JP2008284760A - Exposure device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure device which can detect a tilting amount (skew amount) in a main scan direction of the exposure device equipped with a light emitting element array comprised of a plurality of light emitting elements in the shape of an array, and of an image carrier by a simple configuration and by a high precision of not larger than one line, and to provide an image forming apparatus which can highly precisely correct skew on the basis of the detected skew amount. <P>SOLUTION: The exposure device which forms an image on the image carrier by exposing the image carrier (photoreceptor 101) is equipped with the light emitting element array comprised of the plurality of light emitting elements 40, and a light receiving part (photo detection sensors 1a and 1b) which is set corresponding to the light emitting element (40ad) of a part that constitutes the light emitting element array, and which detects light that enters from outside of the exposure device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an exposure apparatus and an image forming apparatus that scan a dot pattern on a recording medium according to image information, and more particularly to a technique for improving image quality.

  In recent years, image forming apparatuses that form color images have been widely put into practical use. In particular, a color image forming apparatus having a plurality of image carriers (hereinafter referred to as a tandem type image forming apparatus) takes advantage of the productivity of image formation, and makes one copy by conventional multiple rotations (for example, four rotations). It has been developed along with a color image forming apparatus of an obtained type.

  As an image forming principle of the apparatus, an electrostatic latent image is formed on a recording medium (photoreceptor) charged in advance at a predetermined potential according to image information, and the electrostatic latent image is developed with toner and developed. A so-called electrophotographic process is applied in which an imaged toner image is transferred onto a recording paper and heat-fixed to obtain an image. As the exposure device, a method of forming an electrostatic latent image by scanning a light beam using a laser diode as a light source through a polygonal mirror called a polygon mirror that rotates at high speed (hereinafter referred to as a laser scanning method). Has been mainstream.

  However, in such a laser scanning method, a corresponding space is required between the polygon mirror and the photosensitive member in order to scan the laser beam between both ends in the main scanning direction of the photosensitive member. Further, since the polygon mirror is rotated by a motor, it is difficult to reduce the size of the laser beam scanning system. Therefore, it is difficult to reduce the size of the image forming apparatus using the laser scanning method. In addition, since the laser beam is incident on the photoconductor at a large angle near the edge of the photoconductor, problems such as deformation of the laser beam are likely to occur, and fluctuations in the image due to fluctuations at each rotation period of the polygon mirror occur. It is also known to be easy to do.

  On the other hand, each light emitting element is individually turned on (ON / OFF) using a light emitting diode (hereinafter referred to as an LED) or a light emitting element array in which light emitting elements constructed using an organic electroluminescent material are arranged in a line. A method (hereinafter referred to as a line scanning method) for forming an electrostatic latent image on the photoreceptor by controlling) is drawing attention. The line scanning method is a promising method in the future because it can be downsized as compared with the laser scanning method and there is no fluctuation on the image due to the fluctuation of each rotation period of the polygon mirror.

  By the way, in an image forming apparatus equipped with an exposure device composed of LEDs, there is a large variation in luminance for each LED chip. Therefore, it is necessary to take measures against luminance unevenness such as selection of LED chips and luminance adjustment by a drive circuit. It becomes a factor.

  In recent years, development of devices using organic electroluminescence elements (hereinafter referred to as organic EL elements) has been actively conducted by research institutes and companies, and some manufacturers have developed for commercialization. ing. Such an organic EL element can be manufactured on a glass substrate or a film in a lump, and by applying it to an image forming apparatus, luminance unevenness is reduced, optical system is downsized, and cost is reduced. Is considered promising.

  However, since the organic EL element has a low emission intensity per unit area, in order to obtain an output for forming a latent image on the photoreceptor, a higher voltage is applied to the organic EL element than when used as a display. It is necessary to pass a current of density. However, when the voltage applied to the organic EL element is increased to increase the current density of the flowing current, there is a problem that the light emission efficiency of the organic EL element is lowered and its life is also reduced. It is being done.

  On the other hand, as one of the recent trends in image forming apparatuses, there is an increasing demand for higher resolution and high-quality color reproduction of images. If there is a color shift in a color character or a color photographic image, the resolution and the color reproducibility deteriorate, but it is known that the above-described tandem type image forming apparatus is likely to generate a color shift in terms of the structural principle. The tandem image forming apparatus forms four-color images of Y (yellow), M (magenta), C (cyan), and K (black) in the main scanning direction substantially perpendicular to the recording paper conveyance direction (sub-scanning direction). Four exposure heads are arranged in parallel. In order to prevent color misregistration, each of the exposure apparatuses needs to maintain a high degree of parallelism with each other. However, there is no difference between the direction of the exposure head provided for each of the four colors and the main scanning direction. Even if the shift (hereinafter referred to as “skew”) is a shift of several dots of 600 dpi (dot / inch), the above-described positional shift between four colors (skew color registration) occurs, and a high-quality image is obtained. I couldn't.

  Various proposals have been made for improving image quality degradation due to such skew.

  For example, in (Patent Document 1), a misregistration detection pattern is printed on both ends of the main scanning direction on the suction belt, a reading skew amount is calculated by an obliquely arranged CCD sensor, and fed back to the adjustment mechanism of the laser optical system. An image forming apparatus is disclosed.

  (Patent Document 2) detects the toner image formed on the intermediate transfer member, calculates the skew amount, controls the data structure of the line memory, updates the lighting position of the element group of the LED head, A technique for performing skew correction is disclosed.

  Further, (Patent Document 3) discloses a technique for detecting the inclination of scanning light in the main scanning direction.

  FIG. 19 is an explanatory diagram for explaining a configuration for detecting the inclination of the scanning light in the main scanning direction in the conventional example, and shows the technique disclosed in (Patent Document 3).

  According to FIG. 19, in order to detect the inclination of the scanning light, detection markers 21 and 22 are provided at both ends in the scanning range on the photosensitive drum 20 in the image forming apparatus using the laser optical system as an exposure source. Are provided with optical sensors 31 and 32 for detecting reflected light of scanning light (see FIG. 19A). The error ΔH in the sub-scanning direction of the detection marker 22 due to the inclination of the scanning light in the main scanning direction is the difference in detection time Tfr between the bottoms of the detection marks 21 and 22 and the process speed (sub-scanning speed) as shown in FIG. ) It is calculated | required by (Formula 1) from Vp.

ΔH = Vp × Tfr (Equation 1)
Therefore, the detection time difference ΔTfr which is the difference between the detection start timing of the reflected light of the scanning light at the detection mark 21 by the optical sensor 31 and the detection start timing of the reflected light of the scanning light at the detection mark 22 by the optical sensor 32 is measured. Thus, the inclination in the main scanning direction can be detected as the scanning state of the scanning light.
Japanese Patent Application Laid-Open No. 09-174942 JP 2002-337384 A JP 2004-230722 A

  However, in the techniques disclosed in (Patent Document 1) and (Patent Document 2), since it is necessary to form a toner image pattern for detecting the skew amount, an increase in load power and noise in the image forming apparatus during print formation There is a problem in terms of cost and environment because generation, increase in toner consumption, and deterioration of the image carrier over time are promoted and the life is shortened.

