JPH08248734A - Image forming device - Google Patents

Abstract

PURPOSE: To increase the number of times that an image carrier is used by allowing a process unit comprising the image carrier and an electrifier to be replaced, and allowing the electrifier to be replaced with a new one in the process unit. CONSTITUTION: The process unit 118 integrates the photoconductive drum 101, the electrifier 102, a cleaner 117, and an opening/closing cover 118A which freely turns by means of a shaft 118B. The process unit 118 is taken out of the image forming device 100, the cover 118A is opened with a handle 118c used for opening/closing it, and the electrifier 102 is taken out of the process unit 118. Then, to replace this a new electrifier 102 is loaded. Or the process unit 118 is exposed by opening a sheet ejection tray 100A upward round a shaft 100B. Then, by opening the cover 118A of the process unit 118, the electrifier 120 can be taken out.

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 (electrophotographic apparatus) such as a copying machine or a laser printer, and more particularly to an image forming apparatus having an image carrier and a charging unit and a replaceable process unit. In particular, it relates to replacement of charging means.

[0002]

2. Description of the Related Art In the image forming apparatus as described above, a means for forming an electrostatic latent image on an image bearing member and forming an image by a developing device generally uses, for example, a photosensitive means by a charging means (hereinafter referred to as a charger). An electric charge is applied to the surface of the image carrier composed of a body, and the charged image carrier surface is exposed with an original image exposed by an exposure lamp or a laser beam or the like controlled by input of an image signal, After the electrostatic latent image is formed, it is developed with toner of the developing device to form a visible image. When a mono-black image is formed on the surface of the image carrier in the image forming apparatus as described above, first, an electric charge is applied by one charger, and the toner is exposed by the above-mentioned exposure method and developed with toner. The image carrier is formed of a rotating cylindrical drum, and after being sequentially charged, exposed, and developed, the image formed on the surface of the image carrier is immediately transferred to a recording paper and cleaned by a cleaning unit.

Therefore, when the charge is applied to the surface of the image bearing member by the charger, the toner image does not exist on the surface of the image bearing member, and the toner image is not attracted to the charger to cause stains. It can be used for a very long time. Even if the toner adheres to the charging discharge electrode, it can be reused by cleaning. In addition, as described above, a charge is first applied to the surface of the image bearing member by one charger, and development is performed in order of yellow (Y), magenta (M), cyan (C), and black (BK) in order to color the image. In the case of a color image forming method for forming an image, first, a charge is further applied to an image formed by a single color toner, and then exposure and development are repeated to form a full color image. The method of forming is done.

In the above-mentioned image forming apparatus, the image bearing member formed of the photosensitive member needs to be replaced due to deterioration of sensitivity after a certain number of recorded sheets (about 80,000 sheets). The image carrier is exchanged for each unit. In this case, the cleaning device for cleaning the image carrier and the charging device are almost replaced because the color image formation is frequently used, and the cleaning device and the charging device are integrated together with the image carrier. It can be replaced at the same time by configuring it as a process unit and replacing the process unit.

[0005]

As described above, the process unit in which the image carrier, the charger and the cleaning device are integrated is particularly applicable to the image carrier formed by the cylindrical drum as described above. On the other hand, the charger and the cleaning device are
It can be accurately fixed to a predetermined set position and is easy to manufacture. As described above, by purchasing and replacing only the process unit, it is possible to form an image on a new image carrier.

However, the recent image carrier has improved durability so that about 80,000 images can be formed even when forming a full-color image. On the other hand, as described above, the charging device performs the charging operation every time the images of yellow (Y), magenta (M), cyan (C), and black (BK) are formed in sequence, but especially magenta (M). , Cyan (C), and black (BK) color toner images are superposed, a charging action is performed on each color toner, and thus scattered toner is adsorbed and a part of toner is further developed from the developed color toner image. Is adsorbed and adheres to the tip of the band electrode in the charger. In particular, the acicular electrode formed in the shape of a needle increases the amount of toner attached to the tip, does not separate naturally, and is extremely difficult to clean because it is fixed to the process unit.
As described above, since the charger gives electric charges by the discharging action of the strip electrodes, an increase in the amount of toner adhered sharply lowers the discharge efficiency, so that a predetermined amount of electric charges is given to the surface of the image carrier. It is not possible to do so and the image quality is degraded. Therefore, before the charging efficiency of the charger is lowered, the process unit is to be replaced together with the image carrier. In this case,
The number of sheets in which the charging efficiency is reduced is much shorter than the number of the image carriers used (about 50,000 sheets), and even if the image carriers are usable for a considerable period of time, a process incorporating the image carriers and the charger We are replacing the unit.

