JP5383879B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus having an electrophotographic process.

  Patent Document 1 discloses a technique for preventing contamination / cleaning of a dustproof transmission member (dustproof glass) in an image forming apparatus. This is because the dust-proof glass on the optical unit is shielded and interlocked with the opening operation of the opening portion that requires opening when the process cartridge having the image forming means detachable from the image forming apparatus is exchanged. It is to be cleaned.

  With this configuration, it is possible to prevent dust and toner generated during the process cartridge replacement operation from adhering to the dust-proof glass. Further, it is possible to clean dust and toner stains accumulated on the dust-proof glass before the process cartridge is replaced.

JP 2004-085899 A

  The present invention is a further development of the conventional configuration described above.

  That is, normally, during image formation, toner scattering from the developing roller during development, toner scattering at the time of supplying toner to the developing device, and the like slightly occur. Also, when the photosensitive drum, which is an image carrier, is scraped off the surface, or when the photosensitive drum and the developing device are separated and contacted for the purpose of preventing the deterioration of the developing device, the toner is slightly dropped or scattered due to the impact of the operation. Arise. Further, paper dust due to the conveyance of the recording paper, dust contained in the air, and the like accumulate in the apparatus as dust.

  While these toners and dust are treated with a dustproof filter or the like outside the machine, they slightly float inside the machine. As a result, toner and dust adhere to the dust-proof glass even in situations other than the process cartridge replacement operation.

  When such toner or dust adheres to the dust-proof glass, the laser beam emitted from the dust-proof glass is partially shielded to cause deterioration of the printed image and affect the optical characteristics. In particular, when the optical unit is provided in the lower part of the apparatus main body and the emission opening part is provided in the upward direction, there is a strong risk of adhesion of dirt to the dustproof glass.

An object of the present invention, at the contact and the development contact and separation can be images forming apparatus for the separation of the photosensitive drum and the developing roller, by using the separation means, transmission member, adhesion of the toner to the exposure means The purpose is to prevent.

In order to achieve the above object, a typical configuration of an image forming apparatus according to the present invention is an image forming apparatus including an apparatus main body and a process cartridge that can be attached to and detached from the apparatus main body. a photosensitive drum unit having a drum, said a developing unit having a developing roller for developing an electrostatic latent image formed on the photosensitive drum, the photosensitive member engages drum unit and binding, relative to the photosensitive drum, A contact position for bringing the developing roller into contact with the photosensitive drum; and a developing unit capable of taking a separation position for separating the developing roller from the photosensitive drum. And an exposure unit that forms an electrostatic latent image by irradiating with a first position where the developing unit is disposed at the contact position during image formation. A separation unit located at a second position for disposing the development unit at the separation position during non-image formation, and a shielding member movable in conjunction with the operation of the separation unit. When taking the position, the light path through which the light passes is opened, and when the developing unit takes the separated position, a shielding member capable of shielding the light path and receiving the developer, and the shielding member are When the process cartridge is mounted on the apparatus main body in a state where the optical path is shielded , the developing unit is guided from the contact position to the separated position while being guided by the mounting operation of the process cartridge while guiding the developing unit. is moved, has a guide portion provided on the shield member, when mounting the said process cartridge, said spacing means is in said second position, Serial shielding member, characterized in that a position shielded from the optical path.

According to the present invention, the images forming apparatus detachably mountable process cartridge having a developing unit which is movable in position for position and spacing of performing the contact of the photosensitive drum and the developing roller, the process cartridge when mounted and non It is possible to suppress the toner from adhering to the exposure means and the optical path during image formation .

1 is a schematic sectional view of an image forming apparatus according to Embodiment 1. FIG. FIG. 2 is a partially enlarged view of FIG. 1. FIG. 2 is a partially enlarged view of FIG. 1. FIG. 6 is an explanatory diagram when a process cartridge is not mounted. It is a perspective view of the separation / contact switching mechanism of the developing device. (A), (b), and (c) are schematic cross-sectional views of the image forming unit when the image forming apparatus is on standby, in full color mode, and in mono color mode, respectively. It is a state diagram of a process cartridge at the time of development separation. 2A and 2B are schematic cross-sectional views of an image forming unit of an image forming apparatus in which a cleaning member is provided in a process cartridge. FIG. 6 is a schematic cross-sectional view of an image forming apparatus according to Embodiment 2. FIG. It is a detailed view of a separation / contact switching mechanism. It is a cam diagram which showed the relationship between a separation cam and a cleaning shielding member position. FIG. 10 is a detailed view of a rotating cam link mechanism of a developing contact / separation mechanism according to a third embodiment. (A), (b), and (c) are schematic cross-sectional views of the image forming unit when the image forming apparatus is on standby, in full color mode, and in mono color mode, respectively. It is the detail which looked at the rotation cam link mechanism part at the time of the development contact of the development contact separation mechanism part concerning a 3rd example from the upper surface. FIG. 10 is a detailed view of a rotating cam link mechanism when a developing contact / separation mechanism according to a third embodiment is separated from the upper surface. 6 is a schematic cross-sectional view of an image forming apparatus according to Embodiment 4. FIG. 6 is a partial cross-sectional view of an image forming apparatus according to Embodiment 4. FIG. FIG. 9 is an enlarged view of a developing separation unit and a transmissive member according to Embodiment 4. 6 is a partial cross-sectional view of an image forming apparatus according to Embodiment 4. FIG. FIG. 9 is an enlarged view of a developing separation unit and a transmissive member according to Embodiment 4.

  Hereinafter, embodiments of an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Example 1
FIG. 1 is a schematic cross-sectional view of an image forming apparatus 100 in this embodiment, FIG. 2 is a partially enlarged view thereof, and FIG. 3 is an enlarged view of one process cartridge portion in an image forming portion.

  The image forming apparatus 100 is a four-color full-color laser printer using an electrophotographic process, and records based on an electrical image signal input from an external host device (not shown) such as a personal computer, an image reader, or a facsimile. Image formation on the medium S is executed.

[Overall Configuration of Image Forming Apparatus]
Referring mainly to FIG. 1, the image forming apparatus 100 roughly includes an image forming unit A, a paper feeding / conveying unit B, and a fixing unit C. The image forming unit A is located at the center in the image forming apparatus. The sheet feeding / conveying section B is located from the lower right hand to the upper right hand, and the fixing section C is placed on the uppermost right hand.

(1) Image forming unit A
The image forming unit A is a four-drum / tandem type, and is provided with four first to fourth images that are horizontally arranged from the left side toward the right side, and are rotatable image carriers. A drum-shaped electrophotographic photosensitive member 1 (1a, 1b, 1c, 1d) is provided as a body. This drum-shaped electrophotographic photoreceptor 1 is hereinafter referred to as a photoreceptor drum. The image forming unit includes a charging device 2 (2a, 2b, 2c, and 2d), an exposure device 3, a developing device 4 (4a, 4b, 4c, and 4d) as process units that act on the respective photosensitive drums 1. It has an intermediate transfer unit 5, a cleaning device 6 (6a, 6b, 6c, 6d) and the like.

