JPH11249509A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent toner from soiling a periphery or splashing toward a human body when blown out by surely inhibiting the action of a toner carrying means when a developing means is drawn out. SOLUTION: When a developing means 4 is drawn out, a toner discharge pipe 38 and an air suction pipe 39 are automatically pulled out from an aperture. Since there is such possibility that the inside of a machine and a periphery are soiled by the toner and a worker breathes the toner as the toner is blown out from the end part of a tube when the toner carrying means is actuated, a means for inhibiting the action of the toner carrying means when the developing means 4 is drawn out is arranged. When a power source is turned on, it is judged first whether the developing means 4 is set at a prescribed position or not. When the developing means 4 is set at the prescribed position, the toner carrying means can be actuated. When it is not set at the prescribed position, the action of the toner carrying means is inhibited. By obtaining such a constitution, such a failure that the toner is scattered as the toner carrying means is actuated is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital copying machine,
The present invention relates to an electrophotographic image forming apparatus such as a printer, a facsimile, or a multifunction peripheral thereof.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, it is possible to collect toner remaining on an image carrier or the like after a transfer step by a cleaning means, and return the collected toner to a developing means for reuse. It has already been proposed. In an image forming apparatus provided with such a toner recycling mechanism, cleaning means removes toner that has been transferred onto a photoreceptor, but has not been transferred onto a transfer-receiving body, or toner remaining on a transfer belt. And a toner transfer means for transferring the collected toner from the cleaning means to the developing means.

[0003] Japanese Patent Application Laid-Open No. 7-2
No. 19329 discloses a screw having a rotor for rotating the toner of the developer in the axial direction by rotating, and a fixed stator having a passage inside which surrounds the rotor and being in contact with the rotor inside the passage. Pump and
There is disclosed an apparatus in which an air supply means for supplying air for fluidizing a developer moved by the screw pump is used to transfer a mixture of toner and air through a flexible pipe.

In this toner transfer means, the stored toner and the collected toner can be transferred through a flexible pipe or the like, so that the installation positions of the toner storage section and the toner collection section are not restricted at all and have a simple configuration. Therefore, there is an advantage that the toner can be surely transferred. Further, the toner transfer means using the screw pump is fluidized in a state of a mixture with air by the air supply means and transferred in a state, so that stable transfer of the toner can be obtained and unnecessary toner for the transferred toner is obtained. Aggregation and thermal fusion of the transferred toner are less likely to occur without applying more stress.

[0005] Under these circumstances, it can be seen that the toner transfer system using a screw pump is particularly excellent.
This screw pump is a single-shaft eccentric screw pump (commonly called a mono pump) composed of a female screw type stator having a double pitch spiral groove therein and a male screw type rotor rotatably fitted in the stator.

[0006]

Incidentally, in the image forming apparatus, in order to facilitate maintenance, it is desired that the developing means be unitized and detachably mounted on the apparatus main body. However, when the toner transfer unit is operated in a state where the developing unit is pulled out for maintenance, there is a problem that the toner blows out from the toner transfer pipe and contaminates the inside and outside of the image forming apparatus.
Furthermore, if the worker inhales the toner, the toner may be harmful to health, and it is necessary to prevent the toner from blowing out.

The present invention solves the above-mentioned conventional problems,
It is an object of the present invention to provide an image forming apparatus that can reliably prevent the toner transfer unit from operating when the developing unit is removed from a predetermined position of the image forming apparatus.

[0008]

In order to achieve the above object, the present invention is directed to developing an electrostatic latent image formed on an image carrier, which is detachably attached to a predetermined position of an image forming apparatus main body. And an image forming apparatus that transfers toner to be supplied to the developing unit as a mixture with a gas flow by the operation of a toner transfer unit having a screw pump and an air supply unit. In a state where the developing unit is set in the image forming apparatus main body,
A toner transfer pipe from the toner transfer means is directly connected, and an operation prohibiting means for prohibiting the operation of the toner transfer means when the developing means is not set at the predetermined position is provided. .

It is to be noted that the present invention is provided with a detecting means for detecting whether or not the developing means is set at the predetermined position. When the operation inhibiting means is controlled to be turned on / off by a detection signal of the detecting means, the effect is obtained. It is a target.

Further, the present invention has an electric connection tool which is connected only when the developing means is set at the predetermined position, and the operation prohibiting means controls the on / off control depending on whether or not the electric connection tool is connected. It is effective when done.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall schematic diagram showing a digital copying machine as an example of an image forming apparatus according to the present invention.

In FIG. 1, a digital copying machine employs a well-known electrophotographic system, and includes a drum-shaped photosensitive member 1 as an image bearing member inside. Arrow A around photoconductor 1
A charger 2, an exposure unit 3, a developing unit 4, a transfer unit 5,
Cleaning means 6 is provided.

