Image forming apparatus, light detection device, and attachment member

Abstract

To improve the visibility of a connector while maintaining the rigidity of a fixation unit.SOLUTION: An image forming apparatus 100 comprises: image carriers 1 or an image carrier 5; a light detection device 7 that detects pattern images formed on the image carrier(s); and a fixation unit 17(170) to which the light detection device is fixed. The light detection device includes a substrate 201, light emitting elements 73, 74 and light receiving elements 71, 72 that are provided on a first surface 201a of the substrate, and a connector 205 that is provided on a second surface 201b of the substrate opposite to the first surface. The fixation unit includes a reference surface 17b(170b) in contact with the second surface of the substrate. In an insertion and withdrawal direction of a cable 300 connected with the connector, a first thickness h_u of a portion of the fixation unit in contact with the second surface from the reference surface is smaller than a second thickness H of a portion of the fixation unit not in contact with the second surface from the reference surface.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to Having a sensor attached to an attachment member an image forming apparatus , a light detection device including the sensor and the attachment member of the sensor, and an attachment member to which the sensor is attached and pertains thereto.

Background Art

[0002] Conventionally, color image forming apparatuses such as copiers, printers, and facsimiles that employ a tandem system correct positional deviation and density deviation for each color. For this purpose, a color deviation detection pattern and a density detection pattern are formed by the image forming units for each color, the amount of color deviation and the amount of density deviation are detected, and the color deviation and the density deviation are corrected. The color deviation detection pattern and the density detection pattern are detected by a light detection device (optical sensor) disposed in the vicinity of the intermediate transfer belt. The light detection device has a light emitting element and a light receiving element. The light emitting element illuminates the intermediate transfer belt and the color deviation detection pattern and the density detection pattern formed on the intermediate transfer belt. The light receiving element receives the reflected light from the intermediate transfer belt and the color deviation detection pattern and the density detection pattern. Based on the difference in the amount of reflected light between the intermediate transfer belt and the color deviation detection pattern and the difference in the amount of reflected light between the intermediate transfer belt and the density detection pattern, the amount of color deviation and the amount of density deviation are detected.

[0003] With the miniaturization of image forming apparatuses, miniaturization of the optical portion of the light detection device has been demanded. Patent Document 1 discloses a light detection device that is miniaturized by shortening the distance between both elements as compared with a conventional configuration in which a light emitting element and a light receiving element are directly mounted on a circuit board and lead components (lead parts) mounted through a lead frame are used. By mounting components for a control circuit, a connector for connecting to an external control device, and other components on the surface opposite to the surface on which the light emitting element and the light receiving element are directly mounted, the circuit board can be miniaturized and the light detection device can be further miniaturized.

[0004] The light detection device is fixed to the image forming apparatus so as to face the intermediate transfer belt. From the viewpoint of assemblability for fixing the light detection device to the image forming apparatus, the light detection device is fixed to a fixing unit in advance, and the fixing unit to which the light detection device is fixed is fixed to the image forming apparatus. Further, the light detection device is fixed to the image forming apparatus so as to be focused on the surface of the intermediate transfer belt in order to detect a color shift detection pattern and a density detection pattern formed on the intermediate transfer belt. Therefore, when fixing the fixing unit to the image forming apparatus, it is necessary to prevent the distance between the light detection device and the intermediate transfer belt from deviating from a predetermined distance due to deformation such as bending of the fixing unit. Accordingly, the thickness of the fixing unit is increased to enhance the rigidity of the fixing unit.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, a circuit board having a connector provided on a surface opposite to the surface on which the optical element and the light receiving element are provided is fixed to the fixing unit by inserting the connector into a through hole provided in the fixing unit. When the thickness of the fixing unit is increased to enhance the rigidity of the fixing unit, the through hole becomes deeper. When connecting a cable through the through hole to a connector provided at the bottom of the deep through hole, the connector is difficult to see, and when connecting the cable to the connector, the hand holding the cable interferes with the fixing unit, resulting in a decrease in connection workability.

[0007] Therefore, the present invention Sensor improves the visibility of the connector and the connection between the connector and the cable Aiming to improve workability .

