JP2002052757A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus which can prevent generation of streaks, etc., to images due to a positional deviation of a plurality of linear solid image exposure element arrays caused by a thermal expansion or the like even in the case where the plurality of linear solid image exposure element arrays are connected to dividedly expose an entire image width of a wide image carrier. SOLUTION: The plurality of linear solid image exposure element arrays of this imaging apparatus are arranged along an axial direction of the image carrier so that at least adjacent solid image exposure element arrays are made positionally different in a rotational direction of the image carrier. The entire image width of the image carrier is thus dividedly exposed by the plurality of solid image exposure element arrays to form images. The apparatus is provided with a positional deviation- detecting means for detecting the deviation of at least one of the position in the axial direction of the image carrier of, the position in the rotational direction of the image carrier of, and a focal point position of each of the solid image exposure element arrays, and a correcting means for correcting an image exposure state of the plurality of solid image exposure element arrays on the basis of the detected result by the positional deviation-detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer to which an electrophotographic system is applied, and more particularly to an image forming apparatus capable of forming a large-sized image such as A0 size or A1 size. It is.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus capable of forming a large-sized image such as A0 size or A1 size, a laser beam emitted from a semiconductor laser is used as an image exposing means for exposing an image on a photosensitive drum. The beam is deflected and scanned by a polygon mirror, and the laser beam deflected and scanned by the polygon mirror is scanned and exposed on a photosensitive drum via an f-θ lens and a mirror, a so-called RO.
Rather than S (Raster Output Scanner), a solid image exposure element array in which solid image exposure elements such as LEDs are linearly arranged like an LED print head is generally used. The reason is A0
In an image forming apparatus capable of forming a large-sized image such as a size, when an ROS that deflects and scans a laser beam with a polygon mirror is used as an image exposure unit, the number of pixels in one line corresponding to an A0 size or the like Is significantly higher than that of a small-sized image forming apparatus.Therefore, it is necessary to greatly increase the modulation frequency of the semiconductor laser and to significantly increase the rotation speed of the polygon mirror. It is difficult to apply because of its limitations.

Therefore, in an image forming apparatus capable of forming a large-sized image such as the A0 size, a linear solid-state image exposure element array such as an LED print head is used as image exposure means. As described above, when a linear solid-state image exposure element array such as an LED print head is used as the image exposure means, the linear solid-state image exposure element array such as the LED print head is
It must be arranged over the image width of the photosensitive drum corresponding to 0 size or the like, and a long LED print head is required.

However, a long LED print head corresponding to the A0 size or the like requires an LED element or a driver I / O.
Since the number of arrays of C and the like increases, the alignment accuracy and production yield decrease rapidly in manufacturing, and the unit cost of the components becomes significantly higher than that of a small-sized one, resulting in a significant increase in cost of the image forming apparatus. There was a problem of inviting.

[0005] As a technique capable of solving such a problem, Japanese Patent Application Laid-Open Nos. Hei 10-157191 and Hei 6-157191 are known.
No. 255175, or JP-A-6-105071
Some are disclosed in Japanese Patent Application Publication No. This Japanese Patent Laid-Open No. 10
An image forming apparatus according to Japanese Unexamined Patent Application Publication No. 157191 discloses an image forming apparatus including a rotatable photoconductor and an exposure unit configured to expose a surface of the photoconductor to form an electrostatic latent image. Exposure is performed by dividing the maximum photosensitive width in the axial direction of the photoreceptor by a plurality of rows of solid linear writing devices arranged at different positions in the rotation direction of the photoreceptor along the axial direction of the photoreceptor. The solid-state linear writing devices arranged at the most downstream position in the rotation direction of the photoconductor are provided with image information delay control means for delaying image information.

Further, the recording apparatus according to the above-mentioned Japanese Patent Application Laid-Open No. 6-255175 uses a plurality of recording heads, each of which has a recording element arranged in a line, and connects the ends of these recording heads to perform the recording. These recording heads are arranged so that the elements are substantially in line with the line direction, and the recording elements of the two recording heads are present at a predetermined connection length or more in parallel with the line direction at these joined connection portions. A recording head unit, image signal supply means for supplying an image signal for recording to the recording head unit, and an image signal from one recording head recording element to the other recording head recording element of the connection unit. An image signal switching position setting means for setting a switching position at random for each scanning line is provided.

Further, in the mounting structure for an electro-optical device according to the above-mentioned Japanese Patent Application Laid-Open No. 6-105071, the positional relationship between the boundaries of the operating ranges of the individual devices is maintained irrespective of the thermal expansion of the device or the base. Mounting structures for a plurality of elongate electro-optical devices arranged along lines on a common substrate, such that the electro-optical devices have an operating range slightly less than the length of each device and their operating ranges. Staggered with overlapping end portions so that the areas are adjacent to each other;-two adjacent ends of the device are fixed on the substrate such that the operating ranges of these two devices are adjacent in a reference position; The other end of the device is free to move longitudinally relative to the substrate,
A spacer having a length and a coefficient of thermal expansion matched to the electro-optical device is fixed at one end near the reference position, the other end of the spacer is free to move longitudinally, the third electron,
One end of the optical device is configured to be held in engagement with the free end of the spacer.

[0008]

However, the prior art described above has the following problems. That is, in the case of the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. H10-157191, an exposure unit that exposes the surface of a photoreceptor to form an electrostatic latent image is provided along the axis of the photoreceptor. A plurality of rows of solid linear writing devices arranged at different positions in the body rotation direction are configured to divide the maximum photosensitive width in the axial direction of the photosensitive body and expose the photosensitive body. . Therefore, solid line writing devices such as a plurality of rows of LED print heads generate heat and expand due to image exposure, so that the dot positions at the joints of the plurality of rows of solid line writing devices are shifted. When uniform halftone is output, if the joint of the solid line writing device widens, it becomes white streaks, and if it narrows, it becomes black streaks, and the image becomes uneven, such as white streaks and black streaks. Had a point. Further, when the dot misalignment is large, there is a problem that the dot positional relationship at the joint of the solid line linear writing devices in a plurality of rows is reversed, and the images are overlapped.

In the case of the printing apparatus disclosed in Japanese Patent Laid-Open No. 6-255175, image information of an overlapping portion of a seam of a printing head is not transferred from one printing head to the other printing head for each scanning line. By switching to random (random) operation, the deviation of the dot positional relationship at the joint of the recording heads is made inconspicuous. However, the dot positional relationship of the recording heads is not actively controlled properly, and The problem is that the unevenness and the level difference between the joints are only made inconspicuous, and the unevenness and the level difference between the recording heads cannot be eliminated, and the image quality is not satisfactory.

Further, in the case of the mounting structure for an electro-optical device according to the above-mentioned Japanese Patent Application Laid-Open No. 6-105071, a spacer having a length and a coefficient of thermal expansion matched to the electro-optical device is provided. By intervening between the apparatuses, the change in the positional relationship of the connecting dots due to thermal expansion is reduced, but again, the dot positional relationship of the recording head is not properly controlled, and the connecting of the recording heads is not performed. The problem is that the unevenness and the level difference are only made inconspicuous, and the unevenness and the level difference at the joint of the recording heads cannot be eliminated, and the image quality is not satisfactory.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to connect a plurality of linear solid-state image exposure element arrays to thereby obtain a width. However, even if the entire image width of an image carrier is divided and image exposure is performed, the image may be streaked due to misalignment of a plurality of linear solid-state image exposure element arrays due to thermal expansion or the like. An object of the present invention is to provide an image forming apparatus capable of preventing occurrence of unevenness or the like.

[0012]

That is, according to the first aspect of the present invention, a plurality of linear solid-state image exposure element arrays are positioned at least in the rotational direction of the image carrier of the adjacent solid-state image exposure element arrays. Are arranged along the axial direction of the image carrier, and the entire image width of the image carrier is divided and exposed by the plurality of solid-state image exposure element arrays to form an image. In the forming apparatus, a displacement detection unit configured to detect at least one of a position in an axial direction and a rotation direction of an image carrier of each of the solid-state image exposure element arrays and a focal position, and a detection result of the position displacement detection unit Correction means for correcting the image exposure state of the plurality of solid-state image exposure element arrays based on the above.

According to a second aspect of the present invention, the displacement detecting means causes a predetermined number of solid-state image exposure elements located near at least one end of each solid-state image exposure element array to emit light. 2. The image forming apparatus according to claim 1, wherein a position shift of the solid image exposure element array is detected by detecting a light emitting position of the solid image exposure element.

Further, according to a third aspect of the present invention, the position shift detecting means causes the solid-state image exposing elements located near at least one end of each solid-state image exposing element array to emit light, and Forming an electrostatic latent image on the surface of the solid-state image, developing the electrostatic latent image to form a toner image, and detecting the position of the toner image, thereby detecting the displacement of the solid-state image exposure element array. The image forming apparatus according to claim 1, wherein:

[0015] Still further, the invention described in claim 4 is:
The position shift detecting means, between each solid image exposure element array and the image carrier, a light receiving element is directly arranged, or a light guide member that guides light from each solid image exposure element array to the light receiving element is arranged. 3. The image forming apparatus according to claim 1, wherein the position of the solid-state image exposure element array is detected by the light receiving element.

According to a fifth aspect of the present invention, in the image processing apparatus, the position shift detecting means includes a step of setting the solid image exposure elements located near at least one end of each solid image exposure element array by a predetermined number of the solid image exposure elements. The solid-state image exposure device array is sequentially turned on along the axial direction of the image carrier, and the amount of light emitted from the solid-state image exposure device is detected by a light-receiving element, thereby displacing the solid-state image exposure device array along the axial direction of the image carrier. The image forming apparatus according to claim 1, wherein the image forming apparatus detects an error.

According to a sixth aspect of the present invention, in the image processing apparatus, the position shift detecting means may be configured such that the solid-state image exposing elements located near at least one end of each solid-state image exposing element array are separated by a predetermined number of solid-state image exposing elements. , Sequentially turn on along the axial direction of the image carrier, the light emission amount of the solid-state image exposure element, through a slit inclined along the rotation direction of the image carrier,
2. The image forming apparatus according to claim 1, wherein a position shift of the image carrier of the solid-state image exposure element array along a rotation direction is detected by detecting the light receiving element.

According to a seventh aspect of the present invention, in the image forming apparatus, the position shift detecting means includes a solid image exposing element located near at least one end of each solid image exposing element array and a predetermined number of solid image exposing elements. As one set, the solid-state image exposure elements are simultaneously turned on along the axial direction of the image carrier at different gradations for each set of the solid-state image exposure elements, and the amount of light emitted from the solid-state image exposure elements is detected by a light-receiving element. 2. The image forming apparatus according to claim 1, wherein a displacement of the image carrier of the image exposure element array along the axial direction is detected.

According to an eighth aspect of the present invention, in the image forming apparatus, the position shift detecting means includes a solid image exposing element located near at least one end of each solid image exposing element array and a predetermined number of solid image exposing elements. As a set, the solid-state image exposure elements are simultaneously turned on along the axial direction of the image carrier at different gradations for each set of the solid-state image exposure elements, and the light emission amount of the solid-state image exposure elements is set along the rotation direction of the image carrier. 2. The image forming apparatus according to claim 1, wherein a position shift of the image carrier of the solid-state image exposure element array along the rotation direction is detected by detecting the light receiving element through the slit inclined. is there.

