JP2009216662A - Optical sensor/image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical sensor capable of preventing positional displacements of elements to a printed circuit board surface in a surface-mounted type and sufficiently benefiting from the advantages of the surface-mounted type. <P>SOLUTION: An surface-mount optical sensor 10 is constituted of a light-emitting element 12, a first light-receiving element 14 for receiving regularly reflected light, and a second light-receiving element 16 for receiving diffuse reflected light. The printed circuit board surface 18 to which each element is mounted is arranged approximately at a right angle to a belt surface of an intermediate transfer belt 20. The light-emitting element 12, the first light-receiving element 14 and the second light-receiving element 16 each have a thin-wall plate-like auxiliary member 22 having a lower end side protruding along thickness directions of the printed circuit board surface 18 in their right and left side surfaces and are mounted by inserting the protruding part in a slit-like through-hole 24 provided for the printed circuit board surface 18. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical sensor having a light-emitting element and a light-receiving element that receives reflected light when light emitted from the light-emitting element is reflected by an irradiation object, and more specifically, a surface on which the element is directly installed on a substrate The present invention relates to an image forming apparatus such as a mounting type optical sensor, a copier provided with the optical sensor, a printer, a facsimile, a plotter, and a multifunction machine provided with at least one of them.

In this type of image forming apparatus, in order to obtain a stable image density, a toner patch for density detection (hereinafter also referred to as a “reference pattern”) is created on the surface of an image carrier such as a photoreceptor or an intermediate transfer belt, Some patches detect the density of the patch with an optical sensor (see, for example, Patent Documents 1 and 2).
In such an image forming apparatus, based on the detection result of the optical sensor, the developing potential is adjusted by changing the writing light intensity for forming a latent image, the charging bias, the developing bias, etc. In this case, image density control is performed to adjust the target value of the toner density in the developing device.
This optical sensor is called a P sensor or a P pattern sensor because a reference pattern is a detection target, and a reflective optical sensor including a light emitting element and a light receiving element is generally used.

Some reflective optical sensors detect specularly reflected light when the light irradiated to an irradiation object is specularly reflected. Such a reflective optical sensor is disclosed in Patent Document 1 and the like.
The detection principle when a reflection type optical sensor that detects specularly reflected light is used as the P sensor will be described as follows, taking as an example the case of detecting the toner density (toner adhesion amount) on the photosensitive drum. It is.
When toner does not adhere to the surface of the photosensitive drum (object to be irradiated), the irradiated light is regularly reflected on the surface of the photosensitive drum, and the regular reflected light corresponding to the reflectance of the surface of the photosensitive drum is applied to the light receiving element. Received light.
On the other hand, when the toner adheres to the surface of the photosensitive drum, the irradiation light is absorbed by the toner or diffusely reflected by the toner. Therefore, if the irradiated light is blocked by the toner before reaching the surface of the photosensitive drum, or if the regular reflected light from the surface of the photosensitive drum is blocked by the toner before reaching the light receiving element, the regular reflected light is received by the light receiving element. Is not received.
As the toner adhesion amount on the surface of the photosensitive drum increases, the amount of light received by the light receiving element decreases. Therefore, the toner adhesion amount on the surface of the photosensitive drum can be detected based on the amount of light received by the light receiving element.

As a conventional reflective optical sensor, an optical sensor using a lead-type element is shown in FIG. The P sensor 100 as an optical sensor using a lead-type element includes a first light receiving element 104 that receives specularly reflected light from the light emitting element 102 and the irradiation object 103 in a resin case 101 in which a depression equivalent to the element is formed. The second light receiving element 105 that receives diffusely reflected light from the irradiation object 103 is fixed. In the figure, symbol Z represents the normal line of the surface of the irradiation object 103, θ ₀ represents the incident angle, and θ ₁ represents the reflection angle.
The light emitting element 102, the first light receiving element 104, the second light receiving element 105, and the printed circuit board 106 are connected by a lead wire 107, and a light emission signal or a light reception signal is exchanged with the apparatus main body.
In an optical sensor using a lead-type element, since the element is fixed to the resin case 101, the positioning accuracy of the light emitting element and the light receiving element depends on the processing accuracy of the resin case 101.
Since the resin case 101 is a mold, there is almost no variation in processing accuracy. Therefore, if a resin case matched to the optical system is created, a reflective optical sensor with high element positioning accuracy can be obtained.

