JP2008299153A - Light guide member, process cartridge, and electrophotographic image forming apparatus - Google Patents

Abstract

The present invention provides a toner and sheet detection means that reduces costs with the goal of reducing the number of parts and simplifying assembly, and also contributes to downsizing of an image forming apparatus by space saving.
In a cleaning container 61, a first light emitting element 90a that emits a first detection light 76a for detecting a sheet S on a frame 30 of an image forming apparatus main body facing each other across a conveyance path of the sheet S is provided. A second light emitting element 90b that emits second detection light 76b for detecting the remaining amount of the removed toner is disposed. In addition, first and second light receiving elements 91a and 91b that receive the first and second detection lights 76a and 76b are arranged. The detection light is exchanged between the light emitting means and the light receiving means, and one member for guiding the detection light for detecting the presence or absence of the sheet S in the conveyance path and the remaining amount of toner in the cleaning container 61 is introduced. The optical member 71 is collected. As a result, the number of parts is reduced and the increase in size of the apparatus is suppressed.
[Selection] Figure 3

Description

  The present invention relates to an electrophotographic image forming apparatus that forms an image using an electrophotographic process, a process cartridge that is attached to and detached from the electrophotographic image forming apparatus, and a light guide member that guides detection light.

  An electrophotographic image forming apparatus refers to an apparatus that forms an image on a transfer material using an electrophotographic image forming system. Specific examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, a facsimile machine, an electrophotographic printer such as a laser beam printer or an LED printer, and a word processor. Hereinafter, these are collectively referred to as “image forming apparatus”.

  Further, the process cartridge is an image forming apparatus main body in which at least one of a charging device, a developing device, and a cleaning device is mounted around the electrophotographic photosensitive drum as an image carrier to integrally form a cartridge. It can be easily attached and detached.

  In an image forming apparatus such as a printer using an electrophotographic process, the drum surface of a photosensitive drum is uniformly charged, and a latent image is formed on the drum surface by exposure according to image information. The latent image is visualized as a toner image using a developer (hereinafter referred to as “toner”) and transferred to a recording medium (hereinafter referred to as “sheet”) such as plain paper or an OHP sheet. The transferred toner image is heated and pressed by a fixing device to be fixed on the sheet, thereby recording an image. In order to execute such image processing without hindrance, toner replenishment or maintenance work for various process members is required.

  In order to simplify toner replenishment and maintenance work, the above-described process cartridge integrated with a photosensitive drum is practically used. Since the user can easily attach and remove the process cartridge to / from the image forming apparatus main body, troublesome operations such as toner replenishment and maintenance become very easy.

  Usually, a light transmission type toner detecting means for detecting the remaining amount of toner is mounted inside the process cartridge. For example, the detection light emitted from the light emitting element is allowed to pass through the first light guide member to irradiate the toner containing container. The irradiated detection light passes through the second light guide member provided also in the toner container and reaches the light receiving element. By detecting whether or not the light receiving element has received the detection light, the remaining amount of the toner in the toner container is determined as to whether or not the necessary amount is sufficient. As a technique related to the toner remaining amount detection, there is a developing device previously proposed by the applicant of the present application (for example, see Patent Documents 1, 2, and 3).

  On the other hand, in the image forming apparatus main body, the presence or absence of whether or not the sheet has passed or whether or not the sheet is being conveyed is detected by disposing the sheet detecting means at the important point of the conveying path. . Examples of such sheet detection means include reflection type and transmission type optical sensors (see, for example, Patent Documents 4 and 5).

  In the case of the former reflective optical sensor, for example, the light emitting element and the light receiving element are arranged on one substrate, and the substrate and the reflecting portion are arranged on one side and the other side across the sheet conveyance path. Therefore, if the sheet has not passed, the detection light emitted from the light emitting element is reflected by the reflecting portion. When the reflected light is received by the light receiving element, it is determined that the sheet is “none”. On the other hand, when the conveyed sheet passes through the optical sensor, the detection light emitted from the light emitting element is blocked by the passing sheet, thereby determining that the sheet is “present”.

