JP2001130047A - Electrophotographic recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic recording apparatus reducing focal shift generated when the positional shift of a scanning line is corrected. SOLUTION: Since an LED printing head 17 is energized to a photosensitive drum 14 by a coil spring 52, the leading end of a contact rod 40 is always brought into contact with the surface 14A of the photosensitive drum 14. Therefore, even if the contact position of the contact rod 40 is adjusted by a screw 48, the distance between the LED printing head 17 and the surface 14A of the photosensitive drum 14 is not almost changed as compared with that before adjustment over the whole of the LED printing head 17. As a result, the focal shift of a scanning line to the surface 14A is markedly reduced as compared with conventional one.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic recording apparatus, and more particularly, to an electrophotographic recording apparatus using an LED print head.

[0002]

2. Description of the Related Art Electrophotographic recording apparatuses such as copying machines and printers are widely used. This electrophotographic recording apparatus is provided with a print head, and as the print head, an LED print head having an LED array is frequently used. Hereinafter, a conventional electrophotographic recording device (also referred to as an optical writing device) will be described with reference to the accompanying drawings by way of example.

[0003] As shown in FIG. 11, a conventional electrophotographic recording apparatus 120 includes yellow, magenta, sian,
It has four recording units 122A to 122D for recording four colors of black, respectively. The recording unit 122 </ b> A that performs yellow recording includes a rotating photosensitive drum 126, an LED print head 124 (hereinafter, referred to as a head 124) that exposes the surface of the photosensitive drum 126, and a charger 12.
8, the developing device 130, the cleaner 132, and the transfer device 13
4, and the same applies to the other recording units 122B to 122D.

The head 124 includes a light emitting element array which is arranged in series in the main scanning direction and is controlled to blink by an image signal, and an image forming element array which forms a light image of the light emitting element array. discharge.

When the electrophotographic recording apparatus 120 is assembled, for example, a relative displacement between the photosensitive drum 126 and the head 124 occurs. Therefore, as shown in FIG. 12, the scanning line for scanning the surface of the photosensitive drum 126 is not L0 parallel to the rotation axis C3 of the photosensitive drum 126, but is slightly inclined with respect to the rotation axis C3, that is, the skew. Scanning lines L1 and L2. The skew amount, that is, the deviation in the sub-scanning direction at both ends of the scanning line is about 0.5 to 1.0 mm depending on the tolerance of the components. Hereinafter, in the present specification, the inclination of the scanning line in the sub-scanning direction with respect to the rotation axis of the photosensitive drum is referred to as the inclination of the scanning line.

A countermeasure for correcting the inclination of the scanning line is disclosed in Japanese Patent Application Laid-Open No. 08-181871. JP 08-181871
In the publication, an electrophotographic recording device 14 as shown in FIG.
0 is disclosed. The electrophotographic recording apparatus 140 includes a generation unit that generates color separation information for forming a color image, and a conveyance unit that conveys a recording medium. Each color image is sequentially superimposed and recorded on a medium (for example, paper).

Further, the electrophotographic recording apparatus 140 includes a color misregistration detecting means for detecting an amount of color misregistration generated on the recording medium,
D print head 142 (hereinafter referred to as head 142)
And correction means for correcting the relative color shift amount of each color separation information, that is, the inclination of the scanning line, for each color. The electrophotographic recording apparatus 140 corrects the inclination of the scanning line for each color based on the sense signals obtained from the color misregistration detection unit and the conveyance unit.

The correcting means includes an adjusting mechanism 150 for adjusting a twist angle between the rotation axis of the photosensitive drum 144 and the main scanning direction of the scanning light. The adjusting mechanism 150 includes the head 14
2 is provided at the other end with a support pin 156 for rotatably supporting one end in the main scanning direction in the sub-scanning direction. At one end of the head 142, a slide block 154 is provided. The slide block 154 has a screw 1
The slide block 154 can be slid in the sub-scanning direction by rotating the screw 152 to advance and retreat.

By the way, a selfoc lens is usually used for the coupling element array. As shown in FIG. 14, the amount of defocus determined by the distance between the focal point 148 of the Selfoc lens 146 and the surface 144A of the photosensitive drum 144 (hereinafter, this distance is referred to as the amount of defocus). Is affected by the opening angle of the Selfoc lens 146, but the allowable range is very small.

