JP2010282086A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that prevents displacement of a lens even in the case that a substrate bends. <P>SOLUTION: The image forming apparatus includes: a body frame 2; a cartridge (process cartridge 5) attachable to or detachable from the body frame 2; a substrate 80 for supplying power to the cartridge via biasing member (coil springs 81 and 82); a light emitting element 71 attached to the substrate 80; and a lens 72 disposed opposite to the light emitting element 71 in the direction of an optical axis. The lens 72 is fixed to only the body frame 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus including a light emitting element fixed to a main body frame.

  2. Description of the Related Art Conventionally, there is known an image forming apparatus including a process cartridge that is detachably mounted on a main body frame, and an optical sensor that detects the remaining amount of toner through light through a toner storage portion of the process cartridge (Patent Document 1) reference). In this technique, the optical sensor includes a light emitter that emits light and a light receiver that receives light emitted from the light emitter.

  The light emitter includes a light emitting element provided on a small substrate and a bottomed cylindrical holder in which a lens is integrally formed on a bottom wall, and the opening side of the holder is fixed to the substrate. . And this light-emitting device is being fixed to the main body frame because the outer peripheral part of the holder is engage | inserted by the hole formed in the main body frame.

JP 2000-258984 A

  By the way, in the image forming apparatus, a large-sized substrate for mainly supplying power to the process cartridge is separately provided so as to overlap the above-described light emitting element substrate. As a result, there has been a problem that the apparatus becomes large in the direction in which the two substrates overlap (opposite directions).

  To solve this problem, it is conceivable to integrate a small substrate and a large substrate. However, a large substrate may be bent by applying an urging force from a terminal having a spring property for supplying power to the process cartridge. When such a large substrate is bent, the substrate A load is applied to the holder that is fixed across the main body frame, and the position of the holder (lens) may shift.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can prevent lens displacement even when a substrate is bent.

  The present invention that solves the above problems includes a main body frame, a cartridge that can be attached to and detached from the main body frame, a substrate that supplies power to the cartridge via a biasing member, and a light-emitting element that is attached to the substrate. An image forming apparatus comprising: a lens disposed opposite to the light emitting element in an optical axis direction, wherein the lens is fixed only to the main body frame.

  According to the present invention, since the lens is fixed only to the main body frame, even if the substrate is bent by the urging force from the urging member, the stress due to the bending of the substrate is not applied to the lens and the surrounding components. Therefore, it is possible to prevent the lens from being displaced. Even if light is emitted obliquely from the light emitting element due to the bending of the substrate, the lens position is constant, so that the light emitted obliquely travels straight in the direction in which the lens faces after passing through the lens. In addition, toner detection can be performed satisfactorily.

  According to the present invention, since the lens is fixed only to the main body frame, even when the substrate is bent by the biasing force from the biasing member, it is possible to prevent the lens from being displaced.

1 is a cross-sectional view illustrating a laser printer as an example of an image forming apparatus according to an embodiment of the present invention. It is explanatory drawing which shows the structure around an optical sensor. It is explanatory drawing which shows the state which the board | substrate bent.

<Schematic configuration of laser printer>
Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, the direction will be described with reference to the user who uses the laser printer. That is, the left side in FIG. 1 is “front”, the right side is “rear”, the front side is “right”, and the back side is “left”. Also, the vertical direction in FIG.

  As shown in FIG. 1, the laser printer 1 mainly includes a main body frame 2 that includes a paper feed unit 3, an exposure device 4, a process cartridge 5 as an example of a cartridge, and a fixing device 6.

  The paper feed unit 3 is provided in the lower part of the main body frame 2, and includes a paper feed tray 31 that accommodates the paper P, a paper pressing plate 32 that lifts the front side of the paper P, a lift lever 33, a pickup roller 34, A roller 35, a paper feed pad 36, and a registration roller 37 are mainly provided. The paper P in the paper feed tray 31 is brought to the pickup roller 34 by the lift lever 33 and the paper pressing plate 32 and is sent out by the pickup roller 34. The fed paper P is separated one by one by the paper feed roller 35 and the paper feed pad 36, passes through the registration roller 37, and is conveyed toward the photosensitive drum 51 and the transfer roller 53.

