JP4423567B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a color laser printer.

As an electrophotographic color laser printer, a so-called tandem color printer is provided with a plurality of process units each including a developer hopper, a developing roller, and a photosensitive drum corresponding to toner of each color of yellow, magenta, cyan, and black. Laser printers are known.
In such a tandem color laser printer, in each process unit, the toner of each color stored in the developer hopper is supplied to the photosensitive drum by the developing roller, and the toner image of each color is formed on the photosensitive drum almost simultaneously. Therefore, a color image can be formed at almost the same speed as that of a monochrome laser printer.

In such a tandem type color laser printer, for example, as described in Japanese Patent Laid-Open No. 9-274423 (Patent Document 1), in each process unit, a photosensitive belt transports a sheet of paper on a photosensitive drum. In order to form an electrostatic latent image on the photosensitive drum, the developing roller is arranged on the side of the photosensitive drum. There is known a recording head for exposing a photosensitive drum.
JP-A-9-274423

  However, in the device described in Patent Document 1, it is necessary to dispose the recording head near the photosensitive drum in order to prevent exposure failure of the recording head to the photosensitive drum. For this reason, as described above, the recording head is disposed on the opposite side of the photosensitive drum from the position facing the conveying belt. However, in such an arrangement, the recording head interferes when an attempt is made to replace the photosensitive drum. In addition, the recording head is fixed to the upper lid and is provided to move as the upper lid is opened and closed.

However, if the recording head moves each time the upper lid is opened and closed, the relative position of the recording head with respect to the photosensitive drum may vary, which may cause an image shift.
SUMMARY OF THE INVENTION An object of the present invention is to provide a tandem type image forming apparatus capable of smoothly attaching and detaching a process unit while ensuring accurate exposure to an image carrier.

In order to achieve the above object, an invention according to claim 1 is an image forming apparatus comprising a developer accommodating chamber for accommodating a developer, a developer bearing member for bearing the developer, and the developer bearing member. A process unit detachably attached to the main body of the image forming apparatus, and a main body of the image forming apparatus. An exposure unit that is fixed to the image carrier and scans the image carrier with laser light to form an electrostatic latent image on the image carrier for each color of a plurality of developers, and the process unit The exposure unit is alternately arranged, and includes an opening / closing member that opens and closes with respect to the image forming apparatus main body on the opposite side of the transfer position to which the developer image carried on the image carrier is transferred. , The process unit Is provided so as to be attached to and detached from the image forming apparatus main body through an opening formed by opening the opening and closing member, and the image carrier and the developer carrying are removed from the image forming apparatus main body. The image forming member and the developer carrying member are arranged in a vertically arranged state in the vertical direction and in a horizontally placed state in which the image carrying member and the developer carrying member are arranged in the horizontal direction. A first abutting portion that abuts on the placement surface in the vertically placed state, and a second abutment portion that abuts on the placement surface in the laterally placed state, and the process unit includes: A developing unit having a developer accommodating chamber and the developer carrying member; and an image carrying unit having the image carrying member. The developing unit and the image carrying unit are integrated with the image forming apparatus main body. Removable and present The first abutting portion is provided on the image carrying portion, and the second abutting portion is provided between the image carrying portion and the developing portion. It is characterized by being provided in each .

According to such a configuration, since the process unit is arranged alternately with the exposure unit, the transfer position to which the developer image carried on the image carrier in the image carrier is transferred without moving the exposure unit. On the opposite side, the opening / closing member can be attached to and detached from the image forming apparatus main body through an opening formed by opening. Therefore, the exposure means is fixed to the image forming apparatus main body without being moved when the process unit is attached or detached, so that accurate exposure can be secured, and the process unit is fixed to the image forming apparatus main body. It can be smoothly attached to and detached from the image forming apparatus main body without interfering with the exposed exposure means. In addition, the process unit can be stably mounted in the vertically or horizontally placed state by the first contact portion and the second contact portion in a state where the process unit is detached from the image forming apparatus main body. Can be placed. Therefore, it is possible to prevent the process unit from overturning and to facilitate handling in either the vertically placed state or the horizontally placed state.
Further, according to such a configuration, since the developing unit can be attached to and detached from the image carrying unit, when the developer is empty, the used developing unit is detached from the image carrying unit, and then the image is obtained. If a new developing unit is mounted on the carrying unit, it is possible to replace only the developing unit without replacing an image carrying unit that is less frequently replaced. As a result, it is possible to reduce running costs and industrial waste. On the other hand, when replacing the image bearing member, the developing unit and the image bearing unit are detached from the main body of the image forming apparatus, and the developing unit is detached from the used image bearing unit. If the developing unit is attached to the carrying unit, and these are integrally attached to the image forming apparatus main body, the image carrying unit having a low replacement frequency can be easily replaced.

