JPS58136062A - Rotary developing device - Google Patents

Abstract

PURPOSE:To prevent toner from leaking and scattering by providing a flexible coating member which opens and close the development openings of plural developing devices and a driving mechanism for moving it back. CONSTITUTION:When a developing device 19 is positioned facing a photoreceptor, a winder 19e winds a covering sheet 35 to open a development opening 19b. When a command signal for developing device replacement is supplied externally after development ends, the motor in the winder 19e operates to rotate a winding barrel and the covering sheet 35 is fed out to cover the entire surface of the development opening 19b. A positioning hole faces a plunger where the leading edge of the covering sheet abuts on a stopper 36 and a detecting means detects that to stop the motor. Other development parts 20 and 21 has the same constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary developing device, and particularly to a rotary developing device using powder developer (hereinafter referred to as toner).

For example, a color copying machine separates a document into three colors, red, green, and blue, and develops the light image corresponding to each color separately with cyan, masseinter, and yellow toners, which are complementary colors of each color. Requires multiple containers. In this case, constructing each developing device separately and arranging them in parallel around the image holder increases the size of the apparatus. Therefore, a rotary developing method is used in which a plurality of developing devices containing toner are arranged around a rotation axis and the developing port of each developing device is selectively brought close to the electrostatic latent image holder. A device has been proposed.

Although this rotary developing device is extremely effective for downsizing, it has problems with toner leaking and scattering from a developing port that is not used for development.

If the above-mentioned leaked and scattered toner adheres to optical components, the optical characteristics will be significantly impaired and image quality will deteriorate.
If it adheres to electrical parts, it can cause short circuits and malfunctions. Furthermore, if it adheres to the sliding parts of mechanical parts, it will significantly accelerate wear and reduce the durability of the machine. especially,
In the case of color development, if leaked and scattered toner mixes with toner in a developing device of another color, areas on the copy that are not developed with the proper toner will result in an unsightly image.

Conventionally, in order to prevent toner leakage and scattering, as mentioned above, a duct suction port was provided around the developing device,
A device in which the developing device is surrounded by an elastic sponge has been proposed. However, the former requires larger equipment and is more expensive. Also, the noise is loud. The latter is inexpensive and does not take up much space, but it is difficult to completely seal it, and when used for a long time, it has the disadvantage that leakage of toner and color mixing of scattered toner cannot be ignored.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotary developing device equipped with a toner scattering prevention mechanism that can reliably prevent leakage and scattering of toner in the rotary developing device with a simple configuration.

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 is a cross-sectional view showing an outline of a color copying machine, in which a document placement glass 2 is provided on the top surface of the copying machine main body 1, and a document 3 placed on the glass 2 is moved while being irradiated with a light source 4. An exposure optical system consisting of mirrors 5 and 6, lenses 7, and fixed mirrors 8 and 9 slit-exposes an original image onto a photoreceptor 10 serving as an electrostatic latent image holder. In this case, moving mirror 5
The moving speed of the moving mirror 6 is 1/2 of the moving speed ■.
■It is. A primary charger 11 is provided around the photoreceptor 10,
- Simultaneous secondary charging - A light device 12, a full exposure lamp 13, a rotary developing device 14, transfer the visible image on the photoreceptor 10 to the transfer body 1
A transfer charger 17 that transfers the image to the paper P on the surface of the photoreceptor 6, and a cleaning blade 18 that cleans the surface of the photoreceptor are arranged in this order.

As shown in FIGS. 2 and 3, the rotary developing device 14 has a plurality of developing devices arranged around a rotating shaft 15, namely, a developing device 19 having a yellow developer, a developing device 19 having a magenta developer, and a developing device 19 having a yellow developer; a developing device 20 having a cyan developer; a developing device 2 having a cyan developer;
1 are arranged and fixed with screws 23 to mounting arms 22a to 22C extending in three directions of a mounting plate 22 provided at both ends of the rotating shaft 15. A gear 24 provided at the end of the rotating shaft 15 is meshed with a gear of a rotational force transmission system (not shown). Each of the developing units 19 to 21 has a cylinder 19a to 21a having a fan-shaped cross section, and a developing port 19b to 21b provided in the longitudinal direction of the arcuate surface of each cylinder.

