JP3108174B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detecting means for detecting the unused life of a photoreceptor when the photoreceptor is mounted on an apparatus body in order to judge the life of the photoreceptor. And an image forming apparatus such as a printer, a copier, a facsimile, etc.

[0002]

2. Description of the Related Art Since a photosensitive member provided in an image forming apparatus such as a printer or a copying machine is a consumable part, it needs to be replaced with a new one when used for a long time.
Conventionally, the service life of a photoreceptor is judged by the serviceman looking at the photoreceptor and checking the wear (fatigue) state, or by automatically counting the number of prints and the rotation time of the photoreceptor. When the measured value has reached the value, the operator has been notified by indicating that the photoconductor has reached the replacement time (lifetime).

As described above, when the replacement time of the photosensitive member is determined based on the count value obtained by counting the number of prints and the rotation time of the photosensitive member, when a new photosensitive member is set and replaced, the count is counted. Since the value must be reset, it is necessary to output a signal to the control system (CPU) that performs counting at the time of the replacement, informing that a new unused photoconductor is set by some method. Therefore, conventional printers, etc.,
In addition to the detecting means for detecting that the photoconductor has been set in the apparatus main body, a switch for notifying the control system when a new photoconductor (unused) is set by replacement or the like is provided. Some sensors are provided with a sensor for detecting that the photoconductor has been set.

[0004]

However, if the serviceman judges the wear time by looking at the photoconductor, it is not only poor workability but also the judgment criteria for the serviceman differ depending on the serviceman. There is no efficient replacement. Also, in order to automatically count the number of prints and the rotation time of the photoconductor and display it when the count value reaches a preset value, it is necessary to replace it with an unused photoconductor when it is replaced. It is necessary to provide a switch for notifying the control system and resetting the count value, or a sensor for detecting that an unused photoconductor has been set, so that there is a problem that the cost increases accordingly. Was.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it has been made possible to detect an unused new photoconductor when it is set without increasing the cost relatively. It is an object of the present invention to make it possible to efficiently and easily replace a photoconductor whose life has expired.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is in a first position when not in use,
When the photoconductor is rotated by being set on the main body of the apparatus, the second
A photoreceptor unit that includes a detected member that moves to a position of the photoconductor unit that can be attached to and detached from the apparatus main body;
The first detection is performed at a predetermined timing by the detection means, and then the photosensitive element is rotated, and after a certain time has passed, the detection means performs the second detection again, and the first and second detections are performed. Depending on the combination of the results, a photoreceptor mounting determination unit that determines whether an unused photoreceptor unit is set in the apparatus main body, a photoreceptor unit in use is set, or a photoreceptor unit is not set. And an image forming apparatus.

A detecting member which is at a first position in an unused state and moves to a second position when the photosensitive member is set and rotated in the apparatus main body; A possible photoreceptor unit, detection means for detecting whether or not the detected member is at the second position at a predetermined position, and first detection at a predetermined timing by the detection means, If the detected member is not at the second position according to the detection result, the photosensitive member is rotated, and after a predetermined time, the detecting means performs the second detection again, and the first and second detections are performed.
Based on the combination of the first detection result, it is determined whether an unused photoconductor unit is set or the photoconductor unit is not set. If the first detection result indicates that the detected member is at the second position, The image forming apparatus is provided with a photoreceptor mounting determination unit that determines that the photoreceptor unit in use is set.

Further, in the above-mentioned image forming apparatus, when the power of the apparatus is turned on or when the cover of the apparatus main body is closed, the first detection by the detecting means is performed or the photosensitive unit is replaced. The first detection by the detecting means may be performed only when the cover that is opened and closed is opened and then closed. More effective.

[0009]

According to the image forming apparatus constructed as described above, when the unused member at the first position is set in the apparatus main body, the detection is performed at a predetermined timing by the detecting means. When the first detection detects that the member is not at the second position, and then the photosensitive member is rotated to move the detected member to the second position and a certain time has elapsed,
This time, the second detection detects that the detected member is at the second position.

Therefore, the combination of the detection results of the first and second detected members, that is, the detected member is not at the second position in the first detection, but is in the second position in the second detection. Since it is possible to determine that an unused photoconductor unit has been set based on a combination of certain detection results, it is possible to know the accurate usage time of the photoconductor by starting counting the rotation time of the photoconductor from this point. Because you can
The photosensitive member can be efficiently replaced.