According to a second aspect of the present invention, there is provided an image forming apparatus comprising: a developer storage chamber that stores a developer; a developer carrier that carries the developer; and a developer that is carried on the developer carrier. An image carrier that carries a developer image formed by developing an electrostatic latent image, a process unit that is detachable from the image forming apparatus main body, and is fixed to the image forming apparatus main body, An exposure unit for forming an electrostatic latent image on the image carrier for each color of a plurality of developers, and a transfer position of the image carrier on which the developer image carried on the image carrier is transferred; On the opposite side, an opening / closing member that opens and closes with respect to the image forming apparatus main body is provided, and the process unit is provided to be attached to and detached from the image forming apparatus main body through an opening formed by opening the opening / closing member. , Image forming apparatus In a state of being removed from the body, the image carrier and the developer carrier are vertically arranged, and the image carrier and the developer carrier are horizontally arranged. It is provided so that it can be placed in any of the placement states, and a first contact portion that comes into contact with the placement surface in the vertically placed state, and abuts on the placement surface in the horizontally placed state. A second abutting portion, and the image carrier, the developer carrier, and the developer storage chamber are provided so as to overlap in the attaching / detaching direction of the process unit. A developing unit having a developer accommodating chamber and the developer carrying member; and an image carrying unit having the image carrying member. The developing unit and the image carrying unit are integrated with the image forming apparatus main body. It is removable The developing unit is detachably provided with respect to the image carrying unit, the first contact unit is provided on the image carrying unit, and the second contact unit is provided with the image carrying unit and the development unit. It is provided in each of the parts .

According to such a configuration, the process unit is provided with the image carrier, the developer carrier, and the developer storage chamber so as to overlap in the attaching / detaching direction of the process unit. The unit is attached to and detached from the image forming apparatus main body through an opening formed by opening the opening / closing member on the opposite side of the transfer position of the image carrier to which the developer image carried on the image carrier is transferred. Can do. Therefore, the exposure means is fixed to the image forming apparatus main body without being moved when the process unit is attached or detached, so that accurate exposure can be secured, and the process unit is fixed to the image forming apparatus main body. It can be smoothly attached to and detached from the image forming apparatus main body without interfering with the exposed exposure means. In addition, the process unit can be stably mounted in the vertically or horizontally placed state by the first contact portion and the second contact portion in a state where the process unit is detached from the image forming apparatus main body. Can be placed. Therefore, it is possible to prevent the process unit from overturning and to facilitate handling in either the vertically placed state or the horizontally placed state.
Further, according to such a configuration, since the developing unit can be attached to and detached from the image carrying unit, when the developer is empty, the used developing unit is detached from the image carrying unit, and then the image is obtained. If a new developing unit is mounted on the carrying unit, it is possible to replace only the developing unit without replacing an image carrying unit that is less frequently replaced. As a result, it is possible to reduce running costs and industrial waste. On the other hand, when replacing the image bearing member, the developing unit and the image bearing unit are detached from the main body of the image forming apparatus, and the developing unit is detached from the used image bearing unit. If the developing unit is attached to the carrying unit, and these are integrally attached to the image forming apparatus main body, the image carrying unit having a low replacement frequency can be easily replaced.

