JP2002021952A - Endless belt driving device and image forming apparatus having the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endless belt driving device adapted to determine the life of an endless belt-like member according to the elastic wave vibration showing the occurrence of very small deformation breakage in the interior and an image forming apparatus having the device. SOLUTION: A rubber plate 38a of a cleaning device 38 for removing dirt such as surplus toner or the like adhering to a transfer belt 30 is in contact with the transfer belt 30. With the movement of the transfer belt, very slight vibration is caused in the rubber plate 38a. Mechanical stress due to the very slight vibration of the rubber blade 38a is applied to the transfer belt 30, and when deformation breakage is caused in the transfer belt 30, very small elastic wave vibration is caused. Therefore, a detecting device 40 is brought into contact with a part of the transfer belt 30 to detect the very small elastic wave vibration, thereby determining the life of the transfer belt 30, and necessary measures are taken, for example, a warning is displayed or the device is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless belt driving device, and more particularly to an image forming apparatus such as a copying machine, a printer, a facsimile, etc., which includes an endless belt-shaped member as a constituent member.

[0002]

2. Description of the Related Art Many image forming apparatuses of an electrophotographic type or the like include an endless belt-like member as a constituent member. That is, for example, in a tandem type color copying machine, four image forming units loaded with toners of yellow, magenta, cyan, and black are arranged in a line, and four transfer belts as endless belt-shaped members are provided. Is configured to move along the image forming unit. Then, the toner images of each color of yellow, magenta, cyan, and black formed on the photosensitive drum of each image forming unit are superimposed and transferred on the transfer belt to form a color toner image. Next, the formed color toner image is transferred onto a recording medium and subjected to a heat fixing process by a fixing device to obtain a color image.

Further, a fixing device comprising an endless belt-shaped member has also been proposed (for example, see Japanese Patent Application Laid-Open No. H10-1).
Further, an endless belt-shaped photoconductor, a charging device, an endless belt-shaped cleaner, and the like have been proposed. In addition, an endless belt-shaped member is also used for an automatic document feeder and a transfer of a recording medium.

As described above, many endless belt-shaped members are used as constituent members in an image forming apparatus, and the life thereof has been extended in recent years, so that it can withstand millions of prints. The endless belt-shaped member is erroneously scratched, for example, when a jam occurring in the paper feeding / conveying mechanism is processed or the image forming unit is replaced, or a defect of the material, such as a pinhole, is visually observed. It is inevitable that the endless belt-shaped member, which cannot be found in the inspection, is damaged or broken due to cracking, cutting, or the like based on the scratch.

[0005] Even if the endless belt-shaped member is not damaged or broken, there is no such thing as dirt and abrasion due to long-time use, changes in electrical resistance due to repeated application and discharge of high voltage, and the like.
Deterioration of the endless belt-like member due to repeated use for a long period of time is inevitable.

As a countermeasure for this, there has been proposed an apparatus which detects and displays the state of deterioration of the endless belt-shaped member. That is,
Japanese Patent Application Laid-Open No. 11-231672 discloses a configuration in which the state of dirt on the surface of a transfer belt is determined, and based on the result, the state of dirt, life, timing for performing maintenance, and the like are displayed on a display unit of an operation panel. Is disclosed.

Japanese Patent Application Laid-Open No. H11-143252 discloses a structure in which a paint is contained in a transfer belt or a paint is applied so that scratches or peeling of the surface layer can be easily found by visual inspection. I have.

Japanese Patent Application Laid-Open No. 11-84900 discloses a counter for accumulating and counting the number of rotations of a transfer belt. When the counter reaches a predetermined count value, the end of life is displayed or the image forming operation is stopped. There is disclosed a configuration for causing this to occur.

Japanese Patent Application Laid-Open No. 9-31523 discloses a technique in which a voltage applying roller and an opposing roller are arranged with a transfer belt interposed therebetween, and a pinhole or breakage of the transfer belt is determined based on a current flowing from the voltage applying roller to the opposing roller. A configuration for detecting is disclosed.