Therefore, in the electrophotographic recording apparatus 140 disclosed in Japanese Patent Application Laid-Open No. 08-181871, the photosensitive drum 144
Is reduced, the position of the photosensitive drum 144 and the head 1
Since the distance from the imaging element array 42 greatly changes, a problem arises in that image quality deteriorates due to defocus, that is, defocus. This problem is not a problem when the photosensitive drum is relatively large.
This problem is expected to become more serious in the future.

The fact that a large defocus occurs when a photosensitive drum having a small diameter is used will be described below using a specific example. As shown in FIG. 14, in the case where a photosensitive drum 144 having a diameter D of 30 mmφ is used, the inclination of the scanning line is corrected in the sub-scanning direction (the direction of paper feed).
V to rotate the head 142 so that the selfoc lens 1
When 46 is moved by d = 1 mm as shown by a two-dot chain line, the maximum defocus amount Ymax between the surface of the photosensitive drum 144 and the coupling element array becomes about 35 μm. This maximum defocus amount is out of an allowable range. As the diameter of the photosensitive drum 144 further decreases, Ymax further increases.

Further, the electrophotographic recording apparatus 1 shown in FIG.
In 20, not only the misalignment in the sub-scanning direction but also the main scanning direction mainly due to the magnification difference due to the mounting error between the light emitting element array in each print head and the coupling element array for forming the light image of the light emitting element array. It is also a problem that displacement (color misregistration) occurs up to several tens of μm. The problem of color misregistration due to the magnification difference is a problem even if the photosensitive drum is relatively large.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic recording apparatus in which the amount of defocus generated when a positional deviation of a scanning line is corrected is small in consideration of the above fact.

[0014]

According to the first aspect of the present invention, a photoconductor drum and an LED provided along a rotation axis of the photoconductor drum and provided with LEDs arranged in a main scanning direction are provided.
An electrophotographic recording apparatus comprising: an ED print head; and an adjustment unit configured to move the LED print head in a sub-scanning direction with respect to the photosensitive drum. Urging means for urging toward the LED print head, and abutting against the surface of the photoconductor drum, the urging means;
And two stoppers for defining a distance between the ED and the photosensitive drum.

Since the LED print head is urged toward the photosensitive drum by the urging means, the tip of the stopper always comes into contact with the surface of the photosensitive drum. Therefore, even if the adjustment is made by the adjusting means, the distance between the LED print head and the surface of the photosensitive drum hardly changes over the entire LED print head as compared with before the adjustment. Therefore, the amount of defocus is remarkably small as compared with the related art.

According to a second aspect of the present invention, the adjusting means rotates the LED print head in the sub-scanning direction about one of the stoppers as a rotation axis.

According to a third aspect of the present invention, the adjusting means is configured such that the center of the two stoppers is a rotation axis and the LE is
A rotating means for rotating the D print head in the sub-scanning direction is provided.

This makes it possible to reduce the moving distance of the end portion and to reduce the maximum defocus amount as compared with the case where one of the stoppers is used as a rotation axis.

According to a fourth aspect of the present invention, the adjusting means may be configured such that the center of the two stoppers is a rotation axis.
A swing means for rotating the D print head in the sub-scanning direction and tilting the LED print head with respect to the photosensitive drum is provided. As a result, the amount of defocus can be further reduced.

According to a fifth aspect of the present invention, the contact portion of the stopper that contacts the photosensitive drum is formed in a curved surface having the same curvature as the photosensitive drum. The curved shape is usually a hemispherical shape, but may be a cylindrical side surface.

[0021] Thus, the variation in the distance between the LED print head and the photosensitive drum can be minimized at any position, so that the maximum defocus amount can be reduced.

According to a sixth aspect of the present invention, the swing means is connected to the support member at one end to support the LED print head so as to swing in the sub-scanning direction. A rotation member having a rotation center at a position separated by the same distance as the diameter of the photosensitive drum.

Thus, since the head surface of the LED print head faces the surface of the photosensitive drum, the maximum defocus amount can be further reduced.

According to a seventh aspect of the present invention, there is provided the light emitting device according to the first aspect, wherein the LED is controlled in accordance with an inclination of a scanning line with respect to a rotation axis of the photosensitive drum.
A light emission timing changing means for changing the light emission timing for each LED.