According to a ninth aspect of the present invention, the position shift detecting means turns on the solid-state image exposing elements located near at least one end of each solid-state image exposing element array, and causes the solid-state image exposing elements to be mounted on the image carrier. Form a pattern for detecting displacement,
By detecting the position shift detection pattern,
2. The image forming apparatus according to claim 1, wherein a positional shift of the image carrier of the solid-state image exposure element array along the axial direction and the rotation direction is detected.

According to a tenth aspect of the present invention, the position shift detecting means includes a predetermined number of solid-state elements located near the end of one of the two adjacent solid-state image exposure element arrays. While extinguishing the image exposing element, a predetermined number of solid image exposing elements of the other solid image exposing element array located near the lighting position of the one solid image exposing element array are continuously lit, and the other solid By sequentially moving the lighting position of the image exposure element array along the axial direction of the image carrier, a linear image is sequentially formed along the rotation direction of the image carrier, and the one of the one lights is turned off. Detecting a positional shift of the solid-state image exposure element array along the axial direction of the image carrier by detecting a reflectance on a straight line corresponding to the position of the solid-state image exposure element array. 1 is an image forming apparatus according.

According to an eleventh aspect of the present invention, the position shift detecting means includes a predetermined number of solid-state elements located near an end of one of the two adjacent solid-state image exposure element arrays. While continuously lighting the image exposure elements, continuously lighting a predetermined number of solid image exposure elements of the other solid image exposure element array located near the lighting position of the one solid image exposure element array, By sequentially moving the other solid image exposure element array itself along the axial direction of the image carrier, a linear image is formed sequentially along the rotation direction of the image carrier, and the reflectance of the linear image is changed. 2. The image forming apparatus according to claim 1, wherein a positional shift of the image carrier of the solid-state image exposure element array along the axial direction is detected by detecting the positional deviation.

According to a twelfth aspect of the present invention, the position shift detecting means includes a predetermined number of solid-state elements located near an end of one of the two adjacent solid-state image exposure element arrays. While continuously lighting the image exposure elements, turning off only a predetermined number of solid image exposure elements of the other solid image exposure element array located near the lighting position of the one solid image exposure element array and turning off the other solid state By turning on the image exposure element and sequentially moving the other solid image exposure element array itself along the axial direction of the image carrier, a linear image along the rotation direction of the image carrier is formed. Formed at predetermined intervals along the direction of rotation of the body,
By detecting the reflectance at the position where the linear image along the rotation direction of the image carrier and the linear image along the axial direction of the image carrier intersect, the image of the solid-state image exposure element array is detected. 2. The image forming apparatus according to claim 1, wherein a displacement of the carrier along the axial direction is detected.

According to a thirteenth aspect of the present invention, the position shift detecting means turns on the solid-state image exposing elements located near at least one end of each solid-state image exposing element array and places the solid-state image exposing elements on the image carrier. 2. The image according to claim 1, wherein a predetermined image is formed, and a predetermined image formed on the image carrier is detected to detect a positional shift of a focal position of the solid-state image exposure element array. It is a forming device.

According to a fourteenth aspect of the present invention, the position shift detecting means rotates each solid image exposure element array to a position shift detection position different from the image exposure position of the image carrier.
By the light receiving element arranged at the position shift detection position,
2. The image forming apparatus according to claim 1, wherein a position shift of the solid image exposure element array is detected by detecting a light emission position of the solid image exposure element.

According to a fifteenth aspect of the present invention, the correcting means moves the solid-state image exposing element array in at least one of the axial direction and the rotating direction of the image carrier by a moving means, whereby the solid-state image exposing element is moved. 2. The image forming apparatus according to claim 1, wherein an exposure position of the element array is corrected.

The invention according to claim 16 is characterized in that the moving means is made of a shape memory alloy which is connected to an end of the solid-state image exposure element array and contracts by energization. It is a forming device.

According to a seventeenth aspect of the present invention, the moving means is connected to a shape memory alloy which is connected to one end of the solid-state image exposure element array and contracts by energization, and is connected to the other end. 17. The image forming apparatus according to claim 16, comprising a tension spring.

The invention described in claim 18 is characterized in that the moving means is made of a shape memory alloy which is connected to both ends of the solid-state image exposure element array and contracts by energization. An image forming apparatus according to any one of the preceding claims.

According to a nineteenth aspect of the present invention, the moving means includes a cam arranged to be engaged with at least one end of the solid-state image exposure element array, and sandwiches a rotation center of the cam. By connecting a shape memory alloy that contracts by energization to both sides in the radial direction, and selectively energizing the shape memory alloy, the shape memory alloy is contracted to rotate a cam, and the solid image exposure element 2. The image forming apparatus according to claim 1, wherein the skew position of the array is corrected.

According to a twentieth aspect of the present invention, when the solid-state image exposing element array is divided into a plurality of blocks and turned on, the correcting means comprises a plurality of blocks of the solid-state image exposing element array. 2. The image forming apparatus according to claim 1, wherein a position shift of one line or less of the solid-state image exposure element array along the rotation direction of the image carrier is corrected by controlling a lighting order of the image forming members.

According to a twenty-first aspect of the present invention, the correction means controls the brightness at the time of lighting a solid-state image exposure element located near at least one end of each solid-state image exposure element array. 2. The image forming apparatus according to claim 1, wherein the displacement of the solid-state image exposure element array along the axial direction of the image carrier is corrected.

According to a twenty-second aspect of the present invention, the correction means controls the lighting area of the solid-state image exposure element array to thereby control the exposure position of the solid-state image exposure element array along the axial direction of the image carrier. The image forming apparatus according to claim 1, wherein the correction is performed.

According to a twenty-third aspect of the present invention, the correction means includes a lighting start position of each solid-state image exposure element array in accordance with a shift amount of each solid-state image exposure element array in the main scanning direction.
2. The image forming apparatus according to claim 1, wherein the exposure position of the solid-state image exposure element array along the axial direction of the image carrier is corrected by controlling the position, the end position, and the switching position of the image data. is there.

According to a twenty-fourth aspect of the present invention, the correction means corrects an angle between a plurality of solid-state image exposure element arrays arranged along a rotation direction of the image carrier, thereby correcting the image carrier. 2. The image forming apparatus according to claim 1, wherein a position shift of the solid-state image exposure element array along a rotation direction of the image carrier due to a rotation fluctuation of the body is corrected.

According to a twenty-fifth aspect of the present invention, the correcting means corrects the mounting angle of the plurality of solid-state image exposure element arrays along the rotation direction of the image carrier, thereby to adjust the rotation direction of the image carrier. 2. The image forming apparatus according to claim 1, wherein the displacement of the focal positions of the plurality of solid-state image exposure element arrays arranged along the line is corrected.

According to a twenty-sixth aspect of the present invention, in the image carrier, a plurality of linear solid-state image exposure element arrays are arranged such that at least positions of adjacent solid-state image exposure element arrays in the rotation direction of the image carrier are different. In the image forming apparatus for forming an image by arranging along the axial direction of the solid-state image exposure device array and dividing and exposing the entire image width of the image carrier by the plurality of solid-state image exposure element arrays, Correction means for correcting at least one of the axial and rotational positions of the image bearing member of the exposure element array and the focal position; and input means for inputting a correction amount of the correction means. An image forming apparatus characterized in that:

[0038]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 2 shows an image forming apparatus according to Embodiment 1 of the present invention.

In FIG. 2, reference numeral 1 denotes a main body of the image forming apparatus. The inside of the main body 1 of the image forming apparatus is roughly divided into an image forming section 2, a sheet feeding section 3, a control circuit and a spare And a storage unit 4 that stores a paper feed roll and the like.

The image forming section 2 includes a photosensitive drum 5 as an image carrier that is driven to rotate at a predetermined rotational speed along a direction indicated by an arrow by a driving unit (not shown).
As the photoconductor drum 5, for example, a photoconductor drum having a diameter of about 100 mm using a photoconductor made of OPC or the like is used. The surface of the photosensitive drum 5 is uniformly charged to a predetermined potential by a charging roll 6 as a primary charging unit, and then is charged by a plurality of LED print heads 7 ₁ , 7 ₂ , 7 ₃ as an image exposure unit. The image is exposed, and an electrostatic latent image corresponding to the image information is formed. The electrostatic latent image formed on the surface of the photosensitive drum 5 is developed by, for example, a developing device 8 adopting a one-component developing method, and becomes a toner image. Incidentally, the primary charging means for charging the surface of the photosensitive drum 5 is not limited to the charging roll 6, and it goes without saying that a charging device such as a scorotron may be used. Further, the developing device 8 is not limited to the one employing the one-component developing system, but may employ a two-component developing system comprising a toner and a carrier.

The toner image formed on the photosensitive drum 5 is fed from a paper feed roller 9a, 9b corresponding to A0 size or A1 size stored in the paper feed unit 3 to a paper feed roller 10a.
After being transferred by the transfer roll 12 onto the roll paper 11 supplied by the transfer roller 12, the roll paper 11 on which the toner image has been transferred is separated from the surface of the photosensitive drum 5 by the charge removing action of the flat charge remover 13, The sheet is conveyed to the fixing device 15 by the conveying belt 14. Then, the roll paper 11 onto which the toner image has been transferred is subjected to a fixing process by heat and pressure by a fixing device 15 and, if necessary, cut into a predetermined size such as an A0 size.
Is discharged onto a discharge tray (not shown) disposed outside the printer.

After the toner image transfer step is completed, the surface of the photosensitive drum 5 is cleaned of residual toner, paper dust and the like by the cleaning device 16 to prepare for the next image forming step. .

By the way, in this embodiment, the plurality of linear solid-state image exposure element arrays are arranged so that at least the positions of the adjacent solid-state image exposure element arrays in the rotation direction of the image carrier are different. The plurality of solid-state image exposure element arrays are arranged so as to divide the entire image width of the image carrier and perform image exposure.

That is, in this embodiment, FIG.
As shown, three linear LED print heads 7₁,
7_Two, 7_ThreeBut at least the adjacent LED printhead
C7 ₁, 7_Two, 7_ThreeIn the direction of rotation of the photosensitive drum 5
In the axial direction of the photosensitive drum 5 so that the
Along the three LED print heads 7₁,
7_Two, 7_ThreeThe image area of the photosensitive drum 5 is divided by
For image exposure. Each of the above LEDs
Print head 7₁, 7_Two, 7_ThreeFor example,
The one corresponding to A3 size of 12 inches is used
You. In the above embodiment, three LED prints are used.
Head 7₁, 7_Two, 7_ThreeTo explain when
However, the number of LED print heads may be two.
Of course, four or more may be used. Also, LE
Not only D print head, but also EL (electro luminescence)
Sense) Other solid-state image exposure element arrays using elements
May be used.

The three LED print heads 7 ₁ ,
7 _2, 7 _3, as shown in FIG. 1, are disposed on an elongated base 15 made of a metal having a low thermal expansion coefficient such as stainless steel or aluminum. Of the three LED print heads 7 ₁ , 7 ₂ , and 7 ₃ , the first and third Ls
The ED print heads 7 ₁ and 7 ₃ are disposed on a single straight line M at a predetermined distance along the axial direction of the photosensitive drum 5 on the upstream side in the rotation direction of the photosensitive drum 5. I have. The second LED printhead 7 _2, downstream in the rotation direction of the photosensitive drum 5, at a predetermined distance L with respect to the first and third LED print head 7 _1, 7 _3, these first The first and third LED print heads 7 ₁ ,
7 ₃ so as to be positioned in the middle, are arranged along the axial direction of the photosensitive drum 5.