   In the case of the latter transmissive optical sensor, the light emitting element and the light receiving element are arranged facing each other across the sheet conveyance path, and when the light emitted from the light emitting element is blocked by the passage of the sheet, it is detected. It is determined that the sheet is “present”.

Japanese Patent Laid-Open No. 11-194602 JP 2001-125363 A JP 2003-131479 A Japanese Patent Application No. 4-207509 Japanese Patent Application No. 5-23381

  By the way, as described above, the toner detection means and the sheet detection means, each composed of a light emitting element and a light receiving element, are mounted at different parts in the main body of the image forming apparatus. In each of these parts, related parts necessary for detection, such as a light guide member for guiding detection light emitted from the light emitting element and returning it to the light receiving element, are uniquely provided.

  Accordingly, in order to detect the sheet and the toner, not only the light emitting element and the light receiving element but also a light guide member is required independently. If the number of parts increases, it is necessary to secure a large amount of mounting space. Therefore, it is difficult to reduce the size of the main body of the image forming apparatus, and the assembly work may be troublesome.

  An object of the present invention is to detect a developer and a recording medium, which can greatly reduce the cost by reducing the number of parts and simplifying the assembly, and can contribute to downsizing of the image forming apparatus main body by reducing the number of parts. An object of the present invention is to provide a light guide member that holds the means in a compact manner.

  Another object of the present invention is to provide a process cartridge in which such a light guide member is mounted, and an image forming apparatus in which the process cartridge can be easily attached and detached.

  In order to achieve the above object, a typical light guide member of the present invention is an electrophotographic image forming apparatus for forming an image on a recording medium, wherein the recording medium is conveyed, and a first light emitting element. A first light receiving element for receiving the first detection light emitted from the first light emitting element, detecting the presence or absence of the recording medium in the transport path, a second light emitting element, and the second light emitting element The first and second detection lights provided in a developer container for containing a developer used in an electrophotographic image forming apparatus having a second light receiving element that receives second detection light emitted from A light guide member for guiding the light to the first and second light receiving elements, a first incident portion and an emission portion where the first detection light enters and exits, and a second where the second detection light enters and exits. Between the incident part and the outgoing part of the second and the second incident part and the outgoing part A recess having a notch shape provided at a position intersecting the optical path of the second detection light, the recess into which the developer enters in order to detect the amount of the developer in the developer container. It is what.

  According to the light guide member of the present invention, the parts for guiding the detection light from the light emitting element for detecting the recording medium (sheet) and the developer (toner) are gathered into one instead of being separately provided. Can be reduced, and assembly can be facilitated to reduce costs. Further, the space can be saved by the small number of parts, and the enlargement of the apparatus can be suppressed.

  Hereinafter, preferred embodiments of a light guide member, a process cartridge, and an electrophotographic image forming apparatus to / from which they are attached will be described in detail with reference to the drawings.

(Image forming device)
FIG. 1 shows a laser beam printer which is a specific example of an image forming apparatus for forming a color image by electrophotography. A process cartridge can be attached to and detached from the printer main body 100, and an electrophotographic photosensitive member (photosensitive drum) 1 which is a drum-shaped image carrier that rotates at a constant speed is mounted in the process cartridge. When it is determined that the photosensitive drum 1 has reached the end of its life, the user can replace the photosensitive drum 1 by himself / herself. Further, a cleaning container 61 (to be described later) constituting the drum unit 6 is provided in the process cartridge along the photosensitive drum 1 so that toner remaining on the photosensitive drum 1 is removed and stored in the cleaning container 61. It has become. Accordingly, the user can replace the photosensitive drum 1 or the cleaning container 61 in accordance with the signal that the full toner has been detected in accordance with the time when the removed toner is full in the cleaning container 61.

