JP2013117569A - Optical scanning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanning device which is high in reliability by suppressing the deterioration of image quality even in the case of its long time use in an environment with many dusts.SOLUTION: The optical scanning device includes a partition part (compound lens member 44 and protrusion 57a arranged in lid 57) for parting a space formed of an optical box 50 and a lid 57, that is, a space where a rotary polygon mirror 45 and a slit edge part 50b exist, between the rotary polygon mirror 45 and the slit edge part 50b.

Description

  The present invention relates to an optical scanning device that has a function of forming an image on a recording material such as a sheet, and performs optical writing using a laser beam in an image forming apparatus such as a copying machine or a printer.

Conventionally, an optical scanning device used in an image forming apparatus such as a laser printer performs the following operation. In other words, a plurality of laser beams emitted from light sources modulated and emitted from a light source unit according to an image signal are deflected and scanned by a deflecting unit, and the deflected and scanned laser beams are scanned on a photosensitive drum by a scanning lens (fθ lens) having fθ characteristics. Is imaged. Thereby, an electrostatic latent image is formed on the photosensitive drum.
Thereafter, in the image forming apparatus, the electrostatic latent image on the photosensitive drum is visualized as a toner image by a developing device, transferred to a recording material and sent to a fixing device, and the toner image on the recording material is heated and fixed. Printing (printing, image formation) is performed at.
Further, a condensing lens, a signal detection defining portion, and a signal detection sensor are sequentially provided on the optical path of the laser light beam deflected and scanned outside the effective image area of the photosensitive drum. The laser beam enters the condenser lens immediately before deflecting and scanning the fθ lens, is condensed on the signal detection defining portion, and is scanned in the main scanning direction and passes through the signal detection defining portion. To reach. When the laser beam reaches the signal detection sensor, a reference signal for synchronizing the writing position in the main scanning direction on the photosensitive drum is generated. This reference signal is similarly generated for each of the plurality of laser beams. The signal detection defining unit is disposed at a substantially condensing position of the condensing lens in order to more accurately detect the timing at which the laser beam reaches the signal detection sensor (see, for example, Patent Document 1).

JP 2003-121771 A

However, since the laser beam is condensed on the signal detection defining portion in the conventional example, the following is a concern.
When the image forming apparatus is used for many years in a dusty environment, there is a concern that dust may adhere to the signal detection defining portion. The particle size of dust floating in the air varies, and is generally said to be about 0.01 μm to 100 μm. However, according to the study by the present inventors, the particle size of the dust adhering to components other than the rotary polygon mirror in the optical scanning device is not so high, and almost 1 to 30 μm. The spot diameter of the laser beam on the signal detection defining portion is approximately 20 μm when the spot diameter on the photosensitive drum is about 70 μm and the focal length of the condenser lens is about 1/3 of the focal length of the fθ lens.
For example, when two-line scanning is performed in one scan using a semiconductor laser having two light emitting points, the two laser light beams SA and SB are different in the sub-scanning direction by the signal detection defining unit 102 as shown in FIG. Scanning is performed at a different position. In this case, if dust D having a particle size of 30 μm adheres to a location where one laser beam SB of the signal detection defining unit 102 scans, the timing at which the laser beam is blocked by dust and enters the signal detection sensor 101 is delayed by about 30 μm. Will do.
FIG. 14 is a diagram illustrating a timing chart of signals corresponding to FIG. 13 in which two laser light beams SA and SB are detected by the signal detection sensor. FIG. 14A shows a normal timing chart, and FIG. 14B shows a timing chart when dust adheres to the signal detection defining portion. When the detection operation is performed by the signal detection sensor 101, the output voltage of the sensor drops by ΔV. At that time, the writing position in the main scanning direction on the photosensitive drum is determined. The time ΔT′−ΔT shown is equivalent to scanning a distance of 30 μm.
Further, when the delay of 30 μm is converted into the amount of dot position deviation in the main scanning direction on the photosensitive drum, the dot position deviation is about three times, that is, about 90 μm, due to the focal length relationship between the condenser lens and the fθ lens. . The relative dot position deviation amount in the main scanning direction of a plurality of laser beams on the photosensitive drum is, for example, when an image is formed at a recording density of 600 dpi, if the deviation amount exceeds 1/3 dots, a smooth line is formed. It becomes difficult and the image quality deteriorates.
Therefore, if dust having a particle diameter of 30 μm adheres to a portion where one laser beam of the signal detection defining portion scans, the relative dot position deviation amount on the photosensitive drum becomes about 90 μm, and the image quality may be significantly deteriorated. There is. As described above, there is a concern that if the dust adheres to the signal detection defining portion, it becomes a very big problem. Further, when one line scan is performed by one scan using one light beam, the image writing position is shifted as a whole, and there is a concern that a problem of deterioration in image quality may occur.