1) Photosensitive drum 1
Each photoconductor drum 1 is configured by applying an organic photoconductor layer (OPC photoconductor) to an outer peripheral surface of an aluminum cylinder having a diameter of 30 mm, for example. Both ends of the photosensitive drum 1 are rotatably supported by a support member, and a driving force from a driving motor (driving means: not shown) is transmitted to one end of the photosensitive drum 1 in FIG. The motor is rotated clockwise at a predetermined speed.

2) Charging device 2
Each charging device 2 is a charging unit that uniformly charges the peripheral surface of the corresponding photosensitive drum 1 to a predetermined polarity and potential. As the charging device 2, a contact charging type can be used. In this embodiment, the charging member of the charging device 2 is a conductive roller formed in a roller shape. The roller is brought into contact with the surface of the photosensitive drum 1 and a predetermined charging bias voltage is applied to uniformly charge the surface of the photosensitive drum 1 to a predetermined polarity and potential.

3) Exposure apparatus 3
The exposure apparatus 3 is an exposure unit that forms an electrostatic latent image by transmitting light (light image based on image information) to the charged surface of each photosensitive drum 1 through a transmissive member. In this embodiment, the exposure apparatus 3 is a scanner unit (optical unit) that irradiates each photosensitive drum 1 with a laser beam L (La, Lb, Lc, Ld) based on image information. 1 is disposed below 1.

  As shown in FIG. 2, in the scanner unit 3, image light corresponding to an image signal output by a laser diode (not shown) is applied to a polygon mirror 9 that is rotated at high speed by a scanner motor 99. The polygon mirror 9 deflects and scans the irradiated image light. The image light reflected by the mirror 9 is charged via the imaging lens 10 (10a to 10d), the reflection mirror 8 (8a to 8h), the dust-proof glass 30 (30a to 30d) which is a transmission member for dust prevention, and the like. The exposed surface of the photosensitive drum 1 is selectively exposed.

  Thereby, an electrostatic latent image corresponding to the exposure pattern is formed on the surface of each photosensitive drum 1.

4) Development device 4
Each developing device 4 is in contact with the corresponding photosensitive drum 1 and is a developing roller 41 (41a, 41b, 41c) as a developer carrying member that develops the electrostatic latent image formed on the photosensitive drum with the developer. , 41d).

5) Intermediate transfer unit 5
The intermediate transfer unit 5 is disposed above the respective photosensitive drums 1 and is a means for primarily transferring the toner images on the respective photosensitive drums 1 to the intermediate transfer belt 11. 1, the intermediate transfer unit 5 is supported in a horizontal direction between two parallel drive rollers 13 and a tension roller 14 disposed on the right side and the left side in FIG. The endless intermediate transfer belt 11 is provided.

The belt 11 has a driving roller at a speed corresponding to the rotational speed of the photosensitive drum 1 in the counterclockwise direction indicated by an arrow in a state where the descending belt portion is in contact with the upper surface of all the photosensitive drums 1. 13 is circulated and driven. The belt 11 is a flexible endless belt having a thickness of about 150 μm and a circumference of about 700 mm with a volume resistivity of 10 ¹¹ to 10 ¹⁴ Ω · cm, for example.

  Inside the belt 11, primary transfer rollers 12 (12 a, 12 b, 12 c, 12 d) are arranged in parallel at positions facing the respective photosensitive drums 1. A belt portion on the lower side of the belt 11 is sandwiched between each primary transfer roller 12 and each photosensitive drum 1. The contact portions between the photosensitive drums 1 and the belts 11 are primary transfer portions.

  In this embodiment, a negative toner image is formed on each photosensitive drum 1, and a primary transfer bias voltage of a predetermined voltage is applied to the primary transfer roller 12 with a positive polarity that is opposite to the charging polarity of the toner. The As a result, the negative toner image on each photosensitive drum 1 is primarily transferred to the belt 11 in each primary transfer portion.

  A secondary transfer unit 24 that secondarily transfers the toner image on the belt 11 to the recording medium S is disposed on the downstream side in the moving direction of the belt 11 from the primary transfer portion. In the secondary transfer unit 24, a secondary transfer roller 25 is disposed at a position facing the driving roller 13 of the intermediate transfer unit 5 with the belt 11 interposed therebetween.

  A contact portion between the belt 11 and the secondary transfer roller 25 is a secondary transfer portion. The recording medium S is fed to the secondary transfer unit by the paper feeding / conveying unit B, and the secondary transfer unit is nipped and conveyed. The secondary transfer roller 25 is applied with a secondary transfer bias voltage having a predetermined polarity and a positive polarity that is opposite to the charging polarity of the toner. As a result, the toner image primarily transferred to the belt 11 is secondarily transferred to the recording medium S.

  A belt cleaning device 15 for removing toner remaining on the belt 11 after the secondary transfer is disposed at a position facing the tension roller 14 of the intermediate transfer unit 5. The toner removed from the belt 11 by the belt cleaning device 15 passes through the waste toner conveyance path and is collected in the waste toner collection container 26.

6) Cleaning device 6
In this embodiment, each cleaning device 6 (6a, 6b, 6c, 6d) has a cleaning blade that abuts the corresponding photosensitive drum 1 in the counter direction. The cleaning blade scrapes off the toner on the photosensitive drum.

7) Process cartridge 7
In the present embodiment, the first process cartridge 7a is a cartridge in which the first photosensitive drum 1a and a charging device 2a, a developing device 4a, and a cleaning device 6a as process means acting on the first photosensitive drum 1a are integrally provided. Has been. The first process cartridge 7a is detachably attached to the apparatus main body 100A.

  In the second process cartridge 7b, a second photosensitive drum 1b and a charging device 2b, a developing device 4b, and a cleaning device 6b as process means acting on the second photosensitive drum 1b are integrally provided to form a cartridge. The second process cartridge 7b is detachably attached to the apparatus main body 100A.

  In the third process cartridge 7c, a third photosensitive drum 1c and a charging device 2c, a developing device 4c, and a cleaning device 6c as process means acting on the third photosensitive drum 1c are integrally provided to form a cartridge. The third process cartridge 7c is detachably attached to the apparatus main body 100A.

  In the fourth process cartridge 7d, a fourth photosensitive drum 1d and a charging device 2d, a developing device 4d, and a cleaning device 6d as process means acting on the fourth photosensitive drum 1d are integrally provided to form a cartridge. The fourth process cartridge 7d is detachably attached to the apparatus main body 100A.

  Here, the apparatus main body 100A is an image forming apparatus portion obtained by removing the process cartridge 7 (7a, 7b, 7c, 7d) from the image forming apparatus main body 100. In the following description, the longitudinal direction of the process cartridge 7 or its constituent members and other members is the axial direction of the photosensitive drum 1 or a direction parallel to the axial direction.

  The apparatus main body 100A has a mounting mechanism (not shown) for detachably mounting each cartridge 7 so that each cartridge 7 is attached to and detached from the apparatus main body 100A by the mounting mechanism. Each cartridge 7 is held in a state of being fixed to a predetermined positioning portion in a state where the cartridge 7 is mounted on the apparatus main body 100A. The drive output unit on the apparatus main body 100A side is coupled to the drive input unit of the cartridge 7. In addition, the power supply system on the apparatus main body 100 </ b> A side is electrically connected to the electrical contacts of the cartridge 7.