  Therefore, the drum surface of the photosensitive drum 1 is uniformly charged by the charging unit 2. A latent image is formed by irradiating the charged drum surface of the photosensitive drum 1 with laser light corresponding to image information from an exposure means (not shown). This latent image is represented by, for example, four developing devices 4a, 4b, 4c, 4d corresponding to four colors of Y (yellow), M (magenta), C (cyan), and K (black) (hereinafter referred to as “1”). Develop in order. The developed image formed on the photosensitive drum 1 is sequentially transferred to the intermediate transfer belt 5 so that a color image is formed. This color image is transferred from the intermediate transfer belt 5 to a sheet S such as a recording sheet or an OHP sheet which is a recording medium conveyed by the conveying unit 12 from the feeding unit 16. The transferred sheet S is sent to the fixing device 20, where the color image is fixed, and then discharged to the discharge unit 24 on the upper surface of the image forming apparatus main body. The operation of each of the above parts is as follows.

  The latent image formed on the photosensitive drum 1 is visualized as a toner image using a toner by the developing device 4 and transferred to the intermediate transfer belt 5.

  The intermediate transfer member 5 is transferred by superimposing the toner images developed by the developing devices on the four color images when forming the color image. For this reason, the intermediate transfer belt 5 rotates in the counterclockwise direction in FIG. 1 in synchronization with the peripheral speed of the photosensitive drum 1. The intermediate transfer member belt 5 that has received the toner image transfer on the sheet S simultaneously transfers the toner images of the respective colors on the intermediate transfer member 5 onto the sheet S by a transfer roller 13 as a transfer means to which a voltage is applied.

  After the toner image is transferred to the intermediate transfer belt 5, the toner remaining on the surface of the photosensitive drum 1 is removed by the cleaning blade 62. The removed residual toner is stored in the cleaning container 61. The amount of toner in the cleaning container 61 together with the remaining toner is detected by a toner detection means to be described later, and it is determined based on the detection signal whether the toner in the cleaning container is full or the necessary amount is present. It has become.

  On the other hand, as shown in FIG. 1 and FIG. 2 in which a part thereof is enlarged, the conveying means for conveying the sheet S is constituted by the following members and arranged along the conveying path. It has a cassette 17 on which sheets S are stacked and stored, and a feeding roller 18 that feeds the sheets S one by one. Further, conveyance rollers 12a and 12b and a registration roller 19 are arranged along the conveyance path, and a sheet conveyance unit is configured by a discharge roller 23 that discharges the sheet S that has undergone fixing processing after image formation. That is, at the time of image formation, the feeding roller 18 rotates according to the image forming operation, and separates and feeds the sheets S in the cassette 17 one by one. The sheet S sent out from the cassette 17 is conveyed toward the registration roller 19. The registration roller 19 abuts the leading end of the conveyed sheet S, and temporarily stops the sheet S in order to correct the skew of the sheet S. Such a non-rotating operation and a rotating operation for conveying the sheet S toward the intermediate transfer member 5 are performed in a predetermined sequence, and a color image is obtained by aligning the image in the next transfer step with the sheet S. Is transcribed.

  Since the sheet S is temporarily stopped by the registration roller 19, the sheet detection unit of the present embodiment is provided at a convenient position of the main body of the image forming apparatus in order to appropriately set the conveyance timing between the preceding sheet and the subsequent sheet S. Has been placed.

  The sheet S on which the color image has been transferred is sent to the fixing device 20 where it is heated and pressed to fix the toner image on the sheet S. The fixing device 20 includes fixing rollers 21a and 21b for heating the sheet S, and a pressure roller (not shown) for pressing the sheet S against the fixing rollers 21a and 21b. Each of the fixing rollers 21a and 21b has a heater therein and is driven to rotate. The sheet S on which the toner image is fixed is discharged to the discharge unit 24 by the discharge roller 23 of the sheet conveying unit.

