JP2003255808A - Image forming apparatus and cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of performing accurate position detection and density detection as long as the life of the main body of the image forming apparatus by periodically, reliably and appropriately cleaning a position detecting means and a density detecting means and of maintaining a satisfactory image forming state with a moderate image output by preventing an image failure such as registration deviation and a color balance failure, and to provide a cartridge. <P>SOLUTION: In this image forming apparatus 26 having an image carrier 9 and detecting means 22 and 23 for detecting an optical characteristic on the surface of the image carrier 9, the image carrier 9 forms the cartridge 24 that can be loaded and extracted in/from the image forming apparatus main body 26, and the cartridge 24 is provided with a cleaning member 25 for cleaning the detecting means 22 and 23 when the cartridge 24 is loaded and extracted. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a cartridge that is periodically replaced and forming an image on a recording medium (transfer material).

[0002]

2. Description of the Related Art Conventionally, as a color image forming apparatus,
Various methods such as electrophotographic method, thermal transfer method and ink jet method are known. Among them, the electrophotographic method is different from other methods in terms of image forming speed, image quality, quietness, etc. Is excellent at.

Among the image forming apparatuses adopting the electrophotographic method, there are various methods. For example, a multi-development method in which a color developer image (a toner image of a plurality of colors) is superposed on the surface of a photoconductor and then is collectively transferred to a transfer material as a recording medium to form an image, or a cycle of development and transfer is repeated. Multiple transfer method, once, developer image (toner image) of each color on the intermediate transfer body
There is an intermediate transfer method, etc., in which primary transfer is sequentially performed and then collectively transferred onto a transfer material. Of these, the intermediate transfer type has the advantages that there is no risk of color mixing and that various transfer materials of different quality and thickness can be used.

FIG. 12 shows an outline of a four-color full-color laser beam printer as an example of an intermediate transfer type image forming apparatus. As shown in FIG. 12, on the peripheral surface of the drum-shaped photosensitive member (photosensitive drum) 1 which is the first image bearing member, the charging unit 2 and the laser light are sequentially provided along the rotation direction (direction of arrow R1). An exposure device 3 for irradiating the photosensitive drum 1, a developing device 4'which is a developing means, a belt-shaped intermediate transfer member (intermediate transfer belt) 9 which is a second image carrier, and a photosensitive drum cleaner 16 are arranged. There is.

First, the surface of the photosensitive drum 1 is negatively charged by the charging means 2 to which a charging bias is applied from the power supply 15. Next, the charged photosensitive drum 1
An electrostatic latent image is formed on the surface by the exposure L of the exposure unit 3. The developing device 4 ′, which is a developing means, is a rotation provided on a rotary 4 in which developing devices 5, 6, 7, and 8 containing four color developers (toners) of yellow, magenta, cyan, and black are respectively rotated. It is a developing device. The developing device 5 mounted on the rotary 4 and containing the first color yellow toner causes toner to adhere to the electrostatic latent image portion on the photosensitive drum 1 to form a toner image.

The intermediate transfer belt 9 is supported by two supporting shafts (secondary transfer counter roller 12 and tension roller 14) and is driven in the direction of arrow R4 in the figure.
2 rotates in the direction of arrow R3, which is the forward direction of the rotation direction R1 of the photosensitive drum 1. Then, the primary transfer power supply 17 is applied to the primary transfer roller 10 that is rotated by the intermediate transfer belt 9.
When a positive primary transfer bias is applied from, the toner image on the photosensitive drum 1 is primarily transferred via the primary transfer nip portion N1. The primary transfer residual toner on the surface of the photosensitive drum 1 after the primary transfer is removed by a photosensitive drum cleaner 16 having an elastic blade.

The above-described series of image forming processes of charging, exposure, development, primary transfer, cleaning and charge removal are carried out by the second color magenta, third color cyan and fourth color black toners stored in the respective developing units 6, 7 and 8. Repeat for
Four color toner images are superposed on the intermediate transfer belt 9.

At this time, a position detection member (position detection mark) 21 having a reflectance different from that of the intermediate transfer belt 9 is provided in the non-image area on the intermediate transfer belt 9 serving as an image carrier for aligning the transfer position of the toner image. A position detecting unit (position detecting sensor) 22 provided on the main body of the image forming apparatus so as to face the intermediate transfer belt 9 and configured of a light emitting element and a light receiving element detects a position due to a difference in reflected light. Is being detected. The signal detected by the position detection sensor 22 based on the optical characteristics is sent to an engine controller (not shown) to control the image forming timing. By this position detection and control, the position (registration) of each toner image can be matched.

When the secondary transfer bias is applied by the secondary transfer roller 11 connected to the power source 18 rotating in the direction of arrow R4 in the figure, the secondary transfer nip portion N2 on the secondary transfer counter roller 12 is applied. Secondary transfer is collectively performed on the surface of the transfer material P. Transfer material P having an unfixed toner image of four colors on its surface
Is conveyed to a fixing device (not shown), the toner image on the surface is fixed, and the image formation is completed.

