JP2015094629A - Detection apparatus, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detection apparatus configured to adjust temperature increase of an optical element with a simple configuration, to prevent detection accuracy from being varied due to heat, thereby increasing detection accuracy, and an image forming method.SOLUTION: A detection apparatus 100 includes: a light source 51; light-receiving means 58 which irradiates an object with light emitted from the light source 51, to detect light reflected from the object; optical elements 55, 57 for capturing an image of the reflected light on the light-receiving means 58; a support section 63 which supports the optical elements 55, 57; and a housing 50 which holds the light source 51, the light-receiving means 58, the optical elements 55, 57, and the support section 63. The support section 63 rotates around an optical axis of the optical elements 55, 57, is asymmetric with respect to the optical axis, and selectively forms a heat passage 73 which is rotated around the optical axis to connect the inside and the outside of the housing 50 each other.

Description

  The present invention relates to a detection device that detects the state of a moving detection object, and an image forming apparatus and an image forming method including the detection device.

2. Description of the Related Art Detection devices that detect a state of a detection target by irradiating a detection light such as a laser onto a moving detection target are known. For example, detection means for detecting surface roughness, distortion, position, or the like using a speckle pattern generated by interference of reflected light that is irradiated from a light source and reflected by a detection target is known. Such a detection means is generally called a speckle sensor. In a speckle sensor, for example, a speckle pattern to be detected is irradiated with detection light from a light source to a detection object, and reflected light from the detection object is imaged on a light receiving means such as a CMOS sensor via an optical element. It is gained in. In such a detection means, it is known that the fluctuation of the detection target can be calculated by tracking the speckle pattern in time, and the result is used for feedback control.
As one form of applying such a speckle pattern detection means to an image forming apparatus, an image carrier, an intermediate transfer belt, or a conveyance belt constituting the conveyance means is a detection object, and the speed of the detection object is determined. It can be considered that the detection is performed with high accuracy to control the image forming position and the paper feed timing.
For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2010-134190), the configuration of the speckle sensor and the obtained temporal time are detected in order to easily and accurately detect the speed fluctuation of the moving medium that is the detection target. A method of detecting the moving speed of the moving medium by performing a cross-correlation operation between different image signals and obtaining a shift of a position where a correlation peak occurs, and a position of an image formed on the moving medium from the acquired image signal A method for detecting a shift and a configuration of a detection apparatus and an image forming apparatus are disclosed.

In such a detection device, there is a problem that variation occurs in detection accuracy due to internal heat generation of the detection device. That is, when the detection device is driven, a plurality of heat sources (such as IC chips) provided in the detection device generate heat. The heat generated by this heat generation is transmitted to the housing of the detection means, and the optical element supported by the housing is decentered and displaced, which affects the optical performance of the entire detection device. In addition, since heat generated by heat generation is transmitted to the optical element, the refractive index of the optical element itself changes, which also affects the optical performance. For this reason, the detection result with desired accuracy cannot be obtained due to the influence of heat.
An object of the present invention is to improve detection accuracy by suppressing variations in detection accuracy due to heat by making it possible to adjust the temperature rise of an optical element with a simple configuration.

  In order to achieve the above object, a detection apparatus according to the present invention includes a light source, a light receiving unit that irradiates the detection target with light emitted from the light source, and detects reflected light from the detection target. An optical element for picking up an image of the optical element, a support part for supporting the optical element, a light source, a light receiving means, an optical element, and a housing for holding the support part. The support part is rotatable about the optical axis of the optical element. The heat flow path has an asymmetric shape with respect to the optical axis, and can be selectively formed as a heat flow path that communicates the inside and the outside of the housing by rotating around the optical axis.

  According to the present invention, since the presence or absence of the heat flow path can be selected by rotating the support portion of the optical element, the heat radiation amount of the housing holding the optical element and the support portion can be changed. The rising temperature can be adjusted with a simple configuration. For this reason, variation in detection accuracy due to heat can be suppressed and detection accuracy can be improved.

1 is a schematic configuration diagram showing an embodiment of an image forming apparatus according to the present invention. FIG. 3 is a schematic configuration diagram showing another embodiment of the image forming apparatus according to the present invention. 1 is a schematic configuration diagram showing an embodiment of an optical scanning device. The schematic diagram which shows the basic composition of the detection apparatus which concerns on this invention. The figure which unfolded and displayed the optical path of the detecting device concerning the present invention. The perspective view which shows the external appearance structure of 1st Embodiment of the detection apparatus which concerns on this invention. FIG. 7 is a perspective cross-sectional view showing a state when a heat channel is formed in the detection device shown in FIG. 6. FIG. 7 is a front sectional view showing a state when a heat channel is formed in the detection device shown in FIG. 6. It is the fragmentary sectional view which looked at the structure of the support part when the heat flow path was formed in the detection apparatus shown in FIG. FIG. 7 is a perspective cross-sectional view showing a state when a heat channel is not formed in the detection device shown in FIG. 6. FIG. 7 is a front cross-sectional view showing a state when a heat channel is not formed in the detection device shown in FIG. 6. It is the fragmentary sectional view which looked at the structure of the support part when a heat flow path is not formed in the detection apparatus shown in FIG. FIG. 7 is a perspective cross-sectional view showing a state where a heat channel is partially formed in the detection device shown in FIG. 6. It is the fragmentary sectional view which looked at the structure of the support part when a heat flow path is partially formed in the detection apparatus shown in FIG. The figure which shows the result of the temperature simulation by the presence or absence of the heat flow path in the detection apparatus shown in FIG. The figure which shows the measurement result of the ultimate temperature of an optical element by the presence or absence of the heat flow path in the detection apparatus shown in FIG. The perspective sectional view showing the composition of a 2nd embodiment of the detecting device concerning the present invention. The perspective sectional view showing the state when the configuration of the second embodiment of the detection device according to the present invention and the heat flow path are formed. The perspective sectional view showing the state when the configuration of the second embodiment of the detection device according to the present invention and the heat flow path are not formed. (A), (B) is the image which irradiated the laser beam to the detection target which has light-scattering property, and image | photographed it with the CMOS camera, (C) is a figure which shows the image pattern after a cross correlation calculation.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
The feature of the detection apparatus according to the present invention is that the support portion that supports the optical element is configured to be rotatable along the optical axis of the optical element, and the support portion has an asymmetric shape with respect to the optical axis. By rotating the support portion around, a heat flow path that communicates the inside and the outside of the housing holding the support portion can be selectively formed.
In short, it is possible to select whether or not to form a heat flow path inside the housing by rotating the support portion. Thereby, in the detection apparatus itself, the amount of heat radiated from the heat source such as the light source or IC to the housing or the optical element can be adjusted. Thereby, the performance change due to the temperature rise of the optical element and the movement amount of the optical element due to the thermal expansion of the housing or the like can be offset as much as possible.