  Each of the first to fourth cartridges 7 has the same configuration except that the color of the developer (toner) contained therein is different. The first cartridge 7a contains a yellow (Y) developer in the developer accommodating portion, and forms a Y developer image on the photosensitive drum 1a. The second cartridge 7b contains magenta (M) developer in the developer containing portion, and forms an M color developer image on the photosensitive drum 1b.

  The third cartridge 7c contains cyan (C) developer in the developer containing portion, and forms a C-color developer image on the photosensitive drum 1c. The fourth cartridge 7d contains black (K) developer in the developer accommodating portion, and forms a K-color developer image on the photosensitive drum 1d.

  Each cartridge 7 includes a photosensitive drum unit 50 (50a, 50b, 50c, 50d) and a developing unit 40 (40a, 40b, 40c, 40d) as shown in FIGS. The photosensitive drum unit 50 includes a photosensitive drum 1, a charging device 2, and a cleaning device 6. The developing unit 40 includes a developing device 4. The photosensitive drum unit 50 and the developing unit 40 are coupled so as to be rotatable about a support shaft 49 (FIG. 3).

  As illustrated in FIG. 3, the developing unit 40 includes a toner container 48 that is a developer container and a developing container 45 that is a developing frame. In the developing container 45, a developing roller 41 is disposed as a developer carrying member that carries and conveys the developer so as to face the photosensitive drum 1. The developer in the toner container 48, that is, the toner, is sent to the toner supply roller 43 by the toner conveyance stirring mechanism 42.

  Next, the toner is applied to the outer periphery of the developing roller 41 by the toner supply roller 43 and the developing blade 44 in pressure contact with the outer periphery of the developing roller 41, and an electric charge is given to the toner. Then, by applying a developing bias to the developing roller 41, the latent image formed on the photosensitive drum 1 is developed into a toner image. The developing roller 41 contacts the photosensitive drum 1 and develops the electrostatic latent image formed on the photosensitive drum 1.

  The developing unit 40 is entirely supported so as to be swingable (rotatable) with respect to the photosensitive drum unit 50 around support shafts 49 provided on bearing members 47 attached to both ends in the longitudinal direction. Has a suspended structure. A pressure spring that applies an elastic force so that the developing unit 40 and the photosensitive drum unit 50 are always urged to rotate about the support shaft 49 in the direction in which the developing roller 41 contacts the photosensitive drum 1. An (elastic member) 54 is provided.

  When the cartridge 7 is in a single state, that is, not attached to the apparatus main body 100A, the developing unit 40 and the photosensitive drum unit 50 are moved by the pressure spring 54 in the direction in which the developing roller 41 comes into contact with the photosensitive drum 1. It is always urged to rotate.

  With each cartridge 7 mounted on the apparatus main body 100A, the photosensitive drum unit 50 is positioned and fixed with respect to the apparatus main body 100A and held. The developing unit 40 can swing around a support shaft 49 with respect to the photosensitive drum unit 50 that is fixedly held.

  Separating bosses 46 (46a, 46b, 46c) which are action receiving portions with which the cams 80 (80a, 80b, 80c, 80d) of the separating means on the apparatus main body 100A side contact the toner container 48 of the developing unit 40 of each cartridge 7. , 46d) are provided integrally. The separating means will be described later.

  In each cartridge 7 mounted on the apparatus main body 100A, the developing unit 40 is rotated by the pressure spring 54 with respect to the photosensitive drum unit 50 so that the developing roller 41 contacts the photosensitive drum 1 during image formation. It has been in a state. 1 to 3 show this state. The laser beam L, which is image light emitted from the scanner unit 3, enters the inside of the cartridge from the bottom up through the clearance passage between the developing unit 40 and the photosensitive drum unit 50, and the lower surface of the photosensitive drum 1. To expose.

  Although not shown, the developing unit 40 includes a toner remaining amount detecting mechanism, and transmits the LED light into the toner container 48 to detect the transmission time and detect the remaining amount of toner. That is, as each cartridge 7 is used for image formation, the developer (toner) contained in the toner container 48 is consumed. Therefore, a toner remaining amount detection mechanism is provided, and the control unit of the image forming apparatus compares the detected remaining amount value with a preset threshold value for cartridge life warning or life warning.

  Then, for a cartridge whose detected remaining amount value is smaller than the threshold value, the display unit (not shown) displays a life warning or a life warning for the cartridge. This prompts the user to prepare a cartridge for replacement, or prompts the user to replace the cartridge to maintain the quality of the output image.

  A shielding member 36 (36a, 36b, 36c) for shielding the slits 16 (16a, 16b, 16c, 16d) for securing image light and an optical path is provided on the upper side (upper surface side) of each dustproof glass 30 of the scanner unit 3. , 36d). Each shielding member 36 is rotatably arranged at a position (FIG. 3) where the slit 16 is opened around the support shaft a (FIG. 3) and a position (FIG. 4) where the slit 16 is shielded.

  This shielding member 36 is a shielding member which is an action receiving portion by a convex portion 38 (38a, 38b, 38c, 38d) disposed downward on the lower surface of the photosensitive drum unit 50 when the cartridge 7 is attached to the apparatus main body 100A. The arm part is pushed down. Thereby, the shielding member 36 is held in the rotational angle posture of FIGS. 1 to 3 with the slit 16 opened around the support shaft a. This rotational angle posture is maintained while the cartridge 7 is mounted on the apparatus main body 100A. By opening the slit 16, an electrostatic latent image can be formed by exposing the photosensitive drum 1.

  Further, when the cartridge 7 is not attached to the apparatus main body 100 </ b> A, the shielding member 36 is not subjected to the depression of the shielding member arm portion by the downward convex portion 38 of the cartridge 7. Therefore, the shielding member 36 is rotated and held in a rotation angle posture in which the slit 16 is shielded around the support shaft a as shown in FIG.

  31 (31 a, 31 b, 31 c, 31 d) is a cleaning member that cleans by rubbing the upper surface of each dustproof glass 30. This will be described later.

(2) Paper feeding / conveying section B
The sheet feeding / conveying section B feeds and conveys the recording medium S to a secondary transfer section that transfers the image on the belt 11 to the recording medium S. The recording medium S such as a plurality of transfer sheets is fed. It is loaded and stored in the cassette 17. During image formation, the paper feed roller 18 (half moon roller) feeds the uppermost recording medium S in the paper feed cassette 17. Then, the leading edge of the recording medium S hits the registration roller pair 19 and is temporarily stopped. As a result, a loop is formed in the recording medium S. After a predetermined loop is formed, the recording medium S is fed to the secondary transfer section by the registration roller pair 19 in synchronization with the rotation of the belt 11 and the image writing position.

(3) Fixing part C
The fixing unit C, that is, the fixing unit 20 fixes the toner images of a plurality of colors transferred to the recording medium S, and heats and pressurizes the recording medium S in contact with the rotating heating roller 21a. A pressure roller 21b is provided.

  A discharge roller pair 23 is provided downstream of the fixing unit 20 in the recording medium conveyance direction, and discharges the recording medium S onto a discharge tray 27 on the upper surface of the image forming apparatus.