On the other hand, in adjusting the density of the output image, a toner image for density detection of a specific halftone pattern by area gradation is formed on the intermediate transfer belt 9, and the toner image is opposed to the main body of the image forming apparatus. Concentration detection means (concentration detection sensor) consisting of a light emitting element and a light receiving element
By measuring the reflected light amount of the density detecting toner image which is a halftone pattern on the intermediate transfer belt 9 at 23, the image forming conditions such as the developing bias potential for controlling the image forming density of the image to be formed can be determined. Done. This image forming density adjustment is performed when the power of the image forming apparatus is turned on and after printing a predetermined number of sheets, and the density is regularly controlled. Although the density detection may be performed on the photosensitive drum 1,
In this example, it is performed on the intermediate transfer belt 9.

When using the image forming apparatus described above, needless to say, maintenance such as replenishment of toner, processing of waste toner, replacement of the worn photosensitive drum 1 and the intermediate transfer belt 9 is required. In this example, the developing devices 5, 6, 7, 8
And a photosensitive drum 1, a photosensitive drum cleaner 16, a charger 2, an intermediate transfer belt 9, a primary transfer roller 10, a secondary transfer counter roller 12, a tension roller 14, and a waste toner container (not shown). The integrated unit type allows the user to easily attach / detach and replace the device body.

The above-mentioned unit is removable as a cartridge in the main body of the apparatus and includes the photosensitive drum 1 and the intermediate transfer member 9, so that the intermediate transfer belt / photosensitive drum cartridge 24
(Dotted line part).

The image forming apparatus main body is opposed to the intermediate transfer belt 9 of the intermediate transfer belt / photosensitive drum cartridge 24, and in the main body of the image forming apparatus, a light emitting element for detecting the optical characteristics of the intermediate transfer belt 9 which is an image carrier. Two sensors, a position detection sensor 22 and a density detection sensor 23, each of which includes a light-receiving element and a light-receiving element, are provided to reflect the light emitted by the light-emitting element to a toner image on the intermediate transfer belt 9 and reflect the light. The position (registration) of the image and the image forming density are detected by a method of measuring the amount of light with a light receiving element.

However, since the intermediate transfer belt 9 having the toner image superposed on the surface passes over the sensors 22 and 23, the toner is scattered from the intermediate transfer belt 9 or electrostatically attracted to the sensor. May adhere to the protective surface.

Therefore, when image output is repeated 10,000 times using the intermediate transfer belt / photosensitive drum cartridge 24, the toner covers the protective surfaces of the sensors 22 and 23 and reaches the intermediate transfer belt 9. 22, 23
The light emitted from the sensor and the light reflected from the intermediate transfer member 9 by the sensors 22 and 23 are prevented from being received, and the detection accuracy is reduced by about 40%. If the detection accuracy of the density detection sensor 23 or the position detection sensor 22 decreases by 50% or more,
Since accurate density detection and position detection cannot be performed, these sensors 22 and 23 need to be regularly cleaned.

In order to clean the position detecting sensor 22 and the density detecting sensor 23, in this example, as shown in FIG. 13, a cleaning brush 42 which moves so as to cover the sensors 22 and 23 is an image forming apparatus. It is installed in the main body.

When the upper lid 41 of the image forming apparatus main body 26 is opened and closed in the direction of the arrow A7 in the figure by a half-rotational movement, the position detecting sensor 22 and the density detecting sensor 23, which are installed side by side in this example, by a driving means (not shown). The cleaning brush 42 installed at a position where it can pass over both of them rotates around its tip portion 42a in the figure and interlocks in the direction of the arrow A8, and at that time, moves above the sensors 22, 23. Pass through
Perform cleaning. When the user replaces the intermediate transfer belt / photosensitive drum cartridge 24 or the developing devices 5, 6, 7, and 8, the upper lid is always opened and closed, so that the sensors 22 and 23 can be necessarily cleaned.

The cleaning brush 42 includes both sensors 22,
The portion in contact with 23 is in the shape of a brush made of nylon bristles having a wire diameter of 0.15 mm, and is configured to scrape off the adhered substances of the sensors 22 and 23.

[0019]

However, in cleaning the position detecting sensor 22 and the density detecting sensor 23 of the above-mentioned conventional example, the cleaning brush 42 is used for a long period of time until the life of the image forming apparatus main body. In some cases, the bristles of the brush may be broken or the toner may adhere to the brush, resulting in a decrease in cleaning efficiency.

Therefore, image output is repeated without proper cleaning of the sensors 22 and 23, and as shown in the above-mentioned conventional example, the detection accuracy of the sensors 22 and 23 deteriorates, and the registration becomes incorrect. The output image may be affected, such as the color balance being lost.

Therefore, an object of the present invention is to perform appropriate cleaning of the position detecting means and the density detecting means regularly and surely,
Accurate position detection and density detection can be performed over the life of the image forming apparatus main body, image defects such as misregistration and poor color balance can be prevented, and good image formation can be maintained with appropriate image output. An object is to provide an image forming apparatus and a cartridge.

[0022]

The above object can be achieved by an image forming apparatus and a cartridge according to the present invention. In summary, the first aspect of the present invention is an image forming apparatus having an image carrier and a detection unit for detecting the optical characteristic of the surface of the image carrier, wherein the image carrier is the main body of the image forming apparatus. A removable cartridge is configured, and the cartridge includes
There is provided an image forming apparatus characterized in that a cleaning member is provided for cleaning the detection means by mounting and demounting the cartridge.