Further, a detecting means similar to the above is provided, and the detected member is set to the second detection result by the first detection result by the detecting means.
If it is not at the position, the photosensitive member is rotated, and after a certain period of time, the detection means again performs the second detection. If the detected member is at the second position based on the first detection result, the photosensitive member in use is detected. If the photoreceptor mounting determination means for determining that the photoreceptor unit is set is provided, the photoreceptor unit in use is taken out once at the time of maintenance or the like, and when the photoreceptor unit is set again in the apparatus main body, the first time. Since the detected member is detected as being at the second position in the detection result, it is determined that the photoconductor unit in use has been set, so that it is not necessary to perform the second detection thereafter. As a result, the wear (fatigue) of the photoconductor can be reduced by eliminating the need to rotate the photoconductor for detection.

Further, when the power of the apparatus is turned on or the cover of the apparatus main body is closed, the first detection by the detecting means is performed, and the cover which is opened and closed when the photosensitive unit is replaced is provided. If the first detection is performed by the detecting means only when the photoconductor is opened and then closed, the frequency of rotation of the photoconductor for determining the mounting of the photoconductor can be reduced, and the photoconductor can be further reduced. Consumption can be suppressed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic view showing a main part of a photoreceptor unit which can be set in an apparatus main body of an image forming apparatus according to an embodiment of the present invention, and FIG. 2 is an overall configuration diagram showing a laser printer which is also the image forming apparatus. is there. The laser printer shown in FIG. 2 has a photoreceptor unit 2 provided with a belt-shaped photoreceptor 3 at a substantially central portion in an apparatus main body 1, which is detachably provided.
Around the photosensitive unit 2, a charger 12, a developing unit 13, a transfer unit 14, and a cleaning unit 15 are arranged along the rotating direction of the photosensitive body 3 rotating in the direction indicated by the arrow.

An optical writer 16 is provided below the charger 12 and the cleaning device 15, and a paper cassette 18 for storing the paper P therein is provided below the optical writer 16. At the same time, a paper feed roller 27 is provided on the paper sending side so as to be rotatable in the direction indicated by the arrow.

A manual paper feed tray 20 also serving as a paper discharge tray is provided on the front side of the apparatus main body 1, that is, on the upper right side in FIG. 2, and on the left rear side, thick paper such as a postcard. Is provided with a paper discharge stack unit 21 capable of discharging paper. A discharge unit 22 and a discharge stack unit 23 are provided on the upper surface of the apparatus main body 1. The discharge unit 22 is provided with discharge rollers 24 and 25 that press against each other in the vertical direction.

In this laser printer, at the time of paper feeding, the paper feeding roller 27 at the lower portion of the apparatus main body 1 shown in FIG. The sheet P is conveyed to the upper side of the photoconductor 3 at a timing by a registration roller 29 provided on a sheet feeding path. The photoreceptor 3 is rotated in the direction indicated by the arrow in FIG. 2 (counterclockwise direction), and the surface thereof is uniformly charged by the charger 12, and the laser beam from the optical writer 16 is there. Irradiates an electrostatic latent image.

The latent image is visualized by toner when passing through the developing device 13, and the visible image is transferred by the transfer device 14 to the lower surface of the sheet P conveyed above the photoconductor 3. You. The paper P on which the visible image is transferred is placed on the fixing device 3.
And is fixed between the heating roller 31 and the pressing roller 32.

Then, the sheet P is conveyed by a sheet discharging roller 33 and guided upward by a sheet conveying guide 34, and is conveyed sequentially by sheet discharging rollers 35, 36, and 37 through a sheet conveying path 38 to perform double-sided recording. When the instruction to perform is issued, the switching guide 39 causes the discharge rollers 40,
The rollers are guided to the side 41, and a part of the leading end side is once discharged onto the manual feed tray 20 by the rollers.

Next, the paper discharge roller 41 is rotated in the reverse direction to switch back the paper, and the paper P is sent to the photosensitive member 3 through the transport path 43 with the image surface turned upside down. Then, recording (transfer of an image) is performed on the lower surface side, and the image is discharged. On the other hand, when the double-sided recording is not performed, the sheet P is guided to the sheet conveying path 42 of the discharge unit 22 by the switching guide 39, and the image surface is turned upside down by the discharge rollers 24 and 25. To discharge onto the discharge stack section 23.