(Light guide member: first embodiment)
Next, a description will be given of the light guide member of the present embodiment that collectively holds the portions for guiding the detection light by the sheet detection unit and the toner detection unit.

  3 and 4 show sheet detection means. A cleaning container (developer storage container) 61 is disposed on the other side of the printer main body 100 on the other side facing the frame 30 across the conveyance path for conveying the sheet S. In this case, the cleaning container 61 is attached to and detached from the image forming apparatus main body while being attached to the process cartridge.

  A first light emitting element (light emitting means) 90a and a first light receiving element (light receiving means) 91a are disposed on the substrate provided in the frame 30. The first detection light 76a emitted from the first light emitting element 90a enters the light guide member 71 of the present embodiment provided in the cleaning container 61 from the first incident portion 72a. The first detection light 76a is guided by being reflected by the first and second reflection surfaces 74a and 74b. That is, when the first detection light 76a is incident on the first incident portion 72a, the light is reflected and guided by the first reflecting surface 74a, and further reflected by the second reflecting surface 74b and led to the first emission. Injected from the portion 73a. That is, the first detection light 76a from the first light emitting element 90a is received by the light guide member 71 on the other side of the transport path, reflected and guided back, and received by the first light receiving element 91a. By sending and receiving the first detection light 76a across the conveyance path by such incident and emission, it is detected whether or not the sheet S has passed through the conveyance path, and the presence or absence of the sheet S is determined.

  3 and 4, the toner detection unit is configured by arranging a second light emitting element 90 b and a second light receiving element 91 b on the substrate of the frame 30. In FIG. 3, the second detection light 76 b emitted from the first light emitting element 90 b is incident on the second incident portion 72 b of the light guide member 71 provided in the cleaning container 61. The second detection light 76b is guided by being reflected by the third and fourth reflecting surfaces 74c and 74d. That is, when the second detection light 76b is incident from the second incident portion 72b, it is reflected and guided by the third reflecting surface 74c, traverses the recess 75 provided in the notch shape in the light guide member 71, and the fourth The light is reflected from the reflecting surface 74d and is emitted from the second emitting portion 73b. As can be seen so far, the first reflecting surface 74a and the third reflecting surface 74c are provided on the same inclined surface behind the light guide member 71, and the second reflecting surface 74b and the fourth reflecting surface 74d are also provided. Further, it is provided on the same surface of the rear inclined surface.

  Incidentally, the toner remaining on the electrophotographic photosensitive member, that is, the photosensitive drum 1 is removed and stored in the cleaning container 61. Then, if the removed toner enters and stays in the recess 75 provided in the light guide member 71, the second detection light 76b is blocked by the retained removed toner. Due to such light shielding, the second detection light 76b does not reach the second light receiving element 91b. By detecting this, it is determined whether the toner in the cleaning container 61 is full or has reached a set amount, such as whether or not the required amount remains.

  As understood from the above, according to the first embodiment, the sheet S and the detection light for detecting the remaining amount of toner are reflected and guided to the cleaning container 61 as the developer container. In this structure, the members are held together in one light guide member 71. That is, the first and second light emitting elements 90a and 90b and the first and second light receiving elements 91a and 92b are made to correspond to the light guide member 71, and one light guide member 71 is used to transmit and receive the first and second detection lights. As intervening. As a result, the size of the image forming apparatus can be reduced, and at least the number of light guide members can be reduced as compared to the conventional case. The space for mounting components can be greatly reduced, which contributes to downsizing of the main body of the image forming apparatus.

  Note that, as in the first embodiment, it is detected whether the amount of toner in the cleaning container 61 is full or has reached the required amount. That is, the toner stored in the cleaning container 61 is the toner remaining on the surface of the photosensitive drum 1 and is removed and stored by the cleaning member 62. However, the present invention is not limited to the detection of the amount of removed toner in the cleaning container 61. A developing container provided in each of the four developing devices 4a, 4b, 4c, and 4d corresponding to the Y, M, C, and K colors is referred to as a “developer container”, and is applied to detection of toner fullness inside the developing container. Of course, it is possible.

