JPH05142973A - Image forming device - Google Patents

Abstract

PURPOSE:To miniaturize a cleaning means by predicting or detecting the quantity of a material stuck on a transfer material carrier and changing the feeding quantity of a cleaning web according to the quantity of the material. CONSTITUTION:The soiling condition (stuck quantity) of the surface of the dielectric transfer material carrying sheet 5f is predicted according to respective phenomena (for example, jamming time or the like) in an image forming process. According to the stuck quantity, the feeding quantity o the cleaning web 11a (the feeding quantity of the web 11a when a transfer drum 5a is rotated once at a cleaning action time) is changed. For example, the feeding quantity of the rotated in the case of warming-up) and before or after ordinary copying is set to be 1mm and the feeding quantity after the continuous copying and after feedback sequence is started is set to be 2mm. Besides, the feeding quantity a the jamming time is set to be 5mm. Then, the feeding mean of the cleaning means 11 is actuated based on the signal of the sequence of a copying machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a transfer material on a moving transfer material carrying sheet, and a transfer electric field is applied to the transfer material to form it on an image bearing member composed of a photoreceptor or an insulator. The present invention relates to a transfer device for superposing and transferring a toner image on the transfer material, and can be suitably used as a transfer device such as an electrophotographic copying machine or a printer.

[0002]

2. Description of the Related Art As described above, the toner image on the image carrier is transferred to the transfer medium by facing the image carrier such as a photoreceptor or an insulator having the toner image once or a plurality of times. Various image forming apparatuses such as electrophotographic copying machines and printers for obtaining a black and white or color image are commercially available and many have been proposed.

FIG. 4 shows an example of a color electrophotographic copying machine for forming a full-color image.

In this example, the color electrophotographic copying machine is
A drum-shaped electrophotographic photosensitive member which is an image carrier, that is, a photosensitive drum 1 is rotatably supported in the direction of an arrow, and a corona charger 2, an exposure optical system 3, a developing device 4, and a transfer device are provided around the photosensitive drum 1. 5, the cleaning device 6 is arranged.

The optical system 3 is composed of an original scanning section 3a and a color separation filter 3b, and a photosensitive drum 1 uniformly charged by a charger 2 is irradiated with an optical image for each separated color image to form a latent image. To do. The developing device 4 is a rotary developing device, and four developing devices, that is, a yellow developing device 4Y, a magenta developing device 4M, a cyan developing device 4C, and a black developing device 4B are arranged around a central axis 4b, and a predetermined developing device is provided. Is rotated to a developing position facing the photosensitive drum 1 to develop the latent image on the photosensitive drum 1, and a toner image is formed on the photosensitive drum 1.

Further, the toner image on the photosensitive drum 1 is transferred from the transfer material cassette 7 to the transfer material supplied to the position facing the photosensitive drum 1 via the transport system and the transfer device 5. In this example, the transfer device 5 includes a transfer drum 5a, a transfer charger 5b, and a transfer material gripper 5 that grips and conveys the transfer material.
c, an inner charging device 5d, and an outer charging device 5e, and a transfer material carrying sheet 5f made of a dielectric material is stretched in a cylindrical shape in a peripheral opening area of the transfer drum 5a. The carrier sheet 5f is integrally provided.

To explain further, the toner image on the photosensitive drum 1 is transferred by the transfer charger 5b to the transfer material carrying sheet 5f as the transfer device having a drum shape as described above, that is, the transfer drum 5a is rotated. The transfer material is transferred onto the material, and at the same time, the transfer material is adsorbed to the transfer material carrying sheet 5f. After the residual toner is removed from the photosensitive drum 1 by the cleaning device 6, the next image forming process is continuously performed.

In this way, a desired number of color images are transferred to the transfer material that is sucked and conveyed by the transfer material carrying sheet 5f, and a full color image is formed. Since such a color image forming method is well known to those skilled in the art, further description will be omitted.

When the transfer of the four color toner images is completed in this way, the transfer material is separated from the transfer drum 5a and discharged onto the tray 10 via the heat roller fixing device 9.