[0010]

However, the conventional method for detecting the defect and the life of the endless belt-shaped member as described above has the following disadvantages. That is, in the image forming apparatus, a small amount of toner adhering to the periphery of the image forming unit and the transfer belt adheres to the transfer belt even when no charge is applied to the transfer belt which is an endless belt-like member, and the image is fogged. Symptoms may occur. In order to remove such fogging toner, there is a cleaning device provided with a cleaning member that comes into mechanical contact with the transfer belt. However, in this device, the transfer belt and the cleaning device rub against each other. Occurs.

In a cleaning apparatus which generates an electric field having a polarity opposite to that of the fog toner by bringing the charge applying roller into contact with the transfer belt in order to remove the fog toner, the electrical characteristics of the transfer belt are changed. In some cases, the toner image cannot be transferred from the image forming unit due to the high resistance of the image forming unit.

For this reason, when the life is determined by detecting the state of the surface of the endless belt-shaped member, it becomes difficult to discriminate between the adhesion of the fog toner and the adhesion of the dirt, and it is erroneously determined that the life has expired. There are inconveniences such as difficulty in distinguishing the adhesion of the fogging toner from the rubbing streaks generated on the transfer belt, or the inability to determine the deterioration of the electrical characteristics of the endless belt-shaped member.

Further, in the method of detecting the state of the surface of the endless belt-shaped member to determine the life, if the detection device is not a detection device capable of detecting the surface state of the entire surface of the endless belt-shaped member, the undetectable portion may be stained. I can't deal with it.
A detection device capable of detecting the surface state of the entire surface of the endless belt-shaped member has a detection sensor arranged at least on the entire surface in a direction perpendicular to the moving direction of the endless belt-shaped member, and driving the endless belt-shaped member to detect the surface state Since the state must be detected, the size of the apparatus is increased, and an increase in cost is inevitable.

In the above-described transfer belt in which a paint is included or a paint is applied so that scratches or peeling of the surface layer can be easily found by visual inspection, the physical properties of the transfer belt are changed by the application of the paint. In some cases, however, the transfer belt may not function, and it may take time and effort to apply the paint, and the visual inspection may cause damage or peeling to be missed.

Further, when the life is determined based on the cumulative number of rotations of the transfer belt, the life may be erroneously determined. For example, an image with a high black and white ratio (an image with many black portions)
The electrical stress applied to the transfer belt is different between an image having a low black-and-white ratio (an image having many white portions), and a high voltage must be applied for transfer in an image having a high black-and-white ratio. Join. Further, since an application of a low voltage is sufficient for an image having a low black-and-white ratio, the electric stress is small.

When the electric stress is large, the life is short, and when the electric stress is small, the life is long. Therefore, the life cannot be determined only by the cumulative number of rotations of the transfer belt. It is also necessary to consider the black-and-white ratio.

Further, in a device in which a voltage applying roller and an opposing roller are arranged with the transfer belt interposed therebetween and a pinhole or breakage of the transfer belt is detected based on a current flowing from the voltage applying roller to the opposing roller, a voltage is applied to the transfer belt. The application results in the application of electrical stress, which results in accelerated degradation.

In this method, the current cannot be detected unless the transfer belt is rotating. However, the current value varies with the rotation of the transfer belt. It is difficult to determine whether the noise is caused by the rotation of the transfer belt. For this reason, when the current detection is performed a plurality of times, the cumulative number of rotations of the transfer belt increases, which causes deterioration. Further, since the electrical resistance of the transfer belt changes due to a change in the environment, it is determined whether the detected change in the current value is a change in the current value due to the deterioration of the transfer belt or a change in the current value due to a change in the environment. It will be difficult.

Further, in order to detect a fine defect such as a pinhole in the transfer belt, a voltage applying roller and an opposing roller must be arranged so as to contact at least the entire surface in the direction perpendicular to the moving direction of the transfer belt. Becomes large,
In addition, rising costs are inevitable.

As described above, the conventional detection devices capable of detecting the surface condition of the endless belt-shaped member have respective problems to be solved. In particular, the life of the endless belt-shaped member is not accurately detected and the endurable belt-like member cannot be used. However, there are inconveniences such as erroneously determining that the life has expired, or erroneously determining that it can be used despite the expiration of the life, and continuing to use it, causing image noise or damaging the device. Was. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above various problems and accurately determine the life of an endless belt-shaped member.