  According to a third aspect of the present invention, in the second aspect of the present invention, the process unit is a supply for supplying the developer contained in the developer containing chamber to the developer carrying member. The supply means is provided so as to overlap the image carrier, the developer carrier, and the developer storage chamber in the attaching / detaching direction of the process unit.

According to such a configuration, the supply unit is also provided so as to overlap the image carrier, the developer carrier, and the developer storage chamber in the attaching / detaching direction of the process unit. It can be more smoothly attached to and detached from the main body of the image forming apparatus without interfering with the fixed exposure means.
According to a fourth aspect of the present invention, in the invention of the second or third aspect, the image carrier and the developer carrier are provided in a projection plane in the attachment / detachment direction of the process unit in the developer storage chamber. It is characterized by being arranged.

  According to such a configuration, since the image carrier and the developer carrier are arranged in the projection plane in the process unit attachment / detachment direction in the developer storage chamber, the process unit is orthogonal to the process unit attachment / detachment direction. In the direction, it can be formed thin. Therefore, the process unit can be more smoothly attached to and detached from the image forming apparatus main body without interfering with the exposure unit fixed to the image forming apparatus main body.

According to a fifth aspect of the present invention, in the invention according to the third or fourth aspect, the supply means is accommodated in a projection surface of the developer accommodating chamber in the attachment / detachment direction of the process unit. It is a feature.
According to such a configuration, since the supply unit is disposed in the projection surface of the developer accommodating chamber in the process unit attaching / detaching direction, the process unit is formed thin in a direction perpendicular to the process unit attaching / detaching direction. be able to. Therefore, the process unit can be more smoothly attached to and detached from the image forming apparatus main body without interfering with the exposure unit fixed to the image forming apparatus main body.

According to a sixth aspect of the invention, there is provided the developer according to any one of the first to fifth aspects, wherein the developer is disposed above the image carrier in a state where the process unit is mounted on the main body of the image forming apparatus. A carrier is disposed, and the developer storage chamber is disposed above the developer carrier.
According to such a configuration, in a state where the process unit is mounted on the image forming apparatus main body, the developer carrier is disposed above the image carrier, and the developer storage chamber is disposed above the developer carrier. Therefore, gravity can be used to transport the developer in the developer storage chamber. Therefore, the developer conveying means in the developer accommodating chamber can be reduced, and the configuration can be simplified.

According to a seventh aspect of the present invention, in the invention according to any one of the third to sixth aspects, the supply means is provided between the developer carrier and the developer storage chamber. It is characterized by.
According to such a configuration, since the supply means is provided between the developer carrier and the developer storage chamber, the image forming apparatus is configured as a horizontal type in which the process units are arranged in parallel in the horizontal direction. However, it is possible to further reduce the space required for the horizontal installation area.

According to an eighth aspect of the invention, in the invention according to any one of the first to seventh aspects, the developing unit is provided detachably with respect to the image carrier mounted on the image forming apparatus main body. It is characterized by having.
According to such a configuration, the developing unit can be attached to and detached from the image carrying unit while the image carrying unit is mounted on the image forming apparatus main body. Only the developing unit can be exchanged without attaching or detaching the image carrying unit. Therefore, it is possible to facilitate replacement of the developing unit.

According to a ninth aspect of the present invention, in the invention according to any one of the first to eighth aspects, the engaging portion provided in the image carrying portion and the developing portion engageable with the engaging portion. And an engaged portion provided on the head.
According to such a configuration, the developing portion can be attached to and detached from the image carrying portion by engaging / disengaging the engaging portion provided in the image carrying portion and the engaged portion provided in the developing portion.

Further, the invention according to claim 1 0, in the invention described in claim 9, provided in the developing unit, an operating unit for releasing the engagement between the engaged portion and the engagement portion It is characterized by having.
According to such a configuration, engagement / disengagement between the engaging portion provided in the image carrying portion and the engaged portion provided in the developing portion can be operated in the operation portion of the developing portion. That is, the attaching / detaching operation of the developing unit with respect to the image carrying unit can be operated from the developing unit side. Therefore, the attachment / detachment work can be facilitated and the operability can be improved.

