JP2000019901A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely judge a service life of a photoreceptor without providing a specific counting means at the photoreceptor. SOLUTION: This image forming device is provided with an exposing means 40 for forming a latent image by exposing a surface of the photoreceptor 140 to be rotated and driven, a developing means for making the latent image into the visible image by applying the developer on the latent image, an intermediate transfer body 36 for primarily transferring the visible image and further secondarily transferring on a recording materials, a detecting means 91 for detecting a mark disposed on the intermediate transfer body, and a controlling part 90 controlling exposure timing by the exposing means by making the time when the mark is detected as a reference, counting detected times of the mark and judging that the photoreceptor reaches the service life when the counted value reaches a specific value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a printer, a facsimile, a copying machine, etc. for forming an image by using an electrophotographic technique. In particular, the present invention relates to a technique for determining the life of a photoconductor in an image forming apparatus capable of forming a full-color image.

[0002]

2. Description of the Related Art Generally, an image forming apparatus using an electrophotographic technique includes a photosensitive member having a photosensitive layer on an outer peripheral surface, a charging device for uniformly charging the outer peripheral surface of the photosensitive member, and one charging device. Exposure means for selectively exposing the charged outer peripheral surface to form an electrostatic latent image, and applying a toner as a developer to the electrostatic latent image formed by the exposure means to form a visible image The image forming apparatus includes a developing unit that forms a (toner image), and a transfer unit that transfers the toner image developed by the developing unit to a recording material such as paper.

The photoreceptor in this type of image forming apparatus has a life such that deterioration with time occurs due to voltage application due to charging, transfer, and the like, and wear due to rubbing with a contact member. It is necessary to replace the used photoconductor with a new photoconductor.

Therefore, conventionally, as a technique for judging the life of a photoconductor, a technique of counting the number of rotations of the photoconductor (for example,
JP-A-6-180518) and a technique for counting the number of sheets of recording material passing a transfer position to determine the life of a process kit including a photoreceptor (Japanese Patent Publication No. 1-41).
No. 986) is known.

[0005]

Among the above-mentioned prior arts, the technology for counting the number of rotations of the photosensitive member has a drawback that a counting means (for example, a tachometer) for performing the counting is required.

Further, there is the following problem in the technology for judging the life of a process kit including a photosensitive member by counting the number of recording materials passing through a transfer position. That is, the number of rotations of the photosensitive member corresponding to the length of the recording material of various sizes differs, and the image formed (transferred) on the recording material is a monochromatic image (for example, a monochrome image). Case and multi-color image (for example, full-color image)
, The rotation speed of the photoconductor with respect to one recording material is different. Therefore, there is a problem that the life of the photoconductor cannot be accurately determined by counting the passage of the recording material.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus which can solve the above-mentioned problems and can reliably determine the life of a photoreceptor without requiring special counting means for the photoreceptor. is there.

[0008]

According to another aspect of the present invention, there is provided an image forming apparatus, comprising: a photosensitive member driven to rotate; and a latent image formed on the surface of the photosensitive member by exposing the surface of the photosensitive member. An exposure unit that forms a visible image, a developing unit that applies a developer to the latent image formed by the exposure unit to form a visible image, and is driven to rotate, and the visible image developed by the developing unit is primarily transferred. Further, an intermediate transfer member for secondary-transferring the visible image to a recording material, a mark provided on the intermediate transfer member, detection means for detecting the mark, and the mark detected by the detection means Control means for controlling the exposure timing by the exposure means on the basis of a time point; counting means for counting the number of times the mark is detected by the detection means; and when the count value by the counting means reaches a predetermined value. Serial photoreceptor is characterized by comprising a determining means for determining that reached the end of its life.

[0009]

According to the image forming apparatus of the first aspect, the latent image is formed by exposing the surface of the photoreceptor which is driven to rotation by the exposing means, and the developer is applied to the latent image by the developing means. The visible image is primary-transferred to a rotationally driven intermediate transfer body, and then secondary-transferred to a recording material.

