational drive source brings any one of the plurality of developing sections close to the photoreceptor, and the brought close developing section is brought close to the photoreceptor. , it is possible to bring the developing section into a developable state, and the developing section in the developable state can be driven by the driving means. Moreover, due to the rotational interlocking body, when any one of the developing sections is in a developing state, the other developing sections can be maintained in a non-developing state. Furthermore, since the eccentric cam is rotationally driven by the rotational drive source, the driving force of the rotational drive source can be efficiently transmitted to the eccentric cam.

<Example> Embodiments will be described in detail below with reference to the accompanying drawings showing embodiments.

FIG. 1 is a schematic diagram showing the copying processing section of an electrostatic copying machine, in which a photoreceptor (1) is surrounded by a charger [2], an exposure device (3), a developing device (4), a transfer charger ( 5),
A separation charger (6) and a cleaning device port are arranged in this order toward the rotation direction R of the photoreceptor (1).

The developing device (4) has a first developing section (41) and a second developing section (42) that have the same basic configuration, and also has a first developing section (41) and a second developing section (42). To drive the posture switching means (8) which makes one of them in a developable state and the other one in a non-developable state, and the first developing section (41) or the second developing section (42) which are in a developable state. gear drive means (10) (see Figure 9)
They each have

A part of a hopper (11) for replenishing toner is provided in a predetermined part of the developing case (12) of each of the first developing section (41) and the second developing section (42), and the developing case The photoreceptor [1
] A support shaft (13) is provided that is parallel to the rotation axis of the rotary shaft.

-The supporting shaft (13) is supported by a pair of holding plates (14) fixed to the main body of the copying machine, so that the developing case (12) is held at a predetermined angle about the supporting shaft (13). It is hung so that it can rotate freely.

The holding plate (14) is fixed to a predetermined part of the main body of the copying machine while sandwiching the photoreceptor (1), and as shown in detail in FIG. ) is the annular first bearing that supports the support shaft (1a) of the part (14a).
, and a semicircular second bearing that supports the support shaft (13) of each developing case (12) is formed as a portion (14b), and a third bearing as a portion (14c). Further, a predetermined portion on the opposing surface side of each holding plate (14) is in contact with a sleeve shaft (34) (see FIG. 2) of a first developing section (41), which will be described later. ) toward the photoreceptor (1) at a predetermined angle.
4d) and a second stopper that comes into contact with the sleeve shaft (35) of the second developing section (42) and restricts the rotation of the second developing section (42) toward the photoreceptor (1) at a predetermined angle. (14e)
and is provided. Each of the above bearings has a section (14a
) (14b) (14c) The mutual center-to-center dimensions are set to a predetermined tolerance in order to accurately arrange the photoreceptor (1) and each developing section (41) (42) at a predetermined position, The first bearing is located between the center of the portion (14a) and each stopper (
14d) (14e), and the distance between each developing section (41) (4
2) is set to a predetermined tolerance in order to accurately regulate the rotation toward the photoreceptor (1) at an appropriate position. In this way, by integrally arranging the photoreceptor (1) and the developing sections (41, 42) with their mutual spacing regulated by the pair of holding plates (14), they can be easily attached to the main body of the copying machine. Assembling can improve accuracy compared to when assembling the parts individually. Moreover, since there is no need to adjust the position of each member during the assembly, assembly can be facilitated. Furthermore, each of the above stoppers (14d) (1
Each stopper surface (S) of 4e) is formed into an arcuate surface concentric with the first bearing part (14a), and the bearing parts (14b) and (14c) are worn out, causing the sleeve shaft (3
4) and the first stopper (14d), and the position of contact between the sleeve shaft (35) and the second stopper (14e) are shifted downward, respectively.
The gap between the developing sleeve (16), which will be described later, does not change.

Furthermore, a developing sleeve (16) made of a non-magnetic material is provided inside each developing case (12) so as to face the photoreceptor (1) through the case opening (15). A magnet (17) for forming spikes of developer on the sleeve surface facing the photoreceptor (1) is provided inside (1B). In addition, some of the above hoppers (
11) A toner replenishment roller (19) is provided at the lower toner replenishment port (18), and a stirring roller (20) is provided below the toner replenishment roller (19). . In addition, each developing section (41) (42) is
The center of rotation, that is, the location of the support shaft (13), so that the developing sleeve (16) comes close to the photoreceptor (1) by rotation due to its own weight, that is, becomes ready for development. is set.

In the following, for convenience, the first developing section (41
) is in a non-developing state where it is separated from the photoconductor (1), and the second developing section (42) is in a developing state where it is close to the photoconductor (1) is called the first posture; 42) is in a non-developing state away from the photoreceptor (1), and the first developing section (41) is in a developable state close to the photoreceptor (1), which is referred to as a second attitude.