[0021]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and the invention of claim 1 comprises an endless belt-like member and a detecting means for detecting an elastic wave generated from the endless belt-like member. An endless belt driving device comprising:

Further, the invention according to claim 2 provides an endless belt-like member, driving means for driving the endless belt-like member, and an elastic wave generated from the endless belt-like member when the endless belt-like member is driven. An endless belt driving device comprising: a detection unit for detecting; and a control unit for controlling the driving unit based on a detection result of the detection unit.

According to a third aspect of the present invention, there is provided an endless belt-like member which is a component of the image forming apparatus, a driving means for driving the endless belt-like member, and an endless belt-like member when the endless belt-like member is driven. An image forming apparatus, comprising: a detection unit that detects an elastic wave generated from the control unit; and a control unit that controls the driving unit based on a detection result of the detection unit.

The endless belt-shaped member is a member involved in image formation in the image forming apparatus. The members involved in image formation include an image carrying belt, a transfer belt, a fixing belt, a cleaning belt, a charging belt, A developing belt is included.

The endless belt-shaped member may be a sheet conveying member in the image forming apparatus, and the sheet includes a document sheet or an image recording sheet.

The control means may control image forming conditions based on the detection result of the detection means.

[0027]

Embodiments of the present invention will be described below.

FIG. 1 is a sectional view schematically illustrating the configuration of an image forming apparatus 100 according to an embodiment of the present invention. Figure 1
In the figure, reference numeral 11 denotes a photosensitive drum as an image carrier, which is configured to be rotationally driven in the direction of arrow a by a drive source (not shown). Around the photoreceptor drum 11, a charging device 12 for applying a charge to the photoreceptor drum 11 along its rotation direction, an exposure device 13 for forming an electrostatic latent image of an image on the photoreceptor drum 11, A developing device 14 for developing the latent image with toner to visualize the toner image; a transfer device 15 for transferring the toner image formed on the photosensitive drum to a recording medium; and cleaning the residual toner that has not been transferred onto the photosensitive drum. A cleaning device 16 and an eraser 17 for removing residual charges on the photosensitive drum are disposed.

A fixing device 20 is disposed downstream of the recording medium conveyed from the transfer device 15 in the direction of conveyance, and although not shown, a recording medium is disposed below the transfer device 15. A paper feeding device for feeding the paper is arranged.
The above configuration is a known electrophotographic image forming apparatus, and thus detailed description is omitted.

Reference numeral 40 denotes a transfer device 15 described later.
1 shows a detection device for detecting a minute elastic wave generated in a transfer belt of FIG.

FIG. 2 is a front view for explaining the details of the configuration of the transfer device 15. In FIG. 2, reference numeral 30 denotes a transfer belt which is stretched between a roller 31a and a roller 31b. The transfer belt 30 is driven in a predetermined direction by driving the roller 31a or the roller 31b by a driving mechanism (not shown). It is configured to move to. In addition, 3
Reference numeral 3 denotes a tension roller that applies a predetermined tension to the transfer belt 30.

A guide member 34 for guiding the recording medium toward the transfer belt 30 is provided near one end of the transfer device 15.
A guide member 35 is disposed, and a contact transfer member 36 for forming a transfer pressure and a transfer electric field is provided inside the transfer belt 30 to re-transfer the toner image transferred on the transfer belt 30 to a recording medium. Are arranged in contact with the transfer belt 30.

A guide member 37 for transporting the recording medium on which the toner image has been retransferred to the fixing device 20 is disposed near the other end of the transfer device 15, and further below the transfer belt. A cleaning device 38 including a rubber blade 38a for removing dirt such as excess toner adhered to the cleaning device 30;
A container 39 for storing the removed waste toner is provided. Note that a detection device 40 for detecting a micro elastic wave is disposed in contact with the lower side of the transfer belt 30.

Next, the behavior of the transfer belt 30 when the transfer belt 30 is damaged by the stress received from the cleaning device 38 during traveling will be described.

The rubber blade 38 of the cleaning device 38 removes stains such as excess toner adhered to the transfer belt 30.
a is in contact with the transfer belt 30. Due to the movement of the transfer belt 30, the rubber blade 38a causes a stick-slip phenomenon (a phenomenon in which sticking stops and slips are repeated) due to its characteristics.
, And a minute reciprocating vibration is repeated on the surface of the transfer belt 30.