Therefore, when a color image is formed on a recording material, the step of transferring the visible image formed on the photosensitive member onto the intermediate transfer member is repeated a plurality of times using developers of different colors. This makes it possible to form a color image by superimposing a plurality of visible images on the intermediate transfer body and transfer the color image onto the recording material at once (secondary transfer).

The intermediate transfer member is provided with a mark,
Since the exposure timing of the exposure unit is controlled by the control unit based on the time when this mark is detected by the detection unit, the position between colors on the intermediate transfer body between the visible images of a plurality of colors to be transferred is controlled. It is possible to obtain a beautiful color image by suppressing the displacement.

According to the image forming apparatus of the present invention, there is provided a counting means for counting the number of times the mark is detected by the detecting means, and the photosensitive device is provided when the count value of the counting means reaches a predetermined value. Since the determination means for determining that the body has reached the end of its life is provided, the following operation and effect can be obtained.

That is, the rotation speed of the photosensitive member and the rotation speed of the intermediate transfer member have a corresponding relationship. For example, there is a relationship such that the intermediate transfer member makes one rotation for one rotation of the photoconductor, and one rotation of the intermediate transfer member for two rotations of the photoconductor.

Therefore, the number of rotations of the intermediate transfer member is counted by counting the number of times of detection of the mark for preventing color misregistration by the counting means. As a result, the number of rotations of the photosensitive member is counted. When the value has reached the predetermined value, the judging means judges that the photoconductor has reached the end of its life.

As described above, according to the image forming apparatus of the first aspect, the use of the mark detecting means for preventing the color misregistration prevents the need for a special counting means for the photosensitive member. The life of the photoconductor can be reliably determined.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view showing an embodiment of the image forming apparatus according to the present invention, FIG. 2 is a partially cut-away enlarged view of a photosensitive cartridge and its periphery, and FIG.
FIG. 3 is an enlarged partial cross-sectional view of FIG.

This image forming apparatus is an apparatus capable of forming a full-color image using a developing device using four color toners of yellow (Y), cyan (C), magenta (M), and black (K). .

In FIG. 1, reference numeral 100 denotes a photoreceptor cartridge which is configured to be detachable from the apparatus main body. It is driven to rotate in the direction.

The photosensitive member 140 has a flexible thin cylindrical conductive substrate 140b (see FIG. 3) and a photosensitive layer 140c formed on the surface thereof.

Around the photoreceptor 140, along a rotation direction thereof, a charging roller 160 as charging means, a developing device 10 (Y, C, M, K) as developing means, an intermediate transfer device 30, and a cleaning device Means 170 are arranged.

The charging roller 160 contacts the outer peripheral surface of the photoconductor 140 to uniformly charge the outer peripheral surface. On the outer peripheral surface of the uniformly charged photoconductor 140, a selective exposure L1 according to desired image information is performed by an exposure unit 40 serving as an exposure unit, and the electrostatic latent image is formed on the photoconductor 140 by the exposure L1. Is formed.

This electrostatic latent image is developed by applying toner in a developing device 10.

As a developing device, a developing device 10 for yellow is used.
Developing device 10C for Y and cyan, developing device 10 for magenta
A developing device 10K for M and black is provided. These developing units 10Y, 10C, 10M, and 10K are:
Each is configured to be swingable, so that only the developing roller 11 of one developing unit can selectively contact the photoconductor 140. Therefore, these developing devices 10
Develops an electrostatic latent image on the photoconductor 140 by applying any one of yellow, cyan, magenta, and black toners to the surface of the photoconductor 140. The developing roller 11
Is constituted by a hard roller, for example, a metal roller having a roughened surface, or a hard resin roller.

The developed toner image is transferred onto an intermediate transfer belt 36 of an intermediate transfer device.

The cleaning means 170 includes a cleaner blade 171 for scraping off the toner remaining on and adhering to the outer peripheral surface of the photosensitive member 140 after the transfer, and a receiving portion 172 for receiving the toner scraped off by the cleaner blade 171. It has.