As described above, the image bearing member, that is, the photosensitive member, can be used for a number of times to form an image, and can be used for a long period of time. The formed charger cannot prevent the adhesion of the toner,
Must be replaced in a short period of time. Therefore, a process unit in which an image carrier and a charger are integrated has a drawback that it must be replaced immediately after the period of use of the charger has expired.

The present invention was particularly conceived to remedy the aforementioned drawbacks. That is, at least an image carrier and a process unit having a charger are provided in the image forming apparatus in a replaceable manner, and the charger is replaceable by the process unit to extend the number of times the image carrier is used. The purpose is to always obtain a good image.

[0009]

To achieve the above object, the present invention provides an image forming apparatus according to claim 1, which comprises an image carrier and a process unit including one or more charging means. Means are provided interchangeably with the process unit. 3. The display unit according to claim 2, wherein the number of times the charging unit is set to be used is set shorter than the number of times the image carrier is set to be used, and the charging unit indicates that the process unit is to be replaced.
Or, it has a control means for stopping the image forming apparatus. 4. The charging unit according to claim 3, wherein the charging unit is replaceable with the process unit in a state where the process unit is attached to the image forming apparatus. 5. The charging device according to claim 4, wherein the charging unit causes the image forming apparatus to set the number of times of use set when forming a single color image to be different from the number of times of use set when forming a color image, and by setting the number of uses, Must be set to change the replacement time of. 6. The charging device according to claim 5, wherein the charging means is set at the same time as the image carrier replacement time. 7. An image forming apparatus having an image carrier and a charging means according to claim 6, wherein a counting means for reading the number of times of use of the charging means provided in an image forming process unit, and a predetermined number of times by the counting means. When the use of is counted,
And a display device for displaying the replacement of the charging means. 8. An image forming apparatus having an image carrier and a charging unit according to claim 7, wherein when the charger is replaced with respect to the image forming apparatus, the replacement is performed prior to the image formation by the image carrier. And having an initial setting means for setting that the number of times the charger has been used is the initial use. 9. An image forming apparatus having an image carrier and a charging means according to claim 8, wherein the image forming apparatus and a detecting means for detecting an energization state of the charging means, and an energization detected by the detecting means. Display means for displaying the status and / or control means for stopping the image forming apparatus are provided. 10. The detecting means for detecting the charged state of the image carrier by energizing the charging means, and the display means and / or the image forming apparatus for displaying the charged state detected by the detecting means are stopped. It is achieved by providing a control means for controlling.

[0010]

FIG. 1 is a sectional view showing a schematic structure of an image forming apparatus 100 which is an embodiment of the present invention, for example, a color laser printer. An outline of the configuration and a series of operations will be described based on the drawings.

After the photosensitive drum 101 as an image bearing member having an OPC photosensitive layer coated on its surface is driven and rotated in the direction of the arrow, the charge is removed by a charge remover (not shown) to remove the charge at the previous printing. The charging device 102 uniformly charges the peripheral surface to prepare for a new print. After this uniform charging,
The image exposure means 103 performs image exposure based on the image signal. The image exposing means 103 is, for example, a laser light emitted from a laser light source, which is rotationally scanned by a rotary polygon mirror, and is passed through an fθ lens or the like by a reflecting mirror to be charged in advance by the charger 31 on the peripheral surface of the photosensitive drum 101. A latent image is formed on the surface of the photosensitive drum 101 by being projected onto the surface.

