JP3354366B2 - Electrophotographic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus for forming an image on printing paper by an electrophotographic method.

[0002]

2. Description of the Related Art Currently, electrophotographic apparatuses are used in laser printers, copiers, facsimile machines, and the like. An electrophotographic apparatus forms an image on printing paper by an electrophotographic method.

That is, the surface of the photoreceptor is uniformly charged by discharging of a charger, and the charged surface of the photoreceptor is selectively neutralized by exposure of an exposing device to form an electrostatic latent image. The electrostatic latent image is developed with toner supplied from a developing device, and the toner is transferred to printing paper conveyed by a paper conveying mechanism by the potential of the transfer device. By fixing the toner transferred to the printing paper by heating and pressurizing a fixing device, an image is formed on the printing paper by the fixed toner.

[0004] There is a type of such an electrophotographic apparatus in which a transfer belt or a transfer roller is disposed as an intermediate transfer member between a photosensitive member and printing paper. In this case, the toner obtained by developing the electrostatic latent image on the photoconductor is transferred to an endless intermediate transfer body that is stretched freely by a plurality of support rollers,
The toner attached to the intermediate transfer member is transferred to a printing paper. There is also a model in which a paper transport mechanism transports printing paper by a transport belt. In this case, the endless transport belt is stretched by a plurality of support rollers so as to be freely circulated, and the printing paper is sequentially transported by the circulated transport belt.

In the above-described electrophotographic apparatus, in order to maintain good quality of an image formed on printing paper, the density of toner is detected on the surface of a photoreceptor by a density sensor, and the detected value is detected by a developing unit or the like. There are also models that reflect this in the control of exposure units and transfer units.

[0006]

In the above-described electrophotographic apparatus, the toner density is detected on the surface of the photoconductor in order to improve the image quality.

As a density sensor for detecting the toner density, an optical sensor such as a photodiode is generally used, but such an optical sensor does not have good linearity in detection characteristics. For this reason, it is difficult to accurately detect the toner density from a low density to a high density, and particularly when the toner has a high density, the detection accuracy is reduced. Proposals aimed at solving such problems are disclosed in Japanese Patent Application Laid-Open Nos. H6-186816 and 6-109643.

For example, in an electrophotographic apparatus disclosed in Japanese Patent Application Laid-Open No. H6-186816, the surface potential of an electrostatic latent image of a gradation density pattern formed on a photoreceptor is detected by a potential sensor, and the developed gradation density is detected. Read the pattern with an optical sensor,
A relational expression between the surface potential of the photoreceptor and the amount of adhered toner is obtained. When the toner density is low, the toner density is detected by an optical sensor. When the toner density is high, the toner density is calculated from the surface potential and a relational expression.

In the electrophotographic apparatus disclosed in Japanese Patent Application Laid-Open No. 6-109643, the surface of the photoconductor at the time of toner adhering and at the time of no toner adhering are read by an optical sensor, and the read results are logarithmically compressed. The toner density is calculated from the difference between when the toner is attached and when it is not attached.

Although the accuracy of detecting the toner density can be improved by the above-described processing, it is difficult to accurately detect the toner density because the toner density is read by an optical sensor in each case.

[0011]

According to the first aspect of the present invention,
The surface of the photoreceptor is uniformly charged by discharging of the charger, and the surface of the charged photoreceptor is selectively neutralized by exposure of the exposing device to form an electrostatic latent image, and the electrostatic latent image is developed. Developing with toner supplied from an image transfer device, transferring the toner to printing paper by an intermediate transfer member, and fixing the toner transferred to the printing paper by a fixing device. Red in the opposite position
A laser light source that emits external laser light is disposed, and a position detection element that detects the position of the laser light emitted from the laser light source and reflected by the intermediate transfer body at two positions is provided.
An adhesion amount detecting means for detecting an adhesion amount of the toner transferred to the intermediate transfer body from an interval between two detection positions by the position detection element is provided. Therefore, since the laser light emitted from the laser light source is infrared light , it is
When the toner is applied to the transfer position, the toner
It is reflected on both surfaces such as the intermediary transfer member. in this way
The position of the two reflected laser beams is determined by the position detector.
Since the toner is detected, the adhesion amount detecting means detects the adhesion amount of the toner from the interval between the two detection positions .