When the paper P is thick paper, the switching direction is switched by the switching guide 44 so as to be substantially linear.
The sheet P is discharged onto the discharge stack unit 21. While discharging the paper in this manner, the photosensitive member 3 after the transfer of the visible image is cleaned by the cleaning device 15 to prepare for the next image recording.

When the photosensitive member unit 2 is not used, it is at the first position shown by a solid line in FIG. A detected member 52 that rotates to a second position indicated by a line is provided.

The laser printer has a photo-interrupter (for example, a transmission type photo-detector) which is a detecting means for detecting whether or not the detected member 52 is at the second position at a predetermined position shown in FIGS. Sensor) 5 and the photo interrupter 5 to perform the first detection at a predetermined timing, and then rotate the photoreceptor 3 and after a certain period of time, perform the second detection by the photo interrupter 5 again. Depending on the combination of the first and second detection results, an unused photoconductor unit is set in the apparatus main body 1, a used photoconductor unit is set, or a photoconductor unit is not set. A control device 10 is provided for determining whether or not the image formation is normal, in addition to controlling each unit related to image formation.

That is, in this embodiment, the control device 10
However, depending on the combination of the first and second detection results of the photo interrupter 5 (combination of ON / OFF), an unused photoconductor unit is set in the apparatus main body 1 or a used photoconductor unit is set. It functions as a photoreceptor attachment determination unit for determining whether the photoreceptor unit is set or not.

The detected member 52 provided on the photosensitive unit 2 is rotatably supported by a pin 6 fixed to a unit case 7 as shown in FIG. The body unit 2 is in the first position shown by a solid line, and the photosensitive unit 2 in use in which the photosensitive body 3 is set in the apparatus main body 1 and the photosensitive body 3 is rotated in the direction of arrow A, as shown in FIG. It is in position 2. Therefore, as for the photoreceptor unit 2, the one which has been used for maintenance or the like once removed from the apparatus
In the position.

The light-shielding portion 52a of the detected member 52 at the second position indicated by a virtual line in FIG.
As shown in FIG. 1, a photo-interrupter 5 shown in FIG. 1, which is a detecting means for detecting whether or not the detected member 52 is at a second position, is provided by arranging a detecting unit 5a in correspondence with Is fixed to the inner surface of the unit case 7.

Three belt-shaped photoconductors 3 (see FIG. 2)
The gear 51 is integrally fixed to a roller shaft 54 which is supported by the supporting rollers and is rotatable in the direction of arrow A in FIG. . Therefore, when the photoconductor 3 rotates, the support roller 50a and the other two support rollers rotate according to the moving speed of the photoconductor 3, and the gear 51 integrated with the support roller 50a also rotates in the direction of arrow B.

The detected member 52 has a gear portion 52b formed on the opposite side of the light shielding portion 52a, the gear portion 52b is formed by several gears, and teeth are provided on both sides in the circumferential direction of the gear portion 52b. The missing portions are respectively formed, and the engagement grooves 52c are formed on one side thereof. In the engagement groove 52c,
One end is fixed to the unit case 7 of the photoreceptor unit 2, and the engaging claw 8 a of the holding lever 8, which is biased by the spring property of the material itself so as to always contact the detected member 52, can be engaged. When the engaging claw 8a is engaged with the engaging groove 52c of the detected member 52, the detected member 52 is locked (FIG. 3) and its rotation is restricted.

When the detected member 52 rotates clockwise from the position shown by the solid line in FIG. 1 to the position shown in FIG. 5, the gear portion 52b engages with the gear 51. When the unused photoreceptor unit 2 in which the detected member 52 is located at the first position indicated by the solid line in FIG. 1 is set on the apparatus main body 1, the detected member 52 has a slope 9a as shown in FIG. A moving member 9 is provided in the apparatus main body 1 so that the gear member 52b contacts the gear portion 52b and the gear 51 shown in FIG. Note that the photoconductor unit 2 is also integrally formed with a cleaning device 15.

In this laser printer, the control device 10 shown in FIG. 1 executes the judgment and the processing at a predetermined timing according to the flowchart shown in FIG. That is, when the control device 10 starts the routine of FIG. 6, in step 1, the detection unit 5a of the photointerrupter 5
It is determined whether or not the light is shielded by the second light-shielding portion 52a to detect it (first detection), and if it is detected, the detected member 52 is moved to the second position as shown in FIG. Therefore, the process proceeds to step 2 to determine that the photoconductor unit 2 in use is set.