As described above, in the color electrophotographic copying machine, the transfer drum 5 is provided with the transfer material carrying member for holding the transfer material, that is, the transfer material carrying sheet 5f made of a dielectric material, in the peripheral opening thereof. The transfer drum 5a is stretched.
A unit group that holds or stores the developer (toner) such as the photosensitive drum 1, the developing device 4, and the cleaning device 6 is arranged in the vicinity of the peripheral surface of, and the unwanted toner scattered from the unit group is attached. By doing so, the transfer material carrying sheet 5f on the transfer drum 5a may be soiled. Furthermore, when the transfer material is jammed (the transfer material is jammed in the machine) when separating the transfer material from which the toner image has been transferred and which has not been fixed yet from the transfer drum 5a, the transfer material Toner on the transfer material adheres to the carrying sheet 5f, and the transfer material carrying sheet 5f is heavily soiled by the toner.

Therefore, the transfer device 5 is provided with a transfer material carrying sheet cleaning means 11 for the purpose of removing the toner adhering to the transfer material carrying sheet 5f. Transfer material carrying sheet 5
Cleaning of f is normally performed on the transfer drum 5 prior to transfer.
It is performed at the time of pre-rotation of a, but as described above, it is performed at any time after the transfer material is jammed or the like.

As shown in FIG. 4, the transfer material carrying sheet cleaning means 11 is stretched around the peripheral opening of the transfer drum 5a, which is a cylindrical transfer material carrying sheet supporting means in this example. A roll-up type cleaning web 11a is provided outside the transfer material carrying sheet 5f, and a backup brush 11b is provided inside.

The cleaning web 11a is wound around a pay-out roll 11c so as to be rotatable and transfer material carrying sheet 5
The web pressing roller 11d, which is pressed by f, is wound around the web pressing roller 11d and the transfer material carrying sheet 5f so as to be wound up by the winding roll 11e. Is to wind a cleaning web 11a of a constant length at a constant timing by a drive source (not shown). Then, by the rotation of the transfer drum 5a, the transfer material carrying sheet 5f made of a dielectric material is cleaned at the position of the web pressing roller 11d.
The transfer material carrying sheet 5f rubs against the cleaning web 11a at the position of the web pressing roller 11d, so that the adhering substances such as toner adhering to the transfer material carrying sheet 5f are wiped off to the cleaning web 11a. ing. The cleaning web 11 is applied to the film-shaped transfer material carrying sheet 5f by the web pressing roller 11d.
In order to prevent deformation due to pressure applied via a,
Backup brush 11b on the web pressing roller 11d
Are facing each other.

[0014]

However, in the above-mentioned conventional example, the feeding amount of the cleaning web is constant, and when the amount of adhered substances such as toner is the maximum (for example, when jammed, the toner on the photoconductor directly causes a dielectric loss). (When transferred to the body sheet), so that sufficient cleaning power can be obtained,
The feed amount is determined. As a result, the adhering substances such as toner on the transfer material carrying sheet are completely cleaned, but in such a case, the feed amount of the cleaning web becomes the longest, the total length of the cleaning web becomes long, and the cleaning means becomes large, or However, there was a drawback that it was forced to replace it in a short period of time.

[0015]

According to the present invention, an image carrier having a toner image and a transfer material for transferring the toner image are held, and the transfer material is guided to a transfer position of the image carrier. In an image forming apparatus provided with a transfer material carrying member for cleaning, a cleaning web contacting the transfer material carrying body, and a cleaning web feeding means, the amount of deposits on the transfer material carrying body is predicted or By having a means for detecting and changing the feed amount of the cleaning web according to the amount of the adhered matter, the cleaning means can be downsized.

[0016]

Embodiments of the transfer device according to the present invention will now be described in more detail with reference to the drawings.

[First Embodiment] The transfer apparatus according to the present invention can be used in various image forming apparatuses and can have various configurations. In this embodiment, the transfer apparatus described with reference to FIG. 4 is used. This will be described with reference to FIG. The transfer device 5 is a transfer material carrying sheet supporting means having a cylindrical shape, that is, the transfer drum 5.
a, a transfer charging device 5b, a transfer material gripper 5c that grips and conveys the transfer material, an inner charging device 5d, and an outer charging device 5e, and a dielectric transfer material is provided in the peripheral opening area of the transfer drum 5a. A carrier (sheet-shaped transfer agent carrying sheet in this embodiment) 5f is stretched, and the transfer drum integrally has the sheet 5f. The cleaning means 11 for the transfer material carrying sheet is the same as in the conventional example as shown in FIG. 4, and the description thereof is omitted.