According to a second aspect of the present invention, an electrostatic latent image is formed by uniformly charging the surface of a photoreceptor by discharging of a charger, and selectively removing the charged surface of the photoreceptor by exposure of an exposing device. Is formed by developing the electrostatic latent image with toner supplied from a developing device, and the toner is transferred to a printing paper, and then fixed by a fixing device. A laser light source that emits infrared laser light is disposed at a position facing the surface obliquely, and a position detection element that detects the position of the laser light emitted from this laser light source and reflected by the printing paper at two places. And an adhesion amount detecting means for detecting an adhesion amount of the toner transferred to the printing paper from an interval between two detection positions by the position detection element. Therefore, the laser light source to emit
Since the laser light is infrared,
When the toner is applied to the transfer position, the toner surface
The light is reflected on both surfaces such as the intermediate transfer member. like this
The position of the two laser beams reflected by the
Therefore, the adhesion amount detecting means detects the adhesion amount of the toner from the interval between the two detection positions .

According to a third aspect of the present invention, an electrostatic latent image is formed by uniformly charging the surface of a photoreceptor by discharging of a charger, and selectively removing the charged surface of the photoreceptor by exposure of an exposing device. Is formed by developing the electrostatic latent image with toner supplied from a developing device, and the toner is transferred to printing paper and then fixed by a fixing device. At a position facing and inclined to the surface
A laser light source for emitting infrared laser light is arranged, the position of the laser beam reflected by the photosensitive member is emitted from the laser light source is provided the position detection elements for detecting at two locations, two locations by the position detecting device And an adhesion amount detecting means for detecting the adhesion amount of the toner transferred to the photosensitive member from the interval between the detection positions . Therefore, since the laser light emitted from the laser light source is infrared, the toner is transferred to an intermediate transfer member or the like.
When irradiated at the imaged position, the toner surface and intermediate transfer
It is reflected on both surfaces, such as the body. Reflected in this way
The position of the two laser beams is detected by the position detector.
Therefore, the adhesion amount detecting means detects the adhesion amount of the toner from the interval between the two detection positions .

[0014]

[0015]

[0016]

[0017]

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. First, a digital copying machine 1 exemplified as an electrophotographic apparatus has an image reading unit 2 and an image forming unit 3 as shown in FIG.
The image reading section 2 is obtained by connecting an image processing circuit 5 to an image scanner 4, and the image processing circuit 5 is connected to a laser scanner 6 which is an exposure device of the image forming section 3.

The image forming section 3 has a rotatable photosensitive drum 7 as a photosensitive member. On the outer peripheral surface of the photosensitive drum 7, a drum cleaner 8, a discharging lamp 9, a charger 10, the laser scanner 6, a potential sensor 11, a developing unit 12, an optical sensor 13, and a transfer belt 1 as an intermediate transfer body
4 are arranged oppositely in order. This transfer belt 14
Is endlessly formed and is circulated by a plurality of support rollers 15 so as to be freely circulated, and a belt cleaner 16 and a transfer unit 17 are arranged on the outer surface thereof so as to face each other.

A paper transport path 18 communicates with the gap between the transfer unit 17 and the transfer belt 14, and the paper transport path 18 communicates from a paper feed cassette 19 to a paper output tray 20. At a position facing the paper feed cassette 19,
A paper feed mechanism 22 is provided as a part of the paper transport mechanism 21, and a part of the paper transport mechanism 21 is provided at a position communicating with the paper discharge tray 20 from the gap between the transfer device 17 and the transfer belt 14. Belt transport mechanism 23 and fixing device 2
4 are sequentially arranged. The belt transport mechanism 23
Has an endless transport belt 25, which is stretched by a plurality of support rollers 26 so as to be able to circulate freely.

