JP2008090209A - Focal position adjusting method for exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a focal position adjusting method for an exposure apparatus that reduces unevenness in density of an imaging apparatus occurring due to variation in focal position in LED head. <P>SOLUTION: A regression line P is derived from MTF data S in which focal position for each LED array is obtained and correction of MTF data S<SB>1</SB>and the regression line P are carried out so that slope and segment of the regression line P is "0" (after correction; MTF data S<SB>2</SB>and a regression line Q). Then, distance OS segment with the regression line Q is calculated by calculating a central value (M) for the MTF data S<SB>2</SB>after correction, distance H<SB>1</SB>and H<SB>2</SB>from a bottom surface of a substrate supporting part to a tip of an adjusting pin from the bottom face of the substrate holder of the LED head is calculated and the position of the tip of the adjusting pin is adjusted. Thus, no great unevenness in density occurs in an image forming apparatus. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention particularly relates to a method for adjusting a focal position of an exposure apparatus including a light emitting element array and an imaging element lens array.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, an electrostatic latent image is formed by exposing a photosensitive member according to an image by an exposure device, and the electrostatic latent image is developed on the photosensitive member by toner development. An image is formed by transferring the toner image formed on the toner image to a transfer medium.

  As a light source for forming an electrostatic latent image on a photoconductor, an LD (Laser Diode) has been used in the past. In recent years, a light emitting element such as an LED (Light Emitting Diode) element is associated with each pixel. An exposure apparatus including a light emitting element array arranged in a row and an image forming element lens array in which an image forming lens such as a SELFOC lens is formed so as to image light output from each light emitting element on the surface of the photosensitive member is used. ing.

  In the image forming apparatus using such an exposure apparatus, each LED element of the light emitting element array is driven based on the image data, the light based on the image data is output, and the light output by the imaging lens is transmitted to the surface of the photoreceptor. In this way, the photosensitive member is exposed based on the image data, and the photosensitive member and the exposure device are moved relative to each other (this moving direction is referred to as “sub-scanning direction”), thereby moving the exposure position. An image is formed on the photoreceptor.

However, in an image apparatus equipped with such an exposure apparatus, performance variations among LED elements equipped with a plurality of light emitting elements, variations in each light emitting element, variations in the refractive index distribution of the imaging element lens array, lens arrangement disorder, Density unevenness is likely to occur due to assembly errors between the light emitting element array and the imaging element lens array, variations in the focus position of the LED elements and the amount of emitted light. This density unevenness causes a reduction in image quality.
For this reason, Patent Document 1 discloses a method in which, after printing at the focal position, the LED head is moved in parallel, printing is performed again, the amount of deviation from the photoconductor is calculated from the pattern, and the focus is adjusted. Therefore, it is necessary to shift the position of the LED head to print out a plurality of sheets, which takes time and productivity is poor.

  Further, Patent Document 2 discloses a method of adjusting the focal position by means of elastically deforming the LED substrate or the lens. However, since the lens can be deformed only in one direction, alignment with high robustness as a whole is possible. It is difficult to do.

Further, Patent Document 3 discloses a method for positioning an LED head by selecting positioning members having different lengths, but many positioning members are required, and the configuration of the LED head becomes complicated. In addition, it is difficult to accurately adjust the focal position due to variations in positioning members.
In Patent Document 4, an eccentric cam is brought into contact with an optical print head (corresponding to an LED head), and the focal position of the optical print head is adjusted by rotating the shaft of the eccentric cam. A separate mechanism is required, and the size of the optical print head increases.
JP-A-62-166372 JP-A-9-1857 JP 2003-11414 A JP 2003-285471 A

  SUMMARY OF THE INVENTION In consideration of the above facts, an object of the present invention is to provide a method for adjusting the focal position of an exposure apparatus that can reduce density unevenness in an image apparatus caused by variation in the focal position of an LED head.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a focus position adjusting method for an exposure apparatus, comprising: a substrate on which a plurality of light emitting elements are arranged in a line; and light emitted by the light emitting elements. An imaging element that forms an image on an object to be exposed, a support member that supports at least one of the substrate and the imaging element, and a focal position adjustment that moves the support member in a direction in which the object is in contact with or separated from the object to be exposed A regression line is obtained from the focal position data on the coordinates where the focal position of each light emitting element is obtained, and when the slope of the regression line is set to 0, the focal position of the light emitting element on the regression line is The position of the support member is adjusted by the focal position adjusting means so as to be the surface of the object to be exposed.