Yellow (Y), magenta (M), cyan (C), black (BK) are provided around the periphery of the photosensitive drum 101.
A developing device 104 filled with a developer composed of a mixture of a toner and a magnetic carrier is provided. The developing device 104 includes a yellow (Y) developing device 104Y, a magenta (M) developing device 104M, a cyan (C) developing device 104C, and
The black (BK) developing device 104BK is configured to supply the yellow (Y), magenta (M), cyan (C), and black (BK) color toners from the toner supply cartridge 105. First, the developing device 10 for the first color
Development is performed by 4Y. After the development of the first color is completed in this way, the image forming process of the second color (magenta) is started, the photosensitive drum 101 is again uniformly charged by the charger 102, and a latent image based on the image data of the second color is formed. It is formed by the exposure means 103. Third color (cyan), fourth color (black)
As for the second color, the same image forming process as that for the second color is performed, and a total of four colors are developed on the photosensitive drum 101.

On the other hand, the paper feed cassette 107 is used by the paper feed cassette 106.
The recording paper P, which is the transfer material fed by the
8 is conveyed and detected by a detection member (not shown), and then temporarily stopped by the registration roller 109, and the registration roller is aligned with the multicolor image of four colors formed on the photosensitive drum 101.
After the recording paper P is fed from 109, the photoconductor drum 101 and the transfer belt 111 are transferred by the transfer device 112 using the transfer belt 111.
It is fed to the nip part (transfer area) formed between
The multicolor image on the peripheral surface of the photosensitive drum 101 is collectively transferred to the recording paper P. Next, the recording paper P is separated from the photosensitive drum 101 and further conveyed by the transfer device 112, and the separated recording paper P is conveyed to the fixing device 115 composed of the heating fixing roller 113 and the pressure bonding roller 114. The heating fixing roller 1
By applying heat and pressure between the pressure roller 13 and the pressure roller 114, the toner of the multicolor image on the recording paper P is melted and fixed on the recording paper P. Paper ejection tray 100A provided at the upper position of the image forming apparatus 100
Is ejected. The paper discharge tray 100A is provided in the image forming apparatus 100.
A part of the shaft is rotatably supported by a shaft 100B.

Reference numeral 117 denotes a cleaning device for the photosensitive drum 101, which cleans the surface of the photosensitive drum 101 after transferring a multicolor image onto the recording paper P.

In particular, the image forming apparatus 100 according to this embodiment includes a photosensitive drum 101, the charger 102, and a cleaning device 11.
7 and a process unit 118 provided with an opening / closing handle 118C and an opening / closing lid 118A rotatably provided by a shaft 118B.
The process unit 118 is detachably provided in the image forming apparatus 100. A detection member S1 is provided in a part of the process unit 118, a detection member S for detecting the detection member S1 is provided in a part of the image forming apparatus 100, and the process unit 118 is installed in the image forming apparatus 100. At this time, the detection member S detects the detection member S1, and the controller C detects the attachment / detachment of the process unit 118.

FIG. 2 is a perspective view showing a state in which the process unit 118 is taken out from the image forming apparatus 100.
When the process unit 118 is taken out from the image forming apparatus 100, the paper discharge tray 100A shown in FIG. 1 is opened around the shaft 100B and taken out. As described above, the photoconductor drum 101, the charger 102, and the cleaning device 117 are provided in the process unit 118. In particular, since the charger 102 can be replaced, As described above, the opening / closing lid 118A is partially provided on the shaft 118B so as to be freely opened and closed in the direction of the arrow.

FIG. 3 shows the process unit 118 of FIG.
In a perspective view taken out from the image forming apparatus 100, the opening / closing lid 118A is opened by using the opening / closing handle 118C, and the charger is
The state where 102 is removed from the mounting portion 118D provided in the process unit 118 and taken out is shown. Then, a new charger 102 is attached to the mounting portion 118D and exchanged.

Further, as shown in FIGS. 2 and 3, the charger 102 can be replaced even when the process unit 118 is installed in the image forming apparatus 100. That is, as shown in FIG.
First, the paper discharge tray 100A is opened above the image forming apparatus 100 around the shaft 100B, so that the process unit 118 is released. Next, the process unit 118
The opening / closing lid 118A provided on the above is opened upward by using the opening / closing handle 118C, and the charger 102 is attached to the mounting portion 118D as shown in FIG.
It is possible to remove more. Then, the newly prepared charger 102 is attached to the paper discharge tray 10 opened from the image forming apparatus 100.
It can be inserted and attached from 0A and the opening / closing lid 118A position of the process unit 118.

