JP3166408U - Image forming apparatus and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process cartridge capable of miniaturization, and an image forming apparatus capable of miniaturization by arranging a plurality of the process cartridges in parallel. SOLUTION: In a process casing 14 of a process cartridge 13, a charger 4 is arranged adjacent to a second wall 31, and in the process casing 14, a developing cartridge 17 is placed on a first wall 30 facing the second wall 31. It is mounted so as to protrude from the second opening 37 of the above. Therefore, in the process casing 14, the charger 4 and the second wall 31 can be brought closer to the first wall 30 by the amount that the developing cartridge 17 protrudes from the second opening 37 of the first wall 30. As a result, the process cartridge 13 can be miniaturized, and the printer 1 in which a plurality of process cartridges 13 are arranged in parallel in the front-rear direction in the main body casing 2 can be miniaturized. [Selection diagram] Fig. 2

Description

  The present invention relates to an electrophotographic image forming apparatus and a process cartridge equipped in the image forming apparatus.

  For example, in an electrophotographic image forming apparatus described in Patent Document 1 as an electrophotographic image forming apparatus, a plurality of process cartridges are arranged in parallel along a predetermined direction.

In each process cartridge, a photosensitive drum on which an electrostatic latent image is formed, a charger for charging the photosensitive drum, and a developing unit for developing the electrostatic latent image are housed in a cartridge frame.
2001-350307

  In the electrophotographic image forming apparatus described in Patent Document 1, since a plurality of process cartridges are arranged in parallel, the electrophotographic image forming apparatus has a certain size, but downsizing of the electrophotographic image forming apparatus is always desired. It is rare. For this purpose, it is inevitable to reduce the size of the process cartridge. However, for example, when the developing device is attached to or detached from the cartridge frame, the space for accommodating the developing device in the cartridge frame must be secured with some margin according to the shape of the developing device. It is difficult to reduce the size of the cartridge.

  An object of the present invention is to provide a process cartridge that can be reduced in size and an image forming apparatus that can be reduced in size by arranging a plurality of the process cartridges in parallel.

  In order to achieve the above object, the invention described in claim 1 is an image forming apparatus, wherein the image forming apparatus main body and a first process arranged in parallel along a predetermined direction in the image forming apparatus main body. A cartridge and a second process cartridge, wherein the first process cartridge and the second process cartridge are disposed opposite to the photosensitive drum on which the electrostatic latent image is formed, and the photosensitive drum A charging unit; a first wall having an opening; and a housing having a second wall facing the first wall and adjacent to the charging unit; and the second process cartridge includes: The current process unit is disposed opposite to the charger of the first process cartridge and is mounted on the housing so as to protrude from the opening of the second process cartridge. It is characterized in that it comprises a cartridge.

  A second aspect of the present invention is the first aspect of the present invention, wherein the developing cartridge has a first region for accommodating the developer and the developer, and the electrostatic latent image is visible. Forming a developer roller that forms a developer image by forming an image, a second region that accommodates a supply roller that supplies the developer to the developer roller, and a boundary between the first region and the second region; The second process cartridge is characterized in that the recess faces the charger of the first process cartridge through the opening.

  Further, the invention described in claim 3 is the invention described in claim 2, wherein a plurality of devices are provided corresponding to the plurality of process cartridges, extend substantially in parallel with the axial direction of the supply roller, and are arranged to face the photosensitive drum. And a transfer roller that transfers the developer image onto a transfer medium, and a cleaning that is supported by the housing, extends substantially parallel to the axial direction of the supply roller, and is disposed opposite the photosensitive drum to clean the photosensitive drum. The transfer roller corresponding to the first process cartridge, the cleaning roller of the first process cartridge, and the supply roller of the second process cartridge are in the axial direction of the supply roller It is characterized by being substantially arranged on the same straight line when projected from.

  According to a fourth aspect of the present invention, in the device according to the third aspect, the casing is provided with an exposure opening for exposing the photosensitive drum to the transfer roller side. A rib extending between the outlet and the outlet is provided.

  The invention described in claim 5 is characterized in that in the invention described in any one of claims 1 to 4, the process cartridge is detachable from the main body of the image forming apparatus.

  According to a sixth aspect of the present invention, there is provided a process cartridge, wherein a photosensitive drum on which an electrostatic latent image is formed, a charger that is disposed to face the photosensitive drum and charges the photosensitive drum, and an opening are formed. A housing having a first wall formed, a charger and a second wall facing the first wall, and a developing cartridge mounted on the housing so as to protrude from the opening. It is a feature.