Thus, when the degree of inclination of the scanning line (hereinafter referred to as the amount of inclination of the scanning line) is increased to perform magnification correction in the scanning direction, the amount of inclination of the scanning line is detected by an electric signal or the like. By adjusting the light emission timing of the LED according to this amount, correction in both the main scanning direction and the sub-scanning direction becomes possible.

[0026]

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the electrophotographic printing apparatus 10 of the first embodiment has four printing units 12A to 12D for printing four colors of yellow, magenta, sian, and black, respectively. The recording unit 12A that performs yellow recording includes a cylindrical photosensitive drum 14.
And a charger 16 for charging the surface 14A of the photoconductor drum 14, and an LE for exposing the surface 14A of the photoconductor drum 14
D print head 17, developing device 20, transfer device 22
And a cleaner 24.

As shown in FIG. 2, the LED print head 17 (hereinafter simply referred to as the print head 17) is provided along the rotation axis C3 of the photosensitive drum 14, and incorporates LEDs arranged in a line. It comprises a head section 15 and a holder section 18 provided on the lower surface side of the head section 15 for holding a selfoc lens and determining a distance between the selfoc lens and the LED. Inside the head section 15,
A light emitting element array controlled to be turned on and off by an image signal, and an image forming element array for forming an optical image of the light emitting element array are arranged in series in the main scanning direction U in the holder section 18. A scan line is emitted toward.

The electrophotographic recording apparatus 10 (see FIG. 1)
Has a position adjusting device 30 for adjusting the relative position of the head unit 15 with respect to the photosensitive drum 14. The position adjusting device 30 projects from the one end of the head portion 15 by a predetermined length,
A contact rod 32 is provided which comes into contact with the front surface 14A of the photosensitive drum 14 at the tip. The contact rod 32 penetrates the support member 34 and supports the head portion 15 so as to be rotatable around the axis of the contact rod 32.

At the other end of the head 15, a contact rod 40, which comes into contact with the surface 14 A of the photoreceptor drum 14, has the same length as the contact rod 32. The contact rod 40
From both sides in the sub-scanning direction, the tip of a spring 44 fixed to the frame 42 and the tip of an adjusting screw 48 screwed into and penetrating the plate 46 are in contact with each other. When the adjusting screw 48 is advanced or retracted in the same direction as the biasing direction of the spring 44 or in the opposite direction, the contact rod 40 moves, and the head 15 rotates in the sub-scanning direction with the tip of the contact rod 32 as a rotation fulcrum. It is a configuration to do.

The tips of the contact rods 32 and 40 are shaped so as to smoothly move on the surface 14A of the photosensitive drum 14, and are, for example, conical and rounded at the apex.

On the other hand, a receiving plate 50 is provided above the head 15.
The coil spring 52 is attached to the receiving plate 50 to urge the head portion 15 downward. Thus, the tips of the contact rods 32 and 40 always contact the surface 14A of the photosensitive drum 14, and the distance between the head 15 and the surface 14A is kept constant.

When the position of the head section 15 is adjusted by the position adjusting device 30, for example, when the screw 48 is advanced, the contact rod 40 moves to the left (see FIG. 2B) and the photosensitive drum 14 Move along the surface. This allows
Selfoc lens of the holder unit 18 and the photosensitive drum 14
Can be kept constant with the surface 14A. Therefore, the amount of defocus is much smaller than that of the electrophotographic recording apparatus 140 disclosed in Japanese Patent Application Laid-Open No. 08-181871.

Although the recording unit 12A for performing the yellow recording has been described in detail, the other recording units 12B to 12D for performing the magenta, cyan, and black recording respectively have the same configuration and the same configuration. Perform the action. Further, the number and mounting position of the coil springs 52 may be changed according to the size, shape, and the like of the main body 15.

Hereinafter, as shown in FIG. 3, an example in which the diameter of the photosensitive drum is D = 30 mmφ and the end of the LED print head is moved by d = 1 mm will be described. The defocus amount by the recording device 10 and the defocus amount by the conventional electrophotographic recording device 140 will be described in comparison.

In the electrophotographic recording apparatus 10, as shown in FIG.
Moves rightward and downward along the surface 14A of the photosensitive drum 14. For this reason, the scanning lines from the LEDs arranged at the end portions (solid line and broken line) of the head portion 15 are irradiated on the point B on the surface 14A, and no defocus occurs, but the center of the head portion 15 (one point) The scanning lines from the LEDs arranged in (dashed lines) are irradiated on point C, and the maximum defocus occurs due to the head unit 18 and the surface 14A of the photosensitive drum 14 getting too close. This maximum defocus amount is Y2max = 8 μm.