The digital copying machine 1 exemplified here
In this case, an adhesion amount measuring unit 27 is disposed opposite to a portion where the transfer belt 14 circulates from the position of the photosensitive drum 7 to the position of the paper transport path 18. This adhesion amount measuring unit 2
7, a visible light laser 28 as a laser light source and a PSD (Position Sensit) as a position detecting element, as shown in FIG.
ive Device) 29. The visible light laser 2
Numeral 8 is disposed at a position facing the surface of the transfer belt 14 at an angle with a condensing lens 30 interposed therebetween.
D <b> 29 is disposed via a condenser lens 30 at a position where laser light emitted from the visible light laser 28 and reflected by the transfer belt 14 is detected. One of the support rollers 15 is disposed on the back side of the transfer belt 14 at a position where the visible light laser 28 and the PSD 29 face each other.

A rotary encoder (not shown) is connected to one of the support rollers 15 on which the transfer belt 14 is stretched, and a rotation detector 31 is connected to the rotary encoder. . Further, FIG.
As shown in the figure, the potential sensor 11 and the optical sensor 1
3, the adhesion amount measurement unit 27, the rotation amount detection unit 31, the drive unit 32 of the photosensitive drum 7, the drive unit 33 of the transfer belt 14, the drive unit 34 of the transport belt 25, and the drive of the paper feed mechanism 22 Unit 35, driving unit 36 of the transfer device 17
Are connected to an I / O (Input / Output) control unit 37, and an information processing unit 38 is connected to the I / O control unit 37. In addition, since the control circuit 39 is connected to the visible light laser 28 and the data processing circuit 40 is connected to the PSD 29, the adhesion amount measuring section 27 uses the I / O circuit 39, 40 It is connected to the control unit 37.

The information processing section 38 comprises a microcomputer, and includes a CPU (Central Processing Unit) and an RO.
M (Read Only Memory) and RAM (Random Access Memory)
Having. By performing various data processing based on various data input from the potential sensor 11, the optical sensor 13, the adhesion amount measuring unit 27, and the rotation amount detecting unit 31, and performing various data processing, The operation of the driving units 32 to 36 and the like is controlled.

The digital copying machine 1 of the present embodiment has a pattern forming unit, a circulation detecting unit, a first position detecting unit, a second position detecting unit, a first storing unit, a second storing unit, an attached amount detecting unit, an operation. Control means. The pattern forming unit drives the image forming unit 3 in accordance with a preset test pattern, and transfers the electrostatic latent image of the test pattern formed on the photosensitive drum 7 by the laser scanner 6 from the developing unit 12. After being developed by the supplied toner 41, it is transferred to the transfer belt 14. The circulation detecting unit detects the transfer belt 1 by the rotation amount detecting unit 31.
4 is recognized, and the position of the toner 41 of the test pattern transferred to the surface thereof is detected.

The first position detecting means emits the laser beam of the visible light laser 28 to a position on the surface of the transfer belt 14 where the toner 41 is not transferred, as shown in FIG. The position of the laser beam reflected on the surface of the transfer belt 14 is detected by the PSD 29 and is output to the information processing section 38 as first position data. As shown in FIG. 2B, the second position detecting means emits the laser light of the visible light laser 28 to a position on the surface of the transfer belt 14 where the toner 41 has been transferred, and The position of the laser beam reflected by the PSD
29, and outputs this to the information processing section 38 as second position data.

The first storage means stores the first position data by the information processing section 38, and the second storage means stores
The second position data is stored by the information processing unit 38.
The adhesion amount detecting means subtracts the first position data from the second position data by the information processing section 38 and multiplies the calculation result by a predetermined constant, thereby obtaining the transfer belt 1.
Then, the amount of the toner 41 transferred to the image No. 4 is detected.