A basic configuration of the image forming apparatus according to the present embodiment will be described and an outline thereof will be described with reference to FIGS.
FIG. 1 shows a basic configuration example of an intermediate transfer type image forming apparatus according to the present invention. In addition, in each figure and each embodiment, the same member or a member having the same function is basically denoted by the same reference numeral, and redundant description is appropriately omitted.
This image forming apparatus is capable of forming full-color images, arbitrary single-color images, and multi-color images using yellow (Y), magenta (M), cyan (C), and black (K) developers. . Hereinafter, the members corresponding to the respective colors will be distinguished by attaching Y, M, C, and K subscripts, respectively.
The image forming apparatus includes a transfer device 20 including an intermediate transfer belt 105 as an intermediate transfer member, drum-shaped photoreceptors 1Y, 1M, 1C, and 1K as image carriers, an optical scanning device 20, and a fixing unit 30. And a control means 200 functioning as a speed adjustment means.
The photoreceptors 1Y, 1M, 1C, and 1K are rotationally driven by a driving unit (not shown) in the direction of the arrow (counterclockwise direction) in the drawing. The photoconductors 1Y, 1M, 1C, and 1K are juxtaposed along the intermediate transfer belt 105 to form a tandem image forming unit. Around the photoreceptors 1Y, 1M, 1C, and 1K, charging units 2Y, 2M, 2C, and 2K as charging units, developing units 4Y, 4M, 4C, and 4K as developing devices, and primary transfer units 6Y, 6M, and 6C , 6K, and photoconductor cleaning means 5Y, 5M, 5C, 5K, and the like, respectively.
As the chargers 2Y, 2M, 2C, and 2K, a contact type using a charging roller is shown in FIG. 1, but a charging brush, a non-contact type corona charger, or the like can also be used. As the primary transfer means 6Y, 6M, 6C, 6K, a known transfer charger, transfer roller, transfer brush, or the like can be used. In the figure, reference numeral 30 denotes a fixing unit, 40 denotes a secondary transfer unit, and 41 denotes a conveying unit.

The photoconductors 1Y, 1M, 1C, and 1K are uniformly charged by the chargers 2Y, 2M, 2C, and 2K, and then light beams that are intensity-modulated according to image information by the optical scanning device 20 that is a latent image forming unit. (For example, a laser beam) is exposed to form an electrostatic latent image. The basic configuration of the optical scanning device 20 that performs this exposure process will be described later.
The electrostatic latent images formed on the photoconductive drums 1Y, 1M, 1C, and 1K are developed by the developing unit 114Y, the developing unit 114M, the developing unit 114C, and the developing unit 114K, respectively, and each color of yellow, magenta, cyan, and black is developed. Developed as a toner image.
The toner images on the photoreceptors 1Y, 1M, 1C, and 1K that have been visualized in the above development process are sequentially superimposed and sequentially transferred onto the intermediate transfer belt 105. Then, the toner images of the respective colors superimposed on the intermediate transfer belt 105 are fed from a paper feeding unit (not shown), and are recorded on the paper or the like that has been conveyed to the position of the secondary transfer unit 40 via a conveyance unit (not shown). Secondary transfer is performed collectively on the medium S. The recording medium S to which the toner image has been transferred is conveyed to the fixing unit 30 by a conveyance unit 41 such as a conveyance belt, and the toner image is fixed by the fixing unit 30, thereby obtaining a multicolor image or a full color image. The recording medium S after fixing is discharged to a paper discharge unit, a post-processing device, etc. (not shown).

The photoreceptors 1Y, 1M, 1C, and 1K after the toner image transfer are cleaned by cleaning members (blades, brushes, and the like) of the cleaning units 5Y, 5M, 5C, and 5K to remove residual toner. The intermediate transfer belt 105 after the toner image transfer is also cleaned by a belt cleaning unit (not shown) to remove residual toner.
In the image forming apparatus shown in FIG. 1, a single color mode for forming an image of any one color of yellow, magenta, cyan, and black, and an image of any two colors of yellow, magenta, cyan, and black are formed in an overlapping manner. There are two-color mode, three-color mode in which images of three colors of yellow, magenta, cyan, and black are superimposed and a full-color mode in which four-color superimposed images are formed as described above. It is possible to form single-color, multi-color, and full-color images by specifying and executing them on the operation unit.

In the case of full-color printing, the image forming apparatus shown in FIG. 1 uses an intermediate transfer belt 105 to perform primary transfer from the photoreceptors 1Y, 1M, 1C, and 1K to the intermediate transfer belt 105 to form an overlapping image of each color. Although an intermediate transfer system that performs secondary transfer collectively from the intermediate transfer belt 105 to a recording medium S such as paper, the image forming apparatus is not limited to such an intermediate transfer system.
For example, as shown in FIG. 2, instead of the intermediate transfer belt, a conveying belt 106 that carries and conveys a recording medium S such as paper is disposed opposite to the photosensitive drums 1Y, 1M, 1C, and 1K, and transferred between the two. The image forming apparatus may be of a type in which a portion is formed and transferred directly from the photosensitive drums 1Y, 1M, 1C, and 1K to the recording medium S. The detection means according to the present invention can be applied to these image forming apparatuses.

In the direct transfer type image forming apparatus shown in FIG. 2, the approach path of the recording medium S is different from that in FIG. 1, and the recording medium S is conveyed toward the photosensitive drums 1Y, 1M, 1C, and 1K by the conveying belt 106. It is supposed to be.
In this image forming apparatus, similarly to the above, the photoreceptors 1Y, 1M, 1C, and 1K are uniformly charged by the chargers 2Y, 2M, 2C, and 2K, and then image information is obtained by the optical scanning device 20 that is a latent image forming unit. A light beam (for example, laser light) whose intensity is modulated in accordance with the exposure is exposed to form an electrostatic latent image. The electrostatic latent images formed on the photoconductive drums 1Y, 1M, 1C, and 1K are developed by the developing unit 114Y, the developing unit 114M, the developing unit 114C, and the developing unit 114K, and toners of yellow, magenta, cyan, and black colors. Visualized as an image.

  Then, the recording medium S is fed from a paper feeding unit (not shown) at the same timing as the developing process, conveyed to the conveying belt 106 via a conveying means (not shown), and carried on the conveying belt 106. The recording medium S carried on the conveyance belt 106 is conveyed toward the photosensitive drums 1Y, 1M, 1C, and 1K. Then, the toner images on the photoreceptors 1Y, 1M, 1C, and 1K developed and visualized in the above developing process are sequentially superimposed and transferred onto the recording medium S by the transfer units 6Y, 6M, 6C, and 6K. The The four-color superimposed toner image transferred onto the recording medium S is conveyed to the fixing unit 30, and the toner image is fixed on the recording medium S by the fixing unit 30 to obtain a multicolor or full-color image. The recording medium S after fixing is discharged to a paper discharge unit, a post-processing device, or the like (not shown). The photoreceptors 1Y, 1M, 1C, and 1K after the toner image transfer are cleaned by cleaning members (blades, brushes, and the like) of the cleaning units 5Y, 5M, 5C, and 5K to remove residual toner.

