JP2003248374A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an image defect or jamming from occurring because transfer material floats from a carrying reference surface after the transfer material to which a toner image has been transferred is separated from the surface of a photoreceptor drum. <P>SOLUTION: A toner image is formed on the photoreceptor drum 10 and transferred to the transfer material P by a transfer electrifier. By applying a current to a separation electrifier 21, the transfer material P to which the toner image has been transferred is separated from the surface of the drum 10. The floating amount of the separated transfer material P from the carrying reference surface H is detected by a reflection type optical sensor 17. When the floating amount is not normal (for example, it is larger than 1 mm being a reference value), the current applied to the electrifier 21 is changed to make the floating amount normal in the case of separating the transfer material P from the drum 10. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer or a fax machine.

[0002]

2. Description of the Related Art Conventionally, copying machines, printers, fax machines,
In an image forming apparatus such as an inkjet printer, a transfer material (recording medium) such as paper, OHP film, plate or cloth
There is known a separation device that separates the.

The first separation device, as shown in FIG.
A separation charger 21 that separates the transfer material P from the photosensitive drum (image carrier) 10. The transfer material P is a paper feeding unit (not shown)
From the transfer charger (not shown),
The toner image on the photosensitive drum (image carrier) 11 is transferred. The transfer material P after the toner image transfer is electrostatically separated from the photosensitive drum 10 by applying a current to the separation charger 21.

Here, the operation of the separation unit will be described in detail by taking the above-mentioned first separation device as an example.

In FIG. 12, the toner image formed on the photosensitive drum 10 is transferred to the transfer material P at a transfer portion between the photosensitive drum 10 and the transfer charger 20, and then a current is supplied to the separation charger 21. Is applied to separate from the surface of the photosensitive drum 10.

If this separation is not carried out well, the transfer material P moves while being in contact with the photosensitive drum 10, so that the transfer material P rushes into another member (for example, the cleaning device 23) disposed opposite to the surface of the photosensitive drum 10. , Other members may be damaged.

Further, even if the transfer material P is not damaged,
May be conveyed while contacting the separation claw 22 provided so as not to damage the cleaning device 23. In this case, a separation claw mark is generated on the image, resulting in an image defect.

In order to prevent this image defect, a transfer material detecting means, for example, an optical sensor 17 is provided in the conveying portion after the separating portion, and after a lapse of a prescribed time determined in the design stage, for example, the image forming apparatus shown in FIG. Then, the transfer materials P sent one by one from the paper feeding section are temporarily stopped by a registration roller (not shown), and after the image forming signal is issued, the registration rollers rotate to supply the transfer material P to the transfer section 15. , As shown in FIG.
After 500 ms (reference numeral b in FIG. 4) from the generation of an operation signal (reference numeral a in FIG. 4) of the registration roller clutch (not shown) for operating the registration roller 19, the state of the optical sensor 17 is High (reference numeral d in FIG. 4). Whether or not it is Low (reference numeral e in FIG. 4). For example, if Low indicates that there is no transfer material P, and if the state of the optical sensor 17 is Low, then the transfer material P is transferred to the optical sensor 17 for some reason. Since it did not arrive, it detected a jam and stopped the image forming apparatus.

Further, in the image forming apparatus of FIG. 1, the current value applied to the separation charger 21 used for separating the transfer material P from the photosensitive drum 10 is determined by the atmosphere (temperature, humidity) in which the image forming apparatus is placed. ) Was determined and the current value was changed according to the atmosphere, but the current value was constant in the atmosphere.

Further, there is a device for cleaning the separation charging device 21 which is used for separating the transfer material P from the photosensitive drum 10, but the cleaning member is operated at a certain time after a certain number of sheets have been passed or a certain time after the power is turned on. It was regular as later.

[0011]

In the above image forming apparatus, when the transfer material P is separated from the photosensitive drum 10,
When the current applied to the separation charging device 21 is not appropriate, the transfer material P is lifted from the transfer reference surface H and is transferred, and the image portion on the transfer material P contacts the separation claw 22 to form an image. A defect may occur, or the transfer material P may enter between the separation claw 22 and the photosensitive drum 10 to cause a jam.

Further, in the same atmosphere, the separation charger 21
Since the current value applied to is almost constant is fixed, the current value may not be appropriate for separating the transfer material P from these depending on the state of the photosensitive drum 11, and in this case also, separation failure may occur. As a result, the above-mentioned image defect and jam occurred.