Magnet rollers 19C to 21c are rotatably supported in the container cylinder facing each developing port, and a cleaning blade (
(not shown). The rotating shaft 1 of the magnet rollers 19C to 21C protrudes outside the container barrels 19a to 21a.
Gears 19d to 21d are attached to 90 to 21o,
A gear on a magnet roller shaft of a developing device having a developing port facing the photoreceptor 1° is meshed with a rotational force transmission system gear (not shown).

The photosensitive member 10 and the transfer member 16 have the same diameter.

While rotating at the same speed in opposite directions as indicated by the arrows, the color separation filter 25 provided between the fixed mirrors 8 and 9 is selectively rotated for each slit exposure to produce a color-separated electrostatic latent image of a specific color. is formed on the photoreceptor 10.

Then, when the electrostatic latent image is formed by a blue filter, it is developed with a yellow developer, when it is formed with a green filter, it is developed with a magenta developer, and when it is formed with a red filter, it is developed with a cyan developer. The developed visible images are sequentially transferred onto the transfer paper P wound around the transfer body 16 in a superimposed manner. This transfer paper P is the photoreceptor 10
The paper is fed out from the paper cassette 27 by the paper feed roller 26 in synchronization with the rotation of the paper, travels between a pair of guide plates 28 and 29, and is wound and supported around the transfer body 16 by a holding mechanism (not shown). After the transfer is completed, the transfer paper P is separated from the transfer body 16 by a separation mechanism (not shown), passes through fixing rollers 30 and 31, is heated and pressurized, and is discharged onto a tray 32.

The present invention relates to each developing device 19 to 21 of the rotary developing device 14.
A long covering member (hereinafter referred to as a cover sheet) 35 made of metal foil or synthetic resin that opens and closes the developing ports 19b to 21b, and this covering sheet is rolled up or fed out to open and close the developing ports. The winding machines 192 to 21e are provided for winding. The winder has a mounting plate 4 provided on the end face of each developer so that the horizontal sheet 35 is moved forward and backward along guides 33 and 34 formed at the edges of the opposite opening in the longitudinal direction of the developer opening.
It is attached to 0.42.

The above-mentioned guides 33 and 34 protrude outward from the outer circumferential surface of the developer boxes 198 to 21a, but the enemy of these protrusions is the developing ports 19b to 21b of the magnet rollers 19c to 21c, as shown in FIG. The maximum protrusion amount υ is also low, and the rotary developing device is configured so as not to come into contact with the photoreceptor 10 even when it rotates.

As shown in FIG. 3, the ends of the guides 33 and 34 facing the winding machine are open, and a stopper 36 for the cover sheet 35 is provided at the other end.

As shown in FIG. 4, the winding machine houses a motor 38 inside a winding drum 37 that winds up the cover sheet 35, and fixes a side plate 37a of the winding drum 37 to an output shaft 38a of the motor 38.
- The output shaft 38a passing through the nuclear side plate is connected to the bearing 39
It is supported by the above-mentioned mounting plate 40 via. On the other hand, a hollow shaft 41 provided on the other side of the motor 38 is attached to a mounting plate 42, and this hollow shaft 41 supports the side plate 37b of the winding drum 37 via a bearing 43. Reference numeral 44 designates a cover that covers the outer periphery of the winding drum, and a portion thereof is provided with an outlet 45 for taking out the cover sheet 35, as shown in FIG. As shown in FIG. 2, the cross-sectional shape of this cover sheet is a semicircular arc having a radius larger than that of the outer peripheral surface of the magnet roller. The above mounting plate 42
The tip of a plunger 47 that enters and exits from this solenoid is loosely fitted into a positioning hole 48 formed in the side plate 37b of the winding drum 37 between the solenoid and the winding drum 37. A spring 49 is compressed between the solenoid 46 and the plunger 47.