Next, the optical scanning device 20 will be described.
FIG. 3 is a schematic configuration diagram illustrating an embodiment of an optical scanning device provided in each of the image forming apparatuses. 3, four photosensitive drums 301, 302, 303, and 304 (corresponding to the photosensitive members 1Y, 1M, 1C, and 1K in FIG. 1 or 2) are transferred to a transfer belt 400 (the intermediate transfer belt 105 in FIG. 2 or FIG. 2). In the image forming apparatus that forms a color image by sequentially transferring toner images of different colors, the optical scanning devices are integrally configured as a single unit. All light beams are scanned by the rotating light deflecting means (for example, polygon mirror) 1050. The polygon mirror 1050 has six surfaces and has a two-stage structure.
More specifically, the optical scanning device 20 includes a light source unit 1001, a single polygon mirror 1050 that deflects and scans a light beam from the light source unit 1001, and a scanning beam scanned by the polygon mirror 1050. Scanning lenses 1061 and 1062 that form an image on the surface to be scanned of the drum 302 are provided. Here, the optical scanning device 20 scans by two stations in a direction facing the polygon mirror 1050. In FIG. 3, for simplification of explanation, three light source units for scanning the other photosensitive drums 301, 303, and 304 and the optical system after the scanning lens are omitted, and only one station is illustrated. ing.

The light source unit 1001 includes a light source (for example, a semiconductor laser (LD), an LD array, etc.), a coupling lens, and an aperture. A light beam emitted from a light source (not shown) of the light source unit 1001 is converted into a substantially parallel light, a substantially divergent light beam, or a substantially convergent light beam by a coupling lens (not shown), and then cut into a desired light beam width by an aperture (not shown). A linear image forming lens (for example, a cylindrical lens) 1041 condenses once in the sub-scanning direction in the vicinity of the polygon mirror 1050, and a beam spot is formed on the image plane (scanned surface) 2001 by the scanning optical system including the scanning lenses L1: 1061. Form.
As described above, the normal optical scanning device 20 employs a surface tilt correction optical system that once collects light in the sub-scanning direction in the vicinity of the polygon mirror in order to reduce deterioration of optical characteristics due to surface tilt between the mirrors of the polygon mirror 1050. Has been.

The scanning lens is made of resin, and the diffraction grating may be formed on one or a plurality of optical surfaces. Folding mirrors 1111 and 1121 are inserted between the polygon mirror 1050 and the image plane, and the optical path is folded. Although the embodiment in which the scanning optical system is composed of one scanning lens is shown, two or more scanning lenses may be used.
Here, a writing start position correcting unit (for example, a liquid crystal deflecting element) for correcting a writing start position by the optical scanning device 20 is preferably provided between the coupling lens of the light source unit 1001 and the cylindrical lens 1041.
In the case of the intermediate transfer type image forming apparatus shown in FIG. 1, the intermediate transfer belt 105 is used. In the case of the direct transfer type image forming apparatus shown in FIG. Deviation occurs.
In order to drive these belts with high accuracy, a method of making all the component parts with high accuracy is conceivable, but there are many component parts, and it is difficult to realize in reality from the viewpoint of cost. Therefore, it is preferable to provide detection means for detecting the speed fluctuation of each belt, and feed back the detection result to the drive motor 90 that rotationally drives each belt. For this purpose, speed detecting means for detecting speed fluctuations of the intermediate transfer belt 105 and the conveying belt 106 is required. In order to detect the speed fluctuation of each belt, the mark was formed directly on the belt in the past. However, it is difficult to process the belt directly, and it takes time to process. It becomes a factor of.

Therefore, in this embodiment, without directly processing the intermediate transfer belt 105 and the conveyance belt 106, the speed variation of each belt as a detection target portion is easily detected, and the toner image pattern formed on each belt is detected. The detection apparatus 100 capable of simultaneously detecting the positional deviation and the image density is used.
That is, the image forming apparatus shown in FIGS. 1 and 2 includes a detection unit 100 that detects movement information of the intermediate transfer belt 105 and the conveyance belt 106, and a speed adjustment unit that adjusts the movement speed of the intermediate transfer belt 105 and the conveyance belt 106. The control means 200 is provided. The control means 200 is composed of a computer and performs foot-back control on the rotational speed of the drive motor 90 that rotationally drives each belt based on the moving speed information of each belt that is the detection result detected by the detection means 100. Is.

  The optical scanning device 20 includes a position adjustment device 300 that individually adjusts the incident positions of light on the photosensitive drums 301, 302, 303, and 304 in the sub-scanning direction. The position adjusting device 300 individually adjusts the incident position of light on the photosensitive drums 301, 302, 303, and 304 based on the detection result of the detecting device 100. For this reason, the position adjusting device 300 is connected to the control means 200 via a signal line, and the incident position of light on the photosensitive drums 301, 302, 303, 304 is controlled based on the detection result of the detecting device 100. It is foot-back controlled by means 200.

  A basic configuration example of the detection apparatus 100 will be described with reference to FIG. The detection apparatus 100 has a function of detecting the formation position deviation of the toner image pattern formed on the moving member 53 and the image density in parallel with the detection of the moving speed of the moving member 53 serving as a detection target. Yes.

Regarding speed detection, the speed and speed fluctuation of the moving member 53 (endless belt-like member such as an intermediate transfer belt and a conveyance belt, or drum-like member, or a recording medium such as paper) 53 are detected.
The detection apparatus 100 includes a laser light source 51 as a light source that emits laser light that is coherent light, a collimator lens 52 as an optical element that makes the laser light emitted from the laser light source substantially parallel, and a one-dimensional or An area sensor 58 as a light receiving means (for example, a light receiving element array) capable of acquiring a two-dimensional image, and an imaging lens (hereinafter referred to as an optical element) provided between the aperture stops 54 and 56 and the moving member 53 and the area sensor 58. , Simply referred to as “lens”) 55 and 57. The lens 55 and the lens 57 are arranged on the same optical axis, and the area sensor 58 is arranged so that the center thereof is located on the optical axis.

  The detection device 100 emits laser light emitted from the laser light source 51 and made substantially parallel light by the collimator lens 52 obliquely to the moving member 53, and is one-dimensional from the direction perpendicular to the moving plane of the moving member 53. Alternatively, the image is taken by the two-dimensional area sensor 58. The moving member 53 is a member having light diffusibility on the surface or inside thereof, and when irradiated with laser light, diffused reflected light having a distribution indicated by reference numeral 59 is reflected. When a part of such diffuse reflected light is taken from the lens 55 and imaged on the area sensor 58 via the lens 57, a random image pattern called a speckle pattern by the diffused laser light is obtained. This speckle pattern is a pattern corresponding to a fine random uneven shape on the surface or inside of the moving member 53, and is formed by random interference of laser light.