Further, when the number of sheets passed (the number of formed images) becomes large and the separation charging device 21 becomes dirty, it becomes impossible to apply a proper separation current to the transfer material P, resulting in a separation failure, which also causes an image failure. There was a jam.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image forming apparatus capable of always exhibiting good separation performance.

[0015]

The invention according to claim 1 is
In an image forming apparatus that transfers a toner image from an image bearing member that carries a toner image on a surface to a transfer material, and separates the transfer material after the toner image transfer from the image bearing member by a separator, Detecting means for detecting the amount of floating from the conveyance reference surface, based on the detection result of the detecting means, control means for changing at least one of the condition at the time of transfer material separation and the condition at the time of toner image development, Is provided.

According to a second aspect of the present invention, an image in which a toner image is transferred from an image carrier having a toner image on its surface to a transfer material, and the transfer material after the toner image transfer is separated from the image carrier by a separator. In the forming device, the transfer material after separation,
Detecting means for detecting the floating width from the conveyance reference surface, based on the detection result of the detecting means, a control means for changing at least one of the condition during transfer material separation and the condition during toner image development, Is provided.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the detecting unit also serves as a separation jam detecting unit.

The invention according to claim 4 relates to claims 1 to 3.
The image forming apparatus described in any one of 1 to 3 above, wherein the detection unit is a reflection type optical sensor.

The invention according to claim 5 relates to claims 1 to 4.
In the image forming apparatus described in any one of 1 above, the condition at the time of separating the transfer material is a voltage or a current applied to the separating device.

The invention according to claim 6 relates to claims 1 to 4.
In the image forming apparatus described in any one of 1) to 1), the condition for developing the toner image is a developing bias applied to a developing unit when developing the toner image.

The invention according to claim 7 relates to claims 1 to 6.
The image forming apparatus according to any one of claims 1 to 3, further comprising a cleaning member that cleans the separation unit, and the control unit cleans the separation unit by the cleaning member based on a detection result of the detection unit. It is characterized by

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The same reference numerals in the drawings denote the same configurations or operations, and repeated description thereof will be omitted as appropriate.

<First Embodiment> FIG. 1 shows an example of an image forming apparatus according to the present invention. The image forming apparatus shown in FIG.
FIG. 1 is an electrophotographic laser printer, which is a vertical sectional view schematically showing the schematic configuration thereof.

The image forming apparatus shown in the figure comprises a drum type electrophotographic photosensitive member (hereinafter referred to as "photosensitive drum") 10 as an image bearing member. In the present embodiment, the photosensitive drum 10 uses a-Si (amorphous silicon) having a positive charging characteristic.

The photosensitive drum 10 is rotationally driven in the clockwise direction in the figure by driving means (not shown), and the surface thereof is uniformly charged to a predetermined polarity and potential by a primary charger (charging means) 11. The surface of the photosensitive drum 10 after being charged is irradiated with laser light according to image information by a laser scanner as an exposure device (exposure means) 12 to form an electrostatic latent image. It should be noted that this image information is obtained by reading the document image by the reader unit 18.

The electrostatic latent image formed on the surface of the photosensitive drum 10 is developed (developed) as a toner image with toner attached by a developing device (developing means) 13.

On the other hand, a paper feed cassette is arranged in the lower part of the main body of the image forming apparatus (not shown), and the transfer materials P (for example, paper, transparent film) are stored in a laminated state in the cassette. . The transfer material P is fed to the registration roller pair 19 one by one from the uppermost one by the paper feed roller 14 rotating counterclockwise in FIG.
The transfer material P has a pair of registration rollers 19 whose ends are stopped.
The sheet is brought into contact with the nip portion of No. 3, a predetermined amount of loop is formed to correct the skew, and then stopped. The transfer material whose skew has been corrected is supplied to the transfer portion 15 between the photosensitive drum 10 and the transfer charger 20 by the registration roller pair 19 which starts rotating at a predetermined timing.

When the transfer material P passes through the transfer portion 15, the above-mentioned toner image formed on the photosensitive drum 1 is transferred by the transfer charger 20. The transfer material P at the time of transferring the toner image is electrostatically attracted to the photosensitive drum 10, but after the toner image is transferred, it is separated from the photosensitive drum 10 by the separation charger 21 and the separation claw 22.