A lead wire 50 of the motor 38 passes through the inside of the hollow shaft 41 .

The device of the present invention has the above-mentioned configuration, and its operation will be explained below. As shown in FIGS. 1 and 2, when the developing device 19 is in a position facing the photoreceptor 10, the cover sheet 35 is wound up by the winder 19e of the developing device, and the developing device 19 is
b is open. After the development by the developing device 19 is completed, when a command signal for replacing the developing device is given from outside, for example, the motor 38 inside the winder 19e is activated, and its output shaft 38 is activated.
a→The winding drum 37 rotates through the side plate 37a of the winding drum 37, and the cover sheet 35 is fed out to cover the entire surface of the developing port 19b.

A positioning hole 48 faces a plunger 47 at a position where the leading end of the cover sheet hits the stopper 36, and the plunger 47 is pushed out by a spring 48 and engaged with the positioning hole 48. This movement of the plunger or cover sheet 35 is detected by a detection means (not shown), and the power to the motor 38 is turned off. Also,
In connection with the above detection, the drive source of the rotary developing device 14 is activated, and when the next developing device 20 reaches a position facing the photoreceptor 10, this is detected by a detection means (not shown). Stop the drive source. In connection with this stopping operation, the motor 38 of the winder 20e of the developing device 20 is activated, and at the same time the solenoid 46 is energized, and the plunger 47 is moved by the spring 49.
It is suctioned against the force and released from the positioning hole 48. As a result, the winding cylinder 37 rotates to take up the cover sheet 35 and open the developing port 20b.

In addition, the magnet rollers 19c~ of each developing device 19~21
21c and the photoreceptor 10 (2. At both ends of the shaft of this magnet roller, roller holes having a larger diameter than the magnet roller (the difference in radius between the two becomes the distance value) are installed. In the rotary developing device installed as shown by the chain line in FIG. 3, the developing device is rotated and the roller box is moved to a position where it does not come into contact with the photoreceptor, and then the covering silt 35 is opened and closed.In this case, the developing device Since the magnetic roller is disposed at the developing port, even if the developing device moves to a position that does not face the photoconductor and the developing device rotates, toner will not leak or scatter. There is no risk of this happening.

As described above, the present invention arranges a plurality of developing devices on a circumference centered on a rotating shaft, and selectively electrostatically charges the developing ports of each developing device by rotating the rotating shaft. In a powder developing device that performs development while facing a holding body, a flexible breaking member moves back and forth in the axial direction of the rotating shaft to open and close the development port E, and a drive mechanism moves the covering member back and forth. Since these are separately provided in each of the developing units, leakage and scattering of toner from each developing unit can be reliably prevented with a simple configuration. In addition, effects such as the ability to move the covering member back and forth smoothly without requiring a special space can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing an outline of a color copying machine equipped with a rotary developing device, and Fig. 2 is a cross-sectional view showing the toner scattering prevention value of the present invention.
3 is a perspective view thereof, and FIG. 4 is a longitudinal sectional view of a winder for a flexible covering member. 10 is an electrostatic latent image holder; 15 is a rotating shaft of a rotary developing device; 19 to 21 are developing devices; 19b to 21b are developing ports; 35
196 to 21e are flexible covering members, and 196 to 21e are winding machines. (11)

Claims (1)

[Claims] A plurality of developing devices containing powder developer are arranged on a circumference centered on a rotating shaft, and the development port of each developing device is selectively opposed to the electrostatic latent image holder by rotation of the rotating shaft. In the rotary powder developing device, a flexible covering member moves forward and backward in the axial direction of the rotating shaft to open and close the development opening, and a winder moves the covering member fully back and forth, and the flexible covering member moves forward and backward in the axial direction of the rotating shaft to open and close the development opening, and the winding machine moves the covering member fully back and forth. A rotary developing device characterized in that each developing device is provided separately.