JPS62127767A - Color image forming device - Google Patents

Abstract

PURPOSE:To simplify the structure of a color image forming device and, at the same time, to obtain a stable cleaning effect with the device, by providing at least one cleaning member which is always separated from and never contacts with the image forming device. CONSTITUTION:A cleaning roller 49 is pressed against the peripheral surface of a photosensitive drum 40 while rotating clockwise when a blade 47 is pressure-contacted and the pressure-contacted state of the blade 47 is released. Moreover, it is arranged that a toner receiving roller 48 is formed of an electrostatically chargeable metallic roller and can be rotated counterclockwise and a prescribed impressed voltage can be applied across the roller 48 at a position where an extremely slight interval can be maintained between the peripheral surface of the drum 40 and roller 48. Therefore, when the blade 47 is pressed against the drum 40 by the action of a blade holder 47a before the leading edge of a transferred toner image reaches the blade 47 and the toner remaining on the surface of the drum 40 starts to drop, the toner receiving roller 48 which is electrostatically charged in the polarity that attracts the dropping toner by the impressed voltage attracts the toner and carries the toner counterclockwise. Then the toner carried in the counterclockwise direction is scraped down by a scraper 48a and sent to a toner carrying path 46b.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color image forming apparatus with improved cleaning means.

[Conventional technology]

In an image forming apparatus, after the photosensitive drum, which is the image forming body, has finished transferring the toner image formed on its circumferential surface to recording paper, the remaining toner is removed by a cleaning device during a continuous rotation cycle. After cleaning, it is charged again and the next image forming cycle begins.

The above-mentioned cleaning device generally uses a blade cleaning method which has a simple structure and has a high cleaning effect.As is well known, in the blade cleaning method, the edge of the blade member that presses against the circumferential surface of the photoreceptor drum cleans the circumferential surface of the photoreceptor drum. Since this type of device forcibly peels off the toner adhering to the surface, the peeled toner becomes powder or lumps and falls along the circumference of the photoreceptor drum, causing a gap between the cleaning device and the case. There are many problems such as falling and scattering into the main body of the forming apparatus and staining the recording paper and the like.

For this reason, in a cleaning device using a blade cleaning method, a toner receiver that contacts the photoreceptor drum is provided below the blade member, and the toner receiver inside the device is prevented from leaking to the outside of the cleaning device. The applicant has proposed a structure that allows for direct conveyance.

The toner receiver may be a simple plate-shaped Mylar blade as shown in Figure 5 (al) or a conveying roller that rotates following the rotation of the photoreceptor drum as shown in Figure (bl). Furthermore, in a cleaning device that uses a cleaning brush instead of a blade member, various members such as those shown in FIG.

[Problem that the invention seeks to solve]

However, the toner receivers described above are all supported so as to come into pressure contact with the circumferential surface of the photosensitive drum for cleaning purposes.

On the other hand, in a color image forming apparatus, a color toner image is formed by multiple rotations of a photoreceptor drum, so it is necessary to avoid a cleaning action on an unfinished toner image. The above-mentioned toner receiver as well as the response blade member are required to have a function of retracting the member away from the circumferential surface of the photoreceptor drum.

As a result, not only does the mechanism of the cleaning device become complicated, but also the toner receiver receives the toner separated from between the case of the cleaning device and the photoreceptor drum immediately after the members are separated and retracted. Moreover, due to the pressure contact and separation of the members, the toner receiver may be subject to more fluctuations in load relative to the rotation of the photoreceptor drum, which may cause uneven rotational speed and distortion of the toner image. However, there were many drawbacks as a cleaning member for use in color image forming apparatuses.

The present invention solves this problem and improves it. As a result, there is no need to press or separate the photoreceptor drum, so the structure is extremely simple, and a stable cleaning effect can be achieved without adding load to the rotation of the photoreceptor drum. The object of the present invention is to provide a color image forming apparatus equipped with a cleaning member that can be cleaned.