  Further, in the techniques disclosed in (Patent Document 1), (Patent Document 2), and (Patent Document 3), it is necessary to individually provide a plurality of light detection means in the apparatus body, and the cost of members including peripheral members is increased. It is necessary to assemble, adjust, etc. at the time of manufacture. In addition, since any technique calculates the skew amount, the control step for calculation is complicated.

  Further, in (Patent Document 3), a skew amount of one line or less of laser scanning cannot be detected.

  The present invention has been made in view of the above problems, and provides an exposure apparatus capable of detecting a skew amount with a simpler configuration and with a high accuracy of one line or less as compared with the conventional example. With the goal.

  An exposure apparatus of the present invention is an exposure apparatus that exposes an image carrier to form an image on the image carrier, and comprises a light emitting element array composed of a plurality of light emitting elements and the light emitting element array. A light receiving unit is provided corresponding to a part of the light emitting elements and detects light incident from the outside of the exposure apparatus.

  According to the exposure apparatus of the present invention, since the light receiving part is built in the exposure apparatus, it is not necessary to provide the light receiving part in the main body of the image forming apparatus. This eliminates the need for assembly and adjustment of the light receiving part, and can improve production efficiency. In addition, since the light emission timing of the light emitting element corresponding to the light receiving portion can be arbitrarily set, the skew amount can be detected with high accuracy.

  An exposure apparatus of the present invention is an exposure apparatus that exposes an image carrier to form an image on the image carrier, and comprises a light emitting element array composed of a plurality of light emitting elements and the light emitting element array. A light receiving unit is provided corresponding to a part of the light emitting elements and detects light incident from the outside of the exposure apparatus.

  Since the light receiving part is built in the exposure device, it is not necessary to place the light receiving part in the image forming apparatus main body, so the light receiving part mounting member is not required, the material cost can be reduced, and the light receiving part is assembled and adjusted during manufacturing. The production efficiency can be improved. In addition, since the light emission timing of the light emitting element corresponding to the light receiving portion can be arbitrarily set, the skew amount can be detected with high accuracy.

  An exposure apparatus according to the present invention is an exposure apparatus that exposes an image carrier to form an image on the image carrier, the light-emitting element array including a plurality of first light-emitting elements, and the light-emitting elements. A second light emitting element provided outside the array range of the row and a light receiving unit provided corresponding to the second light emitting element and detecting light incident from the outside of the exposure apparatus are provided. .

  Since the light receiving part is built in the exposure device, it is not necessary to place the light receiving part in the image forming apparatus main body, so the light receiving part mounting member is not required, the material cost can be reduced, and the light receiving part is assembled and adjusted during manufacturing. The production efficiency can be improved. In addition, since the light emission timing of the light emitting element corresponding to the light receiving portion can be arbitrarily set, the skew amount can be detected with high accuracy.

  According to the present invention, the light receiving unit is configured to detect light reflected from a marker formed in advance on the exposed portion exposed by the exposure apparatus.

  Thus, the light receiving unit detects reflected light from a marker provided in advance in the exposure unit, so that it is not necessary to form a toner image and toner consumption can be reduced.

  In the present invention, a common optical system for guiding the light emitted from the plurality of first light emitting elements and the light emitted from the second light emitting elements to the outside of the exposure apparatus is provided.

  Accordingly, since the members and manufacturing processes of the conventional exposure apparatus can be used as they are, the detection function can be added while maintaining the conventional cost.

  In the present invention, the second light emitting element and the light receiving portion are respectively arranged at positions on both extension lines in the arrangement direction of the light emitting element rows.

  Thereby, the inclination of the light emitting element array with respect to the image carrier in the main scanning direction can be detected.

  In the present invention, the driving unit and the light receiving unit for driving the light emitting element are made of polysilicon.

  As a result, the light receiving part is formed by the same process as the driving part of the light emitting element, so that the function can be improved without increasing the manufacturing cost for adding the light receiving part. Further, since polysilicon is less deteriorated with time than, for example, amorphous silicon, stable light receiving characteristics can be maintained over a long period of time.

  In the present invention, the light emitting element array and the light receiving portion are formed on the same surface of the same substrate.

  As a result, the light emitting element array and the light receiving section are formed by a series of processes, and manufacturing at low cost becomes possible.

  According to the present invention, the light emitting element array and the light receiving portion are arranged separately on the surface of the substrate.

  As a result, it is possible to prevent light output from the light emitting element from directly entering the light receiving unit, and to improve detection accuracy.

  In the present invention, an organic electroluminescence element is used as a light emitting element.

  Thereby, it is possible to provide an inexpensive exposure apparatus with a simpler manufacturing process as compared with the case where an optical semiconductor such as an inorganic LED is used.

  In addition, the image forming apparatus of the present invention includes a light emitting element array composed of a plurality of first light emitting elements, a second light emitting element provided outside the arrangement range of the light emitting element array, and the second light emitting element. An exposure unit that is provided corresponding to the element and that includes a light receiving unit that detects light incident from the outside, an image carrier on which light scanning in the main scanning direction is performed by the light emitting element row, and an image is formed; Position update means for detecting reflected light from a predetermined area at both ends of the image carrier in the main scanning direction of the image carrier by the second light emitting element, and updating the positional relationship between the exposure unit and the image carrier based on the detection result And an image forming apparatus.

  This eliminates the need to adjust the position of the exposure unit with respect to the image carrier during manufacturing, and does not require high-precision components, so that the cost can be reduced, and the reflected light can be sequentially reflected against positional deviation in the field. Since the displacement can be detected based on the detection result, stable image quality can always be maintained.

  In the present invention, markers are formed at both ends of the image carrier in the main scanning direction, and the irradiation light from the exposure unit is irradiated onto the marker to detect the difference in rising or falling time of each reflected light from the marker. The updating operation of the positional relationship between the exposure unit and the image carrier is continued so as to reduce the time difference.

  This makes it possible to detect the tilt in the main scanning direction with the image carrier of the exposure apparatus without forming a toner image on the image carrier, thereby reducing toner consumption, scattered toner, and image carrier consumption. By doing so, it is possible to extend the life of the image carrier.

  Further, in the present invention, the light emission start timing of the second light emitting element is set to be after a predetermined time has elapsed from the extinction after the marker detection.

  Thus, by providing a turn-off time for the second light emitting element during the marker detection operation, the life of the light emitting element can be extended.

  Specific examples of the present invention are described in detail below.

Example 1
FIG. 1 is a schematic configuration diagram of an image forming apparatus in Embodiment 1 of the present invention.