Means for Solving the Problems

[0008] An image forming apparatus according to an embodiment of the present invention includes an image carrier, a sensor that detects a pattern image formed on the image carrier, a mounting member to which the sensor is attached, and is provided with The sensor includes a substrate, a light emitting element provided on a first surface of the substrate, a light receiving element provided on the first surface of the substrate, and a connector provided on a second surface opposite to the first surface of the substrate, and is provided with The mounting member has a third surface having an opening into which the connector of the sensor is inserted, and has a fourth surface perpendicular to the third surface and parallel to the longitudinal direction of the mounting member. When viewed from one direction perpendicular to the longitudinal direction of the mounting member and parallel to the first surface of the sensor attached to the mounting member, a part of the fourth surface of the mounting member is cut out so that the connector can be easily visually recognized. In the longitudinal direction of the mounting member, the width of the cut-out portion of the fourth surface is wider than the width of the opening The connector inserted therein in the longitudinal direction of the mounting member. characterized in that. An optical detection device according to an embodiment of the present invention is an optical detection device including a substrate, a light emitting element provided on a first surface of the substrate, a light receiving element provided on the first surface of the substrate, and a connector provided on a second surface opposite to the first surface of the substrate, a sensor provided with and a mounting member to which the sensor is attached, The mounting member has a third surface having an opening into which the connector of the sensor is inserted, and has a fourth surface perpendicular to the third surface and parallel to the longitudinal direction of the mounting member. When viewed from one direction that is perpendicular to the longitudinal direction of the mounting member and parallel to the first surface of the sensor attached to the mounting member, a part of the fourth surface of the mounting member is cut out so that the connector can be easily visually recognized. In the longitudinal direction of the mounting member, the width of the cut-out portion of the fourth surface is wider than the width of the opening The connector inserted therein in the longitudinal direction of the mounting member. A mounting member according to an embodiment of the present invention includes a substrate, a light-emitting element provided on a first surface of the substrate, a light-receiving element provided on the first surface of the substrate, and a connector provided on a second surface opposite to the first surface of the substrate. The mounting member is for mounting a sensor including an opening for inserting the connector of the sensor Having and a third surface, a fourth surface perpendicular to the third surface and parallel to the longitudinal direction of the mounting member, and a cut-out portion of a part of the fourth surface of the mounting member so that the connector can be easily visually recognized when viewed from one direction that is perpendicular to the longitudinal direction of the mounting member and parallel to the first surface of the sensor attached to the mounting member. The mounting member has In the longitudinal direction of the mounting member, the width of the cut-out portion of the fourth surface is wider than the width of the opening The connector to be inserted therein in the longitudinal direction of the mounting member.

Advantages of the Invention

[0009] According to the present invention, Sensor the visibility of the connector is improved, and the connection between the connector and the cable Workability can Improvement be performed.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0011] Hereinafter, modes for carrying out the present invention will be described with reference to the accompanying drawings.

Example

[0012] (Image forming apparatus) FIG. 1 is a cross-sectional view of the image forming apparatus 100. The image forming apparatus 100 is a printer that forms a color image on a recording medium S such as a sheet of paper using a plurality of colors of toner by an electrophotographic method. The image forming apparatus 100 includes four image forming units 101 (101Y, 101M, 101C, 101K). The image forming unit 101Y forms a yellow image using yellow toner. The image forming unit 101M forms a magenta image using magenta toner. The image forming unit 101C forms a cyan image using cyan toner. The image forming unit 101K forms a black image using black toner. The subscripts Y, M, C, and K of the reference numerals indicate yellow, magenta, cyan, and black, respectively. In the following description, the subscripts Y, M, C, and K of the reference numerals may be omitted when not particularly necessary. The four image forming units 101 have the same structure except for the color of the developer (toner).

[0013] The image forming unit 101 has a photosensitive drum 1 as a photoreceptor. Around the photosensitive drum 1, a charger 8, an optical scanning device (laser writing unit) 15, a developing device 16, a primary transfer roller 10, and a drum cleaning device 9 are arranged. Below the photosensitive drum 1, an endless intermediate transfer belt (image carrier) 5 is arranged. The intermediate transfer belt 5 rotates and moves in the moving direction R1. The primary transfer roller 10 is arranged to face the photosensitive drum 1 via the intermediate transfer belt 5. The primary transfer roller 10 transfers the toner image on the photosensitive drum 1 to the intermediate transfer belt 5. The secondary transfer roller 4 is arranged to face the belt support roller 3 via the intermediate transfer belt 5. The secondary transfer roller 4 transfers the toner image on the intermediate transfer belt 5 to the recording medium S.

[0014] Below the image forming apparatus 100, a feed cassette 20 for accommodating a recording medium S such as paper (sheet) is arranged. The recording medium S is fed out from the feed cassette 20 by a pickup roller 19, and is conveyed to the secondary transfer roller 4 by a feed roller 22, a conveyance roller 23, and a registration roller 24. In the conveyance direction CD of the recording medium S, a conveyance belt 12 and a fixing device 13 are arranged downstream of the secondary transfer roller 4. The fixing device 13 fixes the toner image onto the recording medium S.

[0015] Next, the image forming process of the image forming apparatus 100 will be described. Since the image forming processes in the four image forming units 101 are the same, the image forming process in the image forming unit 101Y that forms a yellow toner image will be described. Descriptions of the image forming processes in the image forming unit 101M that forms a magenta toner image, the image forming unit 101C that forms a cyan toner image, and the image forming unit 101K that forms a black toner image will be omitted.

[0016] The photosensitive drum 1Y rotates in the direction indicated by the arrow R2 in FIG. 1. The charger 8Y uniformly charges the surface of the photosensitive drum 1Y to a predetermined potential. The optical scanning device 15Y emits a laser beam (light beam) modulated according to the yellow image information from a semiconductor laser (not shown) as a light source, and forms an electrostatic latent image on the uniformly charged surface of the photosensitive drum 1Y. The developing device 16Y develops the electrostatic latent image with yellow toner (developer) to form a yellow toner image. The primary transfer roller 10Y transfers the yellow toner image on the photosensitive drum 1Y onto the intermediate transfer belt 5. The toner remaining on the photosensitive drum 1Y after the primary transfer is recovered by the drum cleaning device 9Y.

[0017] Similarly, the magenta toner image formed by the image forming unit 101M is accurately transferred and overlapped on the yellow toner image on the intermediate transfer belt 5. Hereinafter, the cyan toner image and the black toner image are sequentially transferred and overlapped on the magenta toner image on the intermediate transfer belt 5. As a result, four-color toner images are sequentially overlapped on the intermediate transfer belt 5 to form a color toner image 6.

