JPH0745048Y2 - Optical adjustment device for image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an optical adjusting device in an image forming apparatus such as an optical printer.

[Conventional technology and its problems]

Conventionally, in an image forming system such as an optical printer, a short focus lens array is generally used as the image forming element. This short focus lens array has a characteristic that the focal length is short and the depth of focus is very shallow. Therefore, if the position of the short focus lens array deviates from the formed image, the resolution is unavoidably reduced.

In order to eliminate such a defect of the short focus lens array, it is necessary to provide a mechanism for finely adjusting the position of the short focus lens array. As this mechanism, for example, the sixth
As shown in the figure, there is a U-shaped groove 50 provided on both sides of the short focus lens array, and the groove 50 is used to support the shaft 51 such as a shaft or a pin provided in the printer main body. The pivot 51 has a structure that is movable in the direction of coming into contact with and separating from the image forming surface of the photoconductor drum 52, and by moving this,
The position of the short focus lens array can be adjusted.

However, from the viewpoint of assembly, the groove 50 requires a structure that slides with respect to the pivot shaft 51, so that there is a slight gap between the inner surface of these grooves 50 and the outer surface of the pivot shaft 51. The interposition of this gap results in displacement of the short focus lens array, and an appropriate resolving power cannot be obtained. Further, since the groove 50 is constrained by the pivot 51, the force for supporting the own weight of the short focus lens array is rigidly applied to both ends, so that the short focus lens array is deformed.
Therefore, in addition to the positional displacement, the directivity of the short focus lens array becomes poor, which causes a problem that the resolution is adversely affected.

In addition to the structure for correcting the resolving power as described above, there is also a structure for adjusting the position by using a jig as described in JP-A-60-37575. In this method, a short focus lens array whose focus adjustment is delicate is adjusted on a jig, and then the short focus lens array is positioned and fixed by a mechanical means such as a screw.

However, since the fixation by the screw can be performed by the correlation between the screw pitch and the rotation amount, the position adjustment in the extremely small order becomes discontinuous. That is, because of mechanical adjustment by rotating the screw, deviation inevitable in the range of 50 to 100 μm is unavoidable, and when fine adjustment to fall within this range is required, the work is repeated several times. There is a need. Therefore, the adjustment time is long and the adjustment cost is high, and it is difficult to obtain a good resolution.

Further, in an optical printer using a short focus lens array, in order to clean the optical surface of the short focus lens array, as disclosed in, for example, JP-A-60-17731 and JP-A-58-11770. Various cleaning members are provided. However, since the distance between the short focus lens array and the photoconductor is extremely small, it is difficult to dispose the cleaning member between them. On the other hand, since the position of the short focus lens array with respect to the photoconductor must be set strictly in order to obtain the resolving power, this short focus lens array is generally fixed to the printer frame or the like. Therefore,
Since the cleaning of the optical surface is complicated and the cleaning degree cannot be maintained high, the resolution is unfavorably affected.

As described above, in the image forming apparatus including the short focus lens array, it is considerably difficult to position and fix the photosensitive body on the photoconductor, and the photosensitive surface of the short focus lens array cannot be sufficiently cleaned, so that a good resolving power is obtained. There are still problems regarding the points.

Therefore, the present invention improves the resolving power by facilitating the positioning of the short focus lens array arranged in the vicinity of the photoconductor with high precision and by easily cleaning the optical surface of the lens. The purpose is to

[Means for solving problems]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an array guide, which is arranged opposite to the periphery of a photoconductor drum and accommodates a short focus lens array extending in the width direction of the photoconductor drum, and an array guide. A light emitting element array that is arranged adjacent to each other in the optical axis direction and is wider than the array guide that irradiates the short focus lens array with light, and the array guide and the light emitting element array are movably connected to each other along the optical axis. A screw for providing an integrated structure, a first elastic means interposed between the array guide and the light emitting element array and urging the array guide and the light emitting element array away from each other; A positioning block having a space for fitting the array guide, and the array guide being detachably fitted therein; and the light emitting element array in the integrated structure, Characterized by providing a second resilient means for urging, to.

[Action]

In the present invention, an array guide having a short-focus lens array housed therein is movably connected to the light emitting element array by a screw, and the array guide is elastically biased in a direction away from the light emitting element array. ing. Therefore, the distance between the array guide and the light emitting element array is adjusted in a state where a force in one direction is elastically applied to the array guide. For this reason, even if there is play in the screw portion, this play is suppressed by the elastic force, and the play is not affected. In addition, since the array guide is elastically supported with respect to the light emitting element, the array guide and the built-in short focus lens array are not subject to distortion deformation.