  A paper discharge sensor (not shown) is disposed between the fixing unit 20 and the paper discharge roller pair 23 so that the recording medium S can be reliably discharged out of the apparatus or the fixing roller pair 21a and 21b of the fixing unit 20. It is monitoring whether it is wrapped around.

  The recording medium S to which the toner image on the photosensitive drum 1 is transferred is conveyed by the fixing roller pair 21a and 21b when passing through the fixing unit 20, and is given heat and pressure by the fixing roller pair 21a and 21b. As a result, the toner images of a plurality of colors are fixed on the surface of the recording medium S.

(4) Image Forming Operation As the image forming operation, the first to fourth cartridges 7a, 7b, 7c, and 7d are sequentially driven in accordance with the print timing, and the first to fourth cartridges are driven according to the drive. The photosensitive drums 1a, 1b, 1c, and 1d are driven to rotate clockwise. Then, the scanner units 3 corresponding to all the cartridges 7 are driven. By this driving, the charging roller 2 applies a uniform charge to the peripheral surface of the photosensitive drum 1, and the scanner unit 3 exposes the peripheral surface of the photosensitive drum 1 in accordance with an image signal, so that the photosensitive member is exposed. An electrostatic latent image is formed on the drum peripheral surface.

  A developing roller 41 in the developing device 4 forms (develops) a toner image on the circumferential surface of the photosensitive drum by transferring toner to a low potential portion of the electrostatic latent image. The toner images of the respective colors formed on the peripheral surface of the photosensitive drum 1 are primarily transferred onto the belt 11 in synchronization with the image position. At this time, a full color toner image is formed on the belt 11 at the stage where the toner images of all colors are primarily transferred.

  That is, a Y developer image corresponding to the yellow component of the full color image is formed on the drum 1a of the first cartridge 7a. Then, the developer image is primarily transferred onto the belt 11. An M developer image corresponding to the magenta component of the full color image is formed on the drum 1b of the second cartridge 7b. The developer image is primary-transferred superimposed on the Y-color developer image already transferred onto the belt 11.

  A C-color developer image corresponding to the cyan component of the full-color image is formed on the drum 1c of the third cartridge 7c, and the developer image is transferred onto the belt 11 as a Y-color + M-color developer. Superimposed on the image, primary transfer is performed. A K developer image corresponding to the black component of the full-color image is formed on the drum 1d of the fourth cartridge 7d. Then, the developer image is primary-transferred superimposed on the Y color + M color + C color developer image already transferred onto the belt 11. Thus, a four-color full-color unfixed toner image of Y color + M color + C color + K color is synthesized and formed on the belt 113.

  The leading edge of the toner image on the peripheral surface of the belt 11 is rotated and conveyed to a point (secondary transfer portion) between the belt 11 and the secondary transfer roller 25. At this timing, that is, so that the printing start position of the recording medium S coincides with the leading edge of the toner image on the belt 11, the registration roller pair 19 starts to rotate and feeds the recording medium S to the secondary transfer portion.

  While being conveyed in this way, the toner image on the belt 11 is transferred to the recording medium S by an electric field formed between the belt 11 and the secondary transfer roller 25.

  Thereafter, the recording medium S to which the full color toner image is transferred is conveyed from the secondary transfer portion to the fixing unit 20. After the toner image is heat-fixed by the fixing unit 20 on the recording medium S, the recording medium S is placed on the discharge tray 27 on the upper surface of the apparatus main body 100A in a state where the image surface is lowered from the discharge portion by the discharge roller pair 23. Discharged.

[Separation means]
In the apparatus main body 100A, separation means (a separation contact mechanism of the development device 4 with respect to the photosensitive drum 1) for separating and contacting the developing roller 41 and the photosensitive drum 1 is arranged for each cartridge 7 mounted. It is installed. During non-image formation, the developing roller 41 can be separated from the photosensitive drum 1 to reduce the surface layer of the photosensitive drum 1 and the deterioration of the developing roller 41.

  FIG. 5 is a perspective view of the separating means 90. On the lower left side of each cartridge 7 mounted on the apparatus main body 100A, a separating cam 80 (for rotating the developing unit 40 with respect to the photosensitive drum unit 50 in a direction separating the developing roller 41 from the photosensitive drum 1). 80a, 80b, 80c, 80d) are arranged. Reference numeral 81 (81a, 81b, 81c, 81d) denotes a camshaft, and two spaced cams 80 having the same shape and size are disposed in the same phase on the back side and the near side.

  The separation cam 80 moves the separation boss 46, which is an action receiving portion provided in the developing unit 40 of each of the first to fourth cartridges 7, to the left and right. As a result, the developing unit 40 is rotated with respect to the photosensitive drum unit 50 with respect to the photosensitive drum 1 by rotating the developing roller 41 about the support shaft 49 in the direction in which the developing roller 41 is separated from the photosensitive drum 1 and in the abutting direction. Switching between separation and contact of the developing roller 41 is performed. Here, the position of the developing unit 40 when the photosensitive drum 1 and the developing roller 4 contact each other is defined as a contact position, and the position of the developing unit 40 when the photosensitive drum 1 and the developing roller 4 are separated from each other is defined as a separated position. To do.

  The separation cams 80 (80a, 80b, 80c, 80d) are respectively connected to the gear trains 91G / 92 (92a, 92b), 93 (93a, 93b), 94 (94a, 94b) by the stepping motor 91 which is the driving means shown in FIG. , 94c, 94d). The rotation of each separation cam 80 causes the separation boss 46 of the developing unit 40 to move left and right in each cartridge 7, and the position where the developing roller 41 is separated from the photosensitive drum 1 and the developing roller 41 to the photosensitive drum 1. A contact position is created.

  In this embodiment, the following three states 1) to 3) can be selected according to the rotation angle of the separation cam 80.

  State a: As shown in FIG. 6A, with respect to all the first to fourth cartridges 7, the developing roller 41 is moved from the photosensitive drum 1 with the largest radius portion of the separation cam 80 opposed to the separation boss 46. Set to the separated standby state.

  State b: As shown in FIG. 6B, the developing roller 41 is placed on the photosensitive drum 1 with the minimum radius portion of the separation cam 80 facing the separation boss 46 for all of the first to fourth cartridges 7. The full color is brought into contact.

  State c: As shown in FIG. 6C, for the first to third three cartridges 7a, 7b, and 7c of Y color, M color, and C color, the maximum radius portion of the separation cam 80 is set as the separation boss. The developing roller 41 is placed in a standby state in which the developing roller 41 is separated from the photosensitive drum 1. The fourth cartridge 7d of K color is in a monocolor state in which the developing roller 41 is in contact with the photosensitive drum 1 with the minimum radius portion of the separation cam 80 opposed to the separation boss 46.

  In the full color mode, development is performed in the order of the first cartridge 7a (Y color) → the second cartridge 7b (M color) → the third cartridge 7c (C color) → the fourth cartridge 7c (K color). The roller 41 comes into contact with the photosensitive drum 1 and the developing operation is executed.

  After the completion of the developing operation, the developing roller in the order of the first cartridge 7a (Y color) → second cartridge 7b (M color) → third cartridge 7c (C color) → fourth cartridge 7c (K color) 41 moves away from the photosensitive drum 1 to finish printing.