[0018] The recording medium S conveyed from the supply cassette 20 is conveyed to the secondary transfer roller 4 by the registration roller 24 so that the leading edge of the color toner image 6 on the intermediate transfer belt 5 coincides with the leading edge of the recording medium S. The color toner image 6 on the intermediate transfer belt 5 is transferred to the recording medium S all at once by the secondary transfer roller 4. The toner remaining on the intermediate transfer belt 5 after the secondary transfer is recovered by the intermediate transfer belt cleaner 14. The recording medium S onto which the toner image has been transferred is conveyed to the fixing device 13 by the conveyance belt 12. The fixing device 13 heats and presses the recording medium S to fix the toner image to the recording medium S. The recording medium S on which the image has been formed is discharged out of the image forming apparatus 100 by the fixing exit roller 26 and the discharge roller 27.

[0019] Color misregistration may occur in the color toner image 6 formed on the intermediate transfer belt 5 due to manufacturing variations in the optical scanning device 15 and the photosensitive drum 1, deformation of components due to temperature rise, and conveyance variations in the intermediate transfer belt 5. Color misregistration occurs when the formation positions of the yellow toner image, magenta toner image, cyan toner image, and black toner image are misaligned. Color misregistration is corrected based on the detection results obtained by detecting the misregistration detection pattern formed on the intermediate transfer belt 5 by the pattern sensor (optical sensor) 7.

[0020] Also, the image density varies depending on the temperature and humidity conditions of the environment in which the image forming apparatus 100 is used and the usage frequency of each color. Due to the variation in the image density, a density shift occurs in which the image density deviates from a predetermined density. The density shift is corrected by controlling the optical scanning device 15, the developing device 16, and the photosensitive drum 1 based on the detection results obtained by detecting the density detection pattern formed on the intermediate transfer belt 5 by the pattern sensor 7.

[0021] (Pattern Sensor) The pattern sensor 7 as a light detection device is arranged near the intermediate transfer belt 5. The pattern sensor 7 is fixed to the fixed unit 17 by screws 21 (Fig. 9). The pattern sensor 7 is fixed to the image forming apparatus 100 by the fixed unit 17 such that the distance between the pattern sensor 7 and the intermediate transfer belt 5 becomes a predetermined distance so that the pattern sensor 7 is focused on the surface of the intermediate transfer belt 5. The pattern sensor 7 detects density detection patterns and color shift detection patterns of respective colors formed on the intermediate transfer belt 5 at a predetermined timing. Based on the detection result of the pattern sensor 7, density correction and color shift correction are performed.

[0022] Fig. 2 is an explanatory view of the pattern sensor 7. The pattern sensor 7 has a circuit board (hereinafter referred to as a board) 201. On the surface (first surface) 201a of the board 201, a first photodiode (hereinafter referred to as the first PD) 71 and a second photodiode (hereinafter referred to as the second PD) 72 as light receiving elements are provided. On the surface 201a of the board 201, further, a first light emitting diode (hereinafter referred to as the first LED) 73 and a second light emitting diode (hereinafter referred to as the second LED) 74 as light emitting elements are provided. The first PD 71, the second PD 72, the first LED 73, and the second LED 74 are surface mount type elements and are arranged on one board 201.

[0023] A housing 203 that covers the first PD 71, the second PD 72, the first LED 73, and the second LED 74 is attached to the surface 201a of the board 201. The housing 203 is provided with a lens group 204 including a plurality of lenses 204a, 204b, 204c, and 204d. The lenses 204a, 204b, 204c, and 204d are respectively arranged near the first PD 71, the second PD 72, the first LED 73, and the second LED 74. The housing 203 is provided with light guide paths between the lenses 204a, 204b, 204c, and 204d and the first PD 71, the second PD 72, the first LED 73, and the second LED 74, respectively.

[0024] The light emitted from the first LED 73 as the light emitting unit for regular reflection light travels through the light guide path in the housing 203 and the lens 204c and advances in the direction of the optical axis (the dotted line in FIG. 2), and is irradiated onto the intermediate transfer belt 5. The regular reflection light regularly reflected by the intermediate transfer belt 5 enters the first PD 71 as the light receiving unit for regular reflection light (regular reflection color shift detection light receiving unit, regular reflection density detection light receiving unit) through the lens 204a and the light guide path in the housing 203. As shown in FIG. 2, the first LED 73 and the first PD 71 are arranged at positions such that the incident angle and the reflection angle of the light from the first LED 73 with respect to the intermediate transfer belt 5 are equal. The first PD 71 functions as a light receiving means for receiving the regular reflection light among the light emitted from the first LED 73 to the intermediate transfer belt 5 and reflected by the intermediate transfer belt 5.

[0025] On the other hand, the light emitted from the second LED 74 as the light emitting unit for irregular reflection light travels through the light guide path in the housing 203 and the lens 204d and advances in the direction of the optical axis (the solid line in FIG. 2), and is irradiated onto the intermediate transfer belt 5. The irregular reflection light irregularly reflected by the intermediate transfer belt 5 enters the second PD 72 as the light receiving unit for irregular reflection light (irregular reflection density detection light receiving unit) through the lens 204b and the light guide path in the housing 203. As shown in FIG. 2, the second LED 74 and the second PD 72 are arranged at positions such that the incident angle of the light from the second LED 74 with respect to the intermediate transfer belt 5 and the reflection angle of the irregular reflection light are not equal. The second PD 72 functions as a light receiving means for receiving the irregular reflection light among the light emitted from the second LED 74 to the intermediate transfer belt 5 and reflected by the intermediate transfer belt 5.