Due to the minute reciprocating vibration, the transfer belt 3
The surface of No. 0 is scratched or abraded, and the surface is gradually scraped. The transfer belt 30 is subjected to mechanical stress and is broken at the weakest part.

In general, when an object undergoes minute deformation and destruction regardless of the inside or outside thereof, vibration is generated with the deformation and destruction as an epicenter. Of the vibrations that occur with this minute deformation and destruction, the vibrations that generate particularly minute elastic waves are generally called acoustic emission (AE).

When a mechanical stress is applied to the transfer belt for some reason, an extremely minute internal deformation that cannot be recognized from the outside starts to occur inside the transfer belt, and a minute deformation and destruction occurs. As the microdestruction and destruction progress, eventually, deformation occurs externally, leading to destruction.

In addition, for example, when the internal resistance, volume resistance or surface resistance of the transfer belt changes due to electrical stress even if the outer shape of the transfer belt does not change, the intermolecular bonding of the material constituting the transfer belt is reduced. Since the state changes, an extremely minute internal deformation that cannot be recognized from the outside starts to occur as before, and as the internal deformation progresses, external deformation eventually occurs, leading to destruction.

When microscopic deformation and destruction occur, microelastic wave vibration occurs. The vibration frequency is distributed in the ultrasonic range of about several hundred kHz.

As described above, when stress is applied to the transfer belt for some reason, destruction starts and microelastic wave vibration is generated and propagates inside the material composed of the same molecular bonds. By contacting the detection device 40 with the portion, it is possible to detect the minute elastic wave vibration.

The detecting device 40 may have any configuration as long as it can detect the microelastic wave vibration, and a known detecting device can be used.

FIG. 3 is a diagram for explaining frequency ranges of various vibrations generated in the image forming apparatus and their vibration intensities. The frequency of mechanical vibration generated from a motor or other driving mechanism as a driving source, or the frequency of vibration generated when the rubber blade 38a of the cleaning device 38 comes into contact with the transfer belt 30 is mainly several Hz to several tens kHz or less. Since the frequency is concentrated and the frequency of the above-described microelastic wave vibration is distributed in the ultrasonic region of about several hundred kHz, it is easy to identify the microelastic wave from the frequency.

FIG. 4 is a flow chart for explaining a process of identifying a minute elastic wave vibration when the transfer belt is driven.
First, it is confirmed that the transfer belt has started to be driven (step P
1) The detection device 40 is turned on to start vibration detection (step P2), and further, it is determined whether or not the detected vibration frequency f exceeds several hundred kHz (f> several hundred kHz) (step P3). If the detected vibration frequency f is several hundreds kHz or more, it is determined whether or not the condition is a plurality of times (N times) (step P4). Count the number of times N (step P
5) When the predetermined number N has been reached, the drive of the transfer belt is stopped (step P6), a warning signal for warning that the life has been reached is output (step P7), and the process is terminated.

If the determination in step P4 does not require a plurality of (N) detections, the drive of the transfer belt is stopped by one detection (step P8), and a warning signal for warning that the life has been reached is given. Is output (step P9), and the process ends.

If it is determined in step P3 that the detected vibration frequency f is not more than several hundred kHz, no micro elastic wave vibration is generated, that is, no minute deformation and destruction is generated, and the transfer belt is usable. Since it means that there is, a command to execute the printing process is issued (step P10), and the process ends.

In the process of step P5, whether a plurality of (N) times of detection or a number of times of detection may be appropriately determined by design.

In the above-described detection of the minute elastic wave vibration at the time of driving the transfer belt, the detection is performed by bringing the detection device 40 into contact with a part of the transfer belt, but other members that are in contact with the transfer belt, for example, The detection can also be performed by bringing the detection device 40 into contact with the roller 31a or the roller 31b.
Further, even when the transfer belt is stopped, tension is applied to the transfer belt, so that even when the transfer belt is stopped, a small deformation and destruction may occur and a minute elastic wave vibration may occur. It can be detected by the device 40.

