JPH10153743A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which can separate and detect laser beams synchronously with a simple mechanism. SOLUTION: This image forming device A records lines on a photosensitive drum 5 at the same time, by scanning a storage medium consisting of a cylindrical photosensitive drum 5 with at least two laser beams L1 and L2 at the same time in the horizontal scanning direction. In this case, a ring-shaped reflection part 5b which reflects the laser beams L1 and L2 by a convex surface is provided at one cylindrical end part of the photosensitive drum 5, and a 1st photodiode 6a for synchronous detection and a 2nd photodiode 6b for synchronous detection are arranged on the optical paths of reflected lights of the laser beams L1 and L2 as detecting means which detect the reflected lights. The reflection part 5b is formed of a photosensitive material uncoated part of the cylindrical end part of the photosensitive drum or by machining the cylindrical end part into a mirror surface.

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, and more particularly to a laser printer, a laser facsimile,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus incorporated in a laser copying machine or the like to simultaneously scan a recording medium in parallel with a main scanning direction with a plurality of recording light beams and record a plurality of lines simultaneously.

[0002]

2. Description of the Related Art An image forming apparatus for recording image information by deflecting a laser beam (light beam) modulated on the basis of an image signal by a rotary polygon mirror or the like and scanning the same on a recording medium is disclosed. Conventionally, it has been incorporated into laser printers, laser facsimile machines, laser copiers, etc., but as such an image forming apparatus, in order to speed up recording, a plurality of laser beams are used to simultaneously scan on a recording medium, and A configuration for recording lines almost simultaneously is known.

However, when a plurality of laser beams are scanned at the same time, the scanning position of each of the plurality of laser beams may be shifted in the main scanning direction or the sub-scanning direction, thereby impairing faithful image formation. Therefore, a configuration has been attempted in which a gap between a plurality of laser beams is detected and dealt with. As such a configuration, for example, two sensors are used, a laser beam is incident on each of these sensors, and the sub-scanning direction of the two laser beams is determined based on the time difference between the incident laser beams on the two sensors. That detects the gap in the distance between the two.

An example of such a configuration, which has already been disclosed, is as follows:
FIG. 9 is based on JP-A-7-72399. In the image exposure system of a laser printer, which is an example of a conventional image forming apparatus, shown in FIG. 1, a laser printer P includes two laser beams (light beams) L1 internally modulated according to image data. L2 is scanned in parallel with the main scanning direction, and two lines are simultaneously recorded on the photosensitive drum (recording medium) 5.

The light source unit 1 has two laser diodes 1a and 1b arranged in a line. The two light beams emitted from the light source unit 1 are converted into two parallel laser beams L1 and L2 by the condenser lens 2. These two laser beams L1 and L2 are applied to the polygon mirror 3, and the two laser beams L1 and L2 deflected by the polygon mirror 3 form an imaging optical system (f
The image is scanned on a photosensitive drum (recording medium) 5 via a θ lens 4.

The photosensitive drum 5 emits a laser beam L1,
The laser beams L1 and L2 and the photosensitive drum 5 are relatively rotated in the sub-scanning direction (a direction orthogonal to the main scanning direction) in rotation in synchronization with the main scanning of L2, thereby recording a two-dimensional image. Is performed. As described above, exposure corresponding to image data is performed simultaneously on two lines, and an electrostatic latent image is formed on the photosensitive drum 5 (recording medium).

The electrostatic latent image is developed with toner of opposite polarity attached thereto, and then the recording paper is superimposed on the toner image. Corona charging polarity is applied from the back side of the recording paper by a corona charger. The toner image is transferred to the recording paper by applying a charge of the opposite polarity to the recording paper.

[0008] The scanning start point of the laser beams L1 and L2 deflected by the polygon mirror 3 is detected by an index sensor 6 disposed at the leading end of the scanning area. When the laser beam L1 or L2 is applied to the tip of the scanning line, the reflecting mirror 7
1, for guiding L2 to the index sensor 6. Here, the index sensor 6 has a special structure composed of a plurality of detection elements.