According to one embodiment of the first aspect of the present invention, the detection means detects the optical characteristics of the detection developer image formed on the surface of the image carrier, and forms an image based on the detection result. The condition is controlled, and the image forming condition is the image forming density which is the density of the obtained image.

According to another embodiment of the first aspect of the present invention, the detection means detects the optical characteristic of the position detection member formed on the surface of the image carrier, and forms an image based on the detection result. Control timing.

According to another embodiment of the first aspect of the present invention, the image carrier is an intermediate transfer member onto which a developer image for secondary transfer onto a transfer material is primarily transferred, or is developed on the surface. It is a photoreceptor on which an agent image is formed.

A second aspect of the present invention is an image forming apparatus having a transfer material carrier that conveys a transfer material onto which a developer image is transferred, and a detection unit that detects optical characteristics of the surface of the transfer material carrier. The transfer material carrier constitutes a cartridge that can be attached to and detached from the main body of the image forming apparatus, and the cartridge is provided with a cleaning member that cleans the detection means by attaching and detaching the cartridge. An image forming apparatus is provided.

A third aspect of the present invention is detachably mountable to an image forming apparatus main body having a detecting means for detecting the optical characteristic of the surface of the image carrier, and is constituted by the image carrier and is detachably mounted to the image forming apparatus main body. Thus, the cartridge is provided with a cleaning member for cleaning the detection means.

According to an embodiment of the third aspect of the present invention, the image carrier is an intermediate transfer member on which a developer image for secondary transfer to a transfer material is primarily transferred, or a developer is formed on the surface. A photoconductor on which an image is formed.

The fourth aspect of the present invention is detachably mountable to an image forming apparatus having a detection means for detecting the optical characteristics of the surface of a transfer material carrier carrying a transfer material on which a developer image is transferred. A cartridge comprising a body and provided with a cleaning member for cleaning the detection means by attachment and detachment.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The image forming apparatus and cartridge according to the present invention will be described below in more detail with reference to the drawings.

Embodiment 1 FIGS. 1 and 2 are schematic diagrams according to Embodiment 1 of the present invention, in which an intermediate transfer belt / photosensitive drum cartridge 24 having a cleaning member 25 is inserted into a main body 26.

FIG. 1 shows an intermediate transfer belt / photosensitive drum cartridge 24 (hereinafter referred to as "cartridge 24").
Before mounting on the body 26, and FIG. 2 after mounting. Members having the same functions as those of the conventional example are indicated by the same reference numerals and the description thereof will be omitted.

In this embodiment, the cartridge 24 includes the photosensitive drum 1, the photosensitive drum cleaner 16, the charger 2, the intermediate transfer belt 9, the primary transfer roller 10, the secondary transfer counter roller 12, the tension roller 14, and the cartridge 24, as in the conventional example. It has a cartridge type configuration in which a waste toner container (not shown) is integrated. The structure of the cartridge 24 is similar to that shown in FIG. 12, and in FIGS. 1 and 2, members other than the photosensitive drum 1 and the intermediate transfer belt 9 are omitted.

By using the cartridge type, the user can easily attach and detach the main body 26, and the maintenance can be performed.

Position detection sensor 22 and density detection sensor 2
Reference numeral 3 denotes a detection unit which is composed of a light emitting element and a light receiving element and detects the optical characteristics of the surface of the image carrier, which is the intermediate transfer belt 9 in this case, and is provided on the main body 26 side. When the cartridge 23 is attached to the main body 26, the position detection window W is provided in the frame 24 'of the cartridge 24 so as to face the surface of the intermediate transfer belt 9 inside the frame 24'.
1 and the density detection window W2 face the positions of both sensors 22 and 23 so that the position and density can be detected.

Since the intermediate transfer belt 9 on which the toner image is superposed on the surface passes over the sensors 22 and 23, the toner is scattered from the intermediate transfer belt 9 and the sensors 22 and 23 are electrostatically attracted. May adhere to the protective surface of.

As described in the conventional example, when the image output is repeated 10,000 times using the cartridge 24, the toner covers the protective surfaces of the sensors 22 and 23 and reaches the intermediate transfer belt 9. The light emitted by each of the sensors 22 and 23 and the reflected light from the intermediate transfer member 9 are prevented from being received,
Each detection accuracy is reduced by about 40%. If the detection accuracy of the density detection sensor 23 decreases by 50% or more, accurate density control cannot be performed, the color balance is disturbed, and the amount of applied toner increases and characters scatter. Yes, the output image is affected.

Similarly, when the detection accuracy of the position detection sensor 22 is reduced by 50% or more, accurate position detection cannot be performed, the position (registration) cannot be matched, and in some cases, image output can be performed. It may disappear.

Therefore, in the cartridge 24 of this embodiment, the number of printable sheets is 8,000, and the position detection sensor 22
By installing a cleaning member 25 capable of cleaning the density detection sensor 23 and the density detection sensor 23 at the bottom of the cartridge 24, cleaning can be performed at the time of attachment / detachment.