On the other hand, there is known an optical sensor using a surface-mounted element in which an element is directly installed on a substrate without a lead (see, for example, Patent Document 3).
This optical sensor is a method that attaches a surface-mount type element to a printed circuit board printed with cream solder, heats the board with a heating device called a reflow furnace, melts the cream solder, and combines the components and the circuit (hereinafter referred to as reflow soldering). It is created through a process.
Therefore, compared with an optical sensor using a conventional lead-type element, cost reduction, productivity improvement, and downsizing of the entire optical sensor can be achieved.

JP-A-08-82599 JP 09-89769 A JP 2005-24459 A

In surface mount type optical sensors, the element is placed on the printed circuit board surface and temporarily fixed, and then the process proceeds to the reflow process. The position of the element is finally fixed on the printed circuit board surface by melting and solidifying the cream solder. Made.
For this reason, if a disturbance such as vibration is applied until the position is completely fixed, the element may rotate. When the element is rotated and misaligned and fixed on the printed circuit board surface, the position and density of the toner on the image carrier are detected differently than when no misalignment occurs. There was a problem that would decrease.

  An object of the present invention is to provide an optical sensor that can suppress the positional deviation of an element in a surface-mounting type with respect to a printed circuit board surface and sufficiently enjoy the advantages of the surface-mounting type, and an image forming apparatus including the optical sensor. To do.

  In order to achieve the above object, according to the first aspect of the present invention, at least one light emitting element and a light receiving element that receives reflected light when the light emitted from the light emitting element is reflected by the irradiation object are printed. In an optical sensor that is provided on a substrate surface and the light emitted from the light emitting element travels substantially parallel to the printed circuit board surface, the light emitting element and the light receiving element extend in a thickness direction of the printed circuit board surface, It has an auxiliary member which can be positioned on the printed circuit board surface by being inserted into a through hole provided on the printed circuit board surface.

According to a second aspect of the present invention, in the optical sensor according to the first aspect, at least one auxiliary member is provided on a side surface of the light emitting element and the light receiving element, and is on the printed circuit board surface after being inserted into the through hole. Rotation of the light emitting element and the light receiving element is prevented.
According to a third aspect of the present invention, in the optical sensor according to the first or second aspect, the through-hole corresponding to the light receiving element is disposed so as to block the light emitted from the light emitting element toward the light receiving element. It is characterized by.

According to a fourth aspect of the invention, in the optical sensor according to any one of the first to third aspects, the auxiliary member is fixed to the through hole after the auxiliary member is inserted into the through hole. And
According to a fifth aspect of the present invention, in the optical sensor according to the fourth aspect, the length of the auxiliary member protruding from the light emitting element and the light receiving element is larger than the thickness of the printed circuit board surface, and the protruding direction of the auxiliary member The front end is bent and engaged with the back side of the printed circuit board surface.

  According to a sixth aspect of the present invention, an image carrier having a surface for regularly reflecting light, a toner image forming unit for forming a toner image on the image carrier, and the toner image forming unit on the image carrier. An image forming apparatus comprising: an optical sensor for detecting an amount of toner adhesion when toner is adhered; and an image density control unit that performs image density control based on a detection result of the optical sensor. An optical sensor according to any one of claims 1 to 5 is used as the sensor.

ADVANTAGE OF THE INVENTION According to this invention, the position shift in the manufacturing process of the element with respect to a printed circuit board surface can be suppressed, and the detection accuracy of a surface mount type optical sensor can be improved.
Moreover, it is possible to suppress leakage light out of the light emitted from the light emitting element from directly reaching the light receiving element by propagating on the printed circuit board surface, thereby further improving the detection accuracy of the optical sensor.