The operation control means suspends the operation of the movable part which affects the position detection of the PSD 29 in synchronization with the detection timing of the PSD 29. More specifically, since the adhesion amount measuring unit 27 detects the adhesion amount of the toner 41 on the surface of the transfer belt 14, if the transfer belt 14 is circulating at this point, the detection result is affected. Since the transfer belt 14 is provided so as to be circulated integrally with the photosensitive drum 7 by being pressed against the photosensitive drum 7, the operation control means synchronizes the detection timing of the PSD 29 with the information processing section 38 to control the photosensitive drum 7. The driving unit 32 and the driving unit 33 of the transfer belt 14 are temporarily stopped.

In such a configuration, the digital copying machine 1 of the present embodiment reads the image of the document 42 by the image reading unit 2 and copies the image to the printing paper 43 by the image forming unit 3.

More specifically, in the image reading section 2, the original 4
The image 2 is optically scanned by the image scanner 4 and converted into image data. This image data is transmitted from the image processing circuit 5 to the laser scanner 6 of the image forming unit 3. At this time, the rotating photosensitive drum 7 is
Is uniformly charged by the discharge of the charger 10, and the surface of the photosensitive drum 7 that rotates while being charged is exposed by the laser scanner 6 that operates according to image data. Since the charged surface of the photosensitive drum 7 is selectively neutralized by this exposure to form an electrostatic latent image, the electrostatic latent image is developed by the toner 41 supplied from the developing device 12 and the measured value is measured. The toner 41 is transferred to the transfer belt 14.

At this time, the printing paper 43 is fed from the paper feeding cassette 19 to the paper transport path 18 by the paper feeding mechanism 22, so that the toner 41 transferred to the transfer belt 14 is
The image is transferred to the printing paper 43 by the potential 7. The printing paper 43 to which the toner 41 has been transferred is conveyed to the fixing device 24 by the conveyance belt 25, so that the toner 41 is pressed and heated by the fixing device 24, and
Fix to 3. Printing paper 43 to which this toner 41 has been fixed
Is discharged onto the paper discharge tray 20, whereby the copying operation of the digital copying machine 1 is completed. The toner 41 remaining on the surface of the rotating photosensitive drum 7 is removed from the drum cleaner 8.
, And the toner 41 remaining on the surface of the circulating transfer belt 14 is removed by the belt cleaner 16.

As described above, an image is formed on the printing paper 43 with the toner 41 by the electrophotographic method.
The print density 1 changes due to a change over time of the electrostatic characteristics of the photosensitive drum 7 and an environmental change. However, the digital copying machine 1 exemplified here has the toner 4
The print density of the toner 41 is constantly corrected by detecting the print density of No. 1 and controlling the drive voltages of the charger 10, the developing device 12, and the transfer device 17 in accordance with the detected print density.

Therefore, the processing operation for detecting the print density of the toner 41 in order to execute such a correction operation will be sequentially described. First, in a state where all the movable parts such as the photosensitive drum 7 and the transfer belt 14 are stopped, as shown in FIG. 2A, a visible light laser is first applied to the surface of the transfer belt 14 where the toner 41 is not transferred. The laser light of 28 is emitted, and the position of the laser light reflected on the surface of the transfer belt 14 is detected by the PSD 29.

Next, as described above, the image forming section 3 is driven to transfer the toner 41 to the surface of the transfer belt 14 in a test pattern shape, and the toner 41 adheres as shown in FIG. When moving to a position facing the amount measuring unit 27, all the movable parts such as the photosensitive drum 7 and the transfer belt 14 are temporarily stopped. In this state, the laser light of the visible light laser 28 is emitted to the toner 41 of the test pattern transferred to the surface of the transfer belt 14, and the position of the laser light reflected on the surface of the toner 41 is detected by the PSD 29.