[0026] On the back surface (second surface) 201b opposite to the front surface 201a of the substrate 201, a connector 205, a control integrated circuit (hereinafter referred to as control IC) 207, and other mounted components 206 are provided. The control IC 207 has a core chip, which is an integrated circuit, connected to the substrate 201 by wire bonding using the chip-on-board method. A sealing resin is applied to the control IC 207 to protect the core chip and the wire bonding. The control IC 207 controls the operations of the first PD 71, the second PD 72, the first LED 73, and the second LED 74, which are optical elements.

[0027] The connector 205 of the pattern sensor 7 is connected to the connector 301 of the cable 300. The pattern sensor 7 is electrically connected to a CPU 109 (FIG. 3) that controls the entire image forming apparatus 100 via the cable 300 connected to the connector 205. The control IC 207 communicates with the CPU 109 and controls the light emission amounts of the first LED 73 and the second LED 74. The other mounted components 206 include, for example, a capacitor for stabilizing the power supply supplied to the control IC 207. The substrate 201 is provided with a first positioning hole 202a and a second positioning hole 202b, which are openings through which screws 21 (FIG. 9) for fixing the pattern sensor 7 to the fixing unit 17 pass.

[0028] (Electrical Configuration of Image Forming Apparatus) FIG. 3 is a block diagram showing the electrical configuration of the image forming apparatus 100. The image forming apparatus 100 includes a CPU 109, a ROM 111, and an image forming control unit 120 as control means. A cable 300 electrically connects the pattern sensor 7 and the CPU 109. The cable 300 includes signal lines. The CPU 109 controls the lighting of the first LED 73 and the second LED 74 of the pattern sensor 7 by outputting a first light emission signal L1 and a second light emission signal L2 to the control IC 207. The pattern sensor 7 converts the light reception amounts of the first PD 71 and the second PD 72 that receive reflected light from the intermediate transfer belt 5 or the toner pattern formed on the intermediate transfer belt 5 into voltages, respectively, and outputs them as a first detection signal P1 and a second detection signal P2. The first detection signal P1 and the second detection signal P2 are converted from analog signals into digital signals by an analog-to-digital converter (hereinafter referred to as an A / D converter) 110 built in the CPU 109 and input into the CPU 109.

[0029] The image forming control unit 120 includes a light scanning device control unit 112, a developing device control unit 113, a photosensitive drum control unit 114, and an intermediate transfer belt control unit 115. The light scanning device control unit 112 controls the light scanning device 15. The developing device control unit 113 controls the developing device 16. The photosensitive drum control unit 114 controls the photosensitive drum 1. The intermediate transfer belt control unit 115 controls the intermediate transfer belt 5. The CPU 109 is electrically connected to the light scanning device control unit 112, the developing device control unit 113, the photosensitive drum control unit 114, the intermediate transfer belt control unit 115, and the ROM 111.

[0030] The CPU 109 controls the entire image forming apparatus 100 according to various commands. The CPU 109 executes an image forming operation according to a program stored in the ROM 111. The CPU 109 controls the optical scanning device 15, the developing device 16, the photosensitive drum 1, and the intermediate transfer belt 5 by the image forming control unit 120 to form a toner image on the intermediate transfer belt 5. Further, the CPU 109 forms a toner density detection toner pattern (hereinafter referred to as a density detection pattern image) on the intermediate transfer belt 5 according to the toner density detection image data stored in the ROM 111. Further, the CPU 109 forms a color shift detection toner pattern (hereinafter referred to as a color shift detection pattern image) on the intermediate transfer belt 5 according to the color shift detection image data stored in the ROM 111.

[0031] When detecting the amount of color shift, the CPU 109 turns on the first LED 73 of the pattern sensor 7. The first LED 73 illuminates the intermediate transfer belt 5 and the color shift detection pattern image formed on the intermediate transfer belt 5. The first PD 71 receives the reflected light from the intermediate transfer belt 5 and the color shift detection pattern image formed on the intermediate transfer belt 5, and outputs a first detection signal P1 to the A / D converter 110. The A / D converter 110 converts the first detection signal P1 from an analog signal to a digital signal (digital value). The CPU 109 detects the amount of color shift from the digital signal of the first detection signal P1. The CPU 109 calculates a correction amount for the amount of color shift based on the amount of color shift (detection result). The CPU 109 corrects the amount of color shift based on the calculated correction amount.

[0032] When detecting the toner density, the CPU 109 turns on the first LED 73 and the second LED 74 of the pattern sensor 7. The first LED 73 and the second LED 74 illuminate the intermediate transfer belt 5 and the density detection pattern image formed on the intermediate transfer belt 5. The first PD 71 and the second PD 72 receive the reflected light from the intermediate transfer belt 5 and the density detection pattern image formed on the intermediate transfer belt 5, and output the first detection signal P1 and the second detection signal P2 to the A / D converter 110. The A / D converter 110 converts the first detection signal P1 and the second detection signal P2 from analog signals to digital signals (digital values). The CPU 109 detects the toner density level from the digital signals of the first detection signal P1 and the second detection signal P2. The CPU 109 calculates the correction amount of the toner density based on the toner density level (detection result). The CPU 109 corrects the toner density based on the calculated correction amount.