The following operation is performed in the device having the above configuration. First, only the first laser beam L1 is turned on, and scanning is performed in the same manner as during normal image recording. Then, the first time (detection time difference) T1 from the rising of the beam detection to the rising when only the first laser beam L1 scans on the index sensor 6 is measured.

Next, only the second laser beam L2 is turned on, and scanning is performed in the same manner as during normal image recording. And
Only the second laser beam L2 is emitted from the index sensor 6
A second time (detection time difference) T2 from the rising of the beam detection to the rising when scanning the upper side is measured.

Next, the amount of deviation of the interval between the first laser beam L1 and the second laser beam L2 is calculated based on the difference between the first time T1 and the second time T2 obtained as described above. , An adjustment mechanism (eg, a stepping motor) is driven to adjust the position in the sub-scanning direction.

[0012]

As described above, an image for recording image information by scanning a recording medium by deflecting and scanning a laser beam modulated based on an image signal by a rotary polygon mirror or the like. In the forming apparatus, in order to achieve high-speed recording, a configuration in which a plurality of lines are simultaneously recorded using a plurality of laser beams is suitable, and a case in which a plurality of laser beams are simultaneously scanned as in the above-described configuration. In this case, it is necessary to synchronize the respective beams so that the writing position is accurately adjusted.

However, the method described in Japanese Patent Application Laid-Open No. 7-7239
No. 9) uses a sensor having a special structure in which the inside is composed of a plurality of detection elements. First, only one first laser beam is incident on the sensor, and
The time is detected, and then only one second laser beam is incident on the sensor to detect the second time. Based on the difference between the first time and the second time obtained in this manner, 2 is detected. Since the writing position is controlled by detecting the gap between the laser beams in the sub-scanning direction, the laser beam switching control and expensive sensors with special structures are required. Since the number of times is twice, there is a disadvantage that the cost and the required time are disadvantageous.

Therefore, various proposals for configurations other than those described above have been tried, but there is a problem that it is difficult to independently detect each light beam due to a narrow interval between laser beams. Did not reach.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made to solve the problems in the prior art, and proposes an image forming apparatus capable of synchronizing detection by separating a light beam of a laser beam by a simple mechanism. It is intended to be. Alternatively, it is another object of the present invention to propose a light beam separation optical system capable of performing synchronous detection at two points. Further, it is another object of the present invention to propose a light beam separation optical system having a small light amount loss.

[0016]

According to a first aspect of the present invention, there is provided an image forming apparatus, wherein at least two laser beams simultaneously scan a storage medium in parallel with a main scanning direction. An image forming apparatus configured to simultaneously record a plurality of lines on the storage medium, wherein the storage medium includes a cylindrical photosensitive drum, and at least one end of the photosensitive drum includes A ring-shaped reflecting portion for reflecting a laser beam by a convex surface is provided, and a detecting means for detecting the reflected light is provided on an optical path of each reflected light of each laser beam.

According to the image forming apparatus of the present invention having the above-described configuration, the convex reflection surface of the annular reflection portion at the end of the photosensitive drum significantly affects the optical path of each reflected light of each laser beam. A difference is formed, so that the light beam of the laser beam is separated by a simple mechanism, and the synchronous detection is facilitated. In addition, since the synchronous detection of each laser beam is performed at the same time, the time is reduced and high-speed adjustment is realized.

Further, in the image forming apparatus according to the present invention (claim 2), the annular reflecting portion at the end of the photosensitive drum is formed by a photosensitive material non-coated portion at the end of the photosensitive drum. It is characterized by the following. According to the above configuration, it is easy to form a ring-shaped reflecting portion on the photosensitive drum, and the cost is reduced.

Alternatively, in the image forming apparatus according to the present invention, the annular reflecting portion at the end of the photosensitive drum is formed by mirror-finishing the end of the photosensitive drum. Features. According to the above configuration, the reflection efficiency is improved, and thus the loss of light amount is reduced, and the detection sensitivity is improved.