  That is, the separation cams 80a, 80b, 80c between the cartridges so that the contact operation and the separation operation are performed in the order as described above between the first to fourth cartridges 7a, 7b, 7c, 7d. , 80d are shifted in phase.

  Further, a developing clutch (not shown) which is a drive switching means is provided in the driving means of the developing roller 41 so that the rotation / stop of the developing roller 41 can be switched when the photosensitive drum 1 is rotating. In this embodiment, the photosensitive member driving means for driving the photosensitive drums 1 and the developing driving means for driving the developing rollers 41 are a common motor for each process cartridge.

  As a result, it is possible to drive the developing roller 41 only when developing a toner image on the photosensitive drum 1 (at the time of image formation), and then contact the photosensitive drum 1, so that the surface layer of the photosensitive drum 1 can be contacted. , And deterioration of the developing roller 41 is reduced.

[Optical component cleaning mechanism]
Next, a cleaning mechanism for the dust-proof glass 30 in the scanner unit 3 will be described.

  The scanner unit 3 cannot form a high-quality electrostatic latent image on the photosensitive drum 1 when dust or dirt adheres to the optical component. In particular, in the configuration in which the optical means is located below the image forming unit as in the image forming apparatus of the embodiment, the scattered / falling toner from the cartridge 7 is likely to adhere to the dust-proof glass 30. Therefore, the scanner unit 3 is configured by sealing optical components such as the polygon mirror 9, the imaging lens 10, and the reflection mirror 8 in a case, and an exit opening having a dustproof glass 30 attached to the unit is provided. The light irradiation is performed from.

  A cleaning member 31 (31a, 31b, 31c, 31d) for cleaning each dustproof glass 30 (30a, 30b, 30c, 30d) is provided along the optical case on the scanner unit 3 in the apparatus main body 100A. It has been.

  The cleaning member 31 has a long cleaning plate 32 (FIG. 3) arranged so as to cover the upper surface of the slit-shaped dustproof glass 30, and a brush 33 attached to the dustproof glass 30 side of the cleaning plate 32. And is urged toward the dust-proof glass by a pressing spring (not shown). The cleaning member 31 is attached to the optical case in such a manner that the brush 33 can move so as to slide in contact with the dust-proof glass 30, and covers the dust-proof glass 30 at a position where the dust-proof glass 30 is exposed (FIG. 3). It is possible to move between the two positions (FIG. 7).

  Further, positioning bosses 34 (FIGS. 3 and 7) for engaging with the developing units 40 of the corresponding cartridges 7 are provided at both ends of each cleaning member 31 in the longitudinal direction. The positioning boss 34 has a tapered tip so that the developing unit 40 and the positioning boss 34 are always engaged when the cartridge is mounted to the apparatus main body 100A.

  Thus, the dust-proof glass 30 is cleaned in conjunction with the rotation operation of the developing unit 40 with respect to the photosensitive drum unit 50 (separation / contact operation of the developing device) by the separating means 90. That is, the cleaning member 31 moves relative to the dust-proof glass 30 in conjunction with the separation / contact operation of the developing roller 41 with respect to the photosensitive drum 1 to clean the dust-proof glass 30.

  In the above configuration, when the cartridge 7 is attached to the apparatus main body 100A, the separation boss 46 of the developing unit 40 rides on the separation cam 80, and the developing roller 41 and the photosensitive drum 1 are separated. In this state, the cleaning member 31 is engaged with the developing unit 40. At this time, as shown in FIG. 6A and FIG. 7, the cleaning member 31 is positioned so as to contact and cover the upper surface of the dust-proof glass 30.

  Thereafter, when the image forming operation is started by the print signal, all the drive motors are rotated. Next, the motor 91 rotates, and accordingly, the separation cam 80 rotates. The developing unit 40 rotates counterclockwise about the support shaft 49 via the separating boss 46 as the separating cam 80 rotates, and stops at the position where the developing roller 41 and the photosensitive drum 1 come into contact with each other. Then, image formation is started.

  The cleaning member 31 moves in conjunction with the movement of the developing unit 40 via a positioning boss (engagement portion) 34. That is, while cleaning the surface of the dust-proof glass 30 by rubbing with the brush 33, the dust-proof glass 30 moves from the position shown in FIG. 6A and FIG. 7 to the position shown in FIG. At this time, the cleaning member 31 is moved to an open position where the optical path of the laser light L emitted from the scanner unit 3 is opened.

  After the image formation is completed, the motor 91 rotates again, and the separation cam 80 rotates accordingly. The developing unit 40 rotates clockwise around the support shaft 49 via the separating boss 46 as the separating cam 80 rotates, and the developing roller 41 and the photosensitive drum 1 are separated at a predetermined interval. (Fig. 6 (a), Fig. 7). The cleaning member 31 moves to a position that covers the dust-proof glass 30. Thereafter, all the drive motors are stopped and the printing operation is terminated.

  Accordingly, through the above-described process, the dirt of the dust-proof glass 30 is automatically cleaned with the separation / contact operation of the developing device of each cartridge 7, so that the dust-proof glass 30 generated at the time of cartridge replacement or image formation is removed. Image degradation due to dirt can be prevented.

  In this embodiment, along with the separation / contact operation of the developing device by the separation means 90, the dirt on the dust-proof glass 30 is cleaned by simultaneously interlocking the cleaning member 31. In the configuration of the present embodiment, the cleaning member 31 is a shielding member for closing the optical path of the image light irradiated from the scanner unit 3 and the slits provided for securing the optical path. As a result, it is possible to prevent toner scattering / dropping from the image forming means and dust in the apparatus from adhering to the dust-proof glass 30 or the like when the cartridge 7 is replaced or when an image is formed.

  Furthermore, by using the shielding member also as the cleaning member 31, it is possible to both prevent the adhesion of dirt and clean the attached dirt, and it is possible to obtain many effects by preventing the dust-proof glass 30 from being stained.

  Furthermore, in the present embodiment, the cleaning member 31 is configured to clean the dust-proof glass 30 in conjunction with the rotation of the developing unit 40. However, as shown in FIG. The dust-proof glass 30 may be configured to be disposed on the screen. Thereby, it becomes possible to clean the dust-proof glass 30 with the new cleaning member 31 every time the cartridge 7 is replaced, and the surface of the dust-proof glass 30 can be further kept clean.

  Further, even if the optical path of the image light is vertically below, the cleaning member 31 is not required to be disposed with respect to the dust-proof glass 30 as long as the toner fall by the shielding member 36 can be prevented only by the shielding member 36.

  Contrary to the above, the cleaning member 31 is fixedly arranged, and the dust-proof glass 30 is moved relative to the cleaning member 31 in conjunction with the separation / contact operation of the developing device by the separation means 90. It can also be configured to clean dirt. That is, the cleaning member 31 as the cleaning means or the dust-proof glass 30 as the transmission member moves relative to each other in conjunction with the operation of the separation means 90 to clean the dust-proof glass 30.

  It should be noted that the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.

Example 2
In the first embodiment, the cleaning member 31 is interlocked with the operation of the developing unit 40 along with the separation / contact operation of the developing unit 40 to clean the dustproof glass 30 and shield the optical path of the image light. As explained.