  When the moving member 53 moves, the speckle pattern also moves. As a feature of the speckle pattern, the speckle pattern is not lost even when the imaging position is moved back and forth in the optical axis direction of the lenses 55 and 57, so that the surface of the moving member 53 or the uneven shape on the inside is very stable. A corresponding speckle pattern can be obtained. Therefore, normally, the lenses 55 and 57 between the area sensor 58 and the moving member 53 are not necessary. However, when the moving member 53 is inclined with respect to the moving plane due to some disturbance, the speckle pattern changes on the area sensor 58, and a detection error occurs when detecting a speed change described later. May occur. Therefore, in order to avoid this problem, it is possible to arrange lenses 55 and 57 between the area sensor 58 and the moving member 53 so that the moving member 53 and the area sensor 58 have a conjugate relationship of imaging. desirable. As a result, even if the moving member 53 is inclined with respect to the moving plane, the change in the speckle pattern on the area sensor 58 can be reduced, and the speed detection error can be reduced.

The lens 55 and the lens 57 are preferably set so that the moving member 53 and the area sensor 58 have a conjugate relationship of image formation, but the present invention is not limited to this. There is an effect of reducing the change amount of the speckle pattern due to the inclination of the member 53. Therefore, if the inclination generated in the moving member 53 is not so large, even if it is shifted from the conjugate relationship, it can be suppressed to a practically sufficient speed detection error.
Further, it is desirable that the lens 55 and the lens 57 are used at an image forming magnification that reduces the image of the moving member 53 on the area sensor 58. By doing so, the wide range on the moving member 53 can be reduced on the area sensor 58, and the area sensor 58 can be reduced in size. Further, by using a reduction optical system, the moving speed of the speckle pattern on the area sensor 58 can be reduced even when the moving speed of the moving member 53 is high. If the moving speed on the area sensor 58 is low, the time interval for acquiring the speckle pattern can be lengthened. As a result, it is possible to increase the time for the arithmetic processing and cope with the high-speed movement of the moving member 53. Because it becomes. In addition, the processing speed of the electronic circuit can be reduced, which leads to lower power consumption and cost, which is preferable.
In this embodiment, the collimating lens 52 illuminates the moving member 53 by making the laser light substantially parallel light. However, the moving member 53 is not limited to this, and the moving member is made by converting the laser light into focused light or divergent light depending on the arrangement of the collimating lens. 53 may be illuminated.

  The aperture stops 54 and 56 in FIG. 4 greatly affect the size of the minimum diameter of the speckle pattern on the area sensor 58. When detecting the speckle pattern, it is desirable that the minimum diameter of the speckle pattern on the area sensor 58 is an appropriate size with respect to the size of one pixel of the area sensor. The minimum diameter of the speckle pattern on the area sensor 58 is directly proportional to the light source wavelength and inversely proportional to the angle at which the pupils of the lenses 55 and 57 are viewed. In the present embodiment, the pupil diameters of the lenses 55 and 57 are optimized by the aperture stops 54 and 56 so that the minimum diameter of the speckle pattern is optimized with the size of one pixel of the area sensor 58.

In order to detect the moving speed of the moving member 53 from a one-dimensional or two-dimensional image acquired by the area sensor 58, a cross-correlation function between two speckle images (speckle patterns) acquired at a time interval τ is calculated. Then, the speckle pattern positional deviation amount Δ at the time interval τ is obtained from the position where the cross-correlation peak occurs.
From the above time interval τ and peak position deviation amount Δ,
The moving speed v of the moving member 53 is obtained as v = KΔ / τ.
Here, K is a proportional constant, which is determined from the optical arrangement such as the position of the laser light source and the lens, and this K needs to be obtained in advance.
The calculation of the cross-correlation function between the two speckle images is performed by the following equation.
Here, let two speckle images be f1 and f2.
Further, Fourier transform is F [], inverse Fourier transform is F ^-1 [], symbol ★ indicates a cross-correlation operation, and ^* indicates phase conjugation.
f1 * f2 ^* = F ⁻¹ [F [f1] · F [f2] ^* ] f1 * f2 ^* is image data after the cross-correlation calculation. If f1 and f2 are two-dimensional images, two-dimensional, f1, If f2 is a one-dimensional image, it is one-dimensional data.
In the image data of f1 * f2 ^* , the position of the steepest peak (correlation peak) intensity represents the amount of displacement between the two speckle images. Therefore, the amount of movement between the two speckle images can be calculated by searching for the steepest peak.

Since the above-described cross-correlation calculation method can use fast Fourier transform, the amount of positional deviation Δ between speckle patterns can be detected with a relatively small amount of calculation and with high accuracy. Therefore, since the positional deviation amount Δ and the time difference τ between the two speckle images are known, the moving speed v of the moving member 53 can be calculated.
In FIG. 4, the moving direction of the moving member 53 is shown from the left to the right in FIG. 4, but the present invention is not limited to this, and the moving member 53 moves in any direction in the plane. The same applies to the case.

20A and 20B are obtained by irradiating a detection target (moving member) having light scattering properties with a laser beam and photographing it with a CMOS camera. 20A is before the detection object (moving member) moves, and FIG. 20B is after the detection object (moving member) is moved to the right by 100 μm. In FIG. 20, a lens is disposed in front of the CMOS camera, and the object surface and the CMOS surface are substantially conjugated. In addition, since the photographing magnification is set to 1, the amount of displacement between the two speckle patterns calculated from the position of the correlation peak matches the amount of movement of the detection target (moving member).
FIG. 20C shows an image pattern after the cross-correlation calculation, and a steep correlation peak exists in the broad intensity distribution. Although this correlation peak is not buried in the broad intensity distribution, the peak of the broad intensity distribution may be higher, so it is important to search for the steepest peak position.

FIG. 5 shows an optical path diagram of the detection apparatus 100. Although the optical path of the detection apparatus 100 is originally bent at the surface to be measured of the moving member 53, it is described here as being developed. Based on FIG. 5, a detection error is obtained.
The amount of movement Y on the detection of the area sensor (image sensor) 58 and the amount of movement Y ′ on the area sensor (image sensor) 58 after displacement are obtained from the following equation (1). V is the velocity on the imaging surface of the area sensor (image sensor) 58, V ′ is the velocity on the imaging surface after displacement, v is the velocity on the paper surface (test surface), t is the measurement time, ΔY indicates a detection error.
Y ′ = V ′ × t = Y + ΔY, Y = V × t Expression (1)
From equation (1), the detection error ΔY is:
ΔY = Y × ((V ′ / V) −1) (2)
V is obtained by equation (3). M is an imaging magnification between the Gaussian image plane and the imaging plane, Db is a distance between the Gaussian image plane and the boiling plane, and D is a distance between the Gaussian image plane and the imaging plane.
V = M * ((D / Db) -1) * v ... Formula (3)

(First embodiment)
Next, a specific embodiment of the detection apparatus 100 and an adjustment operation of a heat flow path that functions as a cooling unit will be described with reference to FIGS.
6 is a perspective view showing an external configuration of the detection apparatus 100, FIGS. 7 to 9 are cross-sectional views when a heat flow path is formed in the detection apparatus 100, and FIGS. 10 to 12 are views of the heat flow path in the detection apparatus 100. FIG. FIG. 13 and FIG. 14 are cross-sectional views when a heat flow path is partially formed in the detection device 100. FIG.
As shown in FIG. 6, the detection device 100 has an outer appearance and includes a housing 50 that houses components. The housing 50 is made of resin and is divided into a light emitting block 50A and a light receiving block 50B. In FIG. 6, a substrate 61 having an IC chip 70 serving as a heat source is mounted below the housing 50. The IC chip 70 is disposed on one surface 61 b of the substrate 61. The lens 57 is disposed on the other surface 61 a side of the substrate 61 and is disposed on the opposite side of the IC chip 70 with the substrate 61 interposed therebetween. The substrate 61 includes an image processing circuit 75.