Here, as the cleaning web 11a, a bundle of acrylic ultrafine fibers (average diameter 5 μm) is pressed,
A cloth-shaped non-woven fabric (thickness 150 μm) was used.
In addition, a non-woven fabric made of resinous ultrafine fibers such as nylon, polyester and rayon can be used.

In the present embodiment, as shown in FIG. 1, the degree of dirt (adhesion amount) on the surface of the transfer material carrying sheet 5f of the dielectric sheet is determined by each event in the image forming process (eg, during jamming).
Predict accordingly. Then, according to this amount of adhesion, the feed amount of the cleaning web 11a (the cleaning web 11 during one rotation of the transfer drum 5a during the cleaning operation)
The feed amount of a) is changed.

As shown in FIG. 1, the feed amount of the web 11a is 1 mm after the apparatus is started up (when the transfer drum is rotated in the warm-up state) and before or after the normal copying, and after the continuous copying. And the cleaning web 11a after the feedback sequence is moved.
The feeding amount of the cleaning web 11a is 2 mm, and the feeding amount of the cleaning web 11a is 5 mm at the time of jamming (transfer material clogging). The feeding means of the cleaning means 11 is activated by each signal of the sequence of the copying machine.

Here, the feedback sequence is
The density of the toner image formed on the photosensitive drum 1 is directly read by an optical sensor (not shown), and the developing bias is controlled.
This is a sequence for keeping the image density constant, and is a sequence for cleaning the dirt on the surface of the transfer material carrying sheet 5f made of a dielectric substance by the toner on the photosensitive drum 1 at the transfer position during the operation of this sequence. ..

[Example 2] Dielectric transfer material carrying sheet 5
It is also possible to directly detect the degree of dirt on the surface of f and determine the web feed amount according to the detection signal. In FIG. 2, the reflection type optical sensor 41 provided immediately after the transfer position of the transfer drum shown in FIG.
3 shows the relationship between the reflection optical density and the feed amount when the feed amount of is determined. That is, when the reflection optical density is 0.4, the feeding amount of the cleaning web 11a is 1 mm, when the reflection optical density is 0.4 to 1.2, the feeding amount of the cleaning web 11a is 2 mm, and the reflection optical density is 1.2 or more. Then, the feed amount of the cleaning web 11a is set to 5 mm. As a result, the transfer material carrying sheet 5f can be more reliably
Could be cleaned.

[Embodiment 3] The transfer material carrying sheet 5f by reversing the transfer electric field polarity in the transfer charger 5b during jamming.
After the toner on the surface is re-transferred onto the photosensitive drum 1 (especially at the time of jamming), the transfer material carrying sheet 5f is cleaned by the cleaning means 11 of the present invention, so that the feeding amount of the cleaning web 11a at the time of jamming is further improved. It can be reduced (Fig. 3). That is, when the transfer electric field polarity is not changed during the jam, the feeding amount of the cleaning web 11a is 5 mm.
It was necessary (Fig. 1), but 2 mm was sufficient.

In the embodiment, the transfer drum is used as a transfer material carrier, but the dielectric endless belt is passed through the transfer portion of one or more image forming stations to convey and guide the transfer material, and the endless belt is cleaned with a cleaning web. The same can be applied to the case.

[0025]

As described above, according to the present invention, the feeding amount of the cleaning web can be reduced and the cleaning means can be downsized.

[Brief description of drawings]

FIG. 1 is a flow sheet of an example of the present invention.

FIG. 2 is a diagrammatic view of another embodiment of the present invention.

FIG. 3 is a flow sheet of another embodiment of the present invention.

FIG. 4 is a vertical sectional view of an embodiment of an image forming apparatus to which the present invention is applied.

[Explanation of symbols]

 5 transfer device 5a transfer drum 5f transfer material carrying sheet 11 cleaning means 11a cleaning web 11b backup brush 41 optical sensor

Claims (1)

[Claims] 1. A transfer material carrier for holding an image carrier having a toner image, a transfer material for transferring the toner image, and conveying and guiding the transfer material to a transfer position of the image carrier, In an image forming apparatus provided with a cleaning means having a cleaning web in contact with the transfer material carrier and a feeding means for the cleaning web, the amount of deposits on the transfer material carrier is predicted or detected, and the amount of deposits is determined according to the amount of deposits. An image forming apparatus comprising: a means for changing a feeding amount of a cleaning web.