The cleaning member 25 is in the shape of a brush, and is made of nylon as a material, and has a wire diameter of 0.15 mm and a wire length of 5 mm so as not to damage the protective surfaces of the position detection sensor 22 and the density detection sensor 23 by cleaning. did. Cartridge 24
The brush of the cleaning member 25 scrapes off the toner adhering to the protective surfaces of the position detection sensor 22 and the density detection sensor 23 by exchanging or removing.

The cleaning member 25 is installed on the outer surface of the frame 24 'of the cartridge 24 on the same plane X of the position detection window W1 and the density detection window W2. The surface X is directed toward the sensors 22 and 23, and the position of the cleaning member 25 is inserted in the direction A1 in which the cleaning member 25 is rubbed against the sensor first.

Position detection sensor 22 and density detection sensor 2
Detection accuracy of 3 is reduced by about 40% (Cartridge 2
4), the cleaning member 25 is attached to both sensors 22 and 2
While rubbing against the cartridge 3, the cartridge 24 in which the new cleaning member 25 is installed is inserted into the main body 26 in the direction of arrow A1 in FIG. 1, and the sensors 22 and 23 are automatically cleaned. When the installation of the cartridge 24 is completed by sliding the cleaning member 25 portion in the A1 direction, the position detection window W1 and the concentration detection window W2 provided on the same surface as the cleaning member 25 reach the positions facing the respective sensors 22 and 23. (Fig. 2).

Then, the cartridge 24 is installed in the apparatus, and at the same time, the sensors 22 and 23 are cleaned.
Since the cleaning brush 42 of the conventional example is provided in the apparatus main body 26, it cannot be replaced frequently, whereas the cleaning member 25 is
Since each cartridge 24 is provided, a new cleaning member 25 is always provided when the cartridge 24 is replaced.
As a result, each sensor 22 and 23 is cleaned, and each detection can be performed with 100% accuracy. Even when the cartridge 24 in which the new cleaning member 25 is installed is taken out from the image forming apparatus, the cleaning efficiency similar to that at the time of insertion can be obtained.

Further, the image forming apparatus main body 26 of this embodiment is
By replacing the cartridge 24 and the developing devices 5, 6, 7, and 8, it is possible to print up to 100,000 sheets.

FIG. 10 shows the configuration of the sensors 22 and 23 when the cartridge 24 is replaced and printing is performed up to the life of the image forming apparatus main body 26 every 8,000 sheets, which is the life of the cartridge 24. This is a transition of sensor detection accuracy. Up to 100,000 sheets, which is the life of the image forming apparatus body 26,
The sensor detection accuracy never fell below 50%.

With the configuration described above, the user replaces the cartridge including the intermediate transfer belt and the photosensitive drum at the end of the life of the cartridge, and at the time of replacement, appropriate cleaning of each sensor such as the position detection sensor and the density detection sensor is performed at the same time. Was performed regularly and reliably, and image defects and malfunctions could be prevented until the life of the main body.

Embodiment 2 FIG. 3, FIG. 4 and FIG. 5 are schematic views according to Embodiment 2 of the present invention, showing the attaching / detaching operation of the cartridge 24 in which the cleaning member 25 is installed. 3 is before mounting the cartridge 24 on the main body 26, and FIG. 4 is after mounting it. Also, FIG.
Shows that the cartridge 24 is taken out from the main body 26. Members having the same functions as those of the conventional example are indicated by the same reference numerals and the description thereof will be omitted.

Similar to the first embodiment, the cartridge 24 has the cleaning member 2 on the same plane X as the position detecting window W1 and the density detecting window W2.
5 is provided, and the apparatus main body 2 is operated by the operation shown in FIGS. 3 and 4.
6 and the cleaning member 25 at the same time as mounting the sensor 2
2 and 23 can be cleaned, and the user can easily attach and detach them from the main body 26 so that maintenance can be performed.

In this embodiment, in addition to the same structure as that of the first embodiment, when the cartridge 24 is removed from the main body 26, first, as shown in FIG.
Here, it is raised in the direction of arrow A2 in FIG. 5 and then lifted in the direction of arrow A3 in FIG. 5 with the axis of rotation B1 disposed in the vicinity where the photosensitive drum 1 is located as an axis. Cartridge 24
Since the cleaning member 25, which has been soiled by cleaning each sensor 22 or 23 at the time of mounting, can be removed from the main body 26 without touching each sensor 22 and 23, each sensor 22 and 23 is not contaminated when the cartridge 24 is removed. It is like this.

Further, since the cleaning member 25 is also replaced at the same time by replacing the cartridge 24, the new cleaning member 25 can always clean each sensor, and the cleaning efficiency in replacing the cartridge 24 is improved.

The graph of FIG. 11 shows a case where the cartridge 24 is replaced every 8 thousand sheets, which is the life of the cartridge 24, and printing is performed up to the life of the image forming apparatus main body 26 by the configuration of the second embodiment. This is a transition of sensor detection accuracy.