As shown in FIGS. 2 and 3, the attitude switching means [8] is configured to move the second developing section (42) from a developing position close to the photoreceptor (1) to from a developing position close to the photoreceptor [1]. A rotation interlocking body (22) that rotates the developing case to a non-developing position is provided along both sides of each developing case (12). The tip (22a) of the rotation interlocking body (22) engages with the lower surface of the engagement pin (24) protruding from both ends of the developing case (12) of the second developing section (42). The middle part (22b) is a locking pin (22b) fixed to the main body of the copying machine.
3) is engaged with the upper surface. Further, the base end (22c) of the rotation interlocking body (22) is provided with a drive mechanism 1, which will be described later.
The second eccentric cam (27) of 9) is rotatably fitted.

Further, the attitude switching means (8) includes a first developing section (
41) and a drive mechanism (9) for switching the postures of the second developing section (42). To explain in more detail with reference to FIG. 8, the drive mechanism (9) has a mechanism that comes into contact with the surface of the developing case (12) of the first developing section (41) on the side opposite to the photoreceptor (1). A plurality of first
An eccentric cam (25) is provided, and this first eccentric cam (25) is integrally attached to a rotating shaft (26) provided parallel to the supporting shaft (13) of the developing case (12). It is being Also, near the end of the rotating shaft (2B),
The second eccentric cam (27) is integrally attached to the first eccentric cam (25).
It is eccentrically shifted by a predetermined angle from the center.

That is, as shown in FIG. 4, the second eccentric cam (27) is rotated by the rotation interlocking member when the developing case (12) of the first developing section (41) and the first eccentric cam (25) are farthest apart. (
22) can be rotated clockwise around the pin (23) by the maximum angle, and the first eccentric cam (25) is turned half a turn from the state shown in FIG. 4, as shown in FIG. 5. The rotation interlocking body (22) is eccentrically positioned so as to be able to rotate counterclockwise through the maximum angle around the pin (23). Furthermore, a cam plate (28) that rotates concentrically with the rotating shaft (26) is provided at a predetermined portion of the rotating shaft (28), and the cam plate (28) ) A microswitch (29) is arranged. The above microswitch (
29) is turned OFF when the developing case (12) of the first developing section (41) and the first eccentric cam (25) are separated from each other the most as shown in FIG. The operation is controlled by the cam plate (28) so that the cam (25) is turned ON when it has rotated half a turn from the state shown in FIG. 6.

The rotating shaft (26) is rotated at predetermined timings in the direction of arrow X in FIG. 8 by a motor (not shown) serving as a rotational drive source. The drive of the motor is controlled by inputting a signal from a microswitch (29) so as to rotate the rotating shaft (26) in half-turn increments.

If the drive mechanism (9) has the above configuration, the first eccentric cam (
25), the first developing section (41) can be rotated, and the second eccentric cam (27) can rotate the second developing section (41) via the rotation interlocking body (22).
2) can be rotated, both eccentric cams (25
) (27) by a predetermined angle, both developing sections (41) and (42) in the first posture are changed to the second posture (
(See FIGS. 2 and 4), the developing sections (41, 42) in the second attitude can be alternately switched to the first attitude (see FIGS. 3 and 5). To elaborate further,
From the second attitude shown in Fig. 4, both eccentric cams (25) (2
7) by half a rotation, the developing case (12) of the first developing section (41) and the first eccentric cam (25) are brought into contact with each other, and the first developing section (41) is subjected to the biasing force due to its own weight. It can be turned away from the photoconductor (1) by rotating against the
At the same time, the second eccentric cam (27) rotates the rotation interlocking body (2).
Rotate 2) counterclockwise around the pin (23),
The second developing section (42) can be rotated by the biasing force of its own weight and brought close to the photoreceptor (1). At this time, the sleeve shaft (35) of the second developing section (42) is brought into contact with the second stopper (14e) of the holding plate (14), so that the second developing section (42) can perform proper development. It can be stopped at any position. Furthermore, by rotating both the eccentric cams (25) and (27) by half a rotation from the first attitude shown in FIG.
The first developing section (41) is separated from the eccentric cam (25).
The second eccentric cam (2
7), the rotation interlocking body (22) is rotated clockwise around the pin (23), the second developing section (42) is rotated against the biasing force due to its own weight, and the photoreceptor] 1). At this time, the first developing section (41) is connected to the first stopper (14d) of the holding plate (14).
The first developing section (41) is brought into contact with the sleeve shaft (34) of the
) can be stopped at an appropriate developing position. In addition, when changing the posture described above, the second developing section (42)
The second eccentric cam (
Since the rotation interlocking body (22) is forcibly rotated in step 27), the separating operation of the second developing section (42) can be performed stably. Moreover, since the second developing section (42) is rotatably driven separately from the first developing section (41), the separation operation described above can be performed more reliably.