  In FIG. 1, as one configuration example of an image forming apparatus having a photoconductor as an image carrier, four photoconductors 101, 102, 103, and 104, and a transfer unit 105 extending over these photoconductors are shown. A so-called tandem type color image forming apparatus is shown. There are charging devices 106, 107, 108, 109, exposure devices 110, 111, 112, 113, developing devices 114, 115, 116, 117, and photoconductor cleaning devices around the respective photoconductors 101, 102, 103, 104. 118, 119, 120, 121 are arranged.

  The developer storage units 122, 123, 124, and 125 store toners of colors corresponding to the developing devices 114, 115, 116, and 117, respectively, and the toners stored in them are stored in the image recorded on the paper. The developing devices 114 to 117 are replenished so that the density becomes substantially constant.

  The transfer unit 105 includes a belt-shaped transfer body 126, a driving roller 127 for rotating and conveying the belt-shaped transfer body 126, a pressing roller 129 for applying a pressing force to the belt-shaped transfer body 126 via the recording paper 128, A support roller 130 located on the opposite side of the drive roller 127 with the recording paper 128 interposed therebetween, and a belt-like transfer body 126 is in contact with the photoreceptors 101 to 104 of the belt-like transfer body 126 by applying a tension during image formation. Or it is comprised with the tension | tensile_strength roller 131 etc. for planarizing the opposing surface.

  In the first embodiment, the belt-like transfer body 126 constitutes a so-called intermediate transfer body that transfers a toner image directly on the surface thereof and then transfers it to the recording paper 128. Instead, for example, the paper is adsorbed on the belt. A so-called transfer paper transport body that transfers a toner image onto the paper may be used.

  The transfer unit 105 is provided with a belt cleaning device 132 for cleaning so-called residual toner that is not transferred onto the recording paper 128 but remains on the surface of the belt-like transfer body 126.

  In addition, the color image forming apparatus shown in FIG. 1 has a paper feed cassette 133 for storing the recording paper 128, and the recording paper 128 is transferred from the paper feeding cassette 133 by the support roller 130 and the pressing roller 129. A sheet feeding roller 135 for supplying to the section 134, a pickup roller 136, a registration roller 137, and the like, and a fixing device 139 for fixing the toner image transferred on the surface of the recording paper 128 are provided. It has been.

  FIG. 2 is a cross-sectional view of the exposure apparatus mounted on the image forming apparatus in Embodiment 1 of the present invention.

  Hereinafter, the configuration of the exposure apparatus according to the first embodiment will be described with reference to FIG.

  The color image forming apparatus according to the first embodiment includes the exposure apparatuses 110 to 113 corresponding to the plurality of photoconductors 101 to 104, but all have the same configuration. One photoconductor 101 and an exposure apparatus 110 that exposes the photoconductor 101 will be described.

  In Example 1, an organic electroluminescence element (hereinafter referred to as an organic EL element) is employed as the light emitting element 40 that exposes the photoreceptor 101. A light-emitting element array in which the light-emitting elements 40 composed of the organic EL elements are arranged at a pitch corresponding to, for example, 600 dpi (that is, 42.3 μm) is formed on a glass substrate 44, and the glass substrate 44 has a long length. It is held in the housing 41 (extends in the direction toward the back of the page in FIG. 2). The glass substrate 44 is fixed at a predetermined position of the exposure apparatus 110 by fixing through a screw insertion hole (not shown) via positioning pins (not shown) provided at both ends of the long housing 41.

  The light emitting element 40 is driven by a thin film transistor 51 (hereinafter referred to as TFT, see FIG. 3) formed on the same glass substrate 44 as the light emitting element 40.

  The gradient index rod lens array 46 is formed by stacking gradient index rod lenses on the front surface of the light emitting element 40, and constitutes an imaging optical system.

  Reference numeral 48 denotes a cover provided on the housing 41. The housing 41 covers the periphery of the glass substrate 44 and the side facing the photoreceptor 101 is open.

  In such a structure, the light emitted from the light emitting element 40 formed on the glass substrate 44 is imaged on the surface of the photoreceptor 101 by the rod lens array 46.

  A light absorbing member (paint) (not shown) is provided on the surface of the housing 41 that faces the end surface of the glass substrate 44.

  In the first embodiment, the light emitted from the light emitting element 40 is configured to enter the rod lens array 46 described above through the glass substrate 44 (that is, the bottom emission structure), and thus the light emitting element 40 is formed. The substrate needs to be made of a transparent material like the glass substrate 44, but is a so-called top emission type that outputs light emitted from the light emitting element 40 without passing through the substrate on which the light emitting element 40 is formed. Also good. In this case, a ceramic substrate or the like may be used instead of the glass substrate 44. The light emitting element array formed on the glass substrate 44 is sealed with a glass plate (not shown).

  FIG. 3 is a plan view showing the configuration of the organic EL light-emitting element array in Example 1 of the present invention.

  As shown in FIG. 3, the glass substrate 44 mounted on the exposure apparatus 110 of Example 1 includes light emitting elements 40_0001 to 40_5120 (that is, 5120) that are responsible for image formation arranged in the main scanning direction, and glass similarly. Light receiving sensor 1a that is provided corresponding to light emitting elements 40a, 40b, 40c, 40d for skew measurement and light emitting elements 40a, 40b for skew measurement provided on substrate 44 and detects light from the outside of exposure apparatus 110. The light receiving sensor 1b is provided corresponding to the skew measuring light emitting elements 40c and 40d, and detects light from outside the exposure apparatus 110.

  A so-called electrostatic latent image is formed on the photosensitive member 101 (see FIG. 2) by controlling lighting / extinction of the light emitting elements 40_0001 to 40_5120 responsible for the image formation according to the image data.

  In the following description, among the light emitting elements 40, the light emitting elements responsible for image formation will be collectively referred to as the light emitting element 40pel. Further, when the light emitting elements for skew measurement are collectively described, they are described as the light emitting element for skew measurement 40ad.

  A driver circuit 51 includes a TFT and supplies current to the light emitting element 40pel and the skew measuring light emitting element 40ad (hereinafter referred to as TFT 51).

  In FIG. 3, the interval between the skew measuring light emitting element 40 b and the light emitting element 40 — 0001 responsible for image formation is drawn close to each other for convenience, but actually, the skew measuring light emitting element 40 b is outside the image forming area of the photoconductor 101. (Same for all of the skew measuring light emitting elements 40ad).

  The skew measuring light emitting element 40ad is provided on the same surface of the light emitting element 40pel and the glass substrate 44 at a predetermined interval.

  The skew measuring light emitting element 40ad of Example 1 is generated at the same time as the light emitting element 40pel by distributing a polymer electroluminescent material, and constitutes a so-called organic EL element.