On the other hand, in the electrophotographic recording apparatus 140 (see FIG. 13), after the movement (after the correction), the maximum defocus occurs at the end of the LED print head 142 as shown in FIG. The defocus amount is Y1max = 35 μm generated at point B on the surface 144A. Therefore, in the electrophotographic recording apparatus 10, the maximum defocus amount is greatly reduced.

Hereinafter, the second embodiment will be described. In the description of the second embodiment, the same components as those described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 4, the electrophotographic recording device 58 according to the second embodiment includes an LED print head 60 (hereinafter, referred to as a print head 60) similar to the print head 18 described in the first embodiment. . Print head 6
Reference numeral 0 denotes a head unit 66 provided along the rotation axis of the photosensitive drum 14 and incorporating LEDs arranged in a line.
And a holder portion 64 provided on the lower surface side of the head portion 66 for holding the SELFOC lens and determining the distance between the SELFOC lens and the LED. Is provided with a rotating shaft 62. The rotating shaft 62 is supported by the receiving plate 50.
As a result, the print head 60 can rotate around the rotation shaft 62.

The electrophotographic recording device 58 has a position adjusting device 68 for adjusting the relative position of the print head 60 with respect to the photosensitive drum 14. Position adjustment device 68
The contact rod 72A protrudes from an end of the main body 66 by a predetermined length and abuts on the surface 14A of the photosensitive drum 14 at the tip.
(See FIG. 5A). This contact rod 72A
Are supported by a spring 70 attached to a frame 71 so as to be rotatable about a rotation shaft 62 in the sub-scanning direction.

From the other end of the head section 66, a contact rod 72B which is in contact with the surface 14A of the photosensitive drum 14 is provided so as to project the same length as the contact rod 72A. Contact rod 72B
As shown in FIG. 5B, the distal end of the spring 44 and the distal end of the adjusting screw 48 are in contact with each other from both sides in the sub-scanning direction, as in the first embodiment. When the adjusting screw 48 is advanced or retracted in the same direction as the biasing direction of the spring 44 or in the opposite direction, the contact rod 72 </ b> A moves, and the print head 60 rotates about the rotation shaft 62.

The tips of the contact rods 72A and 72B are formed in a spherical shape or a cylindrical shape having the same radius as the radius R of the photosensitive drum 14 (see FIG. 7). Since the variation in the distance between the head 60 and the photosensitive drum 14 can be minimized, the maximum defocus amount can be reduced. This principle will be described below.

As shown in FIG. 6, if the tips of the contact rods 72A and 72B are supposed to be conical, near the contact rod 72B,
The distance between the head 66 (solid line) and the surface 14A is determined by the contact rod 7
Since the distance is regulated by 2B, defocus hardly occurs. Similarly, near the contact rod 72A, almost no defocus occurs. However, at the center position of the photosensitive drum 14, the height position of the head portion 66 (dashed line) is already at the same height position as the head portion 66 indicated by the solid line or the broken line, and the head portion 66 is located on the surface 14A. Too close to Accordingly, the maximum defocus Y′max occurs at the center of the head section 66.

For example, if the diameter of the photosensitive drum 14 is D = 30
mmφ, and the distance between both ends of the head section 66 is d = 2.5.
mm, the maximum defocus amount is Y′max = 52.2 μm as shown in Table 1.

[0044]

[Table 1]

As shown in Table 1, d = 2.0 m
In the case of m, Y′max = 33.4 μm and d = 1.5
mm, Y′max = 18.8 μm, d = 1.
In the case of 0 mm, Y′max = 8.3 μm and d = 0.
In the case of 5 mm, Y′max = 2.1 μm.