Further, as shown in FIG. 1, the _three LED print heads 7 ₁ , 7 ₂ , and 7 ₃ are located at the right end and the center of the _first print head 71 located at the left end. left end of the print head 7 ₂ 2, and the left end portion of the third print head 7 ₃ positioned at the right end and the right end of the second print head 7 ₂ is disposed so as partially to overlap In addition, image exposure is possible without generating a gap over the entire image width of the photosensitive drum 5. The first effective image exposure region of the LED print head ₇₁ is, as shown in FIG. 3 (a), when X dots, a first LED printhead 7 ₁ and the second LED printhead When 7 ₂ overlap is a Y dot, the ₂ second LED print head 7, X-
The image (printing) data on the position of the Y dots, the second LED printhead 7 ₂ to the image data is to be transferred. Also, the second LED print head 7
₂ and when the third overlap of the LED print head 7 ₃ is Y2 dots, the third LED print head 7 _3, from the image data of the position of the X-Y + X-Y2 dots, the third LED image data is transferred to the print head 7 _3. In addition, instead of using one of the LED print heads of the overlap portion as a print area at all, there is also a method of using the overlap portion halfway as shown in FIG. 3B. In this case, each Y, Y4 dots, a second LED printhead 7 ₂ over an unused area of the first LED print head _71, and the 3 LED print overlapping portion of the head 7 ₃ as shown in FIG. When each Y2, Y3 dots an unused area of the lap portion, the ₂ second LED print head 7, and is transferred from the image data of the position of the X-Y dot. Further, in the third LED print head 7 _3, it is transferred from the image data of the position of the X-Y + X-Y2- Y3 dots. Note that the above three L
The mounting positions of the ED print heads 7 ₁ , 7 ₂ , and 7 ₃ are adjusted as described above at the time of assembly at a factory or the like.

Each of the LED print heads 7 ₁ ,
As shown in FIG. 4, each of 7 ₂ and 7 ₃ includes a print head housing 16. Inside the print head housing 16, LED elements (not shown) arranged linearly and the LED elements Is built in.
Each of the LED print heads 7 ₁ , 7 ₂ , and 7 ₃ can perform image exposure on an image area corresponding to the A3 size, for example, as described above. Further, a selfoc lens (trade name) 17 as an imaging element array is provided integrally on the front side of the print head housing 16 along the longitudinal direction.

FIG. 5 is a sectional view of the LED print head.

The LED print heads 7 ₁ , 7 ₂ , 7
₃ , an insulating substrate 18 is provided inside a print head housing 16 made of a synthetic resin or the like, as shown in FIG. In the direction, an LED element array 19 formed at a predetermined array density (600 dpi) is provided, and a drive circuit 20 for driving the LED element array is provided beside the LED element array 19. . Also,
Above the LED element array 19, selfoc lenses (trade names) 17 are arranged at predetermined intervals in a direction perpendicular to the drawing. This Selfoc lens 1
7 is for condensing the light emitted from each LED element of the LED element array 19 and exposing it to an image forming position corresponding to the focal length from the tip of the SELFOC lens 17 in the form of a plane circular dot. belongs to.

FIG. 6 shows a driving circuit of the one LED print head.

The LED print head 7 is, for example, 1
2 inches wide, array density 600dpi If is constituted by a total of 60 LED chips 28 _{1-28 60} 1-60, each LED chip 28 _{1-28 60,} 128 LED elements linear Is formed. As a result, the LED print head 7 has 60 × 128 = 768.
0 of LED elements have been arranged, is driven by dividing a predetermined LED chip 28 _{1-28 60} each. Note that the 7,680 LED elements of the LED print head 7 are not all used for image exposure, and as described above, one end or both ends may be partially unused.

The LED print head 7 is controlled by the correction control LSI 22 during drive control during printing,
D light amount correction control is performed, and image data signals DATA1 to DATA4 are input to this correction control LSI 22 in four bits. The correction control LSI22, among the 60 pieces of LED driving circuits 21 ₁ to 21 ₆₀ are connected to the shift register 23 ₆₀ and bit correction circuit 26 ₆₀ corresponding to the LED drive circuit 21 _60. The 60 LED drive circuits 21 ₁ to 21
21 ₆₀ is provided with a shift register 23, respectively,
Each shift register 23 has a latch circuit 24 and an AND circuit.
The circuit 25, the bit correction circuit 26, and the driver 27 are connected to each other. Further, each LED driver circuits 21 ₁ to 21 ₆₀ includes a shift register 23, latch circuit 24, the AND circuit 25, the bit correction circuit 26 to each other are connected respectively, in the figure, 60 th LED drive positioned at the left end from circuit 21 _60, and image data, Russia - de signal LOAD or four strobe signals STRB1~4 active low, it is configured to be sequentially transferred to the first LED driving circuit 21 _1. Further, an LED chip 28 on which 128 LED elements are formed is connected to each driver 27, and the anode terminal of each LED element is connected to the LED ground.

When printing, as shown in FIG. 7, the print data signals DATA1 to DATA4 are sequentially shifted to the respective shift registers in synchronization with the fall of the clock signal CLOCK. At this time, the print data signals DATA1 to DATA4 are 1
For each clock signal CLOCK, the print data of four dots is shifted as one unit, such as 1, 2, 3, 4 dots, and the print data of the first line is 60 pieces at the clock of 7680/4 = 1920. Are sequentially transferred to the shift register. After that, the load signal LOAD becomes “H”.
, The first line print data sequentially shifted to the 60 shift registers is transferred to the latch circuit 24, and the second line print data is sequentially shifted to the 60 shift registers 23.

The LED elements on each LED chip 28 of the LED print head 7 generate a strobe signal S
While TRB1 to TRB4 are active low, the print data latched by the latch circuit 24
The data is sent to the driver 27 via the 5 and bit correction circuit 26, each LED element is turned on in accordance with the print data, and image exposure is performed. At this time, in the LED print head 7, not all the LED elements are turned on at the same time, but 15 strobe signals STRB1 to STRB4 input to the AND circuit 25, as shown in FIG. , Which are divided into four parts and sequentially lit.

The LED print head 7 is driven as described above, and the surface of the photosensitive drum 5 is subjected to image exposure as shown in FIG. However, the above L
It is known that the ED print head 7 undergoes thermal expansion or contraction due to the heat generated by the lighting of the LED element and the change (rise or fall) in the environmental temperature.
In the case of the print head 7, L
The exposure position of the ED element changes along the axial direction of the photosensitive drum 5. Further, the LED print head is warped due to factors such as thermal deflection, and there is also a fluctuation in the exposure position in the rotation direction of the photosensitive drum 5 and a fluctuation in the focal position in the normal direction. However, the first
LED in the print head ₇₁ at the left end and the right end portion of the third LED print head 7 _3, even if the exposure position of the LED element is slightly shifted in accordance with the thermal expansion or thermal contraction, the image left or right direction Just move slightly to
This is not a problem as a defect in image quality. In contrast, the first LED print head ₇₁ of the right end, both end portions of the second LED print head 7, _second and third LE
The left end of the D print head 7 _3, for performing image exposure by connecting the LED print head 7, the exposure position of the LED element also is displaced slightly, white streaks and black streaks, or be a step of line drawing, image defects Cause.

Therefore, in this embodiment, a displacement detecting means for detecting at least one displacement of the position of the image carrier of each solid image exposure element array in the axial direction and the rotation direction and at least one of the image forming positions, Correction means for correcting the image exposure states of the plurality of solid-state image exposure element arrays based on the detection result of the displacement detection means. Hereinafter, the detection means and the correction means will be described in detail.

Detection of Positional Displacement of LED Printhead Example 1-1 As shown in FIG. 1, the right end of the first LED printhead, both ends of the second LED printhead, and the third LED printhead At the left end of the head, a photo sensor 30 is disposed in a non-image area of the LED print head as a displacement detection unit for detecting a displacement of the photosensitive drum of the LED print head in the axial direction and / or the rotation direction. ing. The sensor 30 can detect which position of the light receiving surface is irradiated with the dot light, and a PSD sensor is generally known. The photo sensor 30 is mounted on the base 15 on which the LED print head 7 is mounted so as to be located between the LED print head 7 and the photosensitive drum 5 as shown in FIG. I have.

When the photo sensor 30 is directly disposed between the LED print head 7 and the photosensitive drum 5 as described above, the LED print head 7 is connected to the photosensitive drum 5 as shown in FIG. Since the focal length and the like of the selfoc lens 17 are set so as to form an image on the upper side, the LED element 28 exposed on the photo sensor 30
As shown in FIG. 9 (c), the dot is exposed by being defocused and divided into a plurality of dots. However, in this case, by using a photosensor 30 that can detect the exposure position, the position of the center of gravity is determined from the positions of the dots that have been divided and exposed, so that the photosensor 30 is exposed to light. It is possible to detect the dot position of the LED element 28 to be performed. FIG. 9D
As shown in FIG.
By providing 1 or the like and changing the focal length, dots of the LED element 28 can be formed on the photosensor 30. When this sensor is combined with a lens, it has been actually measured that the sensor output value with respect to the dot position change has a substantially linear relationship as shown in FIG.

Further, as shown in FIG. 10, a transparent prism 32 as a light guide member made of synthetic resin such as acrylic is disposed between the LED print head 7 and the photosensitive drum 5, The light beam 33 emitted from the LED element 28 is guided to the side of the LED print head 7, and the position of the dot exposed by the LED element 28 is determined by the photo sensor 30 arranged on the side of the LED print head 7. You may comprise so that it may detect. As shown in FIG. 10A, the prism 32 is attached to, for example, a selfoc lens 17 of an LED print head by bonding or the like. As shown in FIGS. 10B and 10C, the prism 32 has a flat rectangular shape and a substantially rectangular cross-sectional shape. A first reflecting surface 34 for reflecting light 33 introduced from the LED element 28 of the LED print head 7;
A second reflecting surface 35 that further reflects the light beam reflected by the reflecting surface 34 of the third surface, and a third reflecting surface 3 that reflects the light beam reflected by the second reflecting surface 35 and guides the light beam to the photosensor 30.
6 are provided. Further, a concave lens portion 37 which is concavely concave is formed at the incident portion of the prism 32. By extending the optical path length of the light 33 introduced from the LED element 28 of the LED print head 7, the LE is increased.
The dot-shaped light emitted from the D element 28 can be accurately imaged on the photosensor 30. If two concave lens portions 37 are formed at a predetermined distance from each other, two sensors 30 are used and each sensor 3
With 0, a position shift in the main scanning direction and a position shift in the sub-scanning direction can be detected.

In the electrostatic recording system, a voltage necessary for charging, which is a process before exposure by the LED print head, and development, which is a process after the exposure, are applied, so that the sensor output is easily affected by electric noise. Therefore, noise countermeasures such as shielding around the sensor and inserting a noise filter in the sensor circuit may be required. A detailed description of this will be omitted.

FIG. 35 shows the first LED print head 7 ₁
When is a flowchart showing a control example of the main scanning direction position of the second LED printhead 7 _2.

If the dot relative positions of the ends of the first LED print head 7 ₁ and the second LED print head 7 ₂ are appropriate in advance, the PSD sensor for the specific dot of the _second LED print head 7 ₂ , And the detection value b of the PSD sensor for the specific dot of the _first LED print head 71 are measured, and these are used as initial measurement values (step 101). Here, the specific dot refers to a dot at the end of the LED print head, such as the first dot or the last dot. If the PSD sensor is arranged almost in front of the dot, a change in dot position can be detected. The highest accuracy is obtained by directly measuring the dot positions at the junction of the LED print head, but they cannot be arranged because the sensor hinders image exposure.
Therefore, by measuring the change in the dot position in the vicinity of the connection, the change in the connection dot position is indirectly measured.