  The exposure apparatus 4 is provided at an upper portion in the main body frame 2 and mainly includes a laser light emitting unit (not shown), a polygon mirror 41 that is rotationally driven, lenses 42 and 43, and reflecting mirrors 44 and 45. Laser light based on image data emitted from the laser light emitting unit is irradiated on the surface of the photosensitive drum 51 by high-speed scanning through a path indicated by a chain line.

  The process cartridge 5 is disposed below the exposure device 4 and is configured to be detachably attached to the main body frame 2 through an opening formed when the front cover 21 provided on the main body frame 2 is opened. The process cartridge 5 includes a photoconductor cartridge 5A and a developing cartridge 5B.

  The photoreceptor cartridge 5A mainly includes a photoreceptor drum 51, a charger 52, and a transfer roller 53 in a photoreceptor frame 50A. The developing cartridge 5B is configured to be detachably attached to the photoreceptor cartridge 5A, and a developing roller 54, a supply roller 55, and a layer thickness regulating blade 56 are mainly provided in the developing frame 50B. And a toner storage chamber 58 for storing toner.

  In the process cartridge 5, the surface of the photosensitive drum 51 is uniformly charged by the charger 52 and then exposed by high-speed scanning of the laser light from the exposure device 4, whereby image data is transferred onto the photosensitive drum 51. An electrostatic latent image based on is formed. The toner in the toner storage chamber 58 is supplied to the developing roller 54 via the supply roller 55 and enters between the developing roller 54 and the layer thickness regulating blade 56 so as to form a thin layer having a constant thickness. Supported on.

  The toner carried on the developing roller 54 is supplied from the developing roller 54 to the electrostatic latent image formed on the photosensitive drum 51. As a result, the electrostatic latent image is visualized and a toner image is formed on the photosensitive drum 51. Thereafter, the sheet P is conveyed between the photosensitive drum 51 and the transfer roller 53, whereby the toner image on the photosensitive drum 51 is transferred onto the sheet P.

  The fixing device 6 is provided behind the process cartridge 5, and mainly includes a heating roller 61 and a pressure roller 62 that sandwiches the paper P between the heating roller 61. The toner image transferred onto the paper P is thermally fixed by the paper P being conveyed between the heating roller 61 and the pressure roller 62. The sheet P on which the toner image is thermally fixed is conveyed from the fixing device 6 to the discharge path 23 and is discharged from the discharge path 23 onto the discharge tray 22 by the discharge roller 24.

<Structure for detecting the remaining amount of toner>
Next, a structure for detecting the remaining amount of toner in the process cartridge 5 will be described.

  As shown in FIG. 1, a pair of light transmission windows 59 for transmitting light from an optical sensor 70 (see FIG. 2), which will be described later, are formed on both the left and right walls forming the toner storage chamber 58 of the process cartridge 5. Is provided.

  As shown in FIG. 2, the optical sensor 70 includes a light emitting element 71, a lens 72, and a light receiver 73.

  The light emitting element 71 is an element that emits light toward the pair of light transmission windows 59 of the process cartridge 5, and is attached to the substrate 80. The substrate 80 supplies power to the light emitting element 71 and also supplies power to the process cartridge 5 (charger 52 and the like) via coil springs 81 and 82 as an example of an urging member and a relay electrode 83.

  Specifically, the substrate 80 is fixed to the side panel 25 which is one of a plurality of components constituting the main body frame 2 by fastening screws 84. A coil spring 81 is disposed between the substrate 80 and the side panel 25 in a compressed state. Therefore, a biasing force is always applied to the substrate 80 from the coil spring 81 regardless of whether the process cartridge 5 is attached or detached.