Further, the detected member 52
Is not detected, the detected member 52 is at the first position indicated by the solid line in FIG. 1 or the photoconductor unit 2 is not set in the apparatus main body 1, and the process proceeds to step 3 to control. The timer provided in the apparatus 10 is reset, and the timer is started in step 4, and in step 5, the photosensitive member 2 provided on the apparatus main body 1 side is reset.
A gear (not shown) for driving the motor is rotated for a predetermined time.

Then, in the next step 6, it is determined whether or not the timer started in step 4 has elapsed a predetermined time. Then, it is determined again whether the detector 5a of the photointerrupter 5 has detected the light-shielding portion 52a of the detected member 52 (second detection), and if it has been detected, the detected member 52a is detected. Is in the second position, it is determined in step 8 that an unused photoconductor unit is set, and the process is terminated. If the detected member 52 has not been detected in step 7, the process proceeds to step 9, where it is determined that the photoconductor unit has not been set, and the process ends.

Next, a case where an unused photoconductor unit is set in the apparatus main body 1, a case where a used photoconductor unit is set, and a case where no photoconductor unit is set will be described in detail. . First of all,
A case where an unused photoconductor unit is set in the apparatus main body 1 will be described.

In this case, as described above, the detected member 52 is at the first position shown by the solid line in FIG. The gear unit 52 is rotated in the direction of arrow E in contact with the moving member 9 shown in FIG.
b meshes with the gear 51. In this state, the holding lever 8
Is in contact with the toothless portion of the detected member 52, but is not locked in the engaging groove 52c yet, so that the detected member 52 is not locked.

In this state, when the routine shown in FIG. 6 starts, the process proceeds to step 3 because the photointerrupter 5 does not detect the detected member 52 in step 1, and resets the timer there and starts the timer in step 4. Then, in order to rotate the photoconductor driving gear in the next step 5, the driving system such as the support roller 50a in which the driving system gear is engaged with the gear rotates, whereby the photoconductor 2 is moved in the direction indicated by the arrow in FIG. It is rotated in the direction A shown.

When the photosensitive member 2 rotates, the gear 51 also rotates in the direction indicated by the arrow B in FIG. 5 together with the support roller 50a, so that the detected member 52 meshed with the gear portion 52b moves in the direction indicated by the arrow E. Rotate. And the gear portion 52
When the detected member 52 rotates to a position shown in FIG. 3 at which b does not mesh with the gear 51, the rotation is stopped and the engaging claw 8a of the holding lever 8 is fitted into the engaging groove 52c of the detected member 52. Therefore, it is locked in the second position as shown.

Next, in step 6 of FIG. 6, when it is determined that a predetermined time (set in advance) has elapsed from step 4, the process proceeds to step 7 and the second detection by the photo interrupter 5 is performed again. It is determined whether the detected member 52 is at the second position (the position shown in FIG. 3). However, since the detected member 52 has already been moved to the second position by the rotation of the photoconductor 2, the step is performed. Proceeding to 8, it is determined that an unused photoconductor unit has been set.

When the photoconductor unit 2 in use is set, the detected member 52 engages with the engaging claw 8a of the holding lever 8 in the engaging groove 52c as shown in FIG. And because it is in the second position,
In the determination of step 1 in FIG. 6, the determination of YES is made and the process proceeds to step 2, where it is determined that the photoconductor unit in use is set, and the process is terminated.

Therefore, in this case, the photosensitive member 3 described in Steps 5 and 7 is not rotated, and the second detection by the photo interrupter 5 is not performed. That is, the apparatus main body 1 does not need to perform those processes and determinations.
Can be determined as the photoconductor unit in use. Therefore, by not rotating the photoconductor 2 for the second detection as in this embodiment, the consumption (fatigue) of the photoconductor 2 can be suppressed accordingly.

When the photoconductor unit 2 is removed from the apparatus main body 1 for maintenance or the like, step 1
Since the photointerrupter 5 does not detect the detected member 52 in the determination of (3), the process proceeds to steps 3 → 4 → 5 to rotate the photoconductor driving gear (not shown).