Further, as described above, the process unit 118
Since the photoconductor drum 101 and the charger 102 are provided in the image forming apparatus 100, when the photoconductor drum 101 has been used up and is replaced, the process unit 118 itself together with the charger 102 is used for the image forming apparatus 100. Just replace it.

FIG. 4 shows the process unit 118, detection means for detecting replacement of the charger 102, and initial setting means.

Now, for example, when the photosensitive drum 101 whose usable endurance limit is 80,000 sheets is used, the number of times the charger 102 cannot be used due to contamination by toner or the like is input to the controller C. When the counter 119 counts the number of times of use to, for example, 50,000 sheets, the controller C displays the display device 12
For example, "0" is displayed on the screen, or the image is displayed on the image forming apparatus 100 by the control device C together with the display.
Alternatively, the charger 102 may be replaced and the charger 102 may be replaced.

To replace the charger 102, the discharge tray 100A is opened around the shaft 100B as a fulcrum as shown in FIG. 1, and the opening / closing lid 118A of the process unit 118 is opened by the opening / closing handle 118C. By the above operation, as shown in FIG. 3, the charger 102 is removed from the mounting portion 118D, and a new charger 102 is mounted on the mounting portion 118D. In this way, the control means for detecting the replacement of the charging device 102 and performing the initial setting is provided in the control device C, and the method shown in FIG. 5 is used.

The initial setting can be performed for a new process unit 118 when the photosensitive drum 101 and the process unit 118 having the built-in charger 102 are replaced.

Further, the initial setting of the charger 102 can be performed via the process unit 118.

This method is disclosed in Japanese Patent Application Laid-Open No. 6-51585, and as shown in FIG. 5, the image forming apparatus 100 is provided with a replaceable process unit 118 or a charger 102. The forming apparatus 100 includes the process unit 118 and a storage unit A1 indicated by a dotted line so as to store the state in which the charger 102 is new, and the process unit 118 or the charger 102 is new or used. When the power supply circuit A3 of the image forming apparatus 100 is "ON", the determining unit A2 determines whether the process unit 118 is attached to the image forming apparatus 100 and the detecting member S detects the detecting member S1 shown in FIG. Then, all the fuses F1 to the charger 102
When F2 is connected and the storage means stores that the entire device is new, it is determined that the entire device is new, and when it is determined that the device is new, for example, the process unit 118 or the charger. If necessary, the initial setting process executing means A4 executes the initial setting process. When it is determined that the entire image forming apparatus 100 is new, the initial setting process execution unit A4 sets the copy count to 0, for example, as an operation required for stable image formation. Next, the fuses F1 and F2 are blown by the blowout hand cut A5 in which the fuses F1 and F2 are forcibly energized by the power supply circuit A3 to be blown by the initialization processing execution means A4.

When the image forming apparatus 100 uses only black (BK), the initial setting processing execution means A4 inputs mono-black image information to the storage means A1 in the control device C, and the charger 1
The replacement time of 02 is set to, for example, about 80,000 sheets, which is the same as the photosensitive drum 101. Also, the process unit 118
At the same time, the setting may be input so that the replacement is performed. And
When performing color image formation, use the photoconductor drum 10 as described above.
Set shorter than the service life limit of 1.

As shown in FIG. 6, when the charging device 102 is replaced, it is detected by the charging device 102 in order to detect whether the charging device 102 is correctly installed in the mounting portion 118B of the power supply circuit A3. A member S5 for detection is provided, and a detection member S4 for detecting the member S5 for detection is installed in the process unit 118. If there is an abnormality when the image forming apparatus 100 is energized, the display device 120 displays, for example, "Tiden key". The image is displayed or the image forming apparatus 100 is stopped.

Further, a charger 102 is installed and a power circuit A3
An energization detecting means A7 for detecting the energization state is provided, and after the image forming apparatus 100 is energized, the presence or absence of an abnormality in the energization state is detected. Is displayed or the image forming apparatus 100 is stopped. As a means for detecting whether or not there is an abnormality in the energized state, the means disclosed in Japanese Patent Laid-Open No. 6-51625 is used to store a normal current value at the time of charging the photoconductor drum 101 by the charger 102 with electric charges. After the replacement, the value may be determined to be abnormal if there is a change in the current value after replacement.