The transfer material P normally separated from the photosensitive drum 10 reaches the reflection type optical sensor (post-separation sensor) 17 at regular timing. Further, the toner image is conveyed to the fixing device 16 and heated and pressurized there, and the unfixed toner image is fixed on the surface of the transfer material P. The transfer material P on which the toner image has been fixed is discharged to a paper discharge tray (not shown), which completes the image formation. On the other hand, the photosensitive drum 10 after the toner image transfer is subjected to the next image formation by removing the toner (residual toner) remaining on the surface without being transferred to the transfer material P by the cleaning blade of the cleaning device 23.

In the above-mentioned image forming apparatus, a reflection type optical sensor 17 is arranged in the transfer path of the transfer material P, on the downstream side of the separation charger 21 along the transfer direction of the transfer material P. There is. The optical sensor 17 detects the floating amount of the transfer material P from the transport reference surface (the floating amount will be described later), and based on the detection result, in the embodiment of the present embodiment, the separation charger. The current value applied to 21 is changed by the control means (not shown).

The operation for optimizing the floating amount will be described below.
This will be described with reference to the flowchart of FIG.

After the image formation start (copy start) is started (S1), the floating amount of the transfer material P is measured. As shown in FIG. 3, the floating amount refers to the distance from the conveyance reference surface H to the transfer material P, and as shown in FIG. 4, it is calculated by using the clutch ON signal of the registration roller pair 19 as the reference signal a. The floating height of the transfer material P from the conveyance reference surface H is obtained 5 ms after the obtained time point b (500 ms in the example of FIG. 4) when the front end of the recording material P passes the optical sensor 17.
That is, when the distance from the registration roller pair 19 to the optical sensor 17 is A and the transport speed of the transfer material P is v,
The floating amount after (A / v) +5 ms is detected from the above-mentioned clutch ON signal.

Here, when an appropriate current for separating the transfer material P from the photosensitive drum 10 is applied, the transfer material P is
The floating amount is 0 to 1 mm, but when an appropriate current is not applied, the transfer material P floats 1 mm or more from the transport path.

Therefore, when the floating amount of the transfer material P is 0 to 1 mm (“Y” in S3 of FIG. 2), the separation performance is normal, so the conditions for separation are left unchanged. On the other hand, 1
If it is ˜3 mm (“N” in S3, “Y” in S4), the separation performance is not sufficient, so that the current applied to the separation charger 21 is −10 μ for the purpose of normalizing the separation performance.
A is changed (S5). This is because it is known that when the photosensitive drum 10 is a-Si (amorphous silicon) having a positive charging characteristic, it is easy to separate when the current is changed to the negative side. When the photosensitive drum 10 is an OPC (organic optical semiconductor) having a negative charging polarity, it may be changed to the positive side.

As shown in FIG. 5, the transfer material P (paper) is 1 m.
It floats when m is deviated from the proper value by 12 μA.
Here, by changing the separation current by -10 μA, the current value becomes an appropriate value +2 μA, and the floating amount of the transfer material P becomes 0.
It can be reduced to about 2 mm.

Returning to FIG. 2, when the floating amount of the transfer material P is 3 mm or more (“N” in S4, “Y” in S6, S7),
Since an abnormality of the separation charger 21 is also considered, the separation charger 21 is cleaned by a separation charger cleaning means (not shown) (S
8: For example, the foreign matter adhering to the discharge wire of the separation charger 21 is wiped off. ), Normalize the separation performance. Further, after the separation charger 21 is cleaned, when the paper is passed again, the transfer material P
When the floating width of is 3 mm or more (“N” in S7),
On the operation panel (not shown) of the main body of the image forming apparatus, for example, "the ability of the separation charger is deteriorated" is displayed (S
9) Get a service call. As a result, the service person can know the abnormality of the separation charger 21, and can replace the separation charger to obtain normal separation performance.

The above-mentioned reflection type optical sensor 17 also serves as a separation jam detecting means, and the clutch ON signal of the registration roller pair 19 is used as a reference signal, and {registration roller pair 1
It is normal when the optical sensor 17 detects the transfer material P (d in FIG. 4) at the timing of (9) distance between optical sensor 17 (x) / conveyance speed of transfer material P (v)} + jam margin. On the other hand, if it cannot be detected (e in FIG. 4),
The separation jam is set, the operation of the image forming apparatus is stopped, the user is notified of the jam, and the jam processing is prompted.