  According to the first and sixth aspects of the present invention, in the case of the process cartridge housing, the charger is disposed adjacent to the second wall, and in the housing, the developing cartridge faces the second wall. It is mounted so as to protrude from the opening in the wall. Therefore, in the housing, the charger and the second wall can be brought closer to the first wall by the amount that the developing cartridge protrudes from the opening of the first wall.

  As a result, the process cartridge can be reduced in size. Further, it is possible to reduce the size of the image forming apparatus in which a plurality of process cartridges are arranged in parallel along a predetermined direction in the image forming apparatus main body.

  According to the second aspect of the present invention, the developing cartridge includes a first region that stores the developer, a second region that stores the developing roller and the supply roller, and a boundary between the first region and the second region. And a recess facing the opening is provided. In the second process cartridge, the concave portion faces the charger of the first process cartridge through the opening. The charger normally blows ion wind containing ions to the photosensitive drum to charge the surface of the photosensitive drum, and therefore it is necessary to supply air for that purpose to the charger. Here, since air is supplied from the space formed in the recess of the second process cartridge to the charger of the first process cartridge, the photosensitive drum of the first process cartridge can be charged efficiently. .

  According to the third aspect of the invention, the distance between the photosensitive drum of the first process cartridge and the photosensitive drum of the second process cartridge disposed adjacent to the first process cartridge can be minimized. The first process cartridge and the second process cartridge can be made more adjacent to each other. Accordingly, the plurality of process cartridges arranged in parallel can be reduced as a whole, and the image forming apparatus can be downsized.

  According to the invention described in claim 4, since the rib is provided between the exposure opening and the opening for exposing the photosensitive drum to the transfer roller side in the casing, the casing between the exposure opening and the opening is provided. The strength of the body can be secured.

  According to the fifth aspect of the invention, since the process cartridge is detachable from the main body of the image forming apparatus, the process cartridge can be maintained and the usability can be improved.

1 is a side sectional view showing an embodiment of a printer as an example of an image forming apparatus of the present invention. FIG. 2 is an enlarged view of two adjacent process cartridges extracted from FIG. 1. It is the perspective view which looked at four process cartridges arranged in parallel in a main part casing from the lower right side. FIG. 3 shows a state where the developing cartridge is removed. In FIG. 3, four developing cartridges are extracted and shown.

1. Printer FIG. 1 is a side sectional view showing an embodiment of a printer as an example of an image forming apparatus of the present invention. In addition, when referring to a direction, the illustrated direction arrow is referred to (the same applies to other drawings). Here, the left-right direction and the width direction are the same.

  The printer 1 is a color printer. As shown in FIG. 1, in the printer 1, four photosensitive drums 3 are arranged in parallel along the front-rear direction in a main body casing 2 as an example of an image forming apparatus main body. In the following, the four photosensitive drums 3 are divided into photosensitive drums 3K (black) and photosensitive drums 3Y (in accordance with the color (black, yellow, magenta or cyan) of a toner image (described later) formed on each photosensitive drum 3. Yellow), photosensitive drum 3M (magenta), and photosensitive drum 3C (cyan). For example, a scorotron charger 4, an LED unit 5, a developing roller 6, and a cleaning roller 18 are disposed opposite to each photosensitive drum 3.

  The surface of the photosensitive drum 3 is uniformly charged by the charger 4 and then exposed by an LED (not shown) provided in the LED unit 5. Thereby, an electrostatic latent image based on the image data is formed on the surface of each photosensitive drum 3. Each electrostatic latent image is visualized by toner (developer) carried on the developing roller 6 corresponding to each photosensitive drum 3, and a toner image (developer image) is formed on the surface of the photosensitive drum 3. The

  The paper P (transfer medium) is accommodated in a paper feed cassette 7 in the main casing 2. The paper P stored in the paper feed cassette 7 is transported to the transport belt 9 by changing the direction from the front side to the rear side by various rollers provided in the paper feed unit 8. The conveyor belt 9 is disposed opposite to the corresponding photosensitive drum 3 from below. The conveyor belt 9 is disposed between the photosensitive drums 3K, 3Y, 3M, and 3C and four transfer rollers 10 provided according to the four photosensitive drums 3. The toner image on the surface of each photosensitive drum 3 is transferred onto the paper P conveyed to the conveying belt 9 by the transfer bias applied to the transfer roller 10 and is sequentially superimposed.

  The sheet P on which the four color toner images are transferred is conveyed to the fixing unit 11. The toner image transferred onto the paper P is thermally fixed by the fixing unit 11. Thereafter, the paper P is discharged to the discharge tray 12 by changing the direction from the rear side to the front side by various rollers.