  The present invention has been made in view of the circumstances as described above, and an object of the present invention is to provide a highly reliable optical scanning device that suppresses deterioration in image quality even when used for many years in a dusty environment. To do.

In order to achieve the above object, the present invention provides:
A deflection scanning means for deflecting and scanning the light beam emitted from the light source by being driven;
An optical scanning device that forms an image of a light beam deflected and scanned by the deflection scanning unit on a scanned object,
In order to determine the position where the light beam deflected and scanned by the deflection scanning means starts scanning on the scanned object, the light beam is detected by being incident before being imaged on the scanned object. Detecting means for
A regulating unit that regulates the optical path of the light beam so that the light beam deflected and scanned by the deflection scanning unit is incident on the detection unit at a preset position;
An optical box in which the deflection scanning unit, the detection unit, and the regulating unit are disposed;
A lid covering the optical box;
In an optical scanning device comprising:
It is characterized by comprising a partition part for partitioning the space formed by the optical box and the lid in which the deflection scanning means and the restriction part exist, between the deflection scanning means and the restriction part. .

  According to the present invention, even when used in a dusty environment for many years, it is possible to provide a highly reliable optical scanning device that suppresses deterioration in image quality.

1 is a schematic perspective view showing an optical scanning device 3 of Embodiment 1. FIG. FIG. 3 is a schematic perspective view illustrating a main part of the optical scanning device 3 according to the first embodiment. 1 is a cross-sectional view of the optical scanning device of FIG. 1 cut along the optical path of laser light L2. The figure showing the numerical analysis result in Example 1 The figure showing the numerical analysis result in Example 1 The top view which showed the principal part of the optical scanning device of Example 1. Sectional drawing which shows schematic structure of the image forming apparatus provided with the optical scanning device of Example 1. Schematic perspective view showing an optical scanning device of Example 2. FIG. Sectional drawing when the optical scanning device of FIG. 8 is cut along the optical path of the laser beam L2. The figure at the time of cutting the optical scanning apparatus of Example 3 along the optical path of the laser beam L2 The figure shown about the structure which provided the elastic member in the apparatus of FIG. The figure at the time of cutting the optical scanning apparatus of Example 4 along the optical path of the laser beam L2 Diagram for explaining the prior art Diagram for explaining the prior art

  DETAILED DESCRIPTION Exemplary embodiments for carrying out the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. It is not intended to limit the scope to the following embodiments.

Example 1 will be described below.
First, the outline of the configuration and operation of the image forming apparatus according to the present embodiment will be described. FIG. 7 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus including the optical scanning device 3 according to the present embodiment. The image forming apparatus of this embodiment is an electrophotographic laser beam printer.

As shown in FIG. 7, a charging roller 2, an optical scanning device 3, a developing device 4, and a cleaning device 5 are disposed around the photosensitive drum 1.
The surface of the photosensitive drum 1 that is uniformly charged by applying a bias voltage from the charging roller 2 is subjected to optical scanning according to image information from the optical scanning device 3, so that the photosensitive drum 1 as a scanned body is electrostatically applied. A latent image is formed. The latent image is developed with a toner by the developing device 4 to be visualized. The visualized toner image is obtained by applying a bias voltage to the transfer roller 7 when the recording material P conveyed by the conveyance roller 6 is conveyed to the nip portion between the photosensitive drum 1 and the transfer roller 7. Transferred to the recording material P.

  The recording material P to which the toner image has been transferred is conveyed to the fixing device 8, and after the toner is fixed by the fixing device 8, the recording material P is discharged to a discharge portion 9 at the top of the apparatus. On the other hand, the toner remaining on the photosensitive drum 1 after the transfer of the toner image to the recording material P is removed by the cleaning device 5.