  According to the first aspect of the present invention, at least one of the substrate on which the plurality of light emitting elements are arranged in a line and the imaging element that forms an image of the light emitted from the light emitting elements on the object to be exposed is provided by the support member. Supported. Then, the focal position of the light emitting element is adjusted by the focal position adjusting means for moving the imaging element in the direction in which the imaging element is moved toward and away from the object to be exposed.

  Since the focal positions of a plurality of light emitting elements arranged vary, a regression line is obtained from the focal position data on the coordinates where the focal positions of the respective light emitting elements are obtained, and the regression line is obtained when the slope of the regression line is zero. The position of the imaging element is adjusted by the focal position adjusting means so that the focal position of the light emitting element located above becomes the surface of the object to be exposed. As a result, the focal position of the light emitting element becomes the surface of the object to be exposed, and density unevenness of the image device caused by variation in the focal position of the light emitting element can be reduced.

  Here, the focus position adjusting means is formed on the support member, and the support member itself is provided with an adjustment function for adjusting the position of the support member, so that it is not necessary to provide a complicated position adjustment device on the support member. It won't grow.

  According to a second aspect of the present invention, in the focal position adjustment method of the exposure apparatus according to the first aspect, the focal position data is determined from the maximum value and the minimum value of the focal position data when the slope of the regression line is set to zero. Is calculated, and the adjustment amount of the support member is corrected from the amount of deviation between the median value and the regression line.

  Since the regression line itself may not be at the center of the variation in the focal position data, the positional adjustment of the support member based on the regression line obtained in claim 1 may cause the focal position shift amount of the light emitting element to increase. is there. For this reason, in the invention described in claim 2, large density unevenness is caused in the image device by adjusting the position of the support member by adding or dividing the deviation amount between the median value of the focal position data and the regression line. It can be prevented from occurring.

  According to a third aspect of the present invention, in the method for adjusting the focal position of the exposure apparatus according to the first or second aspect, the focal position adjusting unit moves the imaging element in or away from the object to be exposed. Along the first screw hole formed in the support member and the first screw hole so as to be able to be screwed into, and the tip end portion comes into contact with the main body side frame that supports the object to be exposed. An adjustment pin that contacts and separates the support member, a second screw hole that is formed in a direction orthogonal to the first screw hole, is connected to the first screw hole, and is screwed into the second screw hole. And a fixing screw for fixing the adjustment pin by pressing the pin.

  According to a third aspect of the present invention, a first screw hole is formed in the support member along a direction in which the imaging element is brought into contact with and separated from the object to be exposed, and an adjustment pin can be screwed into the first screw hole. Yes. The tip of the adjustment pin comes into contact with the main body side frame that supports the object to be exposed, and the support member is brought into contact with and separated from the object to be exposed by being screwed into the first screw hole. Further, the support member is formed with a second screw hole connected to the first screw hole in a direction orthogonal to the first screw hole, and the fixing screw is screwed into the second screw hole so that the side surface of the adjustment pin is The adjustment pin is fixed by pressing.

  As described above, since the position of the light emitting element can be adjusted by the screwing amount of the adjustment pin, the adjustment is easy. Further, since no complicated mechanism is used, the cost is low.

  According to a fourth aspect of the present invention, in the method for adjusting a focal position of an exposure apparatus according to any one of the first to third aspects, the focal position is a modulation of the density of the light emitting element on the object to be exposed. It is obtained as a maximum value by a transfer function.

  According to a fifth aspect of the present invention, in the method for adjusting a focal position of an exposure apparatus according to any one of the first to third aspects, the focal position is a beam diameter of the light emitting element on the object to be exposed. It is obtained as a minimum value.

  According to a sixth aspect of the present invention, in the method for adjusting a focal position of an exposure apparatus, a substrate on which a plurality of light emitting elements are arranged in a line and a light emitted from the light emitting elements are imaged on an object to be exposed. An image element; a support member that supports at least one of the substrate and the imaging element; and a focus position adjusting unit that moves the support member in a direction in which the support member is moved toward and away from the object to be exposed. A regression line is obtained from the focal position data on the coordinates where the focal position of the light emitting element is obtained, and the focal position is based on at least one of the inclination of the regression line and the relationship between the regression line and the distance between the exposure object and the object. The position of the support member is adjusted by the adjusting means.