Further, the above-described detection of the minute elastic wave vibration due to the minute deformation and destruction of the transfer belt can be performed by detecting the detection device in contact with the transfer belt or the detection device in contact with another member in contact with the transfer belt. Is detected by
Micro elastic waves can be captured as ultrasonic waves and detected without contact. In this case, the detection may be performed when the transfer belt is stopped because there is a possibility of being disturbed by environmental noise.

The detection of deformation and destruction when the transfer belt is damaged by the stress from the cleaning device during running has been described. However, it is needless to say that the detection means for detecting minute deformation and destruction of the belt according to the present invention is not limited to the transfer belt, but can be applied to a charging belt, a cleaning belt, a belt-shaped photoconductor, a fixing belt, and other belts. Hereinafter, this will be described.

FIG. 5 is a diagram showing a configuration of an image forming apparatus in which a detecting device 40 for detecting minute deformation and destruction is arranged on the charging belt 51. The detecting device 40 is configured such that the charging belt 51 contacts the photosensitive drum 11 It detects small deformation and destruction caused by stress caused by rubbing and stress caused by electric charge. The same members as those in the configuration shown in FIG. 1 are denoted by the same reference numerals, and detailed description will be omitted.

FIG. 6 is a view showing the configuration of an image forming apparatus in which a detecting device 40 for detecting minute deformation and destruction is arranged on the developing belt 52. The detecting device 40 is configured such that the developing belt 52 contacts the photosensitive drum 11 It detects small deformation and destruction caused by stress caused by rubbing and stress caused by electric charge. The same members as those in the configuration shown in FIG. 1 are denoted by the same reference numerals, and detailed description will be omitted.

FIG. 7 is a diagram showing the configuration of an image forming apparatus in which a detecting device 40 for detecting minute deformation and destruction is disposed on the cleaning belt 53. The detecting device 40 is configured such that the cleaning belt 53 contacts the photosensitive drum 11 It detects small deformation and destruction caused by stress caused by rubbing and stress caused by electric charge. The same members as those in the configuration shown in FIG. 1 are denoted by the same reference numerals, and detailed description will be omitted.

FIG. 8 is a view showing a configuration of an image forming apparatus in which a detecting device 40 for detecting minute deformation and destruction is arranged on the belt-shaped photosensitive member 54. It detects small deformation and destruction caused by stress caused by rubbing in contact with the roller and stress caused by electric charge. The same members as those in the configuration shown in FIG. 1 are denoted by the same reference numerals, and detailed description will be omitted.

FIG. 9 is a view showing a configuration of an image forming apparatus in which a detecting device 40 for detecting minute deformation and destruction is arranged on the fixing belt 55. The detecting device 40 rubs when the fixing belt 55 contacts the recording medium. It detects small deformation and destruction caused by the stress caused by the stress and the stress caused by the charge. The same members as those in the configuration shown in FIG. 1 are denoted by the same reference numerals, and detailed description will be omitted.

As described above, in the embodiment of the present invention, the configuration in which the life of the endless belt-shaped member is determined is applied to the transfer belt of the image forming apparatus and other endless belt-shaped members constituting the image forming apparatus. However, it goes without saying that the configuration for determining the life of the endless belt-shaped member according to the present invention can be applied to various apparatuses using the endless belt-shaped member other than the image forming apparatus.

Further, in the above-described embodiment, an example is described in which the configuration for determining the life of the endless belt-shaped member according to the present invention is applied to the electrophotographic image forming apparatus. The configuration for determining the life of the member is not limited to the application to an electrophotographic image forming apparatus, but may be an electrostatic recording type image forming apparatus that records an electrostatic latent image with a multi-stylus, or a direct image formation method using a toner jet. Needless to say, the present invention can be applied to a recording type image forming apparatus.

[0058]

As described above in detail, according to the present invention, the microscopic wave generated inside the endless belt-like member based on the elastic wave vibration generated from the minute deformation and destruction based on the stress applied to the endless belt-like member. Detects various deformation failures,
Since the life is determined, it is possible to take measures such as replacing the endless belt-shaped member before it breaks down and breaks down.

Since the life determination is based on elastic wave vibration indicating the occurrence of minute deformation and destruction occurring inside the endless belt-shaped member, the life can be accurately determined. Unlike this type of detection means, there is no erroneous determination that the service life has expired while the device is in a state where it can be used, or erroneous determination that the device can be used even though the service life has expired.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically illustrating the configuration of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a front view illustrating the configuration of a transfer device of the image forming apparatus shown in FIG.