Next, the overall configuration of the optical scanning device 3 will be described.
FIG. 1 is a schematic perspective view showing an optical scanning device 3 according to this embodiment. FIG. 2 is a schematic perspective view illustrating a main part of the optical scanning device 3 according to the present embodiment.
As shown in FIGS. 1 and 2, in the optical scanning device 3, the semiconductor laser 41 is incorporated into the laser support member 42 by press fitting or the like, and is soldered to the control board 43 and electrically connected thereto. The semiconductor laser 41 is a laser light source that emits a laser beam (light beam) L1 modulated according to image information.

The laser light L1 emitted from the semiconductor laser 41 passes through the lens 44a of the compound lens member 44 that is bonded and fixed in advance to the optical box 50 as a housing. As a result, the laser light L1 is converted into parallel light, desired convergent light, or divergent light in the main scanning direction, and the rotating polygon mirror 45 in the sub-scanning direction orthogonal to the scanning direction of the laser light L1. A linear image is formed on the reflecting surface of the lens.
An aperture stop 50a is disposed between the compound lens member 44 and the rotary polygon mirror 45 to limit the light beam of the laser light L1. Here, the rotary polygon mirror 45 corresponds to a deflection scanning unit that deflects and scans the laser beam L1 from the semiconductor laser 41 by being driven.

The laser beam L1 reflected and deflected by the rotary polygon mirror 45 passes through a scanning lens 47 having a so-called fθ characteristic, is reflected by a folding mirror 48, and forms an image on the photosensitive drum 1 (on the object to be scanned). The rotary polygon mirror 45 is driven at high speed by being driven by the drive motor 46 and scans the photosensitive drum 1 with laser light. At this time, the scanned laser light moves on the photosensitive drum 1 at a constant speed, so that a latent image is formed on the photosensitive drum 1.

The detection sensor 49 mounted on the control board 43 detects an image writing position. Here, the detection sensor 49 is incident before the laser beam is imaged on the photosensitive drum 1 in order to determine the position where the laser beam deflected and scanned by the rotary polygon mirror 45 starts scanning on the photosensitive drum 1. This corresponds to detection means for detecting the laser beam.
A part of the laser light L2 out of the image area scanned by the rotary polygon mirror 45 is transmitted through the lens 44b of the compound lens member 44, thereby forming an image on the slit edge 50b as a signal detection defining portion. It enters the detection sensor 49. The detection sensor 49 receives the laser beam L2 to generate a horizontal synchronization signal.

  Here, the slit edge portion 50b restricts the optical path of the laser light so that the laser light deflected and scanned by the rotary polygon mirror 45 enters the detection sensor 49 at a preset position (signal detection defining portion). It corresponds to. The lens 44 b corresponds to a condensing member that condenses the laser light deflected and scanned by the rotary polygon mirror 45 on the detection sensor 49. The compound lens member 44 includes a lens 44b and a support member that supports the lens 44b. In the present embodiment, a description will be given of a form using the compound lens member 44 that enables a plurality of functions (functions of the lenses 44a and 44b) with one lens, but the present invention is not limited to this, and the lenses 44a and 44b are different. It may be provided on the body.

  The slit edge portion 50b is disposed immediately before the detection sensor 49 (upstream of the optical path of the laser beam L2), and is provided to accurately detect the writing start timing. In the present embodiment, the slit edge portion 50 b is molded integrally with the optical box 50, but is not limited thereto, and may be separate from the optical box 50. The optical scanning device 3 is configured by covering the optical box 50 in which the above-described components are disposed with a lid 57.

FIG. 3 is a cross-sectional view of the optical scanning device 3 shown in FIG. 1 taken along the optical path of the laser light L2.
As shown in FIG. 3, the space 60 is a space formed by the optical box 50 and the lid 57, and is a space where the rotary polygon mirror 45 exists, and the space 61 is formed by the optical box 50 and the lid 57. It is a space where the slit edge portion 50b exists.
In the present embodiment, a convex portion 57 a as a protruding portion is formed integrally with the lid 57, and the convex portion 57 a is disposed adjacent to (adjacent to) the compound lens member 44. Thus, a space formed by the optical box 50 and the lid 57 and including the rotary polygon mirror 45 and the slit edge portion 50b is partitioned between the rotary polygon mirror 45 and the slit edge portion 50b. (Separated). Thereby, the space 60 and the space 61 are formed. The convex part 57a and the composite lens member 44 constitute a partition part.