  According to the sixth aspect of the present invention, at least one of the substrate on which the plurality of light emitting elements are arranged in a row and the imaging element that forms an image of light emitted from the light emitting elements on the object to be exposed is supported by the support member. Is done. Then, the focal position of the light emitting element is adjusted by the focal position adjusting means for moving the imaging element in the direction in which the imaging element is moved toward and away from the object to be exposed.

  That is, a regression line is obtained from the focal position data on the coordinates where the focal position of each light emitting element is obtained, and the focal position is determined based on at least one of the inclination of the regression line and the relationship between the regression line and the distance between the exposure line and the object to be exposed. By adjusting the position of the support member with the adjusting means, the focal position of the light emitting element can be set on the surface of the object to be exposed, and the density unevenness of the image device caused by the variation in the focal position of the light emitting element can be reduced. it can.

  As described above, according to the present invention, it is possible to reduce the density unevenness of the image device caused by the variation in the focal position of the light emitting element.

  An LED head as an exposure apparatus according to an embodiment of the present invention will be described.

  As shown in FIG. 1, an LED head 100 is used in an image forming apparatus 10 that forms an image on a recording medium such as recording paper by an electrophotographic method.

  In the image forming apparatus 10, a drum-type electrophotographic photosensitive member as an image carrier, that is, a photosensitive drum 12, is supported so as to be rotatable about an axis G. The surface of the photosensitive drum 12 rotating in the arrow K direction is charged by the charging device 14. The charged photosensitive drum 12 is exposed to light corresponding to image information emitted from the LED head 100 as an exposure device, whereby an electrostatic latent image is formed. This electrostatic latent image is developed by the developing device 16 to form a toner image on the photosensitive drum 12.

  When the recording paper stored in the paper tray (not shown) is transported along the paper transport path P, the toner image formed on the photosensitive drum 12 described above is transported by the transfer device 18. Transferred to paper. The recording sheet on which the toner image has been transferred is conveyed to a fixing device (not shown), and after the toner image is fixed, the recording paper is discharged out of the device. Residual toner remaining without being transferred is removed by the cleaning device 20 and discharged by the charge removing device 22.

  As shown in FIGS. 1 and 2, the entire LED head 100 has a quadrangular prism shape, and the longitudinal direction thereof is the same as the axis G of the photosensitive drum 12. Further, the LED head 100 includes a support member 102 made of a metal, and the support member 102 includes a substrate support portion 104 having a quadrangular cross section.

  A first substrate 150 is attached to the upper surface 104A of the substrate support portion 104, and an LED array 152 as a light emitting element is disposed on the upper surface of the first substrate 150 in the longitudinal direction (in the direction of the axis G of the photosensitive drum 12). ) Are mounted side by side.

  Here, the LED array 152 is a so-called self-scanning LED (SLED) array that has a light emitting thyristor having a PNPN structure and the LED array 152 itself has a shift register function. This self-scanning LED array can significantly reduce the number of signal lines to be connected as compared to a non-self-scanning LED array. Therefore, the first substrate 150 can be reduced in size.

  A second substrate 170 is attached to the lower surface 104B opposite to the upper surface 104A of the substrate support portion 104, and various electronic components 176 (see FIG. 3, capacitors and resistors) are attached to both surfaces of the second substrate 170. Etc. are implemented. A driving element 172 that drives the LED array 152 mounted on the first substrate 150 and a connector 174 that is electrically connected to the outside are mounted on the lower surface of the second substrate 170. Note that the width of the second substrate 170 (the direction orthogonal to the longitudinal direction, the direction orthogonal to the rotation axis G direction of the photosensitive drum 12) is wider than that of the first substrate 150 (see FIG. 1).

  The first substrate 150 and the second substrate 170 are electrically connected by a flexible wiring substrate 190. The flexible wiring substrate 190 is formed by thermocompression bonding or thermocompression bonding of an anisotropic conductive film. And it is connected to the outer surface together with the second substrate 170. Note that the LED array 152 is a self-scanning LED array, and the number of signal lines to be connected is significantly smaller than that of a non-self-scanning LED array. Therefore, the flexible wiring board 190 can also be narrowed.

  On the other hand, as shown in FIG. 3, a recess 104 </ b> C in which various electronic components 176 (capacitors and resistors) are accommodated is formed on the lower surface 104 </ b> B of the substrate support portion 104. However, the recess 104C is not formed in the region where the drive element 172 is mounted. Therefore, in the area where the driving element 172 is mounted on the upper surface of the second substrate 170, the lower surface 104B of the substrate support portion 104 of the support member 102 is in surface contact, and the thermal conductivity is good and the heat dissipation effect is high.