Thus, the displacement of the position of the laser beam reflected on the surface of the transfer belt 14 is detected based on the presence or absence of the toner 41, and the amount of toner 41 attached is detected by multiplying the displacement by a predetermined constant. . The amount of toner 41 thus detected corresponds to the print density of the toner 41, and accordingly, the charging device 10, the developing device 12, the transfer device 1
7, the print density of the toner 41 is constantly corrected to be constant.

Since the digital copying machine 1 of the present embodiment measures the print density of the toner 41 based on the transfer thickness as described above, the detection accuracy is higher than when the print density of the toner 41 is read optically. Is good, and the print density of the toner 41 can be measured with good characteristics from low density to high density. In addition, since all the movable parts are stopped in synchronization with the detection timing of the PSD 29 as described above, the print density of the toner 41 can be accurately detected on the surface of the transfer belt 14 where vibration is likely to occur.

Since the transfer belt 14 is supported by the support roller 15 at the detection position, the detection accuracy is further improved. When the test pattern of the toner 41 is transferred to the transfer belt 14 to detect the amount of adhesion as described above, the image forming unit 3 needs to be driven, but the image scanner 4 and the paper transport mechanism 21 need to be driven. There is no. Therefore, in the operation for detecting the print density of the toner 41 as described above, the image scanner 4 and the paper transport mechanism 21 are used.
Only the movable part of the image forming unit 3 may be temporarily stopped at the detection timing without being driven from the beginning.

In the above-described digital copying machine 1, the test pattern transferred to the transfer belt 14 in order to detect the amount of toner 41 attached is assumed to be a rectangular pattern having the highest density. The present invention is not limited to the method, and it is also possible to form such a test pattern in stepwise multiple gradations. Here, the position detecting element for detecting the reflection position of the laser beam is one PSD2.
9, the structure is simplified and the productivity is improved. However, the structure is changed to a CCD (Charge Coupled Device).
ce) It is also possible to form an array.

In the digital copying machine 1 described above, the surface position of the transfer belt 14 is measured by the adhesion amount measuring unit 27, and then the transfer belt 14 is cycled to transfer the toner 41 to the same position. The position is determined by the adhesion amount measuring unit 27.
It was assumed that measurement was performed by In this case, there is no need to worry about uneven thickness of the transfer belt 14 and the toner 41
Can be accurately detected, but it is necessary to make the transfer belt 14 go around once after measuring the surface of the transfer belt 14 and before measuring the surface of the toner 41. That is, if the thickness of the transfer belt 14 is sufficiently uniform, it is not necessary to measure the amount of the toner 41 attached at the same position, and the surface measurement between the transfer belt 14 and the toner 41 is continuously performed to increase the operation speed. Can be completed.

Further, in the above-described digital copying machine 1,
Although the adhesion amount measuring unit 27 is arranged to face the transfer belt 14 as an intermediate transfer body and detects the adhesion amount of the toner 41 transferred to the surface of the transfer belt 14, the present invention is limited to the above method. It is not something to be done. For example, as shown in FIG. 4 and FIG.
The toner 41 transferred to the printing paper 43 is disposed opposite to the upper surface for transporting the printing paper 43 onto which the toner 41 is transferred.
Can be detected. As shown in FIGS. 6 and 7, the adhesion amount measuring unit 27 is disposed opposite to a position where the transferred toner 41 of the photosensitive drum 7 as the photosensitive member is conveyed, and the toner applied to the surface of the photosensitive member 7 is It is also possible to detect the amount of 41 attached.

Each of the above three methods has advantages and disadvantages, and therefore, it is preferable to select them according to various conditions such as the specifications of the apparatus. For example, in the method in which the adhesion amount measuring unit 27 is arranged to face the conveyor belt 25, the adhesion amount of the toner 41 finally transferred to the printing paper 43 is detected, so that this is closest to the actual print density. On the other hand, the printing paper 43 is consumed for detecting the density of the toner 41. Transfer amount measuring unit 27 is transferred to transfer belt 1
4 or the photosensitive drum 7, the printing paper 4
Although it is not necessary to consume 3, the amount of toner 41 attached at such a position may have a large error from the actual print density.

