JPH02216174A - Cleaning device for image forming device - Google Patents

Abstract

PURPOSE:To stabilize an excellent image by arranging a cleaning means for nonmagnetic toner on the upstream side of that for magnetic toner. CONSTITUTION:A signal indicating that a developing unit 2 contains nonmagnetic toner and a signal bringing the developing unit 2 to an operational position close to a photosensitive body 1 are inputted. Simultaneously, a solenoid 14 is turned off, and a blade 11 abuts on the photosensitive body 1 by the action of a spring 15, whereby the nonmagnetic toner is removed from the developing unit 2. When the developing unit 2 retreats to an inoperable position, the nonmagnetic toner on the surface of the photosensitive body 1 is completely recovered by a cleaning device 6 after a lapse of a prescribed time. Then, the solenoid 14 is turned on to separate the blade 11 from the photosensitive body 1. When a developing unit 3 containing magnetic toner comes to the operational position under this condition, the magnetic toner attaching to the photosensitive body 1 is completely cleaned out by the cleaning device 7. Consequently, an excellent image can be obtained stably for a long time.

Description

Detailed Description of the Invention (1) Purpose of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus that utilizes an electrostatic transfer process, such as an electrostatic copying machine or a printer, and a cleaning apparatus therefor. It is.

(Prior art and issues to be solved) A well-known image forming method in which a process of electrostatically transferring a transferable toner image electrostatically formed on the surface of an image carrier onto a sheet-like transfer material such as a sheet of paper is repeated. In the device, during transfer,
It is necessary to sufficiently remove residual toner that does not contribute to transfer and remains on the image carrier each time transfer is performed. / A cleaning blade made of an elastic material such as tan rubber, which is configured to scrape off residual toner by pressing against the image carrier, is simple and cost-effective, and has an excellent toner removal function. As is well known, it has been widely used in practice.

However, after transfer, there is not only residual toner on the surface of the image carrier, but also foreign matter other than toner, such as paper dust generated from paper, which is the most commonly used transfer material, and corona products caused by the presence of high-pressure members in the device. However, the cleaning blade described above has a limited cleaning function against these foreign substances.

For this reason, when using a one-component magnetic toner,
Along with the cleaning blade, a magnetic roller is disposed near the cleaning blade, and the toner once collected in the cleaning device forms a magnetic brush on the surface of the roller and rubs the image carrier, thereby removing foreign matter as mentioned above. Measures have been proposed to remove it.

Such means not only effectively remove the various foreign substances mentioned above, but also supply toner little by little to the blade edge to create a lubricating effect even when no toner is present on the surface of the image carrier. The toner is electrostatically attached to the surface of the image carrier by applying mechanical force to the toner to weaken its adhesion, making it easier to remove the toner by the blade. Certain effects have been recognized.

By the way, in recent years, in addition to toner for obtaining black images,
Image forming apparatuses that are provided with separate developing devices that contain colorers and selectively use these to obtain multicolor images are increasingly being used.

The toner used in such devices is usually made of a transparent resin mixed with dyes, pigments, etc., and since the toner is non-magnetic, cleaning using a magnetic roller as described above is not possible. 1M even when applied to equipment
There is an unavoidable problem that a single brush is not formed and it becomes difficult to perform the desired cleaning action.

However, even in devices that can use color toner, copies of black images are usually made far more frequently than those of color images.
It is not advantageous to simply throw away the advantages of using a gunnet roller as described above.

From this perspective, the present applicant first supplied magnetic toner from the developing device to the cleaning device based on the information at the time of image formation with non-magnetic toner, thereby preventing toner shortage due to the use of non-magnetic toner. We proposed a device that would solve this problem.

In this way, even in a cleaning device that uses a magnetic roller as a cleaning means,
Although it has become possible to achieve the desired effect in avoiding the deterioration of the cleaning function due to the use of non-magnetic toner, it is immediately clear from the method that the magnetic toner is consumed in a manner that does not directly contribute to image formation. Therefore,
This is undesirable because the amount of toner consumed becomes excessive, which is disadvantageous in terms of running costs, and even in cartridge-type image forming apparatuses that are basically disposable, the amount of effective toner decreases.