Here, when the rotary polygon mirror 45 is driven to rotate, air in the space 60 is agitated to generate airflow. At this time, if the cover 57 is not provided with the convex portion 57a as in the conventional case, the air current passes above the compound lens member 44 and the slit edge portion 50b exists as indicated by the broken line arrow F1 in FIG. Flows into the space 61 to be operated. The airflow flowing into the space 61 is discharged from a minute gap between the detection sensor 49 and the control substrate 43, and directly hits the slit edge 50b in the process.
The state of the airflow varies depending on the internal shape of the optical scanning device 3, the arrangement of the optical components, the presence / absence of the opening of the optical box 50, etc., but the airflow generated in the space 60 enters the optical scanning device 3. There is concern about inducing the inflow of dust. When dust flows in, the space 60 to the space 6
There is a risk that dust will flow in with the airflow flowing into 1, and the dust will adhere to the slit edge 50b. Here, the conventional configuration has been described using the reference numerals of the embodiments for convenience of description.

  In the present embodiment, as shown in FIGS. 3 and 6, the space 57 where the slit edge portion 50b exists is formed by the wall portions 50d and 50e, the composite lens member 44, and the convex portion 57a. , Separated from the space 60 (divided, partitioned). As a result, an airflow as indicated by an arrow F1 indicated by a broken line in FIG. 3 can be suppressed. Therefore, the space 61 has a higher degree of sealing than the space 60, and the inflow of dust into the space 61 can be suppressed. FIG. 6 is a plan view showing a main part of the optical scanning device 3.

Here, it is preferable that the convex portion 57a and the compound lens member 44 are arranged without a gap. However, since the lid 57 is a molded product, a gap exists due to problems such as dimensional tolerance and assemblability.
In view of this, the present inventor conducted a numerical analysis and studied the state of the airflow from the composite lens member 44 to the slit edge portion 50b when there is a gap between the convex portion 57a and the composite lens member 44.
4 and 5 are diagrams showing the results of numerical analysis of the state of airflow from the compound lens member 44 to the slit edge portion 50b. FIG. 4 shows a case where the convex portion 57a is not provided, and FIG. 5 shows a case where the convex portion 57a is provided. The direction indicated by each vector in the figure indicates the direction in which air flows. Moreover, the white part 58 of the vector in the figure has shown the location where the speed of airflow is quick.

Table 1 below shows the flow rate and the maximum flow velocity that pass through the opening 50c in the vicinity of the slit edge 50b.

  According to Table 1, it can be seen that by providing the convex portion 57a, both the flow rate and the maximum flow velocity of the opening 50c are approximately halved compared to the case where the convex portion 57a is not provided. That is, it turns out that the airflow which directly hits the slit edge part 50b can be suppressed. This is because the configuration in which the convex portion 57a is provided adjacent to the compound lens member 44 narrows the flow path through which the air flow generated by the rotation of the rotary polygon mirror 45 flows from the space 60 to the space 61, and further bends the flow path. By doing so, it is considered that the airflow flowing into the space 61 was suppressed.

  As described above, according to the present embodiment, by separating the space 60 in which the rotary polygon mirror 45 is present and the space 61 in which the slit edge portion 50b is present, airflow is prevented from flowing into the slit edge portion 50b. Can do. As a result, it is possible to suppress the dust from adhering to the slit edge portion 50b, so that the delay of the signal detection timing caused by the dust adhering to the slit edge portion 50b is reduced, and the relative dot shift on the photosensitive drum is reduced. The amount can be reduced. Therefore, even when used in a dusty environment for many years, it is possible to reduce image quality degradation as much as possible, and to provide a highly reliable optical scanning device.

Here, in the present embodiment, the convex portion 57a is disposed adjacent to the right side of FIG. 3 (downstream of the optical path of the laser light L2) with respect to the compound lens member 44 (aligned in the optical axis direction shown in FIG. 3). In the case described in FIG. However, the positional relationship of the convex portion 57a with respect to the composite lens member 44 is not limited to this, and the convex portion 57a is disposed adjacent to the left side (upstream of the optical path) in FIG. It may be a thing. With these arrangement relationships, the flow path through which the airflow flows into the space 61 can be narrowed and the flow path can be bent, so that the airflow flowing into the space 61 can be suppressed.
Further, the convex portion 57a may be provided so as to protrude so as to face the compound lens member 44 (arranged in a direction perpendicular to the optical axis shown in FIG. 3). In such an arrangement relationship, when there is a gap between the convex portion 57a and the compound lens member 44, the gap that narrows the flow path of the airflow flowing into the space 61 and suppresses the airflow flowing into the space 61. Any configuration may be used.

