JPS61201272A - Image forming device - Google Patents

Abstract

PURPOSE:To simplify the mechanism and to improve the reliability of a device by coupling two developing devices by the link mechanism, holding one developing device at a development position by an energizing means at any time, and providing the other developing device with a selective energizing means which moves it to the development position. CONSTITUTION:The energizing member 20 is engaged between a pin 29 for main body fixation and a swing member 23 so as to hold a developing device 4 at the development position at any time. The selective energizing means 31 (solenoid) which operates to hold the developing device 4 at a non- development position is fixed to a main body and coupled with the swing member 23 by the link 32. The developing device 4 is selected preferentially for normal copying operation and when a developing device 5 is selected, the solenoid 31 is turned on to separate the developing device 4 from a photosensitive body 1 to the non-development position and also moves the developing device 5 from the non-development position to the development position. Consequently, only one pressing mechanism and one drive source are required, so the mechanism is simplified, the device is reduced in size, and the assembling operation is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Scope of Industrial Application] The present invention relates to an image forming apparatus in which two developing devices are arranged around an image carrier. Part 9 Application: A latent image is formed using an electrophotographic copying machine, recording device, etc., and this! If the image is to be imaged on a 4-wheeled scale, then 9 can be applied.

[Prior art] - In an electrophotographic copying apparatus as shown in FIG.
19 surface is uniformly charged, and an optical image of the document is formed by an illumination and optical system (not shown) through exposure slit 3. The photoreceptor drum is irradiated with light, and an FcL electrostatic image is formed on the front surface of the photoreceptor drum.

Then, use the developer at 4°5 to achieve the above-mentioned effect! Develop the latent image. or,
The transfer material 6 fed by a paper feeder (not shown) is timed and conveyed by a register roller 7, and the toner image on the surface of the photoreceptor drum 1 is transferred by a transfer discharger 8K', and then transferred to the photoreceptor drum. It is further separated and sent to a fixing device (not shown). The surface of the photosensitive drum is cleaned by a cleaning device 9.

[Problem that the invention seeks to solve]

In such an apparatus, for example, in the case of a developer using a two-component magnetic brush development method, the electrostatic image on the photoreceptor is developed by the selected developer, while the other unselected developer develops the electrostatic image on the photoreceptor. There is a problem that the image is disturbed by being rubbed by the developing device.

For this reason, it is necessary to move the developing device away from the photoreceptor to such an extent that it will not be disturbed by the magnetic brush tip of the developing device that is not in use.

In addition, in the apparatus shown in FIG. 2, if the developing device 3 is a developing device using a one-component magnetic toner and the lower developing device 4 is a developing device using a two-component non-magnetic toner, the developing device 3 from the upper developing device 3 is a developing device using a two-component non-magnetic toner. Since the toner scatters downward, it is collected by the developing device 4, causing color mixing.

In order to prevent such image rubbing and color mixing, it is conceivable to configure the developing device that is not used for development to be retracted from the photoreceptor and placed in a position where it is not used for development, as previously described.

For example, as shown in FIG. 3, the solid line indicates the undeveloped position, and the one-dot chain line indicates the developed position.

In the case of such a conventional device, each of the two developing devices has a pressure mechanism, and the pressure means or drive sources for putting each developing device into a developing state and a non-developing state are independently operated by two pressure mechanisms. It was necessary to have For example, as shown in FIG.
The pressure levers 1 and 13 are arranged to rotate around rotational shafts 10 and 12, respectively.

On the other hand, the developing devices 4 and 5 have rotation centers 14 and 15, respectively, and are always located away from the photoreceptor 1 (non-developing state) due to their own weight.

Because of this configuration, as described above, the developing units 4 and 5
However, when choosing one of these, a pressure means and a driving source are required for each developing device, which causes problems such as the device being large and complicated and the ease of assembly being reduced.

[Means for solving problems]

In order to eliminate the drawbacks of the above-mentioned conventional example, the present invention simplifies the mechanism by engaging two developing surfaces with a link mechanism, and furthermore, one developer is always held at the developing position by a biasing means, and the other is By providing a selective biasing means for moving one of the developing devices to the developing position, it has become possible to simplify the mechanism and improve the reliability of the device.

〔Example〕

The present invention will be explained below using examples.

In FIG. 1, two developing devices 4.5 are arranged around the photoreceptor 1, as in FIG. The developing units 4 and 5 include
There are handles 16 and 17 for inserting and removing the stones toward the front, and they also rest on the developing device support members 18 and 19, respectively, and engage with the convex grooves, and move toward the front along the grooves. It can be inserted and removed. Each developing device support member 18, 19 is a guide member 20a fixed to the main body.

21a respectively. The developing device 4.5 is also guided by guide members 20b and 21b fixed to the main body, respectively. The developing device 4.5 can be moved left and right by the guide members 20a, 20b and 21ji, 21b. Also, S + in the figure.

Ss is a non-magnetic sleeve having an internal magnetic roller, and toner is conveyed by this sleeve to develop the latent image on the photoreceptor 1.