  Further, the light receiving sensors 1a and 1b are also collectively generated by a manufacturing process similar to that of the TFT 51, for example, a polysilicon forming process. There is an advantage that the function is improved without increasing the cost.

  Here, in Example 1, the number of light emitting elements 40ad for skew measurement is four, but the number may be increased if the amount of light is insufficient, and the light emitting region (area) of the light emitting element 40ad for skew measurement is configured to be large. (In this case, the number may be reduced). In the first embodiment, the skew measuring light emitting element 40ad is provided separately from the light emitting element row formed by the light emitting element 40pel responsible for image formation. However, the number of light emitting elements constituting the light emitting element row is set as described above. More than 5120 may be formed, and among them, the light emitting element provided in the vicinity of the light receiving sensors 1a and 1b may be used as the light emitting element for skew measurement. In this case, a part of the light emitting element 40pel is used as a light emitting element for skew measurement.

  In the first embodiment, the light receiving sensors 1a and 1b are provided at positions separated in the sub-scanning direction with respect to the light emitting element row formed by the light emitting element 40pel that bears an image. You may make it provide in the position shown on the substantially extended line of an element row | line, ie, Pos1 and Pos2. In this case, since the light receiving sensors 1a and 1b do not interfere with the arrangement position of the TFT 51, there is an advantage that the design of the TFT 51 becomes easy.

  FIG. 4 is a block diagram showing an exposure control block for controlling the position of the exposure apparatus 110 in Embodiment 1 of the present invention.

  In FIG. 4, reference numeral 1 denotes a light receiving sensor for detecting the reflected light of the photosensitive member 101, which corresponds to the light receiving sensors 1a and 1b already described (hereinafter referred to as the light receiving sensor 1 in the case of the light receiving sensors 1a and 1b). Point to one). 2 is an A / D converter for quantizing the analog light quantity level of the light receiving sensor 1, 3 is a control unit for recognizing the light quantity level quantized by the A / D converter 2 and performing arithmetic control, and 5 is an image. A support member that is attached to a housing of a forming apparatus (not shown) and includes actuators 5a and 5b therein. The support member 5 is disposed substantially parallel to the exposure apparatus 110, and the actuators 5a and 5b are provided at both ends in the longitudinal direction of the support member 5 (for the actuators 5a and 5b, FIG. 8 and FIG. 13).

  An actuator driving unit 4 drives the actuators 5a and 5b. The actuators 5a and 5b are driven based on a movement amount control signal from the control unit 3.

  Reference numeral 6 denotes a drive circuit for causing the skew measuring light emitting element 40ad to emit light. In response to a lighting signal from the control unit 3, a supply current flows from the driving circuit 6 to the skew measuring light emitting element 40ad, and light emission is started. The light flux forms an image on the photosensitive member 101 via

  The light reflected from the surface of the photosensitive member 101 is incident on the light receiving sensor 1 again via the rod lens array 46.

  FIG. 5 is an explanatory diagram of the imaging optical system centering on the rod lens array 46 in the first embodiment of the present invention.

  In FIG. 5, when the working distance that is the distance from the end face of the rod lens array 46 to the object or the image plane is L0, and the length of the rod lens array 46 itself is Z0, the conjugate length Tc of the rod lens array 46 is Tc. = Z0 + 2 × L0.

  The light emitting element 40 (both the light emitting element 40pel responsible for image formation and the light emitting element 40ad for skew measurement) and the rod lens array 46 in the exposure apparatus 110 so that the light beam is completely imaged (focused) on the photosensitive member 101. And the photosensitive member 101 are in a conjugate relationship as described above.

  With such a configuration, both the light emitted from the skew measuring light emitting element 40ad and the light emitting element 40pel responsible for image formation are imaged on the surface of the photoreceptor 101 by the rod lens array 46.

  FIG. 6 is a configuration diagram showing the configuration of the photoconductor 101 built in the image forming apparatus according to the first embodiment of the present invention.

  As shown in FIG. 6, detection markers M <b> 1 and M <b> 2 are provided on the photoreceptor 101 outside the image forming area in the main scanning direction. The detection markers M1 and M2 are formed to have different reflection characteristics from the surface of the photosensitive member 101.

  The detection markers M1 and M2 are for measuring the absolute position in the rotation direction of the photosensitive member 101, and are not formed by the toner image when measuring the skew amount, but are fixed patterns.

  For example, when the surface of the photoconductor 101 exhibits strong regular reflection characteristics, the detection markers M1 and M2 are formed to have strong diffuse reflection characteristics by partially roughening the surface of the photoconductor 101. Alternatively, it is formed by distributing a paint having good absorption characteristics with respect to the wavelength of the light emitting element 40 composed of an organic EL element. Conversely, when the surface of the photoconductor 101 has diffuse reflection characteristics, the surface of the photoconductor 101 is partially mirror-polished so as to have strong regular reflection characteristics. Further, the positions of the detection markers M1 and M2 in the sub-scanning direction are formed so as to be at the same interval with respect to the reference line P0 parallel to the main scanning direction of the photosensitive member 101 (that is, Δp1 = Δp2). In the first embodiment, the photoconductors 102 to 104 have the same configuration.

  Based on the configuration of the image forming apparatus described above, a process of skew correction when the exposure apparatus 110 is tilted with respect to the main scanning direction of the photoconductor 101 (hereinafter referred to as skew) will be described.

  7, 8, and 9 are explanatory diagrams for explaining the process of skew correction in the first embodiment of the present invention.

  As shown in FIGS. 7 and 8, the optical positional relationship between the detection markers M1 and M2 on the photosensitive member 101 and the skew measuring light emitting element 40ad and the light receiving sensors 1a and 1b provided in the exposure apparatus 110 is the skew. The emitted light output from the measurement light emitting elements 40a and 40b irradiates the detection marker M1, and the reflected light is incident on the light receiving sensor 1a, and the output from the skew measurement light emitting elements 40c and 40d. The optical arrangement is made such that the incident light irradiates the detection marker M2 and the reflected light enters the light receiving sensor 1b (the detection markers M1 and M2 are mirror surfaces and have strong regular reflection). Configuration when showing characteristics).

  Alternatively, when the light emitted from the skew measuring light emitting element 40ad is irradiated on the surface of the photosensitive member 101 other than the detection markers M1 and M2, the reflected light may be incident on the light receiving sensors 1a and 1b. (The above is the case where the surface of the photoconductor 101 forms a mirror surface and the skew detection markers M1 and M2 form a diffusion surface).

  As described above, the exposure apparatus 110 according to the first exemplary embodiment is an exposure apparatus that exposes the image carrier (photosensitive body 101) to form an image on the image carrier, and is a light emitting element including a plurality of light emitting elements. A light emitting element 40a, 40b for skew measurement and a light emitting element 40pel responsible for image formation, and a part of the light emitting elements (light emitting element 40ad for skew measurement) constituting the light emitting element array, and exposure. It has light receiving portions (light receiving sensors 1a and 1b) for detecting light incident from the outside of the apparatus (that is, light reflected from the photosensitive member 101 which is an image carrier).