The invention of claim 1 1, in the invention described in any one of claims 1 to 1 0, provided in the image bearing unit, so that the developer carrier to the image carrier faces A first guide part for guiding the developing part and a first guided part provided in the developing part and guided by the first guide part are provided.
According to such a configuration, the first guided portion provided in the developing portion is guided by the first guide portion provided in the image carrying portion, whereby the developer carrying body is guided so as to face the image carrying body. The Therefore, the positional accuracy of the developer carrying member with respect to the image carrying member is good, and the formation of a good color image can be achieved.

The invention according to claim 1 2 is the invention according to claim 1 1, provided in the image forming apparatus main body, a second guide portion for guiding the attachment and detachment of the developing unit to the image forming apparatus main body It is characterized by being.
According to such a configuration, the attaching / detaching operation of the developing unit with respect to the image forming apparatus main body can be ensured by the second guide portion provided in the image forming apparatus main body.

The invention according to claim 1 3 is the invention according to claim 1 2, wherein the second guide portion, the image carrier by the first guided portion of the developing unit is attached to the image forming apparatus main body The second guided portion of the developing unit is guided so as to be guided to the guidance start position of the first guiding unit.
According to such a configuration, the developing unit is guided to the guidance start position of the first guiding unit by the second guide unit, and then the first guiding unit guides the developer carrier to a position facing the image carrier. Is done. Thus, even when the image carrier is mounted on the image forming apparatus main body, the developer carrier can be arranged with high positional accuracy with respect to the image carrier.

The invention as claimed in claims 1 to 4 is the invention according to claim 1 2 or 1 3, provided in the image forming apparatus main body, for guiding the attachment and detachment of the image bearing unit relative to the image forming apparatus main body It is characterized by having a third guide part.
According to such a configuration, it is possible to ensure the attaching / detaching operation of the image carrier with respect to the image forming apparatus main body by the third guide part provided in the image forming apparatus main body.

Further, an invention according to claim 1 5, in the invention described in claim 1 4, wherein the second guide portion and said third guide portion is provided substantially in parallel to the housing surface of the exposing unit It is characterized by that.
According to such a configuration, since the second guide portion and the third guide portion are provided substantially parallel to the surface of the casing of the exposure unit, the developing unit alone, or both the developing unit and the image carrying unit, It can be detached from between each exposure means.

Further, an invention according to claim 1 6, in the invention described in claim 1 4 or 1 5, housing surface of the exposure means, is characterized in that also serves as a guide member of the image bearing unit .
According to such a configuration, the housing surface of the exposure unit also serves as a guide member for the image carrier, so that the size of the apparatus can be reduced while reducing the number of parts and simplifying the apparatus configuration. it can.

The invention of claim 1 7, in the invention of any one of claims 1 4 and 1 6, wherein the second guide portion and the third guide portion, and the developing unit, the developer carrier It is provided so that it may oppose in the axial direction both sides of a body.
According to such a configuration, since the second guide portion and the third guide portion are provided so as to face the developing portion on both sides in the axial direction of the developer carrier, the image forming apparatus main body can be configured with a simple configuration. It is possible to guide the attachment and detachment of the developing unit and the image carrying unit with respect to the image forming unit.

Further, an invention according to claim 1 8, in the invention of any one of claims 1 4 to 1 7, at least one of the deepest portion of the deepest portion or the third guide portion of the second guide portion A buffer member for receiving the second guided portion of the developing unit or the guided portion of the image carrying unit is provided.
According to such a configuration, when the developing unit or the image carrying unit is mounted, the image forming apparatus includes the second guided unit of the developing unit or the guided unit of the image carrying unit, and the deepest part or the third of the second guiding unit. The collision with the deepest part of the guide part can be mitigated. Therefore, it is possible to prevent damage to the developer carrying member in the developing unit and the image carrying member in the image carrying unit.

The invention according to claim 19 is the invention according to any one of claims 6 to 18 , wherein the process unit has an image forming apparatus on a wall of the developer accommodating portion along the attaching / detaching direction of the process unit. In the state where it is attached to the main body, it is arranged in a substantially vertical direction, or is arranged so as to be inclined inwardly toward the inside of the developer accommodating portion.

