JPH07120107B2 - Image forming device developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus utilizing an electrostatic transfer process, such as an electrostatic copying machine and a printer, and more particularly to a developing apparatus thereof. is there.

(Problems to be explained with the related art) A developing device that supplies toner to an electrostatic latent image formed on the surface of an image bearing member to supply the toner to the toner image to form the visible toner image is often used. As is known, a magnet roller surrounded by a sleeve made of a non-magnetic material is placed in an opening facing the surface of an image carrier, and charged toner attracted to the sleeve surface by magnetic force is rotated around the sleeve. It is usually constructed such that the latent image is converted into a visible image by moving the image to sequentially guide it to the opening and transfer it to the image carrier by the action of the electric field at this position.

In such a developing device, it is advantageous from the viewpoint of maintenance to supply a large amount of toner into the developing device at one time, but the charge amount of the toner particles is locally biased, or the toner pressure in the container is reduced. Therefore, there is a problem that the toner to be adsorbed and conveyed to the sleeve is prevented from adhering to the sleeve.

In order to avoid such a situation, the developing device is substantially separated into a hopper portion that accumulates toner and a developing portion that includes a sleeve and that supplies toner to the latent image on the image bearing member, and between the two. A toner replenishing means is arranged, and the toner amount is detected by a toner sensor arranged in the developing portion, and when the toner amount reaches a predetermined amount, the replenishing means is operated to sequentially control the toner from the hopper portion. Are gradually being prized.

In such a developing device, the amount of toner stored in the developing unit is 100 gr
When the amount of toner is reduced to about 90 gr, it is controlled so that the toner is replenished from the hopper to the developing unit by several gr to 20 gr at a time so that the toner is not insufficiently charged or unevenly distributed. It is possible to carry out stable image forming operations without causing deterioration of image quality due to improper supply, and the toner replenishment amount, which was conventionally suppressed to about 400 gr at a time, can be increased up to kg unit. Since it can be increased, it is becoming particularly advantageous for maintenance of high-speed machines.

Of course, with such a means alone, the toner is not initially supplied when a new developing device with an empty developing section is installed by replacement without installation, so when the developing device is installed in the image forming apparatus main body, Since it is necessary to forcibly supply toner to the developing unit, a developing device installation mode is added and the operator specifies the mode to operate the replenishing means of the developing device to supply an appropriate amount of toner to the developing unit. It shall be.

This makes it possible to obtain a high-quality image from the beginning, but due to an operator's erroneous operation, erroneous operation of the control unit itself, etc., the control unit is in the installation mode regardless of whether toner is present in the developing unit. It is unavoidable that the toner of No. 3 is supplied to the developing unit and the toner agglomerates to cause the image density not to appear.

The present invention has been made to cope with such a situation, and an object of the present invention is to provide a developing device capable of reliably preventing the inconvenience caused by an erroneous operation as described above.

(2) Configuration of the Invention (Technical Means for Solving the Problem and Actions Thereof) In order to achieve the above object, the present invention provides an image carrier carrying an electrostatic image and an electrostatic image on the image carrier. In an image forming apparatus having a developing device for developing and a hopper for storing toner to be supplied to the developing device, when the developing device is installed at a predetermined position of the device, the presence or absence of toner in the installed developing device is detected. When the detection result shows that there is no toner, a predetermined amount of toner is supplied from the hopper to the developing device, and when there is toner, an error display is performed.

With this configuration, when the toner is not present in the hopper or the developing unit of the developing device at the time of installation, the image forming apparatus is activated to disable image formation, or the toner is aggregated and solidified in the developing device. Therefore, it is possible to reliably prevent the occurrence of a situation such as deterioration of image quality and inability to form an image.

(Explanation of Embodiments) FIG. 3 is a schematic side view of a developing device suitable for applying the present invention. The developing device 1 is arranged in parallel to the position 2.

The developing device 1 is composed of a hopper portion 1a and a developing portion 1b, and a replenishing roller 5 for supplying toner from the hopper to the developing portion is arranged in a distribution portion formed on a boundary wall between the two. There is.