  In the second embodiment, an image forming apparatus that performs development separation / contact operation and cleaning of the dust-proof glass 30 and shielding of an optical path of image light at different timings will be described with reference to FIGS. More specifically, the transmission member 30 is cleaned before the developing roller 41 is separated from the photosensitive drum 1. Alternatively, after the developing roller 41 is separated from the photosensitive drum 1, the transmissive member 30 is cleaned. The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. Further, the overall configuration of the apparatus main body 100A and the contact / separation mechanism of the developing device are the same as those in the first embodiment, and thus description thereof is omitted.

  Also in the present embodiment, a cleaning shielding member 35 (35a, 35b, 35c, 35d) for cleaning and shielding the dustproof glass 30 along the optical case is provided on the scanner unit 3. The cleaning shielding member 35 also functions as a shielding plate that shields the dust-proof glass 30 when the cartridge 7 is replaced or when the developing device is apart from the developing device, and prevents dust, scattered / dropped toner from adhering to the dust-proof glass 30. it can.

  That is, the cleaning shielding member 35 as a shielding means is movable between a shielding position where the light irradiated from the scanner unit 3 passes toward the photosensitive drum, and an open position where the light path is opened. Yes, and moves in conjunction with the operation of the separating means. The cleaning shielding member 35 has a cleaning means for cleaning the dustproof glass 30, and the cleaning shielding member 35 or the dustproof glass 30 moves relative to each other in conjunction with the operation of the separation means to clean the dustproof glass 30. I do.

  Each cleaning shielding member 35 is attached to a long cleaning plate 36 (36a, 36b, 36c, 36d) disposed so as to cover the corresponding dustproof glass 30, and the dustproof glass 30 side of the cleaning plate 36. Brush 37 (37a, 37b, 37c, 37d). And it is urged | biased by the press spring (not shown) in the direction of dust-proof glass.

  The cleaning shielding member 35 is attached to the optical case in a movable state so as to slide in contact with the dustproof glass 30, and is between the shielding position A covering the dustproof glass 30 and the exposed position B exposing the dustproof glass 30. It is possible to move with. Further, sliding sliding with sliding cams 82 (82a, 82b, 82c, 82d) for moving the cleaning shielding member 35 provided coaxially with the separation cam 80 at both ends in the longitudinal direction of the cleaning shielding member 35. Portions 83 (83a, 83b, 83c, 83d) are provided.

  When the shielding cam 82 rotates together with the separation cam 80 and moves the cleaning shielding member 35 via the sliding portion 83, the cleaning shielding member 35 exposes the shielding position A covering the dustproof glass 30 and the dustproof glass 30. Move between position B.

  Further, as shown in the separation cam diagram of FIG. 11 and the relational diagram of the cleaning shielding member position, the shielding cam 82 and the separation cam 80 are set to have different profiles. Here, in FIG. 11, 1st to 4st are the first to fourth cartridges (7a, 7b, 7c, and 7d), respectively.

  Specifically, the cleaning shielding member 35 is set to move from the exposure position B to the shielding position A before the separation operation between the developing roller 41 and the photosensitive drum 1 is completed. That is, before the developing roller 41 is separated from the photosensitive drum 1, the cleaning shielding member 35 is selectively moved.

  Accordingly, it is possible to further prevent dirt from adhering to the dust-proof glass 30 due to toner scattering / dropping that occurs when the developing roller 41 and the photosensitive drum 1 are separated from each other, and image deterioration due to toner, dust, or the like attached to the dust-proof glass 30. Can be effectively prevented.

  Further, the profile of the separation cam 80 and the shielding cam 82 is devised and the cleaning member is moved after the developing roller 41 and the photosensitive drum 1 are separated, so that the dirt on the surface of the dust-proof glass 30 generated at the time of separation is immediately cleaned. can do.

  As described above, similarly to the first embodiment, it can be seen that the dust-proof glass 30 can be cleaned and shielded with a simple configuration by the developing separation operation in the image forming apparatus.

  Also in the present embodiment, the scope of the present invention is not limited only to them unless otherwise specified. For example, the brush 37 is used for cleaning the dustproof glass, but a pad member, a sponge member, or the like may be used.

  Contrary to the above, the dust-shielding glass 35 is fixedly disposed, and the dust-proof glass 30 is moved relative to the cleaning-shielding member 35 in conjunction with the separation / contact operation of the developing device by the separation means 90. It can also be configured to clean 30 dirt. The cleaning shielding member 35 or the dust-proof glass 30 moves relative to each other in conjunction with the operation of the separating means 90 to clean the dust-proof glass 30.

Example 3
In the first embodiment, the separation cam 80 that rotates in the separation / contact operation of the developing device is brought into direct contact with the separation boss 46 in the process cartridge 7 and moved left and right to thereby separate the developing device 4. The image forming apparatus performing the contact operation has been described. In the third embodiment, an image forming apparatus that performs a separation / contact operation using a rotating cam link mechanism for the development separation / contact operation will be described with reference to FIGS. 12 to 13.

  As shown in FIG. 12, the image forming apparatus 200 according to the present exemplary embodiment guides the cartridge 7 (7 a to 7 d) through the guide member 105 (105 a, 105 b, 105 c, 105 d), and follows the axial direction D of the drum 1. It is the composition which attaches. The separation means includes a cam and a link member that moves by the movement of the cam, and the link member moves the guide member. Other configurations are the same as those in the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. Further, the overall configuration of the apparatus main body 200A is the same as that of the first embodiment, and thus the description thereof is omitted.

  The link configuration of the present embodiment is shown in FIG. The rotation of the stepping motor 91 is transmitted to each clutch 110 (110a, 110b, 110c, 110d) via the gear 109 and the rod 108. When the clutch 110 is in the connected state, the rotation is transmitted from the clutch 110 to the rotating cam 101 (101a, 101b, 101c, 101d).

  When the clutch 110 is in a disconnected state, the rotation is not transmitted from the clutch 110 to the rotary cam 101. When the clutch 110 is in the connected state, the rotary cam 101 rotates and contacts one end of the first link member 102 (102a, 102b, 102c, 102d) having the center of rotation. The first link member 102 includes two second link members 103 (103a, 103b, 103c, 103d) having a rotation center at opposite ends with the rotation center therebetween, and a third link member 104 (104a, 104b). , 104c, 104d) are simultaneously engaged with one end.

  Furthermore, the guide member 105 (the opposite end portion is also a shielding means across the center of rotation of the end portion of the second link member 103 and the third link member 104 engaged with the first link member 102). 105a, 105b, 105c, 105d). Then, the two ribs 106 (106a, 106b, 106c, 106d) provided in the developing unit 40 of each cartridge are moved left and right through the respective guide members 105. Thereby, the developing unit 40 is moved to the separation position and the contact position.

  The separation position is a position where the developing roller 41 is separated from the photosensitive drum 1, and the contact position is a position where the developing roller 41 is in contact with the photosensitive drum 1. When the developing unit 40 is located at the separated position, the guide member 105 is located at a shielding position that shields the optical path of the image light output from the scanner unit 3. When the developing unit 40 is located at the contact position, the guide member 105 is located at an open position where the optical path of the image light output from the scanner unit 3 is opened.