  According to such a configuration, when the image forming apparatus is configured as a horizontal type in which the process units are arranged in parallel in the horizontal direction, the developer is stored in the developer storage chamber, and includes a developer storage unit. The developer in contact with the wall along the attaching / detaching direction of the process unit can be favorably moved in the direction of gravity. Therefore, the developer can be smoothly supplied from the developer storage chamber to the developer carrier.

The invention described in Claim 2 0 is the invention according to any one of claims 6 to 19, wherein provided on the side close to the developer carrier in the developing agent storage chamber, for stirring the developer It is characterized by having a stirring member.
According to such a configuration, when the image forming apparatus is configured as a horizontal type in which the process units are arranged in parallel in the horizontal direction, the developer moving in the gravity direction from the developer storage chamber is well stirred. It can be supplied to the developer carrier side.

The invention according to claim 2 1, in the invention described in any one of claims 1 to 2 0, provided in the process unit, in that it comprises a grip portion for gripping the process unit It is a feature.
If the process unit and the exposure unit are alternately arranged and the apparatus is downsized, a space for gripping the housing of the process unit is not provided when the process unit is attached or detached. By providing the grip, the process unit can be smoothly attached to and detached from the image forming apparatus main body by gripping the grip portion. Therefore, operability can be improved.

Further, an invention according to claim 2 2, in the invention described in claim 2 1, comprising an operation panel to be operated by the user, the grip portion includes a hook portion extending on the opposite side of the operation panel side It is characterized by having.
According to such a configuration, the user can grip the grip portion by hooking his / her hand on the hook portion provided on the side opposite to the operation panel side. Therefore, it is possible to firmly grip the grip portion.

Further, the invention according to claim 2 3, in the invention of any one of claims 1 to 2 2, wherein the process unit is disposed opposite to the image bearing member, for charging said image bearing member A charging unit, and the charging unit overlaps in an attachment / detachment position arranged so as to overlap in the attaching / detaching direction of the image carrier and the process unit, and in a direction crossing the attaching / detaching direction of the image carrier and the process unit. It is characterized in that it is provided so as to be movable at the mounting position arranged at the position.

  According to such a configuration, at the time of attachment / detachment, the charging unit is disposed so as to overlap in the attaching / detaching direction of the image carrier and the process unit. Therefore, the process unit can be attached / detached without the charging unit interfering with the exposure unit. . On the other hand, at the time of mounting, the charging unit is arranged so as to overlap in the direction intersecting with the attaching / detaching direction of the image carrier and the process unit. And the process unit can be arranged so as to overlap in the attaching / detaching direction.

Further, an invention according to claims 2 to 4, the invention according to claim 2 3, wherein the charging means is the detachment position, characterized in that serves as the first contact portion.
According to such a configuration, since the charging means also serves as the first contact portion, it is possible to reduce the number of parts and simplify the device configuration.
The invention according to claim 2 5, in the invention described in any one of claims 1 to 2 4, one wall disposed on both longitudinal ends of the developer carrier in the developer containing portion Is characterized in that a filling port for filling the developer is provided on the side far from the developer carrying member.

  According to such a configuration, since the filling port is provided on one side of the wall disposed on both sides in the longitudinal direction of the developer carrier in the developer accommodating portion, on the side far from the developer carrier, the developer At the time of filling, it is possible to satisfactorily fill the developer along the longitudinal direction of the developer carrier in the developer accommodating portion while preventing interference between the filled developer and other members. Therefore, the workability at the time of toner filling can be improved.

The invention according to claim 2 6, in the invention described in any one of claims 1 to 2 5, the image bearing member after the developer image carried on the image carrier is transferred onto the transfer medium The developer remaining thereon is collected by the developer carrier.
According to such a configuration, after the developer image is transferred to the transfer medium, the developer remaining on the image carrier is collected by the developer carrier, so that the developer remaining on the image carrier is collected. Therefore, it is not necessary to provide a storage means for doing so, and the apparatus configuration can be simplified and the apparatus can be downsized. Therefore, a configuration in which the process unit can be attached and detached without moving the exposure unit can be easily realized. In addition, when such storage means is provided integrally with the image carrier, the life of the image carrier is determined by the capacity of the storage means, and either the longer life of the image carrier or the miniaturization of the apparatus can be achieved. However, in the configuration of the present invention, it is possible to achieve both.