In order to control the connection position, first, a specific dot of each LED print head is turned on (step 102), and the detection values c and d of the PSD sensor are measured (step 103). It is determined whether or not these have changed with respect to the initial values a and b by calculating the following values (step 104). (Ab)-(cd) = e

If (lower limit of allowable range) <e <(upper limit of allowable range) (step 105), the specific dot is turned off (step 106), and the control is terminated. If e is out of the allowable range, the correction means described later is operated (step 10).
7).

This series of operations is effective, for example, immediately before or during image exposure.
The D print head may be operated in association with vibration or temperature change which causes the shift of the dot position at the connection.

Next, lighting control of a specific dot of the LED print head will be briefly described.

FIG. 36 shows an example in which two dots are lit in order to detect the positional deviation in the main scanning direction and the positional deviation in the sub-scanning direction by using two sensors in the overlapping portion of the LED print head. As shown in FIG.
A signal is generated such that a specific dot is turned on in accordance with a data shift block corresponding to an unused area of the D print head. The number of dots to be lit and the amount of light can be optimized according to the characteristics of the detection means. When a shift is detected during printing, print data is transferred to a print area of each print head, and when printing is not being performed, white data is transferred to that area.

Embodiment 2-1 In this embodiment 2-1, the displacement of the photosensitive drum of the LED print head in the axial direction (main scanning direction) and the rotation direction (sub scanning direction) is detected as follows. It is configured to be.

Detection of misregistration in the main scanning direction The first LED print head 7 and the second LED print head 7 are connected, for example, as shown in FIG. L) from left to right or from right to left
The ED elements are turned on one or more (one in the illustrated example). The total number of the LED elements 28 that are sequentially turned on one by one or a plurality of them is determined by the LED print head 7.
Is set to the number of dots corresponding to the maximum amount of deviation expected or the number of dots slightly larger than that. Also,
If the detection width of the photo sensor 30 is larger than the number of dots corresponding to the maximum deviation amount expected for the LED print head 7, the number of dots corresponding to the detection width of the photo sensor 30 is equal to or larger than that. It is set to a slightly larger number of dots.

Then, the LED print head 7
₁ (7 ₂ ) The position (order) of the lit LED element 28
When detects the receiving level of the photosensor 30 ₁ (30 ₂₎ at that time, the photosensor 30 ₁ (30 ₂₎
By comparing the detected value of the light receiving level with the previous measurement value (the initial adjustment initial value), the deviation amount of each LED print head 7 in the main scanning direction can be detected. In accordance with the result, as described later, the lighting pattern is shifted left and right based on the amount of displacement of each LED print head 7 or each LED print head 7 itself is moved left and right, so that each LED print head 7 is moved. Is corrected in the main scanning direction.

[0072] In the illustrated example, it has been described for detecting the displacement amount of the left end portion of the first LED print head ₇₁ of the right end portion and a second LED printhead, second
Right end portion and the third LED of the LED print head 7 ₂
The same applies to the case of detecting the displacement amount of the left end portion of the print head 7 _3.

[0073] the upper surface of the sub-scanning direction positional deviation detecting photosensor 30 _3, as shown in FIG. 11 (b), placing the slits 38 ₁ which is open in an oblique direction at a predetermined width, the deviation amount in the main scanning direction After the correction, similarly to the detection of the displacement in the main scanning direction, each LED print head 7 is, for example, set to a predetermined LED element 28 as shown in FIG.
(In the example shown, the LED element located third from the end)
From the left or right in order.
The LED print head 7
The position (order) of the lit LED element 28 and the light receiving level of the photo sensor 30 at that time are detected, and the detected value of the light receiving level of the photo sensor 30 is determined by the previous measurement value (the initial adjustment initial value). Value), each LE
The shift amount of the D print head 7 in the sub-scanning direction is detected.
Further, if the slit is formed in a triangular shape like 38 ₂ , a shift in the main scanning direction and the sub scanning direction can be detected by one sensor.

Embodiment 2-2 In Embodiment 2-2, the displacement of the photosensitive drum of the LED print head in the axial direction (main scanning direction) and the rotation direction (sub scanning direction) is detected as follows. It is configured to be.

Detection of misregistration in the main scanning direction The first, second, and third LED print heads 7 ₁ ,
For example, when the LED print heads 7 ₂ and 7 ₃ are capable of outputting a light amount of eight gradations, for example,
The LED print head ₇₁ and the second LED printhead 7 _2, as shown in FIG. 12, (in the illustrated example, five) plurality of right or left direction turns on the by gradation order of the LED elements 28 Let it. In the illustrated example, the color difference represents a gradation, and the lighter color indicates a state in which light emission of the LED element 28 is weak. At a position facing the LED print head 7, a photosensor 30 having a width capable of receiving light emitted from the LED element 28 having at least one gradation width and at most eight gradation widths or less is arranged. In this state, the first LED print head 7 ₁ and the second LED print head 7 ₂ are turned on collectively to turn on a plurality of 8-gradation LED elements, and the light emission amount of the LED element 28 at that time. the by receiving the photosensor 30 ₁ and 30 _2, detecting the amount of deviation of the photosensor 30 ₁ and 30 by the _second light receiving level first LED print head ₇₁ and the second LED printhead 7 ₂ Can be.

More specifically, in the illustrated example, the photo sensor 30 uses the L for eight LED print heads 7.
Has become capable of receiving light from ED element 28, if the first LED printhead 7 ₁ Re shifted to the left in the figure, the light receiving level of the photosensor 30 is sequentially reduced, first LED printhead 7 _{If 1} shifts to the right in the figure, the light receiving level of the photo sensor 30 increases sequentially. In addition,
When the deviation amount of the LED print head 7 is large, the detection range can be widened by increasing the number of the LED elements 28 that emit light at the same gradation within a range equal to or less than the width of the photosensor 30.

In this embodiment, since the LED elements 28 of each LED print head 7 need only be turned on collectively, the shift amount of the LED print head 7 can be detected in a short time.

[0078] the upper surface of the sub-scanning direction positional deviation detecting photosensor 30 _3, as shown in FIG. 12 (b), placing the slits 38 ₁ which is open in an oblique direction at a predetermined width, the deviation amount in the main scanning direction After the correction, similarly to the detection of the displacement in the scanning direction, each of the LED print heads 7 is shifted a plurality (five in the illustrated example) from the right or the left as shown in FIG. Adjustable LED element 2
8 collectively by lighting and by receiving the light emission amount of the LED element 28 at that time by the photo sensor 30 _3, L by the photosensor 30 ₃ of the light-receiving level
The shift amount of the ED print head 7 in the sub-scanning direction can be detected.

The above-mentioned LED print head 7 is shown in FIG.
Deviated in the sub-scanning direction (b), the since the slits 38 on the upper surface of the photosensor 30 ₃ are arranged, the photo sensor 3 also illuminates the same LED element 28
0 ₃ detected light changes. As the LED print head 7 shifts to the downstream side in the sub-scanning direction, the photo sensor 30
₃ of detected light is reduced, as shifted to the upstream side in the sub-scanning direction, the detection light amount of the photo sensor 30 ₃ is increased. In addition, the slit may be a triangle such as 38 _2.

Embodiment 2-3 In this embodiment 2-3, the displacement of the photosensitive drum of the LED print head in the axial direction (main scanning direction) and the rotation direction (sub scanning direction) is detected as follows. It is configured to be.

When the LED print head 7 is turned on,
On the surface of the photoreceptor drum 5, a right angle two
An image of the side triangle 40 is formed, and the right isosceles triangle 4
0's ₀The amount of change in the distance y between the hypotenuse 41 and the base 42 is
Detection by the sensor, the axial direction of the photosensitive drum 5
Of the right angled isosceles triangle
The amount of change in the position of the base 42 of 40 is detected by the photo sensor
By doing so, the positional deviation of the photosensitive drum 5 in the rotation direction is
The quantity can be determined.

The right-angled isosceles triangle 40 as described above is connected to the right end of the _first LED print head 71 and the second LE.
And D printhead 7 ₂ of both end portions, respectively formed in the third LED print head 7 left end of _3, the variation of the distance between the position of the oblique side 41 and bottom side 42 of the right-angled isosceles triangle 40, the photosensor , The amount of positional deviation of the photosensitive drum 5 in the axial direction and the rotation direction can be obtained.

Embodiment 2-4 In Embodiment 2-4, the displacement of the photosensitive drum of the LED print head in the axial direction (main scanning direction) is detected as follows.

Next, detection of the amount of displacement of the LED print head according to Embodiment 2-4 will be described.

The mounting position of the reflectance sensor 50 is, as shown in FIG. 15B, the downstream side of the developing device 8 when viewed from the side, and as shown in FIG. (in the illustrated example, 9 th LED from the right end) of the reference LED of the LED print head ₇₁ is mounted at a position capable of measuring the linear image formed by exposing the photosensitive drum 5.

First, the coarse adjustment of the LED print head in the main scanning direction will be described.

The purpose of this coarse adjustment is to find the LED of the _second LED print head 72 closest to the reference LED of the _first LED print head 71. In the illustrated example, in the second LED printhead 7 ₂ of the LED, the first LED print head ₇₁ of the reference LED
LED closest to (No.9), the second LED printhead 7 ₂ No. Is 7 or 8 LED of the second LED printhead 7 ₂ No. LE of 7 or 8
Finding D is the purpose of the sparse adjustment.

The sparse adjustment method is as follows.

Now, the first LED print head 7
₁ is fixed to the main body, and the second LED print head 7
₂ is supposed to be mounted movably along the main scanning direction. Here, LED of the first LED print head 7 on ₁ not lighted. Also, as shown in FIG. 14, the LEDs on the _second LED print head 72 are lit for a certain period of time, starting from the left, by several dots (two dots in the illustrated example). For example, No. ₂ On the second LED printhead 7 The LEDs of Nos. 3 and 4 were turned on for 1 second, and then No.
The LEDs 5 and 6 are turned on for one second.
Then, on the photosensitive drum 5, as shown in FIG.
A linear electrostatic latent image is formed along the rotation direction of the photosensitive drum 5, and the linear electrostatic latent image is developed by the developing device 8. A toner image in a shape of a circle is formed.

[0090] Thus, the toner image produced by lighting the LED print head 7 ₂ of the second is,
When the photosensitive drum 5 rotates, the output of the reflectance sensor 50 is measured at a timing when the photosensitive drum 5 reaches the position of the reflectance sensor 50. In FIG. 14, "Reflectance measurement point"
The circle described as "" indicates the measurement range. The measured value of the reflectance sensor 50 is, as is apparent from FIG.
The larger the number of toner images in the circle as the “reflectance measurement point”, the smaller the reflectance is measured. As a result, the measured value of the reflectance changes in the order of large reflectance (measured) → small (measured) → small (measured). It is a measurement that the measured value of the reflectance becomes a minimum value, and at this time, the second LED
Printhead 7 ₂ of the LED, No. 7 and 8 are lit.

Next, a method of fine adjustment will be described.

[0092] The purpose of this fine adjustment is to correct the first LED print head ₇₁ and the second 1-dot following the deviation of the LED print head 7 _2. By the coarse adjustment described above, the reference L of the _first LED print head 71 is set to L.
No. ED. I was able to find the nearest second LED printhead 7 ₂ of the LED to 9 LED of (No.7,8).