Further, as shown by a chain line in FIG. 4, the image forming apparatus 10
In the state before shipment of 0, it is stopped by the determination stop means A6 for stopping the determination means A2 for determining whether the product is new or used, and the initial setting process of the process unit 118 or the charger 102 and the fuse are performed. The fusing of F1 and F2 is also stopped.

FIG. 7 shows another embodiment of the present invention. An image forming apparatus 200 is a photosensitive drum 201 formed of a transparent member coated with an OPC photosensitive member. A plurality of exposure optical systems 202, 203, 204, 205, which are a combination of LEDs and self-hook lenses, are radially formed,
It is arranged along the inner surface of the base of the photoconductor drum 201. In the exposure optical systems 202, 203, 204 and 205, image signals of respective colors read by separate image reading devices are sequentially taken out by a memory and input to the exposure optical systems 202, 203, 204 and 205 as electric signals, respectively. The emission wavelength of the light emitting device used in this example is in the range of 600 to 800 nm.

The exposure optical systems 202, 203, 204, 205 may be composed of a combination of an optical shutter member such as LCD, LISA, PLZT, etc., and an image forming lens such as a self-hook lens, in addition to the above-mentioned light emitting elements.

206Y, 207M, 208C, and 209BK are yellow (Y), magenta (M), cyan (C), and black (B).
K) is a developing device containing each developer and is provided at a predetermined distance from the peripheral surface of the photosensitive drum 201. The developing device 206Y, 207M, 208C, 209BK is provided with a yellow color. (Y), magenta (M), cyan (C), and black (BK) developer replenishing means 210, 211, for replenishing each developer
212 and 213 are provided respectively. Reference numeral 214 denotes a blade-shaped cleaning device, and the waste toner after cleaning the surface of the photosensitive drum 201 by the cleaning device 241 is stored in the waste toner container 216 from the cleaning device 241 by using the conveying means 216. To configure.

Further, chargers 300, 301, 302, 303 are provided at regular intervals on the front side of the exposure optical systems 202, 203, 204, 205 and in the vicinity of the outer side of the photosensitive drum 201 with respect to the rotation direction of the photosensitive drum 201.

Then, the photosensitive drum 201, the exposure optical systems 202, 203, 204, 205, and the developing devices 206Y, 207M, 2
08C, 209BK, developer replenishing means 210, 211, 212, 213, the cleaning device 241, and the waste toner container 216 are integrally combined as shown in the figure to form a process unit 200C, which is provided in the image forming apparatus 200. Receiving member 200D,
Place and fix the process unit 200C on 200E.

A cutout portion 200F for transferring an image from the photosensitive drum 201 to the recording paper P is formed under the process unit 200C, and a part of the photosensitive drum 201 is exposed. Further, a detecting member S2 is fixedly provided below the process unit 200C, and a detecting member S3 for detecting the detecting member S2 is provided in the image forming apparatus 200. The process unit 200C is a receiving member 200D, When mounted and fixed on the 200E, the detection member S2 is detected by the detection member S3, and the attachment / detachment of the process unit 200C is detected by the control device C1.

Next, an image forming process of the process unit 200C of the embodiment shown in FIG. 7 will be described. This embodiment particularly uses a plurality of exposure optical systems and a charger. First, the original image is an image read by an image sensor in an image reading apparatus separate from the image forming apparatus 200, or an image edited by a computer,
The image signals of yellow (Y), magenta (M), cyan (C), and black (BK) are temporarily stored and stored in the memory.

When the image recording is started, the photosensitive drum 20
1 is rotationally driven to rotate in the clockwise direction, and at the same time, the charging operation of the charger 300 starts to apply the electric charge to the photosensitive drum 201.

After the charge is applied to the photosensitive drum 201,
In the exposure optical system 202 (Y), the first color signal,
That is, image exposure is started by an electric signal corresponding to the yellow (Y) image signal, and the electrostatic latent image corresponding to the yellow (Y) image of the original image is formed on the photosensitive layer on the surface of the photosensitive drum 201 by rotational scanning. The image forms.