However, since the photoreceptor unit 2 is not set in the apparatus main body 1, the gear for driving the photoreceptor idles for a predetermined time in this case. Then, it is determined in Step 6 that a predetermined time has elapsed, and the process proceeds to Step 7 where the second photo interrupter 5 again performs the second operation.
Although the photodetector 5 performs the second detection, the photointerrupter 5 does not detect the detected member 52 (NO determination), so that it is determined in step 9 that the photoconductor unit is not set, and the process ends.

As described above, in this embodiment, the control device 10 controls the first
If the detected member 52 is not at the second position in the second detection result and is in the second position in the second detection result in step 7, the unused photoconductor unit 2 is It is determined that it has been set to 1.

If the detected member 52 is at the second position as a result of the first detection, it is determined that the photosensitive unit 2 in use has been set in the apparatus main body 1. Further, if both the detected members 52 are not at the second position in the first and second detection results, it is determined that the photoconductor unit 2 is not set in the apparatus main body 1.

The first detection result indicates that the detected member 5
Even when 2 is in the second position, the photosensitive member 3 is rotated thereafter, and after a certain period of time, the second detection is performed again, and the detection result indicates that the detected member 52 is in the second position. In some cases, it may be determined that the photoconductor unit 2 in use is set in the apparatus main body 1. However, in this case, the photoconductor 3 is unnecessarily rotated for the second detection.
It is desirable to omit the second detection as in the above-described embodiment.

As described above, according to this embodiment, only one photo-interrupter 5 is provided, so that the first detection detects whether or not the detected member 52 is at the second position. The photoreceptor 3 is rotated later, and after a certain period of time, the same detection is performed again for the second time, so that not only the photoreceptor unit 2 is simply mounted on the apparatus main body 1 but also that the photoreceptor unit 2 is mounted. It can also be determined whether the photoconductor unit 2 is unused or in use.

Therefore, when an unused photoreceptor unit 2 is set, the counting of the rotation time of the photoreceptor 3 is started at the time when it is determined that the photoreceptor unit 2 has been inserted. When the count value reaches the end of the service life, a display or the like indicating the replacement time is displayed, so that the photosensitive member can be efficiently replaced.

Therefore, recently, not only a limited number of people operate the printer or the like, but an unspecified number of people often operate the printer, and it is important to improve the operability of the machine correspondingly. The number of various automatic detection means increases because the number of things that must be automatically performed in the device increases, which increases the price of the entire device. Although there is a tendency, according to this embodiment, whether or not the photoconductor unit 2 is set in the apparatus main body 1 by one photointerrupter (detection means) 5 and whether or not an unused photoconductor unit is set are determined. Therefore, if the counting of the rotation time of the photoconductor 3 is started based on the signal, the replacement time of the photoconductor unit can be automatically set without increasing the number of sensors. Good device operability which can inform the can be provided at low cost.

In the above embodiment, the timing of starting the flow chart of FIG. 6 and performing the first detection is determined when the power of the apparatus is turned on or the apparatus main body 1 is turned on.
Is performed when the openable / closable covers provided at the various locations are closed, the frequency of rotating the photoconductor 3 for determining the mounting of the photoconductor unit 2 is reduced, and the Since unnecessary rotation can be eliminated, the photosensitive member 3
Consumption (fatigue) can be suppressed.

Particularly, if the first detection by the photo interrupter 5 is performed only when the cover that is opened and closed when the photosensitive unit 2 is replaced among the covers is opened and then closed, When a cover other than the cover that is opened and closed when the unit 2 is replaced is opened and closed by jam processing or the like, the detection of the detected member 52 is not performed, and the cover that can be opened and closed when the photosensitive unit 2 is replaced is opened and then closed. Since the detection is performed only at the time, the unnecessary rotation of the photoconductor 3 is further eliminated, and the fatigue of the photoconductor 3 can be prevented.

In the above embodiment, the photo interrupter 5 is used as a detecting means for detecting whether the detected member 52 is at the second position or not at a predetermined position. A reflection type photo sensor or the like may be used. Also, in FIG.
Is provided on the back side of the photoreceptor unit 2, and the photo interrupter 5 is fixedly disposed on the side of the apparatus main body 1 so as to correspond thereto,
If the mounting posture of the photo-interrupter 5 and the shape of the detection target member 52 do not affect the attachment / detachment operation of the photoreceptor unit 2, the photo-interrupter 5 does not need to be mounted for each photoreceptor unit, so that it is inexpensive. become.