[0033] (Color shift detection pattern image) Next, the color shift detection pattern image formed on the intermediate transfer belt 5 when the CPU 109 executes color shift amount detection will be described. FIG. 4 is a diagram showing the color shift detection pattern image 401. The color shift detection pattern image 401 includes two sets of toner patterns of yellow (Y), magenta (M), cyan (C), and black (K). One set of toner patterns of yellow (Y), magenta (M), cyan (C), and black (K) is inclined at 45° with respect to the moving direction R1 of the intermediate transfer belt 5. Another set of toner patterns of yellow (Y), magenta (M), cyan (C), and black (K) is inclined at -45° with respect to the moving direction R1 of the intermediate transfer belt 5.

[0034] FIG. 5 is a diagram showing the output waveform of the pattern sensor 7 that has detected the color misregistration detection pattern image 401. In the non-pattern portion NP where the base portion of the intermediate transfer belt 5 is visible, since the reflectance of the surface of the intermediate transfer belt 5 is high, the reading level of the first detection signal P1 output from the first PD71 that receives the specularly reflected light is high. On the other hand, in the pattern formation regions where the pattern images of yellow (Y), magenta (M), cyan (C), and black (K) are formed, since the reflectance is lowered by the toner, the reading level of the first detection signal P1 output from the first PD71 that receives the specularly reflected light is low. Therefore, as shown in FIG. 5, the color misregistration amount can be detected by detecting the positions of the toner patterns of yellow (Y), magenta (M), cyan (C), and black (K) using a threshold signal. The CPU 109 corrects the color misregistration by controlling the writing timing of the optical scanning device 15 by the optical scanning device control unit 112 based on the detected color misregistration amount.

[0035] (Density Detection Pattern Image) Next, the density detection pattern image formed on the intermediate transfer belt 5 when the CPU 109 executes density detection will be described. FIG. 6 is a diagram showing the density detection pattern image. FIG. 6(a) is a diagram showing the first density detection pattern image 601 formed on the intermediate transfer belt 5 for toner density detection. The first density detection pattern image 601 is used for the first PD71 to receive the specularly reflected light of the light emitted from the first LED 73. The first density detection pattern image 601 is formed by black (K) toner and is used when performing black (K) toner density detection. Black (K) has the property of absorbing light and cannot be detected by diffusely reflected light, so toner density detection is performed using the detection result of the first PD71 that receives the specularly reflected light.

[0036] The first density detection pattern image 601 shown in FIG. 6(a) is formed by four gradation patterns of 70%, 50%, 30%, and 10% in order from high density. The CPU 109 reads the first density detection pattern image 601 formed on the intermediate transfer belt 5 by the pattern sensor 7, and obtains the first detection signal P1 from the first PD 71. The CPU 109 converts the first detection signal P1 into a digital signal by the A / D converter 110, calculates the difference between the value of the digital signal and the actual image density gradation characteristics to be output, and controls the image formation control unit 120 based on the calculation result to perform density correction.

[0037] FIG. 7 is a diagram showing the output waveform of the pattern sensor 7 that has detected the first density detection pattern image 601. In the 70% part with high density, the light from the first LED 73 is absorbed by the black (K) toner, and since the toner loading amount of the black (K) toner is large, the direct reflection light from the intermediate transfer belt 5 also decreases. Therefore, the reading level of the 70% part with high density is low. On the other hand, in the 10% part with low density, the light absorption amount by the black (K) toner is lower than the light absorption amount of the 70% part, and since the toner loading amount of the black (K) toner is small, the direct reflection light from the intermediate transfer belt 5 increases. Therefore, the reading level of the 10% part with low density is high. In the non-pattern part NP, since the first density detection pattern image 601 is not formed and the direct reflection light from the intermediate transfer belt 5 is large, the reading level is high.

[0038] FIG. 6(b) is a diagram showing a second density detection pattern image 602 formed on the intermediate transfer belt 5 for toner density detection. The second density detection pattern image 602 is used for the second PD 72 to receive the diffused reflection light of the light emitted from the second LED 74. The second density detection pattern image 602 is formed by yellow (Y) toner, magenta (M) toner, and cyan (C) toner, and is used when performing yellow (Y) toner density detection, magenta (M) toner density detection, and cyan (C) toner density detection. FIG. 6(b) shows the second density detection pattern image 602 formed by one color of toner among yellow (Y), magenta (M), and cyan (C). Since yellow (Y), magenta (M), and cyan (C) have a higher diffuse reflectance than the intermediate transfer belt 5, toner density detection is performed using the detection result of the second PD 72 that receives the diffused reflection light.

[0039] The second density detection pattern image 602 shown in FIG. 6(b) is formed of four gradation patterns of 70%, 50%, 30%, and 10% in order from high density. The CPU 109 reads the second density detection pattern image 602 formed on the intermediate transfer belt 5 by the pattern sensor 7 and obtains a second detection signal P2 from the second PD 72. The CPU 109 converts the second detection signal P2 into a digital signal by the A / D converter 110, calculates the difference between the value of the digital signal and the actual image density gradation characteristics to be output, and performs density correction by controlling the image formation control unit 120 based on the calculation result.