[Means for solving problems]

The above object includes a step of forming a latent image and developing a plurality of times on the image forming member to form a color toner image on the image forming member, a step of transferring and fixing the color toner image to a transfer member, and a step of transferring the color toner image to the transfer member and fixing the color toner image. a cleaning step of removing residual toner on the image forming body after the transfer by a cleaning means consisting of one or more cleaning members; when the color toner image is formed on the image forming body, the cleaning means A color image forming apparatus in which an unfinished color image passes through a position opposite to the color image forming apparatus, wherein at least one cleaning member of the cleaning means is not always in contact with the image forming body. Ru.

〔Example〕

An embodiment of the present invention is shown in FIGS. 1 to 4.

First, the general functions of the color image forming apparatus of the present invention will be explained with reference to FIG.

In FIG. 3, A is a reading unit, B is a writing unit, C is an image forming section, and D is a paper feeding section.

In the reading unit A, 1 is a platen glass, and a document 2 is placed on this platen glass 1. Manuscript 2
are illuminated by fluorescent lamps 5 and 6 mounted on a carriage 4 that moves entirely on a slide rail 3. The movable mirror unit 8 is provided with mirrors 9 and 9', which move on the slide rail 3, and in combination with the first mirror 7 provided on the carriage 4 read the optical image of the document 2 on the platen glass 1 with the lens. Derived to unit 20.

The carriage 4 and the movable mirror unit 8 are driven by a stepper motor 10 via a wire 15.
11, 12, 13, 14 KJ: are driven in the same direction at speeds of v and ]/2v, respectively. Standard white plates 16 and 17 are provided on the back side of both ends of the platen glass 1.
is provided, and is configured so that a standard white signal can be obtained before the document reading scan starts and/or after the scan ends.

The lens reading unit 20 has a lens of 21.7" lJ sum, a first reading board 24, a red channel (hereinafter referred to as R-ah) CCD 25, and a second reading board 2.
6. Cyan channel (hereinafter referred to as C-ch) CCD
It was stolen from 27. The original optical image transmitted by the first mirror 7, mirror 9, and mirror 9' is focused by a lens 21, and separated into a R-ah image and a C-ah image by a guichroic mirror provided in a prism 22. , R-ch CCD 2 provided on the first reading board 24
5 and C-ch C provided on the second reading board 26
Each of the light receiving surfaces of the CD 27 is imaged.

As the fluorescent lamps 5 and 6, commercially available warm white fluorescent lamps are used to prevent emphasis or attenuation of specific colors based on the light source when reading color documents, and 4Q fluorescent lamps are used to prevent flickering.
It is lit by a KHz high frequency power source and is kept warm by a heater using a POSISTOR to maintain a constant temperature of the tube wall or to promote warm-up.

Said R-ch CCD 25 and C-ah CCD 2
The image signal output from 7 is subjected to signal processing in the signal processing section. In the signal processing section, a color signal separated according to the toner color, which will be described later, is outputted and inputted to the writing unit I-B.

In writing unit B, a laser beam generated by a semiconductor laser is rotated and scanned by a polygon mirror 32 rotated by a drive motor 3o, passes through an Fθ lens 36, is completely bent by a reflecting mirror 37, and is directed onto the surface of a photoreceptor drum 40. It is projected and forms a bright line.

When scanning begins, the beam is detected by the index sensor and modulation of the beam by the first color signal begins. The modulated beam scans the photosensitive drum 40, which has been uniformly charged in advance by a charger 41. A latent image corresponding to the first color is formed on the drum surface by the main scanning by the laser beam and the sub-scanning by the rotation of the photosensitive drum 40. It is developed to form a toner image on the drum surface. The obtained toner image passes under the cleaning device 46, which is separated from the photosensitive drum surface, while being held on the drum surface, and enters the next copy cycle. The photosensitive drum 40 is charged with a charger, and then the second color signal output from the signal processing section is transferred to the writing unit B.
In the same manner as in the case of the first color signal, writing is performed on the drum surface to form a latent image. The latent image is produced by a developer 4 loaded with toner of a second color, for example blue.
4. This blue toner image is formed over the already formed red toner image.