In addition, the array guide and the light emitting element array have an integrated structure via a screw, and by fitting this integrated structure into the space formed in the positioning block, the inner peripheral surface of the block and the array are arranged. The outer peripheral surfaces of the guides come into contact with each other, and positioning is accurately performed. Further, since the light emitting element array in the integrated structure is biased toward the photoconductor drum by the second elastic means, the wide portion of the light emitting element array comes into contact with the block and the positioning in the optical axis direction is accurately performed. Done.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.

FIG. 1 is a sectional view schematically showing a main part of an image forming apparatus equipped with an optical adjusting device according to the present invention.

In the figure, a charger 2, a developing device 3, a cleaner 4 and the like are arranged around the photosensitive drum 1 which forms an image of a latent image, as in a normal electrophotographic copying machine. Developer 3
A short-focus lens array 5 is provided between and. The short focus lens array 5 includes a plurality of lenses which are formed on the photosensitive drum 1.
Are arranged in the direction of the axis, and are housed in the array guide 6. The array guide 6 also includes a light emitting diode (LE
D) Built-in light emitting diode array head (hereinafter, LED
An array head) 7 is integrated. These optical system elements are held at fixed positions by a positioning block 8 provided in the image forming apparatus, and are removable from the block 8. In addition to the light emitting diode, a liquid crystal head including a light source and a liquid crystal shutter may be used as the light emitting element.

The attachment / detachment mechanism of the integrated body of the array guide 6 and the LED array head 7 to / from the block 8 is, for example, arranged such that the blocks 8 are arranged in parallel with the axis of the photoconductor drum 1 at intervals as shown in the drawing. A structure that fits can be adopted. Then, in order to make the positioning accurate, an elastic mechanism 9 such as a leaf spring for urging the LED array head 7 toward the photosensitive drum 1 is provided. It should be noted that a handle 10 is preferably provided on the LED array head 7 in order to facilitate the attachment / detachment operation.

As described above, the array guide 6 including the lens array 5 and the LED array head 7 accommodating the light emitting element are integrated and the block 8 to which the LED array head 7 is attachable / detachable is provided, whereby an optical system including the lens array 5 is provided. Can be freely removed. Therefore, the array guide 6 and the LED
If the array head 7 is removed from the block 8, the optical surface of the lens array 5 can be easily cleaned. By keeping the optical surface clean, the resolution can be improved and the parts can be easily replaced.

FIG. 2 is a perspective view of a main part showing an example of an integrated structure of the array guide 6 and the LED array head 7.

As shown in the figure, a flange 11 is integrally provided at the end of the array guide 6, and the array guide 6 is attached to the LED array head 7 by a screw 12 as a screw which is inserted into the flange 11 and screwed into the LED array head 7. They are movably connected to each other at intervals. Further, a leaf spring 13 is interposed between the flange 11 and the LED array head 7 as a mechanical elastic means for urging the LED array head 7 and the LED array head 7 away from each other. In addition,
Instead of this leaf spring 13, a compression coil spring 14 may be used as shown in FIG.

In such a structure in which the array guide 6 and the LED array head 7 are connected and integrated, the screw 12 can be screwed into the LED array head 7 to change the distance between them. Here, as shown in FIG. 1, when fitted into the block 8, a sleeve which is integrated with the LED array head 7 and accommodates the array guide 6 slidably in the direction of the photosensitive drum 1.
With the provision of 15, the distance between the photosensitive drum 1 and the photosensitive drum 1 can be adjusted even when mounted on the block 8.

The position of the array guide 6 is adjusted by changing the distance from the LED array head 7.
Is set to a fixed position with respect to the photoconductor drum 1 by the block 8, and as a result, the position of the array guide 6 with respect to the photoconductor drum 1 can be adjusted. And the leaf spring 13
The elastic support structure that buffers the rigid connection by the screw 12 can be obtained because the elastic support structure is interposed. Therefore, even if there is looseness in the fitting between the screw 12 and the screw hole provided in the LED array head 7, it can be absorbed and the array guide 6 can be held in a static state.

The cushioning function of the leaf spring 13 is used for the array guide 6
It is possible to effectively prevent the displacement of the position of, and it is also possible to finely adjust the position. That is, in the connection structure of only screw 12,
As described above, in addition to the occurrence of backlash due to the fitting error with the screw hole of the LED array head 7, it is quite difficult to adjust the position by the correlation between the screw pitch and the rotation amount. On the other hand, if the elastic force of the leaf spring 13 is utilized, the amount of play, which cannot be compensated for by the rotating operation of the screw 12, can be absorbed and adjusted.