The electrostatic latent image is reversely developed by the developing device 206Y in a non-contact state, and the yellow (Y) toner image is formed according to the rotation of the photosensitive drum 201.

Next, the photosensitive drum 201 is further charged with electric charges by the charging action of the charger 301 on the yellow (Y) toner image, and the color signal of the exposure optical system 203 (M), that is, the magenta ( Image exposure is performed by an electric signal corresponding to the image signal of M), and non-contact reversal development is performed by the developing device 207M so that the toner image of magenta (M) is sequentially superimposed on the toner image of yellow (Y). It is formed.

By the same image forming process as described above, the cyan (C) toner image corresponding to the third color signal is further generated by the charger 302, the exposure optical system 204 (C) and the developing device 208C, and the last charger. 303, the exposure optical system 205 (BK), and the developing device 209BK, the black (B
The toner images of K) are sequentially superimposed and formed, and a color toner image is formed on the peripheral surface of the photosensitive drum 201 within one rotation of the photosensitive drum 201.

As described above, the process unit 200C transfers the color toner image formed on the surface of the photosensitive drum 201 to the recording paper P. Therefore, the recording paper P is fed in the lower position of the image forming apparatus 200. A cassette 207 is provided, the recording paper P is fed by the paper feed roller 217, fed by the transport roller 218 to the registration roller 219, and temporarily stopped. Then, when the color toner image formed on the peripheral surface of the photosensitive drum 201 moves to the transfer position of the cutout portion 200F, the recording paper P is also fed to the transfer position.
To transfer the color toner image onto the recording paper P.
220 is transferred, and the separator 221 transfers the recording paper P to the photosensitive drum.
After separating from 201, the recording paper P is conveyed to the fixing device 223 by the conveying device 224, and the color toner image is thermally fixed on the recording paper P. The recording paper P on which the fixing is completed is conveyed by the conveying rollers 224,
The sheet is conveyed by 225, and discharged from the sheet discharge roller 226 to a sheet discharge tray 200A provided on the upper portion of the image forming apparatus 200.

FIG. 8 shows the process unit 200C of FIG.
3 is a perspective view of the image forming apparatus taken out from the image forming apparatus 200. FIG. The process unit 200C is configured such that the sheet discharge tray 200A provided on the upper portion of the image forming apparatus 200 is opened upward with a shaft 200B as a fulcrum, and the process unit 200C mounted and fixed on the receiving members 200D and 200E is fixed to the image forming apparatus 200. Take out more. By opening a part of the machine frame that constitutes the process unit 200C, the charger 303 is taken out from the process unit 200C,
FIG. 6 is a configuration diagram of replacing with a new charger 303. Charger 303
Is attached to an appropriate mounting portion (see mounting portion 118D in FIG. 3) provided in the process unit 200C, and the charger 30
3,302,301,300 can be exchanged sequentially.

FIG. 9 shows the process unit 200C, detection means for detecting replacement of the chargers 300, 301, 302, 303, and initial setting means.

Now, for example, when using the photosensitive drum 201 whose usable endurance limit is 80,000 sheets, the chargers 300, 301, 30
The number 2,303 of the number of times it cannot be used due to contamination by toner or the like is input to the control device C1.
When the number is counted as 50,000 sheets by 27, the control device C
For example, “Taiden Koukan” or the like may be displayed on the display device 228 from 1 or the image forming apparatus 200 may be stopped and the chargers 300, 301, 302, 303 may be replaced by the controller C1 together with the display.

To replace the chargers 300, 301, 302, 303, the discharge tray 200A is opened with the shaft 200B as a fulcrum as shown in FIG. 7, and the process unit 200C is taken out as shown in FIG. By the above operation, as shown in FIG.
Remove 300, 301, 302, 303 and install a new charger. As described above, the control means for detecting the replacement of the charging devices 300, 301, 302, 303 and for performing the initial setting is provided in the control device C1, and the method shown in FIG. 5 is used as described above.

The initial setting is the process unit 2 including the photosensitive drum 201 and the chargers 300, 301, 302, 303.
When 00C is replaced, it can be done for new process unit 200C. Furthermore, the initial settings of the chargers 300, 301, 302, 303 can be performed via the process unit 200C.