As in the case of the first embodiment, by simply replacing the cartridge by the user at the end of the life of the cartridge, proper cleaning of the detection means such as the position detection sensor and the density detection sensor can be performed regularly and reliably, and the life of the main body is reached. Up to the above, it is possible to prevent the image defect and the malfunction from occurring, and further, the detection means (sensor) is cleaned by attaching and detaching the cartridge in this manner, only when the cartridge is attached to the image forming apparatus main body. 100,000 or more sheets detection accuracy 100%
Was maintained, and the effect was further enhanced.

Embodiment 3 FIGS. 6 and 7 are schematic diagrams according to Embodiment 3 of the present invention. Members having the same functions as those in the conventional example and the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, the cartridge form is changed so that the intermediate transfer belt 9, the primary transfer roller 10, the secondary transfer counter roller 12, and the tension roller 14 are integrally formed, and the photosensitive drum 1. , The photosensitive drum cleaner 16 (not shown), and the photosensitive drum cartridge 30 in which the charger 2 is integrated, and the two cartridges 30 and 31 can be independently attached and detached from the main body, and can be replaced by the user according to their respective life periods. It is possible.

The density is detected by the photosensitive drum cartridge 30.
From the density detection window W3 of the cartridge frame 30 'in
By the concentration detection sensor 23 of the main body 26 facing it,
The configuration is performed on the photosensitive drum 1. Photosensitive drum 1
In the density detection performed above, the transfer step is not necessary, so the density detection time can be shortened.

The position is detected by the cartridge 24 of the first embodiment.
Similarly, from the position detection window W1 installed in the cartridge frame 31 'of the intermediate transfer belt cartridge 31, the position detection sensor 22 provided in a place different from the place where the density detection sensor 23 of the main body is provided is detected. To do.

Similar to the first embodiment, the photosensitive drum 1 carrying the toner image and the intermediate transfer belt 9 are connected to the sensors 22 and 2 respectively.
Since the image passes through 3 above, when the image output is repeated 10,000 times, the scattered toner covers each sensor protective surface, and each detection accuracy is reduced by about 40%.

The number of printable sheets of the photosensitive drum cartridge 30 of the present embodiment is 5,000, and by the end of this life, the detection accuracy of the density detection sensor 23 is reduced by about 25% due to the adhered toner. .

Therefore, in this embodiment, the cleaning member 29 is installed in the photosensitive drum cartridge 30 so that the density detection sensor 23 can be cleaned by mounting and dismounting the photosensitive drum cartridge 30. The density detection sensor 23 can be cleaned.

Frame 30 'of the photosensitive drum cartridge 30
Is a substantially roller shape along the peripheral surface of the photosensitive drum 1, and A
It is attached to the image forming apparatus by a half-rotation movement in five directions. The cleaning member 29 is provided upstream of the concentration detection window W3 in the rotation direction A5 of the frame body 30 '.

Like the cleaning member 25, the cleaning member 29 has a brush shape, and when the photosensitive drum cartridge 30 is replaced or removed, the brush of the cleaning member 29 scrapes off the toner adhering to the protective surface of the density detection sensor 23. Cleaning is completed.

The detection accuracy of the density detection sensor 23 is about 25%.
When the photosensitive drum cartridge 30 in which the new cleaning member 29 is installed is inserted into the main body 26 in the reduced state (lifetime of the photosensitive drum cartridge 30) in the direction of arrow A5 in FIG. 6, the upstream cleaning is performed. The member 29 is rubbed against the density detection sensor 23 first, and the density detection sensor 2
3 is automatically cleaned. When fully installed,
As shown in FIG. 7, the density detection window W downstream of the cleaning member 29.
3 comes to face the density detection sensor 23. Thus, the density detection sensor 23 is cleaned by the new cleaning member 29 every time the photosensitive drum cartridge 30 is replaced, so that the density detection can be performed with 100% accuracy.
Also, the new cleaning member 29 is the photosensitive drum cartridge 30.
Even when the sheet is taken out from the image forming apparatus, the same cleaning efficiency as that when the sheet is inserted can be obtained.

On the other hand, the intermediate transfer belt cartridge 31
The number of printable sheets is 8,000, and the cleaning member 25 is installed below the intermediate transfer belt cartridge 31 in the same state as the cartridge 24 of the first embodiment. By the operation similar to that of the first embodiment, the intermediate transfer belt cartridge 31 is replaced or detached, so that the cleaning member 25 wipes off the toner adhering to the protective surface of the position detection sensor 22 provided at the same position as that of the first embodiment. , Cleaning is completed.

The detection accuracy of the position detection sensor 22 is about 40%.
When the intermediate transfer belt cartridge 31 in which the new cleaning member 25 is installed is inserted into the main body 26 in the direction of arrow A4 in FIG. 6 in the reduced state (lifetime of the intermediate transfer belt cartridge 31), the position detection sensor 22 automatically After that, the position can be detected with 100% accuracy.
Further, even when the intermediate transfer belt cartridge 31 in which the new cleaning member 25 is installed is taken out from the image forming apparatus, the cleaning efficiency similar to that at the time of insertion can be obtained.

With the above structure, the photosensitive drum cartridge 30 and the intermediate transfer belt cartridge 31 are exchanged for each life, and printing is performed up to 100,000 sheets, which is the life of the main body 26. Similar to No. 1, the detection accuracy of each sensor did not fall below 50%.