(Light guide member: second embodiment)
FIG. 5 shows a light guide member 71 according to the second embodiment. In the light guide member 71, first and second detection light beams 76a and 76b irradiated from first and second light emitting elements (not shown) at an angle are incident from the first and second incident portions 72a and 72b. The first and second detection lights 76 a and 76 b are guided by being reflected by the reflecting surface 74, which is the back surface of the light guide member 71, and are angled from the first and second emission portions 73 a and 73 b provided on the light guide member 71. It is injected with. As in the first embodiment, the first detection light 76a can be used for sheet detection, and the second detection light 76b can be used for toner detection. In the light guide member 71 of the second embodiment, the concave portion 75 can be provided at a position that intersects the optical path of the second detection light 76b for detecting the presence or absence of toner.

(Light guide member: Third embodiment)
FIG. 6 shows a light guide member 71 according to the third embodiment. In this case, the second detection light 76 b emitted from the second light emitting element (not shown) is incident on the second incident portion 72 b of the light guide member 71 on the cleaning container 61 side, and the reflective portion provided on the light guide member 71. The light is reflected by the reflection surface 92 and guided. The reflected second detection light 76b is emitted from the second emission part 73b and received by a second light receiving element (not shown). As can be seen from FIG. 6, the second incident portion 72 b and the second emitting portion 73 b are provided to share the same portion of the light guide member 71. Also in this case, the light guide member 71 can be provided with a notch-shaped recess 75 at a position intersecting with the optical path of the second detection light 76b for detecting the presence or absence of toner.

  As mentioned above, although several embodiment was demonstrated about the common detection apparatus of this invention, other embodiment, an application example, a modification, and those combinations are possible within the range which does not deviate from the main point of this invention.

The figure which shows a laser beam printer as a specific example of the image forming apparatus with which the light guide member which concerns on this invention was mounted | worn. The figure which shows the conveyance system in the laser beam printer. The figure which shows the light guide member by 1st Embodiment. The figure which shows the function of the light guide member of the 1st embodiment in detail. The figure which shows the light guide member by 2nd Embodiment. The figure which shows the light guide member by 3rd Embodiment.

Explanation of symbols

1 Photosensitive drum (electrophotographic photosensitive member)
2 Charging means 4a, 4b to developing device 5 intermediate transfer belt 6 drum unit (cleaning device)
DESCRIPTION OF SYMBOLS 10 Rotary unit 11 Intermediate transfer belt 12 Conveyance roller 13 Transfer roller 16 Feed part 17 Feed cassette 18 Feed roller 19 Registration roller 20 Fixing device 21a, 21b Fixing roller 23 Discharge roller 24 Discharge part 30 Frame 41a of image forming apparatus main body , 41b to developing container 45a, 45b to developing roller
DESCRIPTION OF SYMBOLS 50 Toner supply roller 60 Cleaning means 61 Cleaning container 62 Cleaning blade 71 Light guide member 72a 1st incident part 72b 2nd incident part 73a 1st output part 73b 2nd output part 74 Reflective surface 74a 1st reflective surface 74b Second reflecting surface 74c Third reflecting surface 74d Fourth reflecting surface 75 Recessed portion 76a First detection light 76b Second detection light 90a First light emitting element (light emitting means)
90b Second light emitting element (light emitting means)
91a First light receiving element (light receiving means)
91b Second light receiving element (light receiving means)
92 Reflecting section 100 Image forming apparatus S Sheet (recording medium)
T Toner (Developer)

Claims (7)