Embodiments of the present invention will be described below with reference to the drawings.
First, a first embodiment will be described based on FIGS. 1 to 3. As shown in FIG. 1, a surface mount optical sensor 10 according to this embodiment includes a light emitting element (light emitting means) 12 and a first light receiving element for receiving specularly reflected light as a light receiving element (light receiving means). 14 and a second light receiving element 16 for receiving diffusely reflected light.
The printed circuit board surface 18 on which the optical sensor 10 is mounted is disposed so as to be substantially perpendicular (substantially perpendicular) to the belt surface of the intermediate transfer belt 20 that is an image carrier as an irradiation object. Compared with the horizontal arrangement method of the printed circuit board 106 that supports the lead type optical sensor shown in FIG. 14, it is possible to prevent the substrate from being bent over time.

In the present embodiment, an LED is used as the light emitting element 12, and a PD (photodiode) is used as the first light receiving element 14 and the second light receiving element 16. Phototransistors may be used as the first light receiving element 14 and the second light receiving element 16.
The optical axis of light emitted from the light emitting element 12 is substantially parallel to the printed circuit board surface 18.
Each of the light emitting element 12, the first light receiving element 14, and the second light receiving element 16 has an auxiliary member, and the auxiliary member is installed by being inserted into a through hole provided on the printed circuit board surface 18. The configuration will be described in detail below.

Since the structure of the auxiliary member and the through hole is the same for any element, the light emitting element 12 will be described as a representative. As shown in FIG. 2, thin plate-like auxiliary members 22 extending in the thickness direction of the printed circuit board surface 18 are fixed to the left and right side surfaces of the light emitting element 12. 12), the through-hole 24 having a size capable of inserting the auxiliary member 22 and preventing displacement in a direction parallel to the substrate surface of the auxiliary member 22 after the insertion is formed in an elongated slit shape. Has been.
The height (length) L of the auxiliary member 22 is set to a size protruding from the lower end of the casing of the light emitting element 12, and the protruding amount L ₁ is smaller than the thickness t of the printed circuit board surface 18. That is, the protruding amount L ₁ is set smaller than the depth of the through hole 24 as shown in FIG. Of course, L ₁ = t may be used.
By inserting the auxiliary member 22 into the through hole 24, the light emitting element 12 can be positioned so as not to rotate on the printed board surface 18.
By performing the reflow process in a state where the positional deviation on the printed circuit board surface 18 is prevented, the light emitting element 12, the first light receiving element 14, and the second light receiving element 16 can be fixed at predetermined positions with uniform accuracy. .

The auxiliary member 22 may be provided only on one side surface. Also in this case, the positioning and rotation preventing function on the printed circuit board surface 18 can be obtained.
In order to prevent displacement of the light emitting element 12 in the vertical direction (thickness direction of the printed circuit board surface 18) after the auxiliary member 22 is inserted into the through hole 24, the auxiliary member 22 is penetrated with an adhesive such as an adhesive or solder. It may be fixed (fixed) to the hole 24 (the same applies to other embodiments below).
In this way, it is possible to prevent the light emitting element 12 from being fixed by solder in a state where it floats upward during the reflow process due to disturbance such as vibration. In this case, the auxiliary member 22 is preferably made of a material having a large bonding effect in relation to the adhesive.
In the present embodiment, the length of the auxiliary member 22 in the vertical direction is made larger than the height of the light emitting element 12 to project the lower end side. However, the present invention is not limited to this, and the height of the auxiliary member 22 is not limited thereto. May be fixed to the lower end portion of the light emitting element 12, and the protruding amount may be the same.
In short, the length of the auxiliary member 22 can be appropriately set within a range in which the positioning with respect to the printed board surface 18 and the rotation preventing function can be obtained.