[0040] FIG. 8 is a diagram showing the output waveform of the pattern sensor 7 that has detected the second density detection pattern image 602. A case where the second density detection pattern image 602 is formed of yellow (Y) toner will be described. At the 70% portion with high density, the light from the second LED 74 is reflected by the yellow (Y) toner, and since the toner loading amount of the yellow (Y) toner is large, the scattered reflected light from the yellow (Y) toner also increases. Therefore, the reading level at the 70% portion with high density is high. On the other hand, at the 10% portion with low density, since the reflectance by the yellow (Y) toner is lower than the reflectance at the 70% portion, the scattered reflected light decreases. Therefore, the reading level at the 10% portion with low density is low. In the non-pattern portion NP, since the second density detection pattern image 602 is not formed and the scattered reflected light from the intermediate transfer belt 5 is small, the reading level is low. The density detection of the magenta (M) toner and the cyan (C) toner is also performed in the same manner as the toner density detection of the yellow (Y) toner.

[0041] (Fixing unit) Next, the fixing unit 17 to which three pattern sensors 7 are attached will be described with reference to FIG. 9. FIG. 9 is a diagram showing the fixing unit 17 to which the pattern sensor 7 is attached. FIG. 9(a) is a side view of the fixing unit 17 as viewed from the direction indicated by the arrow IXA in FIG. 1. The direction indicated by the arrow IXA is the direction opposite to the moving direction R1 of the intermediate transfer belt 5. The fixing unit 17 has an elongated shape extending in the main scanning direction MS orthogonal to the moving direction R1 (i.e., the sub-scanning direction SS) of the intermediate transfer belt 5. The intermediate transfer belt 5 is disposed in the direction opposite to the direction indicated by the arrow Z (minus direction), that is, on the lower side of FIG. 9(a). Three pattern sensors 7 are fixed to the fixing unit 17 by screws 21 as fixing means, arranged in the main scanning direction MS. The three pattern sensors 7 detect the color shift detection pattern image 401, the first density detection pattern image 601, and the second density detection pattern image 602 formed on the intermediate transfer belt 5.

[0042] The reason why the three pattern sensors 7 are arranged side by side in the main scanning direction MS is to detect different amounts of color misregistration according to the main scanning position by detecting three color misregistration detection pattern images 401 formed side by side in the main scanning direction MS. Further, the reason is to shorten the control time for density detection by detecting three second density detection pattern images 602 of three colors formed side by side in the main scanning direction MS by the three pattern sensors 7 respectively.

[0043] The reason why the pattern sensor 7 is fixed to the fixing unit 17 is to improve the assemblability. The pattern sensor 7 is arranged at a position on the back side in the image forming apparatus 100 in order to detect a pattern image formed on the intermediate transfer belt 5. Here, rather than fixing three pattern sensors 7, which are relatively small components, separately at positions on the back side in the image forming apparatus 100, it is more assemblable to attach a fixing unit 17 to which the three pattern sensors 7 are pre-fixed at a position on the back side in the image forming apparatus 100.

[0044] On the side surface 17s of the fixing unit 17, three openings 17a are provided corresponding to the three pattern sensors 7 fixed to the fixing unit 17. When viewed from the direction indicated by the arrow IXA in FIG. 1, a part of the connector 205 can be seen through the opening 17a.

[0045] FIG. 9(b) is a plan view of the fixing unit 17 viewed from the direction indicated by the arrow IXB in FIG. 1. The sub-scanning direction SS is parallel to the moving direction R1. On the top surface 17t of the fixing unit 17, three openings 17c are provided corresponding to the three pattern sensors 7 fixed to the fixing unit 17. The opening 17c is a through hole penetrating from the top surface 17t to the bottom surface 17b of the fixing unit 17. The connector 205 is inserted into the opening 17c. When viewed from the direction indicated by the arrow IXB in FIG. 1, the connector 205 can be seen through the opening 17c. As shown in FIG. 9(b), the opening 17c communicates with the opening 17a.

[0046] FIG. 9(c) is an end view of the fixed unit 17 as viewed from the direction indicated by the arrow IXC in FIG. 9(a). The back surface (second surface) 201b of the substrate 201 of the pattern sensor 7 is in contact with the bottom surface (reference surface) 17b of the fixed unit 17. FIG. 9(d) is a cross-sectional view of the fixed unit 17 taken along the line IXD-IXD in FIG. 9(a). In order to increase the rigidity, the portion of the fixed unit 17 with which the pattern sensor 7 is not in contact has a thickness (second thickness) H in the Z direction (the insertion / removal direction of the cable 300) with reference to the bottom surface (reference surface) 17b of the fixed unit 17. However, as shown in FIGS. 9(a) and 9(d), the fixed unit 17 has a reduced thickness on the downstream side in the sub-scanning direction SS in the vicinity of the pattern sensor 7. This improves the visibility of the connector 205 and the insertion / removability of the cable 300 of the connector 205 when viewed from the direction indicated by the arrow IXA in FIG. 1.