  Note that during such image formation, a cleaning bias for collecting toner is applied to the cleaning roller 18. As a result, the transfer residual toner remaining on the photosensitive drum 3 after the transfer of the toner image to the transport belt 9 (paper P) is once collected by the cleaning roller 18. At the end of image formation, a bias reverse to the cleaning bias is applied to the cleaning roller 18, so that the toner collected by the cleaning roller 18 is discharged from the cleaning roller 18 to the photosensitive drum 3. Later, it is collected by the developing roller 6. Thus, the photosensitive drum 3 is cleaned by the cleaning roller 18.

2. Process Cartridge FIG. 2 is an enlarged view of two adjacent process cartridges extracted from FIG. FIG. 3 is a perspective view of the four process cartridges arranged in parallel in the main body casing as viewed from the lower right side. FIG. 4 shows a state in which the developing cartridge is removed from FIG. 3 and 4 are slightly different in perspective directions.

  The printer 1 includes four process cartridges 13 corresponding to the respective colors. In the following, the four process cartridges 13 are distinguished from the process cartridge 13K (black), the process cartridge 13Y (yellow), the process cartridge 13M (magenta), and the process cartridge 13C (cyan) corresponding to each color.

  These process cartridges 13 are arranged in parallel in the main casing 2 along the front-rear direction. Specifically, these process cartridges 13 are arranged in the order of the process cartridge 13K, the process cartridge 13Y, the process cartridge 13M, and the process cartridge 13C from the front side.

  The process cartridge 13 is detachable from the main casing 2. Specifically, when the process cartridge 13 is detached, the inside of the main casing 2 is opened upward by shifting the discharge tray 12 positioned above the process cartridge 13, and the process cartridge 13 is raised from the main casing 2. . On the other hand, when the process cartridge 13 is mounted, the inside of the main body casing 2 is opened upward by shifting the discharge tray 12, and the process cartridge 13 is lowered into the main body casing 2. The four process cartridges 13 may be attached and detached integrally, or each process cartridge 13 may be attached and detached individually.

  As shown in FIG. 2, the process cartridge 13 includes a process casing 14 as an example of a housing. The process casing 14 has a box shape elongated in the width direction. In a state where the process cartridge 13 is mounted on the main casing 2, the process casing 14 is inclined obliquely forward and upward (see also FIG. 1).

  The process casing 14 integrally includes a first wall 30, a second wall 31, a third wall 32, a fourth wall 33, a fifth wall 34, and a sixth wall 35 (the fifth wall 34 and the sixth wall 35). (See FIG. 3 and FIG. 4 for 35). The first wall 30, the second wall 31, the third wall 32, the fourth wall 33, the fifth wall 34 and the sixth wall 35 form an outer shell of the process casing 14.

  The first wall 30 has a plate shape that is long in the width direction, and is inclined obliquely upward to the front side.

  The second wall 31 has a plate shape that is long in the width direction, and is inclined obliquely upward to the front side. The second wall 31 faces the first wall 30 (specifically, the lower portion of the first wall 30) with a space therebetween, and extends in parallel with the first wall 30.

  The third wall 32 has a plate shape that is long in the width direction, and extends substantially horizontally from the lower end of the first wall 30 to the rear side. The rear end of the third wall 32 is slightly bent toward the upper rear side and is continuous with the lower end of the second wall 31.

  The fourth wall 33 has a plate shape that is long in the width direction, and extends substantially vertically upward from the upper end of the first wall 30.

  As shown in FIG. 3, the fifth wall 34 has a plate shape that is substantially rectangular when viewed in the width direction. The fifth wall 34 is connected to each right edge of the first wall 30, the second wall 31, the third wall 32, and the fourth wall 33. A guide groove 46 is formed on the left side surface of the fifth wall 34. The guide groove 46 extends downward while being slightly curved from a substantially central portion in the vertical direction of the rear upper edge of the fifth wall 34. A lower end portion (referred to as an end point 47) of the guide groove 46 is an opening that penetrates the fifth wall 34 and is exposed to the right side from the fifth wall 34.

  The sixth wall 35 has substantially the same shape as the fifth wall 34 and is connected to the left end edges of the first wall 30, the second wall 31, the third wall 32, and the fourth wall 33. Similarly to the fifth wall 34, a guide groove 46 is also formed on the right side surface of the sixth wall 34 (see FIG. 4).

  As shown in FIG. 4, the process casing 14 includes a first opening 36, a second opening 37 as an example of an opening, and a third opening 38 as an example of an exposure opening.

  The first opening 36 is a substantially rectangular opening, and is defined by upper end edges of the second wall 31, the fourth wall 33, the fifth wall 34, and the sixth wall 35 in the process casing 14 (FIG. 2). See also).

  The second opening 37 is a substantially rectangular opening and is formed over substantially the entire lower region of the first wall 30.

  The third opening 38 is a substantially rectangular opening and is formed over substantially the entire front region of the third wall 32.