  In this configuration, if the light emitting element 40pel responsible for image formation is defined as a first light emitting element, and the skew measuring light emitting element 40ad is defined as a second light emitting element, the exposure apparatus 110 of Example 1 has a plurality of first light emitting elements. A light emitting element array composed of elements, a second light emitting element provided outside the arrangement range of the light emitting element array (that is, outside the image forming area), and a second light emitting element provided corresponding to the second light emitting element, In other words, the light receiving unit may detect light incident from the outside of the exposure apparatus.

  Next, the process of detecting and correcting the skew will be described with reference to FIGS.

  In the state shown in FIG. 8, the exposure device 110 is attached with a slight inclination with respect to the main scanning direction of the photoconductor 101. After the image forming apparatus is turned on, the photoconductor 101 is driven by an unillustrated driving means shown in FIG. It rotates in the direction of. At a predetermined time t0, the skew measuring light emitting element 40ad starts to emit light in response to a driving signal from the driving circuit 6 (see FIG. 9). When the surface of the photoconductor 101 exhibits strong specular reflection, the light receiving sensors 1a and 1b A high level of light is incident. When the detection markers M1 and M2 on the photosensitive member 101 approach the vicinity of the exposure apparatus 110, the emitted light beam from the skew measuring light emitting element 40ad irradiates the detection markers M1 and M2, and changes from regular reflection to diffuse reflection. . That is, when the detection markers M1 and M2 are detected, the amount of light incident on the light receiving sensors 1a and 1b decreases, and therefore the passing time of the leading or trailing end of the detecting markers M1 and M2 in the rotation direction R0 of the photosensitive member 101 is measured. can do.

  Thus, two timers (not shown) provided in the control unit 3 (see FIG. 4) start the timer from the light emission start time t0 as shown in FIG. 9, and the light quantity level incident on the light receiving sensors 1a and 1b is reduced. Each time is monitored independently (that is, the count value of the timer increases as the detection timing of the detection markers M1 and M2 is delayed). The light emitting element 40ad for skew measurement and the light emitting element 40pel responsible for image formation are arranged in parallel to the main scanning direction of the exposure apparatus 110, and as described above, the front end or rear end of the detection markers M1, M2 The exposure unit 110 is parallel to the main scanning direction of the photoconductor 101 if the respective times are the same, since the units are arranged at the same position in the sub-scanning direction of the photoconductor 101. However, if they are not simultaneously, they are skewed (inclined) with respect to the main scanning direction.

  It makes sense to use two timers as described above. If the timer is set to one system and the timer operation is started based on the detection timing of t2, for example, when the detection timings of t1 and t2 are reversed, the value of the timer count becomes large (worst case) The counting is continued for the time that the photosensitive member 101 makes a round). This is nothing but a difference in detection time between the detection of two events, and there is a possibility that an extra error component due to uneven rotation period of the photosensitive member 101 is mixed in the skew amount measurement.

  Now, the difference between t1 and t2 measured by two systems of timers, that is, the time difference Δt = t1−t2, has a sign (+ or −) indicating the skew direction, and an absolute value indicating the magnitude of the skew amount. In the first embodiment, this time difference Δt is multiplied by the driving speed of the photosensitive member 101k (process speed P shown in FIG. 9) to obtain a skew amount as distance information. The calculation of the skew amount is executed by the control unit 3 (see FIG. 4).

  Based on the skew amount calculated in this way, the control unit 3 outputs a correction amount (for example, a current value) to the actuator driving unit 4 (see FIG. 4).

  The correction of the skew amount is finally executed by actuators 5a and 5b (referred to as actuator 5ab when collectively described) arranged near exposure apparatus 110. That is, in the case of the inclination with respect to the main scanning direction as shown in FIG. 8 (that is, in the case of Δt> 0 (t2> t1)), the actuator 5b as the exposure head position moving means is based on the output of the actuator driving unit 4 as shown in FIG. The one side of the exposure apparatus 110 is moved in the arrow direction D1. Alternatively, the actuator 5a moves one side of the exposure apparatus 110 in the arrow direction D2.

  Thus, the actuator 5ab slightly moves both ends of the exposure apparatus 110 in the main scanning direction, and this operation can adjust the inclination of the exposure apparatus 110 in the main scanning direction. This moving operation is performed for each predetermined unit step, and the exposure apparatus 110 is also moved by a minute amount corresponding to the unit step.

  When Δt <0 (t2 <t1), the position of the exposure apparatus 110 is controlled in the direction opposite to the above-described direction.

  FIG. 10 is an explanatory diagram illustrating a skew correction operation according to the first embodiment of the present invention.

  FIG. 10 shows the positional relationship of the photosensitive member 101, the exposure device 110, and the actuators 5a and 5b when performing skew correction, as viewed from the side. The exposure device 110 follows the surface of the photosensitive member 101 by skew correction. To displace. Strictly speaking, the distance between the exposure apparatus 110 and the photosensitive member 101 varies due to skew correction. However, the amount of displacement actually adjusted by the skew correction is about ± 1 mm at most, and considering the curvature of the photosensitive member 101, the change in the focus height (that is, the focus shift) due to the skew correction hardly poses a problem.

  In the first embodiment, the photosensitive member 101 is described as a drum-shaped member. However, the photosensitive member 101 may be a belt. If the plane formed by the belt is exposed, the problem of curvature when a drum is used as the photosensitive member 101 can be ignored.

  FIG. 11 is a flowchart showing a control sequence of skew correction in the first embodiment of the present invention, and FIG. 12 is a timing chart showing operation timing of skew correction in the first embodiment of the present invention.

  Hereinafter, the skew correction operation will be specifically described with reference to FIGS. 11 and 12.

  In FIG. 11, when the photosensitive member 101 starts rotating (S001), after a predetermined time, the drive circuit 6 (see FIG. 4) sets the lighting signal for the skew measuring light emitting element 40ad to ON (S002). As a result, the skew measuring light emitting element 40ad starts to emit light (S003), and the ends of the detection markers M1 and M2 provided on the rotating photoconductor 101 are in the light irradiation region of the skew measuring light emitting element 40ad. When it reaches, the incident light amount level to the light receiving sensors 1a and 1b decreases (transition to the low level), and the times t1 and t2 at that time are measured (S004).

  Then, the position of the exposure apparatus 101 is updated by controlling the actuator 5a or the actuator 5b on the basis of the skew amount as the above-described distance information according to the magnitude relationship between t1 and t2 (S006, S007). .