[0093] In the fine adjustment, by moving the second LED printhead 7 ₂ itself in the main scanning direction, the first LED print head ₇₁ of the reference LED in the main scanning direction (No.
9), a second LED printhead 7 ₂ LED (N
o. 7) The positions in the main scanning direction are matched.

In the above fine adjustment, first, the first LE
And D printhead 7 _first reference LED (No.9), turns on the second LED printhead 7 ₂ LED (No.7). Next, after a certain time, as shown in FIG.
(In the illustrated example, the length of 1/4 dot) second LED printhead 7 ₂ itself small amount in the right direction is moved by,
Again, the reference LED of the _first LED print head 71
(No. 9) and L of the _second LED print head 72
The ED (No. 7) is turned on. The above operation is repeated. Then, as shown in FIG. 37, a linear electrostatic latent image is formed on the photosensitive drum 5 along the rotation direction of the photosensitive drum 5, and the linear electrostatic latent image is developed. The toner image is developed by the device 8 and a linear toner image is formed along the rotation direction of the photosensitive drum 5.

[0095] Thus, the toner image produced by lighting the first LED print head ₇₁ and the second LED printhead 7 _2, by the rotation of the photosensitive drum 5, the reflectance sensor 50 At the timing of reaching the position, the output of the reflectance sensor 50 is measured. FIG.
In, the circle described as "reflectance measurement point",
The measurement range is shown. As a result, the measured value of the reflectance is minimized value is when the "Move 2", this time the first LED print head ₇₁ of the reference LED (No.
9), a second LED printhead 7 ₂ LED (N
o. The position of 7) matches.

In the above fine adjustment, the reflectance was measured.
At the end, the second LED print head 7_TwoMoves to the right
Too much. Therefore, the second LED print head
C7 _TwoTo the "movement 2" position,
Head 7_TwoThe camera itself is moved, and the correction operation ends.

Embodiment 2-5 In Embodiment 2-5, the positional deviation of the photosensitive drum of the LED print head in the axial direction (main scanning direction) is detected as follows.

Next, detection of the amount of displacement of the LED print head according to Embodiment 2-5 will be described.

First, the purpose of the fine adjustment performed here will be described.

[0100] The purpose of this fine adjustment is to correct the first LED print head ₇₁ and the second 1-dot following the deviation of the LED print head 7 _2. Example 2-
The coarse adjustment of 4, an LED serving as the first LED print head ₇₁ in the reference No. Nearest second LED printhead 7 ₂ of the LED to 9 LED of (No.7,
8) was found.

[0102] In the fine adjustment, by moving the second LED printhead 7 ₂ itself in the main scanning direction, the first LED print head ₇₁ of the reference LED in the main scanning direction (No.
9), a second LED printhead 7 ₂ LED (N
o. 7) The positions in the main scanning direction are matched.

In the fine adjustment, first, the first LE
Turns on the D printhead 7 _first reference LED (No.9), the ₂ second LED print head 7 to light the LED other than LED (No.7) of interest. next,
After a certain time, as shown in FIG. 16, the small amount (shown example the second LED printhead 7 ₂ itself to the right, 1 /
(The length of 4 dots) and again the first LED
Printhead 7 _first reference LED to (No.9) is lit, the second LED printhead 7 ₂ of the LED (No.
7) Turn on the other LEDs. The above operation is repeated. Then, an electrostatic latent image is formed on the photosensitive drum 5 as shown in FIG.
And a toner image is formed.

[0103] Thus, the toner image produced by lighting the first LED print head ₇₁ and the second LED printhead 7 _2, by the rotation of the photosensitive drum 5, the reflectance sensor 50 At the timing of reaching the position, the output of the reflectance sensor 50 is measured. FIG.
Indicates the measurement range. As a result, the measured value of the reflectance reaches the maximum value at the time of “movement 2”, and at this time, the reference L of the _first LED print head 71 is changed.
ED (No. 9) and the second LED print head 7 ₂
LED (No. 7) coincides with each other.

In the fine adjustment, the reflectance was measured.
At the end, the second LED print head 7_TwoMoves to the right
Too much. Therefore, the second LED print head
C7 _TwoTo the "movement 2" position,
Head 7_TwoThe camera itself is moved, and the correction operation ends.

Embodiment 2-6 In this embodiment 2-6, the displacement of the focal position of the LED print head is detected as follows.

[0106] In the embodiment 2-6, a first LED printhead ₇₁ of the right end portion, a second LED printhead 7 ₂ at both ends, in the third left portion of the LED print head 7 _3, As shown in FIG. 17, a halftone dot image having a predetermined density or a linear image having a predetermined line width as shown in FIG. 18 is exposed on the photosensitive drum 5 to develop this electrostatic latent image. Thus, a toner image is formed.

The density sensor 50 detects the density or the line width of the halftone dot image 52 formed on the photosensitive drum 5 or the linear image 53 having the predetermined line width.

If the focal positions of the first, second, and third LED print heads 7 ₁ , 7 ₂ , and 7 ₃ are at the predetermined positions, the halftone dot image 52 having the predetermined density can be obtained by, for example, FIG.
As shown in FIG. 7A, each halftone dot is clearly formed, and the density of the entire halftone dot image 52 is reduced. In contrast, LED
If the focus positions of the print heads 7 ₁ , 7 ₂ , and 7 ₃ are shifted, the halftone dot image 52 having the predetermined density is, for example, shown in FIG.
As shown in (b), each halftone dot is formed in a blurred and spread state, and the density of the entire halftone image 52 becomes high. Therefore, by detecting the density of the halftone image 52 having the predetermined density by the density sensor 50, the first, second, and third dots are obtained.
It is possible to detect whether or not the focal positions of the LED print heads 7 ₁ , 7 ₂ , 7 ₃ are in a predetermined position. The same applies to the linear image 53 having a predetermined line width as shown in FIGS.

Embodiment 2-7 In this embodiment 2-7, the displacement of the LED print head is detected as follows.

In the embodiment 2-7, as shown in FIG. 19, the first, second, and third LED print heads 7 ₁ , 7
_The base 15 to which ₂ and 7 ₃ are attached is configured to be rotatable around a fulcrum 61 by an arm 60 attached to the base 15, and the first, second, and third LEDs are The base 15 to which the print heads 7 ₁ , 7 ₂ , and 7 ₃ are attached is configured to be rotatable clockwise by driving means including a stepping motor and gears (not shown). The first, second, and third LED print heads 7 ₁ , 7 ₂ , and 7 ₃ are attached to the base 15 to which the first, second, and third LED print heads are rotated clockwise by a predetermined angle. the third LED print head 7 _1, 7 ₃ position opposed to, is attached in a state in which photosensor 61 is fixed to the frame 62. As the photosensor 61, a position detection sensor capable of one-dimensional or two-dimensional position detection is used. This one
Examples of the two-dimensional or two-dimensional position detection sensor 61 include, for example, PSD (Position Sensitivity).
e Detector), a linear CCD, or the like.

In this embodiment, the first, second, and
3 LED print head 7₁, 7 _Two, 7_ThreeIs attached
Of the base 15 is rotated clockwise by a predetermined angle
The first and third LED print heads 7₁, 7_ThreeTo
The photo sensor 6 is opposed to the photo sensor 61.
1, the first and third LED print heads 7 ₁,
7_ThreeDetect the position of. Next, the first, second, and third LEs
D print head 7 ₁, 7_Two, 7_ThreeBase with attached
The board 15 is further rotated clockwise by a predetermined angle.
And the second LED print head 7_TwoThe photo sensor
61 and the photo sensor 61
2 LED print head 7_TwoDetect the position of. That
The first, second, and third LED print heads
7₁, 7_Two, 7_ThreeTurn the base 15 with
The second LED print
Good 7_TwoCan be detected in the sub-scanning direction.
However, the first, second, and third LED print heads
7₁, 7_Two, 7_ThreeRotational accuracy of the base 15 on which is mounted
The second LED print head 7_TwoSub-scanning method
Since the detection accuracy of the direction position is determined, the second LED print
Head 7_TwoEtc. can be positioned with high accuracy.
For example, as a driving means, a stepping motor or an
Servo motors using encoders with high reduction ratios
It is desirable to use

Example 2-7-2 In Example 2-7-2, 1 was used as the photosensor.
Instead of a position detection sensor capable of detecting a two-dimensional or two-dimensional position, as shown in FIG. 20, two photo sensors 65 and 6 provided with horizontal slits 63 and 64 are provided.
6 and one photosensor 68 provided with a diagonal slit 67 are used so that a total of three photosensors are used.

The base 1 on which the first, second, and third LED print heads 7 ₁ , 7 ₂ , and 7 ₃ are mounted.
5 is gradually rotated clockwise, so that the first
21 from the second photosensors 65 and 66, FIG.
A signal as shown in (a) is output, and by comparing this output signal with a predetermined threshold value, the rising intervals l ₁ and l ₂ of two pulses are obtained as shown in FIG. By dividing the sum (l ₁ + l ₂ ) of these _two by two, the first and third LED print heads are:
It is possible to detect the distance between the ₂ second LED printhead 7. Further, the first, second, and third LED print heads 7 ₁ , 7 are provided by the third photo sensor 68.
It is possible to detect the position of the _2, 7 ₃ in the main scanning direction.

In this case, the photo sensors 65, 66, 6
As long as it can detect light, many elements such as a photodiode and a phototransistor 8 can be used. In particular, a PIN photodiode is one of promising elements.

Configuration of Correction Means Embodiment 3-1 In the embodiment 3-1 as shown in FIG. 1 and FIG.
The first and third LED print heads 7 ₁ and 7 ₃ are provided at both ends of the first and third LED print heads 7 ₁ and 7 3.
_As an actuator for moving ₃ in the main scanning direction, a thin wire-shaped shape memory alloy 70 in which a contracted state is stored is attached. As the shape memory alloy 70, for example, a biometal fiber (trade name) manufactured by Toki Corporation can be used. The thin wire-shaped shape memory alloy 70 is shown in FIG.
As shown in FIG. 2, for example, one end is directly attached to the end of the LED print head 7 by means such as screwing. The other end of the shape memory alloy 70 is LE
The D print head 7 is also attached to the protrusion 71 erected on the base 15 to which the D print head 7 is attached by means such as screwing. The shape memory alloy 70 is the same as that shown in FIG.
As shown in FIG. 3, both ends may be fixed by caulking with hollow pins made of a conductive material. When the base is made of metal (conductor), it is necessary to interpose an insulator as shown in the figure.

[0116] Also, the first and third LED print head 7 _1, 7 _3, as shown in FIG. 22 (b), the rear surface of the first and third LED print head 7 _1, 7 ₃ The upright pin 73 is fitted in a long hole 74 formed in the base 15 on which the LED print head 7 is mounted, so that the pin 73 is movable in the main scanning direction. Further, the first and third LED print heads 7 ₁ ,
7 ₃ at the distal end of the erected pin 73 on the back surface, the L
Base 1 on which ED print heads 7 ₁ and 7 ₃ are attached
5, the tip of a leaf spring 75 screwed is engaged,
The back surface of the LED print head 7 is pressed against the substrate with a predetermined force by a leaf spring 75. If gravity is used, this leaf spring can be omitted. The leaf spring 75 is provided at its distal end with a groove in which the distal end of the pin 73 engages, so that the pin 73 can move freely. As a result, as described below, the LED print head 7 has a shape memory alloy 70 as an actuator.
Is movable in the main scanning direction, and the position after the movement can be held.