When the copying process is started, an electrostatic latent image is formed on the photoreceptor 1 on the basis of an image signal read by the reading means 8 from a document placed on the document table 7 on the top of the copying machine. . The electrostatic latent image formed on the photoreceptor 1 is developed by a developing unit 4 to form a toner image, and the toner image is transferred to a transfer material fed from a paper feeding unit 9 by a transfer unit 5.
Is electrostatically transferred. The transfer material on which the toner image has been transferred by the transfer is conveyed to the fixing means 10, where it is fixed and then discharged out of the machine.

The toner adhered onto the photoreceptor 1 by the above-mentioned development is generally electrostatically transferred to a transfer material by the transfer means 5, but about 10% of the toner remains untransferred on the photoreceptor. The residual toner is scraped off from the photoreceptor 1 by a cleaning blade 6a and a brush roller 6b of the cleaning unit 6, and the scraped-off toner is returned to the developing unit 4 by a toner transfer unit to be described later. Become.

A cleaning means 11 is also provided on the transfer belt 5a of the transfer means 5 for contacting the non-transferred portion or the non-image portion of the photosensitive member 1 and adhering toner. The toner remaining on the transfer belt 5a is scraped off by a cleaning blade 11a which is in sliding contact with the belt. The scraped-off toner is also transferred to the developing unit 4 by a toner transferring unit described later.

In the copying machine of this embodiment, as shown in FIG. 2, toner for transferring the toner collected by the cleaning means 6 for the photosensitive member and the cleaning means 11 for the transfer belt to the developing means 6 is used. A transfer means 20 is provided, and the toner from the cleaning means 6 for the photosensitive member and the toner from the cleaning means 11 for the transfer belt are supplied to the toner transfer means 20 by toner discharge pipes 13 and 14, respectively.
Sent through. The toner transfer unit 20 has a screw pump 21 as a toner transfer unit and an air pump 22 as an air supply unit. By supplying air to the toner transferred by the screw pump 21, the toner is mixed with an air flow. It is configured to be transferred as air. One end of a toner conveying tube 23 made of a flexible hose or the like is fitted into the toner discharge port of the screw pump 21, and the other end is easily connected to a toner replenishing section 30 fixed to the developing means 4 described later. .

In FIG. 3, the developing means 4 is detachably mounted in the direction of arrow B, that is, in the front side of the machine, so that maintenance and the like can be easily performed.
Further, the developing means 4 is configured to be able to replenish toner when the toner concentration is reduced in the case of, for example, a two-component developing means by use. And in the case of this example,
Toner replenishment: fresh toner and recycled toner
There are three routes. First, replenishment of fresh toner will be described.

For toner supply, the toner detection sensor 34
However, when it is detected that the toner in the developing unit (not shown) is insufficient, a toner replenishment instruction is issued to the fresh toner replenishing unit 3.
3, the fresh toner replenishing unit 33 starts supplying toner to the toner replenishing unit 30. The toner replenished to the toner replenishing unit 30 is sequentially conveyed while being stirred to the back side (the direction opposite to the arrow B) by the rotation of the spiral agitator 31, and replenished to the developing unit. Then, when the toner detection sensor 34 detects that the toner concentration has reached the predetermined value, the toner supply command is released and the toner supply is stopped.

Next, the other end of the recycled toner is connected to a toner discharge pipe 38 fixed to the structure 12 of the image forming apparatus. Above the pipe 38, air suction pipes 39 are arranged vertically, and the pipe 39 is connected to the air intake of the air pump via the tube 24. The two pipes 38 and 39 are inserted into a connection part 37 having a space inside, which is provided to protrude from the upper surface of the toner supply part 30.

FIG. 4 is a sectional view showing the toner replenishing portion 30 of the developing means 4 shown in FIG. 3. The connecting portion 37 is provided separately from the fresh toner replenishing opening 32 of the toner replenishing portion 30. It is an introduction route exclusively for recycled toner,
The connection portion 37 is provided with openings 41 and 42 into which the toner discharge pipe 38 and the air suction pipe 39 are inserted. The openings 41 and 42, which are insertion portions, are provided with sealing members 43 and 44 made of elastic members, respectively, so that toner is not scattered from the openings.
Even when the air suction pipe 8 and the air suction pipe 39 are inserted, no gap is formed in the portion.

The toner discharge pipe 38 and the air suction pipe 39 are supported by the structure 12 of the image forming apparatus such that the axis is parallel to the direction in which the developing means 4 is attached and detached.
Therefore, the developing means 4 is moved by the arrow B for maintenance.
When the developing unit 4 is pulled out in the direction, it is separated from the toner discharge pipe 38, the air suction pipe 39, and the seal members 43 and 44 of the connecting portion 37, so that the developing unit 4 can be easily pulled out without any special operation. .

