JP2579786B2 - Image forming device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electronic copying machine having a toner collecting unit.

2. Description of the Related Art There is known an image forming apparatus in which a belt-shaped or drum-shaped photoconductor is opposed to a transfer belt that conveys a transfer material, and a toner image formed on the photoconductor is transferred to a conveyed transfer material. ing. In such an image forming apparatus, various techniques for collecting residual toner after transfer on a photoreceptor have been proposed. One of the techniques is to collect toner on both sides of a transfer belt. Japanese Patent Application Laid-Open No. Sho 62-49370 proposes a technique in which a toner conveying belt is provided, and while the toner collected from the photoreceptor is conveyed by a conveying screw, the toner is dropped on the toner collecting conveying belt and collected. reference).

This conventional example has some excellent advantages, but on the other hand, it requires a dedicated toner conveying means for conveying the toner on both sides of the transfer belt, which complicates the apparatus configuration and increases the transfer efficiency. Since extra space is required on both sides of the belt, the entire apparatus is likely to be bulky. Further, both sides of the transfer belt may be constantly stained with toner, and the hands and the like may be stained when removing jammed paper. Further, since the collecting bottles are provided on both sides for each of the toner collecting conveying belts, when collecting the toners of these collecting bottles collectively, some kind of conveying means for merging them is required.

An object of the present invention is to provide an image forming apparatus which has solved the above-mentioned problems.

To achieve the above object, the present invention provides an image carrier having a surface on which a toner image is formed, a transfer belt for conveying a transfer material to a transfer position for transferring the toner image on the image carrier, and an image carrier. A cleaning device that removes residual toner after transfer on the body, temporarily stores the toner in the toner pool, collects the toner, releases the toner pool, and drops the toner onto the transfer belt. An image forming apparatus comprising: a toner collecting unit that removes and collects dropped toner from a transfer belt and stores the removed toner.

Examples Hereinafter, the present invention will be described based on one example.

FIG. 1 shows an embodiment in which the present invention is applied to a color copying apparatus.

First, a copying process performed by the copying apparatus will be described.

An original (not shown) on the original mounting table 1 is illuminated by an illumination unit including an illumination lamp 3 and a reflector 4, and the reflected light is reflected by a first mirror 11, a second mirror 12, and a third mirror.
The light is guided to the sixth mirror 16 via the 13, fourth mirror 14, lens 2, and fifth mirror 15. The sixth mirror 16 is a reflecting mirror coated with a multilayer film, and reflects any one of blue light, green light, and red light in white light,
The other two component lights are designed to be transmitted.

On the transfer belt 54, three photosensitive belts 53, 53 ', 5
The photoreceptor belts 53 'and 53 "constitute an example of an image carrier having a surface on which a toner image is formed, as will be described later.

Now, assuming that the light reflected by the sixth mirror 16 is blue light, this blue light reaches the third photosensitive belt 53 of the three photosensitive belts, and forms an original image at the blue light projection position 21. Image. On the other hand, the green light and the red light transmitted through the sixth mirror 16 reach the seventh mirror 17, and if this reflected light is assumed to be green light, this green light reaches the second photosensitive belt 53 '. The document image is formed at the green light projection position 22. The seventh mirror 17 is a reflecting mirror coated with a multilayer film like the sixth mirror 16, and reflects green light and transmits red light by the performance of the multilayer coating layer. The red light transmitted through the mirror 17 reaches the first photosensitive belt 53 "by the mirror 18, and forms an original image on the red light projection position 23.

In the above-described color separation process, the third photosensitive belt
It has been described that blue light is exposed to 53, green light is exposed to the second photoreceptor belt 53 ', and red light is exposed to the first photoreceptor belt 53 ". , Wavelength energy distribution of light source, transmitted light characteristics of lens,
An optimal method and order should be adopted depending on the sensitivity characteristics of the photoconductor, the transparency of the toner, and the like.

At the time of image formation, the third to first photosensitive belts 53 to 53 ″
Is driven in the direction of the arrow by the clockwise rotation of each of the drive rollers 51 to 51 ″.
The charge is removed by the quenching lamps 41 to 41 ", and then the entire surface is charged by the main chargers 43 to 43".
Now, 43 to 43 ″ are, for example, a charging device having a solid electrode (Solid State Charger = SSC).
Contributes to high reliability. Reference numerals 42 to 42 "denote erasers of an LED array, for example, for selectively erasing charges outside the image forming area.