The developing portion 1b has an opening 5 at a portion facing the photoconductor 1.
Is formed, a part of the sleeve 4 surrounding the magnet roller 3 arranged in the developing section 1b is closely opposed to the surface of the photoconductor, and the toner detection sensor 7 is arranged at a proper position inside thereof. I am doing it.

In the illustrated apparatus, the magnet roller 3 is fixedly supported, and the sleeve 4 is rotated in the arrow B direction by an appropriate drive source (not shown).

With this configuration, the toner conveyed to the developing unit 1b by the replenishing roller 5 is charged by a method such as being agitated by an agitating member (not shown) and attached to the sleeve surface by the action of the magnet roller. , And will be guided toward the opening 6 as it rotates.

When reaching the opening, the toner adhering to the sleeve surface is cut off by the doctor blade 5, and then transferred to the electrostatic latent image formed on the surface of the photoconductor to form a visible toner image. Will be done.

The installation sequence according to the present invention applied to such a developing device will be described with reference to FIG.

As shown in the figure, when the installation mode is entered, the sensor 7 determines the presence / absence of toner in the developing section.

When it is detected that there is no toner, the replenishing motor is turned on and the replenishing roller 5 replenishes the toner to the developing portion for a predetermined time. At this time, the driving time of the replenishment roller 5 is
It depends on the amount of toner sucked into 1b and the toner flow rate from the replenishment roller.However, the amount of replenishment per unit time varies depending on the developing device. Slightly less than For example, the proper storage amount in the developing unit 1b is 100g.
In the case of r, it is good to set it to about 60 to 80 gr.

Next, the sleeve 4 is idled for a predetermined time to make the toner stand up, and the toner newly supplied from the hopper is sufficiently charged, and then the sleeve is stopped to end the installation sequence.

When the sensor detects the presence of toner at the initial stage, an error message is displayed in an appropriate place in the operator's viewing area and the installation mode is immediately terminated.

By defining such a sequence, it is possible to reliably eliminate accidents such as excessive toner supply due to erroneous operations.

FIG. 2 shows another embodiment of the present invention, in which a sensor is also arranged in the hopper unit 1a, and when this sensor confirms that the toner is present in the hopper. Only, it is configured to enter the sequence shown in the above embodiment.

That is, in this case, toner is replenished only when toner is present in the hopper and toner is absent in the developing unit, so it is possible to reliably prevent toner from being forgotten and excessive toner replenishment.

(3) Effects of the Invention As described above, according to the present invention, when the developing device is installed, there is no toner in the developing portion that directly contributes to the visualization of the electrostatic latent image, and it becomes impossible to form an image. In addition, it is possible to surely prevent excessive toner from being supplied thereto and impair the image quality, which is extremely effective in improving workability and maintainability.

Further, if necessary, it is possible to detect the presence or absence of toner in the hopper that supplies toner to the developing unit. Therefore, in addition to the above-described effectiveness, it is possible to reliably prevent an installation error.

[Brief description of drawings]

FIG. 1 is a diagram showing an installation sequence according to the present invention according to the present invention, FIG. 2 is a sequence showing another embodiment, and FIG. 3 is a view showing a developing device portion of an image forming apparatus suitable for applying the present invention. It is a sectional side view shown. 1 ... Developing device, 2 ... Image carrier, 3 ... Magnet roller, 4 ... Sleeve, 7 ... Sensor.

Claims (1)

[Claims] 1. An image forming apparatus comprising: an image carrier for carrying an electrostatic image; a developing device for developing the electrostatic image on the image carrier; and a hopper for storing toner to be replenished to the developing device. When a developing device is installed at a predetermined position of the apparatus, the presence or absence of toner in the installed developing device is detected, and if the detection result is no toner, a predetermined amount of toner is supplied from the hopper to the developing device. However, the image forming apparatus is characterized by displaying an error when toner is present.