On the other hand, when the tips of the contact rods 72A and 72B are hemispherical, as shown in FIG. 7, when the end of the main body 66 is moved, the spherical portion contacts the surface 14A of the photosensitive drum 14. Since they are in contact with each other, a gap X is formed between the tip of each contact rod 72A, B and the surface 14A. The value of the gap X and the value of the maximum defocus amount are determined by the radius of the photosensitive drum 14, the radius of the tip of the contact rods 72A and 72B, and the movement amount d of the end of the main body 66. For example, the photosensitive drum 14
Is D = 30 mmφ and the distance between both ends of the main body 66 is d = 2.5 mm, the maximum defocus amount Ymax = 26.1 μm as shown in Table 1. Also, d =
In the case of 2.0 mm, Ymax = 16.7 μm and d =
In the case of 1.5 mm, Ymax = 9.4 μm and d =
In the case of 1.0 mm, Ymax = 4.1 μm and d =
When it is 0.5 mm, Ymax = 1.1 μm.
Therefore, in any case, the maximum defocus amount is smaller than the case where the tip of the contact rod 72 is conical.

For easy understanding, the second embodiment has been described on the assumption that both ends of the area irradiated with the scanning lines on the surface 14A and the tips of the contact rods 72A and 72B are located at the same position. However, when this position is different, the tip shape of the contact rods 72A, B may be spherical or cylindrical with a corresponding radius.

The electrophotographic recording apparatus 5 according to the second embodiment
8, as shown in FIGS. 8A and 8B, the contact rod 7
8 may be provided with a photosensitive drum 76 in which abutment rings 74 for positioning the front end are fitted at both ends. Even in this case, the tip of the contact rod 78 may have a spherical shape or a cylindrical side surface with a radius corresponding to the outer diameter of the contact ring 74.

Hereinafter, the third embodiment will be described. In the third embodiment, the same parts as those described in the first embodiment and the second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 9, in an electrophotographic recording apparatus 80 according to the third embodiment, an LED print head 82 (hereinafter, referred to as a print head 82) similar to the first and second embodiments.
It has. The print head 82 includes the photosensitive drum 1
4 and is provided along the rotation axis 4 and includes a head portion 83 and a holder portion 81. The head portion 83 is provided with a pin 84 extending from one end thereof in parallel with the photosensitive drum 14. Further, the rotating shaft 62 supported by the receiving plate 50 is provided in the head portion 83 at a substantially central position in the main scanning direction as in the second embodiment.

Further, the electrophotographic recording device 80 includes a position adjusting device 86 for adjusting the position of the print head 82. The position adjusting device 86 includes an L-shaped member 90 that is turned on the principle of leverage and transmits turning power to the main body 83. At the upper end of the L-shaped member 90, a through hole 88 for penetrating and engaging the pin 84 is formed. The L-shaped member 90 is rotatably supported by a pin 98 at a position where the distance from the through hole 88 is substantially equal to the diameter of the photosensitive drum 14. As a specific example, the photosensitive drum 14
Is D = 30 mmφ, the pin 98 is pivotally supported at a position L = 30 mm below the through hole 88. The L-shaped member 90 is connected to the adjusting screw 9 at the other end.
4 and a spring 96 rotatably supported.

The other end of the head portion 83 is provided with the contact rod 72A and the spring 70 described in the second embodiment.

On the other hand, above the head portion 83, the receiving plate 5
A coil spring 85 is attached to the receiving plate 50 to urge the head portion 83 downward. As a result, the tip of the contact rod 72A is moved to the surface 1 of the photosensitive drum.
Always contact 4A.

At the time of adjustment by the position adjusting device 86, when the adjusting screw 94 is moved forward and backward to rotate the L-shaped member 90, the print head 82 is rotated in the sub-scanning direction and toward the photosensitive drum 14. It becomes possible to tilt, that is, rock. As a result, the head surface of the head portion 81 faces the surface 14A of the photosensitive drum 14, so that
The maximum defocus amount can be reduced.

In the third embodiment, the position of the through hole 88 is set to a position close to the irradiation end of the scanning line for easy understanding.
What is necessary is just to provide the rotation center of the character-shaped member 90 in the position according to it. For example, when the writing width (meaning the scanning distance of one scanning line) is 300 mm, the rotation axis 62 of the print head 82 is set as the center of the writing width, and L
When the distance to the letter-shaped member 90 is 200 mm, the distance from the rotating shaft 62 to the end of the writing width is 150 mm.
× 200/150 = 40 mm may be provided at the lower position.