An irradiation tube portion 50C is formed in the light emitting block 50A. As shown in FIGS. 7 to 14, a laser light source 51 and a collimating lens 52 are disposed in the irradiation tube portion 50C. In the light receiving block 50B, aperture stops 54 and 56, lenses 55 and 57, and an area sensor 58 are arranged.
In the light receiving block 50B, a cylindrical storage portion 50D is formed so as to extend in the height direction H of the light receiving block 50B. An opening 50E is formed at the end on the entrance side of the storage 50D. At the end opposite to the opening 50E, the image sensor 58 is mounted on the surface 61a of the substrate 61 so as to be positioned in the storage portion 50D. The support portion 60 is rotatably stored in the storage portion 50D. The support unit 60 includes support members 63 and 64, a cylindrical rotating member 65, and a cylindrical spacer 66, which are a plurality of members, and each member is arranged coaxially. The storage portion 50D is configured such that after the support members 63 and 64, the rotating member 65, and the spacer 66 are stored, a ring-shaped cover 62 is attached to the opening 50E and the support portion 60 is not detached from the storage portion 50D. Has been. In the present embodiment, the height direction H is the optical axis direction.

The support member 63 has a substantially cylindrical shape extending in the height direction (optical axis direction) H, and is mounted so as to be covered on the outside of the support member 64. A protrusion 63 </ b> A is formed at one end of the support member 63. A through hole 63B that forms a part of the optical path is formed in the protrusion 63A and the support member 63. A lens 55 is supported and held inside the protrusion 63A that is an end of the through hole 63B. The through hole 63B located at the end of the protrusion 63A rather than the lens 55 functions as the aperture stop 54. The outer diameter of the support member 63 is substantially the same as the inner diameter of the storage portion 50D, and is rotatably attached to the storage portion 50D.
The support member 64 extends in the height direction (optical axis direction) H and has the same length as the storage portion 50D. The support member 64 includes a cylindrical large-diameter portion 64A and a cylindrical small-diameter portion 64B, and an aperture stop 56 is formed in a space portion 64A1 formed inside the large-diameter portion 64A. In the small diameter portion 64B located between the aperture stop 56 and the area sensor 58, a through hole 64B1 that penetrates the support member 64 in the height direction (optical axis direction) H and constitutes a part of the optical path is formed. Yes. A lens 57 is supported and held inside the through hole 64. The support member 63 and the support member 64 are configured as separate members so that the distance in the height direction (optical axis direction) H of the lens 55 and the lens 57 can be adjusted, and are provided so as to be relatively rotatable. . That is, the support member 63 is put on the outer peripheral surface 64 a of the support member 64 and is rotatable. If the distance between the lens 55 and the lens 57 in the height direction (optical axis direction) H is not adjustable, the lens 55 and the lens 57 may be configured integrally.

The spacer 66 is a cylindrical member extending in the height direction (optical axis direction) H, and is disposed in the storage portion 50 </ b> D so as to be interposed between the area sensor 58 and the support member 63. The spacer 66 accommodates the rotating member 65 in a rotatable manner. The inner diameter of the spacer 66 is substantially the same as the outer diameter of the rotating member 65 and the large-diameter portion 64A of the support member 64, and rotatably supports the large-diameter portion 64A of the rotating member 65 and the support member 64. The end portion 66 b of the support member 63 can be placed on the end portion 66 b of the spacer 66. Therefore, the distance (focal length) between the lens 55 and the lens 57 and between the lens 55 and the area sensor 58 can be adjusted by changing the length of the spacer 66 in the height direction (optical axis direction) H. Has been.
The rotating member 65 housed in the spacer 66 is a cylindrical member extending in the height direction (optical axis direction) H, and the outer diameter of the small-diameter portion 64B of the support member 64 and the inner diameter are substantially the same. It is formed in the same dimension and supports the small diameter portion 64B in a rotatable manner. An end portion 64 </ b> Aa of the large-diameter portion 64 </ b> A of the support member 64 can be placed on the end portion 65 b of the rotating member 65. Therefore, the distance between the lens 55 and the lens 57 and the distance between the lens 57 and the area sensor 58 can be adjusted by changing the length of the rotating member 65 in the height direction (optical axis direction) H. .

  Slits 67A, 67B, and 67C extending in the height direction (optical axis direction) H are formed on the outer peripheral surfaces 63a, 65a, and 66a of the support member 63, the rotation member 65, and the spacer 66, respectively. The slits 67A, 67B, 67C are formed to have the same width in the circumferential direction, for example, and by rotating the support member 63, the rotation member 65, and the spacer 66 integrally or individually, the height direction (optical axis direction) ) In H, they can be arranged in communication on the same line (straight line). Since the support member 63, the rotation member 65, and the spacer 66 are configured to be rotatable with respect to each other, all the slits 67A, 67B, 67C, the slit 67A and the slit 67B, the slit 67A and the slip 67C, or the slit 67B and the slit 67C are included. The communication state is configured to be adjustable by rotating to communicate.

In the storage portion 50D, openings 71 and 72 that communicate between the inside of the storage portion 50D (inside the housing) and the outside of the housing are formed at an interval in the height direction (optical axis direction) H. The opening 71 is configured to communicate with the slit 67A when the support member 63 is rotated and the slit 67A occupies a position facing the opening 71. The opening 72 is configured to communicate with the slit 67C when the spacer 66 is rotated and the slit 67C occupies a position facing the opening 72.
As described above, the support member 63, the rotation member 65, and the spacer 66 are rotated so that the slits 67A, 67B, and 67C are arranged on the same line (straight line) so as to communicate the opening 71 and the opening 72. Thus, as shown in FIGS. 7 to 9, the heat flow path 73 is formed in the storage portion 50 </ b> D. 10 to 12, the slits 67A, 67B, and 67C are arranged on the same line (straight line), but the opening 71 and the opening 72 are arranged on the opposite side. Not formed. In FIGS. 13 and 14, the slits 67B and 67C are arranged on the same line (straight line), the slit 67C communicates with the opening 72, and the slit 67A is arranged on the opposite side to the opening 71. , 67C and the opening 72 form a heat flow path 73.