The present invention has been made to deal with such a situation, and is a cleaning device for an image forming apparatus that uses 11fi toner and non-magnetic toner and uses a magnet to remove the magnetic toner. By collecting each toner specifically, a large amount of non-magnetic toner enters the surface of the magnet, preventing the formation of an E (1st brush) and ensuring a stable cleaning effect at all times. The object of the present invention is to provide a leaning device.

(2) Structure of the invention (technical means for solving the problem and its operation) A plurality of developing devices are provided opposite to a moving image bearing member, magnetic toner or non-magnetic toner is stored in each of the developing devices, and these developing devices are provided. In an image forming apparatus configured to selectively use a container, a means for cleaning non-magnetic toner is disposed upstream of a means for cleaning magnetic toner when viewed in the running direction of an image carrier. It is characterized by:

With this configuration, when a magnetic roller is used to clean the magnetic toner in an image forming apparatus that uses magnetic toner and non-magnetic toner, the function of the magnetic roller is prevented from being hindered by the presence of the non-magnetic toner. without consuming too much toner (
, it is possible to perform stable cleaning at all times.

(Description of an Embodiment) FIG. 1 is a side view of a main part showing an embodiment in which the present invention is applied to an image forming apparatus equipped with a rotating cylindrical photoreceptor. A first developing device 2 that stores non-magnetic toner and a carrier, and a second developing device 3 that stores l-component magnetic toner are arranged close to the photoreceptor 1 rotating in the direction of the arrow. By a control mechanism (not shown), one of these developing devices assumes an operating position close to the photoreceptor 1, while the other developing device assumes an inoperative position away from the photoreceptor.

When the electrostatic latent image formed on the surface of the photoreceptor l comes to a position facing the developing device in the operating position due to the action of a primary charger and image signal applying means (not shown), the electrostatic latent image is supplied by the developing device in the operating position. The latent image becomes a toner image by the toner, and when the transfer charger 5 reaches a transfer position facing the photoreceptor 1 as the photoreceptor 1 rotates, the toner image is transferred to the conveyance path 4 at the same timing. A transfer material (not shown) is brought to a transfer position, and by the action of the transfer charger 5, the toner image is transferred from the photoreceptor to the transfer material, and then separated from the photoreceptor 1 and transferred to a fixing site (not shown). shall be transported to.

On the other hand, residual toner remaining on the surface of the photoconductor 1 without being transferred to the transfer material during transfer is removed by a cleaning device 6 disposed on the upstream side as viewed in the traveling direction of the photoconductor. It is assumed that the particles are sequentially processed and removed from the surface of the photoreceptor 1 by a cleaning device 7 disposed on the downstream side.

The cleaning device 6 is for collecting non-magnetic toner, and has a cleaning blade 11 made of urethane rubber or the like disposed therein.

The blade 11 is pivotally supported by a support member 12 that is swingably supported by a support bin 13 attached to a fixed position in the cleaning device.
It shall be able to swing toward and away from the

The blade 11 is always biased toward the photoreceptor 1 by a spring 15 whose one end is fixed to the other end of the support member 12, and is also attached to the plunger of a solenoid 14, which turns the blade 11 on and off. It approaches and separates from the photoreceptor 1.

Reference numeral 16 is a scoop sheet that collects the toner scraped off by the blade 11, and reference numeral 17 is a rotating blade for sending the toner in the direction of the conveying screw 18.

The cleaning device 7 is equipped with an elastic cleaning blade 19 that presses against the surface of the photoreceptor 1, and a magnetic roller 20 on the upstream side.
is placed close to the photoconductor 1, and as described above, the mainly magnetic toner scraped off by the blade 19 is captured by the magnet roller 20 and conveyed to the back side of the cleaning device as the magnet roller rotates. Then, a predetermined amount of toner stands up by the toner layer thickness regulating roller 21, reaches a portion facing the photoreceptor 1 again, and rubs and cleans the surface of the photoreceptor.