A developing device 45 has black toner, and forms a black toner image on the drum surface based on a control signal generated by a signal processing section. These developing devices 43 and 44.

AC and DC biases are applied to the sleeve 45 to perform jumping development with two-component toner, and development is performed without contacting the grounded photosensitive drum 40.

The superimposed image of the toner image based on the first color signal, the toner image based on the second color signal, and the toner image developed using the black toner image developed in this way is transferred to the paper feeding section by the transfer pole 50. The image is transferred onto a recording paper 61, which is a transfer body, which is fed by a feeding belt 62 and a feeding roller 63. The recording paper 61 on which the toner image has been transferred is separated from the photoreceptor by a separation pole 51, and further conveyed to a fixing device 52 where it is fixed and a color note copy is obtained.

After the transfer has been completed, a cleaning device 46 equipped with a cleaning means according to the present invention shown in FIG. 1 acts on the photosensitive drum 40 to remove unnecessary toner remaining on the circumferential surface. There is.

A cleaning roller 49 and a blade 4 are used as cleaning means in the cleaning device 46 from the downstream direction in the rotational direction of the photosensitive drum 40 (indicated by the arrow ")".
7. The toner receiver is housed in a cleaning case 46a with each cleaning member of the roller 48 facing the circumferential surface of the photosensitive drum 40.

The blade 47a is made of a plate-like urethane rubber and is urged clockwise by the blade holder 47a to press against the circumferential surface of the photoreceptor drum 40, and the cleaning roller 49 is made of urethane rubber. The photoreceptor drum 40 is made of abrasive foamed urethane resin and rotates clockwise only for a predetermined period of time by the action of the sliding device 19a when the blade 17 is brought into contact with and released from the contact.
It is configured to press against the peripheral surface of.

Furthermore, in the present invention, the toner receiver is formed of a metal roller that can charge the entire roller 48, and then the photoreceptor drum 4 is formed as a metal roller.
The structure is such that counterclockwise rotation and a predetermined applied voltage can be applied at a position where a small gap is maintained with respect to the circumferential surface of the magnet.

Therefore, regarding the cleaning process using each of the cleaning members described above, before the leading edge of the transferred toner image reaches the blade 47, the blade 47 is brought into pressure contact with the blade 47 by the action of the blade holder 47H, and the residual toner is peeled off. When the toner falls, the toner receiver is charged with a polarity that attracts the toner by the applied voltage, and the roller 48 attracts the toner that has fallen along its circumferential surface and conveys it counterclockwise, and the scraper 48a picks up the toner. The toner can be scraped off and sent to the toner conveyance path 16b.

Furthermore, when the cleaning action by the pressure contact of the blade 47 is started and when the pressure contact is released after the cleaning action is finished, the rotation of the cleaning roller and the pressure contact act between the circumferential surface of the drum 40 and the blade 47. The small amount of toner left behind is removed to thoroughly clean the circumferential surface of the photosensitive drum 40 in preparation for the next exposure.

As described above, in the present invention, the toner receiver serves as at least one cleaning member of the above-mentioned cleaning means, and the roller 48 is always connected to the image forming member, that is, the photosensitive drum 4.
This makes it possible to collect the toner removed while being separated from the circumferential surface of the toner.

According to experiments, when the gap between the roller 48 and the circumferential surface of the photoreceptor drum 40 was set to 3.2 mm, and a voltage of +500 V was applied at 120 rotations per minute, the toner receiver could not transport toner. It has been confirmed that the cleaning members work very smoothly and are efficiently collected by the scraper 483 formed by a mylar blade. Figure 2 shows a second embodiment related to the present invention, and is the only cleaning member that can replace the above-mentioned cleaning members. As a cleaning member, a charging electrode 70 made of a wire stretched across a predetermined gap from the circumferential surface of the photosensitive drum 40 is arranged, and the charging electrode 70 is charged with a polarity opposite to that of the toner. An applied voltage is applied to suck the toner on the circumferential surface of the drum 40, and the toner is collected by the suction force of the powerful sirocco fan 82 through the suction duct 81 of the suction device 80 opened in the cleaning case 146a, and the toner is discharged into the discharge duct. 83
In this example, the charging electrode 70, which is a cleaning member, is always kept at a position separated from the circumferential surface of the drum 40.