In the storage portion 50D, the spacer 66, the rotation member 65, the support member 64, and the support member 63 are dropped and stored in this order, and are rotatably held. Of course, after assembling these members in advance, they may be stored in the storage section 50D and held rotatably. A coil spring 69 as an urging unit is interposed between the end of the support member 63 stored and held in the storage unit 50D and the cover 62, and includes a spacer 66, a rotation member 65, a support member 64, and a support. The member 63 is biased toward the area sensor 58 side to perform positioning in the height direction (optical axis direction) H.
In the present embodiment, since the reflected light is incident on the area sensor 58 from the opening 50E side of the storage portion 50D, the rotation center axes of the spacer 66, the rotation member 65, the support member 64, and the support member 63 are the lenses 55 and 57. It is comprised so that it may be parallel to the optical axis of this, and may be located on the same axis as an optical axis.

The detection device 100 configured as a speckle sensor according to the present embodiment irradiates the moving light 53 with the laser light source 51 that emits coherent light and the light emitted from the laser light source 51, and reflects the reflected light from the moving member 53. The area sensor 58 to be detected, the lenses 55 and 57 that capture the speckle pattern image of the reflected light on the area sensor 58, the support unit 60 that supports the lenses 55 and 57, and the movement of the moving member 53 vary with time. The movement speed of the moving member 53 is obtained by acquiring an image of a speckle pattern, performing a cross-correlation operation between the acquired images of speckle patterns different in time, and obtaining a shift of a position where a correlation peak of the cross-correlation operation occurs. An image processing circuit 75 for deriving the image and a housing 50 for holding these members, and the support portion 60 rotates around the optical axis of the lens 55. And is formed in an asymmetric shape with respect to the optical axis, and is provided so that a heat flow path 73 that communicates the inside and the outside of the housing 50 can be selectively formed by rotating around the optical axis. Yes.
The support unit 60 includes support members 63 and 64 arranged in the optical axis direction, a rotation member 65, and a spacer 66. At least one member can rotate around the optical axis, and the heat flow path 73 is formed. Slits 67A, 67B, and 67C to be formed are formed.
That is, the detection method by the detection apparatus 100 configured as the speckle sensor according to the present embodiment irradiates the moving member 53 with the laser light source 51 that emits coherent light and the light emitted from the laser light source 51. Sensor 58 that detects the reflected light from the lens, lenses 55 and 57 that capture an image of the speckle pattern of the reflected light on the area sensor 58, a support portion 60 that supports the lenses 55 and 57, and movement of the moving member 53 At the same time, acquire images of speckle patterns that are temporally different, perform cross-correlation between the acquired images of speckle patterns that are different in time, and determine the shift of the position where the correlation peak of the cross-correlation calculation occurs. An image processing circuit 75 for deriving the moving speed of the member 53 and a housing 50 for holding these members are provided. The heat flow path 73 that is rotatable around the optical axis 55 and is formed in an asymmetric shape with respect to the optical axis and that communicates between the inside and the outside of the housing 50 by rotating around the optical axis is selectively used. Is formed.

In the detection apparatus 100 having such a configuration, the support member 63, the rotation member 65, and the spacer 66 are rotated, so that all the slits 67A to 67C are on the same line (straight line) as shown in FIGS. And the heat flow path 73 is formed by communicating with the openings 71 and 72. Due to the temperature difference of the housing 50, the outside air is sucked into the storage portion 50 </ b> D from either the opening 71 or the opening 72, passes through the slits 67 </ b> A to 67 </ b> C, and is discharged from either the opening 72 or the opening 71. . That is, one of the opening 71 and the opening 72 serves as an inlet and the other serves as an outlet. Which is the suction port varies depending on the heating state of the storage portion 50D (housing 50).
When the heat flow path 73 is formed in this way, an air flow is generated due to a temperature difference in the height direction (optical axis direction) H of the housing 50, and the heat dissipation performance of the housing 50, particularly the heat dissipation performance of the housing portion 50D, can be improved. The temperature of the storage unit 50D can be reduced. As a result, even when the temperature of the lenses 55 and 57 exceeds the design range, the temperature rise of the lenses 55 and 57 can be suppressed by rotating the support portion 60 so as to form the heat flow path 73. The variation in detection accuracy due to can be suppressed, and the detection accuracy can be increased.
Further, when the temperature of the housing 50 and the lenses 55 and 57 is within the design range, there is no need to cool the slits 67A to 67C, so that the slits 67A to 67C communicate with the openings 71 and 72 as shown in FIGS. Thus, the support member 63, the rotation member 65, and the spacer 66 may be rotated so that the heat flow path 73 is not formed.

  In the present embodiment, the positions of the slits 67A to 67C in the rotation direction can be arbitrarily changed by changing the positions of the support member 63, the rotation member 65, and the spacer 66 in the rotation direction. it can. For this reason, depending on the temperature of the lenses 55 and 57, as shown in FIGS. 13 and 14, for example, the slits 67B and 67C may be in a communicating state so as to face the opening 72 and be in an intermediate state where the outside air is released to the opening 71. .

  Thus, in the detection means 100, since the presence or absence of the heat flow path 73 can be selected by rotating the support portion 60 of the lenses 55 and 57 that are optical elements, the heat radiation amount can be changed, and the lens 55 , 57 can be selectively adjusted with a simple configuration. For this reason, the optical performance can be adjusted / optimized arbitrarily even after the detection apparatus 100 is manufactured, so that it is possible to enhance the ability to cope with the use environment and the installation environment, and to expand the use range.

  In this embodiment, the support members 63, the rotation member 65, and the spacer 66 that constitute the support portion 60 are independently rotated, and the rotation positions (rotation angles) are individually adjusted, so that the slits 67A to 67C communicate with each other. That is, since the width, number, and location of the heat flow path 73 can be changed, the heat radiation amount of the housing 50 (housing portion 50D) can be adjusted more finely. As a result, the temperature change of the lenses 55 and 57 can be adjusted in more detail.

FIGS. 15A and 15B are diagrams showing the results of temperature simulation with and without the heat flow path 73 in the detection apparatus 100. FIG. 15A and 15B show a model of the detection apparatus 100 created using CAD software of a computer, and the model is simulated for temperature distribution by designating a heat source using thermal analysis software. It is. FIG. 15A shows the temperature distribution when there is a heat flow path 73, and FIG. 15B shows the temperature distribution when there is no heat flow path 73.
In FIG. 15B, since the heat flow path 73 is not formed, the temperature in the vicinity of the housing portion 50D of the housing 50 housing the support portion 60 is relatively high due to the heat generated by the heat source. . On the other hand, in FIG. 15A, the temperature in the vicinity of the housing portion 50D of the housing 50 housing the support portion 60 is lower than that in FIG. 15B. This is presumed that the formation of the heat flow path 73 introduces and passes outside air into the interior of the heat flow path 73, thereby improving the heat dissipation of the storage section 50D and lowering the temperature. That is, it is presumed that the formation of the heat flow path 73 reduces the temperature due to an increase in the area for heat radiation to the outside air.