  More specifically, the actuator drive signal 1 or 2 shown in FIG. 12 is output based on the skew direction. In FIG. 12, it is assumed that the above-described detection timing is t1> t2. In this case, the exposure apparatus 110 drives the actuator 5b (or the actuator 5a) based on the actuator drive signal in the direction D1 shown in FIG. (Or D2 direction).

  Thereafter, the skew measuring light emitting element 40ad is turned off (S008), turned on again after a predetermined time (S002), and the time when the light amount level decreases is detected as described above. The above operation is repeated for each rotation period of the photosensitive member 101 (see FIG. 12), and the position movement of the exposure head is completed when t1 and t2 become the same time (S009).

  Note that it is desirable to provide an appropriate margin for the simultaneity of t1 and t2. For example, the difference between t1 and t2 is within a predetermined range, that is, the skew amount (see FIG. 9) is within a predetermined range (for example, a resolution of 600 dpi). If necessary, a program that makes a transition from S005 to S009 at the time when it is within ¼ (about 10 μm) may be configured.

  FIG. 13 is a configuration diagram of a mechanism for adjusting the skew amount according to the first embodiment of the present invention.

  Hereinafter, the mechanism operation for adjusting the skew amount with respect to the photosensitive member 101 of the exposure apparatus 110 will be described with reference to FIG.

  FIG. 13 shows a mechanical concept of an actuator 5ab (not shown in FIG. 4) provided on the support member 5 shown in FIG.

  7a and 7b are solenoids for obtaining an attractive force by generating a magnetic field by a coil current, and are integrally provided on a support member 5 attached between chassis members 10a and 10b constituting a skeleton of the image forming apparatus. It has been.

  8a and 8b are elastic bodies constituted by coil springs, leaf springs, and the like, and 9a and 9b are plungers attached to the exposure apparatus 110 and are made of a magnetic material. Plungers 9a and 9b function as actuators in combination with solenoids 7a and 7b, and can move exposure apparatus 110.

  That is, first, a predetermined suction force is generated by the initial coil current, and the exposure apparatus 110 is moved to the right side in FIG. 13 and is stopped at a position where the elastic force with the elastic bodies 8a and 8b is balanced. If the coil current is increased in this state, the attractive force is further increased, and the exposure apparatus 110 moves further to the right as a whole, and if the coil current is decreased, the exposure apparatus 110 moves in the opposite direction. The movement signal for this movement is output from the control unit 3 shown in FIG. 4 to the actuator drive circuit 4 as described above. The coil current is changed in accordance with the signal level. If the amount of movement per step is 10 μm, for example, the coil currents of the solenoids 7a and 7b corresponding to the amount of movement are preset, and the movement signal is set so as to increase or decrease the coil current using the current value as a control unit. Just do it.

  FIG. 14 is a configuration diagram illustrating a modification of the actuator 5ab according to the first embodiment of the present invention.

  Hereinafter, modified examples of the moving mechanism of the exposure apparatus 110 will be described with reference to FIG.

  FIG. 14 shows a configuration example in which the solenoids 7a and 7b and the plungers 9a and 9b in FIG. 13 are replaced with other components. Reference numeral 5 denotes a supporting member, 80 denotes a stepping motor, 81 denotes a motor output shaft constituting a worm gear, 82 Is a cylindrical internal gear integrally attached to the exposure apparatus 110. The rotation of the stepping motor 80 moves the exposure apparatus 110 in the direction perpendicular to the rotation surface, that is, in the left-right direction in FIG. To do.

  By controlling the number of pulses input to the stepping motor 80 by a stepping motor control circuit (not shown) and controlling the step angle of the stepping motor 80, the amount of movement of the exposure apparatus 110 can be controlled.

  In addition to the above, movement control of the exposure apparatus 110 using an electrostrictive element or a magnetostrictive element is also conceivable. Here, a piezoelectric element such as PZT is used as the electrostrictive element, and the amount of displacement of the piezoelectric element is controlled by controlling the voltage applied to the piezoelectric element, and the exposure apparatus 110 can be moved via an appropriate mechanism. it can.

  A magnetostrictive element is a material that stretches itself when exposed to a magnetic field. A coil is formed in the vicinity of the magnetostrictive element to generate a magnetic field, and the amount of current supplied to the coil is controlled to vary the strength of the magnetic field. The exposure apparatus 110 can be moved by utilizing the expansion and contraction of the magnetostrictive element due to the change of the magnetic field.

  In the above description, two actuators 5a and 5b for displacing the exposure apparatus 110 are provided. However, the exposure apparatus 110 is supported in a cantilevered state at one end in the main scanning direction, and is opposite to the support side. An actuator may be attached to the head and the actuator may be controlled to correct the skew.

  In addition, the piezoelectric element may be configured to use, for example, a combination of a bimorph type and a laminated type, perform coarse adjustment with a bimorph type, and perform fine adjustment with a laminated type.

(Example 2)
FIG. 15 is a configuration diagram showing the configuration of the light emitting element formed on the glass substrate 44 in Example 2 of the present invention.

  Hereinafter, Embodiment 2 of the present invention will be described with reference to FIG.

  As shown in FIG. 15, the glass substrate 44 mounted on the exposure apparatus 110 of Example 2 includes light emitting elements 40_0001 to 40_5120 (that is, 5120) that are responsible for image formation arranged in the main scanning direction, and glass similarly. A light receiving sensor 1a for detecting light from the outside of the exposure apparatus 110 and a light emitting element for skew measurement provided corresponding to the light emitting elements for skew measurement 40x1 and 40x2 and the light emitting element for skew measurement 40x1 provided on the substrate 44. A light receiving sensor 1b that is provided corresponding to 40 × 2 and detects light from the outside of the exposure apparatus 110 is formed.

  A so-called electrostatic latent image is formed on the photosensitive member 101 (see FIG. 2) by controlling lighting / extinction of the light emitting elements 40_0001 to 40_5120 responsible for the image formation according to the image data.

  In the following description, among the light emitting elements 40, the light emitting elements responsible for image formation will be collectively referred to as the light emitting element 40pel. When the skew measuring light emitting elements are collectively described, they are described as the skew measuring light emitting elements 40x.

  Reference numeral 51 denotes a TFT that constitutes a driver that supplies current to the light emitting element 40pel. Reference numerals 51x1 and 51x2 denote TFTs that constitute a driver that supplies current to the skew measuring light emitting elements 40x1 and 40x2.

  In FIG. 15, the interval between the skew measuring light emitting element 40 x 1 and the light emitting element 40 — 0001 responsible for image formation is drawn close to each other for convenience, but actually, the skew measuring light emitting element 40 x is outside the image forming area of the photoreceptor 101. Be placed.

  The second embodiment is the same as the first embodiment except that the configuration of the skew measuring light emitting elements 40x1 and 40x2 on the glass substrate 44 is different. Therefore, the description of the configuration and the like of the image forming apparatus is omitted. To do.