In the present embodiment, a thin flat plate shape is illustrated as the auxiliary member 22, but the present invention is not limited to this. For example, as shown in FIG. 4, narrow strip-shaped auxiliary members 26 are provided at four corners or two places on one side of the casing of the light emitting element 12 and inserted into the through holes 28 of the printed circuit board surface 18. Also good.
As shown in FIG. 5, columnar auxiliary members 30 in which portions corresponding to the side surfaces of the light emitting element 12 are cut out may be fixed to both side surfaces and inserted into the through holes 32 of the printed circuit board surface 18.
As shown in FIG. 6, the semi-columnar auxiliary member 34 may be fixed to one side surface and inserted into the through hole 36 of the printed circuit board surface 18. Since it has a semi-cylindrical shape, it is possible to obtain a non-rotating function even if one side is fixed.

FIG. 7 shows a second embodiment. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and unless otherwise specified, the description of the configuration and functions already described is omitted, and only the main part will be described (the same applies to other embodiments below).
In the above embodiment, the amount of protrusion of the auxiliary member is set to be equal to or less than the thickness of the printed circuit board surface 18 and is configured to adhere and solidify when fixed to the through hole. However, in this embodiment, the auxiliary member penetrates without using an adhesive. It is characterized by being fixed after being inserted into the hole.
The auxiliary member 38 according to the present embodiment has a thin flat plate shape similar to that shown in FIG. 2 of the first embodiment, but the vertical length thereof is shown in FIGS. ), The size is set so as to protrude beyond the thickness of the printed circuit board surface 18.
That is, the length protruding from the light emitting element 12 is set to be larger than the thickness of the printed board surface 18. The auxiliary member 38 is formed of a plastically deformable material such as metal or resin.

After the insertion, as shown in FIG. 7C, the light emitting element with respect to the printed circuit board surface 18 is obtained without the adhesive by bending the protrusion direction front end 38a of the auxiliary member 38 and engaging with the back surface of the printed circuit board surface 18. Thus, it is possible to prevent the positional deviation of 12 in the vertical direction. In this state, a reflow process is performed.
The bending degree of the distal end portion 38a of the auxiliary member 38 does not necessarily have to be substantially a right angle, and as shown by a two-dot chain line, the engagement function can be obtained even if it is slanted in a letter C shape.

As shown in FIG. 8, the thin-line auxiliary member 40 is fixed to the four corners or two places on one side of the light emitting element 12 and inserted into the through holes 42 of the printed circuit board surface 18. It is good also as a structure bent.
The positions where the auxiliary members are provided are not limited to the left and right and front and rear sides of the light emitting element 12. For example, as shown in FIG. 9, a flat plate-like auxiliary member 44 having protruding edges 44a extending in the thickness direction of the printed circuit board surface 18 at four corners or two places on one side is fixed to the bottom surface as one side surface of the light emitting element 12, and printed The protruding edge 44 a may be inserted into the through hole 46 of the substrate surface 18.
In this case, the length of the projecting edge 44a may be equal to or smaller than the thickness of the printed circuit board surface 18 as in the first embodiment, and may be larger than the thickness and bend the tip portion.

A third embodiment will be described based on FIGS. 11 and 12.
In this type of optical sensor, as described above, the reflected light from the irradiation target is received by the light receiving element, and the change in the amount of received light is detected to detect the change in the state of the irradiation target. Among these, so-called leakage light that propagates through the printed circuit board surface 18 and directly reaches the light receiving element is a factor that lowers the detection accuracy of the optical sensor.
More specifically, the surface of the printed circuit board surface 18 is generally covered with a transparent coat layer, and the first light received by propagating and traveling in the coat layer out of the light emitted from the light emitting element 12. There may be leakage light that reaches the element 14 or the second light receiving element 16 directly.
In the present embodiment, an object is to suppress a decrease in detection accuracy due to the leaked light as much as possible.