On the other hand, the second LED print head 7
Approximately _2, as shown in FIG. 22 (a), has a rotatable one end as a fulcrum, to the free tip second LED printhead 7 ₂ of pivoting, with grooves 76a A disc-shaped cam 76 is engaged. A thin wire-shaped shape memory alloy 77 is attached to both sides of the rotation center 78 of the substantially disk-shaped cam 76, and the cam 76 is driven to rotate by expansion and contraction of the shape memory alloy 77. , the second end of the LED print head 7 ₂ rotates, has a skew can be corrected.

Further, a DC power supply 80 is connected to both ends of the shape memory alloys 70 and 77 via a switch 79, and the shape memory alloys 70 and 77 can be energized by the DC power supply for a predetermined time. I have. The shape memory alloys 70 and 77 are heated by the direct current power supply 80 to restore the contracted state stored when the temperature exceeds the transformation point temperature. The amount of restoration cannot be controlled due to fluctuations due to various factors, but usually contracts gradually within about 0.1 second. Therefore, while energizing while observing the movement of the LED print head with the PSD sensor 30, etc.,
The power supply is cut off when the target position is reached. The shape memory alloy stretches again, but does not push back the pulled LED printhead, thus achieving the target. The energization is not continuous, for example, 1 ms ON, 1 ms OF
When a pulse-like current is applied as in F, control of the contraction speed is easy.

[0119] Thus, the first and second 3 LED print head 7 _1, 7 _3, by energizing the direct current power source on one side of the shape memory alloy 70, the LED print head 7 _1, 7 ₃ predetermined amount It can be moved along the main scanning direction. In addition, the first and third
The LED print heads 7 ₁ , 7 ₃ move the other shape memory alloy 70 by a DC power supply to move the LED print heads 7 ₁ , 7 ₃ to the opposite side in the main scanning direction by a predetermined amount. It is also possible.

On the other hand, the second LED print head 7
_{2. When} a shape power alloy 77 on one side is energized by a DC power supply 80, the cam 76 is rotated by a desired angle, and one end of the _second LED print head 72 engaged with the 76 cam is rotated. And the skew can be corrected.

In the embodiment 3-1 described above, the position of the LED print head 7 can be accurately corrected with a simple configuration by using the thin wire-shaped shape memory alloys 70 and 77. The actuator for moving the LED print head 7 in the main scanning direction or the sub-scanning direction may, of course, be constituted by a mechanical component comprising a combination of a stepping motor, a gear, a clutch and the like. Further, the LED print head may be moved in the main scanning direction or the sub scanning direction by using a piezo element or the like.

In the embodiment 3-1 described above, the moving means is connected to one end of the solid-state image exposure element array and contracted by energization and connected to the other end. You may comprise so that it may consist of a tension spring.

In this embodiment, as shown in FIG.
One end of the ED print head 7 has a shape memory alloy 70
And a power supply and switch control circuit. LE
A tension spring is attached to the other end of the D print head 7 and pulled. By applying a pulse to the shape memory alloy 70 by controlling the switch and changing the ON / OFF duty ratio, the amount of current can be adjusted. Therefore, if the amount of energization is controlled while monitoring the dot light position with the sensor 30, the contraction amount of the shape memory alloy 70 is properly maintained, that is, the dot light position can be properly maintained. The control means may be a method of directly changing the energization amount instead of a method of changing the energization duty ratio.

In such a case, there is an effect that the control is simple because the shape memory alloy 70 is located at one place.

As means for moving the LED print head 7 to both sides, as shown in FIG.
0 may be sagged and fixed. Then, the third embodiment is described.
As described in -1, when the position of the LED print head 7 is shifted, both or one of the shape memory alloys 70 may be configured to be energized and pulled.

In this case, when the image forming apparatus is not used or when there is no change in the dot position, the energization is stopped, so that it is not necessary to always energize the shape memory alloy, and power saving can be achieved. Therefore, the load can be released, and the durability can be improved.

[0127] In Example 3-2 This example 3-2, the first, second, is configured to correct the positional deviation of the third LED print head _71, 7 _2, 7 ₃ in the sub-scanning direction ing.

Normally, the positional deviation of the first, second, and third LED print heads 7 ₁ , 7 ₂ , and 7 _{3 in} the sub-scanning direction is caused by the LED print heads 7 ₁ , 7 ₂ , and 7 ₃ . When data is transferred, the correction is performed by transferring the image data through a delay circuit. However, when correcting the positional deviation in the sub-scanning direction through the delay circuit, 1 is used.
It can only be corrected in line units, and cannot correct positional deviations of one line or less. Therefore, the first, second, and third LED print heads 7 ₁ , 7 ₂ , 7 ₃
As shown in FIG. 24, when the positions are shifted from each other in the sub-scanning direction and the position shift includes a position shift of one line or less, the first and second positions are shifted as shown in FIG. 2, at the 3 LED print head _71, the 7 _2, 7 ₃ at the joint, misalignment of less than one line occurs.

At this time, as shown in FIG. 25A, the first, second, and third LED print heads 7 ₁ , 7 ₂ , and 7 ₃ correspond to four blocks of each LED print head. The strobe signal STRB is output in the order of 1 to 4, and the first, second, and third LED print heads 7 ₁ , 7
_2, 7 _3, as shown in FIG. 25 (b), image exposure is performed by dividing into four each LED print head. Therefore, the first, second, and third LED print heads 7 ₁ ,
7 _2, 7 ₃ at the joint, when the positional displacement of less than one line is present, as shown in FIG. 25 (b), the first L
A right end portion of the ED printhead _71, as in the second LED printhead 7 ₂ at the left end, deviation in the sub-scanning direction is increased, for example, when recording an image of one straight line, the first LED print heads ₇₁ and will level difference occurs in the second joint of the LED print head 7 _2, there is a case where the step of the joint is to the extent that is recognized visually.

Therefore, in this embodiment, the first, second, and
3 LED print head 7₁, 7 _Two, 7_ThreeSeam
When there is a displacement of one line or less, FIG.
As shown in FIG. 5 (c), each LED print head 7₁,
7_Two, 7_ThreeSo that the step does not become large at the joint,
Each LED print head 7₁, 7_Two, 7_ThreeBlock of
The order in which the lights are lit is changed as appropriate.
You.

[0131] In the illustrated embodiment, as shown in FIG. 25 (c), the first LED print head ₇₁ is assigned a strobe signal STRB for each block B1~4 in 4,3,2,1, the the second LED printhead 7 ₂ blocks, a strobe signal STRB in order of 3,4,2,1, the third LED print head 7 ₃ blocks,
The strobe signal STRB is assigned to 1, 2, 3, 4 and output respectively, and the first LED print head 7 ₁
Almost a right end portion, together with eliminating the step of the second LED printhead 7 ₂ at the left end, and a second LED printhead 7 ₂ at the left end, the third step of the right end portion of the LED print head 7 ₃ of It is designed to be lost.

Embodiment 3-3 Embodiment 3-3 is configured to correct the positional deviation of the first, second, and third LED print heads in the main scanning direction.

That is, in Embodiment 3-3, the first,
Second, when the third LED print head _71, 7 _2, 7 ₃ position deviation in the main scanning direction is large, FIG. 26 (a)
As shown in FIG.
The D element 28 lit brighter than the other elements, first, when the second, third LED print head _71, 7 _2, 7 is small interval in the main scanning direction _3, FIG. 26 (b) As shown in FIG. 5, the adjacent LED elements 28 of the LED print heads 7 ₁ , 7 ₂ , and 7 ₃ are configured to be lit darker than the other elements, and as a result, an image formed on the photosensitive drum 5 is formed. It is configured such that the seam of is not visually noticeable.

In this embodiment, the first, second, and third LEs
The LED print heads 7 ₁ , 7 ₂ , 7 are arranged in accordance with the amount of displacement of the D print heads 7 ₁ , 7 ₂ , 7 _{3 in} the main scanning direction.
It is only necessary to control the brightness of the _third LED element 28, and the configuration is simple.

Embodiment 3-4 In Embodiment 3-4, the first, second, and third LED print heads are configured to correct positional deviation in the main scanning direction.

That is, in Embodiment 3-4, the first,
When the overlap of the second and third LED print heads 7 ₁ , 7 ₂ , and 7 _{3 in} the main scanning direction is large, FIG.
As shown in (a), the second L is obtained from the XY image data.
Transfers the image data to the ED printhead 7 _2, and is configured to transfer the image data to the third LED print head 7 ₃ from the image data of the X-Y + X-Y2.

Also, when the first, second, and third LED print heads 7 ₁ , 7 ₂ , and 7 ₃ have a small overlap in the main scanning direction, similarly, as shown in FIG.
From the image data of −Z, the second LED print head 7 ₂
Image data transfers the, is configured to transfer the image data from the image data of the X-Z + X-Z2 to the third LED print head 7 _3.

The advantage of Embodiment 3-4 is that even if the positional relationship of dots changes by one dot or more, it is possible to prevent the positional relationship of joints from being reversed. In other words, by correcting the area for transferring the image data in this manner, even if the area fluctuates by one dot or more, the image data is transferred to the next LED print head 7, whereby the positional relationship of the joint is reversed. Can be prevented. If a correction involving correction of one dot or less (for example, 5.5 dots) is required, the third embodiment is used.
By combining the third embodiment with the third embodiment, the correction can be performed.

Further, in Embodiment 3-4, FIG.
As shown in (a), each LED print head may be provided with a reference position, and the data transfer position may be changed in accordance with the dot position corresponding to the reference position. In this case, the reference position of each LED print head is set to, for example, the end (the first and third LEs) of each LED print head.
D printhead 7 _1, 7 _3, the end portion of the center side, a second LED printhead 7 _2, and 4 th dot from both ends). Then, the shift amount detection, there is no shift in the LED print head, if it is placed at the reference position, the first LED print head _71, from the right end 5
It lights up to the dot, and the second LED print head 7 ₂
Starts lighting from the fifth dot from the left end. The relation between the second LED print head 7, _second and third LED print head 7 ₃ is similar.

[0140] Next, when the reference dot position of the LED print head is shifted, as shown in FIG. 39 (b), the first reference dot position of the LED print head ₇₁ is, Y dots from the right end to the left position, the reference dot position of the second LED printhead 7 _2, when shifted at positions of the Y2 dots from the right end to the left side, X-Y dot position second from the data of the LED print head 7 ₂ to the image data To transfer. Also, the second LED print head 7
₂ starts lighting from fifth dot from the left end, is turned from the right to Y2 + 1-th dot. Furthermore, the third LE
The D print head 7 _3, to forward the image data from the position of X-Y + X-4- Y2 dots. This third LE
D print head 7 ₃ starts lighting from fifth dot from the left end, it is turned until the data end position.

Since the writing start position of the _first LED print head 71 changes depending on the image size, side registration adjustment, etc., the switching of the data transfer position shifts according to the amount.

Embodiment 3-5 In this embodiment 3-5, when the photosensitive drum 5 is eccentric or the like and the moving speed of the surface of the photosensitive drum 5 varies, the movement of the surface of the photosensitive drum 5 is changed. The correction is performed so that the speed variation does not appear on the image.

If there is a variation in the moving speed of the surface of the photosensitive drum 5, if the positions of the first LED print head and the second LED print head in the sub-scanning direction are simply corrected, as shown in FIG. In some cases, a step may occur in a linear image.