FIG. 3 is a diagram illustrating frequency ranges and vibration intensities of various vibrations generated in the image forming apparatus.

FIG. 4 is a flowchart illustrating a process of identifying a minute elastic wave when the transfer belt is driven.

FIG. 5 is a diagram illustrating a configuration of an image forming apparatus in which a detection device that detects minute deformation and destruction is arranged on a charging belt.

FIG. 6 is a diagram illustrating a configuration of an image forming apparatus in which a detection device that detects minute deformation and destruction is arranged on a developing belt.

FIG. 7 is a diagram illustrating a configuration of an image forming apparatus in which a detection device that detects minute deformation and destruction is disposed on a cleaning belt.

FIG. 8 is a diagram illustrating a configuration of an image forming apparatus in which a detection device that detects minute deformation and destruction is arranged on a belt-shaped photoconductor.

FIG. 9 is a diagram illustrating a configuration of an image forming apparatus in which a detection device that detects minute deformation and destruction is disposed on a fixing belt.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 image forming apparatus 11 photoreceptor drum (image carrier) 12 charging device 13 exposing device 14 developing device 15 transfer device 16 cleaning device 17 eraser 20 fixing device 30 transfer belt 31a, 31b roller 33 tension roller 34, 37 guide member 36 contact Transfer member 38 Cleaning device 38a Rubber blade 40 Detecting device 51 Charging belt 52 Developing belt 53 Cleaning belt 54 Belt-shaped photoreceptor 55 Fixing belt

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/02 102 G03G 15/02 102 2H034 15/08 501 15/08 501F 2H035 15/16 15/16 2H077 15/20 101 15/20 101 3F048 21/00 21/00 3F049 21/10 352 3J049 21/00 352 312 (72) Inventor Kenzo Toya Osaka International Building 2-3-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka Minolta Co., Ltd. (72) Inventor Haruhiko Hori 2-3-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka Osaka International Building Minolta Co., Ltd. F-term (reference) 2G024 AB08 BA12 CA13 FA14 2G064 AA12 BA02 CC41 CC62 DD15 2H003 AA11 BB11 CC04 2H032 BA09 BA18 BA23 2H033 AA36 BA12 BE03 CA34 CA57 2H034 AA06 BA00 FA06 FA07 2H035 CB06 CE08 C G01 2H077 AD07 DA24 DB10 GA04 3F048 AA01 AB01 BA08 BA26 BB05 BC03 DA06 EA01 EB24 3F049 AA10 BA00 EA00 LA01 LB03 3J049 AA01 BB05 BB22 BG10 CA10

Claims (8)

[Claims] 1. An endless belt driving device, comprising: an endless belt-shaped member; and a detecting means for detecting an elastic wave generated from the endless belt-shaped member. 2. An endless belt-shaped member; a driving unit for driving the endless belt-shaped member; a detection unit for detecting an elastic wave generated from the endless belt-shaped member when the endless belt-shaped member is driven; An endless belt driving device, comprising: control means for controlling the driving means based on a detection result of the detection means. 3. An endless belt-shaped member which is a constituent member of the image forming apparatus; a driving means for driving the endless belt-shaped member; and an elastic wave generated from the endless belt-shaped member when the endless belt-shaped member is driven. An image forming apparatus comprising: a detection unit configured to detect a state of the image data; and a control unit configured to control the driving unit based on a detection result of the detection unit. 4. The image forming apparatus according to claim 3, wherein the endless belt-shaped member is a member involved in image formation in the image forming apparatus. 5. The image forming apparatus according to claim 4, wherein the members involved in image formation include an image carrying belt, a transfer belt, a fixing belt, a cleaning belt, a charging belt, and a developing belt. 6. The image forming apparatus according to claim 3, wherein the endless belt-shaped member is a sheet conveying member in the image forming apparatus. 7. The image forming apparatus according to claim 6, wherein the paper sheet is a document sheet or an image recording sheet. 8. The image forming apparatus according to claim 3, wherein the control unit controls an image forming condition based on a detection result of the detection unit.