  The light transmission efficiency of the rod lens array 46 described in the first embodiment is generally said to be about 6%, although it depends on the aperture angle. In the first embodiment, the light emitted from the light emitting element 40ad for skew measurement is imaged on the photosensitive member 101 via the rod lens array 46 as in the case of the other light emitting elements 40pel (see FIG. 2). Due to the low efficiency, a reduction in the amount of light on the image surface of the photoreceptor cannot be avoided, and the SN ratio is inevitably reduced when viewed as a measurement system. Since the skew correction detects the position of the detection target, an extremely high S / N ratio is not necessary, but if the S / N ratio of the signal system is lowered, there is a risk of false detection due to an increase in noise components, and therefore to some extent (for example, about 48 dB). The S / N ratio should be secured.

  On the other hand, in the second embodiment, this is dealt with by increasing the total light emission amount of the skew measuring light emitting element 40x. Specifically, the light emission areas of the light emitting elements 40x1 and 40x2 for skew measurement are set to 100 times the individual areas of the light emitting elements 40pel. In this case, the light emitting elements 40x1 and 40x2 for skew measurement are configured by a set of 10 × 10 light emitting elements (each size is 42.3 μm × 42.3 μm as in the light emitting element 40pel) in the main scanning direction and the sub scanning direction. is doing.

  Even in this case, the size of the light emitting element for skew measurement is at most about 0.5 mm × 0.5 mm, and only a small part of the glass substrate 44 is occupied.

  Further, in Example 2, the skew measurement light emitting element 40x is not a light emitting element contributing to image formation, unlike the other light emitting elements 40pel, and as a result, the cumulative lighting time is short, and the skew amount Is measured, the light emission amount of the skew measuring light emitting element 40x is significantly increased as compared with the other light emitting elements 40pel.

  Specifically, the drive current is set so that the amount of emitted light is about 10 times that of the other light emitting elements 40pel. The amount of light emitted when the skew measuring light emitting element 40x is caused to emit light by this drive current can be measured by the light receiving sensors 1a and 1b. Therefore, the drive current is regenerated so that the measured value becomes a predetermined value. If set, skew correction (detection of a pattern provided on the photosensitive member) can be executed stably at all times.

  Naturally, when driving the light emitting element with such a large current, it is necessary to increase the drive capability of the TFTs 51x1 and 51x2. In the second embodiment, for this problem, the TFT for driving the skew measuring light emitting element 40x and the TFT for driving the other light emitting element 40pel are separated, and a plurality of TFTs 51x1 and 51x2 for driving the skew measuring light emitting element 40x are provided. The thin film transistors were connected in parallel to drive the skew measuring light emitting element 40x.

(Example 3)
FIG. 16 is a configuration diagram showing the configuration of the light emitting element formed on the glass substrate 44 in Example 3 of the present invention.

  Hereinafter, Embodiment 3 of the present invention will be described with reference to FIG.

  As shown in FIG. 16, the glass substrate 44 mounted on the exposure apparatus 110 of Example 3 includes light emitting elements 40_0001 to 40_5120 (that is, 5120 elements) that are responsible for image formation arranged in the main scanning direction, and glass similarly. A light receiving sensor 1a for detecting light from outside the exposure apparatus 110 and a light emitting element for skew measurement provided corresponding to the light emitting elements for skew measurement 40z1 and 40z2 and the light emitting element for skew measurement 40z1 provided on the substrate 44. A light receiving sensor 1b that is provided corresponding to 40z2 and detects light from the outside of the exposure apparatus 110 is formed.

  A so-called electrostatic latent image is formed on the photosensitive member 101 (see FIG. 2) by controlling lighting / extinction of the light emitting elements 40_0001 to 40_5120 responsible for the image formation according to the image data.

  In the following description, among the light emitting elements 40, the light emitting elements responsible for image formation will be collectively referred to as the light emitting element 40pel. When the skew measuring light emitting elements are collectively described, they are described as the skew measuring light emitting elements 40z.

  Reference numeral 51 denotes a TFT that constitutes a driver that supplies current to the light emitting element 40pel. Reference numerals 51x1 and 51x2 denote TFTs that constitute a driver that supplies current to the light emitting elements 40z1 and 40z2 for skew measurement.

  In FIG. 16, the interval between the skew measuring light emitting element 40z1 and the light emitting element 40_0001 responsible for image formation is drawn close to each other for convenience, but actually the skew measuring light emitting element 40z is outside the image forming area of the photoconductor 101. Be placed.

  The third embodiment is the same as the first embodiment except that the configuration of the light emitting elements 40z1 and 40z2 for skew measurement on the glass substrate 44 is different. Therefore, the description of the configuration and the like of the image forming apparatus is omitted. To do.

  The greatest feature of the third embodiment is that the light receiving sensors 1a and 1b are surrounded by light emitting elements 40z1 and 40z2 for skew measurement.

  The light transmission efficiency of the rod lens array 46 described in the first embodiment has a distribution in the sub-scanning direction, and the transmission efficiency decreases as the distance from the center axis in the main scanning direction increases in the sub-scanning direction.

  On the other hand, in Example 3, since the skew measuring light emitting element 40z is provided so as to surround the light receiving sensors 1a and 1b, all the light emitting elements are arranged in the vicinity of the light receiving sensor. As a result, the influence of a decrease in transmission efficiency in the sub-scanning direction of the rod lens array 46 can be reduced as compared with the configuration shown in the first embodiment.

  FIG. 17 is a configuration diagram showing a modification of the third embodiment of the present invention.

  As shown in FIG. 17, the same effect can be obtained by providing cross-shaped light receiving sensors 1a and 1b at the center and disposing the skew measuring light emitting elements 40z1 and 40z2 at the four corners. Further, with such a configuration, the relative area of the light receiving sensors 1a and 1b can be increased, which is advantageous in terms of light receiving sensitivity.

Example 4
FIG. 18 is a block diagram showing the periphery of an exposure apparatus, particularly a light receiving sensor, in Embodiment 4 of the present invention.

  Hereinafter, a fourth embodiment of the present invention will be described.

  The fourth embodiment is different from the first embodiment in that the light receiving sensor is provided as a separate body, and the other components are common to the first embodiment.

  In FIG. 18, reference numeral 500 denotes a light receiving sensor, which is a chip component formed of, for example, a photodiode. One light receiving sensor 500 is arranged at each of both end portions of the exposure apparatus 110 in the main scanning direction of the exposure apparatus 110 (in FIG. 18, the back side of the paper surface).

  In the fourth embodiment, the light emitting element 40ad for skew measurement is formed on the glass substrate 44, and the emitted light reaches the photoconductor 101 via the glass substrate 44 and the rod lens array 46. The reflected light enters the light receiving sensor 50 without passing through the rod lens array 46.