As shown in FIG. 10, in the arrangement form of the optical sensor 10 shown in FIG. 1, the light (leakage light) that is emitted from the light emitting element 12 toward the second light receiving element 16 penetrates in the traveling direction. Since the hole 24 intersects the orthogonal state, it is blocked by the through hole 24.
That is, since the coat layer is cut off due to the presence of the through-hole 24, the leakage light 50 propagating through the coat layer is cut off from continuous progression there, and the leakage light radiated and radiated therefrom is also caused by the auxiliary member 22. It is shielded from light or diffuses outside the substrate through the through hole 24.
However, since the first light receiving element 14 is in a state where the longitudinal direction of the through hole 24 is along the traveling direction of the leakage light 50, in other words, the crossing angle with respect to the leakage light 50 is small, the leakage light 50 is directly applied to the first light receiving element 14. There is a high risk of receiving light.

In order to prevent this, in the present embodiment, a thin flat plate-like auxiliary member 52 is provided on the side surface adjacent to the auxiliary member 22 of the first light receiving element 14 in the same manner as the auxiliary member 22. 11, an L-shaped through hole 54 into which the auxiliary member 22 and the auxiliary member 52 can be inserted is formed on the printed circuit board surface 18.
If it does in this way, it can suppress that the leak light 50 reaches | attains the 1st light receiving element 14 directly based on the said principle as much as possible.
In the present embodiment, the case where the auxiliary member is configured by the auxiliary member 22 and the auxiliary member 52 is illustrated, but when the intersection angle with the leakage light 50 is large, only the auxiliary member 52 may be used.
Although the protruding amount of the auxiliary member 22 and the auxiliary member 52 is equal to or less than the thickness of the printed circuit board surface 18, the auxiliary member 22 and the auxiliary member 52 may be bent so as to exceed the thickness.

FIG. 12 shows a fourth embodiment (application example to an image forming apparatus).
Here, an embodiment in which an electrophotographic monochrome laser printer (hereinafter referred to as “monochrome printer”) is applied as an image forming apparatus will be described.
A monochrome printer 100 shown in FIG. 12 includes an optical scanning device 900, a photosensitive drum 901 as a scanning target and an irradiation target, a charging charger 902, a developing device 920 having a developing roller 903 and a toner cartridge 904, and a cleaning blade 905. A paper feed tray 906, a paper feed roller 907, a registration roller pair 908, a transfer charger 911, a fixing roller 909, a paper discharge roller 912, a paper discharge tray 910, a transfer conveyance belt (not shown), and the like.
The charging charger 902, the developing roller 903, the transfer charger 911, and the cleaning blade 905 are disposed in the vicinity of the surface of the photosensitive drum 901, respectively.
The optical scanning device 900, the charging charger 902, and the developing device 920 constitute a toner image forming unit. The photosensitive drum 901 is an image carrier having a surface that regularly reflects light.

With respect to the rotation direction of the photosensitive drum 901, the charging charger 902, the developing roller 903, the transfer charger 911, and the cleaning blade 905 are arranged in this order.
A photosensitive layer is formed on the surface of the photosensitive drum 901. Here, the photosensitive drum 901 rotates in the clockwise direction (arrow direction) within the plane in FIG.
The charging charger 902 uniformly charges the surface of the photosensitive drum 901. The optical scanning device 900 irradiates the surface of the photosensitive drum 901 charged by the charging charger 902 with light modulated based on image information from a host device (for example, a personal computer). As a result, on the surface of the photosensitive drum 901, the charge is lost only in the portion irradiated with light, and a latent image corresponding to the image information is formed on the surface of the photosensitive drum 901. The latent image formed here moves in the direction of the developing roller 903 as the photosensitive drum 901 rotates. A P sensor 914 serving as the above-described optical sensor is provided around the photosensitive drum 901. Details of the operation of the P sensor 914 will be described later.