Hereinafter, the fourth embodiment will be described. The electrophotographic recording apparatus according to the fourth embodiment is different from the electrophotographic recording apparatus 58 according to the second embodiment in that it has a light emission timing changing unit that adjusts the light emission timing of each LED according to the inclination of the scanning line. It is. Hereinafter, components described in the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the fourth embodiment, as shown in FIG. 10A, an LED print head of one recording unit (for example, a recording unit for recording in yellow) and another recording unit (for example, recording in magenta) Recording unit)
Due to the magnification difference with the LED print head, the difference between the position in the paper feed direction of the right end 100A of the yellow recording area 100 and the right end 102A of the magenta recording area 102 is
The case where e = 20 μm occurs on the paper will be described as an example, and correction by the light emission timing changing unit will be described.

First, in the recording unit for recording in the magenta color, the relative position of the LED print head with respect to the photosensitive drum is adjusted by the advance and retreat of the screw 48 to increase the amount of inclination of the scanning line, thereby increasing the magenta recording area. Right end of 102
02A is located at the right end 100 of the yellow recording area 100.
Match A.

In this state, it is assumed that magenta LED
Are simultaneously emitted, the recording area becomes an area indicated by a broken line 104 as shown in FIG. Therefore, when writing from the LED print head to the surface of the photosensitive drum with scanning lines, the light emission timing changing means
A measure is taken to set the light emission timing of each LED according to the moving speed of the surface of the photosensitive drum. That is,
In the recording unit that performs magenta recording, the trace of the scanning line scanned on the surface of the photosensitive drum is parallel to the trace of the scanning line that is scanned on the surface of the photosensitive drum by the recording unit that performs yellow recording. Next, the LEDs are sequentially emitted with a time delay in the arrangement direction. As a result, the magenta recording area 102 is parallel to the yellow recording area 100 as shown by the solid line in FIG.
The above e can be made approximately 0 μm. That is, magnification correction can be performed in both the sub-scanning direction and the main scanning direction by performing magnification correction with the amount of defocus reduced.

Hereinafter, the light emission timing changing means is further provided with a second
The effectiveness of the electrophotographic recording apparatus provided with the adjusting means described in the embodiment will be described in more detail.

For example, the radius of the photosensitive drum 14 and
The radius of the tip of each of the contact rods 72A, B is 42.5 mmφ.
(Diameter 85 mmφ), magnification difference of each head (that is, FIG. 1
E) of 0 (b) is about 20 μm, and the interval between both ends in the sub-scanning direction of the dashed area 104 is b = 3.5 mm. If the timing of light emission of the LED is adjusted to have a time delay as described above in the conventional electrophotographic recording apparatus 140, the maximum defocus amount is 36 μm. On the other hand, when the light emission timing changing means is used in the electrophotographic recording apparatus according to the fourth embodiment, the maximum defocus amount is 18 μm.

[0062]

According to the present invention, the following effects can be obtained.

According to the first aspect of the present invention, the amount of defocus is significantly reduced as compared with the prior art. In addition, since the inclination of the scanning line can be corrected in a state where the amount of defocus is small, the number of scanning lines for which the inclination is corrected can be increased, and the tolerance of the inclination of the photoconductor is increased compared to the related art. Can be eased.

According to the second or third aspect of the present invention, the moving distance of the end portion is shorter and the maximum defocus amount can be reduced as compared with the case where one of the stoppers is used as a rotation axis. Become.

According to the fourth aspect of the invention, the amount of defocus can be further reduced.

According to the fifth aspect of the present invention, the variation in the distance between the LED print head and the photosensitive drum is controlled by
Since the position can be minimized at any position of the LED print head, the maximum defocus amount can be reduced.

According to the sixth aspect of the present invention, since the head surface of the LED print head faces the surface of the photosensitive drum, the maximum defocus amount can be further reduced.

According to the seventh aspect of the invention, it is possible to perform correction in both the main scanning direction and the sub-scanning direction.

[Brief description of the drawings]

FIG. 1 is a partial front view illustrating a configuration of an electrophotographic recording apparatus according to a first embodiment.

FIGS. 2A and 2B are a perspective view and a side view taken along a line II, respectively, showing a photosensitive drum and an LED print head of the electrophotographic recording apparatus according to the first embodiment.

FIGS. 3A and 3B show a first position of the LED print head after correction (after movement), respectively.
3A and 3B are a side view of the photosensitive drum of the embodiment and a side view of a conventional electrophotographic recording apparatus, wherein a solid line indicates a moved end, a broken line indicates the other end, and a dashed line indicates a center position of the LED print head.

FIG. 4 is a perspective view showing a photosensitive drum and an LED print head of an electrophotographic recording apparatus according to a second embodiment.