The intermediate transfer device 30 includes a driving roller 31,
It has four driven rollers 32, 33, 34, 35 and an endless intermediate transfer belt 36 as an intermediate transfer member stretched around these rollers.

The drive roller 31 has a gear (not shown) fixed to the end thereof and a drive gear 190 for driving the photosensitive member 140.
(See FIG. 5), the photosensitive member 1
The intermediate transfer belt 36 is driven to rotate at substantially the same peripheral speed as the photosensitive member 140 in the direction indicated by the arrow in FIG.

The driven roller 35 is disposed at a position where the intermediate transfer belt 36 is pressed against the photosensitive member 140 by its own tension with the driving roller 31.
A primary transfer portion T1 is formed at a pressure contact portion between the intermediate transfer belt 36 and the intermediate transfer belt 36. The driven roller 35 is disposed near the primary transfer portion T1 on the upstream side in the circulation direction of the intermediate transfer belt 36.

The driving roller 31 has an intermediate transfer belt 36
A primary transfer voltage is applied to a conductive layer 36a (see FIG. 3) of the intermediate transfer belt 36, which will be described later, via the electrode roller.

The driven roller 32 is a tension roller, and urges the intermediate transfer belt 36 in the direction of its tension by urging means (not shown).

The driven roller 33 is a backup roller that forms the secondary transfer portion T2. A secondary transfer roller 38 is opposed to the backup roller 33 via an intermediate transfer belt 36. The secondary transfer roller 38
It can be moved toward and away from the intermediate transfer belt 36 by a contacting / separating mechanism (not shown). A secondary transfer voltage is applied to the secondary transfer roller 38.

The driven roller 34 is a backup roller for the belt cleaner 39. Belt cleaner 39
Is a cleaner blade 39 which comes into contact with the intermediate transfer belt 36 and scrapes off the toner remaining and adhering to the outer peripheral surface thereof.
a, and a receiving portion 39b for receiving the toner scraped off by the cleaner blade 39a. The belt cleaner 39 can be moved toward and away from the intermediate transfer belt 36 by a contact / separation mechanism (not shown).

As shown in FIG. 3, the intermediate transfer belt 36 is a multilayer belt having a conductive layer 36a and a resistance layer 36b formed on the conductive layer 36a and pressed against the photosensitive member 140. ing. The conductive layer 36a is formed on an insulating substrate 36c made of a synthetic resin, and a primary transfer voltage is applied to the conductive layer 36a via the above-described electrode roller. As shown in FIG.
The conductive layer 36a is exposed in a strip shape by removing the resistance layer 36b in a strip shape at one side edge portion, and the electrode roller comes into contact with the exposed portion. The other side edge of the belt 36 is provided with a mark M to be detected by a detection unit described later. In this embodiment, the mark M is constituted by a light transmission hole.

In FIGS. 1 and 2, reference numeral 91 denotes a transmission type optical sensor, which constitutes a detecting means for detecting the mark M. The above-described exposure L1 is started at a predetermined timing with reference to the time when the mark M is detected by the detecting means 91.

In the process of circulating the intermediate transfer belt 36, the toner image on the photosensitive member 140 is transferred onto the intermediate transfer belt 36 in the primary transfer portion T1, and the toner image transferred onto the intermediate transfer belt 36 is Is transferred to a sheet (recording material) S, such as a sheet, supplied between the secondary transfer roller 38 and the secondary transfer unit T2.

The sheet S is fed from the sheet feeding device 50,
The toner is supplied to the secondary transfer portion T2 at a predetermined timing by the gate roller pair G. 51 is a paper feed cassette, and 52 is a pickup roller.

The sheet S to which the toner image has been transferred in the secondary transfer portion T2 passes through the fixing device 60, where the toner image is fixed, passes through the paper discharge path 70, and is formed on the case 80 of the apparatus main body. The sheet is discharged onto the received sheet receiving portion 81. In this image forming apparatus, as a paper discharge path 70,
It has two paper discharge paths 71 and 72 independent of each other, and the sheet that has passed through the fixing device 60 is discharged through one of the paper discharge paths (71 or 72). The paper discharge paths 71 and 72 also constitute a switchback path. When an image is formed on both sides of the sheet, the sheet once entering the paper discharge path 71 or 72 passes through the return path 73. Then, the sheet is fed again to the secondary transfer portion T2.