In addition, the driving torque of the first eccentric cam (25) required for changing the posture only needs to be set so that at least the first developing section (41) can be separated from the photoreceptor (1), so the driving torque is reduced. It is possible to efficiently switch postures using force.

Next, the specific configuration of the gear drive means (10) will be explained with reference to FIG. 9. The above gear drive means (1
0) is provided with a main drive gear (G) and first and second drive gears (Gl) (G2) that are attached to the main body of the copying machine and are in mesh with each other.

Then, when the first developing section <41> is in a developing state, the first driven gear (G3) meshing with the first driving gear (G1) is connected to the sleeve shaft ( 3
4), and a second driven gear (G4) that meshes with the second drive gear (G2) when the second developing section (42) is in a developing state, is provided in the second developing section (42). 42
) is provided on the sleeve shaft (35). Further, in the first developing section (41), the first driven gear (G3)
Meanwhile, the stirring gear (G
6) are interlocked and connected, and the second developing section (42
), a stirring gear (G7) is connected to the second driven gear (G4) via an idle gear (not shown). Further, in the second developing section (42), as shown in FIGS. 2 and 3, a gear (
G8) is provided on the sleeve shaft (35), and a gear (G9) provided on the toner supply roller shaft (40) can be engaged with this gear (G8) via an idle gear (not shown). There is.

With the above configuration, the first developing section (41) and the second developing section (42) are rotated in opposite directions to bring one of the developing sections (41) (or (42)) into a state ready for development. , when the other developing section (42) (or (41)) is switched to the non-developable state, the one developing section (41) (or (42)) that was switched to the developable state is changed to the drivable state. The developing section (42) (or (41)
) can be placed under a deactivated state.

In addition, as shown in FIG. 11, engagement pins (21) are provided protruding from both sides of the first developing section (41).
If the pin (24) of the second developing section (42) is fitted with the rotation interlocking body (22) with a predetermined degree of freedom, the second eccentric cam (27) can be omitted. However, in this case, the rotation biasing force generated by the difference in weight between the first developing section (41) and the second developing section (42) is used to move the first developing section (41) to the photoreceptor (42). 1), and at the same time, the second developing section (42) is moved away from the photoreceptor (1).

In addition, in the embodiment shown in FIG. 1, the first
The pin (21) of the developing section (41) and the pin (24) of the second developing section (42) should be fitted with each other with a predetermined degree of freedom relative to the rotation interlocking body (22). For example, the first eccentric cam (25) can be omitted, and each developing section (41) (42) can be forcibly rotated only by the rotational drive of the rotation interlocking body (22) by the second eccentric cam (27). It becomes possible to do so.

Further, the developing device of the present invention directly transmits the driving force from the rotational drive source to the rotational Idl (2B) (5 to I).
In addition, it is also possible to use the drive system of the copying machine main body as the rotational drive source, and in this case, the motor as the rotational drive source can be omitted.

Although the embodiment shown in FIG. 1 shows the case where two developing units are configured, it is also possible to add more developing units, and in this case, depending on the number of developing units configured,
What is necessary is to add a rotation interlocking body and an eccentric cam for rotating the rotation interlocking body, and various other design changes can be made without changing the gist of the invention.

<Effects of the Invention> As described above, according to the development ci of the present invention, by rotating a plurality of development units, each development unit can be selectively brought into a developing state. In addition to simplifying the structure and reducing costs compared to a configuration in which the magnet rotates, the rotation of the eccentric cam is driven by the rotary drive source, so the driving force of the rotary drive source can be reduced. This has the unique effect of being able to efficiently transmit the rotation to the eccentric cam and, in turn, allowing the developing section to rotate efficiently with a small amount of rotational driving force.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of the copying processing section, FIGS. 2 and 3 are illustrations of the operation of the attitude switching means, FIGS. 4 and 5 are illustrations of the attitude switching of the developing section, and FIGS. 6 and 7. The figure is an explanatory diagram of the operation of the microswitch, Figure 8 is a perspective view of the main parts of the attitude switching means, Figure 9 is a schematic diagram of the gear type drive means, Figure 10 is a front view of the holding plate, and Figure 11 is the other A schematic sectional view showing an example.

Claims (1)

[Claims] 1. Color is displayed around the photoconductor rotating in one direction. Multiple developers containing developers with different colors a developing section, and selectively operating the developing section. the color corresponding to the selected developing area. In the developing device that performs development, Each of the multiple developing sections is Rotatable around an axis parallel to the axis of rotation In addition to providing one of the developing The part is rotated to the developing position close to the photoreceptor. If the other developing section is kept in a non-developable position away from the photoreceptor. Rotate the rotating interlocking body that holds it to the developing position. a driving means for driving the moved developing section; Rotationally driven by a rotational drive source, and the above At least one of the developing section and the rotation interlocking body; an eccentric cam that engages and rotates them; A developing device characterized by being provided with.