Then, at each of the light projection positions 21, 22, and 23, an original image exposure color-separated into blue light, green light, and red light is simultaneously received. Exposure scanning of a document is the same as that of a normal copying optical system, but the difference is that the document scanning mirror is usually one sheet, whereas in this apparatus,
The first mirror 11 and the second mirror 12 are two pairs. This is because it is impossible to increase the number of reflecting surfaces on the dimension downstream of the lens. The exposure scan of the original is the first
The mirror 11, the second mirror, and the block of the illumination system, and the blocks of the third mirror 13, the fourth mirror 14 are moved to the positions indicated by broken lines at a speed ratio of 2: 1 to complete the operation. As a result, color-separated electrostatic images are formed on the respective photoreceptor belt surfaces.

Next, in the developing step, since the third photoreceptor belt 53 has been subjected to blue exposure, the developing device 61 forms a toner image with yellow toner having a complementary color relationship with the third photoreceptor belt 53. Next, similarly, since the second photoreceptor belt 53 'has been subjected to green exposure, the developing device 61' forms a toner image with magenta toner having a complementary color relationship therewith. Also, the first
Since the photoreceptor belt 53 "has been subjected to red exposure, the developing device 61" forms a toner image with cyan toner having a complementary color relationship with the developing device 61 ".

The photoreceptor surface on which these toner images are formed is subjected to a charge removing operation by pre-transfer charge removers 64, 64 ', 64 ", respectively, and proceeds to respective transfer positions 21', 22 ', 23'. The timing at which each toner image reaches the transfer position is designed so that each toner image is transferred to the same position on the transfer paper.

On the other hand, the transfer paper 70 as the transfer material is sent by the paper feed roller 71 to the pair of registration rollers 72 and 73, where the second
In order to match the tip of the toner image on the photoreceptor belt 53 ″,
The toner is supplied onto the transfer belt 54 while being lightly pressed by the press roller 74 at a certain timing.

The transfer belt 54 includes a transfer belt driving roller 55 and a roller 56.
It is stretched between, and by the counterclockwise rotation of the drive roller 55,
Driven in the direction of the arrow. At this time, the transfer belt 54
At each of the transfer positions 21 ', 22', and 23 ', each photoreceptor belt is securely contacted, and the transfer is reliably performed. In addition,
For further close contact, an assist roller (not shown) that presses from the inside of the transfer belt may be provided.

The transfer paper supplied onto the transfer belt 54 is conveyed on the belt, reaches the transfer position 23 'of the first photosensitive belt 53 ", and the cyan toner image is transferred by the transfer charger 63", and is sequentially transferred. At the position 22 ', the magenta toner image on the second photoreceptor belt 53' is transferred, and at the transfer position 21 ', the yellow toner image on the third photoreceptor belt 53 is overlaid by the respective transfer chargers 63', 63. Will be done. As a result, cyan and cyan appear on the transfer paper passing through the transfer position 21 '.
This means that a magenta and yellow superimposed image has been obtained.

As described above, the transfer belt 54 includes the photosensitive belts 53, 53 ',
Transfer position for transferring the toner image on the 53 "image carrier
The transfer material consisting of the transfer paper 70 is transported to 21 ', 22', and 23 '.

The transfer paper that has passed the transfer position 21 'is separated from the transfer belt 54 at the drive roller 55, where the toner image is fixed by the fixing device 75, and is discharged onto the paper discharge tray 76 to obtain a full-color copy. Further, as described later, the transfer belt 54 is cleaned, and thereafter, the charge is removed by a charge removing device 65 using an AC double corona to prepare for the next transfer.

In FIG. 2, the reference numeral 53 designates the last photosensitive belt shown in FIG.
On the left side of the lower part of the figure, the residual toner after transfer on the image carrier composed of the photoreceptor belt 53 is removed and temporarily stored in the toner reservoir 31, and when the toner is collected, the toner reservoir 31 is released. A cleaning device 25 that drops the toner onto the transfer belt 54 is provided.

The cleaning device 25 includes a cleaning blade 26, a shield roller 27,
28 and a bottom plate 29, respectively.

The residual toner on the photoreceptor belt 53 is scraped off by the cleaning blade 26 under the backup by the backup roller 32 inside the belt. Thus, the photoreceptor belt 53 is ready for the next copy. Below the cleaning blade 26, a shield roller 27, which is lined with a pressure plate 33 and prevents the toner from spilling out of the cleaning device, is provided.

The shield roller 27 rotates along with the movement of the photoreceptor belt 53, and moves the toner scraped off by the cleaning blade 26 to the left on the surface thereof. Then, the moved toner is separated from the surface of the roller 27 by the blade 28, and the toner pool 31 formed by the bottom plate 29 is formed.
Once stored.