The toner cartridge 904 stores toner, and the toner is supplied to the developing roller 903. The amount of toner in the toner cartridge 904 is checked when the power is turned on or when printing is completed. When the remaining amount is low, a message prompting replacement is displayed on a display unit (not shown).
As the developing roller 903 rotates, the toner supplied from the toner cartridge 904 is charged and thinly and uniformly attached to the surface thereof. Further, in the developing roller 903, electric fields in opposite directions are generated between a charged portion (a portion not irradiated with light) and an uncharged portion (a portion irradiated with light) in the photosensitive drum 901. Such a voltage is applied.
Due to this voltage, the toner adhering to the surface of the developing roller 903 adheres only to the portion irradiated with light on the surface of the photosensitive drum 901. That is, the developing roller 903 causes the toner to adhere to the latent image formed on the surface of the photosensitive drum 901 and visualizes the image information.
The latent image to which the toner is attached moves in the direction of the transfer charger 911 as the photosensitive drum 901 rotates.
A recording sheet 913 as a transfer object is stored in the sheet feeding tray 906. A paper feed roller 907 is arranged in the vicinity of the paper feed tray 906, and the paper feed roller 907 takes out the recording paper 913 one by one from the paper feed tray 906 and conveys it to the registration roller pair 908.

The registration roller pair 908 is disposed in the vicinity of the transfer roller 911, temporarily holds the recording paper 913 taken out by the paper feed roller 907, and aligns the recording paper 913 with the rotation of the photosensitive drum 901, so that the photosensitive drum 901. And the transfer charger 911 are conveyed on a transfer conveyance belt (not shown).
A voltage having a polarity opposite to that of the toner is applied to the transfer charger 911 in order to electrically attract the toner on the surface of the photosensitive drum 901 to the recording paper 913. With this voltage, the latent image on the surface of the photosensitive drum 901 is transferred to the recording paper 913. The recording sheet 913 transferred here is sent to a fixing device having a fixing roller 909.

In the fixing device, heat and pressure are applied to the recording paper 913, whereby the toner is fixed on the recording paper 913. The fixed recording paper 913 is sent to the paper discharge tray 910 via the paper discharge roller pair 912 and sequentially stacked on the paper discharge tray 910.
The cleaning blade 905 removes toner remaining on the surface of the photosensitive drum 901 (residual toner). The removed residual toner is used again. The surface of the photosensitive drum 901 from which the residual toner has been removed returns to the position of the charging charger 902 again.

The detection of the toner adhesion amount on the surface of the photosensitive drum 901, which is a feature of the present invention, will be described again with reference to FIG. In the printer 100 of the present embodiment, a process control operation (procedure operation) for optimizing the image density of black (Bk) is executed when the power is turned on or every time a predetermined number of prints are performed.
In this process control operation, a density detection toner patch (reference pattern) is formed on the photosensitive drum 901. The reference pattern formed on the photosensitive drum 901 is a continuous tone reference pattern by sequentially switching the charging bias and the developing bias. That is, in this embodiment, a line-shaped reference pattern in which the toner adhesion amount changes in gradation is created along the surface movement direction of the photosensitive drum.
This reference pattern is detected by a P sensor 914 provided in the vicinity of the photosensitive drum 901. Based on the detection result of the P sensor 914, image density control (procedure operation) is performed by a control means (image density control means) (not shown).

FIG. 13 shows a fifth embodiment (example of application to a color image forming apparatus).
The case where the detection of the toner adhesion amount on the surface of the photosensitive drum is applied to a color laser printer (hereinafter referred to as “color printer”) will be described. Compared with a monochrome printer, the color printer according to the present embodiment has an optical scanning device 900, a photosensitive drum 901, and a charging charger (not shown) corresponding to each color of yellow (Y), magenta (M), and cyan (C). A developing roller 903 (not shown), a toner cartridge 904 (not shown), a cleaning blade 905 (not shown), a transfer charger 911 (not shown), and a P sensor 914 (not shown) are added.
The principle of a color printer is almost the same as that of a monochrome printer. In the color printer, the toner adhesion amount is detected by the P sensors 914Y, 914M, 914C, and 914Bk provided in the vicinity of the photosensitive drums 901Y, 901M, 901C, and 901Bk.