  Here, a portion of the first wall 30 below the second opening 37 and a portion of the third wall 32 on the front side of the third opening 38 are referred to as ribs 39. The rib 39 extends in the width direction between the second opening 37 and the third opening 38, and is spanned between the fifth wall 34 and the sixth wall 35.

  As shown in FIG. 2, the process casing 14 includes a corresponding photosensitive drum 3, a charger 4, a developing roller 6, a supply roller 15, a toner hopper 16 that contains toner, a cleaning roller 18, and the like. Is mainly arranged. The central axes (rotating shafts) of the photosensitive drum 3, the developing roller 6, the supply roller 15, and the cleaning roller 18 extend along the width direction. In the process cartridge 13, the toner stored in the toner hopper 16 is supplied to the developing roller 6 by the supply roller 15 and is carried on the developing roller 6 as described above.

  The developing roller 6, the supply roller 15, and the toner hopper 16 are unitized, and can be detachably attached to the process casing 14 as a developing cartridge 17. The developing cartridge 17 is attached to and detached from the main casing 2 while being attached to the process casing 14 (that is, as a part of the process cartridge 13). Further, only the developing cartridge 17 can be attached to and detached from the main casing 2 while the process casing 14 is still attached to the main casing 2. The developing cartridge 17 will be described in detail later.

  Regarding the photosensitive drum 3, the process casing 14 is provided with a drum shaft 40. The drum shaft 40 extends along the width direction. The right end of the drum shaft 40 is supported by the lower portion of the fifth wall 34, and the left end of the drum shaft 40 is supported by the lower portion of the sixth wall 35 (see FIGS. 3 and 4). A drum shaft 40 is inserted into a circular center portion of the photosensitive drum 3, and the photosensitive drum 3 is disposed in the process casing 14 (specifically, the second wall 31, the third wall 32, the fifth wall 34, and the sixth wall 35. In the space surrounded by) is supported by the process casing 14 via the drum shaft 40 and is rotatable about the drum shaft 40. A lower portion of the surface (outer peripheral surface) of the photosensitive drum 3 is exposed to the lower side (transfer roller 10 side) from the third opening 38 (see FIG. 4).

  The charger 4 is sandwiched from the width direction by a fifth wall 34 and a sixth wall 35 (see FIG. 3) so as to be adjacent to the second wall 31 on the upper oblique rear side of the photosensitive drum 3. The photosensitive drum 3 is opposed to the photosensitive drum 3 with an interval so as not to come into contact with the photosensitive drum 3. Specifically, the charger 4 is provided between the discharge wire 41 and the photosensitive drum 3, and is disposed between the discharge wire 41 and the photosensitive drum 3. The charge amount from the discharge wire 41 to the photosensitive drum 3 is provided. And a grid 42 for controlling. At the same time as applying a bias voltage to the grid 42, a high voltage is applied to the discharge wire 41 to corona discharge the discharge wire 41, thereby uniformly charging the surface of the photosensitive drum 3. The charger 4 is provided with a wire cleaner (not shown) that sandwiches the discharge wire 41, and the wire cleaner cleans the discharge wire 41 by sliding in the width direction. Here, a fourth opening 43 is formed in the second wall 31. The fourth opening 43 is an opening that is long in the width direction, and the charger 4 (particularly, the discharge wire 41) is exposed to the upper rear side through the fourth opening 43.

  The cleaning roller 18 is disposed to face the photosensitive drum 3 from the rear side so as to contact the surface of the photosensitive drum 3. In the cleaning roller 18, the right end portion is rotatably supported by the fifth wall 34 and the left end portion is rotatably supported by the sixth wall 35.

  The internal space of the process casing 14 is partitioned into a first space 44 in which the photosensitive drum 3, the charger 4 and the cleaning roller 18 are disposed, and a second space 45. The second space 45 is continuous from the first space 44 and is located above the first space 44 diagonally forward. The second space 45 communicates with the first opening 36 on the rear upper side and communicates with the second opening 37 on the lower front side. The developing cartridge 17 is disposed in the second space 45. Further, at the boundary portion between the first space 44 and the second space 45 (specifically, the portion corresponding to the periphery of the lower end of the first opening 36), the lower end portion of the LED unit 5 (light is emitted to expose the photosensitive drum 3). Part to be arranged) is arranged.

  When the four process cartridges 13 are arranged in parallel along the front-rear direction in the main casing 2 (see FIG. 1), as shown in FIGS. 2 to 4, the second process cartridge 13 (process as an example) The first wall 30 of the cartridge 13 </ b> Y) is slightly spaced from the second wall 31 of the first process cartridge 13 (for example, the process cartridge 13 </ b> K) disposed adjacent to the front side of the second process cartridge 13. Are facing each other. In this state, as shown in FIG. 2, the second opening 37 of the first wall 30 of the second process cartridge 13 faces the fourth opening 43 of the second wall 31 of the first process cartridge 13. .