Therefore, in the embodiment 3-5, as shown in FIG. 29, the surface speed of the photosensitive drum 5 is detected by the surface speed detecting means 85, and the exposure timing is adjusted according to the surface of the photosensitive drum 5. By the control unit 86, the second L
The exposure timing and the like of the ED print head are controlled to prevent a step from occurring in a linear image.

At this time, without using the surface speed detecting means 85, as shown in FIG. 30, a linear image is formed on the surface of the photosensitive drum 5 at a constant exposure timing along the main scanning direction. Then, this linear image is detected by a photo sensor or the like, and the variation in the interval between the linear images is determined for one rotation of the photosensitive drum 5, and this is stored in a correction table as a correction value. The exposure timing in the sub-scanning direction of the second LED print head or the like may be corrected based on the table.

Embodiment 3-6 In this embodiment 3-6, when the photosensitive drum 5 is eccentric or the like and the moving speed of the surface of the photosensitive drum 5 varies, the movement of the surface of the photosensitive drum 5 is changed. The correction is performed so that the speed variation does not appear on the image.

[0147] When there is variation in the moving speed of the photosensitive drum 5 surface, ₁ and the first LED print head 7, by merely correcting the position of the second LED printhead 7 ₂ in the sub-scanning direction, FIG. 29 As shown in (1), a step may occur in a linear image.

Therefore, in this embodiment 3-6, as shown in FIG. 31, the first and third LED print heads 7 ₁ , 7 are used by using an actuator 90.
_3, the distance between the second LED printhead 7 ₂ in the sub-scanning direction, changing in synchronization with the rotation of the photosensitive drum _5,
It is configured to prevent a step from occurring in a linear image.

Embodiment 3-7 In this embodiment 3-7, as shown in FIG. 32 (a), the focal position is shifted between the first LED print head and the second LED print head and the like. Figure 3
2 (b) As shown in the order to prevent the variation in gray in the image along the sub-scanning direction is generated, as shown in FIG. 32 (c), the first LED print head ₇₁ and the second based LED print head 7 ₂ or the like is attached 15
And is inclined by a predetermined angle, and _one first LED print head 7, by correcting the positional deviation of the focal position, such as ₂ second LED printhead 7, the shading in the image along the sub-scanning direction This is configured to prevent the occurrence of variation.

Embodiment 3-8 In this embodiment 3-8, as shown in FIG.
Such as the printhead _71, 7 _2, 7 ₃ of the surface (heat sink) side, a temperature sensor (thermistor) 91-9
3 attached to each of these LED print heads 7 ₁ ,
7 _2, 7 ₃ temperature measured. Then, each of the LEs
By previously collected back data indicating the D printhead 7 _1, 7 _2, 7 ₃ temperature and the relationship of the dot position change, which is constituted to be able to determine the adjustment amount of the dot positions.

Embodiment 4 FIGS. 40 and 41 show Embodiment 4 of the present invention. The same portions as those of the above embodiment are denoted by the same reference numerals. The linear solid-state image exposure element arrays are arranged along the axial direction of the image carrier so that at least the positions of the adjacent solid-state image exposure element arrays in the rotation direction of the image carrier are different. In the image forming apparatus for forming an image by dividing the entire image width of the image carrier by the image exposure element array and exposing the image, in the axial direction and the rotation direction of the image carrier of each solid image exposure element array. It is configured to include a correction unit for correcting at least one positional deviation of the position and the focal position, and an input unit for inputting a correction amount of the correction unit.

Here, as the input means, for example,
Although a key of a control panel provided in the image forming apparatus can be used, a dip switch or the like provided for adjustment by a service engineer or the like may be used.

Next, a method of detecting and correcting (adjusting) the amount of displacement of the LED print head according to the third embodiment will be described. The detection and correction (adjustment) of the displacement amount of the LED print head is mainly performed at the time of finishing the assembly of the image forming apparatus or at the time of installing the machine.

[0154] The purpose of this adjustment is to correct the first LED print head ₇₁ and the second 1-dot following the deviation of the LED print head 7 _2. Basically, similarly to the fine adjustment of Examples 1-5, by moving the second LED printhead 7 ₂ itself in the main scanning direction, the first LED print head ₇₁ of the reference in the main scanning direction LED (N
o. 9), a second LED printhead 7 ₂ of the LED
The position of (No. 7) in the main scanning direction is matched.

In the above adjustment, first, the first LED
Turns on the print head ₇₁ of the reference LED (No.9), the second LED printhead 7 _2, L of interest
LEDs other than ED (No. 7) are turned on. Then, after a certain time, as shown in FIG. 40, the small amount (shown example the second LED printhead 7 ₂ itself to the right, 1/4
The length of the dots) is moved by, again, the first LED print head ₇₁ of the reference LED to (No.9) is lit, the second LED printhead 7 ₂ of the LED (No.
7) Turn on the other LEDs. The above operation is repeated. Then, an electrostatic latent image is formed on the photosensitive drum 5, as shown in FIG.
Is developed and transferred and fixed as a toner image on paper. At this time, the toner image on the paper is as shown in FIG.

The operation of detecting the amount of displacement of the LED print head as described above is automatically performed by the CPU of the machine. However, when assembling or installing the machine, a worker or a service engineer or the like as shown in FIG. As shown, the toner image on the paper is visually observed, and at the fifth position from the top, the reference LED of the _first LED print head 71 is displayed.
(No. 9) and L of the _second LED print head 72
It can be seen that the positions of ED (No. 7) match.
Then, at the time of installation of the assembly work and machine workers and service engineer or the like, by operating the keys of the control panel image forming apparatus as an input means is provided, a second LED printhead 7 ₂ above the corresponding position, by moving the second LED printhead 7 ₂ itself, adjustment operation is completed.

[0157]

As described above, according to the present invention,
By connecting a plurality of linear solid-state image exposure element arrays, the entire image width of a wide image carrier is divided and image exposure is performed, but even if a configuration is adopted in which a plurality of linear solid-state image exposure elements are exposed due to thermal expansion or the like. Due to the displacement of the linear solid-state image exposure element array of the book, the image has uneven lines, overlap, steps,
An image forming apparatus capable of preventing the occurrence of density unevenness or the like can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view showing an image exposure section of an image forming apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram showing an image forming apparatus according to Embodiment 1 of the present invention.

3 (a) and 3 (b) show Embodiment 1 of the present invention.
FIG. 3 is an explanatory diagram illustrating an image exposure unit of the image forming apparatus according to the first embodiment.

FIGS. 4A and 4B show Embodiment 1 of the present invention.
FIG. 2 is a plan view and a front view showing the LED print head according to the first embodiment.

FIG. 5 is a cross section showing an LED print head.

FIG. 6 is a block diagram showing a driving circuit of the LED print head.

FIG. 7 is a timing chart showing a driving state of the LED print head.

FIG. 8 is a timing chart showing a driving state of the LED print head.

FIGS. 9A to 9D show Embodiment 1 of the present invention.
FIG. 3 is an explanatory diagram illustrating a misalignment detection unit of the image forming apparatus according to the first embodiment.

10 (a) to 10 (c) show Example 1 of the present invention.
FIG. 2 is a configuration diagram illustrating a displacement detection unit of the image forming apparatus according to the first embodiment.

11 (a) and 11 (b) show Embodiment 2 of the present invention.
FIG. 4 is an explanatory diagram illustrating a position shift detection detecting unit of the image forming apparatus according to FIG.

FIGS. 12A and 12B show Embodiment 2 of the present invention.
FIG. 4 is an explanatory diagram illustrating a position shift detection and detection unit of the image forming apparatus according to −2.

FIG. 13 is an explanatory diagram showing a misregistration detecting unit of the image forming apparatus according to Embodiment 2-3 of the present invention.

FIG. 14 is an explanatory diagram showing a displacement detection unit of the image forming apparatus according to Embodiment 2-4 of the present invention;

FIGS. 15A and 15B show a second embodiment of the present invention.
FIG. 4 is a configuration diagram illustrating a misregistration detection detection unit of the image forming apparatus according to the fourth embodiment.

FIG. 16 is an explanatory diagram showing a displacement detection unit of the image forming apparatus according to Embodiment 2-5 of the present invention;

17 (a) and (b) show Embodiment 2 of the present invention.
FIG. 9 is an explanatory diagram illustrating a position shift detection unit of the image forming apparatus according to −6.

FIGS. 18A and 18B show a second embodiment of the present invention.
FIG. 13 is an explanatory diagram illustrating a displacement detection unit of an image forming apparatus according to a modification example of −6.

FIG. 19 is an explanatory diagram showing a displacement detection unit of the image forming apparatus according to Embodiment 2-7 of the present invention;

FIG. 20 is an explanatory diagram showing a displacement detection unit of the image forming apparatus according to a modification of the embodiment 2-7 of the present invention.

FIG. 21 is an explanatory diagram showing a displacement detection unit of an image forming apparatus according to a modification of the embodiment 2-7 of the present invention.

22 (a) and 22 (b) show Embodiment 3 of the present invention.
1A is a plan view and FIG.

FIG. 23 shows a configuration of a correction unit of the image forming apparatus according to Embodiment 3-1 of the present invention.

24 (a) and (b) show Embodiment 3 of the present invention.
FIG. 4 is an explanatory diagram illustrating correction units of the image forming apparatus according to −2.

FIGS. 25 (a) to 25 (c) are explanatory diagrams respectively showing correction means of the image forming apparatus according to Embodiment 3-2 of the present invention.

26 (a) and 26 (b) show Embodiment 3 of the present invention.
FIG. 3 is an explanatory diagram illustrating correction units of the image forming apparatus according to the third embodiment.

27 (a) and 27 (b) show Embodiment 3 of the present invention.
4 is an explanatory diagram illustrating a correction unit of the image forming apparatus according to the fourth embodiment.

28 (a) and (b) show Embodiment 3 of the present invention.
FIG. 9 is an explanatory diagram illustrating a state before correction by a correction unit of the image forming apparatus according to −5.

FIG. 29 is an explanatory diagram showing a correction unit of the image forming apparatus according to Embodiment 3-5 of the present invention.

FIG. 30 is an explanatory diagram showing a correction method by a correction unit of the image forming apparatus according to Embodiment 3-5 of the present invention.

FIG. 31 is an explanatory diagram showing a correction method by a correction unit of the image forming apparatus according to Embodiment 3-6 of the present invention.

FIGS. 32 (a) to 32 (c) are explanatory diagrams respectively showing correction means of the image forming apparatus according to Embodiment 3-7 of the present invention.

FIG. 33 is a configuration diagram illustrating a correction unit of an image forming apparatus according to Embodiment 3-8 of the present invention;

FIG. 34 is a graph showing a relationship between a sensor output value and a dot position.

FIG. 35 is a flowchart showing a control operation.

FIG. 36 is a timing chart showing signals for correction.

FIG. 37 is an explanatory diagram showing a displacement detecting unit of the image forming apparatus according to Embodiment 2-5 of the present invention;

FIG. 38 is a configuration diagram showing another example of the correction means.

FIGS. 39 (a) and (b) are explanatory diagrams respectively showing the correction states of the LED print head.

FIG. 40 is an explanatory diagram illustrating a position shift detection method of the image forming apparatus according to the fourth embodiment of the present invention.

FIG. 41 is an explanatory diagram illustrating an image formed by the position shift detecting method of the image forming apparatus according to the fourth embodiment of the present invention.