FIG. 12 shows the case where the reference pattern on the photosensitive drum is detected. As shown in FIG. 13, the reference pattern formed on each photosensitive drum 901Y, 901M, 901C, 901Bk is transferred to the transfer conveyance belt. A configuration may be adopted in which detection is performed after transfer onto 921.
In this case, the P sensor 914 is disposed at a position facing the tension roller 24 that stretches the transfer conveyance belt 921 together with the driving roller 922 and the driven roller 923. When the reference pattern is detected after being transferred onto the transfer / conveying belt 921, the reference patterns of the respective colors are transferred onto the transfer / conveying belt 921 so as not to overlap each other. In FIG. 13, reference numeral 924 denotes a tension roller.

FIG. 3 is an arrangement configuration diagram of an optical sensor according to the first embodiment of the present invention. It is a perspective view which shows the positional relationship of a light emitting element and a printed circuit board surface. FIGS. 3A and 3B are views showing a state where an auxiliary member of the light emitting element is inserted into a through hole, where FIG. 3A is a cross-sectional view taken along the line A-A in FIG. 2, and FIG. . It is a perspective view which shows the positional relationship of the light emitting element and printed circuit board surface in the modification of 1st Embodiment. It is a perspective view which shows the positional relationship of the light emitting element and printed circuit board surface in the other modification of 1st Embodiment. It is a perspective view which shows the positional relationship of the light emitting element and printed circuit board surface in the further another modification of 1st Embodiment. It is a figure which shows the state which inserted the auxiliary member of the light emitting element which concerns on 2nd Embodiment in the through-hole. It is a perspective view which shows the positional relationship of the light emitting element and printed circuit board surface in the modification of 2nd Embodiment. It is a perspective view which shows the positional relationship of the light emitting element and printed circuit board surface in the other modification of 2nd Embodiment. It is an arrangement block diagram of the optical sensor concerning a 3rd embodiment. It is a perspective view which shows the positional relationship of the 1st light receiving element which concerns on 3rd Embodiment, and a printed circuit board surface. It is a schematic block diagram of the image forming apparatus which concerns on 4th Embodiment. It is a schematic block diagram of the image forming apparatus which concerns on 5th Embodiment. It is an arrangement configuration diagram of a conventional lead type optical sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical sensor 12 Light emitting element 14 1st light receiving element as a light receiving element 16 2nd light receiving element as a light receiving element 18 Printed circuit board surface 20 Intermediate transfer belt 22, 26, 30, 34, 38, 40, 44 as irradiation object Auxiliary member 24, 28, 32, 36, 42, 46, 54 Through hole 901 Photosensitive drum as image carrier

Claims (6)

At least one light emitting element and a light receiving element that receives reflected light when the light emitted from the light emitting element is reflected by an irradiation object are provided on a printed circuit board surface, and the light emitted from the light emitting element is printed. In an optical sensor that travels almost parallel to the substrate surface,
The light emitting element and the light receiving element are:
An optical sensor having an auxiliary member extending in a thickness direction of the printed circuit board surface and capable of being positioned on the printed circuit board surface by being inserted into a through hole provided in the printed circuit board surface. . The optical sensor according to claim 1.
The auxiliary member is provided on at least one side surface of the light emitting element and the light receiving element, and prevents rotation of the light emitting element and the light receiving element on the printed circuit board surface after being inserted into the through hole. A featured optical sensor. The optical sensor according to claim 1 or 2,
The through hole corresponding to the light receiving element is disposed so as to block the light emitted from the light emitting element toward the light receiving element. The optical sensor according to any one of claims 1 to 3,
An optical sensor, wherein the auxiliary member is fixed to the through hole after the auxiliary member is inserted into the through hole. The optical sensor according to claim 4.
The length of the auxiliary member protruding from the light emitting element and the light receiving element is larger than the thickness of the printed circuit board surface, and the front end of the auxiliary member in the protruding direction is bent and engaged with the back surface side of the printed circuit board surface. An optical sensor. An image carrier having a surface for regularly reflecting light, a toner image forming unit for forming a toner image on the image carrier, and the toner image formed on the image carrier by the toner image forming unit. In an image forming apparatus comprising an optical sensor for detecting the amount of toner adhesion, and image density control means for performing image density control based on the detection result of the optical sensor,
An image forming apparatus using the optical sensor according to claim 1 as the optical sensor.

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