5 (a) and 5 (b) are side views as seen from arrows IIa-IIa and IIb-IIb in FIG. 4, respectively.

FIG. 6 is a side view showing a tip end position of a virtual contact rod in a second embodiment.

FIG. 7 is a side view showing a tip end position of a contact rod in a second embodiment.

FIGS. 8A and 8B are a partial perspective view and a side view showing a modification of the electrophotographic recording apparatus of the second embodiment, respectively.

FIG. 9 is a perspective view showing a photosensitive drum and an LED print head of an electrophotographic recording apparatus according to a third embodiment.

FIGS. 10A and 10B show an electrophotographic recording apparatus according to a fourth embodiment, respectively, showing a recording area recorded on a sheet before correction in the main scanning direction and after correction. FIG.

FIG. 11 is a partial front view showing a configuration of a conventional electrophotographic recording apparatus.

FIG. 12 is a plan view showing positions of scanning lines on a photosensitive drum by a conventional electrophotographic recording apparatus.

FIG. 13 is a configuration diagram of a conventional electrophotographic recording apparatus disclosed in Japanese Patent Application Laid-Open No. 08-181871.

FIG. 14 is a side view showing a defocus generated in a conventional electrophotographic recording apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Electrophotographic recording device 14 Photoreceptor drum 15 Head part 17 LED print head 18 Holder part 30 Position adjustment device (adjustment means) 32, 40 Contact rod 44 Spring 48 Adjustment screw 52 Coil spring 58 Electrophotography recording device 60 LED print head 62 Rotating shaft 64 Holder part 66 Head part 68 Position adjustment device 70 Spring 72A, B Contact rod (stopper) 80 Electrophotographic recording device 81 Holder part 82 LED print head 83 Head part 84 Pin (support member) 85 Coil spring 86 Position adjustment Device 88 Through-hole (connecting portion) 90 L-shaped member (rotating member) 98 Pin 120 Electrophotographic recording device 126 Photoconductor drum 124 LED printhead 140 Electrophotographic recording device 142 LED printhead 144 Photoconductor drum 150 Adjuster (Adjusting means)

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Takeshi Ken Kato 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd. In-house (72) Inventor Kiyoshi Aikawa 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. 2C162 AE28 AE55 FA17 FA54 FA59 2H071 BA03 BA14 BA16 BA19 BA27 BA29 BA36 DA03 DA15 2H076 AB16 AB42 AB60 AB68 CA03 CA17 DA41

Claims (7)

[Claims] 1. A photosensitive drum, and LEDs provided along a rotation axis of the photosensitive drum and arranged in a main scanning direction.
An electrophotographic recording apparatus comprising: an LED print head comprising: an LED print head; and an adjustment unit configured to move the LED print head in the sub-scanning direction with respect to the photosensitive drum. Urging means for urging toward the photoconductor drum; two stoppers provided on the LED print head, which contact the surface of the photoconductor drum and define a distance between the LED and the photoconductor drum; An electrophotographic recording device, comprising: 2. The electrophotographic recording apparatus according to claim 1, wherein the adjustment unit rotates the LED print head in a sub-scanning direction about one of the stoppers as a rotation axis. 3. The apparatus according to claim 1, wherein the adjusting means includes a rotating means for rotating the LED print head in a sub-scanning direction about a center of the two stoppers as a rotating axis. An electrophotographic recording device as described in the above. 4. The adjustment means rotates the LED print head in the sub-scanning direction about a center of the two stoppers as a rotation axis, and tilts the LED print head with respect to the photosensitive drum. The electrophotographic recording apparatus according to claim 1, further comprising a swinging unit that causes the swinging unit to swing. 5. The photoconductor drum according to claim 1, wherein a contact portion of the stopper that contacts the photoconductor drum is formed in a curved surface having the same curvature as the photoconductor drum. An electrophotographic recording device according to claim 1. 6. A supporting member for supporting the LED print head so as to be capable of swinging in the sub-scanning direction, the swinging means being connected to the supporting member at one end, and having a diameter of the photosensitive drum from a connecting portion. The electrophotographic recording apparatus according to claim 4, further comprising: a rotation member having a rotation center at a position separated by the same distance. 7. A light emission timing changing means for changing the light emission timing of each LED according to the inclination of a scanning line with respect to the rotation axis of the photosensitive drum. The electrophotographic recording apparatus according to claim 6.