<Second Embodiment> Primary charger 1 shown in FIG.
After the potential of the surface of the photosensitive drum 10 is made constant by 1, an electrostatic latent image is formed by the exposure device 12, and toner is attached to the electrostatic latent image by the developing device 13 to develop it as a toner image. 6, it is known that the higher the density of the toner image on the photosensitive drum 10, the better the separability of the transfer material P at the time of separation.
In FIG. 6, the separation performance is defined as the floating amount of the transfer material (recording medium), and the larger the floating amount, the worse the separation performance.

In the present embodiment, in the image forming apparatus for transferring the toner image developed on the photosensitive drum 10 to the transfer material P in the transfer portion 15, the floating amount of the transfer material P detected by the optical sensor 17 is detected. The developing bias applied to the developing device 13 is changed. Specifically, when the separation performance is poor and the floating amount is large, the fog is actively generated to increase the density of the toner image on the photosensitive drum 10, thereby improving the separation performance and increasing the floating amount. To reduce.

The details will be described below.

The optical sensor 17 shown in FIG. 1 measures the floating amount of the transfer material P from the conveyance reference surface. When an appropriate current for separating the paper from the photosensitive drum 10 is applied, the floating amount of the transfer material P is 0 to 1 mm, but when the appropriate current is not applied, the transfer material P is the transport reference. Lifted by 1 mm or more from the surface.

When the floating amount of the transfer material P is 0 to 1 mm, the separation performance is normal and the image forming conditions are not changed and the image formation is continued. On the contrary,
When the floating amount is 1 to 3 mm, the separation performance is not sufficient, and therefore the DC component of the developing bias is adjusted so that toner that cannot be visually observed is excessively placed on the surface of the photosensitive drum 10 for the purpose of normalizing the separation performance. Change. That is, the fog state is positively set.

The DC component of the developing bias is the primary charger 1
It is set to an intermediate value between the dark portion drum potential applied by 1 and the light portion drum potential exposed by the exposure device 12, and the toner is developed only on the portion of the light portion drum potential. Fog is zero in this state. Here, when the DC component of the developing bias is swung to the dark portion drum potential side from the set value, the toner is also developed on the portion of the dark portion drum potential and fog occurs. Generally, when fogging occurs, the output image becomes black and the image becomes defective. Therefore, the developing bias is set so that the fogging becomes zero.

However, since it is known that the separation performance improves when the fog occurs, the phenomenon bias value at which the fog occurs is positively controlled here for the purpose of improving the separation performance. However, if the developing bias is largely shaken to the potential of the dark drum, the fog may become visible and the image may be defective. Therefore, it is necessary to obtain the fog (density 0 to 0.2) which cannot be visually observed. The developing bias is changed by -80A. As shown in FIG. 7, it is necessary to change −80 A to obtain an image fog density of about 0.2.

As can be seen from FIG. 6, when the image density changes from 0 to 0.2, it can be expected that the floating amount of the transfer material P will be reduced by about 1.7 mm, thereby improving the separation performance. it can.

Also in the present embodiment, when the floating amount of the transfer material P is 3 mm or more, the separation charger 21 may be abnormal.

Therefore, as in the first embodiment, the separation charging device cleaning means (not shown) cleans the separation charging device 21 to normalize the separation performance. Further, when the separation charger 21 is cleaned and then passed again, the floating width of the transfer material P is 3 mm again.
In the case of the above, the operation panel (not shown) of the image forming apparatus main body displays, for example, "the capability of the separation charger is deteriorated" and asks for a service call. As a result, the service person can know the abnormality of the separation charger 21, and can replace the separation charger to obtain normal separation performance.

<Third Embodiment> In the present embodiment, as shown in FIG. 8, the optical sensor 17 does not detect the transfer material P when the transfer material P is lifted by 1 mm or more from the conveyance reference surface. To do. Here, the sensor ON time is measured using the clutch ON signal of the registration roller pair 19 as a reference signal. Here, when the transfer material P does not float by 1 mm or more,
The sensor passage time T is the distance (x) between the registration roller pair 19 and the optical sensor 17 / the transport speed (v) of the transfer material P.