Further, the image forming apparatus according to the present invention (claim 4) is characterized in that a reflected light focusing system is disposed between the reflecting section and the detecting means for detecting reflected light.
According to the above configuration, the light collection efficiency of the reflected light is improved, and thus the detection sensitivity of the reflected light is improved.

Alternatively, the image forming apparatus according to the present invention is characterized in that the reflected light condensing system is constituted by an anamorphic lens having different curvatures in the main scanning direction and the sub-scanning direction. The anamorphic lens improves the light collection efficiency of the reflected light, thereby improving the detection sensitivity of the image forming apparatus.

Further, an image forming apparatus according to the present invention (Claim 6) is an endless photosensitive belt which performs substantially the same operation as the photosensitive drum in the image forming apparatus according to the first embodiment. Is provided.

That is, the image forming apparatus is configured to simultaneously record a plurality of lines on the storage medium by scanning at least two laser beams simultaneously on the storage medium in parallel with the main scanning direction. And
The storage medium is composed of an endless photoreceptor belt, and one end or both ends (one end or both ends in the width direction) of the photoreceptor belt has a ring-shaped reflection for reflecting the laser beams by a convex surface. And a detecting means for detecting the reflected light on the optical path of the reflected light of each of the laser beams.

According to the image forming apparatus having the above-described configuration, each of the reflected lights of the laser beams is reflected by the convex reflecting surface of the annular reflecting portion at the end of the photosensitive belt (the end in the width direction, the same applies hereinafter). A significant difference is formed in the optical path, so that the light beam of the laser beam is separated by a simple mechanism, and the synchronous detection is facilitated. In addition, since the synchronous detection of each laser beam is performed at the same time, the time is reduced and high-speed adjustment is realized.

Further, in the image forming apparatus according to the present invention (claim 7), the annular reflecting portion at the end of the photosensitive belt is formed by a photosensitive material non-coating portion at the end of the photosensitive belt. It is characterized by the following. According to the above configuration, it is easy to form a ring-shaped reflecting portion on the photoreceptor belt, and the cost is reduced.

Alternatively, in the image forming apparatus according to the present invention (claim 8), the annular reflecting portion at the end of the photoreceptor belt is formed by mirror-finishing the end of the photoreceptor belt. Features. According to the above configuration, the reflection efficiency is improved, and thus the loss of light amount is reduced, and the detection sensitivity is improved.

Furthermore, an image forming apparatus according to the present invention (claim 9) is characterized in that a reflected light condensing system is disposed between the reflecting section and the detecting means for detecting reflected light.
According to the above configuration, the light collection efficiency of the reflected light is improved, and thus the detection sensitivity of the reflected light is improved.

Alternatively, the image forming apparatus according to the present invention is characterized in that the reflected light condensing system is constituted by an anamorphic lens having different curvatures in the main scanning direction and the sub-scanning direction. The anamorphic lens improves the light collection efficiency of the reflected light, thereby improving the detection sensitivity of the image forming apparatus.

[0029]

Embodiments of the present invention will be described below. Embodiment 1 FIG. 1 is a perspective view showing an optical system of a laser printer as a configuration in an embodiment of a main optical system of an image forming apparatus according to the present invention.

An image forming apparatus A according to the present invention includes a light source unit 1 in which two first laser diodes 1a and a second laser diode 1b are arranged in a line, and two systems emitted from the light source unit 1. A condenser lens 2 for converting the divergent light into two parallel laser beams L1 and L2; a polygon mirror 3 for deflecting the two laser beams L1 and L2 emitted from the condenser lens 2 by rotation; An imaging optical system 4 composed of an fθ mirror or the like and configured to image the two laser beams L1 and L2 deflected by the polygon mirror 3, and a photosensitive material (recording) on substantially the entire outer peripheral surface of the cylindrical photosensitive drum 5. Material) coating,
A plurality of lines are formed at one end of a photosensitive drum 5 and a photosensitive material coating portion 5a on which a plurality of lines are simultaneously recorded by simultaneously scanning the two laser beams L1 and L2 in parallel with the main scanning direction. Due to the convex surface, two laser beams L1
A ring-shaped reflecting portion 5b for reflecting the light beams L1 and L2, and the reflected lights L1r and L2r of the two laser beams L1 and L2 (FIG. 2)
And a second synchronous detection second photodiode 6a, which is disposed on the optical path of FIG.
And a photodiode 6b.