Further, by providing the positions of the density detecting sensor 23 and the position detecting sensor 22 in different places, and
By using the photosensitive drum 1 as the image bearing member on which the toner image for density detection is formed, and by devising the method of taking out each cartridge as in the second embodiment, the photosensitive drum cartridge 30 and the intermediate transfer belt cartridge 31 are taken. Cleaning efficiency can be improved by changing the attaching and detaching directions of the.

With the configuration described above, the user simply replaces the photosensitive drum cartridge 30 and the intermediate transfer belt cartridge 31 at the end of their service life.
Appropriate cleaning of the density detection sensor 23 and the position detection sensor 22 can be performed regularly and surely, and it is possible to prevent the occurrence of image defects and malfunctions until the life of the main body 26.
In addition, since the cleaning member is provided for each of the plurality of cartridges, which have different attachment / detachment directions for each sensor, it is possible to improve the cleaning efficiency.

Embodiment 4 FIGS. 8 and 9 are schematic diagrams according to Embodiment 4 of the present invention. Members having the same functions as those in the conventional example and the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, the present invention is applied to an image forming apparatus using a transfer material carrier for adsorbing a transfer material by an in-line system having a plurality of photoconductors for each color.

FIG. 9 shows an outline of the image forming apparatus of this embodiment.

The photosensitive drum 1, the exposure device 3, the developing device 5, and the photosensitive drum cleaner 16 are unitized as one process cartridge, and the process cartridge 3 of each color of black, magenta, cyan, and yellow is formed.
3, 34, 35, 36 are arranged in series. The transfer material P is electrostatically adsorbed on the electrostatic adsorption conveyance belt 38 (transfer material carrier) that is wound around the drive roller 37 and the tension roller 14, and the process cartridges 33, 34,
35 and 36 are sequentially conveyed. The primary transfer roller 10 is provided on the transfer surface t facing the process cartridges 33 to 36.
Is provided for each of the process cartridges 33 to 36, and each color is sequentially transferred to the transfer material P mounted on the transfer surface t. The transfer material P carrying the unfixed toner images of four colors on the surface is conveyed to a fixing device (not shown), and the toner image on the surface is fixed, and the image formation is completed.

Electrostatic attraction conveyor belt 38, drive roller 3
7, tension roller 14 and four primary transfer rollers 1
0 is integrated as the conveyor belt cartridge 32, and the user himself / herself can easily detach it from the image forming apparatus main body 39 together with the process cartridges 33 to 36, so that the user can perform maintenance as shown in FIG. Has become.

The density detection sensor 23 is provided on the side of the main body 39, has a structure in which the conveyor belt cartridge 32 is mounted, and the density is detected from the density detection window W4. The density detection is performed by forming a toner image of a specific halftone pattern by area gradation, which is a density detection toner image, on the electrostatic attraction and conveyance belt 38, similarly to the intermediate transfer belt 9 of the first embodiment.

As in the first embodiment, since the electrostatic attraction conveyance belt 38 carrying the toner image passes over the sensor 23,
The toner scattered from the electrostatic attraction and conveyance belt 38 may adhere to the protective surface of the sensor 23. When the image output is repeated 10,000 times using the above-mentioned conveyor belt cartridge 32,
The toner covers the protective surface of the sensor 23, and the detection accuracy is reduced by about 40%.

The number of printable sheets of the conveyor belt cartridge 32 of this embodiment is 8,000, and the cleaning member 40 capable of cleaning the density detection sensor 23 is installed on the side of the frame 32 'of the conveyor belt cartridge 32. By doing so, the density detection sensor 23 can be cleaned before an image defect and a malfunction due to a decrease in the accuracy of the sensor 23 occur. The cleaning member 40 is installed on the same plane X as the density detection window W4 of the frame 32 ′, and is located upstream of the density detection window W4 in the installation direction on the main body 39. The surface X on which the density detection window W4 and the cleaning member 40 are formed is provided on the opposite side of the transfer portion t facing each photoconductor 1. Then, the concentration detection sensor 2 as a detection member is provided toward the main body 39 so as to face the surface X.
3 is provided. Then, the conveyor belt cartridge 32 includes the density detection sensor 23 and each process station 3
3 to 36 can be installed in parallel movement (FIG. 8), and at the same time when installed in the main body 39, the cleaning member 40 cleans the density sensor 23, and then the density detection window W4 faces the density detection sensor 23. Then, the attachment to the main body 39 is completed (FIG. 9).

Again, since the cleaning member 40 is installed on the conveyor belt cartridge 32, the density detecting sensor 23 is always cleaned by a new cleaning member every time the conveyor belt cartridge 32 is replaced.

Like the cleaning member 25, the cleaning member 40 has a brush shape, and the brush of the cleaning member 40 scrapes off the toner adhering to the protective surface of the density detection sensor 23 by exchanging or removing the transport belt cartridge 32. , Cleaning is completed.