  The optical positional relationship between the detection markers M1 and M2 on the photosensitive member 101 and the skew measuring light emitting element 40ad and the light receiving sensor 500 provided in the exposure apparatus 110 is determined by the light emitted from the skew measuring light emitting element 40ad. The detection marker M <b> 1 (M <b> 2) is irradiated, and the reflected light enters the light receiving sensor 500 directly.

  With this configuration, the problem that the light transmission efficiency of the rod lens array 46 is low (about 6% as already described) affects only the light emitted from the light emitting element, and the photosensitive member 101. There is no influence on the light reflected from (or the markers M1, M2). This makes it possible to measure the skew amount with high accuracy and less influence of noise.

  As described above, since the exposure apparatus and the image forming apparatus according to the present invention can detect an image skew amount with a simple configuration, an exposure apparatus such as a so-called optical head, and an MFP (Multi Function) equipped with the exposure apparatus. The present invention can be applied to an image forming apparatus using an electrophotographic process such as a printer, a printer, and a copying machine, or a printer that directly exposes photographic paper.

1 is a schematic configuration diagram of an image forming apparatus in Embodiment 1 of the present invention. Sectional drawing of the exposure apparatus mounted in the image forming apparatus in Example 1 of this invention The top view which shows the structure of the organic electroluminescent light emitting element array in Example 1 of this invention. The block block diagram which shows the exposure control block which controls the position of the exposure apparatus in Example 1 of this invention Explanatory drawing of the imaging optical system centering on the rod lens array in Example 1 of this invention 1 is a configuration diagram showing a configuration of a photoconductor built in an image forming apparatus according to Embodiment 1 of the present invention. Explanatory drawing explaining the process of the skew correction | amendment in Example 1 of this invention. Explanatory drawing explaining the process of the skew correction | amendment in Example 1 of this invention. Explanatory drawing explaining the process of the skew correction | amendment in Example 1 of this invention. Explanatory drawing which shows the skew correction operation | movement in Example 1 of this invention. 6 is a flowchart showing a control sequence for skew correction in Embodiment 1 of the present invention. Timing chart showing operation timing of skew correction in Embodiment 1 of the present invention Configuration diagram of a mechanism for adjusting the skew amount in Embodiment 1 of the present invention The block diagram which shows the modification of the actuator in Example 1 of this invention The block diagram which shows the structure of the light emitting element formed on the glass substrate in Example 2 of this invention The block diagram which shows the structure of the light emitting element formed on the glass substrate in Example 3 of this invention. The block diagram which shows the modification of Example 3 of this invention FIG. 6 is a block diagram showing the periphery of an exposure apparatus, particularly a light receiving sensor, in Embodiment 4 of the present invention. Explanatory drawing explaining the structure which detects the inclination of the main scanning direction of the scanning light in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b Light reception sensor 2 A / D converter 3 Control part 4 Actuator drive part 5 Support member 5a, 5b, 5ab Actuator 6 Drive circuit 7a, 7b Solenoid 8a, 8b Elastic body 9a, 9b Plunger 10a, 10b Chassis member 40 light emitting element 40pel light emitting element responsible for image formation (light emitting element)
40a, 40b, 40c, 40d, 40ad Light emitting element for skew measurement 40x1, 40x2, 40x Light emitting element for skew measurement 40z1, 40z2, 40z Light emitting element for skew measurement 44 Glass substrate 45 Light emitting part 46 Rod lens array 51, 51x1, 51x2 TFT (Thin film transistor)
80 Stepping motor 81 Motor output shaft 82 Internal gears 101, 102, 103, 104 Photoconductor 105 Transfer unit 106, 107, 108, 109 Charging device 110, 111, 112, 113 Exposure device 114, 115, 116, 117 Development device 118, 119, 120, 121 Photoconductor cleaning device 122, 123, 124, 125 Developer storage portion 126 Belt-shaped transfer body 127 Driving roller 128 Recording paper 129 Pressing roller 130 Support roller 131 Tension roller 132 Belt cleaning device 139 Fixing device 500 Light receiving sensor M1, M2 Detection marker

Claims (12)

An exposure apparatus that exposes an image carrier to form an image on the image carrier,
A light emitting element array composed of a plurality of light emitting elements;
A light receiving portion that is provided corresponding to a part of the light emitting elements constituting the light emitting element array and detects light incident from the outside of the exposure apparatus;
An exposure apparatus. An exposure apparatus that exposes an image carrier to form an image on the image carrier,
A light emitting element array composed of a plurality of first light emitting elements;
A second light emitting element provided outside the arrangement range of the light emitting element row;
A light receiving portion provided corresponding to the second light emitting element and detecting light incident from the outside of the exposure apparatus;
An exposure apparatus. The exposure apparatus according to claim 1 or 2, wherein
An exposure apparatus in which the light receiving unit is configured to detect light reflected from a marker formed in advance on a part to be exposed exposed by the exposure apparatus. An exposure apparatus according to claim 2, wherein
An exposure apparatus having a common optical system that guides light emitted from the plurality of first light emitting elements and light emitted from the second light emitting elements to the outside of the exposure apparatus. An exposure apparatus according to claim 2, wherein
An exposure apparatus in which the second light emitting element and the light receiving unit are respectively arranged at positions on both extended lines in the arrangement direction of the light emitting element rows. The exposure apparatus according to claim 1 or 2, wherein
An exposure apparatus in which a driving circuit for driving the light emitting element and a light receiving portion are made of polysilicon. The exposure apparatus according to claim 1 or 2, wherein
An exposure apparatus in which the light emitting element array and the light receiving unit are formed on the same surface of the same substrate. The exposure apparatus according to claim 7, wherein
An exposure apparatus in which the light emitting element array and the light receiving unit are arranged separately from each other on the surface of the substrate. The exposure apparatus according to claim 1 or 2, wherein
An exposure apparatus in which the light emitting element is composed of an organic electroluminescence element. A light emitting element array composed of a plurality of first light emitting elements;
A second light emitting element provided outside the arrangement range of the light emitting element row;
An exposure unit that is provided corresponding to the second light emitting element and includes a light receiving unit that detects light incident from the outside;
An image carrier on which light scanning in the main scanning direction is performed by the light emitting element array and an image is formed;
Reflected light from a predetermined region at both ends in the main scanning direction of the image carrier by the second light emitting element is detected by the light receiving unit, and the positional relationship between the exposure unit and the image carrier based on the detection result Position updating means for updating
An image forming apparatus. The image forming apparatus according to claim 10, wherein
Markers are formed at both ends in the main scanning direction of the image carrier, and the irradiation light from the exposure unit is irradiated onto the marker to detect the rise or fall time difference of each reflected light from the marker, An image forming apparatus that continues the positional relationship updating operation so as to reduce the time difference. The image forming apparatus according to claim 10, wherein:
An image forming apparatus in which a light emission start timing of the second light emitting element is a predetermined time after the light is turned off after the marker is detected.

Images