In the present embodiment, two laser beams modulated by the image information and emitted from the light source unit 1 are converted into two parallel laser beams L by the condenser lens 2.
1 and L2, these two laser beams L1 and L2 are deflected by the polygon mirror 3, imaged on the photosensitive drum 5 via the imaging optical system 4, and scanned in parallel with the main scanning direction to form two lines. Write at the same time.

The main part of the present invention is the annular reflector 5b provided at the end of the photosensitive drum, noting that the photosensitive drum 5 is cylindrical. FIG. 2 is a diagram illustrating this configuration principle. As shown in the figure, the annular reflecting portion 5b according to the present invention is provided at the end of the photosensitive drum 5, the photosensitive member is not coated (photosensitive material non-coated portion), and Using the convex surface that reflects light as a reflective surface,
The two laser beams L1 and L2 are reflected in directions greatly different from each other by the curvature of the convex surface, and the two reflected lights L1r and L2r whose directions are separated in this way are disposed on respective optical paths. The configuration is such that the light is guided to the first photodiode 6a for synchronization detection and the second photodiode 6b for synchronization detection.

As described above, the two laser beams incident on the photosensitive drum in parallel have the effect that the optical paths of the respective reflected lights are clearly separated due to the effect of the convex reflection surface, so that the synchronous detection becomes extremely easy. Is used.

An annular reflector 5b at the tip of the photosensitive drum 5
Can be formed by using the uncoated portion of the photosensitive material at the end of the photosensitive drum as it is, but is preferably formed by mirror finishing the end of the photosensitive drum. By mirror-finishing the reflecting portion in this way, the reflectance is increased and the light amount loss is reduced.

As shown in FIG. 2, the reflecting portion 5b
And a first reflected light condensing lens 7a and / or a second reflected light condensing lens 7b as a reflected light condensing system between the first synchronous detection photodiode 6a and / or the second synchronous detection photodiode 6b. It can also be provided. These reflected light condensing lenses condense the divergent luminous flux by reflecting on the convex reflecting surface of the photoconductor drum, so that the loss of light amount can be reduced.

In particular, the first reflected light focusing lens 7
It is preferable that the lens a and the second reflected light condensing lens 7b are constituted by a cylinder lens, an anamorphic lens, or the like having different curvatures in the main scanning direction and the sub-scanning direction.

Embodiment 2 FIG. 3 is a perspective view of the configuration of another embodiment of the image forming apparatus according to the present invention. In the image forming apparatus A2 of this embodiment, the reflecting portions are provided at both ends of the photosensitive drum 5, such as the photosensitive drum front-end reflecting portion 5c and the photosensitive drum rear-end reflecting portion 5d. Further, a first tip photodiode 6c and a second tip photodiode 6d are provided corresponding to the photosensitive drum front-end reflecting portion 5c.
By providing the rear-end first photodiode 6e and the rear-end second photodiode 6f corresponding to d, two-point synchronization becomes possible, and a configuration advantageous for high accuracy is obtained.

As described above, in the image forming apparatus according to the present invention, since the synchronous detection of each laser beam can be performed simultaneously, the time is shortened as compared with the prior art.

Third Embodiment FIG. 4 is a perspective view showing an optical system of a laser printer as a configuration of one embodiment of a main optical system of an image forming apparatus according to the present invention. The image forming apparatus A3 includes a photosensitive drum 5 having a predetermined configuration according to the first embodiment shown in FIG.
A photoreceptor belt 15 having the following configuration is provided instead of a, and the other configuration is the same as that of FIG. The operation of the image forming apparatus is the same as that of the first embodiment.