  In other words, as shown in FIG. 1, the second opening 37 of the process cartridge 13C faces the fourth opening 43 of the process cartridge 13M. Similarly, the second opening 37 of the process cartridge 13M faces the fourth opening 43 of the process cartridge 13Y. The second opening 37 of the process cartridge 13Y faces the fourth opening 43 of the process cartridge 13K.

  Here, the four transfer rollers 10 described above extend substantially parallel to the axial direction (width direction) of the supply roller 15. The cleaning roller 18 also extends substantially parallel to the axial direction of the supply roller 15. As shown in FIG. 2, the transfer roller 10 (specifically, the central axis of the transfer roller 10) corresponding to (opposed to) the photosensitive drum 3 of the first process cartridge 13 and the cleaning roller 18 of the first process cartridge 13. (Specifically, the central axis of the cleaning roller 18) and the supply roller 15 (specifically, the central axis of the supply roller 15) of the second process cartridge 13 disposed adjacent to the rear side of the first process cartridge 13 When projected from the width direction, they are substantially arranged on the same straight line X.

  That is, as shown in FIG. 1, the central axis of the transfer roller 10 facing the photosensitive drum 3K of the process cartridge 13K, the central axis of the cleaning roller 18 of the process cartridge 13K, and the central axis of the supply roller 15 of the process cartridge 13Y Are substantially arranged on the same straight line X when projected from the width direction. Similarly, the central axis of the transfer roller 10 facing the photosensitive drum 3Y of the process cartridge 13Y, the central axis of the cleaning roller 18 of the process cartridge 13Y, and the central axis of the supply roller 15 of the process cartridge 13M are projected from the width direction. When arranged, they are almost arranged on the same straight line X. Then, the central axis of the transfer roller 10 facing the photosensitive drum 3M of the process cartridge 13M, the central axis of the cleaning roller 18 of the process cartridge 13M, and the central axis of the supply roller 15 of the process cartridge 13C are projected from the width direction. Sometimes, they are almost arranged on the same straight line X.

3. Developing Cartridge FIG. 5 shows four developing cartridges extracted from FIG. 3 and 5 are slightly different in perspective directions.

  As shown in FIG. 2, the developing cartridge 17 includes a developing casing 50. The developing casing 50 has a box shape elongated in the width direction (see FIG. 5), and has a size that can be accommodated in the second space 45 of the process casing 14.

  In a state where the process cartridge 13 is mounted on the main body casing 2 and the developing cartridge 17 is mounted on the process casing 14 (see FIG. 1), the developing casing 50 is inclined obliquely upward to the front side, like the process casing 14. . Here, in the developing casing 50, a side wall facing the first wall 30 of the process casing 14 is referred to as a developing side wall 48. A lower opening 49 is formed in the lower part of the developing casing 50, and the lower opening 49 communicates with the inside of the developing casing 50.

  A partition wall 51 extending in the width direction is provided in the middle of the developing casing 50 in the vertical direction. The developing casing 50 is partitioned into a first area 52 and a second area 53 by the partition wall 51. The first area 52 is above the second area 53. A communication hole 54 is formed in the partition wall 51, and the first region 52 and the second region 53 communicate with each other through the communication hole 54.

  The first area 52 corresponds to the inside of the toner hopper 16 and contains toner. An agitator 55 is disposed in the first region 52. The agitator 55 includes a shaft 56 extending along the width direction, and a blade 57 attached to the shaft 56. In the agitator 55, when the blade 57 rotates around the shaft 56, the toner in the first region 52 is stirred by the blade 57 and discharged from the communication hole 54 to the second region 53. Here, the first region 52 is partitioned into a substantially circular shape when viewed in the width direction so as to allow rotation of the blades 57. A portion corresponding to the first region 52 in the developing side wall 48 is formed in an arc shape that bulges obliquely forward and downward as viewed in the width direction in accordance with the shape of the first region 52. 58.

  The second region 53 accommodates the developing roller 6 and the supply roller 15. The supply roller 15 is adjacently disposed below the communication hole 54. The developing roller 6 is disposed on the rear side of the supply roller 15 (specifically, obliquely on the lower rear side). In the developing roller 6, the outer peripheral surface on the upper front side is in pressure contact with the outer peripheral surface of the supply roller 15, and a nip is formed between the developing roller 6 and the supply roller 15. In the developing roller 6, the rear outer peripheral surface is exposed from the lower opening 49 of the developing casing 50. Further, the right end of the developing roller 6 (specifically, the shaft of the developing roller 6) is exposed on the right side wall of the developing casing 50 (see FIG. 5). Although not shown, the left end of the developing roller 6 (specifically, the shaft of the developing roller 6) is exposed on the left side wall of the developing casing 50. A base end portion of the layer thickness regulating blade 66 is attached to the upper end edge of the lower opening 49 in the developing casing 50. A pressure contact rubber is provided at the free end of the layer thickness regulating blade 66, and the pressure contact rubber presses the surface of the developing roller 6.