Further, since the leaf spring 13 applies an elastic force to the rigid connection by the screw 12, it is possible to suppress the strain deformation and the like generated at the end portion of the array guide 6. Therefore, the stored lens array 5
It is possible to prevent defective resolution without adversely affecting the image quality.

FIG. 4 is a perspective view showing an example in which a plate glass 16 is arranged between the photosensitive drum 1 and the array guide 6 in addition to the position adjustment using the screw 12 and the plate spring 13 of the array guide 6.
The figure is a schematic sectional view of a main part. The plate glass 16 is used to form the irradiation light from the lens array 5 on the surface of the photoconductor drum 1 with good resolving power by utilizing its refractive index.
This plate glass 16 is formed by superposing a plurality of sheets,
It is possible to make various adjustments to the focal length using the synthetic refractive index.

For example, when the relative position of the array guide 6 and the photosensitive drum 1 is set so that the plate glass 16 is in focus when the plate thickness is 2 mm, the accuracy of this position setting should be 0.3 mm from the viewpoint of mass production of parts. Is enough. On the other hand, if the plate thickness of the plate glass 16 is prepared in the range of 1 to 3 mm at intervals of 0.2 mm, the optical path length will be 0.33 to 1 mm compared with the design value.
It can be set at intervals of 0.067 mm. Therefore, the plate glass 16
By properly selecting the number of sheets, it becomes possible to focus on the surface of the photosensitive drum 1. In this way, plate glass 16
Array guide 6 adjusted by using
It is possible to correct the image forming system due to, and further improve the resolving power.

In the above-described embodiment, the screw 12 is rotated in the direction away from the photosensitive drum 1 to adjust the array guide 6, but the screw 12 is adjusted from the LED array head 7 side to the flange of the array guide 6. By screwing into 11, the position can be adjusted from the direction toward the photosensitive drum 1.

[Effect of device]

As described above, in the optical adjusting device of the image forming apparatus of the present invention, the array guide, which is arranged facing the peripheral surface of the photosensitive drum and accommodates the short focus lens array, is screwed into the light emitting element array with a screw. It is provided with elastic means that are movably connected to each other at a distance and that urges in a direction of expanding the distance. Therefore, since the play due to the screw connection can be absorbed by the elastic means, the position of the array guide with respect to the light emitting element array can be set to be corrected,
The resolution of the image forming system on the photosensitive drum is improved. Further, since the array guide is elastically supported by the elastic means with respect to the rigid connection by the screw, distortion deformation of the array guide and the built-in short focus lens array can be prevented, and the resolving power of the imaging system can be further improved. Can be improved.

Further, in the present invention, the array guide and the light emitting element array are integrated with each other with screws, and this integrated structure is used as a positioning block by utilizing the outer peripheral surface of the array guide and the wide portion of the ignition element array. Since it is detachably attached, the array guide accommodating the lens array can be removed to easily clean the optical surface of the lens array and the parts can be easily replaced.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a main part of an image forming apparatus having an optical adjustment device according to the present invention, and FIG. 2 is a perspective view of a main part showing an integrated structure of an array guide and a light emitting element array, FIG. 3 is a perspective view showing another example of the integrated structure, FIG. 4 is a perspective view showing a correction structure of an image forming system by a plate glass, FIG. 5 is a schematic sectional view of FIG. 4, and FIG. It is an explanatory view showing a support structure of the lens array of. 1: Photoconductor drum, 2: Charger 3: Developer, 4: Cleaner 5: Short focus lens array 6: Array guide 7: Light emitting diode array head 8: Block, 9: Elastic mechanism 10: Handle, 11: Flange 12 : Screw (screw), 13: Leaf spring (elastic means) 14: Compression coil spring (elastic means) 15: Sleeve, 16: Flat glass

Claims (1)

[Scope of utility model registration request] 1. An array guide, which is arranged opposite to the periphery of a photoconductor drum and accommodates a short focus lens array extending in the width direction of the photoconductor drum, and an array guide adjacent to the array guide in the optical axis direction. Placed,
A light emitting element array wider than the array guide for irradiating the short focus lens array with light, and an array structure in which the array guide and the light emitting element array are movably connected to each other along an optical axis. A screw, a first elastic means interposed between the array guide and the light emitting element array and biasing the array guide and the light emitting element array in a separating direction, and for fitting the array guide in the integrated structure. A positioning block having a space into which the array guide is detachably fitted, and a second elastic means for urging the light emitting element array in the integrated structure toward the photoconductor drum are provided. An optical adjustment device for an image forming apparatus, characterized in that.