That is, the photosensitive material (recording material) is coated on almost the entire surface of the endless photosensitive belt 15 wrapped around the rollers 17a and 17b and circulated by these rollers. A portion 15a is formed. Then, by scanning the two laser beams L1 and L2 simultaneously in parallel with the main scanning direction, a plurality of lines are simultaneously recorded on the photosensitive material coating unit 15a. Further, a ring-shaped reflecting portion 15b (photosensitive material non-coated portion) is formed at one end of the photoreceptor belt 15, and the convex surfaces thereof reflect two laser beams L1 and L2. Furthermore, the respective reflected lights L1 of the two laser beams L1 and L2
r and L2r (see FIG. 5), a synchronous detection first photodiode 6a serving as reflected light detection means, which is disposed on the optical path.
And a synchronous detection second photodiode 6b.

In this image forming apparatus, the photosensitive belt 15
Is wound around the cylindrical roller 17a, so that the U-turn portion 16 of the photoreceptor belt 15 has a cylindrical shape (a portion where the belt is in contact with the roller). The annular reflector 15b provided at the end of the belt
There is the main part. FIG. 5 is a diagram for explaining the configuration principle.

As shown in FIG.
“b” is provided at the end of the photoreceptor belt 15, the photosensitive material is not coated (photosensitive material non-coated portion), and a convex surface that reflects light is used as a reflective surface, and the convex surface has a curvature. Reflects the two laser beams L1 and L2 in directions that are greatly different from each other.
The configuration is such that the reflected lights L1r and L2r are guided to the first synchronous detection photodiode 6a and the second synchronous detection photodiode 6b disposed on the respective optical paths.

An annular reflector 15 at the tip of the photoreceptor belt 15
b can be formed by using the photosensitive material non-coated portion at the end of the photoreceptor belt as it is, but is preferably formed by mirror-finishing the end of the photoreceptor belt. By mirror-finishing the reflecting portion in this way, the reflectance is increased and the light amount loss is reduced.

Also, as shown in FIG. 5, as shown in FIG. 5, the reflection section 15b, the first synchronous detection photodiode 6a and / or the second synchronous detection photodiode 6
b, a first reflected light focusing lens 7a and / or a second reflected light focusing lens 7b may be provided as a reflected light focusing system. These reflected light condensing lenses condense the divergent light flux by reflecting on the convex reflection surface of the photoreceptor belt, so that the loss of light amount can be reduced.

In particular, the first reflected light focusing lens 7
It is preferable that the lens a and the second reflected light condensing lens 7b are constituted by a cylinder lens, an anamorphic lens, or the like having different curvatures in the main scanning direction and the sub-scanning direction.

Embodiment 4 In the image forming apparatus of the present invention, as shown in FIG. 6, the diameter of the roller 17a for traveling the photoreceptor belt is made smaller than that of the roller 17b, so that the power of the convex of the reflecting surface can be freely adjusted. And the separation of the laser beam becomes easier than the photosensitive drum.

Embodiment 5 Further, in the image forming apparatus of the present invention, as shown in FIG. 7, an auxiliary roller 17c for forming a convex reflecting surface can be provided between the rollers 17a and 17b. In this case, there is an advantage that the layout of the image forming apparatus is facilitated.

Embodiment 6 FIG. 8 is a perspective view showing the structure of still another embodiment of the image forming apparatus according to the present invention. In the image forming apparatus A4 of this embodiment, the reflection portions are provided at both ends of the photoconductor belt 15, such as the photoconductor belt front-end reflection portion 15c and the photoconductor belt rear-end reflection portion 15d. Further, a first tip photodiode 6c and a second tip photodiode 6d are provided corresponding to the photoconductor belt tip reflector 15c, and a trailing first photodiode 6e and a tip photodiode 6e corresponding to the photoconductor belt trailer reflector 15d. By providing the rear end second photodiode 6f, two-point synchronization is possible, which is a configuration advantageous for high accuracy.