A control unit 90 controls the entire apparatus. The control unit 90 controls the exposure unit 40 based on the time when the detection unit 91 detects the mark M.
Control means for controlling the exposure timing of the photoconductor 140, counting means for counting the number of times the mark M is detected by the detection means 91, and judging that the photosensitive member 140 has reached the end of its life when the count value of the counting means reaches a predetermined value. And determination means for performing the determination.

The outline of the operation of the entire image forming apparatus as described above is as follows.

(I) When a print command signal (image forming signal) from a host computer or the like (personal computer or the like) not shown is input to the control unit 90 of the image forming apparatus, each roller of the photosensitive member 140 and the developing device 10 11 and the intermediate transfer belt 36 are driven to rotate.

(Ii) The outer peripheral surface of the photosensitive member 140 is uniformly charged by the charging roller 160.

(Iii) The exposure unit 40 selectively exposes the outer peripheral surface of the uniformly charged photoreceptor 140 in accordance with the image information of the first color (for example, yellow) to form a yellow electrostatic latent image. An image is formed. Exposure L1 is
The processing is started at a predetermined timing with reference to a point in time when the mark M is detected by the detecting means 91.

(Iv) Only the developing roller of the developing unit 10Y for the first color (for example, yellow) comes into contact with the photoconductor 140, whereby the electrostatic latent image is developed, and the first color (for example, yellow) is developed. Is formed on the photoconductor 140.

(V) A primary transfer voltage having a polarity opposite to that of the toner is applied to the intermediate transfer belt 36, and the toner image formed on the photosensitive member 140 is transferred to the intermediate transfer belt 36 at the primary transfer portion T1. Is transferred to At this time, the secondary transfer roller 38 and the belt cleaner 39 are separated from the intermediate transfer belt 36.

(Vi) After the toner remaining on the photosensitive member 140 is removed by the cleaning means 170,
The photosensitive member 140 is neutralized by the neutralizing light L2 from the neutralization unit 41 (see FIGS. 1 and 2).

(Vii) The above operations (ii) to (vi) are repeated as necessary. That is, the second color, the third color, the fourth color,
Is repeated on the intermediate transfer belt 36 to form a toner image corresponding to the content of the print command signal.

(Viii) The sheet S is supplied from the sheet feeding device 50 at a predetermined timing, and immediately before or after the leading end of the sheet S reaches the secondary transfer portion T2 (in short, at a desired position on the sheet S, Secondary transfer roller 38) (at the timing when the toner image on intermediate transfer belt 36 is transferred)
Is pressed against the intermediate transfer belt 36 and a secondary transfer voltage is applied, so that the toner image on the intermediate transfer belt 36 (basically, a full-color image in which four color toner images are superimposed) is transferred onto the sheet S. Is done. Further, the belt cleaner 39 comes into contact with the intermediate transfer belt 36, and the toner remaining on the intermediate transfer belt 36 after the secondary transfer is removed.

(Ix) The toner image is fixed on the sheet S by passing the sheet S through the fixing device 60, and thereafter, the sheet S is directed to a predetermined position (or to the sheet receiving portion 81 in the case of non-double-sided printing). In the case of double-sided printing, the sheet is conveyed to the return path 73 via the switchback path 71 or 72).

The life of the photosensitive member 140 in the image forming apparatus described above is such that the photosensitive member 140 is deteriorated with time due to abrasion caused by application of a voltage due to charging, transfer or the like, or rubbing against a contact member such as the cleaner blade 171. It is necessary to replace the photoconductor 140 which has been used and has reached the end of its life with a new photoconductor 140.