However, when the transfer material P floats by 1 mm or more and is conveyed, the sensor passage time becomes a value T'which is larger than T. When {(T′−T) × v} is calculated here, FIG.
The floating width of the transfer material P shown in can be measured. Here, the larger the floating width of the transfer material P, the more likely there is a jam on the separation claw or an image defect, and the separation performance deteriorates.

Therefore, the frequency at each sensor passage timing is calculated for each predetermined number of sheets, and the total value (HA) of T (0 to ∞) in {(T′−T) × v} × (frequency / number of sheets) is calculated.
Value) is calculated. The larger the HA value, the larger the floating width of the transfer material P. That is, the separation failure rate is large. Therefore, a threshold value S for the HA value is provided, and when the HA value exceeds a predetermined threshold value S, the current value applied to the separation charger 21 is changed.

Here, FIG. 9 shows the relationship between the floating width of the transfer material P when the separation performance is normal and when the separation performance is deteriorated, for comparison after passing 100 sheets. The horizontal axis represents the floating width of the transfer material P (paper), and the vertical axis represents the frequency. Here, the peak of “a” in the figure is the peak after normal separation, and the floating width of the transfer material P is 0 mm. On the other hand, the crest of b in the figure is a crest generated due to the deterioration of the separation performance, and the floating width of the transfer material P is a value greater than 0, and the floating width increases toward the right. Looking at the HA value, it is 0 when the separation performance is normal, but it is 0.5 when it is slightly decreased, and it is 46.1 when it is further decreased. When the HA value is about 0.5, the separation performance does not deteriorate so much, but there is no problem, but 46.1
When it reaches a certain level, it is necessary to improve the separation performance.
Therefore, the threshold value S of the HA value is set to, for example, 10
When it exceeds the value, the current value applied to the separation charger 21 is -10 μ
A change. By doing so, it can be expected that the peak of the separation performance drop in FIG. 9 will change to the peak of the normal separation performance, and the separation performance can be improved.

In this embodiment, since the HA value is calculated and the separation performance is deteriorated when the HA value is exceeded, the operation for improving the separation performance is performed.
It may be configured such that the operation is performed when there are m or more sheets.

In the first, second, and third embodiments described above,
The case where the transfer material P is separated from the photosensitive drum 10 has been described as an example, but the present invention is not limited to this, and the case where the transfer material P is separated from the transport belt 24 shown in FIG. Even when the intermediate transfer belt 26 is separated from the intermediate transfer belt 26 shown in the figure, the basic structure can be applied as it is. Reference numeral 25 in FIG. 10 indicates an adsorption charger for adsorbing the transfer material on the surface of the conveyor belt 24,
Further, reference numeral 26 in FIG. 11 indicates the intermediate transfer belt 26.

In the example shown in FIG. 10, a pair of registration rollers 1
The transfer material supplied by 9 is attracted to the conveyor belt 24 by the adsorption charger 25 and conveyed by the counterclockwise rotation of the conveyor belt 24 in the figure. Photosensitive drum 1
The toner image formed on the image transfer medium 0 is transferred to the transfer material by the transfer charger 20. The transfer material after the toner image transfer is
It is separated from the conveyor belt 24 by the separation charger 21,
The above-mentioned floating amount and floating width are detected by the optical sensor 17. Then, based on the detection result, for example, the current applied to the separation charger 21 when the transfer material is separated is changed.

In the example shown in FIG. 11, four developing devices 13 are provided, and yellow, magenta, cyan, and black toner images are sequentially formed on the photosensitive drum 10 by these developing devices 13, and an intermediate image is formed. Primary transfer is sequentially performed on the transfer belt 26, and the intermediate transfer belt 26 superimposes them. The four color toner images on the intermediate transfer belt 26 are
The transfer charging device (not shown) collectively secondarily transfers the transfer material P onto the transfer material P, and then the separation charging device 21 separates the intermediate transfer belt 26. The optical sensor 17 detects the floating amount and the floating width. It Then, based on the detection result, for example, when the transfer material P is separated, the separation charger 21
Change the current applied to. In this example, the intermediate transfer belt 26 serves as an image carrier that carries a toner image.

The image forming apparatus shown in FIGS. 10 and 11 also has the same effect as that of the above-described embodiment.