[0049]

As described in detail above, claim 1 of the present invention
The image forming apparatus according to the above is an image forming apparatus having a configuration in which a plurality of lines are simultaneously recorded on the storage medium by simultaneously scanning at least two laser beams on the storage medium in parallel with the main scanning direction, The storage medium is constituted by a cylindrical photosensitive drum, and at least one end of the photosensitive drum is provided with a ring-shaped reflecting portion for reflecting each of the laser beams by a convex surface. Since the detecting means for detecting the reflected light is disposed on the optical path of the light, each of the laser beams is formed by the convex reflecting surface of the annular reflecting portion at the end of the photosensitive drum. A significant difference is formed in the optical path of the reflected light, so that a remarkable beam separation of the laser beam can be performed with a simple mechanism, and easy synchronous detection can be performed at low cost. In addition, since synchronous detection of each laser beam can be performed simultaneously, the time can be reduced.

Furthermore, particularly, by providing the reflecting portions at both ends of the front end and the rear end of the photosensitive drum, two-point synchronization can be detected, and the accuracy can be improved.

An image forming apparatus according to a second aspect of the present invention comprises:
Since the annular reflecting portion at the end of the photosensitive drum is formed by the photosensitive material non-coating portion at the end of the photosensitive drum, the annular reflecting portion on the photosensitive drum is The formation is easy, and the processing cost can be reduced.

According to a third aspect of the present invention, there is provided an image forming apparatus comprising:
Since the annular reflecting portion at the end of the photoconductor drum is formed by mirror-finishing the end of the photoconductor drum, the reflection efficiency is improved, and thus the detection sensitivity is improved due to a decrease in light amount loss. There is an effect that can be.

An image forming apparatus according to a fourth aspect of the present invention comprises:
Since the reflected light condensing system is disposed between the reflecting section and the detecting means for detecting the reflected light, the reflected light condensing system improves the efficiency of condensing the reflected light, and thus detects the reflected light. Sensitivity can be improved.

According to a fifth aspect of the present invention, there is provided an image forming apparatus comprising:
Since the reflected light condensing system is constituted by an anamorphic lens having different curvatures in the main scanning direction and the sub-scanning direction, the anamorphic lens improves the efficiency of condensing the reflected light, and thus the detection sensitivity of the image forming apparatus. There is an effect that can be improved.

An image forming apparatus according to a sixth aspect of the present invention comprises:
By providing a photoreceptor belt having a predetermined configuration in place of the photoreceptor drum according to the first aspect, excellent operational effects can be obtained as in the apparatus of the first aspect.

In particular, by providing the reflecting portions at both ends of the front end and the rear end of the photoreceptor belt, two-point synchronization can be detected, and the accuracy can be improved.

According to a seventh aspect of the present invention, there is provided an image forming apparatus comprising:
Since the annular reflecting portion at the end of the photoreceptor belt is formed by a non-coated photosensitive material portion at the end of the photoreceptor belt, the annular reflecting portion on the photosensitive belt is The formation is easy, and the processing cost can be reduced.

An image forming apparatus according to claim 8 of the present invention provides:
Since the annular reflecting portion at the end of the photoreceptor belt is formed by mirror-finishing the end of the photoreceptor belt, the reflection efficiency is improved, and thus the detection sensitivity is improved due to a decrease in light amount loss. There is an effect that can be.

According to the ninth aspect of the present invention, there is provided an image forming apparatus comprising:
Since the reflected light condensing system is disposed between the reflecting section and the detecting means for detecting the reflected light, the reflected light condensing system improves the efficiency of condensing the reflected light, and thus detects the reflected light. Sensitivity can be improved.

In the image forming apparatus according to a tenth aspect of the present invention, the reflected light condensing system is constituted by an anamorphic lens having different curvatures in the main scanning direction and the sub-scanning direction. There is an effect that the light collection efficiency is improved, and thus the detection sensitivity of the image forming apparatus can be improved.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a configuration principle of the image forming apparatus of FIG.