[0050]

As described above, according to the present invention, it is determined whether an unused photoconductor unit is set in the apparatus main body according to the combination of the first and second detection results detected by the detecting means. It is possible to determine whether the photoconductor unit inside is set or the photoconductor unit is not set.When it is determined that an unused photoconductor unit is set, the rotation time of the photoconductor is determined. And so on, the photoconductor can be efficiently replaced when the photoconductor reaches the end of its life based on the count value. Since the detecting means is used for detecting whether or not the photoreceptor unit is set in the apparatus main body and whether or not the photoreceptor unit is unused, the detecting means is provided individually. The device can be made cheaper than in the case.

In addition to the judgment based on the combination of the first and second detection results by the detecting means, if the detected member is at the second position in the first detection result, the photosensitive unit in use is used. If the photoconductor mounting discriminating means for judging that the photoconductor unit is set is provided, the photoconductor unit in use is taken out once at the time of maintenance or the like, and when the photoconductor unit is set again in the apparatus main body, the first detection is performed. Since it is determined from the result that the detected member is at the second position, it is determined that the photoconductor unit in use is set.
The consumption (fatigue) of the photoconductor can be reduced by not having to rotate the photoconductor for the second detection thereafter.

Further, when the power of the apparatus is turned on or when the cover of the apparatus main body is closed, the first detection by the detecting means is performed, and the cover which is opened and closed when the photosensitive unit is replaced is provided. If the first detection is performed by the detecting means only when the photoconductor is opened and then closed, the frequency of rotation of the photoconductor for determining the mounting of the photoconductor can be reduced. Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a main part of a photoconductor unit that can be set in an apparatus main body of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an overall configuration diagram showing a laser printer as the image forming apparatus.

FIG. 3 is a schematic diagram showing a state where a detection target member 52 provided in the photoconductor unit of FIG. 1 is at a second position.

FIG. 4 is a perspective view showing the vicinity of the photosensitive member unit where a detected member 52 is provided.

FIG. 5 is a schematic diagram showing a state where a gear portion 52b of a detected member 52 and a gear 51 are engaged when an unused photoconductor unit is set in the apparatus main body.

FIG. 6 is a flowchart showing a determination and a process performed by a control device 10 of FIG. 1;

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Photoreceptor unit 3 Photoreceptor 5 Photointerrupter (detection means) 7 Unit case 8 Holding lever 10 Control device 50a Support roller 51 Gear 52 Detected member

Claims (4)

(57) [Claims] A detecting member that is at a first position in an unused state and moves to a second position when the photosensitive member is set and rotated in the apparatus main body; A detachable photoreceptor unit, detection means for detecting at a predetermined position whether the detected member is at the second position, and first detection at predetermined timing by the detection means; After that, the photoconductor is rotated, and after a lapse of a predetermined time, the detection unit performs the second detection again,
Depending on the combination of the first and second detection results, an unused photoconductor unit, a used photoconductor unit is set, or a photoconductor unit is not set in the apparatus main body. An image forming apparatus provided with a photoreceptor mounting determination unit for determining whether the image forming apparatus is mounted on the image forming apparatus. A detecting member which is at a first position in an unused state and which moves to a second position when the photosensitive member is set and is rotated in the apparatus main body; A detachable photoreceptor unit, detection means for detecting at a predetermined position whether the detected member is at the second position, and first detection at predetermined timing by the detection means; If the detected member is not at the second position according to the detection result, the photosensitive member is rotated, and after a certain period of time, the detection unit performs the second detection again, and the first and second detections are performed. Based on the combination of the results, it is determined whether an unused photoconductor unit is set or the photoconductor unit is not set. If the detected member is at the second position based on the first detection result, Photoconductor unit in use An image forming apparatus provided with a photoreceptor mounting determining means for determining that the image is set. 3. The image forming apparatus according to claim 1, wherein the first detection is performed by the detecting means when the power of the apparatus is turned on or when the cover of the apparatus main body is closed. Image forming apparatus. 4. The image forming apparatus according to claim 1, wherein the first detection is performed by the detection unit only when a cover that is opened and closed when the photoconductor unit is replaced is opened and then closed. An image forming apparatus characterized by performing the following.