In the digital copying machine 1 described above, the toner 41 applied to the surface of the photosensitive drum 7 is
However, there is also an electrophotographic apparatus (not shown) that directly transfers the toner 41 from the photosensitive drum 7 to the printing paper 43 without having such a transfer belt 14. In this case, the adhesion amount measuring unit 27 detects the adhesion amount of the toner 41 on the surface of the photosensitive drum 7 or the printing paper 43. In other words, the method in which the adhesion amount measuring unit 27 is disposed to face the photosensitive drum 7 and the transport belt 25 as described above can be applied to an electrophotographic apparatus having no transfer belt 14.

An electrophotographic apparatus (not shown) in which the photosensitive member is not the photosensitive drum 7 but a photosensitive belt, or an electrophotographic apparatus in which the printing paper 43 is transported by a feed roller or a guide plate without having the transport belt 25 (see FIG. Although not shown), the adhesion amount measuring unit 27 may be disposed at a corresponding position in such a case.

Further, the adhesion amount measuring unit 27 is connected to the photosensitive drum 7
Since there is a concern that the laser beam emitted from the adhesion amount measuring unit 27 exposes the photosensitive drum 7 and the toner 41 is scattered, if this is a problem, another method may be selected. preferable.

In the above-described digital copying machine 1, since the image is expressed in black and white, the toner 41 is one type of black. For example, in a full-color electrophotographic apparatus,
Four developing devices 12 are arranged to face the photosensitive drum 7 and YM
A color image is formed with CK (Yellow, Magenta, Cyanide, Black) toner. In the case where a plurality of color toners are used, there is a concern that the surface cannot be properly detected by one type of laser light because the spectral reflectances are largely different depending on the colors. If this poses a problem, it is preferable to provide a plurality of laser light sources and position detecting elements in accordance with the type of toner, and to detect toners of all colors satisfactorily.

More specifically, when the toner is of four types of YMCK, it is supposed that four laser light sources and four position detecting elements are provided so as to individually detect the YMCK. As shown in FIG. 9, actually, two visible light lasers 28 and two PSDs 29 are provided, and it is also possible to detect YM toner satisfactorily on the one hand and CK toner satisfactorily on the other hand.

Further, the wavelength of the laser light of the laser light source is
If the color can be changed to a wavelength that is reflected by each of the different toners, a single laser light source and a single position detection element can detect a plurality of color toners such as YMCK satisfactorily.

In the digital copying machine 1 described above, the transfer belt 14 is cycled and the measurement is performed twice in order to detect the surface of the transfer belt 14 and the surface of the toner 41 at the same position. The present invention is not limited to the above method. For example, as shown in FIG. 10, an infrared laser 51 is provided as a laser light source, a CCD array 52 is provided as a position detecting element, and a transfer belt 14 and a toner 41 are provided.
Can be detected simultaneously.

More specifically, when the infrared laser 51 irradiates the transfer belt 14 onto which the toner 41 has been transferred with infrared laser light, this laser light is reflected by the surface of the toner 41 and transmitted through the toner 41. The light is also reflected on the surface of the transfer belt 14. Since the two laser beams reflected at the two places are incident on the two places of the CCD array 52, peaks are generated at two places in the parallel output of the CCD array 52 as shown in FIG. Since the interval between the peaks is proportional to the amount of toner 41 attached, the amount of toner 41 attached can be detected by multiplying the peak interval by a predetermined constant.