  Further, a relay electrode 83 formed of a metal plate or the like is disposed between the coil spring 81 and the side panel 25. The relay electrode 83 is disposed inside the process cartridge (from the hole 25A formed in the side panel 25). 5 side). A coil spring 82 fixed to the relay electrode 83 is disposed in the hole 25A, and the tip of the coil spring 82 comes into contact with the terminal 5C of the process cartridge 5, whereby electric power is supplied from the substrate 80 to the process cartridge 5. Is supplied.

  The lens 72 is fitted and fixed in a hole 25 </ b> B formed at an appropriate position of the side panel 25 so as to be disposed opposite to the light emitting element 71 in the optical axis direction. That is, the lens 72 is not fixed so as to straddle the side panel 25 and the substrate 80 as in the prior art, but is fixed only to the side panel 25.

  The light receiver 73 includes a lens (not shown) that collects the light that has passed through the pair of light transmission windows 59 and a light receiving element (not shown) that receives the light collected by the lens. A control device (not shown) calculates the remaining amount of toner in the process cartridge 5 based on the amount of light received by the light receiver 73.

  Since the optical sensor 70, particularly the periphery of the light emitting element 71 is configured in this way, even when the substrate 80 is bent by the biasing force of the coil spring 81 as shown in FIG. Since the lens 72 is separately fixed to the side panel 25 and the substrate 80, a load is not applied to the light emitting element 71, the lens 72, and the like. Further, the light emitting element 71 is tilted from the original position due to the bending deformation of the substrate 80, but the lens 72 is held in a fixed posture with respect to the side panel 25, and thus the light emitting element 71 is emitted obliquely from the light emitting element 71. The light travels straight along the optical axis direction of the lens 72 by being appropriately refracted by the lens 72. As a result, even when the substrate 80 is bent, the light from the light emitting element 71 can be received well by the light receiver 73 and the remaining amount of toner can be detected well.

According to the above, the following effects can be obtained in the present embodiment.
Since the light emitting element 71 and the lens 72 are separately fixed to the side panel 25 and the substrate 80, even if the substrate 80 is bent, the displacement of the lens 72 can be prevented.

  Since both the lens 72 and the substrate 80 are attached to the side panel 25 which is one of a plurality of components constituting the main body frame 2, the positional relationship between the lens 72 and the light emitting element 71 can be accurately matched. it can.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the above embodiment, the present invention is applied to the structure around the light emitting element 71 of the optical sensor 70 for detecting the remaining amount of toner. However, the present invention is not limited to this, and for example, the surface of a charged photosensitive drum is used. You may apply this invention to the structure around the light emitting element for static elimination which radiate | emits the light for static elimination.

  In the above embodiment, the process cartridge 5 that can be separated into the photosensitive cartridge 5A and the developing cartridge 5B is used as the cartridge. However, the present invention is not limited to this, and for example, the photosensitive cartridge and the developing cartridge are integrally formed. May be used.

In the above-described embodiment, the coil springs 81 and 82 are employed as the urging member.
In the above embodiment, the present invention is applied to the laser printer 1. However, the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as a copying machine and a multifunction machine.

DESCRIPTION OF SYMBOLS 1 Laser printer 2 Main body frame 5 Process cartridge 5A Photosensitive cartridge 5B Developing cartridge 5C Terminal 25 Side panel 59 Light transmission window 70 Optical sensor 71 Light emitting element 72 Lens 73 Light receiver 80 Substrate 81 Coil spring 82 Coil spring 83 Relay electrode

Claims (2)

Body frame,
A cartridge removable from the main body frame;
A substrate for supplying electric power to the cartridge via an urging member;
A light emitting element attached to the substrate;
A lens disposed opposite to the light emitting element in the optical axis direction, and an image forming apparatus comprising:
The image forming apparatus, wherein the lens is fixed only to the main body frame.   The image forming apparatus according to claim 1, wherein both the substrate and the lens are attached to one of a plurality of components constituting the main body frame.

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