FIG. 16 shows the measurement results of the temperatures of the lenses 55 and 57 with and without the heat flow path 73 in the detection apparatus 100. The measurement result is a simulation result measured on computer software. As temperature conditions of the computer software, the reference temperature was set to 25 ° C. as the measurement environment temperature, and the temperature rising from the reference temperature of each lens 55 and 57 at that time was measured.
The state of FIG. 15A shows a case where the heat flow path 73 is formed by connecting all the slits 67A to 67C shown in FIGS. 7 to 9 and communicating with the openings 71 and 72. The state shown in FIG. 15B is when all the slits 67A to 67C shown in FIGS. 10 to 12 are communicated but not communicated with the openings 71 and 72, and the heat flow path 73 is not formed. Indicates.
From the measurement results, the temperature of the lenses 55 and 57 can be reduced by about 3.7 ° C. when the heat channel 73 is present, compared to when the heat channel 73 is not present. The reason why the temperature zone of the lens 55 is lower than that of the lens 57 is that the lens 55 is located closer to the opening 50E located on the incident side of the housing portion 50D and at a position away from the IC chip 70 that is a heat generating portion. .

In the intermediate state where some of the slits shown in FIGS. 13 and 14 communicate with the openings 71 and 72, the lens 55 is more effective than the case where the heat flow path 73 is formed as shown in FIGS. 57, the temperature drop is considered to be small, but it is assumed that the temperature of the lenses 55 and 57 is reduced as compared with the case without the heat flow path 73, and the effect of the heat flow path 73 is considered to be obtained. That is, when the heat flow path 73 is formed in the housing 50, it is presumed that the temperature of the lenses 55 and 57 has decreased due to an increase in the area for releasing heat to the outside air due to the formation of the heat flow path 37. The
Thus, by adjusting the temperature of the lenses 55 and 57, it becomes possible to adjust the fluctuation of the focal length of both, and from FIG. 5, the change of the focal length corresponds to the change of Db. For this reason, the change in Db from the above-described equations (1) and (3) is related to the speed V and the movement amount Y. That is, adjusting the temperature of the lens is equivalent to adjusting the optical performance of the detection device (speckle sensor) 100.

In the present embodiment, the widths of the slits 67A to 67C have been described as the same width, but the width in the rotation direction may be different. In the present embodiment, the slits 67A to 67C are formed linearly, but may be formed in a curved line, a spiral, or a stepped shape.
Further, in the present embodiment, the support member 63, the rotation member 65, and the spacer 66 are provided so that the width, number, and location of the heat flow path 73 can be changed, and the slits 67A, 67B, and 67C are respectively formed. When the spacer 66 and the spacer 66 are integrated, the slits 67A and 67C are formed as one slit. For this reason, the variation of the heat flow path 73 to be formed is smaller than that in the case of individually rotating the support member 63, the rotation member 65, and the spacer 66, but the temperature of the lenses 55 and 57 can be reduced, and the configuration It is preferable because simplification can be achieved.

(Second Embodiment)
In the first embodiment, the storage portion 50D and the support portion 60 are cylindrical members having a circular cross section and are freely rotatable in the circumferential direction. However, the circumferential direction of each member of the support portion 60 by vibration or the like It is assumed that the position at is shifted.
Therefore, as shown in FIGS. 17, 18, and 19, the detection apparatus 100 ′ according to the second embodiment includes support members 63 ′, 64 ′, and a support member 63 ′, 64 ′, The rotating member 65 ′ and the spacer 66 ′ are formed in a rectangular parallelepiped shape which is one of polygonal shapes. The storage portion 50D may be cylindrical, but the cross-sectional shape viewed from the opening 50E side may be formed in a square shape. FIG. 17 is an exploded perspective view of the configuration of the detection apparatus 100 ′, FIG. 18 shows a state where the heat flow path 73 is formed, and FIG. 19 shows a state where the heat flow path 73 is not formed.

Even in the case of this embodiment, slits 67A, 67B, 67C are formed on at least one surface of the support member 63 ′, the rotation member 65 ′, and the spacer 66 ′, respectively. It is formed so as to have an asymmetric shape.
The polygonal shape is not limited to a rectangular parallelepiped, that is, a cross-sectional shape in a direction orthogonal to the optical axis direction, but is a three-sided cross-section such as a triangular prism, and a cross-section 5 such as a pentagonal prism. Also included are six pentahedrons and hexahedrons with six cross-sections such as hexagonal cylinders. Of course, it may be a hexagonal prism or an octagonal prism. Although it depends on the size of the housing 50, if it is too diversified, the width of one surface is narrow, and it is difficult to form a slit forming the heat flow path 73, or even if it can be formed, its width is narrow and does not function as a heat flow path. Therefore, it is preferable to use an octagonal prism, preferably a polygonal shape having a hexagonal prism or less.

  When the support portion 60 ′ is formed in a polygonal shape in this way, the positional displacement of each member of the support portion 60 ′ in the circumferential direction due to vibration or the like is eliminated as compared with the case of a cylindrical shape. Adjustment errors due to vibrations can be prevented, more stable detection can be performed, detection accuracy can be improved, and optical performance of the detection apparatus 100 can be adjusted.

In each of the above embodiments, the detection means 100 and 100 ′ are detection objects and are used to detect the moving speed of the intermediate transfer belt 105 and the conveyance belt 106 described as the moving member 53. For example, the position of the recording medium S is detected. It is also possible to detect the moving speed. Further, since the displacement amount, that is, the movement amount can be detected, the present invention can also be applied to detection of paper feed accuracy in a so-called ink jet printer type image forming apparatus that records by moving a recording medium intermittently.
In the present embodiment, images of speckle patterns that are different in time on the detection target are acquired, cross correlation calculation is performed between the acquired images of speckle patterns that are different in time, and a position where a correlation peak of the cross correlation calculation occurs However, the image processing circuit 75 is not limited to such a function.
Detection is performed by acquiring images of speckle patterns that differ in time from the object being detected, performing cross-correlation between the acquired images of speckle patterns that differ in time, and determining the position where the correlation peak of the cross-correlation occurs. You may make it derive | lead-out the displacement of a target object. When the displacement of the detection target is derived in this way, it can be applied to detection of distortion of the moving object surface, and the application range is not limited to the image forming apparatus. In addition, since the vibration of the object is included in the displacement of the object in a broad sense, it can be used for detecting the vibration of the object.
That is, the detection method by the detection apparatus 100 configured as the speckle sensor according to the present embodiment irradiates the moving member 53 with the laser light source 51 that emits coherent light and the light emitted from the laser light source 51. Sensor 58 that detects the reflected light from the lens, lenses 55 and 57 that capture an image of the speckle pattern of the reflected light on the area sensor 58, a support portion 60 that supports the lenses 55 and 57, and movement of the moving member 53 At the same time, acquire images of speckle patterns that are temporally different, perform cross-correlation between the acquired images of speckle patterns that are different in time, and determine the shift of the position where the correlation peak of the cross-correlation calculation occurs. The image processing circuit 75 that derives the displacement of the member 53 and the housing 50 that holds these members are provided. The heat flow path 73 that is rotatable around the optical axis and is formed in an asymmetric shape with respect to the optical axis and that communicates the inside and the outside of the housing 50 selectively by rotating around the optical axis. You may make it form.