By the way, when the developing means 4 is pulled out,
The toner discharge pipe 38 and the air suction pipe 39 automatically fall out of the openings 41 and 42. At this time, if the toner transfer means operates, the toner blows out from the end of the tube, not only contaminating the inside of the apparatus and its surroundings, but also poses a risk that the worker may wear or suck the toner.

Therefore, in the present invention, an operation inhibiting means for inhibiting the operation of the toner transfer means 20 when the developing means 4 is pulled out is provided, and this means is controlled according to the flow shown in FIG.

In FIG. 5, when the power is turned on,
First, it is determined whether or not the developing means 4 is set at a predetermined position (step 1). If the developing means 4 is set at the predetermined position, the operation of the toner transfer means 20 is enabled (step 2). If the developing means 4 is not set at a predetermined position, the operation of the toner transferring means 20 is prohibited.
(Step 3).

With this configuration, it is possible to reliably eliminate the problem that the toner transfer means 20 operates when the developing means 4 is pulled out and the toner is scattered.

Next, a specific method for judging that the developing means 4 has been pulled out will be described. 6, a detector 40 is provided in the main body of the image forming apparatus to turn on when the developing unit 4 is set at a predetermined position, and to turn off when the developing unit 4 is pulled out.
On / off control of the operation of the toner transfer means 20 is performed.

As another method, as shown in FIG. 3, in the sensor of the developing means 4 of the present embodiment, a connector 35 as an electrical connector is connected to a connector 36 of the image forming apparatus main body at the end of the cable. ing. Therefore, when pulling out the developing means 4, it is necessary to remove the connectors 35 and 36. Therefore, the presence / absence of the setting of the developing unit in the image forming apparatus can be easily detected from the connection / disconnection of the connectors 35 and 36, and the on / off control of the operation of the toner transfer unit 20 is performed based on the connection state of the connectors 35 and 36. Like that.

With this configuration, the dedicated sensor as in the above embodiment can be omitted. As described above, the preferred embodiments of the present invention have been described, but the present invention should not be limited to the above embodiments. For example, in the above embodiment, the collected toner is returned to the developing unit. However, a toner bank for supplying toner to the developing unit is provided,
The present invention can also be applied to a configuration in which toner is sent from a toner bank to a developing unit using a toner transfer unit.

In the above embodiment, the apparatus for transferring the toner collected by the photoconductor cleaning means and the transfer cleaning means together has been described.
The present invention may be configured such that only one of the photoconductor cleaning unit and the transfer cleaning unit transfers the collected toner. In particular, since the collected toner of the transfer cleaning unit contains foreign matter such as paper dust, the collected toner may be returned to the waste toner tank without being recycled.

[0030]

According to the first to third aspects of the present invention, it is possible to reliably prevent the toner transfer means from operating when the developing means is pulled out. Hanging can be prevented.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram illustrating an example of an image forming apparatus according to the present invention.

FIG. 2 is a perspective view showing an example of a toner transfer unit of the present invention.

FIG. 3 is a perspective view illustrating a toner replenishing unit of the developing unit of the present invention.

FIG. 4 is a sectional view of the toner transfer means.

FIG. 5 is a flowchart illustrating a control operation of the image forming apparatus of the present invention.

FIG. 6 is an explanatory diagram showing a method for detecting the presence / absence of the setting of the developing unit of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 4 Developing means 6, 11 Cleaning means 20 Toner transfer means 21 Screw pump 22 Air pump 35, 36 Connector 40 Detector

Claims (3)

[Claims] A developing means for developing the electrostatic latent image formed on the image carrier, the developing means being removably attached to a predetermined position of the image forming apparatus main body, and supplying the developing means to the developing means. In the image forming apparatus, the toner is transferred as a mixture with a gas flow by the operation of a toner transfer unit having a screw pump and an air supply unit, wherein the developing unit is set in the image forming apparatus main body. And an operation prohibiting means for prohibiting the operation of the toner transfer means when the toner transfer pipe from the toner transfer means is directly connected and the developing means is not set at the predetermined position. Image forming apparatus. 2. The image forming apparatus according to claim 1, further comprising a detection unit configured to detect whether the developing unit is set at the predetermined position, wherein the operation prohibiting unit is configured to detect the operation of the developing unit based on a detection signal of the detection unit. An image forming apparatus characterized in that on / off control is performed. 3. The image forming apparatus according to claim 1, further comprising: an electrical connector that connects only when the developing unit is set at the predetermined position, wherein the operation inhibiting unit includes the electrical connection unit. An image forming apparatus characterized in that on / off control is performed depending on the presence / absence of connection of a dynamic connector.