In this case, the surface of the transfer belt 14 and the surface of the toner 41 can be detected at the same time, and the amount of the toner 41 attached can be measured at one time, so that the operation can be completed at high speed. Further, the degree of exposure of the infrared laser beam to the photosensitive drum 7 is extremely low, and therefore, the above-described adhesion amount measuring unit 53 is most suitable for a method of disposing the photosensitive drum 7 so as to face the photosensitive drum 7.

The above-mentioned various modifications can be combined with each other as long as the contents do not conflict with each other.

[0051]

According to the first aspect of the present invention, an infrared laser beam is emitted to a position obliquely facing the surface of the intermediate transfer member.
That the laser light source is provided, the position of the laser beam reflected by and emitted intermediate transfer member from the laser light source is provided the position detection elements for detecting at two places, Nica by the position detecting device
The laser light emitted from the laser light source is infrared because the adhesion amount detecting means for detecting the adhesion amount of the toner transferred to the intermediate transfer member from the distance between the detection positions is provided.
Is applied to the position where the toner is transferred to the intermediate transfer member.
The surface of the toner and the surface of the intermediate transfer member
And two lasers reflected in this way
Since the position of the light is detected by the position detecting element,
Attachment amount detection means detects the amount of toner
The amount of landing can be detected .

According to a second aspect of the present invention, an infrared ray recording device is provided at a position inclined and opposed to the surface of the printing paper on which the toner is transferred.
A laser light source that emits laser light is arranged, and the position of the laser light emitted from the laser light source and reflected by the printing paper is determined.
A laser light source is provided by providing a position detection element for detecting at two locations and providing an adhesion amount detection means for detecting an adhesion amount of the toner transferred to the printing paper from an interval between the two detection positions by the position detection element. The emitted laser light is infrared
Therefore, this is the position where the toner is transferred to the intermediate transfer body etc.
The surface of the toner and the surface of the intermediate transfer member
And reflected both, and also reflected in this way
The position of the laser beam is detected by the position detection element.
Then, from the interval between these two detection positions, the adhesion amount detection means
The amount of toner adhesion can be detected .

According to a third aspect of the present invention, there is provided an infrared ray laser at a position obliquely opposed to the surface of the photosensitive member onto which the toner has been transferred.
A laser light source that emits laser light is arranged, and two positions of the laser light emitted from this laser light source and reflected by the photoconductor are located.
The position detecting device for detecting at providing, in the position detecting device
By providing the adhesion amount detecting means for detecting the adhesion amount of the toner transferred to the photoreceptor from the interval between the two detection positions , the laser light emitted from the laser light source is infrared,
This irradiates the position where the toner is transferred to the intermediate transfer body etc.
The toner surface and the surface of the intermediate transfer member, etc.
And the two rays reflected in this way
Since the position of the light is detected by the position detecting element,
The adhesion amount detecting means detects the toner
The amount of adhesion can be detected .

[0054]

[0055]

[0056]

[0057]

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the entire structure of a digital copying machine which is a first embodiment of the electrophotographic apparatus of the present invention.

FIG. 2 shows a positional relationship between a transfer belt, a visible light laser as a laser light source, and a PSD as a position detecting element, and FIG.
FIG. 4 is a side view illustrating a state where the toner is not transferred to the transfer belt, and FIG. 7B is a schematic view illustrating a state where the toner is transferred to the transfer belt.

FIG. 3 is a block diagram showing a circuit structure of a main part of the digital copying machine.

FIG. 4 is a schematic diagram showing the entire structure of a digital copying machine in which an adhesion amount measuring unit is arranged to face a conveyor belt as a first modification.

5A and 5B are diagrams showing a positional relationship between a transport belt, a visible light laser, and a PSD, wherein FIG. 5A is a schematic diagram showing a state in which the transport belt is not transporting print paper, and FIG. 5B is a print paper on which toner is transferred; FIG. 3 is a schematic diagram showing a state in which the sheet is being conveyed.

FIG. 6 is a schematic diagram showing the entire structure of a digital copying machine in which an adhesion amount measuring unit is arranged to face a photosensitive drum as a photosensitive member as a second modified example.

