JP2018137340A - Toner adhesion amount sensor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner adhesion amount sensor capable of reducing defects caused by insufficient wraparound of resin in a lens member.SOLUTION: A toner adhesion amount sensor includes a substrate 2, a light emitting part 3 that performs irradiation with irradiation light, light receiving parts 4 and 5 that receive reflected light, a lens member 7, and a light shielding wall 6w that shields stray light propagating from a first region on the light emitting part 3 side of the lens member 7 toward a second region on the light receiving parts 4 and 5 side. The lens member 7 has a gate part 8 that protrudes from the side surface 7s of the lens member 7 at a position spanning the first region and the second region on the side surface 7s of the lens member 7.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a toner adhesion amount sensor and a manufacturing method thereof.

  The measurement principle of the toner adhesion amount is that the measurement object to which the toner is adhered is irradiated with the irradiation light from the LED, and the reflected light from the measurement object with respect to the irradiation light is decomposed into a P wave component and an S wave component by a polarizing filter. Two photodiodes receive the P wave component and the S wave component. The photodiode outputs an output signal corresponding to the amount of received light, and measures the toner adhesion amount based on these output signals (see, for example, Patent Document 1).

  As a sensor for measuring the toner adhesion amount based on the measurement principle, there is a reflective toner adhesion amount sensor in which an LED and two photodiodes are mounted on one substrate. This toner adhesion amount sensor is used in a copying machine or a printer, and is always exposed to toner powder or paper powder. Some copiers and printers protect the toner adhesion sensor from toner powder, paper dust, etc. with a special cover, but this cannot be completely prevented. Dirt may adhere.

  When dirt adheres to the lens of the toner adhesion amount sensor, the internal reflection in which a part of the irradiation light is reflected by the lens surface is greatly increased due to the dirt. When the greatly increased internal reflection light is incident on the photodiode, the output signal of the photodiode greatly varies under the influence of the internal reflection light. As a result, there arises a problem that the toner adhesion amount of the measurement object cannot be measured accurately.

  In order to solve the above problem, it is effective to provide a light shielding wall between the LED and the two photodiodes. FIG. 9 shows a toner adhesion amount sensor 1 </ b> C in which a light shielding wall 6 w is provided between the LED 3 and the two photodiodes 4 and 5.

  The toner adhesion amount sensor 1C includes a substrate 2, LEDs 3 and photodiodes 4 and 5 provided on the upper surface of the substrate 2, a lens member 7 formed of resin, and a holder 6 having a light shielding wall 6w. The lens member 7 is formed by injecting resin from the gate position (gate portion 28) into the mold in resin injection molding using a mold.

  The light shielding wall 6 w extends to the upper surface of the lens member 7 and suppresses stray light (inner surface reflected light) propagating through the lens member 7 from entering the photodiodes 4 and 5. Therefore, in the toner adhesion amount sensor 1C, the photodiodes 4 and 5 are not easily affected by the internally reflected light, and thus the above-described problem caused by the internally reflected light is solved.

JP 2002-310901 A

  As described above, the lens member 7 of the toner adhesion amount sensor 1C is formed by resin injection from the gate position (the gate portion 28 is formed at the gate position). As shown in FIG. 9, the gate position of the lens member 7 is located above the end of the holder 6 on the side of the photodiodes 4 and 5 with the lens member 7 mounted on the holder 6. In addition, it is necessary to form a gap in the lens member 7 for providing the light shielding wall 6w between the LED 3 and the photodiodes 4 and 5. Due to this gap, in the toner adhesion amount sensor 1C, there is a concern that in the process of forming the lens member 7, the resin is insufficiently wrapped from the photodiodes 4 and 5 to the LED 3 side.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a toner adhesion amount sensor capable of reducing defects caused by insufficient wraparound of a resin in a lens member and a manufacturing method thereof. There is to do.

In order to solve the above problems, a method for manufacturing a toner adhesion amount sensor according to the present invention includes:
A method of manufacturing a toner adhesion amount sensor that irradiates a measurement object with irradiation light and receives reflected light from the measurement object with respect to the irradiation light,
A light emitting unit that irradiates the irradiation light, a light receiving unit that receives the reflected light, and a light shielding wall that is positioned between the light emitting unit and the light receiving unit are provided on the upper surfaces of a plurality of substrates constituting the collective substrate. A sensor assembly production process for producing each formed sensor assembly;
A light emitting lens unit positioned above the light emitting unit when mounted on the upper surface of the substrate, a light receiving lens unit positioned above the light receiving unit when mounted on the upper surface of the substrate, and the light shielding wall. A lens member forming step of forming a lens member having a gap portion to be accommodated by resin injection molding using a mold;
A dicing step of producing a plurality of toner adhesion amount sensors from the sensor assembly by dicing with a dicer in a state where the plurality of lens members are mounted on the upper surface of the sensor assembly;
Including
In the lens member forming step,
A position on the side surface of the lens member and spanning the first region on one side and the second region on the other side across the gap is a gate position for injecting resin into the mold. And

In order to solve the above problems, a toner adhesion amount sensor according to the present invention includes:
A toner adhesion amount sensor that irradiates a measurement object with irradiation light and receives reflected light from the measurement object with respect to the irradiation light,
A substrate,
A light emitting unit for irradiating the irradiation light provided on the upper surface of the substrate;
A light receiving portion provided on an upper surface of the substrate for receiving the reflected light;
A lens member having a light emitting lens part located above the light emitting part and a light receiving lens part located above the light receiving part on the lower surface side;
The lens member is divided into a first region on the light emitting unit side and a second region on the light receiving unit side, and a light shielding wall that blocks stray light propagating from the first region to the second region through the lens member. And comprising
The lens member is made of resin and has a gate portion protruding from the side surface of the lens member at a position on the side surface of the lens member and straddling the first region and the second region. And

  According to these configurations (toner adhesion amount sensor and manufacturing method thereof), the first region on one side (light emitting unit side) and the other side (light receiving unit) on the side surface of the lens member and sandwiching the gap portion in which the light shielding wall is accommodated. And the second region on the side) is set as a gate position for injecting resin into the mold, and protrudes from the side surface of the lens member on the side surface of the lens member and across the first region and the second region. A gate portion is formed. For this reason, in the formation process of a lens member, resin can be directly inject | poured into a 1st area | region and a 2nd area | region. Therefore, when the lens member is formed, the shortage of the resin can be solved.

In the toner adhesion amount sensor,
It is preferable that the gate portion is formed to expand toward the side surface of the lens member.

In the toner adhesion amount sensor,
It is preferable that the gate portion has a roughened surface farthest from the side surface of the lens member.

  According to this configuration, the inner surface reflected light can be dispersed on the roughened surface, so that the light receiving portion is less affected by the inner surface reflected light.

From the viewpoint of roughening the surface of the gate portion (the surface farthest from the side surface of the lens member), the manufacturing method of the toner adhesion amount sensor is as follows.
In the lens member forming step, a gate portion protruding from a side surface of the lens member is formed at the gate position by the resin injection,
In the dicing step, it is preferable that the surface of the gate portion is roughened by the dicer during the dicing process.

  According to this configuration, since the inner surface reflected light can be dispersed on the roughened gate portion surface, a toner adhesion amount sensor that makes the light receiving portion less susceptible to the inner surface reflected light can be manufactured. Further, according to this configuration, since the sensor assembly is cut and the gate portion surface is roughened by dicing, the manufacturing process can be simplified and the cost can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the toner adhesion amount sensor which can reduce the defect resulting from insufficient rounding of the resin in a lens member, and its manufacturing method can be provided.

It is a figure which shows the toner adhesion amount sensor which concerns on 1st Embodiment. FIG. 2 is a toner adhesion amount sensor according to the first embodiment, where (A) is a plan view and (B) is a side view. FIG. 4A is a diagram illustrating a method for manufacturing a toner adhesion amount sensor according to the first embodiment, in which FIG. 5A illustrates a first step, and FIG. 5B illustrates a second step. FIG. 4 is a method for manufacturing a toner adhesion amount sensor according to the first embodiment, where (A) is a diagram illustrating a third step, and (B) is a diagram illustrating a fourth step. FIG. 6 is a toner adhesion amount sensor according to the second embodiment, where (A) is a plan view and (B) is a side view. (A) is a figure which shows the internal surface reflected light in 1st Embodiment. (B) is a figure which shows the internal surface reflected light in 2nd Embodiment. FIG. 7A is a view showing a third step, and FIG. 5B is a view showing a fourth step in a method for manufacturing a toner adhesion amount sensor according to the second embodiment. It is a figure for demonstrating the 4th process in 2nd Embodiment. FIG. 2 is a conventional toner adhesion amount sensor, where (A) is a plan view and (B) is a side view.

  Hereinafter, embodiments of a toner adhesion amount sensor and a manufacturing method thereof according to the present invention will be described with reference to the accompanying drawings.

[First Embodiment]
(Toner adhesion sensor)
FIG. 1 shows a toner adhesion amount sensor 1A according to the first embodiment of the present invention. The toner adhesion amount sensor 1 </ b> A includes a substrate 2, LEDs 3 and photodiodes 4 and 5, a holder 6 on which a light shielding wall 6 w is formed, and a lens member 7.

  The substrate 2 is, for example, a printed wiring board. An LED 3 and photodiodes 4 and 5 are provided on the upper surface of the substrate 2. The LED 3 is provided on one side of the substrate 2 (for example, the left side of the light shielding wall 6w), and the photodiodes 4 and 5 are provided on the other side of the substrate 2 (for example, the right side of the light shielding wall 6w).

  The LED 3 corresponds to the “light emitting unit” of the present invention, and emits visible light or infrared light as irradiation light. Above the LED 3, a light-emitting side P-wave transmission polarizing filter may be provided so that only the P-wave component of the irradiation light is irradiated onto the measurement object 100 (for example, a photoreceptor). In addition, a photodiode for feedback control of the amount of light emitted from the LED 3 may be provided in the vicinity of the LED 3.

  The photodiodes 4 and 5 correspond to the “light receiving part” of the present invention, and one receives the P wave component of the reflected light and the other receives the S wave component of the reflected light. In the present embodiment, the photodiode 4 receives the P wave component of the reflected light and outputs a first output signal corresponding to the amount of received P wave component, while the photodiode 5 outputs the S wave component of the reflected light. It receives light and outputs a second output signal corresponding to the amount of received S wave component.

  Above the photodiode 4, a light receiving side that transmits a P wave component that is a direction component perpendicular to the measurement object 100 in the reflected light and cuts an S wave component that is a direction component perpendicular to the P wave component. A P-wave transmission polarizing filter may be provided. On the other hand, a light receiving side S wave transmitting polarization filter that transmits the S wave component of the reflected light and cuts the P wave component may be provided above the photodiode 5.

  The toner adhesion amount sensor 1 </ b> A includes an arithmetic circuit (not shown) that performs arithmetic processing on the output signals of the photodiodes 4 and 5, and the arithmetic circuit includes the first output signal of the photodiode 4 and the photodiode 5. Based on the difference from the second output signal, the toner adhesion amount on the measuring object 100 is measured. The arithmetic circuit can be disposed, for example, in the vicinity of the photodiodes 4 and 5 on the substrate 2.

  The P wave component of the reflected light reflected at the portion of the measuring object 100 where the toner is not attached is P1, the S wave component is S1, and the P wave component of the reflected light reflected at the portion of the measuring object 100 where the toner is attached is the P wave component. When the P2 and S wave components are S2, the photodiode 4 outputs a first output signal (P1 + P2), and the photodiode 5 outputs a second output signal (S1 + S2). At this time, the arithmetic circuit amplifies the first output signal (P1 + P2) and the second output signal (S1 + S2) K times, and the difference K {between the first output signal K (P1 + P2) and the second output signal K (S1 + S2). (P1 + P2) − (S1 + S2)} is calculated, and an analog voltage corresponding to the difference is output.

  Here, the reflected light in the portion where the toner is attached is irregularly reflected, and the relationship of P2≈S2 is established, while the reflected light in the portion where the toner is not attached is dominated by the P wave, and the relationship of P1> S1 is satisfied. It holds. Therefore, the difference can be approximated as K (P1-S1). In other words, the arithmetic circuit may output an analog voltage corresponding to K (P1-S1) indicating how much the P wave component is biased in the reflected light as a measurement of the toner adhesion amount. When the toner adhesion amount on the measurement object 100 is small, K (P1-S1) increases and the analog voltage increases. On the other hand, when the toner adhesion amount on the measurement object 100 increases, K (P1-S1) decreases. The analog voltage is low.

  The holder 6 is made of a resin that is opaque to the irradiation light of the LED 3. The holder 6 has a first penetration part and a second penetration part that penetrate in the vertical direction. The holder 6 is mounted on the substrate 2 such that the LED 3 is disposed in the first through portion and the photodiodes 4 and 5 are disposed in the second through portion. Moreover, the holder 6 has a light shielding wall 6w between the first penetrating portion and the second penetrating portion. The light shielding wall 6 w extends to the upper surface of the lens member 7 and suppresses the stray light (inner surface reflected light) of the LED 3 propagating through the lens member 7 from entering the photodiodes 4 and 5.

  The lens member 7 is made of a resin that is transparent to the light emitted from the LED 3. The lens member 7 has a light emitting lens portion 7 a located above the LED 3 and a light receiving lens portion 7 b located above the photodiodes 4, 5 on the lower surface side. The lens member 7 has a gap portion in which the light shielding wall 6w can be accommodated, and as shown in FIG. 2, a position across one side surface 7s and the first region on one side and the second region on the other side across the gap portion. The gate portion 8 protrudes from the side surface 7s at (gate position).

  The gate portion 8 is formed in a divergent shape from the outer surface (surface 8s described later) of the lens member 7 toward the side surface 7s. In other words, the gate portion 8 is formed in a shape in which the cross-sectional area increases as it approaches the side surface 7s.

  The lens member 7 is formed by resin injection from a gate position in resin injection molding using a mold. In the present embodiment, as described above, the gate position extends over the first region (the region on the LED 3 side) and the second region (the region on the photodiode 4 and 5 side) with the gap portion interposed therebetween. In the forming step, the resin can be directly injected into the first region and the second region. As a result, the shortage of the resin in the lens member forming process is solved.

  Therefore, according to the toner adhesion amount sensor 1 </ b> A according to the present embodiment, it is possible to reduce defects due to insufficient resin wraparound in the lens member 7.

(Manufacturing method of toner adhesion amount sensor)
Next, a manufacturing method of the toner adhesion amount sensor 1A according to the present embodiment will be described. The manufacturing method according to the present embodiment includes a first step shown in FIG. 3 (A), a second step shown in FIG. 3 (B), a lens member forming step, and a third step shown in FIG. 4 (A). And a fourth step shown in FIG.

  In the first step shown in FIG. 3A, components such as LEDs 3, photodiodes 4, 5 and an arithmetic circuit are mounted on the upper surfaces of a plurality of (in this embodiment, 10) substrates 2 constituting the collective substrate 20. Is done. In FIG. 3A, components mounted on the upper surface of the substrate 2 are omitted.

  In the second step shown in FIG. 3 (B), a plurality of (in this embodiment, ten) holders 6 constituting the holder assembly 60 are mounted on the upper surfaces of the plurality of substrates 2 on which components are mounted. Thereby, the “sensor assembly” of the present invention is produced. The first step and the second step correspond to the “sensor assembly manufacturing step” of the present invention.

  In the lens member forming step, the lens member 7 is formed by resin injection molding using a mold. The lens member 7 has a gap portion in which the light emitting lens portion 7 a, the light receiving lens portion 7 b, and the light shielding wall 6 w of the holder 6 are accommodated. In the lens member forming step, the first region (the region on the LED 3 side) on one side and the second region (the region on the photodiode 4, 5 side) on the other side of the side surface 7s of the lens member 7 with the gap interposed therebetween. The straddling position is the gate position where the resin is injected into the mold.

  Thereby, since resin is directly inject | poured into a 1st area | region and a 2nd area | region, the shortage of wraparound of resin is eliminated. As a result, defects due to insufficient rounding of the resin in the lens member 7 are reduced. In the lens member forming step, the gate portion 8 is formed at the gate position of the lens member 7, but in the manufacturing method according to the present embodiment, at least a part of the gate portion 8 is removed before the next third step. May be.

  In the third step shown in FIG. 4A, a plurality of (in this embodiment, ten) lens members 7 produced in the lens member forming step are mounted on the upper surface of the sensor assembly produced in the second step. .

  In the fourth step shown in FIG. 4 (B), a plurality (ten in this embodiment) of toner adhesion amount sensors 1A are produced from the sensor assembly on which the lens member 7 is mounted in the third step by division processing. Is done. A method for dividing the sensor assembly into the plurality of toner adhesion amount sensors 1A is not particularly limited, but preferably, after the folding process is performed along the V-cut groove of the line L2, along the line L1. Then, dicing is performed by a dicer. The third step and the fourth step correspond to the “dicing step” of the present invention.

[Second Embodiment]
(Toner adhesion sensor)
FIG. 5 shows a toner adhesion amount sensor 1B according to the second embodiment of the present invention. The toner adhesion amount sensor 1B is different from the toner adhesion amount sensor 1A according to the first embodiment in that the gate portion 18 is formed on the lens member 7, and is otherwise common to the toner adhesion amount sensor 1A. .

  Similarly to the gate portion 8 of the first embodiment, the gate portion 18 of the present embodiment includes a first region (the region on the LED 3 side) and a second region (photodiode) on the side surface 7s of the lens member 7 with the gap portion interposed therebetween. 4 and 5 side regions). Therefore, as in the first embodiment, the resin can be directly injected into the first region and the second region in the lens member forming step, and defects due to insufficient entrainment of the resin in the lens member 7 can be reduced. .

  In the gate portion 18 of the present embodiment, the surface 18s farthest from the side surface 7s of the lens member 7 is roughened. On the other hand, as shown in FIG. 6A, when the surface 8s of the gate portion 8 farthest from the side surface 7s of the lens member 7 is not roughened, the irradiation light of the LED 3 propagates to the gate portion 8. The light reflected from the surface 8 s of the gate portion 8 may be incident on the photodiodes 4 and 5.

  In contrast, as shown in FIG. 6B, the toner adhesion amount sensor 1B according to the present embodiment is internally reflected by the surface 18s of the gate portion 18 even if the irradiation light of the LED 3 propagates to the gate portion 18. Light is dispersed. As a result, the photodiodes 4 and 5 are not easily affected by the internally reflected light.

(Manufacturing method of toner adhesion amount sensor)
Next, a manufacturing method of the toner adhesion amount sensor 1B according to the present embodiment will be described. The manufacturing method according to the present embodiment includes a first step, a second step, a lens member forming step, a third step, and a fourth step. Since the first step and the second step are common to the manufacturing method according to the first embodiment, description thereof is omitted here.

  In the lens member forming step, the lens member 7 is formed by resin injection molding using a mold, as in the manufacturing method according to the first embodiment. The position across the side surface 7s of the lens member 7 and the first region (the region on the LED 3 side) on one side and the second region (the region on the photodiode 4, 5 side) on the other side across the gap is a mold. This is the gate position where the resin is injected into the substrate. A gate portion 18 is formed at the gate position. In the manufacturing method according to the present embodiment, the gate portion 18 is formed with a length protruding from the side surface of the lower portion of the lens member 7.

  In the third step shown in FIG. 7A, a plurality (ten in this embodiment) of lens members 7 produced in the lens member forming step are mounted on the upper surface of the sensor assembly produced in the second step. . At this time, the gate portion 18 protrudes from the side surfaces of the substrate 2 and the holder 6.

  In the fourth step shown in FIG. 7B, a plurality (10 in this embodiment) of sensor assemblies on which the lens member 7 is mounted in the third step are obtained by dicing by the dicer D shown in FIG. The toner adhesion amount sensor 1B is produced. Strictly speaking, after the folding process is performed along the V-cut groove of the line L2, the dicing process is performed along the line L1.

  In the dicing process, in addition to the holder assembly 60 being cut, portions of the gate portion 18 protruding from the side surfaces of the substrate 2 and the holder 6 are also cut. At this time, the surface 18s (cut surface) of the gate portion 18 is roughened.

  The roughness of the surface 18s due to the roughening can be controlled according to the rotation speed of the dicer D and / or the cutting speed (movement speed) of the dicer D. For example, the roughness of the surface 18s can be increased by reducing the rotation speed and the cutting speed of the dicer D. However, since the holder assembly 60 is also cut at the same time, it is necessary to ensure a speed at which the holder assembly 60 can be cut.

  Eventually, according to the manufacturing method according to the present embodiment, the first region (region on the LED 3 side) on one side and the second region (photodiode 4,. 5) is a gate position for injecting the resin into the mold, so that the shortage of the resin in the lens member forming process can be solved.

  Further, according to the manufacturing method according to the present embodiment, the holder assembly 60 is cut and the gate portion 18 is roughened by dicing in the fourth step without separately providing a roughening step for the gate portion 18. Since it is performed simultaneously, the manufacturing process can be simplified and the cost can be reduced.

[Modification]
Although the embodiments of the toner adhesion amount sensor and the manufacturing method thereof according to the present invention have been described above, the present invention is not limited to the above embodiments.

  For example, the lens member 7 has a gap portion in which the light shielding wall 6w of the holder 6 can be accommodated, and the first region (the region on the LED 3 side) on one side and the other side of the side surface 7s of the lens member 7 with the gap portion interposed therebetween. If the gate portion 8 (18) protruding from the side surface 7s is provided at a position across the second region (photodiode 4, 5 side region) on the side, the configuration can be changed as appropriate.

  The gate portion 8 (18) is preferably formed in a divergent shape toward the side surface 7s of the lens member 7, but is not necessarily in a divergent shape and can be changed to an arbitrary shape.

  As long as the stray light (inner surface reflected light) of the LED 3 propagating through the lens member 7 can be prevented from entering the photodiodes 4 and 5, the height and shape of the light shielding wall 6 w can be changed as appropriate. For example, the light shielding wall 6 w may protrude from the upper surface of the lens member 7 or may not reach the upper surface of the lens member 7.

  The “light emitting part” of the present invention can be composed of a light emitting element other than the LED 3. In addition, the “light receiving unit” of the present invention may be constituted by one photodiode or a light receiving element other than the photodiodes 4 and 5.

1A, 1B Toner adhesion amount sensor 2 Substrate 3 LED (light emitting part)
4, 5 Photodiode (light receiving part)
6 Holder 6w Light-shielding wall 7 Lens member 7a Light-emitting lens portion 7b Light-receiving lens portion 8, 18 Gate portion 20 Collective substrate 60 Holder assembly 100 Measurement object

Claims (5)

A method of manufacturing a toner adhesion amount sensor that irradiates a measurement object with irradiation light and receives reflected light from the measurement object with respect to the irradiation light,
A light emitting unit that irradiates the irradiation light, a light receiving unit that receives the reflected light, and a light shielding wall that is positioned between the light emitting unit and the light receiving unit are provided on the upper surfaces of a plurality of substrates constituting the collective substrate. A sensor assembly production process for producing each formed sensor assembly;
A light emitting lens unit positioned above the light emitting unit when mounted on the upper surface of the substrate, a light receiving lens unit positioned above the light receiving unit when mounted on the upper surface of the substrate, and the light shielding wall. A lens member forming step of forming a lens member having a gap portion to be accommodated by resin injection molding using a mold;
A dicing step of producing a plurality of toner adhesion amount sensors from the sensor assembly by dicing with a dicer in a state where the plurality of lens members are mounted on the upper surface of the sensor assembly;
Including
In the lens member forming step,
A position on the side surface of the lens member and spanning the first region on one side and the second region on the other side across the gap is a gate position for injecting resin into the mold. A method for manufacturing a toner adhesion amount sensor. In the lens member forming step, a gate portion protruding from a side surface of the lens member is formed at the gate position by the resin injection,
2. The method for manufacturing a toner adhesion amount sensor according to claim 1, wherein in the dicing step, the surface of the gate portion is roughened by the dicer during the dicing process. A toner adhesion amount sensor that irradiates a measurement object with irradiation light and receives reflected light from the measurement object with respect to the irradiation light,
A substrate,
A light emitting unit for irradiating the irradiation light provided on the upper surface of the substrate;
A light receiving portion provided on an upper surface of the substrate for receiving the reflected light;
A lens member having a light emitting lens part located above the light emitting part and a light receiving lens part located above the light receiving part on the lower surface side;
The lens member is divided into a first region on the light emitting unit side and a second region on the light receiving unit side, and a light shielding wall that blocks stray light propagating from the first region to the second region through the lens member. And comprising
The lens member is made of resin and has a gate portion protruding from the side surface of the lens member at a position on the side surface of the lens member and straddling the first region and the second region. A toner adhesion amount sensor. The toner adhesion amount sensor according to claim 3, wherein the gate portion is formed so as to expand toward the side surface of the lens member. 5. The toner adhesion amount sensor according to claim 3, wherein the gate portion has a roughened surface most distant from a side surface of the lens member.

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