  As shown in FIGS. 1 and 2, the imaging element support portion 106 extends from the upper surface 104 </ b> A of the substrate support portion 104 toward the photosensitive drum 12 (see FIG. 1). The imaging element support unit 106 has a distributed refractive index lens for imaging the light emitted from the LED array 152 onto the photosensitive drum 12, so-called Selfoc lens 90A ("Selfoc" is registered by Nippon Sheet Glass Co., Ltd.). A lens array 90 is attached. A resin cover 108 is also attached to the upper surface 104A of the substrate support portion 104 so that the first substrate 150 is not exposed, as shown by an imaginary line (a two-dot broken line) in FIGS. Yes.

  As shown in FIGS. 2 and 4, insertion holes 110 and 111 penetrate vertically on both outer sides of the substrate support portion 104 of the support member 102 in the longitudinal direction to which the first substrate 150 is attached. Screw hole portions 110 </ b> A and 111 </ b> A are formed on the lower surface 104 </ b> B side of the substrate support portion 104. The adjustment pins 112 and 113 can be inserted into the insertion holes 110 and 111, and screw portions 112A and 113A are formed at the bases of the adjustment pins 112 and 113, and can be screwed into the screw hole portions 110A and 111A. It has become.

  Furthermore, screw holes 120 and 121 are formed on the side surface of the substrate support portion 104 of the support member 102 in a direction orthogonal to the insertion holes 110 and 111, and the tips of the screw holes 120 and 121 are connected to the insertion holes 110 and 111. It is connected. And set screw 122,123 is screwed in this screw hole 120,121.

  As shown in FIG. 4, by tightening the set screws 122 and 123 with the adjustment pins 112 and 113 protruding from the upper surface 104 </ b> A of the substrate support portion 104, the tips of the set screws 122 and 123 are adjusted. The side surfaces of 112 and 113 are pressed, and the adjustment pins 112 and 113 are fixed.

  Here, as shown in FIG. 3, the support member 102 is urged toward the photosensitive drum 12 (see FIG. 1) by the urging spring 24, and the tips of the fixed adjustment pins 112 and 113 are used for image formation. A distance between the photosensitive drum 12 and the LED head 100 is determined by hitting the positioning unit 26 provided in the apparatus 10.

That is, the protruding amounts M ₁ and M _{2 of} the adjustment pins 112 and 113 protruding from the upper surface 104A of the substrate support portion 104 (H ₁ and H ₂ with reference to the lower surface 104B of the substrate support portion 104 of the LED head 100) are adjusted. Thus, the focal position of the LED head 100 can be adjusted by adjusting the distance between the photosensitive drum 12 and the LED head 100.

Next, an adjustment method (an adjustment method of the focal position of the LED head 100) for adjusting the distances H ₁ and H ₂ from the lower surface 104B of the substrate support portion 104 of the LED head 100 to the tips of the adjustment pins 112 and 113 will be described.

  First, in step 100 of FIG. 5, as shown in FIG. 6, an MTF (black and white line width chart) is measured with respect to the light emission position of each LED array 152 of the LED head 100 measured from the lower surface 104 </ b> B of the substrate support unit 104. The ratio of how much the contrast of the chart image has decreased is shown, and the maximum focal position based on the so-called modulation transfer function is obtained (maximum focal position data (hereinafter referred to as “MTF data S”). In step 102, the MTF data S of each LED array 152 is read.

Next, in step 104, the read MTF data S is plotted as shown in FIG. 7 on the coordinate system having the origin at the point where the line passing through the adjustment pin 112 and the surface position of the photosensitive drum 12 intersect (MTF data S). ₁ ) A regression line P is obtained by the least square method (Z = aX + b). In step 106, the deviation amounts h ₁ and h ₂ at the positions of the adjustment pins 112 and 113 are calculated from the regression line P. Accordingly, h ₁ = b (X = 0) and h ₂ = aR + b (X = R) are obtained.

Next, in step 108, so that the slope and intercept of the regression line P becomes "0", the correction of MTF data S ₁ and regression line P (as shown in FIG. 8, a corrected MTF data S ₂ and the regression line Q). Next, in step 110, calculates the maximum value of the MTF data _{S 2} after the correction (Max) and the minimum value (Min) from the median of the MTF data _{S 2 (M) (M =} (Max + Min) / 2) .