  In a state where the developing cartridge 17 is mounted on the process casing 14, a portion of the developing roller 6 exposed from the lower opening 49 of the developing casing 50 is in contact with the photosensitive drum 3. The toner discharged from the communication hole 54 to the second region 53 is supplied from the supply roller 15 to the developing roller 6 through the nip described above. The toner supplied to the developing roller 6 becomes a thin layer with a certain thickness by entering between the pressure contact rubber of the layer thickness regulating blade 66 and the surface of the developing roller 6, and is carried on the surface of the developing roller 6. As described above, the toner carried on the developing roller 6 makes the electrostatic latent image on the photosensitive drum 3 visible.

  Here, a portion corresponding to the supply roller 15 in the developing side wall 48 is formed in an arc shape that bulges substantially forward as viewed in the width direction according to the shape of the supply roller 15. Is done. The second arc portion 59 is continuous downward with respect to the first arc portion 58, and the developing side wall 48 is slanted as an example of a recess at the boundary between the first arc portion 58 and the second arc portion 59. A first recess 60 that is recessed in a substantially V shape on the rear upper side is formed. The base end portion of the partition wall 51 is located at the deepest portion of the first recess 60. Therefore, the first recess 60 forms a boundary between the first region 52 and the second region 53.

  As shown in FIG. 5, the first recess 60 is formed over the entire region in the width direction of the developing side wall 48. A plurality of first ribs 61 are provided in the first recess 60 at intervals in the width direction. The first rib 61 is a substantially triangular thin plate having a size capable of closing the first recess 60 when viewed from the width direction, and connects the first arc portion 58 and the second arc portion 59. Thereby, the strength of the developing side wall 48 in the first recess 60 is ensured.

  Further, as shown in FIG. 2, the lower portion of the developing side wall 48 from the second arc portion 59 (the lower end of the lower opening 49 and the portion corresponding to the developing roller 6) has a substantially trapezoidal shape at the upper rear side. A recessed second recess 62 is formed. The second recess 62 is shallower than the first recess 60. As shown in FIG. 5, the second recess 62 is formed over the entire area of the developing side wall 48 in the width direction. A plurality of second ribs 63 are provided in the second recess 62 at intervals in the width direction. The second rib 63 has a substantially trapezoidal thin plate shape having a size capable of closing the second recess 62 when viewed in the width direction. The second rib 63 and the development side wall 48 are provided below the second arc portion 59. Connecting the parts. Thereby, the strength of the developing side wall 48 in the second recess 62 is ensured. The second recess 62 is provided with a third rib 65. The third rib 65 extends along the width direction and partitions the third recess 62 in the vertical direction.

4). Mounting of Developer Cartridge to Process Casing When mounting the developer cartridge 17 to the process casing 14, first, the process car is placed on a horizontal surface so that the first opening 36 (see FIG. 2) faces upward and is in a horizontal state. The developing cartridge 17 is lowered with respect to the sing 14 from above and is pushed into the second space 45 from the first opening 36 of the process casing 14 (see FIGS. 2 and 4). At this time, the right end portion of the developing roller 6 is received in the guide groove 46 (see FIG. 4) of the fifth wall 34 of the process casing 14 and advances in the guide groove 46. Similarly, the left end portion of the developing roller 6 is received in the guide groove 46 (see FIG. 4) of the sixth wall 35 of the process casing 14 and advances in the guide groove 46. Thereafter, as shown in FIG. 3, when the developing cartridge 17 is pushed into the second space 45 until the right end portion and the left end portion of the developing roller 6 reach the end point 47 of the corresponding guide groove 46, the developing cartridge 17 is moved to the second space 45. The housing 45 is accommodated, and the mounting of the developing cartridge 17 to the process casing 14 is completed.