On the other hand, a swinging member 23 is provided which can swing around a pin 22 fixed to the main body. In the development stage 18, 19, bins 24, 25 are provided, which are engaged with elongated holes 26, 27 of the swinging member 23. Further, in order to keep the developing device 4 at the developing position at all times, a biasing member 28 is engaged between a bottle 29 fixed to the main body and a pin 30 on the swinging member 23, as shown. Also, a selective biasing means 31 (solenoid) that acts in a direction to keep the developing device 4 in a non-developing position.
is fixed to the main body and engaged with the swinging member 23 by a link 32.

The state shown in FIG. 2 shows the state in which the solenoid 31 is OFF and the developing device 4 is set.

Therefore, in normal copying operations, developer 4 is selected preferentially, and when developer 5 is selected (for example, when a signal from the developer switch button on the operation panel is detected) ), the solenoid 31 is turned on, and the developing device 4 is pulled away from the photoconductor 1 to the non-developing position as shown in 4.
, set the container 5 from the non-developing position to the developing position. However, one member 33 of the swinging member 23 serves as a member to prevent the developing device 4 from being removed, which normally prevents the developing device 4 on the priority side from being inserted or removed. This means changing the developing device (especially to develop a different color) while the developing device is close to the photoreceptor (development position state),
This is to prevent damage to the photoreceptor when pulling it out (mainly during maintenance).

In addition, a manual positioning member 35 that can be rotated around a bin 34 fixed to the main body is attached as shown in the figure, and by holding the handle 36 and rotating it in the direction of the arrow shown in the figure, the tip cam of the manual positioning member 35 can be moved. It enters the recessed portion 37 that engages with the above-mentioned cam provided on the swinging member 23, and sets the two developing devices 4.5 at the neutral position i with a distance from the photoreceptor 1.

FIG. 4 shows this state.

When set as shown in Fig. 4, the priority side developer 4
The safety mechanism for preventing insertion and removal is also released, and the member 33 prevents the developing unit 4 from being inserted and removed.
, and the developing device 5 is set at almost the same position as the developing device 5, so that both the developing devices can be inserted and removed, that is, replaced. [Other Embodiments] In this embodiment, the developing device 4 is preferentially selected, but it does not matter which of the two developing devices is in the priority mode. In addition, in this embodiment, a solenoid was used as the selective biasing means, but other driving means may be biased by a motor and an eccentric cam, or the drive can be obtained from a drive system within the machine body to make one rotation. The bias may be applied by driving the eccentric cam with a taratch or the like. ,,
Furthermore, the image carrier is not limited to a photoreceptor, but may also be an insulator.

Also good. Of course, the other side of the developing device is the conventional one' component□
, L,: The component system is long. , ,・
” , Su [Effect of the invention] ”” ””””
' ”” ”' □.

As explained above, two units are linked, eight units are linked, and eight units are linked.
, the biasing means (chi, = >, ,,,,
, : Me, Developing: Keep the device 1' at the developing position at all times,
1. Move the other S member, container,,,' to the developing position, and perform the optional step-j'.

By providing this, the pressurizing mechanism and drive source are eliminated. 4. Simplification of the mechanism and miniaturization of the device 1. Assembly and explosion 4. improvement effect
,・□Also, since one of the two developing devices is always in the developing position and the other is always in the non-developing position, both developing devices will not be set in the developing position at the same time due to malfunction of electricity etc. On the other hand, since both developing devices are not set in the non-developing position, at least the priority developing device alone can perform development and can perform the minimum function.

Also, both developing devices can be put into a non-developing state by manual operation.
When replacing the developing device and the photoreceptor, the work can be done safely and easily without damaging the photoreceptor.

[Brief explanation of drawings]

°Figure 1 is a sectional view of a conventional device. FIG. 2 is a sectional view showing the developing device in a conventional device. FIG. 3 shows an embodiment of the present invention,
Cross-sectional view. Figure 4 shows a diagram related to another implementation of the present invention! ′ side view. `` In the introduction, 4.! is the developer, 18.19 is the developer:
Tsuni: 2 = ゛ ni ni; ゛: ° cho 2; 2::: indicates two.・Applicant: Canon Co., Ltd.

Claims (3)

[Claims] (1) It has first and second developing means around the image carrier, and two engaging parts, first and second, sandwiching the center of swing, and the first
and a swinging member capable of assuming a second position, the swinging member engages with the first developing means through the first engaging portion, and engages with the second developing means through the second engaging portion. and when the rocking means is in the first position, the first developing means is moved to the developing position, the second developing means is moved to the non-developing position, and the rocking means is in the second position. An image forming apparatus characterized by moving the first developing means to a non-developing position and moving the second developing means to a developing position when the image forming apparatus is in the developing position. (2) A biasing device that acts to move the swinging device to a predetermined position, and a selective biasing device that selectively moves the swinging device from the first position to the second position. An image forming apparatus according to claim (1), characterized in that it has: (3) The swinging member is placed between the first position and the second position, and the first and second developing means are moved to the third position. The image forming apparatus according to claim 1, further comprising a manual positioning member.