A replaceable process unit 200C or chargers 300, 301, 302, 303 are provided for the image forming apparatus 200, and the state in which the process unit 200C and the chargers 300, 301, 302, 303 are new is stored in the image forming apparatus 200. Similarly, including a storage unit A1 indicated by a dotted line, the determination unit A2 for determining whether the process unit 200C or the charger 300, 301, 302, 303 is a new product or a used one is a power supply circuit A3 of the image forming apparatus 100. When the unit 200C is attached to the image forming apparatus 200 and the detection member S2 shown in FIG. 7 is detected by the detection member S2, the charger 30
When all the fuses F1, ..., F2 are connected to 0,301,302,303 and the storage means A1 stores that the entire device is new, it is determined that the entire device is new, and when it is determined that it is new, For example, the process unit
200C or the charger 300, 301, 302, 303 is initialized by the initialization process execution means A4 as required. When it is determined that the entire image forming apparatus 200 is new, the initial setting process executing unit A4 performs an operation required for stable image formation. At this time, for example, the copy count is set to 0. Next, the fuses F1 ... F2 are forcibly energized by the power supply circuit A3 to fuse the fuses F1.
F2 is blown.

Further, when the image forming apparatus 100 uses only black (BK), the initial setting processing execution means A4 inputs mono-black image information to the storage means A1 in the control device C1 and charges the charger.
The replacement time of 300, 301, 302, 303 is set to, for example, about 80,000 sheets, which is the same as the photosensitive drum 201, or only the charging device 303 for mono black is replaced. Also, the process unit 200C
At the same time, the setting may be input so that the replacement is performed. And
When performing color image formation, use the photoconductor drum 20 as described above.
Set shorter than the service life limit of 1.

Further, as shown in FIG. 6, also in this embodiment,
When the charger 300,301,302,303 is replaced, the charger 300,3
In order to detect whether the power source circuit A3 is correctly installed at the above-mentioned mounting position for 01, 302, 303, the charger 300, 301, 302,
303 is provided with a detecting member S5, and the detecting member S4 for detecting the detecting member S5 is installed in the process unit 200C,
If there is an abnormality when the image forming apparatus 200 is energized, the display device 2
For example, display "Taiden Kijo" on 28
The image forming apparatus 100 is stopped.

Further, the chargers 300, 301, 302, 303 are installed,
Energization detecting means A7 for detecting the energization state from the power supply circuit A3
Is provided, after the image forming apparatus 200 is energized, it is detected whether or not there is an abnormality in the energized state.
The image forming apparatus 200 is stopped. As means for detecting whether or not there is an abnormality in the energized state, the means disclosed in Japanese Patent Application Laid-Open No. 6-51625 is used to store a normal current value at the time of applying charges to the photoconductor drum 201 by the chargers 300, 301, 302, 303. After the replacement, the value may be determined to be abnormal if there is a change in the current value after replacement.

Further, as indicated by a chain line in FIG. 4, the image forming apparatus 20
In the state before shipment of 0, the discrimination means A2 for discriminating whether it is a new article or a used one is stopped by the discrimination stopping means A6, and the process unit 200C or the charger 300, 30 is stopped.
Initial setting processing of 1,302,303 and the fuses F1, F2
The fusing is also stopped.

[0053]

As described above, the present invention provides claim 1.
In the image forming apparatus, in which at least the photosensitive drum and the charger are integrated with each other, the image forming apparatus forms a color image replaceable by the image forming apparatus, and only the charger can be replaced by the process unit. Therefore, it is possible to use the process unit with the built-in photoconductor drum without wasting it together with the replacement of the charger. In addition, since a new charger can always apply good charges to the photoconductor drum efficiently, good color image formation can be performed.

In the second aspect of the present invention, by replacing the charger from the process unit before the number of times the photosensitive drum has been used, good charges can be applied to the photosensitive drum. Further, since the display unit for replacing the charger is provided for the process unit and / or the image forming apparatus, it is not necessary to forget to replace the charger.

In the third aspect of the present invention, since the charger can be replaced even when the process unit is attached to the image forming apparatus main body, the process unit is detached from the image forming apparatus main body when replacing the charger. No need to
The charger can be replaced quickly.