The detection accuracy of the density detection sensor 23 is about 40%.
When the transport belt cartridge 32 in which a new cleaning member 40 is installed is inserted into the main body in the direction of arrow A6 in FIG. 8 in the reduced state (lifetime of the transport belt cartridge 32), the density detection sensor 23 is automatically cleaned. The density detection can be performed with 100% accuracy. Further, even when the transport belt cartridge 32 having the new cleaning member 40 installed is taken out from the image forming apparatus, the cleaning efficiency similar to that at the time of insertion can be obtained.

With the above configuration, the conveyor belt cartridge 32 is replaced every 8,000 sheets, which is the life of the conveyor belt cartridge 32, and printing is performed up to 100,000 sheets, which is the life of the main body 39. , Sensor detection accuracy is 5
It never fell below 0%.

Also, cleaning efficiency can be improved by separating the conveyance belt cartridge 32 in the same direction as in the second embodiment, such as separating the portion of the main body 39 where the sensor 22 is installed.

With the configuration described above, the user can simply replace the conveyor belt cartridge 32 at the end of the life of the conveyor belt cartridge 32, and the density detection sensor 23 can be properly cleaned regularly and reliably. Until the time, it was possible to prevent the occurrence of the image defect and malfunction.

In the above, the cleaning of the position detection sensor and the density detection sensor has been described as an example in the first to fourth embodiments, but in addition, information on the belt carrying the toner image, the photosensitive drum, etc. is detected. The same effect can be obtained by using the configuration of the present invention to clean the sensor. Further, the shape of the cleaning member is not limited to the above-mentioned shape, and if the cleaning can be properly performed without damaging the sensor and the sensor protection surface, the same action and effect can be obtained even if another cleaning member is installed.

The present invention also includes a medium on which a position detection mark for position detection and a half pattern for density detection are formed, such as a photosensitive drum, an intermediate transfer member, or a conveyor belt related to image formation. A cleaning provided on the outer frame of the cartridge at the same time as mounting and demounting the cartridge which is attachable to and detachable from the main body of the image forming apparatus, and which has a detection means for detecting the position and the density from the position detection mark and the half pattern for density detection This is a configuration for cleaning the detection means by a member, and the configuration of the cartridge and the configuration of the detection means are not limited to this.

[0084]

As described above, according to the present invention, an image carrier and a detecting means for detecting the optical characteristics of the surface of the image carrier,
In the image forming apparatus having the image forming apparatus, the image carrier constitutes a cartridge that can be attached to and detached from the image forming apparatus main body, and the cartridge is provided with a cleaning member that cleans the detection unit by attaching and detaching the cartridge. And is detachably attached to the image forming apparatus main body having a detection unit that detects the optical characteristics of the surface of the image carrier, and is composed of the image carrier.
Since the cartridge is provided with a cleaning member that cleans the detecting means by being attached to and detached from the image forming apparatus main body, the position detecting sensor and A cleaning member for the density detection sensor is provided, and by mounting or removing the cartridge, proper cleaning of the detection means can be performed regularly and surely, and image defects and malfunctions caused by defective cleaning can be prevented.

[Brief description of drawings]

FIG. 1 is an explanatory view showing how a cartridge according to the present invention is attached to and detached from a main body.

FIG. 2 is an explanatory view showing how the cartridge according to the present invention is attached to and detached from a main body.

FIG. 3 is an explanatory diagram showing a state of attachment / detachment to / from a main body according to another example of the cartridge according to the present invention.

FIG. 4 is an explanatory view showing how a cartridge according to another embodiment of the present invention is attached to and detached from a main body.

FIG. 5 is an explanatory view showing a state of attachment / detachment to / from a main body according to another example of the cartridge according to the present invention.

FIG. 6 is an explanatory view showing a state of attachment / detachment to / from a main body according to another example of the cartridge according to the present invention.

FIG. 7 is an explanatory diagram showing a state of attachment / detachment to / from a main body according to another example of the cartridge according to the present invention.

FIG. 8 is an explanatory view showing a state of attachment / detachment to / from a main body according to another example of the cartridge according to the present invention.

FIG. 9 is an explanatory diagram showing a state of attachment / detachment to / from a main body according to another example of the cartridge according to the present invention.

FIG. 10 is a graph showing the relationship between the accuracy of the detection unit and the number of printed sheets in an example of the image forming apparatus according to the present invention.

FIG. 11 is a graph showing the relationship between the accuracy of the detection unit and the number of printed sheets in another example of the image forming apparatus according to the present invention.

FIG. 12 is a schematic configuration diagram of a conventional image forming apparatus.

FIG. 13 is an explanatory diagram showing an example of a detection unit cleaning member of a conventional image forming apparatus.