  In this state, as shown in FIG. 2, the portion of the developing roller 6 exposed from the lower opening 49 contacts the photosensitive drum 3 as described above and protrudes from the developing side wall 48 (specifically, from the first arc portion 58). The rib (not shown) is in contact with the first wall 30 of the process casing 14 (specifically, a roller (not shown) provided on the first wall 30). Thereby, the developing cartridge 17 is positioned in the process casing 14 (specifically, the second space 45). In each process cartridge 13 in which the mounting of the developing cartridge 17 to the process casing 14 is completed, the second arc portion 59, the first concave portion 60, the first rib 61, the second concave portion 62, and the second rib 63 are provided on the developing side wall 48. However, it faces the second opening 37 of the first wall 30 and is exposed from the second opening 37 to the outside (in the obliquely lower front side in FIG. 2) (see also FIG. 3). In particular, with reference to the state of FIG. 2, the second arc portion 59 protrudes obliquely forward and downward from the second opening 37. Here, the fact that the second arc portion 59 protrudes from the second opening 37 is the inner surface 64 of the first wall 30 in the second opening 37 (the surface facing the process casing 14 in the first wall 30), It means that the second arc portion 59 protrudes to the outside of the process casing 14 (downwardly obliquely downward) from the illustrated portion. In each of the process cartridge 13K, the process cartridge 13Y, the process cartridge 13M, and the process cartridge 13C (see FIGS. 1 and 3), the second arc portion 59 protrudes from the second opening 37 to the outside of the process casing 14.

  As described above, the developing cartridge 17 mounted on the process casing 14 is disposed (mounted) in the second space 45 of the process casing 14 so as to protrude from the second opening 37 at the second arc portion 59.

  When all (four) developing cartridges 17 are attached to the corresponding process casings 14, these developing cartridges 17 are arranged along the front-rear direction in the main body casing 2 in the same manner as the four process cartridges 13. They are arranged in parallel (see also FIGS. 1, 3 and 5).

  In this state, as described above, the second opening 37 of the first wall 30 of the second process cartridge 13 is adjacent to the second process cartridge 13 on the front side. The second wall 31 faces the fourth opening 43. In each process cartridge 13 (second process cartridge 13), as described above, the first recess 60 and the second recess 62 of the second process cartridge 13 form the first wall 30 of the second process cartridge 13. The second opening 37 is exposed and is exposed obliquely forward and downward from the second opening 37. Here, the first recess 60 (developing cartridge 17) exposed from the second opening 37 in the second process cartridge 13 passes through the second opening 37 and the fourth opening 43 in the first process cartridge 13. Opposite to the charger 4 exposed obliquely to the upper rear side.

  That is, as shown in FIG. 1, the first recess 60 of the process cartridge 13Y faces the charger 4 of the process cartridge 13K. Similarly, the first recess 60 of the process cartridge 13M faces the charger 4 of the process cartridge 13Y. The first recess 60 of the process cartridge 13C faces the charger 4 of the process cartridge 13M.

  As shown in FIG. 2, the second recess 62 exposed from the second opening 37 in the second process cartridge 13 does not face the charger 4 of the first process cartridge 13. Is placed close to.

5. Operational Effect (1) As described above, in the process casing 14 of the process cartridge 13, the charger 4 is disposed adjacent to the second wall 31, and the developing cartridge 17 is disposed on the second wall 31 in the process casing 14. It mounts | wears so that it may protrude from the 2nd opening 37 of the 1st wall 30 which opposes. Therefore, in the process casing 14, the charger 4 and the second wall 31 can be brought closer to the first wall 30 by the amount that the developing cartridge 17 protrudes from the second opening 37 of the first wall 30.

  As a result, the process cartridge 13 can be reduced in size. Further, it is possible to reduce the size of the printer 1 (see FIG. 1) in which a plurality of process cartridges 13 are arranged in parallel in the main body casing 2 along the front-rear direction. Note that at least one process cartridge 13 only needs to be arranged so that the developing cartridge 17 protrudes from the second opening 37, but in all the process cartridges 13, the developing cartridge 17 is arranged to protrude from the second opening 37. If so, the printer 1 can be significantly reduced in size.

  (2) The developing cartridge 17 forms a boundary between the first region 52 for storing the toner, the second region 53 for storing the developing roller 6 and the supply roller 15, and the first region 52 and the second region 53. A first recess 60 facing the second opening 37 is provided. In the second process cartridge 13, the first recess 60 opposes the charger 4 of the first process cartridge 13 disposed adjacent to the front side of the second process cartridge 13 through the second opening 37. . The charger 4 normally charges the surface of the photosensitive drum 3 by blowing an ion wind containing ions to the photosensitive drum 3, and therefore it is necessary to supply air for that purpose to the charger 4. Here, since air is supplied from the space formed in the first recess 60 of the second process cartridge 13 to the charger 4 of the first process cartridge 13, the first process cartridge 13 is efficiently exposed. The drum 3 can be charged.

  As described above, the second recess 62 exposed from the second opening 37 in the second process cartridge 13 does not face the charger 4 of the first process cartridge 13, but is close to the charger 4. Be placed. Therefore, air can also be supplied to the charger 4 of the first process cartridge 13 from the space formed in the second recess 62 of the second process cartridge 13, and the first process cartridge 13 can be more efficiently supplied. The photosensitive drum 3 can be charged.