In the conventional ordinary cleaning device, there is a device for carrying the toner out of the cleaning device in the axial direction of the roller, such as a screw conveyor.

On the other hand, in the present embodiment, in order to carry the toner out of the cleaning device, the toner reservoir 31 is released when the toner is to be collected.

That is, the bottom plate 29 forming the toner reservoir 31 is rotated to a virtual line position by a driving unit (not shown) such as a cam or a solenoid, so that the toner reservoir 31 is in a bottomless state, and The toner collected in the pool 31 falls onto the transfer belt 5.

The dropped toner is conveyed by the transfer belt 54, is finally scraped off and collected at a cleaning blade indicated by reference numeral 34, and then stored in the toner collection container 35.

As described above, the cleaning blade 34, the toner collecting container 35, and the like constitute one configuration example of a toner collecting unit that removes, collects, and stores the toner dropped on the transfer belt 54 from the transfer belt.

Further, in the illustrated example, the cleaning blade 34 and the toner collecting container 35 also serve as a belt cleaning device that cleans the toner adhered to the transfer belt 54 after the transfer process, and collects and stores the toner.

Although only one toner collecting means as described above is provided on the left end side of the transfer belt 54, the cleaning device 25
Is provided for each photosensitive belt. FIG. 1 shows the cleaning devices 25 ', 25 "
It is shown with a. The structure and operation of these devices 25 'and 25 "are the same as those of the cleaning device 25 described above.

The operation of dropping the toner from the toner reservoir 31 onto the transfer belt 54 is performed when there is no transfer paper below the cleaning devices 25, 25 ', 25 ". Alternatively, the operation will be performed after passing, but if there is not enough time to drop the toner in a transfer belt shape at the time of continuous copying of many sheets, etc., without forcibly operating during continuous copying, The operation may be performed after the end of the continuous copying, or when the number of the continuous copying is extremely large, the continuous copying operation may be temporarily interrupted to be operated. It is also possible to set a very small amount.

As for the timing for dropping the toner onto the transfer belt 54, it is easier to perform the cleaning devices 25, 25 ', and 25 "simultaneously, both mechanically and in terms of control. However, in this case, Since a large number of belt surfaces for toner conveyance are required, toner is concentrated in the same place on a relatively small area of the transfer belt with the timing of each of the cleaning devices 25, 25 ', and 25 ". You may make it fall. In addition, the cleaning devices 25, 25 ', 25 "
A suitable vibrating mechanism may be attached to the cleaning device in order to promote the fall of the toner from the cleaning device.

According to the above-described image forming apparatus of the present example, a dedicated toner conveying unit such as a screw conveyor for carrying out the toner from the cleaning device is not required, the entire configuration can be simplified, and the entire image forming apparatus can be reduced in size. Can be realized. In addition, the problem that the transfer belt is constantly stained with toner can be avoided. In addition, since the locking phenomenon of the toner by the screw conveyor is eliminated, the reliability in collecting the toner can be improved. In addition to collecting the toner from the image carrier, it is possible to collect the toner on the transfer belt as a whole, so that the configuration can be simplified, and maintenance needs to be performed sporadically. Absent. Further, the toner collecting means can be provided over the entire width of the belt. For example, if the collecting means and the entire width thereof are provided, the number of collecting containers can be increased, and the toner collecting interval can be set long.

As described above, a specific example in which the present invention is applied to a color copying machine having a plurality of image carriers is described. However, the present invention can be applied to a copying machine having only one image carrier or various other image forming apparatuses. Of course.

Advantageous Effects According to the present invention, a dedicated conveying unit for discharging toner from the cleaning device is not required, so that the toner discharging configuration can be simplified, and the entire image forming apparatus can be reduced in size. is there. Further, it is possible to prevent the transfer belt from being constantly stained with toner.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG. 2 is a diagram showing the configurations of a cleaning device and a toner collecting unit in the embodiment. 21'22'23 'Transfer position 25, 25', 25 "Cleaning device 31 Toner pool, 54 Transfer belt

Claims (1)

(57) [Claims] An image bearing member having a surface on which a toner image is formed;
A transfer belt that conveys a transfer material to a transfer position where the toner image on the image carrier is transferred; and a process in which residual toner after transfer on the image carrier is removed and temporarily stored in a toner reservoir to collect the toner. A cleaning device for releasing the toner pool to drop the toner onto the transfer belt; and a toner collecting means for removing, collecting, and storing the toner dropped on the transfer belt from the transfer belt. Image forming device.