Then, in step 112, calculates a distance of the minimum value of MTF data _{S 2} after the correction and (Min) and Z = 0 (N), in step 114, the regression line Q coincides with the median (M) The distance OS (OS = M−N) when moving in this way is calculated (see FIG. 8).

Next, in step 116, so that the distance to the regression line to _{Q 1} after moving the tip of the adjusting pin 112, 113 is the focal point of the LED array 152, the adjustment from the lower surface 104B of the substrate supporting portion 104 of the LED head 100 The distances H ₁ and H ₂ (see FIG. 3) to the tips of the pins 112 and 113 are calculated.

H ₁ = H ₁ ′ + h ₁ = (Q) + (OS) − (P) + h ₁ (Expression 1)
H ₂ = H ₂ ′ + h ₂ = (Q) + (OS) − (P) + h ₂ (Formula 2)
Here, P is the distance from the tips of the adjustment pins 112 and 113 to the focal position of the LED array 152, which is a so-called design value.

Next, in step 118, the adjustment pins 112 and 113 are rotated so that the distances from the lower surface 104B of the substrate support portion 104 of the LED head 100 to the tips of the adjustment pins 112 and 113 become H ₁ and H ₂ , respectively. To do. In step 120, the set screws 122 and 123 shown in FIG. 5 are tightened, the side surfaces of the adjustment pins 112 and 113 are pressed, and the adjustment pins 112 and 113 are fixed. Through the adjustment as described above, the focus of the LED array 152 can be adjusted to the surface of the photosensitive drum 12.

  In addition, it is preferable to apply an adhesive as a screwing agent for preventing looseness to the set screws 122 and 123 because the positions of the adjustment pins 112 and 113 are less likely to shift after being fixed. Moreover, as an adhesive agent, the anaerobic adhesive agent which hardens | cures when air is interrupted | blocked is suitable.

  Next, the operation of this embodiment will be described.

As shown in FIG. 5, by adjusting the distances H ₁ and H ₂ from the lower surface 104B of the substrate support portion 104 of the LED head 100 to the tips of the adjustment pins 112 and 113, the photosensitive drum 12 and the LED head 100 can be adjusted. Although the interval can be adjusted, the screw head portions 110A and 111A are formed in the LED head 100 itself, and the adjustment pins 112 and 113 are screwed into the screw hole portions 110A and 111A, thereby adjusting the position of the LED head 100. I can do it.

  In this way, by forming an adjustment function for adjusting the position of the LED head 100 in the LED head 100 itself, it is not necessary to provide a complicated position adjusting device in the LED head 100, and the LED head 100 does not become large. Further, since the position of the LED head 100 can be adjusted by the screwing amounts of the adjustment pins 112 and 113, the adjustment is easy. Further, since no complicated mechanism is used, the cost is low.

Next, since the focal positions of the plurality of arrayed LED arrays 152 vary, in this embodiment, first, a regression line P is obtained on the coordinates from the MTF data S obtained for the focal positions of the LED arrays 152. as the slope and intercept of the regression line P becomes "0", the correction of MTF data _{S 1} and regression line P (corrected; MTF data _{S 2} and regression line Q).

Then, the median value (M) of the corrected MTF data S ₂ is calculated, the distance OS from the regression line Q is calculated, and the adjustment pins 112, 113 from the lower surface 104 B of the substrate support 104 of the LED head 100. The distances H ₁ and H ₂ to the tip of are calculated. The positions of the tips of the adjustment pins 112 and 113 are adjusted so that the distances from the lower surface 104B of the substrate support portion 104 of the LED head 100 to the tips of the adjustment pins 112 and 113 are H ₁ and H ₂ , respectively.

Here, as shown in FIG. 8, since the regression line Q itself is also not in the center of the variation of MTF data S _2, the distance OS component median MTF data S ₂ (M) and the regression line Q By adjusting the position of the LED head 100 by adding or dividing, it is possible to prevent large density unevenness from occurring in the image forming apparatus 10. That is, it is possible to adjust the focal position with high robustness.

Depending on the variations in the MTF data _{S 2,} the correction distances OS partial median MTF data _{S 2} (M) and the regression line Q is not necessarily required.

  Then, by incorporating the algorithm shown in FIG. 5 in the control software of the image apparatus, automation can be facilitated and productivity can be improved.