It is assumed that the surplus toner at the position of the regulating roller 2I passes through the scraper 22 and reaches the position of the conveyance screw 24, whereupon it is discharged to the outside.

Next, the operation of the above device will be explained with reference to FIGS. 1 and 2.

In the apparatus shown in FIG. 1, it is assumed that the developing device 2 stores non-magnetic toner, a signal is input to bring the developing device to an operating position close to the photoreceptor 1, and the solenoid 14 is turned off. As a result, the blade 11 is brought into contact with the photoreceptor 1 by the action of the spring 15, and the non-magnetic toner coming from the developing device 2 is removed.

When the developing device 2 is retracted to the non-operating position, after a certain period of time, after all the non-magnetic toner on the surface of the photoreceptor is collected by the cleaning device 6, the solenoid 14 is turned on.
It is assumed that the blade 11 is separated from the photoreceptor 1.

FIG. 2 is a timing chart showing the above operation.

In this state, when the developing device 3 that stores the magnetic toner assumes the operating position, all magnetic toner adhering to the photoreceptor 1 is thereafter processed by the cleaning device 7 in the same manner as a known device. become.

When the blade 11 of the cleaning device 6 retreats, some toner remains attached to the photoreceptor 1, but since the amount is small, it does not particularly affect the cleaning action and is recovered by the cleaning device 7. .

FIG. 3 shows another embodiment of the present invention, and the cleaning device 7 for magnetic toner in this apparatus is not particularly different from that in the previous embodiment.

Reference numeral 8 in the figure is a cleaning device for non-magnetic toner. In this device, a fur brush 31 extending in the axial direction of the photoreceptor 1 comes into contact with the surface of the photoreceptor and is rotated by an appropriate drive source to remove residual toner. Toner shall be removed.

In the figure, reference numeral 32 is a flicker bar, 33 is a collecting electrode roller, 34 is a scrubber L for peeling off the toner adhering to the roller 33, and 35 is a bar for discharging the collected toner. It is a conveyance screw.

The cleaning device 8 is displaced in the direction of the double arrow Y shown in the figure by a control mechanism (not shown) to approach and separate from the photoreceptor 1, and its timing is the same as when the blade 11 approaches and separates from the photoreceptor in the above-mentioned embodiment device. The same shall apply.

In this case, it is of course possible to displace only the fur brush 31 instead of displacing the entire cleaning device 8.

(3) As described in detail, according to the present invention, in a cleaning device for an image forming apparatus that selectively uses magnetic toner and non-magnetic toner, magnetic toner Since the non-magnetic toner cleaning means is arranged upstream of the cleaning means of Since it can be cleaned well at all times, it greatly contributes to stably obtaining high-quality images over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an image forming apparatus to which the present invention is applied; FIG. 2 is a diagram showing a blade control sequence for non-magnetic toner; FIG. 3 is a side sectional view showing another embodiment. . 1... Photoreceptor, 2.3... Developing device, 6°7, 8...
・Cleaning device, 11.19...Cleaning blade, 14...Solenoid, 15...Spring, 20
...Magnetic roller, 31...Fur brush. 2nd 3rd

Claims (3)

[Claims] (1) Image formation in which a plurality of developing devices are provided facing a moving image carrier, magnetic toner or non-magnetic toner is stored in each developing device, and these developing devices are selectively used. A cleaning device comprising: a means for cleaning non-magnetic toner and a means for cleaning magnetic toner disposed upstream of a means for cleaning magnetic toner when viewed in the running direction of an image carrier. (2) The cleaning device according to claim 1, wherein the means for cleaning the non-magnetic toner is a cleaning blade disposed so as to be movable toward and away from the image carrier. (3) The cleaning device according to claim 1, wherein the means for cleaning the non-magnetic toner is a fur brush disposed so as to be able to move toward and away from the image carrier.