Example 2 will be described below.
FIG. 8 is a schematic perspective view showing the overall configuration of the optical scanning device 3 of this embodiment, and FIG. 9 is a cross-sectional view of the optical scanning device 3 shown in FIG. 8 taken along the optical path of the laser light L2. It is. Since the configurations and functions of the image forming apparatus and the optical scanning apparatus are the same as those described in the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In this embodiment, as shown in FIG. 9, convex portions 57 b and 57 c formed integrally with the lid 57 are provided on the front and rear (upstream and downstream) of the compound lens member 44 on the optical path. Further, the lid 57 is provided with an elastic member 59 such as a flexible urethane foam above the compound lens member 44 and at a position sandwiched between the convex portions 57b and 57c. The convex portions 57 b and 57 c not only separate the space 60 and the space 61 but also hold the elastic member 59.

  In this embodiment, the elastic member 59 is provided so as to close the space between the lid 57 and the compound lens member 44. Thus, when the rotary polygon mirror 45 is driven to rotate, when the air in the space 60 is agitated and an air flow is generated, the air flow as indicated by the arrow F1 indicated by a broken line in FIG. It can be surely suppressed.

As described above, according to the present embodiment, the space 60 in which the rotary polygon mirror 45 serving as the air flow generation source is present and the space 61 in which the slit edge portion 50b is present can be completely separated. Therefore, the sealing degree of the space 61 can be further increased, and dust can be prevented more reliably from flowing into the space 61. Therefore, it is possible to prevent the dust from adhering to the slit edge portion 50b, and consequently to prevent the image quality from being deteriorated due to the dust adhering to the slit edge portion 50b.
Although the number of convex portions has been described as two, the number is not limited and may be appropriately selected depending on the form inside the optical scanning device. Further, the holding of the elastic member 59 is not limited to the form of holding by the convex portion, but may be by adhesion or the like. In this case, the convex portion may not be provided, and the elastic member 59 alone may be used to close the space between the lid 57 and the compound lens member 44. Here, the elastic member 59 and the compound lens member 44 constitute a partition part.
The elastic member 59 may be applied between the convex portion 57a and the composite lens member 44 in the first embodiment.

Example 3 will be described below.
FIG. 10 is a cross-sectional view of the optical scanning device 3 of the present embodiment cut along the optical path of the laser light L2. Since the configurations and functions of the image forming apparatus and the optical scanning apparatus are the same as those described in the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

In the present embodiment, as a partition member that partitions the optical path of the light beam from the lens 44b to the slit edge portion 50b among the light beam deflected and scanned by the rotary polygon mirror 45 and collected by the lens 44b, with the rotary polygon mirror 45. A separation member 62 is provided.
Here, the space 61 in the present embodiment is a space formed by the optical box 50 and the lid 57 and separated by the separating member 62. In the present embodiment, the slit edge 62 a is provided integrally with the separation member 62, not the optical box 50. That is, the separation member 62 has both a space separation function and a slit function. Further, in order for the laser light L2 to pass through the lens 44b and enter the space 61 without being shielded, the separation member 62 is provided with an optical path hole 62b. In the present embodiment, the separating member 62 and the compound lens member 44 are installed in contact with each other, thereby constituting a partition portion.

  According to the present embodiment, the space 60 and the space 61 are separated by the separation member 62. At this time, since the separating member 62 is in contact with the compound lens member 44, only the laser light L2 passes through the optical path hole 62b and enters the space 61, and dust can be prevented from flowing in. Since the slit edge portion 62a is integrated with the separating member 62, dust does not adhere to the slit edge portion 62a unless dust flows into the space 61. Accordingly, it is possible to prevent the dust from adhering to the slit edge 62a, and thus it is possible to prevent the image quality from being deteriorated. Further, since the slit edge portion 62a is integrated with the separation member 62, the slit edge portion 62a is more accurately positioned with respect to the lens 44b by installing the separation member 62 in contact with the compound lens member 44. be able to. As a result, the detection sensor 49 can detect the writing timing more accurately.