  In this embodiment, the maximum value by the modulation transfer function of the density of the LED array 152 on the photosensitive drum 12 is measured as the focal position. However, it is sufficient that the focal position of the LED array 152 can be measured. The minimum value of the beam diameter of the LED array 152 on the body drum 12 may be measured.

  Further, the present invention is not limited to the above embodiment. For example, in the above embodiment, the object to be exposed is the drum-shaped photosensitive drum 12, but it may be a belt-shaped belt photosensitive member.

It is a figure which shows typically the principal part of an image forming apparatus provided with the LED head which concerns on embodiment of this invention. It is a perspective view which shows typically the LED head which concerns on embodiment of this invention. It is a front view which shows typically the LED head which concerns on embodiment of this invention. It is sectional drawing of the LED head which concerns on embodiment of this invention. It is a flowchart which shows the adjustment method which adjusts the focus position of the LED head which concerns on embodiment of this invention. It is a figure explaining the focal position data of a LED head. It is explanatory drawing explaining the method to correct | amend the focus position data of a LED head. It is explanatory drawing explaining the method to correct | amend the focus position data of a LED head.

Explanation of symbols

10 Image forming apparatus 90 Lens array (imaging element)
100 LED head (exposure device)
102 Support member 104 Substrate support part (support member)
110A First screw hole (focal position adjusting means)
111A First screw hole (focal position adjusting means)
112 Adjustment pin (focal position adjustment means)
113 Adjustment pin (Focus position adjustment means)
120A Second screw hole (focal position adjusting means)
121A Second screw hole (focal position adjusting means)
122 set screw (fixing screw, focus position adjusting means)
123 set screw (fixing screw, focus position adjusting means)
150 First substrate (substrate)
152 LED array (light emitting device)
P regression line Q regression line Q ₁ regression line S MTF data (focus position data)
S ₁ MTF data (focus position data)
S ₂ MTF data (focus position data)

Claims (6)

A substrate on which a plurality of light emitting elements are arranged in a line;
An imaging element that forms an image of the light emitted from the light emitting element on an object to be exposed;
A support member that supports at least one of the substrate and the imaging element;
A focus position adjusting means for moving the support member in a direction in which the support member is moved toward and away from the object to be exposed;
With
When a regression line is obtained from the focal position data on the coordinates for obtaining the focal position of each light emitting element, and the slope of the regression line is set to 0, the focal position of the light emitting element on the regression line is the surface of the object to be exposed. The focus position adjusting method of the exposure apparatus, wherein the position of the support member is adjusted by the focus position adjusting means.   The median value of the focal position data is calculated from the maximum value and the minimum value of the focal position data when the slope of the regression line is set to 0, and the adjustment of the support member is performed from the amount of deviation between the median value and the regression line. 2. The focus position adjusting method for an exposure apparatus according to claim 1, wherein the amount is corrected. The focal position adjusting means is
A first screw hole formed in the support member along a direction in which the imaging element is moved toward and away from the object to be exposed;
An adjustment pin which is provided so as to be screwable into the first screw hole, and whose tip is in contact with a main body side frame which supports the object to be exposed, and which makes the support member contact and separate from the object to be exposed;
A second screw hole formed in a direction orthogonal to the first screw hole and connected to the first screw hole;
A fixing screw that is screwed into the second screw hole and presses a side surface of the adjustment pin to fix the adjustment pin;
The method of adjusting a focal position of an exposure apparatus according to claim 1 or 2, wherein the focal position adjustment method is an exposure apparatus.   The focal position of the exposure apparatus according to claim 1, wherein the focal position is obtained as a maximum value by a modulation transfer function of the density of the light emitting element on the object to be exposed. Adjustment method.   4. The method of adjusting the focal position of an exposure apparatus according to claim 1, wherein the focal position is obtained as a minimum value of a beam diameter of the light emitting element on the object to be exposed. A substrate on which a plurality of light emitting elements are arranged in a line;
An imaging element that forms an image of the light emitted from the light emitting element on an object to be exposed;
A support member that supports at least one of the substrate and the imaging element;
A focus position adjusting means for moving the support member in a direction in which the support member is moved toward and away from the object to be exposed;
With
Obtaining a regression line from the focal position data on the coordinates for determining the focal position of each light emitting element, based on at least one of the inclination of the regression line and the relationship between the regression line and the distance between the exposed body and the object A method for adjusting a focal position of an exposure apparatus, wherein the position of a support member is adjusted by a focal position adjusting means.

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