According to a fourth aspect of the present invention, the charging device is changed at a replacement time depending on whether the image forming apparatus performs a single color (mono black) image formation or a full color image formation, and the charging device is charged at a time suitable for the usage time of the charging device. You can replace the vessel without waste.

In the fifth aspect, when the photosensitive drum reaches the endurance, the process unit having the built-in charger may be replaced by the image forming apparatus, and the replacement work is easy.

According to a sixth aspect of the present invention, when the charging device provided in the image forming apparatus for charging the photosensitive drum is replaced, the replacement time is displayed on the image forming apparatus to forget to replace the charging device. By preventing it, the color image formation can be well maintained.

In the seventh aspect, when the charger is replaced with respect to the image forming apparatus, the newly provided charger is initialized and the number of times of use of the newly provided charger is started. Since it is possible, the charger can be replaced accurately.

According to the eighth aspect of the present invention, by detecting the electrification state of the charging device provided in the image forming apparatus, the electrification failure of the charging device can be prevented. In particular, when a plurality of charging devices are used, the color of the color image Good balance can be maintained.

According to the ninth aspect of the present invention, by detecting the amount of charge on the surface of the photoconductor drum by the charger, it is possible to always apply a normal charge to the surface of the photoconductor drum, and to obtain a good color image. Can be formed.

[Brief description of drawings]

FIG. 1 is an overall sectional view showing an image forming apparatus of the present invention.

FIG. 2 is a perspective view showing a process unit for image formation of the present invention.

FIG. 3 is a perspective view showing replacement of a charger from the process unit shown in FIG.

FIG. 4 is an overall configuration diagram showing control in the image forming apparatus of the present invention.

FIG. 5 is a block configuration diagram showing initial settings of a process unit and a charger according to the present invention.

FIG. 6 is a configuration diagram showing a detection unit that detects the position of the charger of the present invention.

FIG. 7 is an overall configuration diagram showing another image forming apparatus of the present invention.

FIG. 8 is a perspective view showing another process unit for image formation of the present invention.

FIG. 9 is an overall configuration diagram showing control in another image forming apparatus of the present invention.

[Explanation of symbols]

 100,200 Image forming device 118,200C Process unit 101,201 Photosensitive drum 102,300,301,302,303 Charger C, C1 Control device 119,227 Counter 120,228 Display device

Claims (9)

[Claims] 1. An image forming apparatus having an image carrier and a process unit including a single charging unit or a plurality of charging units, wherein the charging unit is replaceable with respect to the process unit. Image forming apparatus. 2. A display unit and / or an image forming unit that sets the number of times the charging unit is set to be used to the number of times the image carrier is set to be used, and displays the replacement of the charging unit to the process unit. The image forming apparatus according to claim 1, further comprising control means for stopping the apparatus. 3. The image forming apparatus according to claim 1, wherein the charging unit is replaceable by the process unit in a state where the process unit is attached to the image forming apparatus. 4. The charging means changes the set number of times of use when forming a single color image and the set number of times of use when forming a color image by the image forming apparatus, and exchanges from the image forming apparatus by setting the number of times of use. The image forming apparatus according to claim 1, wherein the image forming apparatus is set so as to differ in time. 5. The image forming apparatus according to claim 1, wherein the charging unit is set at the same time as the replacement time of the image carrier. 6. An image forming apparatus having an image carrier and a charging means, a counting means for reading the number of times of use of the charging means provided in a process unit for image formation, and a predetermined number of times of use by the counting means. And a display device for displaying the replacement of the charging means when counted. 7. An image forming apparatus having an image carrier and a charging means, wherein when a charger is replaced with respect to the image forming apparatus, the replaced charging is carried out prior to the image formation by the image carrier. An image forming apparatus, comprising: an initial setting means for setting that the number of times of use of the container is initial use. 8. An image forming apparatus having an image carrier and a charging means, wherein the image forming apparatus, a detecting means for detecting an energized state of the charging means, and an energized state detected by the detecting means An image forming apparatus comprising: a display unit for displaying and / or a control unit for stopping the image forming apparatus. 9. A control means for detecting a charging state of the image carrier by energizing the charging means, a display means for displaying the charging state detected by the detecting means, and / or a control for stopping the image forming apparatus. 9. The image forming apparatus according to claim 8, further comprising means.