FIG. 3 is a perspective view illustrating a configuration of another embodiment of the image forming apparatus.

FIG. 4 is a perspective view illustrating a configuration of still another embodiment of the image forming apparatus.

FIG. 5 is a diagram illustrating a configuration principle of the image forming apparatus of FIG. 4;

FIG. 6 is a schematic side view illustrating a configuration of still another embodiment of the image forming apparatus.

FIG. 7 is a schematic side view illustrating a configuration of still another embodiment of the image forming apparatus.

FIG. 8 is a perspective view illustrating a configuration of still another embodiment of the image forming apparatus.

FIG. 9 is a perspective view illustrating a configuration of a conventional image forming apparatus.

[Explanation of symbols]

 A, A2, A3, A4 Image forming apparatus P Laser printer 1 Light source unit 1a First laser diode 1b Second laser diode 2 Condensing lens 3 Polygon mirror 4 Image forming optical system 5 Photoconductor drum 5a, 15a Photosensitive material coating unit 5b, 15b Reflecting portion (photosensitive material non-coated portion) 5c Photosensitive drum front-end reflecting portion 5d Photosensitive drum rear-end reflecting portion 6 Index sensor 6a Synchronous detection first photodiode 6b Synchronous detection second photodiode 6c Tip first photo Diode 6d Front end second photodiode 6e Rear end first photodiode 6f Rear end second photodiode 7a First reflected light condenser lens 7b Second reflected light condenser lens 15 Photoconductor belt 15c Photoconductor belt front reflector 15d Photosensitive Body belt rear end reflection section 16 You-turn section 17a, 17b Roller Photoreceptor belt traveling) 17c auxiliary roller (convex reflecting surface formed)

Claims (10)

[Claims] 1. At least two laser beams simultaneously scan a storage medium in parallel with a main scanning direction,
An image forming apparatus configured to simultaneously record a plurality of lines on the storage medium, wherein the storage medium includes a cylindrical photosensitive drum, and each of the laser beams is provided on at least one end of the photosensitive drum. An image forming apparatus, comprising: a ring-shaped reflecting portion that reflects light by a convex surface; and a detecting unit that detects the reflected light on an optical path of each reflected light of each of the laser beams. 2. The image forming apparatus according to claim 1, wherein the annular reflecting portion at the end of the photosensitive drum is formed by a photosensitive material non-coating portion at the end of the photosensitive drum. 3. The image forming apparatus according to claim 1, wherein the annular reflecting portion at the end of the photoconductor drum is formed by mirror finishing the end of the photoconductor drum. 4. An image forming apparatus according to claim 1, wherein a reflected light condensing system is disposed between said reflecting portion and said detecting means for detecting reflected light. 5. The image forming apparatus according to claim 4, wherein the reflected light condensing system includes an anamorphic lens having different curvatures in a main scanning direction and a sub-scanning direction. 6. At least two laser beams simultaneously scan a storage medium in parallel with a main scanning direction.
An image forming apparatus configured to simultaneously record a plurality of lines on the storage medium, wherein the storage medium is formed of an endless photoreceptor belt, and at least one end of the photoreceptor belt width direction includes the Image forming, wherein a ring-shaped reflecting portion for reflecting the laser beam by a convex surface is provided, and a detecting means for detecting the reflected light is provided on an optical path of each reflected light of each of the laser beams. apparatus. 7. The image forming apparatus according to claim 6, wherein the annular reflecting portion at the end of the photoreceptor belt is formed by a non-coated photosensitive material portion at the end of the photoreceptor belt. 8. The image forming apparatus according to claim 6, wherein the annular reflecting portion at the end of the photoreceptor belt is formed by mirror finishing the end of the photoreceptor belt. 9. An image forming apparatus according to claim 6, wherein a reflected light condensing system is disposed between said reflecting portion and said detecting means for detecting reflected light. 10. The image forming apparatus according to claim 9, wherein the reflected light condensing system includes an anamorphic lens having different curvatures in a main scanning direction and a sub-scanning direction.