  In addition, a sufficient space for taking air into the charger 4 is secured behind the charger 4 of the process cartridge 13C (see FIG. 1) located at the end.

  (3) In the printer 1, the transfer roller 10 corresponding to the first process cartridge 13, the cleaning roller 18 of the first process cartridge 13, and the first process cartridge 13 are disposed adjacent to the rear side. The supply roller 15 of the second process cartridge 13 is substantially arranged on the same straight line X when projected from the width direction (see also FIG. 1).

  Thus, the interval between the photosensitive drum 3 of the first process cartridge 13 and the photosensitive drum 3 of the second process cartridge 13 disposed adjacent to the rear side of the first process cartridge 13 can be minimized. Therefore, the first process cartridge 13 and the second process cartridge 13 can be made more adjacent to each other. Accordingly, the plurality of process cartridges 13 arranged in parallel can be reduced as a whole, and the printer 1 can be downsized.

  (4) In the process casing 14, since the rib 39 is provided between the third opening 38 and the second opening 37 for exposing the photosensitive drum 3 to the transfer roller 10 side, the third opening 38 and the second opening are provided. The strength of the process casing 14 with respect to 37 can be ensured (see FIG. 4).

  (5) Since the process cartridge 13 is detachable from the main casing 2, the process cartridge 13 can be maintained, and the usability can be improved.

6). Modified Example In the above-described embodiment, a so-called direct transfer type color printer in which the toner image on the surface of each photosensitive drum 3 is directly transferred to the paper P has been exemplified. The present invention can also be applied to an intermediate transfer type color printer or monochrome printer in which a toner image is once transferred to an intermediate transfer member and then transferred to a sheet P at a time.

  Further, although the photosensitive drum 3 is exposed by the LED, the present invention can be applied to a laser printer that exposes the photosensitive drum 3 by a laser.

DESCRIPTION OF SYMBOLS 1 Printer 2 Main body casing 3 Photosensitive drum 4 Charger 6 Developing roller 10 Transfer roller 13 Process cartridge 14 Process casing 15 Supply roller 17 Developing cartridge 18 Cleaning roller 30 1st wall 31 2nd wall 37 2nd opening 38 3rd opening 39 Rib 52 1st area | region 53 2nd area | region 60 1st recessed part X Straight line

Claims (6)

An image forming apparatus main body;
A first process cartridge and a second process cartridge arranged in parallel in a predetermined direction in the image forming apparatus main body;
The first process cartridge and the second process cartridge are:
A photosensitive drum on which an electrostatic latent image is formed;
A charger disposed opposite to the photosensitive drum for charging the photosensitive drum;
A housing having a first wall in which an opening is formed, and a second wall facing the first wall and adjacent to the charger;
The second process cartridge is
An image forming apparatus comprising: a developing cartridge that is disposed opposite to the charger of the first process cartridge and is mounted on the casing so as to protrude from the opening of the second process cartridge. . In the developing cartridge,
A first region containing a developer;
A second region containing a developing roller that carries the developer and visualizes the electrostatic latent image to form a developer image; and a supply roller that supplies the developer to the developing roller;
Forming a boundary between the first region and the second region, a recess facing the opening is provided;
2. The image forming apparatus according to claim 1, wherein in the second process cartridge, the concave portion faces the charger of the first process cartridge through the opening. A plurality of transfer rollers provided in accordance with the plurality of process cartridges, extending substantially parallel to the axial direction of the supply roller, disposed opposite to the photosensitive drum, and transferring the developer image onto a transfer medium;
A cleaning roller supported by the housing, extending substantially parallel to the axial direction of the supply roller, and disposed opposite to the photosensitive drum to clean the photosensitive drum;
When the transfer roller corresponding to the first process cartridge, the cleaning roller of the first process cartridge, and the supply roller of the second process cartridge are projected from the axial direction of the supply roller The image forming apparatus according to claim 2, wherein the image forming apparatus is substantially arranged on the same straight line.   The said housing | casing is formed with the exposure opening for exposing the said photosensitive drum to the said transfer roller side, The rib extended between the said opening and the said exposure opening is provided, It is characterized by the above-mentioned. The image forming apparatus according to 3.   The image forming apparatus according to claim 1, wherein the process cartridge is detachable from the main body of the image forming apparatus. A photosensitive drum on which an electrostatic latent image is formed;
A charger disposed opposite to the photosensitive drum for charging the photosensitive drum;
A housing having a first wall in which an opening is formed, and a second wall facing the charger and the first wall;
A process cartridge comprising: a developing cartridge mounted on the housing so as to protrude from the opening.

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