In each of the above embodiments, the speckle sensor has been described as an example of the detection means. However, the configuration of the detection means is not limited to the speckle sensor, and at least the housing includes a heat source, a light receiving element, and a support portion. It may be provided with a supported optical element. Also in this case, the openings 71 and 72 are formed in the housing, the support portion is configured to be rotatable, a slit is formed in a part thereof, and the support portion is arbitrarily rotated to communicate with the openings 71 and 72. The heat flow path can be selectively formed by setting the state. For this reason, it is possible to suppress the temperature rise of the housing, the support portion, and the optical element supported by the housing, to suppress variation in detection accuracy due to heat, to improve the detection accuracy, and to improve the detection accuracy. The optical performance can be adjusted.
That is, the configuration of the detection device includes a light source 51, a light receiving unit 58 that irradiates the detection target with light emitted from the light source and detects reflected light from the detection target, and an image of the reflected light is captured by the light receiving unit. Optical element lenses 55 and 57, a support part 60 for supporting the optical element, a light source, a light receiving means, an optical element, and a housing 50 for holding the support part. The support part 60 is provided around the optical axis of the optical element. The heat flow path that is rotatable and has an asymmetric shape with respect to the optical axis may be selectively formed by rotating the optical axis around the optical axis.
As a detection method, a light source 51, a light receiving unit 58 that irradiates the detection target with the light emitted from the light source and detects reflected light from the detection target, and an optical that captures an image of the reflected light on the light receiving unit. It includes element lenses 55 and 57, a support portion 60 that supports the optical element, and a light source, a light receiving means, an optical element, and a housing 50 that holds the support portion. The support portion 60 is rotatable about the optical axis of the optical element. In this case, a heat flow path that has an asymmetric shape with respect to the optical axis and rotates around the optical axis may be selectively formed to communicate the inside and the outside of the housing.

1Y, 1M, 1C, 1K Multiple image carriers 4Y, 4M, 4C, 4K Developing device 10 Transfer device 20 Optical scanning device 50 Housing 51 Light source 53 Detection target 55, 57 Optical element 58 Light receiving means 60, 60 ′ Supporting portion 63A, 64A Support member 63A ', 64A' Support member 65, 65 'Rotating member 66, 66' Spacer 73, 73 'Heat flow path 75 Image processing circuit 100, 100' Detection device 105 Intermediate transfer body 200 Speed adjustment means (control means) )
300 Position adjustment device

JP 2010-134190 A

Claims (13)

A light source;
A light receiving means for irradiating the detection object with the emitted light from the light source, and detecting reflected light from the detection object;
An optical element that captures an image of reflected light on the light receiving means;
A support for supporting the optical element;
A housing for holding the light source, the light receiving means, the optical element, and the support;
With
The support portion is rotatable around the optical axis of the optical element, has an asymmetric shape with respect to the optical axis, and communicates the inside and the outside of the housing by rotating around the optical axis. A detection device characterized in that a heat flow path can be selectively formed.   The support portion is composed of a plurality of members arranged in the optical axis direction, and at least one of the members can rotate around the optical axis, and a slit for forming the heat flow path is formed. The detection device according to claim 1, wherein   The detection apparatus according to claim 2, wherein the housing is formed with an opening that communicates the inside and the outside of the housing and also communicates with the slit. The light source emits coherent light,
Obtaining images of speckle patterns that are different in time of the detection object, performing cross-correlation between the acquired images of speckle patterns that are different in time, and obtaining a position where a correlation peak of the cross-correlation operation occurs The detection apparatus according to claim 1, further comprising an image processing circuit for deriving a displacement of the detection target by the method. The light source emits coherent light,
Obtaining images of speckle patterns that are different in time of the detection object, performing cross-correlation between the acquired images of speckle patterns that are different in time, and obtaining a position where a correlation peak of the cross-correlation operation occurs The detection apparatus according to claim 1, further comprising an image processing circuit for deriving a moving speed of the detection object.   The detection device according to claim 1, wherein the support portion is formed in an asymmetric polygonal shape around the optical axis. A plurality of image carriers corresponding to different colors;
An optical scanning device that scans each of the plurality of image carriers with a light beam modulated according to image information of a corresponding color to form a latent image;
A developing device for generating a plurality of toner images by attaching toners of corresponding colors to the latent images formed on the plurality of image carriers, respectively;
A transfer device that includes an intermediate transfer member and transfers the plurality of toner images to a sheet-like medium in an overlapping manner;
An image forming apparatus comprising the detection device according to claim 1 as detection means for detecting movement information of the intermediate transfer member.   The image forming apparatus according to claim 7, further comprising a speed adjusting unit that adjusts a moving speed of the intermediate transfer member based on a detection result of the detection apparatus.   The optical scanning device includes a position adjustment device that individually adjusts incident positions of light in the plurality of image carriers in the sub-scanning direction, and the position adjustment device is based on a detection result of the detection device, 9. The image forming apparatus according to claim 7, wherein light incident positions on the plurality of image carriers are individually adjusted. In an image forming apparatus that forms an image on at least one surface of a sheet-like medium while moving the sheet-like medium,
An image forming apparatus comprising the detection device according to claim 1 as detection means for detecting movement information of the sheet-like medium. A light source;
A light receiving means for irradiating the detection object with the emitted light from the light source, and detecting reflected light from the detection object;
An optical element that captures an image of reflected light on the light receiving means;
A support for supporting the optical element;
A housing for holding the light source, the light receiving means, the optical element, and the support;
With
The support portion is rotatable around the optical axis of the optical element, has an asymmetric shape with respect to the optical axis, and communicates the inside and the outside of the housing by rotating around the optical axis. A detection method comprising selectively forming a heat flow path. A light source that emits coherent light;
A light receiving means for irradiating the detection object with the emitted light from the light source, and detecting reflected light from the detection object;
An optical element that captures an image of a speckle pattern of reflected light on the light receiving means;
A support for supporting the optical element;
Obtaining images of speckle patterns that are different in time of the detection object, performing cross-correlation between the acquired images of speckle patterns that are different in time, and obtaining a position where a correlation peak of the cross-correlation operation occurs An image processing circuit for deriving the displacement of the detection object by:
A housing for holding the light source, light receiving means, optical element, support, and image processing circuit;
With
The support portion is rotatable around the optical axis of the optical element, and is formed in a rotationally asymmetric shape with respect to the optical axis. A detection method characterized by selectively forming a heat flow path communicating with each other. A light source that emits coherent light;
A light receiving means for irradiating the detection object with the emitted light from the light source, and detecting reflected light from the detection object;
An optical element that captures an image of a speckle pattern of reflected light on the light receiving means;
A support for supporting the optical element;
Obtaining images of speckle patterns that are different in time of the detection object, performing cross-correlation between the acquired images of speckle patterns that are different in time, and obtaining a position where a correlation peak of the cross-correlation operation occurs An image processing circuit for deriving the moving speed of the detection object by:
A housing for holding the light source, light receiving means, optical element, support, and image processing circuit;
With
The support portion is rotatable around the optical axis of the optical element, and is formed in a rotationally asymmetric shape with respect to the optical axis. A detection method characterized by selectively forming a heat flow path communicating with each other.

Images