  In this embodiment, the case where the separating member 62 and the compound lens member 44 are installed in contact with each other has been described. However, the present invention is not limited to this. The arrangement relationship between the separating member 62 and the composite lens member 44 may be such that there is a gap as in the arrangement relationship between the convex portion 57a and the composite lens member 44 described in the first embodiment. That is, the separation member 62 is preferably disposed without a gap between the wall portion 50f of the optical box 50 in which the detection sensor 49 is disposed and the composite lens member 44. However, the wall portion 50f and the composite lens member are preferably disposed. There may be a gap for each of 44.

Here, a modification of the present embodiment shown in FIG. 10 will be described with reference to FIG.
When the separation member 62 as described above is provided, there is no need to define the gap between the lid 57 and the separation member 62. However, the gap between the lid 57 and the separation member 62 can be narrowed. High dustproof performance can be obtained.
FIG. 11 shows a configuration in which an elastic member 63 such as a flexible urethane foam is provided between the lid 57 and the separating member 62.
In the case of the configuration shown in FIG. 11, by providing the elastic member 63, the gap between the lid 57 and the separation member 62 can be filled (closed). For this reason, since an air current as indicated by an arrow F2 indicated by a broken line in FIG. 11 does not occur, it is possible to prevent the air current from flowing in from the downstream side in the optical path of the laser light L2 of the slit edge portion 62a, and higher dustproof performance Can have. As a result, it is possible to prevent dust from adhering to the slit edge portion 62a, and thus it is possible to prevent deterioration in image quality.

Next, effects unique to the present embodiment will be described.
The optical box 50 is often composed of a highly rigid member such as glass fiber reinforced plastic in order to increase the rigidity. Therefore, if there is a concern that the surface roughness of the slit edge portion is deteriorated by the glass fiber by molding the slit edge portion integrally with the optical box 50, the slit edge portion is separated from the optical box 50. It is good to do. At that time, as in the separation member 62 of the present embodiment, by providing the function as the slit edge portion with a dustproof function, in addition to the same effects as in the first embodiment, an effect that the number of parts can be reduced is obtained. Can do.

Example 4 will be described below.
FIG. 12 is a cross-sectional view of the optical scanning device 3 according to the present embodiment cut along the optical path of the laser light L2. Since the configurations and functions of the image forming apparatus and the optical scanning apparatus are the same as those described in the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

In this embodiment, a convex portion 44c is provided on the composite lens member 44 as a partition portion that partitions the space 60 and the space 61, and the convex portion 44c is fitted into a concave portion 57d provided on the lid 57, and a composite portion. A lens member 44 is provided.
In this seal portion, it is preferable to close the gap between the lid 57 and the compound lens member 44 by fitting the convex portion 44c into the concave portion 57d, but this is not restrictive. That is, the seal portion may constitute a so-called labyrinth seal in which a gap (preferably a minute gap) exists between the convex portion 44c and the concave portion 57d. With such a configuration, the airflow generated by the rotation of the rotary polygon mirror 45 can be narrowed and the flow path can be bent, so that the airflow flowing into the space 61 can be suppressed. be able to.

When the composite lens member 44 is a molded part made of a resin material, it is effective to use the convex portion 44c as a remaining gate portion generated during molding. Further, when the composite lens member 44 is assembled to the optical box 50, high positioning accuracy and ease of assembly are necessary for improving the quality of the entire optical scanning device. Therefore, for example, the convex portion 44c provided on the compound lens member 44 can be used as a projection portion held by an assembly tool.
Thus, according to the present embodiment, by providing the convex portion 44c on the compound lens member 44, in addition to the effect as the partition portion similar to that of the first embodiment, further effects can be obtained.