Therefore, in this embodiment, as described above, the control unit 90 counts the number of times the mark M has been detected by the detection unit 91, and when the count value of the count unit reaches a predetermined value. Photoreceptor 14
The determination means for determining that 0 has reached the end of the life.

A notifying means 92 is connected to the control unit 90, and when the count value reaches a predetermined value, a notification that the photosensitive member 140 has reached the end of its life, that is, a notification that the photosensitive member 140 should be replaced. Is performed for the user. The notifying unit 92 includes a case 80 of the image forming apparatus.
And the like.

When the notification by the notification means 92 is made,
The user replaces the photoconductor 140 with a new one. In this embodiment, the photoconductor cartridge 100 is replaced because the photoconductor 140 is incorporated in the photoconductor cartridge 100. .

As shown in FIGS. 2 and 5, the photoreceptor cartridge 100 mainly includes a photoreceptor 140, a charging roller 160, a cleaning means 170, and a cartridge case 200 for holding the same. The charging roller 160 and the cleaning means 170 are
It is configured to have a life similar to that of the forty.

The cartridge case 200 has a side cover 210, and a fusing fuse 220 is attached to the inside of the side cover 210 by mounting brackets 231 and 232. Therefore, the mounting brackets 231, 23
2 is connected to the terminals 221 and 222 of the blown fuse, respectively (see FIG. 6).

On the other hand, as shown in FIGS. 5 and 6, three terminals 1a, 1b and 1c are provided at appropriate places of the apparatus main body 1, and when the photosensitive cartridge 100 is mounted on the apparatus main body 1, , The terminal 1a is the mounting bracket 231 and the terminal 1a.
And 1b are connected to the mounting bracket 232. The terminal 1b is grounded.

When a power supply (not shown) of the apparatus main body 1 is turned on, predetermined power is supplied to two terminals 1a and 1c of the three terminals. When attached to
A current is supplied to the fusing fuse 220 via a and 1b and the mounting brackets 231 and 232, and the fuse is blown.

The control unit 90 controls the three terminals 1
The following judgment is made based on the energized state of a, 1b, and 1c.

(A) When the power is turned on, a current smaller than the fusing current value of the fusing fuse 220 is applied to the terminals 1a and 1b to detect the connection state. Judge that it is attached.

(B) When the power is turned on, a current smaller than the fusing current value of the fusing fuse 220 flows through the terminals 1a and 1b to detect the connection state. When is connected, it is determined that the photoconductor cartridge 100 is mounted.

(C) If all the terminals 1a, 1b, 1c are not connected when the power is turned on,
It is determined that the photoconductor cartridge 100 is not mounted.

Then, only in the case (a), the control unit 90 blows the current higher than the fusing current value of the fusing fuse 220 to the terminals 1a and 1b, and blows the fusing fuse 220, and counts the above-mentioned count value. It is designed to reset. Therefore, if the photoreceptor cartridge 100 that has not reached the end of its life has been removed from the apparatus main body for some reason, for example, a paper jam or the like, and is mounted again, it is assumed that this is a new photoreceptor cartridge 100. No recognition is performed, and therefore, the count value is not reset.

The photoreceptor cartridge 100 is mounted on the apparatus main body 1 from the left side in FIG. 1, but the frame and the case 80 of the image forming apparatus are taken along line BB in FIG. And the exposure unit 40 (for example, the exposure unit 40 is slidable to the left), so that the photosensitive cartridge 100 can be easily attached and detached. As shown in FIG. 2 and FIG. 5, knobs 231 and 231 for facilitating attachment and detachment of the photoreceptor cartridge 100 are provided.

The photosensitive member cartridge 100 as described above
Is built into the image forming apparatus, the driving gear 19
When the drive gear (not shown) of the main body of the image forming apparatus meshes with the photosensitive drum 140, the photosensitive member 140 is driven to rotate in the direction of the arrow.

According to the image forming apparatus described above, the following operation and effect can be obtained.