[Explanation of symbols]

7 ₁ , 7 ₂ , 7 ₃ : LED print head (solid-state image exposure element array), 15: substrate, 30: photo sensor (position shift detecting means), 70, 77: shape memory alloy (correcting means).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 21/14 (72) Inventor Masato Koyama 3-7-1, Funai, Iwatsuki-shi, Saitama Fujize Rocks, Ltd. Within (72) Inventor Koji Tsutsumi 3-7-1, Fuuchi, Iwatsuki-shi, Saitama Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Naoki Honma 3-7-1, Fuuchi, Iwatsuki City, Saitama Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Nobuo Murata 3-7-1 Fuchu, Iwatsuki-shi, Saitama F-term in Fuji Xerox Co., Ltd. (reference) 2C162 AE04 AE14 AE21 AE28 AE47 AE57 AE58 AF07 AF13 AF19 AF27 AF82 FA04 FA16 FA17 FA45 2H027 DA23 DE02 DE09 DE10 EA18 EC03 ED04 ED06 ZA07 2H076 AB42 AB60 AB67

Claims (26)

[Claims] 1. A plurality of linear solid-state image exposure element arrays are arranged along the axial direction of an image carrier such that at least adjacent solid-state image exposure element arrays have different positions in the rotation direction of the image carrier. An image forming apparatus that forms an image by dividing the entire image width of the image carrier by the plurality of solid-state image exposure element arrays and exposing the image; Displacement detection means for detecting at least one of a displacement in an axial direction and a rotational direction, and a focus position, and image exposure of the plurality of solid-state image exposure element arrays based on a detection result of the displacement detection means. An image forming apparatus comprising: a correction unit configured to correct a state. 2. The solid-state image exposure device according to claim 1, wherein the position error detection unit causes a predetermined number of solid-state image exposure devices located near at least one end of each solid-state image exposure device array to emit light, and detects a light emission position of the solid-state image exposure device. 2. The image forming apparatus according to claim 1, wherein the position of the solid-state image exposure element array is detected. 3. The solid-state image sensing device according to claim 1, wherein said solid-state image sensing device emits light from a solid-state image sensing device located near at least one end of each solid-state image sensing device array to form an electrostatic latent image on a surface of said image carrier. 2. The image forming apparatus according to claim 1, wherein the electrostatic latent image is developed to form a toner image, and a position of the solid image exposure element array is detected by detecting a position of the toner image. apparatus. 4. The apparatus according to claim 1, wherein the position shift detecting means includes a light receiving element disposed directly between each solid-state image exposing element array and the image carrier, or a light guiding element for guiding light from each solid-state image exposing element array to the light receiving element. The image forming apparatus according to claim 1, wherein an optical member is disposed, and the light receiving element detects a position shift of the solid-state image exposure element array. 5. The solid-state image sensing device according to claim 1, wherein the position shift detecting unit is configured to move the solid-state image exposing elements located near at least one end of each solid-state image exposing element array by a predetermined number of solid-state image exposing elements in the axial direction of the image carrier. The solid-state image exposure element array is sequentially turned on, and the amount of light emitted from the solid-state image exposure element is detected by a light-receiving element, thereby detecting a positional shift along the axial direction of the image carrier of the solid-state image exposure element array. The image forming apparatus according to claim 1. 6. The solid-state image exposure device according to claim 1, wherein said solid-state image exposure device is positioned at least in the vicinity of at least one end of each of said solid-state image exposure device arrays by a predetermined number in the axial direction of said image carrier. The solid-state image exposure element array is sequentially lit, and the amount of light emitted by the solid-state image exposure element is detected by a light-receiving element through a slit inclined along the rotation direction of the image carrier, thereby allowing the solid-state image exposure element array to carry an image. 2. The image forming apparatus according to claim 1, wherein a positional shift along a rotation direction of the body is detected. 7. The solid-state image exposing elements located in the vicinity of at least one end of each solid-state image exposing element array are used as a set of a predetermined number of solid-state image exposing elements. The image carrier of the solid-state image exposure device array is turned on simultaneously at different gradations for each image exposure device along the axial direction of the image carrier, and the amount of light emitted by the solid-state image exposure device is detected by a light-receiving device. 2. The image forming apparatus according to claim 1, wherein a positional displacement along an axial direction of the image forming apparatus is detected. 8. The solid-state image exposing element located in the vicinity of at least one end of each solid-state image exposing element array as a set of a predetermined number of solid-state image exposing elements. At different gradations for each image exposure element, lighted simultaneously along the axial direction of the image carrier, the light emission amount of the solid-state image exposure element, through a slit inclined along the rotation direction of the image carrier, 2. The method according to claim 1, wherein the detection is performed by a light receiving element to detect a displacement of the image carrier of the solid-state image exposure element array along the rotation direction.
The image forming apparatus as described in the above. 9. The position shift detecting unit turns on a solid state image exposure element located near at least one end of each solid state image exposure element array to form a position shift detection pattern on the image carrier. 2. The image forming apparatus according to claim 1, wherein a position shift of the image carrier of the solid-state image exposure element array in the axial direction and the rotation direction is detected by detecting the position shift detecting pattern. apparatus. 10. The apparatus according to claim 1, wherein the position shift detecting means is configured to detect two adjacent positions.
While extinguishing a predetermined number of solid-state image exposure elements located near the end of one of the solid-state image exposure element arrays, the solid-state image exposure element array is positioned near the lighting position of the one solid-state image exposure element array. By continuously lighting a predetermined number of solid image exposure elements of the other solid image exposure element array, and sequentially moving the lighting position of the other solid image exposure element array along the axial direction of the image carrier. By sequentially forming linear images along the rotation direction of the image carrier, and detecting the reflectance on a straight line corresponding to the position of the one solid-state image exposure element array that is turned off, the solid-state image is formed. 2. The image forming apparatus according to claim 1, wherein a displacement of the exposure element array along the axial direction of the image carrier is detected. 11. The method according to claim 11, wherein the position shift detecting means is configured to detect two adjacent positions.
Of the two solid-state image exposure element arrays, while continuously lighting a predetermined number of solid-state image exposure elements located near the end of one of the solid-state image exposure element arrays, the lighting position of the one solid-state image exposure element array A predetermined number of the solid-state image exposure elements of the other solid-state image exposure element array located in the vicinity are continuously turned on, and the other solid-state image exposure element array itself is sequentially moved along the axial direction of the image carrier. By sequentially forming a linear image along the rotation direction of the image carrier, by detecting the reflectance of the linear image,
2. The image forming apparatus according to claim 1, wherein a displacement of the solid-state image exposure element array along the axial direction of the image carrier is detected. 12. The apparatus according to claim 12, wherein the position shift detecting means is configured to detect two adjacent positions.
Of the two solid-state image exposure element arrays, while continuously lighting a predetermined number of solid-state image exposure elements located near the end of one of the solid-state image exposure element arrays, the lighting position of the one solid-state image exposure element array Only a predetermined number of the solid-state image exposure elements of the other solid-state image exposure element array located in the vicinity are turned off and the other solid-state image exposure elements are turned on, and the other solid-state image exposure element array itself is moved to the axis of the image carrier. The image carrier is sequentially moved along the direction to form linear images along the rotation direction of the image carrier at predetermined intervals along the rotation direction of the image carrier, and the rotation direction of the image carrier is changed. By detecting the reflectance at the position where the linear image along the line and the linear image along the axial direction of the image carrier intersect, the linear image along the axial direction of the image carrier of the solid-state image exposure element array is detected. Misalignment detected The image forming apparatus according to claim 1, wherein Rukoto. 13. The solid-state image exposure device according to claim 1, wherein the position shift detection unit turns on a solid-state image exposure element located near at least one end of each solid-state image exposure element array to form a predetermined image on an image carrier. 2. The image forming apparatus according to claim 1, wherein a predetermined image formed on the image carrier is detected to detect a displacement of a focal position of the solid-state image exposure element array. 14. The position shift detecting means rotates each solid image exposure element array to a position shift detection position different from the image exposure position of the image carrier, and a light receiving element disposed at the position shift detection position, 2. The image forming apparatus according to claim 1, wherein a position shift of the solid image exposure element array is detected by detecting a light emitting position of the solid image exposure element. 15. The exposure unit corrects an exposure position of the solid-state image exposure element array by moving the solid-state image exposure element array in at least one of the axial direction and the rotation direction of the image carrier by a movement unit. The image forming apparatus according to claim 1, wherein: 16. The image forming apparatus according to claim 15, wherein said moving means is made of a shape memory alloy which is connected to an end of the solid-state image exposure element array and contracts by energization. 17. The moving means comprises a shape memory alloy connected to one end of the solid-state image exposure element array and contracted by energization, and a tension spring connected to the other end. 17. The image forming apparatus according to claim 16, wherein: 18. The apparatus according to claim 1, wherein the moving means is made of a shape memory alloy which is connected to both ends of the solid-state image exposure element array and contracts by energization.
7. The image forming apparatus according to 6. 19. The moving means includes a cam arranged to be engaged with at least one end of the solid-state image exposure element array, and contracts by energization on both radial sides of the rotation center of the cam. By connecting the shape memory alloys respectively, and selectively energizing the shape memory alloys, the shape memory alloys are contracted to rotate the cam,
2. The image forming apparatus according to claim 1, wherein a skew position shift of the solid-state image exposure element array is corrected. 20. When the solid-state image exposure element array is divided into a plurality of blocks and lit, the correcting means controls the lighting order of the plurality of divided blocks of the solid-state image exposure element array. 2. The image forming apparatus according to claim 1, wherein a displacement of one line or less of the solid-state image exposure element array along the rotation direction of the image carrier is corrected. 21. The correction means controls brightness when lighting a solid-state image exposure element located near at least one end of each solid-state image exposure element array,
2. The image forming apparatus according to claim 1, wherein the displacement of the solid-state image exposure element array along the axial direction of the image carrier is corrected. 22. The solid-state image exposure element array according to claim 22, wherein the correction means controls a lighting area of the solid-state image exposure element array to correct an exposure position of the solid-state image exposure element array along an axial direction of the image carrier. Item 2. The image forming apparatus according to Item 1. 23. The solid-state image exposure element array controls a lighting start position, an end position, and an image data switching position of each solid-state image exposure element array according to a shift amount of each solid-state image exposure element array in the main scanning direction. 2. The image forming apparatus according to claim 1, wherein the exposure position of the solid-state image exposure element array along the axial direction of the image carrier is corrected. 24. The image bearing device according to claim 19, wherein the correction unit corrects an angle between a plurality of solid-state image exposure element arrays arranged along a rotation direction of the image carrier, so that the image carrier associated with rotation fluctuation of the image carrier. 2. The image forming apparatus according to claim 1, wherein a position shift of the solid-state image exposure element array along a rotation direction of the body is corrected. 25. A correction means for correcting a mounting angle of a plurality of solid-state image exposure element arrays along a rotation direction of an image carrier, thereby providing a plurality of solid-state image exposure element arrays arranged along the rotation direction of the image carrier. 2. The image forming apparatus according to claim 1, wherein the displacement of the focal position of the solid-state image exposure element array is corrected. 26. A plurality of linear solid-state image exposure element arrays are arranged along the axial direction of the image carrier such that at least adjacent solid-state image exposure element arrays have different positions in the rotation direction of the image carrier. An image forming apparatus that forms an image by dividing the entire image width of the image carrier by the plurality of solid-state image exposure element arrays and exposing the image; An image forming apparatus comprising: a correction unit configured to correct at least one of a position shift in an axial direction and a rotation direction and a focal position; and an input unit configured to input a correction amount of the correction unit.