In the present embodiment as well, as in the first embodiment, the following three states a to c can be selected according to the rotation angle of the rotating cam 101.

  State a: As shown in FIG. 13A and FIG. 14A, with respect to all the first to fourth cartridges 7, the maximum radius portion of the rotating cam 101 is opposed to one end portion of the first link member 102, The developing roller 41 is set in a standby state in which it is separated from the photosensitive drum 1.

  State b: As shown in FIG. 13B and FIG. 14B, with respect to all the first to fourth cartridges 7, the minimum radius portion of the rotating cam 101 is opposed to one end portion of the first link member 102, The developing roller 41 is brought into a full color state in contact with the photosensitive drum 1.

  State c: As shown in FIG. 13C, for the first to third cartridges 7a, 7b, and 7c of Y color, M color, and C color, the maximum radius portion of the rotary cam 101 is set to the first radius portion. The developing roller 41 is separated from the photosensitive drum 1 so as to face one end of the link member 102. For the fourth cartridge 7d of K color, the monolithic cartridge 1 in which the developing roller 41 is brought into contact with the photosensitive drum 1 with the minimum radius portion of the rotating cam 101 opposed to one end portion of the first link member 102. Set color.

  In the full color mode, development is performed in the order of the first cartridge 7a (Y color) → the second cartridge 7b (M color) → the third cartridge 7c (C color) → the fourth cartridge 7c (K color). The roller 41 comes into contact with the photosensitive drum 1 and the developing operation is executed.

  After the completion of the developing operation, the developing roller in the order of the first cartridge 7a (Y color) → second cartridge 7b (M color) → third cartridge 7c (C color) → fourth cartridge 7c (K color) 41 moves away from the photosensitive drum 1 to finish printing.

  That is, between the first to fourth cartridges 7a, 7b, 7c, 7d, the rotating cams 101a, 101b, 101c, The phase of 101d is shifted.

  Further, a developing clutch (not shown) serving as a drive switching means is provided in the driving means of the developing roller 40 so that the rotation / stop of the developing roller 41 can be switched when the photosensitive drum 1 is rotating.

  In this embodiment, for the first to third cartridges 7 a (Y), 7 b (M), and 7 c (C), one motor and each developing roller 41 are provided as photosensitive member driving means for driving each photosensitive drum 1. One motor is provided in the developing driving means for driving the motor. For the fourth cartridge 7d (K), one motor is used for the photosensitive member driving unit and the developing driving unit, and consideration is given to driving by a single motor in the mono-color mode.

  As a result, it is possible to drive the developing roller 41 only when developing a toner image on the photosensitive drum 1 and then contact the photosensitive drum 1, and the surface layer scraping / developing roller 41 of the photosensitive drum 1 can be driven. The deterioration of the is reduced.

  That is, when the cartridge 7 is attached / detached, the developing separation mechanism is in the state as shown in FIG. 13A and FIG. 14B, and the position where all the cartridges 7 are in the developing separation position. Therefore, the guide member 105 (105a, 105b, 105c, 105d) is in a state (shielded position) where the optical path of the exposure means is shielded. When the cartridge 7 is pulled out, it is possible to pull out the cartridge 7 while maintaining the developing separation state while guiding and regulating the rib 106 provided on the developing unit 40 with the rib on the dust-proof member 105.

  Further, when the cartridge 7 is inserted, the guide rib provided on the dust-proof member 105 is tapered in the insertion direction even when the cartridge 7 is inserted in the developing contact state, and the developing unit 40 of the cartridge 7 is tapered. Is guided to the development separation state. For this reason, when a cartridge is inserted into the apparatus, it is automatically placed in a development separated state.

  As described above, the shielding means also serves as a guide member for detachably attaching the cartridge 7 to the image forming apparatus main body 100A.

  Also in the third embodiment, the scope of the present invention is not limited only to them unless otherwise specified. For example, with respect to the link configuration, the contact position of the rotary cam and the link member may be reversed left and right, and three link arms may be arranged in series to perform a contact operation with the process cartridge at that node.

Example 4
In the third embodiment, the configuration in which the process cartridges 7 are mounted horizontally side by side has been described. In the present embodiment, a configuration in which the process cartridges 7 are mounted side by side at an angle θ with respect to the horizontal plane F will be described.

[Overall schematic configuration of image forming apparatus]
As shown in FIG. 15, the image forming apparatus 300 is a four-color full-color laser beam printer using an electrophotographic process, and forms a color image on a recording medium. The image forming apparatus 300 also includes a process cartridge detachment that uses the first to fourth process cartridges 7 (7a, 7b, 7c, and 7d) detachably attached to the image forming apparatus main body 300A. It is a method.

  Let E be a virtual plane that passes through each rotation center O of the drum 3 of each cartridge 7 when each cartridge 7 is mounted on the apparatus main body 300A. An inclination angle of the virtual plane E with respect to the horizontal plane F is defined as θ. In this embodiment, the inclination angle θ is set to approximately 20 °. In this way, the horizontal width of the apparatus main body 100A can be suppressed by arranging the plurality of cartridges 7 in the diagonal direction.

  Since the configuration of each cartridge 7 is the same as that of the third embodiment, it is omitted here.

  Also in this embodiment, exposure means 302 for each drum 1 is disposed below each cartridge 7.

  An intermediate transfer unit 5 is disposed above each cartridge 7. This unit 5 is a transfer means for primary transfer by superimposing a toner image formed on the drum 3 of each of the first to fourth cartridges 7 on an intermediate transfer belt (hereinafter referred to as a transfer belt) 11. The unit 11 has two parallel driving rollers 13 and a tension roller 14 arranged on the right side and the left side, and a flexible endless transfer belt 11 is wound around the rollers 13 and 14. Has been supported. The transfer belt 11 is disposed so as to be inclined with respect to the horizontal direction.

  The process cartridge 7 is guided to the guide member 105 (105a to 105d) from the axial direction of the drum 3 as in the third embodiment. Then, as shown in FIG. 16, the bearings (not shown) provided at both ends of the drum 3 in the axial direction come into contact with the positioning portions 301a to 301d of the apparatus main body 300A, whereby the process cartridge 7 is positioned.

  At that time, the process cartridge 7 is positioned by pressing the drum unit 50 by the support members 107 (107a to 107d). At that time, the ribs 106 (106 a to 106 d) provided in the developing unit 40 are in a state of being separated from the guide member 105. The guide member 105 is also a part of a separation mechanism that moves the developing unit 40 (40a to 40d) to a position where the drum 3 and the developing roller 41 (41a to 41d) are separated from each other as in the third embodiment.

  That is, as shown in FIG. 16, when the rib 106 and the guide member 105 are separated from each other, the developing unit 40 is connected to the drum 1 by a spring (not shown) provided between the developing unit 40 and the drum unit 50. The contact position where the developing roller 41 comes into contact is taken. When the guide member 105 moves in the arrow direction 312 (see FIG. 17), the rib 106 is pushed by the guide member 105, and the developing unit 40 rotates about the rotation center 49 (49a to 49d). The drum 3 and the developing roller 41 are moved away from each other. The separation mechanism for moving the guide member 105 is the same as that in the third embodiment, and is omitted here.