[0047] As shown in FIG. 9(d), a part (bottom corresponding to the opening 17a) 17e of the portion corresponding to the bottom surface 17b of the fixed unit 17 in contact with the substrate 201 of the pattern sensor 7 has a thickness (first thickness) h_u in the insertion / removal direction of the cable 300 (the direction indicated by the arrow Z). In the insertion / removal direction of the cable 300, the thickness (first thickness) h_u of the part 17e of the portion in contact with the back surface 201b of the substrate 201 of the fixed unit 17 is smaller than the thickness (second thickness) H of the portion not in contact with the back surface 201b of the substrate 201 of the fixed unit 17. A part 17e of the fixed unit 17 having the thickness (first thickness) h_u is within the range of the longitudinal width W of the substrate 201 as shown in FIG. 9(b).

[0048] The thickness h_u of a part 17e of the fixing unit 17 with respect to the bottom surface 17b in the insertion and removal direction of the cable 300 (the direction indicated by the arrow Z) is smaller than the height h_c of the connector 205 of the pattern sensor 7. As a result, when the fixing unit 17 is viewed from the downstream side in the sub-scanning direction SS, the connector 205 can be visually recognized without being hidden by the fixing unit 17. Further, since there is an opening 17a communicating with the opening 17c through which the cable 300 is passed when connecting the cable 300 to the connector 205, it is possible to reduce the interference of the hand holding the cable 300 with the top surface 17t of the fixing unit 17, and the workability is improved. In the present embodiment, the thickness h_u of the bottom portion corresponding to the opening 17a of the fixing unit 17 is equal to or less than two-thirds of the height h_c of the connector 205.

[0049] In the present embodiment, since the fixing unit 17 is attached to the image forming apparatus 100 from the downstream side in the sub-scanning direction SS, the thickness h_u of the bottom portion on the downstream side of the fixing unit 17 is reduced. However, when the fixing unit 17 is attached to the image forming apparatus 100 from the upstream side in the sub-scanning direction SS, the thickness of the bottom portion on the upstream side of the fixing unit 17 may be reduced to improve the visibility of the connector 205 and the insertability and removability of the cable 300.

[0050] In the present embodiment, in order to increase the rigidity of the portion of the fixing unit 17 in the vicinity of the connector 205, as shown in FIG. 9(d), a wall portion 17d is provided on the fixing unit 17. The wall portion 17d reinforces the strength of a part 17e of the fixing unit 17 having a thickness (first thickness) h_u. According to the present embodiment, it is possible to improve the visibility of the connector 205 of the pattern sensor 7 and the insertability and removability of the cable 300 while maintaining the strength of the fixing unit 17, and to improve the assembly quality of the fixing unit 17 to the image forming apparatus 100.

[0051] According to the first embodiment, it is possible to improve the visibility of the connector 205 of the pattern sensor 7 while maintaining the rigidity of the fixing unit 17, and to facilitate the connection between the connector 205 and the cable 300.

Embodiment

[0052] Hereinafter, Example 2 will be described. In Example 2, the same reference numerals are given to the same structures as in Example 1, and the description thereof will be omitted. Since the image forming apparatus 100 and the pattern sensor 7 in Example 2 are the same as those in Example 1, the description thereof will be omitted. The fixing unit 170 in Example 2 is different from the fixing unit 17 in Example 1 in that the wall portion 17d is not provided. Hereinafter, the different points will be mainly described.

[0053] FIG. 10 is a diagram showing the fixing unit 170 of Example 2. FIG. 10(a) is a side view of the fixing unit 170. FIG. 10(b) is a plan view of the fixing unit 170. On one side surface 170s1 of the fixing unit 170, three openings 170a1 are provided corresponding to the three pattern sensors 7 fixed to the fixing unit 170. On the other side surface 170s2 of the fixing unit 170, three openings 170a2 are also provided corresponding to the three pattern sensors 7 fixed to the fixing unit 170. On the bottom surface 170b of the fixing unit 17, three openings 170c are provided corresponding to the three pattern sensors 7 fixed to the fixing unit 17. When viewed along the sub-scanning direction SS, a part of the connector 205 can be seen through the opening 170a2. Also, when viewed along the direction opposite to the sub-scanning direction SS, a part of the connector 205 can be seen through the opening 170a1.

[0054] FIG. 10(c) is an end view of the fixing unit 170 viewed from the direction indicated by the arrow XC in FIG. 10(a). FIG. 10(d) is a cross-sectional view of the fixing unit 170 taken along the line XD-XD in FIG. 10(a). The fixing unit 170 has a thickness H in the Z direction as shown in FIGS. 10(c) and 10(d) in order to increase the rigidity. However, as shown in FIGS. 10(a) and 9(d), the fixing unit 170 has a reduced thickness on the upstream and downstream sides in the sub-scanning direction SS in the vicinity of the pattern sensor 7. Thereby, the visibility of the connector 205 and the insertability and removability of the cable 300 of the connector 205 when viewed from the sub-scanning direction SS and the direction opposite to the sub-scanning direction SS are improved.

[0055] As shown in FIG. 10(d), a part of the thickness h_u of the portion of the fixing unit 170 corresponding to the bottom surface (reference surface) 170b in contact with the substrate 201 of the pattern sensor 7 is thinner than the height h_c of the connector 205 of the pattern sensor 7. As a result, when the fixing unit 170 is viewed from the upstream side or the downstream side in the sub-scanning direction SS, the connector 205 can be visually recognized without being hidden by the fixing unit 170. Further, since there are openings 170a1 and 170a2 that communicate with the opening 170c through which the cable 300 is passed when connecting the cable 300 to the connector 205, it is possible to reduce the interference of the hand holding the cable 300 with the top surface 170t of the fixing unit 170, and the workability is improved.

