JPH0564346B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention prevents the scattering of developer from the developing section of a rotary developing machine used in printers, copying machines, etc., when the device is not in operation. The present invention relates to a developing device designed to prevent such problems.

[Prior art]

As a conventional developing device, for example, there is one shown in FIG. 1, which has a triangular cross-sectional shape, each inner corner is open, and the interior is divided into three in the longitudinal direction, and each section has a developing device 1a, 1
a housing 2 in which each of the components b and 1c are formed, and developing rolls 3a, 3b, which are rotatably installed within the section, have a desired color toner 8 attached to their surface, and are placed close to the photoreceptor 11 during development. 3c, rolls 4a, 4b, and 4c that are arranged in parallel with each of the developing rolls 3a to 3c and rotate together with the rolls to promote toner adhesion, and a toner layer is uniformly formed on the surface of each of the developing rolls 3a to 3c. blades 5a, 5b, 5c that form a toner layer uniformly on the surface of each of the rolls 4a to 4c;
It is composed of 6b and 6c.

In the above configuration, in the case of color copying, cyan toner is enclosed in the developing machine 1a, magenta toner is enclosed in the developing machine 1b, and yellow toner is enclosed in the developing machine 1c. The developing machines 1a to 1c are selected depending on the type of filter attached to a scanning section (not shown). That is,
Developing machine 1a is selected when exposure is performed through a red filter, and developing machine 1a is selected when exposure is performed through a green filter.
b. When the blue filter is selected, the developing device 1c is selected. First, a color original is scanned through a red filter, a first latent image is formed on the photoreceptor 11, and the developing machine 1
Cyan is developed by a. In the case of one-component development, by applying a predetermined bias voltage to the developing roll 3a, the toner on the roll surface is
It adheres to the surface of the photoreceptor 11 at a distance of 0.5 mm, and a visible latent image is formed. The cyan development is transferred to copy paper wrapped around a transfer drum. Then,
A second latent image is created through the green filter, and this latent image is developed into magenta by the developing machine 1b, followed by a second transfer onto the copy paper still wound around the transfer drum. Color is created by mixing two colors. Furthermore, a third latent image is created through a blue filter, this latent image is developed in yellow by the developing machine 1c, and the third transfer is performed on the copy paper to create a color similar to the original. You can get a copy.

In conventional developing devices, regardless of whether it is one-component development or two-component development, the developer is a powder mainly composed of toner. There was a risk that developer would scatter from the opening of the machine. Furthermore, since the developer is constantly in contact with the outside air through the opening, there is a risk that the developer will become damp under high humidity conditions and the properties of the developer may deteriorate.

Therefore, in order to prevent powder developer such as toner from leaking and scattering during periods other than during development operation, a developing device equipped with a shielding mechanism at the opening of the developing device was developed.
No. 56-8006, Japanese Utility Model Application No. 152742, Japanese Unexamined Patent Publication No. 136062, Japanese Unexamined Patent Publication No. 134663,
Each of these is disclosed in Japanese Patent Application Laid-open No. 172660/1983.

[Problem that the invention seeks to solve]

However, the disclosed shielding structure for the opening of the developing device requires special means for opening and closing the shielding member, has a large number of parts, and has a complicated structure.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a developing device having a simple structure and a shielding structure that can reliably prevent toner from leaking out of the device, scattering, and deterioration except when the developing device is in operation.

[Means for Solving the Problems] The developing device of the present invention stores a powder developer such as toner in a dividing plate, and each developing machine is equipped with a developing roll exposed on the outside and rotated around a rotating shaft. A plurality of developing machines are arranged on the circumference, a cylindrical housing having an opening opening in the longitudinal direction and accommodating the developing machines, and each having a curvature along the inner circumference of the housing. A shielding body larger than the opening size of the housing is provided around the outer periphery of the dividing plate excluding the exposed surface of the developing roll of each developing machine, and the developing machine and the shielding body are rotatably placed inside the housing. In addition to being supported, the developing device and the shielding body are configured to stop rotating at a position where the shielding body closes the entire opening of the housing when copying is completed or the power is turned off.

In the developing device of the present invention, the opening of the housing housing the developing machine is shielded by a shielding body except when the developing rolls of the individual developing machines housed inside are aligned;
Prevents toner inside the casing from leaking to the outside and scattering. In particular, when copying is finished or when the power is turned off to end operation of the copier, the shielding plate, which is larger than the opening in the housing, stops at a position where it closes the entire opening in the housing from the inside. The opening is reliably closed by a shield, and even when the copying machine is moved or replaced, developer such as toner does not scatter to the outside of the device, and the developer carried on the developer roll The developer does not come into contact with the outside air when copying is completed or the power is turned off [Example] Hereinafter, a developing device according to the present invention will be described in detail with reference to the drawings.