  In this embodiment, as shown in FIGS. 17 and 19, a sheet that is a cleaning member that cleans the glass 303 (303 a to 303 d) that is a transmission member through which light emitted from the exposure unit 302 is transmitted to the guide member 105. A member 305 (305a to 305d) is provided.

  The sheet member 305 is a flexible polyethylene terephthalate sheet. When the guide member 105 moves in the arrow direction 312, the deposit 311 attached to the glass 303 is moved to the storage portion 303 (303 a to 303 c) provided in the frame 303 of the exposure unit 302. In this embodiment, since the exposure means 302 is also provided obliquely with respect to the horizontal plane H, the deposit 311 can be efficiently stored in the storage portion 303 by moving the guide member 105 using gravity. .

  Here, the deposit 311 is toner dropped from the cartridge 7 or dust floating in the apparatus main body 300A, as described in the above-described embodiments. In addition, the guide member 105 is configured to open or block light emitted from the exposure unit 302. That is, when the guide member 105 is at the position shown in FIG. 17, the optical path L (La to Ld) is opened, and when the guide member 105 is at the position shown in FIG. 19, the optical path L is blocked. Take.

  That is, as in the third embodiment, when the cartridge 7 is attached or detached, the guide member 105 is in the position shown in FIGS. For this reason, when the cartridge 7 is pulled out, the rib 106 provided in the developing unit 40 is regulated by the guide member 105, so that the developing unit 40 can be pulled out while maintaining the separated position.

  Further, when the cartridge 7 is inserted, the guide rib provided on the guide member 105 is tapered in the insertion direction even when the developing unit 40 is inserted in the contact position state (see FIG. 14A), and the developing unit 40 is guided to the separated position. Therefore, when the cartridge 7 is inserted into the apparatus main body 300A, it is automatically placed in the development separation state and attached. Therefore, it is possible to prevent the toner from adhering to the glass 304 when the cartridge 7 is attached or detached.

  As described in the above embodiments, the separating means also serves as drive input means for separating and contacting the developing device (developer carrying member), and driving input means for the dustproof glass cleaning member and the shielding member. Accordingly, it is possible to provide an image forming apparatus that automatically improves optical characteristics in light beam scanning at a low cost without providing a new drive source. In addition, the dust-proof glass is cleaned in accordance with the separation and contact operation between the developing device and the image carrier, so that dust and toner stains generated during image formation can be efficiently cleaned.

  Further, along with the separation and contact operation between the developing device and the image carrier, the optical path through which the laser beam passes and the dustproof glass are shielded. As a result, it is possible to prevent dust and toner from being scattered or dropped when the image is formed, when the cartridge is attached or detached, or when the cartridge is impacted during the developing separation operation, and to adhere to dust-proof glass or other optical components.

  Further, by cleaning the dust-proof glass after completion of the separating operation between the developing device and the image carrier, it is possible to efficiently clean dirt such as toner scattering and dropping generated during the separating operation.

  Further, by shielding the dust-proof glass before the completion of the separating operation between the developing device and the image carrier, it is possible to prevent the dirt, such as toner scattering and dropping, generated during the separating operation from adhering to the dust-proof glass.

1 (1a, 1b, 1c, 1d) Photosensitive drum 2 (2a, 2b, 2c, 2d) Charging device 3 Scanner unit 4 (4a, 4b, 4c, 4d) Developing device 5 Intermediate transfer unit 6 (6a, 6b, 6c, 6d) Cleaning device 7 (7a, 7b, 7c, 7d) Process cartridge 11 Intermediate transfer belt (image carrier)
20 Fixing portion 30 (30a, 30b, 30c, 30d) Dust-proof glass 31 (31a, 31b, 31c, 31d) Cleaning member 35 (35a, 35b, 35c, 35d) Cleaning shielding member 40 (40a, 40b, 40c, 40d) Developing unit 41 (41a, 41b, 41c, 41d) Developing roller 46 (46a, 46b, 46c, 46d) Separating boss (receiving portion)
50 Photosensitive drum unit 54 Pressure spring 80 (80a, 80b, 80c, 80d) Separation cam 82 (82a, 82b, 82c, 82d) Shielding cam 91 Stepping motor 100 Image forming apparatus 101 (101a, 101b, 101c, 101d) Rotation Cam 102 (102a, 102b, 102c, 102d) Link A
103 (103a, 103b, 103c, 103d) Link B
104 (104a, 104b, 104c, 104d) Link C
105 (105a, 105b, 105c, 105d) Dust-proof member 106 (106a, 106b, 106c, 106d) Rib

Claims (9)

In an image forming apparatus comprising an apparatus main body and a process cartridge detachable from the apparatus main body,
The process cartridge is
A photosensitive drum unit having a photosensitive drum;
A developing unit having a developing roller for developing an electrostatic latent image formed on the photosensitive drum, the photosensitive member engages drum unit and binding, relative to the photosensitive drum, said developing roller to the photosensitive drum A developing unit capable of taking a contact position for contacting the developing roller and a separating position for separating the developing roller from the photosensitive drum;
Have
The apparatus main body is
Exposure means for irradiating the photosensitive drum with light to form an electrostatic latent image;
Separating means at a first position for disposing the developing unit at the contact position during image formation and at a second position for disposing the developing unit at the separation position during non-image formation;
A shielding member that is movable in conjunction with the operation of the separating means, wherein when the developing unit takes the contact position, an optical path through which the light passes is opened and the developing unit takes the separating position; A shielding member capable of shielding the optical path and receiving a developer;
When the process cartridge is mounted on the apparatus main body with the shielding member blocking the optical path , the developing unit is guided in conjunction with the mounting operation of the process cartridge while guiding the developing unit. A guide portion provided on the shielding member, which is moved from a position to the separated position;
Have
2. The image forming apparatus according to claim 1, wherein when the process cartridge is mounted, the separating unit is in the second position, and the shielding member is in a position shielding the optical path. Before SL shielding member image forming apparatus according to claim 1, characterized in that it has the guide portion. It said shielding member is image forming apparatus according to claim 1 or 2 characterized by having a cleaning member for cleaning the transparent member in which the light provided in the optical path passes through. The image forming apparatus according to claim 3 , wherein the cleaning member moves in conjunction with an operation of the separation unit before the developing unit moves to the separation position, and cleans the transmission member. . The image forming apparatus according to claim 3 , wherein the cleaning member moves in conjunction with an operation of the separation unit after the development unit has moved to the separation position, and cleans the transmission member. 6. The image forming apparatus according to claim 1, wherein the shielding member engages with the developing unit and moves as the developing unit moves. The image forming apparatus according to claim 1, wherein the shielding member is provided in the separation unit. Wherein the image forming apparatus, the photosensitive drum a color image forming apparatus having a plurality, that a plane passing through the center of the photosensitive drum in the inclined memorial respect to the horizontal plane, and each photosensitive drum is provided The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. 9. The process cartridge according to claim 1, wherein the process cartridge includes an elastic member that urges the developing unit in a direction in which the developing unit moves from the separated position to the contact position. Image forming apparatus.