Here, in this embodiment, the seal portion is configured by forming the concave portion 57d by providing two convex portions 57e on the lid 57, and fitting the convex portion 44c into the concave portion 57d. It is not limited. The seal portion includes a plurality of convex portions 57e and a plurality of convex portions 44c, and is arranged so that one convex portion 57e and one convex portion 44c are alternately adjacent (aligned in the optical axis direction shown in FIG. 12). May be arranged).
Further, the seal portion may be constituted by one convex portion 57e and one convex portion 44c, and disposed so that the convex portion 57e and the convex portion 44c are adjacent to each other. If there is a gap between the convex portion 57e and the convex portion 44c, the gap may be configured so as to suppress the airflow flowing into the space 61 by bending the flow path of the airflow flowing into the space 61. Good.

Further, the convex portion 57e and the convex portion 44c are not limited to the configuration arranged adjacent to each other, but are opposed to each other (for example, arranged side by side in a direction orthogonal to the optical axis shown in FIG. 12). Also good. If there is a gap between the convex portion 57e and the convex portion 44c, it may be configured to have a gap that narrows the flow path of the airflow flowing into the space 61 and suppresses the airflow flowing into the space 61. .
As described above, the convex portion 57e provided on the lid 57 and the convex portion 44c provided on the compound lens member 44 narrow the flow path flowing into the space 61 so that the airflow flowing into the space 61 can be suppressed. It is good if it is configured as follows. Furthermore, the convex part 57e and the convex part 44c are good to be comprised so that the flow path which flows into the space 61 may be bent so that the airflow which flows into the space 61 can be suppressed. Furthermore, in addition to the convex portions 57e and the convex portions 44c, an elastic member such as a flexible urethane foam may be appropriately disposed to constitute the seal portion.
Moreover, the structure by which the convex part 44c is provided only in the composite lens member 44 side among the lid | cover 57 and the composite lens member 44 may be sufficient. That is, at least one of the lid 57 and the compound lens member 44 is a protruding portion that protrudes toward the other side so as to narrow the flow path of the airflow flowing into the space 61 and suppress the airflow flowing into the space 61. What is necessary is just to be provided. Furthermore, an elastic member such as a flexible urethane foam may be appropriately disposed on the projecting portion to block the airflow path flowing into the space 61.

  DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum, 3 ... Optical scanning device, 41 ... Semiconductor laser, 44 ... Compound lens member, 49 ... Detection sensor, 50 ... Optical box, 50b ... Slit edge part, 57 ... Cover, 57a ... Convex part

Claims (7)

A deflection scanning means for deflecting and scanning the light beam emitted from the light source by being driven;
An optical scanning device that forms an image of a light beam deflected and scanned by the deflection scanning unit on a scanned object,
In order to determine the position where the light beam deflected and scanned by the deflection scanning means starts scanning on the scanned object, the light beam is detected by being incident before being imaged on the scanned object. Detecting means for
A regulating unit that regulates the optical path of the light beam so that the light beam deflected and scanned by the deflection scanning unit is incident on the detection unit at a preset position;
An optical box in which the deflection scanning unit, the detection unit, and the regulating unit are disposed;
A lid covering the optical box;
In an optical scanning device comprising:
It is characterized by comprising a partition part for partitioning the space formed by the optical box and the lid in which the deflection scanning means and the restriction part exist, between the deflection scanning means and the restriction part. Optical scanning device.   The optical scanning device according to claim 1, wherein the partition portion includes a condensing member that condenses the light beam deflected and scanned by the deflection scanning unit on the detection unit. The partition is
A support member disposed in the optical box and supporting the light collecting member;
At least one of the support member and the lid is configured to narrow a flow path in which the air flow generated by driving the deflection scanning unit flows into the restriction portion from between the support member and the lid. A protruding portion that is provided and protrudes toward the other side of the support member and the lid;
The optical scanning device according to claim 2, comprising: Each of the one and the other is provided with the protrusion,
4. The projecting portion provided on the one side and the projecting portion provided on the other side are disposed adjacent to each other so as to bend the flow path. The optical scanning device described. The partition is a partition for partitioning an optical path of a light beam from the light collecting member to the regulating portion among the light beams deflected and scanned by the deflection scanning unit and condensed by the light collecting member, with the deflection scanning unit. Including members,
The optical scanning device according to claim 2, wherein the restriction member is provided integrally with the partition member. A support member disposed in the optical box and supporting the light collecting member;
The optical scanning device according to claim 2, wherein the partition portion includes an elastic member that closes a space between the support member and the lid.   The optical scanning device according to claim 5, wherein the partition portion includes an elastic member that closes a space between the partition member and the lid.

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