[Explanation of symbols]

1 Photosensitive Drum (Photosensitive Body) 9 Intermediate Transfer Belt (Intermediate Transfer Body) 22 Position Detection Sensor (Detection Unit) 23 Density Detection Sensor (Detection Unit) 24, 30, 31, 32 Cartridge 25, 29, 40 Cleaning Member 26 Image Formation Device main body 38 Conveyor belt (transfer material carrier) 42 Conventional cleaning member

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tatsuya Kobayashi             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Takushi Shibuya             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Dai Shimura             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Satoshi Saito             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H027 DA09 DA10 DA21 DA22 DE02                       DE07 DE10 EA05 EA18 EB04                       EC03 EC06 ED02 ED24 ED30                 2H071 BA04 BA13 BA14 BA27 BA35                       DA06 DA08 DA09 DA13 DA15                       DA23 DA32                 2H077 BA09 DA02 DA31 DA47 DA63                       DB00 DB08 GA03 GA13                 2H200 FA02 FA04 FA08 GA23 GA34                       GA44 GA47 GB12 HA02 HA28                       HB12 HB22 JA02 JC03 JC19                       JC20 LA38 PA10 PB15 PB18                       PB39

Claims (25)

[Claims] 1. An image forming apparatus having an image carrier and a detection unit for detecting an optical characteristic of the surface of the image carrier, wherein the image carrier constitutes a cartridge detachable from the main body of the image forming apparatus. The image forming apparatus is characterized in that the cartridge is provided with a cleaning member for cleaning the detecting means by mounting and demounting the cartridge. 2. The image forming apparatus according to claim 1, wherein the cleaning of the detection unit by attaching and detaching the cartridge is performed only when the cartridge is attached to the main body of the image forming apparatus. 3. The detecting means detects the optical characteristics of the detecting developer image formed on the surface of the image carrier, and controls the image forming condition based on the detection result. The image forming apparatus according to item 1 or 2. 4. The image forming apparatus according to claim 3, wherein the image forming condition is a condition for controlling an image forming density which is a density of an obtained image. 5. The detection means detects the optical characteristics of a position detection member formed on the surface of the image carrier, and controls the image formation timing based on the detection result. 1 or 2 of the image forming apparatus. 6. The image carrier according to claim 1, wherein the image carrier is an intermediate transfer member on which a developer image for secondary transfer onto a transfer material is primarily transferred. Image forming device. 7. The image forming apparatus according to claim 1, wherein the image carrier is a photoconductor on which a developer image is formed. 8. The cartridge is a process cartridge in which a photoreceptor on which a developer image is formed and an intermediate transfer body on which the developer image on the photoreceptor is electrostatically transferred are integrated. The image forming apparatus according to any one of claims 1 to 7, wherein: 9. The cartridge according to claim 1, wherein the cartridge has an intermediate transfer member on which a developer image on the photosensitive member is electrostatically transferred. Image forming apparatus. 10. The image forming apparatus according to claim 1, wherein the cartridge has a photoconductor on the surface of which a developer image is formed. 11. The cartridge according to claim 8, further comprising a charging unit and / or a cleaning unit and / or a developing unit that act on the image carrier.
Alternatively, 10 image forming apparatuses. 12. An image forming apparatus comprising: a transfer material carrier that conveys a transfer material onto which a developer image is transferred; and a detection unit that detects optical characteristics of the surface of the transfer material carrier. The body forms a cartridge that is attachable to and detachable from the main body of the image forming apparatus, and the cartridge is provided with a cleaning member that cleans the detection unit by attaching and detaching the cartridge. 13. The cleaning of the detection means by mounting and detaching the cartridge is performed only when the cartridge is mounted on the main body of the image forming apparatus.
2 image forming apparatus. 14. The detection means detects the optical characteristics of the detection developer image formed on the surface of the transfer material carrier, and controls the image forming condition based on the detection result. The image forming apparatus according to claim 12 or 13. 15. The image forming apparatus according to claim 14, wherein the image forming condition is a condition for controlling an image forming density of the developer image formed on the transfer material. 16. An image forming apparatus main body having a detection means for detecting the optical characteristics of the surface of the image carrier, the image forming apparatus main body being composed of the image carrier and being attached to or detached from the image forming apparatus main body to detect the image. A cartridge provided with a cleaning member for cleaning the means. 17. The cartridge according to claim 16, wherein the cleaning of the detection unit by the cleaning member is performed only when the detection unit is mounted on the main body of the image forming apparatus. 18. The cartridge according to claim 16, wherein the image bearing member is an intermediate transfer member to which a developer image for secondary transfer onto a transfer material is primarily transferred. 19. The cartridge according to claim 16, wherein the image carrier is a photoconductor on which a developer image is formed. 20. A photoreceptor on which a developer image is formed on the surface and an intermediate transfer body on which the developer image on the photoreceptor is electrostatically transferred are integrated. Claim 16-
19. The cartridge according to any one of item 19. 21. An intermediate transfer member, on which a developer image on the photosensitive member is electrostatically transferred.
The cartridge according to any one of 6 to 19. 22. The cartridge according to claim 16, further comprising a photoconductor on the surface of which a developer image is formed. 23. The cartridge according to claim 20, further comprising a charging unit and / or a cleaning unit and / or a developing unit that act on the image bearing member. 24. An image forming apparatus having a detection means for detecting the optical characteristics of the surface of a transfer material carrier that conveys a transfer material on which a developer image is transferred, and the image forming apparatus comprises the transfer material carrier. A cartridge characterized in that a cleaning member is provided for cleaning the detection means by attachment and detachment. 25. The cartridge according to claim 24, wherein the cleaning of the detection unit by the cleaning member is performed only when the detection unit is mounted on the main body of the image forming apparatus.