[0056] According to the second embodiment, it is possible to improve the visibility of the connector 205 of the pattern sensor 7 while maintaining the rigidity of the fixing unit 170 and facilitate the connection between the connector 205 and the cable 300.

[0057] In the first and second embodiments, the pattern sensor 7 is disposed near the intermediate transfer belt 5 and detects a pattern image formed on the intermediate transfer belt 5. However, the pattern sensor (optical sensor) 7 may be disposed near the photosensitive drum (image carrier) 1 and detect a pattern image formed on the photosensitive drum 1. In the first and second embodiments, a plurality of pattern sensors 7 are fixed to the fixing units 17 and 170, but at least one pattern sensor 7 may be fixed to the fixing units 17 and 170.

Explanation of Reference Numerals

[0058] 1 ··· Photosensitive drum 5 ··· Intermediate transfer belt 7 ··· Pattern sensor 17, 170 ··· Fixing unit 17b, 170b ··· Bottom surface 71 ··· First PD 72 ··· Second PD 73 ··· First LED 74 ··· Second LED 100 ··· Image forming apparatus 201 ··· substrate 201a ··· surface 201b ··· back surface 205 ··· connector H ··· second thickness h_u ··· first thickness

Claims

1. An image carrier, a sensor for detecting a pattern image formed on the image carrier, a mounting member to which the sensor is attached, comprising: The sensor includes a substrate, a light-emitting element provided on a first surface of the substrate, a light-receiving element provided on the first surface of the substrate, and a connector provided on a second surface of the substrate opposite to the first surface, comprising: The mounting member includes a third surface having an opening into which the connector of the sensor is inserted, and a fourth surface perpendicular to the third surface and parallel to the longitudinal direction of the mounting member, When viewed from one direction perpendicular to the longitudinal direction of the mounting member and parallel to the first surface of the sensor attached to the mounting member, a part of the fourth surface of the mounting member is cut away so that the connector can be easily visually recognized, The width of the cut-away portion of the fourth surface in the longitudinal direction of the mounting member is wider than the width of the connector inserted into the opening in the longitudinal direction of the mounting member. An image forming apparatus characterized by the above.

2. The sensor is screwed to the mounting member, The image forming apparatus according to claim 1, wherein the connector is located between two screws in the longitudinal direction of the substrate.

3. The image forming apparatus according to claim 2, wherein the cut-away portion of the mounting member is located between the two screws in the longitudinal direction of the substrate.

4. The image forming apparatus according to any one of claims 1 to 3, wherein the height of the connector in a direction perpendicular to the substrate is lower than the height of the mounting member in a direction perpendicular to the substrate.

5. A light detection device comprising a substrate, a light-emitting element provided on a first surface of the substrate, a light-receiving element provided on the first surface of the substrate, and a connector provided on a second surface of the substrate opposite to the first surface, a sensor comprising the above, and a mounting member to which the sensor is attached, wherein The mounting member includes a third surface having an opening into which the connector of the sensor is inserted, and a fourth surface perpendicular to the third surface and parallel to the longitudinal direction of the mounting member, When viewed from one direction perpendicular to the longitudinal direction of the mounting member and parallel to the first surface of the sensor attached to the mounting member, a part of the fourth surface of the mounting member is cut away so that the connector can be easily visually recognized. The optical detection device is characterized in that the width of the notched portion of the fourth surface in the longitudinal direction of the mounting member is wider than the width of the connector inserted into the opening in the longitudinal direction of the mounting member.

6. The sensor is screwed to the mounting member, The optical detection device according to claim 5, wherein the connector is positioned between two screws in the longitudinal direction of the substrate.

7. The optical detection device according to claim 6, wherein the notched portion of the mounting member is positioned between the two screws in the longitudinal direction of the substrate.

8. The optical detection device according to any one of claims 5 to 7, wherein the height of the connector in the direction perpendicular to the substrate is lower than the height of the mounting member in the direction perpendicular to the substrate.

9. A substrate, a light-emitting element provided on a first surface of the substrate, a light-receiving element provided on the first surface of the substrate, a connector provided on a second surface opposite to the first surface of the substrate, A mounting member to which a sensor including these is attached, A third surface having an opening for inserting the connector of the sensor, A fourth surface perpendicular to the third surface and parallel to the longitudinal direction of the mounting member, A portion of the fourth surface of the mounting member is notched so that the connector can be easily visually recognized when viewed from one direction parallel to the first surface of the sensor attached to the mounting member and perpendicular to the longitudinal direction of the mounting member, having The mounting member is characterized in that the width of the notched portion of the fourth surface in the longitudinal direction of the mounting member is wider than the width of the connector inserted into the opening in the longitudinal direction of the mounting member.

10. A plurality of screw holes for screwing the sensor are formed, The mounting member according to claim 9, wherein the opening is positioned between a first screw hole included in the plurality of screw holes and a second screw hole included in the plurality of screw holes.

11. The mounting member according to claim 10, wherein the notched portion is positioned between the first screw hole and the second screw hole.

Images