As the voltage applied to the charging electrode 70, an alternating current bias voltage is applied, or an alternating current bias voltage is applied after giving the polarity opposite to that of the toner.
It is also possible to perform more effective cleaning by increasing the toner suction effect.If the cleaning effect is insufficient in the embodiment of body temperature 2, other cleaning members may be installed downstream and/or upstream of the charging electrode 70. It doesn't matter if it works. Examples include airflow from blades, fur brushes, and roller power suction (not shown).

The sequence of color image formation in the color image forming apparatus of the present invention, which is equipped with such a cleaning means, will be explained using the time chart shown in FIG. During the first rotation, the photosensitive drum 40 starts image exposure using the first color signal, and after undergoing development process (2) delayed by time X, it enters the second rotation and starts image exposure using the second color signal. The color toner image is constructed by undergoing the processing of development (2) which is delayed by the time y from the start, and further undergoes the processing of image exposure by the black signal at the third rotation and the processing of development (2) which is delayed by the time 2. .

Here, the time x*Yhz is the time required for a certain position of the main photosensitive drum 40 (in the figure, the leading edge of the image) to reach the position where each development process is performed from the image exposure position, or the time within that time. m is the time required from the image exposure position to reach the transfer point 50, or the time within that time;
n is the time required to reach the cleaning device 46 from the image exposure position or the time less than that. In addition, l is the time required for the entire image surface of the document to pass all fixed points such as image exposure or development processing positions, and the actions of image exposure, development processing, transfer, cleaning, etc. It is designed to operate for a period of time with some margin before and after l.

That is, in the case of the first embodiment described above, the blade 47 is operated for a time including a slight margin before and after the time l, but the cleaning roller 49 is operated for a time before and after the time 1.
The toner receiver may be operated for about 1 second from the start of operation and from the end of cleaning the entire image surface, respectively, and the roller 48 of the toner receiver may rotate at exactly the same timing as the blade 47. This has the advantage that there is no need to control the timing of applying the stain pressure.

On the other hand, in the second embodiment, both the charging of the charging electrode 70 and the action of the suction device 80 are performed for a time including a slight margin before and after the time 1, so that residual toner is effectively removed over the entire image surface. It is now possible to reliably remove the

〔Effect of the invention〕

As is clear from the above description, the cleaning means of the color image forming apparatus of the present invention includes at least one cleaning member that is always separated from the image forming body and never comes into contact with it. As a result, the structure of the cleaning device is extremely simple, and the efficiency of recovering the removed toner is improved.At the same time, there is no resistance due to load to the rotational operation of the image forming body. As a result, a color image forming apparatus capable of producing accurate copies with good image quality has been provided.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of a cleaning device included in the color image forming apparatus of the present invention. 3 and 4 are configuration diagrams of the image forming apparatus and a time chart of its operation, and FIG. 5 is a diagram of essential parts of each conventional cleaning means. 40...Photosensitive drum 46,146...Cleaning device 47...Blade 48...Toner receiver is roller 48a...Scraper 49...Cleaning roller 70...Charging electrode 80...Suction Apparatus 82 -- Scirocco Fan Applicant Roku Konishi Photo Industry Co., Ltd. Figure 1 146 Gree-Schiff 1 (1

Claims (1)

[Claims] forming a color toner image on the image forming body by performing latent image formation and development multiple times on the image forming body; transferring and fixing the color toner image onto the transfer body; and completing the transfer. a cleaning step of removing residual toner on the image forming body by a cleaning means comprising one or more cleaning members, and a position facing the cleaning means when the color toner image is formed on the image forming body; A color image forming apparatus through which an unfinished color toner image passes through, wherein at least one cleaning member of the cleaning means is not always in contact with the image forming body.