Exposure L1 by the exposing means 40 is performed on the surface of the photoreceptor 140 which is rotationally driven to form an electrostatic latent image, and a developing agent is applied to the latent image by the developing means 10 to become a visible image. This visible image is rotated by the intermediate transfer body 3
6 is primarily transferred to the recording material S, and further secondary transferred to the recording material S.

Therefore, when a color image is formed on the recording material S, the step of transferring the visible image formed on the photosensitive member 140 onto the intermediate transfer member 36 is performed by using different color developers. By repeating a plurality of times, the intermediate transfer body 36
A color image is formed by superimposing visible images of multiple colors on the top, and this color image is transferred collectively onto the recording material (secondary transfer)
It is possible to form by doing.

A mark M is provided on the intermediate transfer member 36, and the exposure timing of the exposure means 41 is controlled by the control means 90 based on the time when the mark M is detected by the detection means 91. It is possible to obtain a clear color image by suppressing the positional shift between colors on the intermediate transfer member 36 between visible images of a plurality of colors.

According to this image forming apparatus, the counting means for counting the number of times the mark M has been detected by the detecting means 91, and when the count value of the counting means reaches a predetermined value, the photosensitive member 140 reaches the end of its life. The following operational effects can be obtained by providing the determination means for determining that the operation has been performed.

That is, the rotation speed of the photosensitive member 140 and the rotation speed of the intermediate transfer member 36 have a corresponding relationship. For example, there is a relationship such that the intermediate transfer member makes one rotation for one rotation of the photoconductor, and one rotation of the intermediate transfer member for two rotations of the photoconductor. In this embodiment, the intermediate transfer belt 36 makes one rotation for every two rotations of the photoconductor 140.

Therefore, by counting the number of times of detecting the mark M for preventing misregistration between colors by the counting means, the number of rotations of the intermediate transfer member 36 is counted, and as a result, the number of rotations of the photosensitive member 140 is counted. When the count value reaches a predetermined value, the determining means determines that the photosensitive member 140 has reached the end of its life.

As described above, according to this image forming apparatus, the use of the detecting means 91 of the mark M for preventing misregistration between colors allows the photosensitive member 140 to be operated without any special counting means. The life of 140 can be reliably determined.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be appropriately modified within the scope of the present invention.

For example, the mark M is formed of a light transmitting hole, but may be formed of a light reflecting seal or the like. In that case, the detecting means 9
Reference numeral 1 can be constituted by a reflection type optical sensor.

The intermediate transfer member is not limited to a belt, but may be constituted by an intermediate transfer drum.

[0076]

According to the image forming apparatus of the first aspect,
By using the detecting means of the mark M for preventing the color misregistration, the life of the photoconductor can be reliably determined without requiring any special counting means for the photoconductor.

[0077]

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a partially cut-away enlarged view of a photoreceptor cartridge and its periphery.

FIG. 3 is an enlarged partial sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a partial plan view of the intermediate transfer belt 36.

FIG. 5 is a partially exploded perspective view of the photoreceptor cartridge.

FIG. 6 is a circuit diagram showing a relationship between the apparatus main body and a fuse for blowing a photoreceptor cartridge.

[Explanation of symbols]

 S Recording material 10 Developing device (developing means) 36 Intermediate transfer member M mark 40 Exposure unit (exposure means) 91 Optical sensor (detection means) 90 Control unit (control means, counting means, judgment means) 140 photoconductor

Claims (1)

[Claims] 1. A photoconductor that is driven to rotate, an exposure unit that exposes the surface of the photoconductor to form a latent image on the surface of the photoconductor, and applies a developer to the latent image formed by the exposure unit. A developing unit that converts the visible image developed by the developing unit into a primary image, and further secondary-transfers the visible image to a recording material; A mark provided on the intermediate transfer member, a detecting means for detecting the mark, a control means for controlling an exposure timing by the exposing means based on a point in time when the mark is detected by the detecting means, Counting means for counting the number of times the mark has been detected; determining means for determining that the photosensitive member has reached the end of its life when a count value of the counting means has reached a predetermined value;
An image forming apparatus comprising: