JPH09120209A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the existence of residual toner by forming a reflection part reflecting light toward a transparent part in a light emitting part opposed recessed part, and a refelction part reflecting the light toward a light receiving part in a light receiving part opposed recessed part. SOLUTION: The light emitted from the light emitting part 30 is reflected by the reflection part 37a in the light emitting part opposed recessed part 28a formed on a wall part 35 opposed to the light emitting part 30, and transmitted through the transparent part 36a. When a toner quantity in a toner hopper 23 is equal to or above a specified quantity, the light transmitted through the transparent part 36a is intercepted by the toner, so that it does not enter the transparent part 36b in the light receiving part opposed recessed part 28b and does not reach the light receiving part. Meanwhile, when the toner quantity is equal to or under the specified quantity, the light transmitted through the transparent part 36a is not intercepted by the toner, so that it enters the transparent part 36b in the recessed part 28b and further it is reflected by the reflection part 37b and received by the light receiving part 31. Therefore, whether the toner ends or not is judged by detecting whether the light is received by the light receiving part or not.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device applied to an image forming apparatus such as a copying machine, a facsimile or a printer, and more specifically to a visible image of an electrostatic latent image formed on an image carrier. And a toner storage unit for storing toner to be replenished to the development unit, a light emitting unit and a light receiving unit, and a toner remaining amount detecting unit for detecting the toner remaining amount in the toner storing unit. And a developing device.

[0002]

2. Description of the Related Art Conventionally, as a toner remaining amount detecting means used in a developing device of this type, at least an end portion of a light transmitting member which follows a light source which constitutes a part of the detecting means and a light transmitting member which follows a light receiving element. Is provided along the inner wall of the toner containing portion at a position where the toner may exist in the toner containing portion (for example, Japanese Patent Publication No. 2-17112). (See the official gazette).

[0003]

However, when the light transmitting member of the detecting means is provided along the inner wall of the toner accommodating portion as in the above structure, the light emitted from the light emitting portion reaches the light receiving portion. In order to do so, it is necessary to bend the path of light inside the toner accommodating portion, and in order to bend the path of light, an expensive material such as an optical fiber is usually used as the light transmitting member. Therefore, there is a problem in that the manufacturing cost of the toner remaining amount detecting means is increased, which in turn increases the manufacturing cost of the entire developing device.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a developing device equipped with low-cost toner remaining amount detecting means capable of detecting the presence or absence of toner remaining amount. Is.

[0005]

In order to achieve the above object, the invention of claim 1 provides a developing device for visualizing an electrostatic latent image formed on an image carrier, and the developing device. A toner storage unit for storing toner to be replenished, a light emitting unit and a light receiving unit,
In a developing device including a toner remaining amount detecting means for detecting a toner remaining amount in the toner containing portion, a wall portion of the toner containing portion facing the light emitting portion and the light receiving portion is defined as the toner containing portion. A hollow light emitting unit facing recess and a light receiving unit facing recess are formed by projecting inward, and transparent portions transparent to light from the light emitting unit are formed on wall surfaces of the pair of hollow recesses facing each other, A reflecting portion that reflects light from the light emitting portion toward the transparent portion of the light emitting portion facing concave portion is formed in the light emitting portion facing concave portion, and the transparent portion of the light emitting portion facing concave portion is formed in the light receiving portion facing concave portion. It is characterized in that a reflecting portion is formed to reflect the light transmitted through to the light receiving portion.

According to a second aspect of the present invention, in the developing device of the first aspect, the concave portion facing the light emitting portion is configured such that the light from the reflecting portion thereof is vertically incident on the transparent portion.
The light receiving portion facing concave portion is configured such that light passing through the transparent portion of the light emitting portion facing concave portion is perpendicularly incident on the transparent portion of the light receiving portion facing concave portion.

According to a third aspect of the present invention, in the developing device according to the first aspect, among the wall portions of the toner containing section facing the light emitting section and the light receiving section, the light emitting section facing recess and the light receiving section are opposed. It is characterized in that the member of the wall portion other than the recess is made of a material that does not allow light to propagate through the thick portion of the wall portion.

According to a fourth aspect of the present invention, in the developing device according to the first aspect, a wall portion of the toner containing portion facing the light emitting portion and the light receiving portion is provided with a portion of light emitted from the light emitting portion. Even if the portion is reflected by a wall portion of the wall portion other than the light emitting portion facing concave portion and the light receiving portion facing concave portion, the reflected light is reflected in a direction not received by the light receiving portion. It is what

According to a fifth aspect of the present invention, in the developing device according to the first aspect, at least one of the light emitting portion and the light receiving portion is provided with an aperture for limiting the spread of light.

According to a sixth aspect of the invention, in the developing device according to the first aspect, between the light emitting portion and the light receiving portion, the wall portion of the toner containing portion facing the light emitting portion and the light receiving portion is provided. It is characterized in that a light-shielding portion for blocking the reflected light emitted to the wall portion and reflected from the wall portion and the light emitted from the light-emitting portion and directly reaching the light-receiving portion is provided.

According to the first to sixth aspects of the invention, the light emitted from the light emitting portion enters the recess facing the light emitting portion,
This light is reflected by the reflecting portion of the recess facing the light emitting portion and further transmitted through the transparent portion of the recess facing the light emitting portion. Then, the light that has passed through the transparent portion passes through a region in the toner container where toner can exist. Here, when the toner is not present in the toner container, the light that has passed through the area passes through the transparent portion of the concave portion facing the light receiving portion as it is, and is further reflected by the reflecting portion of the concave portion facing the light receiving portion, so that the light receiving portion Is received at. On the other hand, when the toner is present in the toner accommodating portion and the toner is present between the transparent portions formed on the wall surfaces of the pair of hollow concave portions facing each other, the toner is reflected by the reflecting portion of the light receiving portion facing concave portion. Since the light is blocked by the toner after passing through the transmitting portion on the concave portion side facing the light emitting portion,
The light is not received by the light receiving unit. In this way, the light emitted from the light emitting section is bent by the reflecting section provided in each of the opposed concave portions to pass through the area where the toner may exist and to reach the light receiving section, and the remaining toner amount in the toner containing section is reduced. Presence / absence is determined based on presence / absence of light reception by the light receiving unit.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a color printer (hereinafter, referred to as a printer) as an image forming apparatus will be described below. FIG. 1 is a schematic configuration diagram of a printer equipped with a developing device according to the present embodiment. FIG.
In FIG. 1, reference numeral 1 is a flexible photoconductor belt as a belt-shaped image carrier, and the photoconductor belt 1 is composed of rotating rollers 2, 3
It is installed between and is conveyed in the clockwise direction by the driving of the rotating rollers 2 and 3. 4 is a charging member as charging means,
Reference numeral 5 denotes a laser writing system unit as an exposure means, 6 to
Reference numeral 9 denotes a plurality of developing units each containing a developer of a specific color. The laser writing system unit 5 is housed in a holding housing having a slit-shaped exposure opening on the upper surface and is incorporated in the apparatus body. Further, the laser writing system unit 5 may be an optical system in which a light emitting section and a converging optical transmission body are integrated, in addition to the illustrated one. The charging member 4, the laser writing 5D, and the photoconductor cleaning device 15 are provided on one roller 2 of the plurality of rollers that bridge the photoconductor belt 1. The developing units 6 to 9 are, for example, yellow, magenta, cyan,
Each of the black developing agents is accommodated, and each developing sleeve is provided in proximity to or in contact with the photosensitive belt 1 at a predetermined position, and the latent image on the photosensitive belt 1 is visualized by non-contact development or contact development. Has the function of 10
Is an intermediate transfer belt as a transfer image carrier, and the intermediate transfer belt 10 is provided between rotating rollers 11 and 12 and is conveyed counterclockwise by the driving of the rotating rollers. Further, the photoconductor belt 1 and the intermediate transfer belt 10 are in contact with each other by the rotating roller 3, and the first visible image on the photoconductor belt 1 is intermediated by the bias roller 13 provided in the intermediate transfer belt 10. The image is transferred onto the transfer belt 10. Then, by repeating the same process, the second, third, and fourth visible images are superposed on the intermediate transfer belt 10 and transferred without causing positional deviation. In addition, a transfer roller 14 that can contact and separate from the intermediate transfer belt 10 is provided. Reference numeral 15 is a cleaning device for the photosensitive belt 1, 16 is a cleaning device for the intermediate transfer belt 10, and the blade 16A of the intermediate transfer belt cleaning device 16 is kept at a position separated from the surface of the intermediate transfer belt 10 during image formation. As shown in the drawing, the surface of the intermediate transfer belt 10 is pressed against the surface only during cleaning after image transfer.

The process of color image formation by the printer is performed as follows. First, the formation of a multicolor image in the present embodiment is performed according to the following image forming system. That is, data obtained by a color image data input unit (not shown) in which an image sensor scans an original image is processed by an image data processing unit to create image data, which is temporarily stored in an image memory. Next, this image memory is taken out at the time of recording and input to the printer which is the recording unit. That is, when a color signal output from an image reading device separate from this printer is input to the laser writing system unit 5, a laser beam generated by a semiconductor laser (not shown) is generated in the laser writing system unit 5. The polygon mirror 5B rotated by the drive motor 5A rotates and scans fθ.
The optical path is bent by the mirror through the lens 5C, and the peripheral surface of the photoconductor belt 1 that has been previously neutralized by the neutralization lamp 21 and uniformly charged by the charging member 4 is exposed to form an electrostatic latent image. Here, the image pattern to be exposed is a desired full-color image of yellow, magenta, cyan,
It is a monochromatic image pattern when color-separated into black. Each formed electrostatic latent image is developed by a rotary developing device having a yellow, magenta, cyan, and black developing unit and visualized to form a monochromatic image. The monochromatic image formed on the photoconductor belt 1 is transferred onto the intermediate transfer belt 10 which rotates counterclockwise while contacting the photoconductor belt 1. Then, the yellow, magenta, cyan, and black monochromatic images formed on the photoconductor belt 1 are sequentially superposed on the surface of the intermediate transfer belt 10. Then, the yellow, magenta, cyan, and black images superimposed on the surface of the intermediate transfer belt 10 are fed to the paper feed table 17
The image is transferred by the transfer roller 14 to the transfer sheet conveyed from the sheet to the transfer section through the sheet feed roller 18 and the registration roller 19. After the transfer is completed, the transfer paper is fixed by the fixing device 20 to complete a full-color image. The intermediate transfer belt 10 and the photoconductor belt 1 are seamless.

FIG. 2 is a perspective view of the developing device according to the present invention. Reference numerals 22Y, 22M, 22C and 22K are toner cartridges for storing yellow, magenta, cyan and black toners, respectively, and reference numerals 23Y, 23M and 2 are respectively.
Denoted at 3C and 23K are toner hoppers for storing yellow, magenta, cyan, and black toners replenished from toner cartridges. At the time of development, the toner cartridge of each color, the toner hopper, and each of the above-mentioned developing units rotate integrally and stop at the position of the opening 25 to develop the latent image on the photosensitive belt 1.

Further, as shown in FIG. 3, each of the toner cartridges 22 and the developing unit 26 can be replaced depending on the consumption and life of the toner. In particular, the attachment / detachment lever 24 is used to attach / detach the cartridge 22.
Since it is only necessary to operate, the user can easily replace the cartridge 22. Reference numeral 27 in the drawing denotes a developing roller. (Hereinafter, margin)

4 and 5 show a schematic structure of the toner end detecting means according to the present embodiment. The toner end detecting means is provided with a wall portion 35 of the toner hopper 23, which faces a light emitting portion (infrared LED) 30 and a light receiving portion (light receiving element for remote controller) 31 mounted on the same substrate 32.
Has a toner end detecting portion 28 in which a hollow light emitting portion facing concave portion 28a and a light receiving portion facing concave portion 28b are formed by projecting inside the toner hopper 23, and at least the wall surface portions of the pair of hollow concave portions facing each other emit light. It has transparent portions 36a and 36b that are transparent to the light from the portion 30. Further, a reflecting portion 37a that reflects the light from the light emitting portion 30 toward the transparent portion 36a in the light emitting portion facing concave portion 28a is formed in the light emitting portion facing concave portion 28a, and the light emitting portion facing concave portion 28b is formed in the light receiving portion facing concave portion 28b. A reflection portion 37b that reflects the light transmitted through the transparent portion 36b of the recess 28b toward the light receiving portion 31 is formed.

In the present embodiment, each of the recesses 28 is
Although a and 28b are made of a transparent material such as polycarbonate (hereinafter referred to as PC), at least only the wall portions of the pair of hollow concave portions facing each other, that is, the transparent portions 36a and 36b only. May be made of a transparent material. Further, in the example of FIG. 4, the recesses 28a and 28b are provided on the wall portion 35 of the toner hopper 23 on the front side in the drawing, but may be on the back side surface.

Toner end detection in this embodiment is performed as follows. In FIG. 5, first, the light emitted from the light emitting unit 30 is generated by the wall portion 35 facing the light emitting unit 30.
The reflecting portion 37a of the recess 28a facing the light emitting portion formed on the
And is transmitted through the transparent portion 36a. Here, if the amount of toner in the toner hopper 23 is equal to or more than a predetermined amount, the light transmitted through the transparent portion 36a is blocked by the toner, so that the light does not enter the transparent portion 36b of the concave portion 28b facing the light receiving portion. Does not reach. On the other hand, when the amount of toner is less than a predetermined amount, the light transmitted through the transparent portion 36a is not blocked by the toner. Therefore, after entering the transparent portion 36b of the light receiving portion facing concave portion 28b, the light is further reflected by the reflecting portion 37b. The light is reflected and received by the light receiving unit 31. As described above, since the light emitted from the light emitting unit 30 is received by the light receiving unit 31 only when the toner amount is equal to or less than the predetermined amount, by detecting whether or not the light receiving unit 31 light is received, the toner is detected. It can be determined whether or not it is the end.

Further, in the present embodiment, the light emitting portion facing concave portion 28a is constructed so that the light from the reflecting portion 37a is vertically incident on the transparent portion 36a, and
The light receiving portion facing concave portion 28b is configured so that the light passing through the transparent portion 36a of the light emitting portion facing concave portion 28a is vertically incident on the transparent portion 36b of the light receiving portion facing concave portion 28b. In the example of FIG. 5, the incident angle at which the light emitted from the light emitting unit 30 is incident on the reflecting portion 37a of the light emitting unit facing recess 28a, and the reflecting portion 37b of the light receiving unit facing recess 28b.
In, the reflection angles of the light reflected by the light receiving section 31 are both set to 45 degrees. As a result, the light transmittance of the light emitted from the light emitting unit 30 when passing through the transparent portions 36a and 36b is higher than that when the light is incident on the transparent portions 36a and 36b at an angle other than vertical. Therefore, the light amount can be made to reach the light receiving unit 31 without reducing the light amount as much as possible, and the light receiving amount in the light receiving unit 31 can be increased. Therefore, the toner end detection can be performed more reliably.

Although not shown in FIG. 5, the reflecting portions 37a, 37b of the recesses 28a, 28b are not shown.
As a member having a higher light reflectance than the other portions, for example, a silver-colored reflection tape is attached to the surface in contact with the toner. As a result, the light is reflected with a high light reflectance as compared with the case where the reflection tape is not provided, and the light receiving unit 3
The amount of light received at 1 is earned. The reflective tape is more easily adhered to the outer wall surface of the concave portion, that is, the surface in contact with the toner, than to the inner wall surface of the concave portion, and the work efficiency in the manufacturing process is improved. If the reflective tape is attached as described above, the manufacturing cost can be reduced. In addition, the reflector 37
Since a and 37b need only reflect light with a high light reflectance, the reflection parts 37a and 37b are not limited to the above reflection tapes.
It is also possible to configure only the above using a member having a higher light reflectance than other portions, or to vapor-deposit gold only on the reflecting portions 37a and 37b, but it is cheaper to attach the above-mentioned reflecting tape. Can be suppressed.

Here, when a light source with a wide directional angle is used as the light source of the light emitting section 30, as shown in FIG. 6, in addition to the light 33 which should be originally received by the light receiving section 31, the light emitting section 3 is used.
0 and the light receiving portion 31 are incident on the wall portion 35 of the toner hopper 23 facing each other and propagate through the thick portion, and as a result, the light receiving portion 3
Propagation light 38 received at 1 is generated. Since this light is also detected by the light receiving unit 31, the propagating light 38 appears as noise in the detection output, and there is a risk of erroneous detection that there is no toner, even if there is toner.

Therefore, as shown in FIG. 5, the wall portion 35 of the toner hopper 23 is made of black PC as a material through which the light does not propagate through the thick portion of the wall portion 35. As a result, of the light unnecessary for the toner end detection as described above, the propagating light 38 is cut so that the light is not received by the light receiving unit 31. As a result, it is possible to prevent erroneous toner end detection due to the detection of light unnecessary for toner end detection by the light receiving unit 31.

In this embodiment, since the black PC also exhibits the light absorbing property, the reflected light 34 on the wall portion 35 as shown in FIG. 6 is not generated, and the reflected light 34 is not generated. It is also possible to prevent erroneous toner end detection due to detection by the light receiving unit 31. Further, although black PC is used as a material through which light does not propagate in the thick portion, the present invention is not limited to such a material.

Further, the wall portions of the toner hopper 23 facing the light emitting portion 30 and the light receiving portion 31, respectively,
Even if a part of the light emitted from the light emitting portion 30 is reflected by the wall portion 35 of the wall portion other than the light emitting portion facing concave portion 28a and the light receiving portion facing concave portion 28b, the reflected light 34 is received by the light receiving portion 31. You may comprise so that it may be reflected in the direction which is not performed. Specifically, for example, as shown in FIG. 7, the wall portion 35 is arranged so as to be symmetrical with respect to the center line indicated by the reference numeral 29, and the light emitting portion facing concave portion 28a and the light receiving portion facing concave portion 28a.
b is provided, and further, the angle θ formed by the surface parallel to the substrate surface of the substrate 32 and the wall portion 35 is such that the reflected light 34 is reflected in a direction in which it is not received by the light receiving section 31. The wall portion of the toner hopper 23 is configured so that the reflected light 34 reflected by the wall portion 35 is not received by the light receiving portion 31. As a result, it is possible to prevent erroneous detection of the toner end that occurs when the reflected light 34 is received by the light receiving unit 31. In this embodiment, this angle θ
Is 20 degrees, but this angle depends on the layout of the device, the light emission intensity of the light emitting section 30, and the like, so it is necessary to set the angle to an optimum value for each device.

Further, as shown in FIG. 8, the wall portion 35 is
Light emitting portion facing recessed portion 28a and light receiving portion facing recessed portion 28b in
A member 40 for changing the reflection direction of the reflected light 34 so as to reflect the reflected light 34 reflected by the wall portion 35 in a direction such that the reflected light 34 does not reach the light receiving portion 31 may be provided between and. The member 40 may be separate from the wall portion 35 of the toner hopper 23, but if it is formed integrally, the manufacturing cost can be kept low.

Further, as shown in FIG. 9, between the light emitting portion 30 and the wall portion 35, and between the light receiving portion 31 and the wall portion 35.
Apertures 42, 4 that limit the spread of light between
3 may be provided respectively. According to this, the light emitting unit 30
The aperture 42 provided on the side limits the spread of the light emitted from the light emitting portion 30 toward the light emitting portion facing recessed portion 28a, and the light emitting portion facing recessed portion 28a in the wall portion 35 is limited.
The light reflected by the other wall portions 35 can be blocked. Further, by the aperture 43 provided on the light receiving unit 31 side,
Light other than the light that has passed through the light emitting unit facing recess 28a and the light receiving unit facing recess 28b, for example, the reflected light 34 at the wall portion 35, can be blocked before being received by the light receiving unit 31. If the apertures 42 and 43 are provided in either the light emitting section 30 or the light receiving section 31, it becomes difficult for the reflected light 34 to be received by the light receiving section 31, and as shown in FIG. The above-mentioned reflected light 34
Can be blocked more reliably.

As shown in FIG. 10, a partition plate 44 may be provided, for example, on the wall portion 35 of the toner hopper 23 as a light shielding portion for partitioning the light emitting portion 30 and the light receiving portion 31. However, in the developing device of the present embodiment, the toner hopper 23 attached to the partition plate 44 rotates together with the developing unit, so that the length L of the partition plate 44 does not contact the light emitting unit 30 and the light receiving unit 31. The length is set to be shorter than the distance d between the wall portion 35 and the light emitting portion 30 or the light receiving portion 31. Further, in the vicinity of the light emitting portion 30 on the substrate 32, a light shielding member 45 is provided as the light shielding portion, separately from the partition plate 44. As a result, the light emitted from the light emitting portion 30 and reflected by the wall portion 35 is separated by the partition plate 44.
The light that is blocked by the light and reaches the light receiving unit 31 directly is blocked by the light blocking member 45, so that light unnecessary for detection is less likely to be received by the light receiving unit 31, and the toner is in the toner end state even though it is not in the toner end state. It is possible to more reliably prevent erroneous detection.

The partition plate 44 may be formed as a separate member from the wall portion 35, but if it is formed integrally with the wall portion 35, the manufacturing cost can be kept low. Also,
The light blocking member 45 provided separately from the partition plate 44 is
Not limited to the above position, at least one of the light emitting section 30 and the light receiving section 31 can block the light that directly reaches the light receiving section 31.

Here, the toner end detection is performed for the developing unit which is developing while the developing unit is rotated to a predetermined developing position for developing and stopped at the predetermined developing position. For this reason, in the state of being stopped at the predetermined developing position, when the transmissive portions 36a and 36b of the recesses 28a and 28b are arranged side by side in the vertical direction as shown in FIG. When the toner in the toner hopper 23 is consumed and the toner end state is reached, as shown in FIG. 12, the toner may remain in the transmission part 36b located on the lower side in the gravity direction. If such toner remains in the transmissive portion, it is determined that the toner is still present even though the toner is not present in the toner hopper 23, resulting in erroneous detection of toner end. Therefore, in the manner that the toner does not remain when the toner end is detected, the transmissive portions 36a, 3a
It is necessary to arrange each surface of 6b so as to face each other. Specifically, for example, as shown in FIG.
It is desirable to arrange each surface of 6b so as to be parallel to the direction of gravity.

FIG. 13 is a timing chart showing the rotation timing of the developing unit, the developing timing, the blinking timing of the light emitting section, and the output timing of the output signal of the light receiving section among the timing signals used in the toner end detection according to the present embodiment. Is. The developing unit is rotated by a drive pulse sent to a stepping motor (not shown), and the rotation is stopped to start development, and at the same time, toner end detection is performed. Light emitted from the light emitting unit 30 is pulsed at a fundamental frequency of 38 kHz and is turned on at intervals of 600 μs.
This is so-called burst light emission in which ON / OFF is repeated. Further, the ON / OFF operation is repeated 20 times by one toner end detection. In the example shown in the figure, the output signal from the light receiving section 31 is output when the light emitting section 3 is not lit.
H level when no light from 0 is received,
When the burst blinking light from the light emitting unit 30 is received, an L level signal is output. Then, the light receiving unit 3
When the change of L / H is detected 20 times in 1, it is determined that the toner is in the end state.

FIG. 14 shows an example of signal processing means for detecting the toner end. CPU47 and ROM4
8, a RAM 49 and an I / O 51 are connected by an address bus and a data bus indicated by white arrows in the figure, and a clock of a predetermined cycle is supplied from the square wave oscillation circuit 56 to the CPU 47. The signal generated by the square wave oscillation circuit 56 is also used as a timing signal for blinking the light emitting unit 30. And this signal is divided by frequency divider 1 (5
The pulse signal of 38 kHz is generated in 7), the pulse signal of the period of 1.2 ms is generated in the frequency divider 2 (58), and these signals are added by the AND gate 60 to obtain the signal obtained by the LED driver. 61, and the LED 62 of the light emitting unit 30 is turned on by the I / O control signal 51.
Burst flashing 0 times. And the toner hopper 2
In a state where the inside of 3 is the toner end, the light of the LED 62 enters from the transparent portion 36a of the light emitting portion facing concave portion 28a to the transparent portion 36b of the light receiving portion facing concave portion 28b, and is reflected by the reflecting portion 37b of the light receiving portion facing concave portion 28b. To reach the photodiode 64 of the light receiving section 31. Then, this signal is amplified by the amplifier 65, only the signal component is passed by the capacitors 66 and 68, and the amplitude of the signal after passing is limited by the limiter 67. Furthermore, the bandpass filter 69 causes 38 kHz.
, The signal is demodulated by the demodulator 70, integrated by the integrator 71, the signal is compared with the H level signal by the comparator 72, and the obtained signal is counted by the counter 75. I do. If the count value of the counter 75 is 20, the CPU 47 determines that the toner end state is reached, displays the toner end state on the toner end display portion 52, and the user is in the toner end state. Encourage replacement of color toner cartridges.

FIG. 15 shows the CPU 47 according to this embodiment.
6 is a flowchart from the start of toner end detection to the determination of whether or not the inside of the toner hopper is at the toner end. First, when the developing unit stops at the developing position and starts developing, the CPU 47 causes the light emitting unit 30 to move to L level.
The ED 62 is blinked (step S1). And LE
It is determined whether D62 has flashed 20 times in burst (step S2). If the burst blinking is not performed 20 times, the determination is continued until the blinking is performed 20 times. And 2
If it is determined that the burst blinking has occurred 0 times, then the count number N of the counter 75 of the signal processing means is read (step S3). Next, it is determined whether or not this value is 20 (step S4). If the count number N is 20, the toner end display portion 52 for that color is displayed to the effect that the toner is out, and if it is not 20, the process returns to the main routine (step S5). Then, based on the toner end display, it is determined whether the toner cartridge has been replaced (step S6). In this step, until the toner cartridge is replaced, the toner end display section 5
The indication that the toner is out is displayed in 2, and when the toner is replaced, the toner end display is turned off (step S7) and the process returns to the main routine.

According to the above embodiment, it is possible to provide a developing device equipped with a low-cost toner end detecting means capable of detecting the presence / absence of remaining toner. Further, since the presence or absence of the remaining amount of toner is detected by the light emitting unit 30 and the light receiving unit 31 arranged outside the toner hopper 23, as compared with an apparatus having the light emitting unit 30 and the light receiving unit 31 inside the toner hopper 23, There is an advantage that the toner hopper 23 can be easily replaced.

[0034]

According to the first aspect of the present invention, the light emitted from the light emitting portion is bent by the reflecting portions provided in the light emitting portion facing concave portion and the light receiving portion facing concave portion, respectively, and a region where toner may exist is formed. A wall portion of the toner containing portion facing the light emitting portion and the light receiving portion in order to determine whether the toner remaining amount in the toner containing portion passes through and reaches the light receiving portion based on whether the light receiving portion receives light. By protruding to the inside of the toner containing portion to form a hollow light emitting portion facing recess and a light receiving portion facing recess, without using an expensive material such as an optical fiber in the portion corresponding to the pair of recesses, There is an excellent effect that the device can be manufactured at low cost.

According to the second aspect of the present invention, since the light transmittance of each transparent portion is higher than that in the case where the light is incident on each transparent portion at an angle other than vertical, it reaches the light receiving portion. It is possible to secure a large amount of light as much as possible, and it is possible to reliably detect the presence / absence of remaining toner.

According to the third aspect of the invention, the light is emitted from the light emitting portion in the wall portion of the toner containing portion other than the light emitting portion facing recess and the light receiving portion facing recess made of a material that does not propagate light. Of the light, the light that propagates through the thick portion of the wall portion and reaches the light receiving portion is blocked. Therefore, unlike the case where light propagates in the thick portion of the wall portion, it is possible to prevent erroneous detection of the remaining amount of toner that occurs when the propagated light is received by the light receiving unit.

According to the invention of claim 4, a part of the light emitted from the light emitting portion is reflected by a wall portion other than the light emitting portion facing concave portion and the light receiving portion facing concave portion of the wall portion of the toner containing portion. Even in this case, since the reflected light is reflected in the direction in which the light receiving section does not receive the light, it is possible to prevent erroneous detection of the remaining toner amount caused by the reception of the reflected light in the light receiving section.

According to the invention of claim 5, by providing the aperture on the side of the light emitting portion, the spread of the light emitted from the light emitting portion toward the recess facing the light emitting portion is limited, and the wall of the toner containing portion is limited. The light reflected by the wall portion of the portion other than the recess facing the light emitting portion is blocked. Further, even if the aperture is provided on the side of the light receiving unit instead of being provided on the side of the light emitting unit, light other than light that has passed through the recess facing the light emitting unit and the recess facing the light receiving unit, for example, reflection on the wall portion Light or the like is blocked before being received by the light receiving unit.
As described above, the aperture provided in either the light emitting unit or the light receiving unit can prevent erroneous detection of the remaining toner amount caused by the light being received by the light receiving unit. Further, if the apertures are provided in both the light emitting section and the light receiving section, the remaining toner amount can be detected more reliably.

According to the invention of claim 6, the light-shielding portion provided between the light emitting portion and the light receiving portion is emitted from the light emitting portion, and the toner is opposed to the light emitting portion and the light receiving portion. Among the wall portions of the housing portion, the reflected light reflected by the wall portion other than the light emitting portion facing concave portion and the light receiving portion facing concave portion and the light that directly reaches the light receiving portion are blocked, so that these lights are received by the light receiving portion. It is possible to prevent erroneous detection of the remaining toner amount caused by receiving light.

[Brief description of the drawings]

FIG. 1 is a front view illustrating a schematic configuration of a printer according to an embodiment.

FIG. 2 is a perspective view showing a schematic configuration of the developing device.

FIG. 3 is an explanatory view showing a state in which a toner cartridge is removed from a developing unit.

FIG. 4 is an explanatory diagram showing a toner end detection unit provided on a wall portion of a toner hopper.

FIG. 5 is a schematic configuration diagram of a toner end detection unit according to the present exemplary embodiment.

FIG. 6 is an explanatory diagram showing main propagation paths that can be taken before reaching a light receiving unit when a light source having a wide directional angle is adopted as a light source of a light emitting unit.

FIG. 7 is a view showing an angle θ formed by a surface parallel to a substrate surface having a light emitting portion and a light receiving portion and a wall portion of the toner hopper such that reflected light is reflected at a reflection angle which is not received by the light receiving portion. Explanatory drawing which shows the example which comprised the said wall part.

FIG. 8 is an explanatory diagram showing an example in which a member for changing the reflection direction of the reflected light is provided on the wall portion of the toner hopper so that the reflected light reflected by the wall portion is not received by the light receiving unit.

FIG. 9 is an explanatory diagram showing an example in which an aperture for limiting the spread of light is provided between the light emitting portion and the wall portion and between the light receiving portion and the wall portion.

FIG. 10 is an explanatory diagram showing an example in which a partition plate as a light shielding member that partitions the light emitting unit and the light receiving unit is provided on the wall portion of the toner hopper.

FIG. 11 is an explanatory diagram showing an example of the arrangement positions of the light emitting unit facing recesses and the light receiving unit facing recesses where the toner is likely to remain in the transmission unit.

FIG. 12 is an explanatory diagram showing a state in which toner remains on a transmitting portion located on the lower side in the gravity direction.

FIG. 13 is a timing chart showing the rotation timing of the developing unit, the developing timing, the blinking timing of the light emitting unit, and the output timing of the output signal of the light receiving unit.

FIG. 14 is a schematic configuration diagram of a signal processing unit in toner end detection.

FIG. 15 is a flowchart showing the processing from the start of toner end detection until the CPU determines toner end.

[Explanation of symbols]

22 Toner Cartridge 23 Toner Hopper 24 Cartridge Attaching / Detaching Lever 25 Developing Unit Opening 26 Developing Unit Unit 28 Toner End Detecting Part 28a Emitting Part Recessing Recess 28b Receiving Part Recessing Recess 30 Light Emitting Part 31 Light Receiving Part 32 Substrate 35 Wall of toner hopper facing light emitting part and light receiving part 36a Transparent part of recess facing light emitting part 36b Transparent part of recess facing light receiving part 37a Reflecting part of recess facing light emitting part 37b Reflection of recess facing light receiving part Department

Claims (6)

[Claims] 1. A developing device for visualizing an electrostatic latent image formed on an image carrier, a toner accommodating part for accommodating toner to be replenished to the developing device, a light emitting part and a light receiving part. A toner remaining amount detecting means for detecting the amount of toner remaining in the toner containing portion, and a wall portion of the toner containing portion facing the light emitting portion and the light receiving portion. To form a hollow light emitting portion facing concave portion and a light receiving portion facing concave portion by projecting inward, and forming a transparent portion transparent to light from the light emitting portion on wall surfaces of the pair of hollow concave portions facing each other, The light emitting portion facing concave portion is formed with a reflecting portion for reflecting light from the light emitting portion toward the transparent portion of the light emitting portion facing concave portion, and the light receiving portion facing concave portion is provided with the transparent portion of the light emitting portion facing concave portion. The light received through the section is received Developing apparatus is characterized in that to form a reflective portion for reflecting the. 2. The developing device according to claim 1, wherein the light emitting portion facing concave portion is configured such that light from the reflecting portion is vertically incident on the transparent portion, and the light receiving portion facing concave portion is the light emitting portion. The developing device is characterized in that the light passing through the transparent portion in the portion-facing concave portion is vertically incident on the transparent portion in the light-receiving portion facing concave portion. 3. The developing device according to claim 1, wherein among the wall portions of the toner containing portion facing the light emitting portion and the light receiving portion, respectively, the walls other than the light emitting portion facing recess and the light receiving portion facing recess. A developing device, wherein the member of the portion is made of a material that does not allow light to propagate through the thick portion of the wall portion. 4. The developing device according to claim 1, wherein a part of the light emitted from the light emitting portion is provided on the wall portion of the toner containing portion facing the light emitting portion and the light receiving portion, respectively. A developing device, characterized in that, even if the reflected light is reflected by a wall portion other than the light emitting portion facing concave portion and the light receiving portion facing concave portion, the reflected light is reflected in a direction in which the light receiving portion is not received. 5. The developing device according to claim 1, wherein at least one of the light emitting portion and the light receiving portion is provided with an aperture for limiting spread of light. 6. The developing device according to claim 1, wherein the toner is emitted between the light emitting portion and the light receiving portion to a wall portion of the toner containing portion facing the light emitting portion and the light receiving portion, respectively. A developing device, comprising: a light shielding portion that shields reflected light reflected on the wall portion and light emitted from the light emitting portion and directly reaching the light receiving portion.