FIG. 7 is a schematic diagram illustrating a positional relationship among a photosensitive drum, a visible light laser, and a PSD.

FIG. 8 is a schematic diagram showing a structure in which two visible light lasers and two PSDs are arranged to face a transfer belt as a third modified example.

FIG. 9 is a schematic diagram showing, as a fourth modification, a structure in which two visible light lasers and two PSDs are opposed to each other on a conveyor belt.

FIG. 10 is a schematic diagram showing a structure in which an infrared laser as a laser light source and a CCD array as a position detecting element are arranged opposite to a transfer belt as a fifth modified example.

FIG. 11 is a characteristic diagram showing detection results of a CCD array.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrophotographic apparatus 6 Exposure device 7 Photoreceptor 10 Charger 12 Developing device 14 Intermediate transfer body 21 Paper transport mechanism 24 Fixing device 28,51 Laser light source 29,52 Position detecting element 41 Toner 43 Printing paper

Continuation of front page (56) References JP-A-2-124406 (JP, A) JP-A-59-120909 (JP, A) JP-A-57-207264 (JP, A) JP-A-61-14652 (JP) JP-A-7-271265 (JP, A) JP-A-4-274734 (JP, A) JP-A-61-124973 (JP, A) JP-A-2-176767 (JP, A) 2-95046 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/00 G03G 15/08 G03G 21/00 G01B 11/00-11/30

Claims (3)

(57) [Claims] 1. The surface of a photoreceptor is uniformly charged by discharging of a charger, and the charged surface of the photoreceptor is selectively neutralized by exposure of an exposing device to form an electrostatic latent image. An electrophotographic apparatus that develops an electro-latent image with toner supplied from a developing device, transfers the toner to printing paper by an intermediate transfer member, and fixes the toner transferred to the printing paper by a fixing device; A laser light source that emits infrared laser light is disposed at a position facing the surface of the body at an angle, and a position where the laser light emitted from the laser light source and reflected by the intermediate transfer body is detected at two positions. A detection element is provided, and two detection positions by this position detection element
An electrophotographic apparatus, further comprising an adhesion amount detecting means for detecting an adhesion amount of the toner transferred to the intermediate transfer member from an interval of (a) . 2. The surface of a photoreceptor is uniformly charged by discharging of a charger, and the surface of the charged photoreceptor is selectively neutralized by exposure of an exposing device to form an electrostatic latent image. In an electrophotographic apparatus in which an electrostatic latent image is developed with toner supplied from a developing device, the toner is transferred to a printing paper, and then fixed by a fixing device, the electrophotographic image is inclined and opposed to the surface of the printing paper on which the toner is transferred. The infrared laser light
A laser light source for emitting light is arranged, and two positions of the laser light emitted from the laser light source and reflected by the printing paper are determined.
The position detecting device for detecting at providing, in the position detecting device
An electrophotographic apparatus, further comprising an adhesion amount detection unit for detecting an adhesion amount of the toner transferred to the printing paper from an interval between the two detection positions . 3. The surface of the photoreceptor is uniformly charged by discharging of a charger, and the surface of the charged photoreceptor is selectively discharged by exposure of an exposing device to form an electrostatic latent image. In an electrophotographic apparatus in which an electrostatic latent image is developed with toner supplied from a developing device, and this toner is transferred to printing paper and then fixed by a fixing device, the electrophotographic latent image is obliquely opposed to the surface of the photoconductor on which the toner is transferred. The infrared laser beam
A laser light source for morphism arranged, the position of the laser beam reflected by the photosensitive member is emitted from the laser light source is provided the position detecting element for <br/> detected at two locations, according to the position detection element
An electrophotographic apparatus, further comprising an adhesion amount detecting unit for detecting an adhesion amount of the toner transferred to the photoconductor from an interval between two detection positions .