Further, in the case where the image forming apparatus is an ink jet printer and the transfer material is paper, a separating device for separating the transfer material from a head (not shown) for ejecting ink onto the transfer material to form an image is also used. The present invention can be applied. That is, the floating amount and the floating width of the transfer material after separation are detected, and the current applied to the separation charger is changed at the time of separation based on the detection result.

[0058]

As described above, according to the present invention,
The posture of the transfer material after separation is detected by detecting the floating amount and the floating width of the transfer material after separation of the transfer material, and changing the conditions at the time of separation and the conditions at the time of development by the control means based on the detection result. Therefore, it is possible to prevent an image defect in which an image is rubbed by the separation claw and a jam caused by the transfer material invading between the separation claw and the image carrier, for example. .

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a schematic configuration of an image forming apparatus according to the present invention.

FIG. 2 is a flowchart showing a flow for controlling a floating amount of a transfer material after separation.

FIG. 3 is a diagram illustrating a floating amount of a transfer material.

FIG. 4 is a time chart explaining the timing for detecting the floating amount of the transfer material.

FIG. 5 is a diagram showing the relationship between the amount of change in separation current from an appropriate value and the amount of floating.

FIG. 6 is a diagram showing a relationship between an image density and a transfer material floating amount (recording medium floating amount).

FIG. 7: Image fog density and developing bias (DC component)
It is a figure which shows the relationship with the amount of change.

FIG. 8 is a diagram illustrating a floating width of a transfer material.

FIG. 9 is a diagram showing the relationship between the floating width of a transfer material (paper) and the frequency.

FIG. 10 is a diagram schematically illustrating a schematic configuration of an image forming apparatus that separates a transfer material after a toner image is transferred from a conveyor belt.

FIG. 11 is a diagram schematically illustrating a schematic configuration of an image forming apparatus that separates a transfer material after a toner image is transferred from an intermediate transfer belt.

FIG. 12 is a diagram schematically illustrating a schematic configuration of a conventional image forming apparatus that separates a transfer material after a toner image is transferred from a photosensitive drum.

[Explanation of symbols]

10 Image carrier (photosensitive drum) 13 Developing means (developing device) 17 Detection means (optical sensor) 21 Separation device (separation charger) 26 Image carrier (intermediate transfer belt) H transport reference plane P transfer material

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 21/00 370 G03G 21/00 370 F term (reference) 2H027 DA04 DC14 DC16 DE02 DE07 DE09 EA05 EA10 EA15 EA18 EC06 EC09 EC20 ED09 ED15 ED24 ED26 ED27 EE07 2H072 AA02 AA09 AA16 AA24 AB19 2H073 AA01 BA01 BA13 BA21 2H200 GA18 GA23 GA44 HA12 HB03 HB26 JA01 KA02 KA07 KA14 KA29 KA30 LB01 PB15 PA02 PA10

Claims (7)

[Claims] 1. An image forming apparatus in which a toner image is transferred from an image carrier carrying a toner image on a surface to a transfer material, and the transfer material after the toner image transfer is separated from the image carrier by a separating device. Detecting means for detecting the floating amount of the transfer material from the conveyance reference surface, and based on the detection result of the detecting means, at least one of the condition for separating the transfer material and the condition for developing the toner image is changed. An image forming apparatus, comprising: 2. An image forming apparatus in which a toner image is transferred from an image carrier carrying a toner image on a surface to a transfer material, and the transfer material after the toner image transfer is separated from the image carrier by a separating device. Detecting means for detecting the floating width of the transfer material from the conveyance reference surface, and based on the detection result of the detecting means, at least one of the transfer material separating condition and the toner image developing condition is changed. An image forming apparatus, comprising: 3. The image forming apparatus according to claim 1, wherein the detection unit also serves as a separation jam detection unit. 4. The image forming apparatus according to claim 1, wherein the detection unit is a reflection type optical sensor. 5. The image forming apparatus according to claim 1, wherein the condition at the time of separating the transfer material is a voltage or a current applied to the separating device. 6. The image forming apparatus according to claim 1, wherein the condition for developing the toner image is a developing bias applied to a developing unit when the toner image is developed. . 7. A cleaning member for cleaning the separating means is provided, wherein the control means is based on a detection result of the detection means.
The image forming apparatus according to claim 1, wherein the separating member is cleaned by the cleaning member.