An electrophotographic image forming apparatus for forming an image on a recording medium, wherein the recording medium is conveyed, a first light emitting element, and first detection light emitted from the first light emitting element are received. An electron having a first light receiving element for detecting the presence or absence of the recording medium in the transport path, a second light emitting element, and a second light receiving element for receiving a second detection light emitted from the second light emitting element. A light guide member used in a photographic image forming apparatus for guiding the first and second detection lights to a first and second light receiving elements provided in a developer container that contains a developer;
A first incident part and an emission part into which the first detection light enters and exits;
A second incident part and an emission part into which the second detection light enters and exits;
In order to detect the amount of developer in the developer containing container, a notch-shaped recess provided at a position intersecting the optical path of the second detection light between the second incident portion and the emitting portion. A recess into which the developer enters,
A light guide member characterized by comprising: The light guide member is
Having at least one reflecting surface for guiding the first detection light from the first incident portion to the emitting portion, and having at least one reflecting surface for guiding the second detection light from the second incident portion to the emitting portion. The light guide member according to claim 1, wherein the light guide member is provided. When the reflective surface for guiding the first detection light is composed of first and second reflective surfaces, and the reflective surface for guiding the second detection light is composed of third and fourth reflective surfaces,
The said 1st reflective surface and the said 3rd reflective surface were provided in the same surface, and the said 2nd reflective surface and the said 4th reflective surface were provided in the same surface, The Claim 2 characterized by the above-mentioned. Light guide member. An electrophotographic image forming apparatus for forming an image on a recording medium, wherein the recording medium is conveyed, a first light emitting element, and first detection light emitted from the first light emitting element are received. An electron having a first light receiving element for detecting the presence or absence of the recording medium in the transport path, a second light emitting element, and a second light receiving element for receiving a second detection light emitted from the second light emitting element. A process cartridge that is detachable from a photographic image forming apparatus,
An electrophotographic photoreceptor;
A cleaning member for removing the developer from the surface of the electrophotographic photoreceptor;
A developer storage container for storing the developer removed by the cleaning member;
A light guide member for guiding the first and second detection lights provided in the developer container to the first and second light receiving elements,
A first incident part and an emission part into which the first detection light enters and exits;
A second incident part and an emission part into which the second detection light enters and exits;
In order to detect the amount of developer in the developer containing container, a notch-shaped recess provided at a position intersecting the optical path of the second detection light between the second incident portion and the emitting portion. A recess into which the developer enters,
A light guide member comprising:
A process cartridge characterized by having The light guide member is
Having at least one reflecting surface for guiding the first detection light from the first incident portion to the emitting portion, and having at least one reflecting surface for guiding the second detection light from the second incident portion to the emitting portion. The process cartridge according to claim 4, wherein the process cartridge is provided. When the reflective surface for guiding the first detection light is composed of first and second reflective surfaces, and the reflective surface for guiding the second detection light is composed of third and fourth reflective surfaces,
6. The first reflecting surface and the third reflecting surface are provided on the same surface, and the second reflecting surface and the fourth reflecting surface are provided on the same surface. Process cartridge. An electrophotographic image forming apparatus for forming an image on a recording medium,
a) a conveyance path through which the recording medium is conveyed;
b) a first light emitting element;
c) a first light receiving element for receiving the first detection light emitted from the first light emitting element for detecting the presence or absence of the recording medium in the transport path;
d) a second light emitting element;
e) a second light receiving element that receives the second detection light emitted from the second light emitting element;
f) a process cartridge detachably mounted on the electrophotographic image forming apparatus,
An electrophotographic photoreceptor;
A cleaning member for removing the developer from the surface of the electrophotographic photoreceptor;
A developer storage container for storing the developer removed by the cleaning member;
A light guide member for guiding the first and second detection lights provided in the developer container to the first and second light receiving elements, wherein the first detection light is incident / exited. A position that intersects the optical path of the second detection light between the incidence part and the emission part, the second incidence part and the emission part where the second detection light enters and exits, and the second incidence part and the emission part A light guide member having a recess into which the developer enters in order to detect the amount of developer in the developer container,
A process cartridge having
An electrophotographic image forming apparatus comprising:

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