FIG. 2 shows an embodiment of the present invention, in which the developing device is a cylindrical developing device that houses a plurality of developing machines (four developing machines in this example) inside and has an opening 21 in the longitudinal direction of a part. A housing 22, a shaft 23 rotatably disposed in the longitudinal direction of the center of the housing 22, and a dividing plate 24 rotatably attached to the shaft 23 within the housing and dividing the developing machines according to the number of developing machines. Developing rolls 25a to 25d are arranged in parallel in the radial direction in a chamber partitioned by a dividing plate 24, and have negatively charged toner attached to their surfaces by friction between a pair of rolls, and an exposed surface of each developing roll. A shielding body 2 having a curvature along the inner circumference of the housing 22 except for
6a to 26d. In addition, the dividing plate 24
The space formed by the developing rolls 25a-2
5d forms developing machines 30a to 30d.

In the above configuration, the second
The operation will be explained based on the figure and FIG. 3 showing the undeveloped state.

During development operation, the shaft 23 is rotated so that a developing device equipped with a toner color corresponding to the exposure content is brought to the developing position. For example, when the developing device 30a is selected, the developing roll 25a is arranged to face the photosensitive drum 11 through the opening 21, and the interval between them is
It is set to 0.1~0.5mm. When a latent image is formed on the photoreceptor drum 11 in this state, the developing roll 25a rotates accordingly, and an appropriate bias voltage is applied to remove the toner 3 attached to the surface of the developing roll 25a. is the photosensitive drum 11
The toner flies towards the toner and adheres to the latent image surface, which is at an opposite potential, forming a visible image. The next developer is selected before the second exposure (for example, developer 30d)
Then, the shaft 23 rotates each developer and the shield together in the counterclockwise direction, positions the developing roll 25d on the developing surface, and performs the second development. onwards,
Similarly, when selecting other developing devices, by rotating the shaft 23, a developing device with a desired toner color can be selected.

Note that the developing rolls 25a to 25d are set extremely close to the photoreceptor surface in order to maintain a distance of 0.1 to 0.5 mm, and come into contact with the shields 26a to 26d when the developing machine rotates. It turns out. Therefore, when the developing machine rotates, as shown in FIG. 2, the developing machine is moved toward the center to avoid interference with the shielding body and to prevent it from interfering with the rotation. Then, after positioning, only the developing device that is the object of development is driven to the outside in the radial direction.

When not developing, the shaft 23 rotates from the developing position to a certain angle as shown in FIG. The rotation is stopped at the position shielded by 26d). This rotational drive is
This is executed by a drive section (not shown) in conjunction with the copying operation of the copying machine or when the power is turned off.

〔Effect of the invention〕

Since the developing device of the present invention is covered with a cylindrical casing, the developing machines other than the one in operation that fit into the opening of the casing do not come into direct contact with the outside air, providing excellent airtightness. This prevents deterioration of the developer and stabilizes it. Furthermore, since the developing machine, which is rotatably disposed inside the housing, has a shielding body larger than the opening of the housing integrally disposed around the outer periphery of the dividing plate, it is easy to operate the copying machine. The shielding body, which rotates inside the housing in conjunction, automatically closes the opening of the housing except when copying is in progress when the developing machine is in a position that matches the opening of the housing. To completely prevent developer such as toner from a developing device from scattering to the outside of the developing device. In addition, since the developing device is covered with a housing whose opening is completely closed with a shield when the developing device is not in operation, the developer carried inside the developing device or on the developing roll does not come into direct contact with the outside air. This solves the conventional problem of deterioration of development characteristics due to exposure to moisture. Furthermore, since the rotation of the shield is linked to the copy operation, there is no need to install special means for opening and closing the opening of the housing. Furthermore, the opening/closing control of the housing opening is determined by the rotation of the developing machine.
The control mechanism becomes simple. In particular, when copying is completed or the power is turned off, the shield stops rotating at the position where it closes the entire opening of the housing, so the movement of the copying machine,
To reliably prevent powdered developer such as toner from scattering to the outside during transfer or replacement, and to prevent developer carried on a developing roll from coming into contact with the outside air.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of a conventional developing device.
FIGS. 2 and 3 are cross-sectional views showing one embodiment of the present invention during development and during non-development. Explanation of symbols, 11... Photosensitive drum, 21... Opening, 22... Housing, 23... Shaft, 24... Dividing plate, 25
a to 25d... Developing roll, 26a to 26d... Shielding body, 30a to 30d... Developing machine.

Claims (1)

[Scope of Claims] 1 A plurality of individual developing machines each containing a powder developer such as toner in a dividing plate and each having a developing roll exposed on the outside are arranged on a circumference around a rotating shaft. a cylindrical casing having an opening opening in the longitudinal direction and accommodating the developing machine; and a curvature along the inner periphery of the casing; a shielding body integrally disposed around the outer periphery of the dividing plate of the developing machine excluding the exposed surface of the roll and having a size larger than the opening size of the housing, the developing machine and the shielding body being connected to the housing; A developing device is rotatably supported within the copying machine in conjunction with the copying operation of the copying machine, and configured to stop rotating at a position where the shielding body shields the entire opening of the housing when copying is completed or the power is turned off.