Further, an invention according to claim 2 7, in the invention of any one of claims 1 to 2 6, the developer is characterized in that a toner having a substantially spherical shape.
According to such a configuration, since the developer is a substantially spherical toner, the fluidity is good and a good image can be formed.

According to the first aspect of the present invention, since the exposure means is fixed to the image forming apparatus main body without being moved when the process unit is attached / detached, accurate exposure can be ensured, and further, the process can be performed. The unit can be smoothly attached to and detached from the image forming apparatus main body without the interference of the exposure means fixed to the image forming apparatus main body. Further, in either of the vertically placed state and the horizontally placed state, it is possible to prevent the process unit from being overturned and facilitate handling. In addition, it is possible to reduce running costs and industrial waste.

According to the second aspect of the present invention, since the exposure means is fixed to the image forming apparatus main body without being moved when the process unit is attached or detached, accurate exposure can be ensured, and further, the process can be performed. The unit can be smoothly attached to and detached from the image forming apparatus main body without the interference of the exposure means fixed to the image forming apparatus main body. Further, in either of the vertically placed state and the horizontally placed state, it is possible to prevent the process unit from being overturned and facilitate handling. In addition, it is possible to reduce running costs and industrial waste.

According to the third aspect of the present invention, the image forming apparatus main body can be attached and detached more smoothly.
According to invention of Claim 4, a process unit can be formed thinly in the direction orthogonal to the attachment or detachment direction of a process unit. Therefore, the process unit can be more smoothly attached to and detached from the image forming apparatus main body without interfering with the exposure unit fixed to the image forming apparatus main body.

According to the fifth aspect of the present invention, the process unit can be thinly formed in a direction orthogonal to the process unit attaching / detaching direction. Therefore, the process unit can be more smoothly attached to and detached from the image forming apparatus main body without interfering with the exposure unit fixed to the image forming apparatus main body.
According to the sixth aspect of the present invention, the number of developer conveying means in the developer containing chamber can be reduced, and the configuration can be simplified.

According to the seventh aspect of the present invention, it is possible to further reduce the installation space in the horizontal direction .
According to the invention described in 請 Motomeko 8, it is possible to facilitate the replacement of the developing unit.

According to the ninth aspect of the present invention, the developing unit can be attached to and detached from the image bearing unit.
According to the invention of claim 1 0, it is possible to improve the ease and manipulation of mounting and dismounting.
According to the invention of claim 1 1, can be positioned accurately with respect to the image carrier of the developer carrying member is often to achieve formation of a good color image.

According to the invention of claim 1 2, it is possible to secure the removable operation of the developing unit.
According to the invention described in claims 1 to 3, even if the image bearing member is attached to the image forming apparatus main body, it can be arranged with high positional accuracy developer carrier against the image bearing member.
According to the invention described in claims 1 to 4, it is possible to secure the removable operation of the image bearing unit.
According to the invention described in claim 1 5, the developing unit alone or both the developing unit and the image carrying unit, from between the exposure means may be detachable.

According to the invention described in claim 16 , it is possible to reduce the size of the apparatus while reducing the number of parts and simplifying the apparatus configuration.
According to the invention described in claim 17 , it is possible to guide the attachment and detachment of the developing unit and the image carrier with respect to the image forming apparatus main body with a simple configuration.
According to the invention described in claim 18 , it is possible to prevent damage to the developer carrying member of the developing unit and the image carrying member of the image carrying unit.

According to the nineteenth aspect of the invention, the developer can be smoothly supplied from the developer storage chamber to the developer carrying member.
According to the invention of claim 2 0, the developer that moves from the developer accommodating chamber in the direction of gravity can be supplied to the side of the developer carrying member satisfactorily stirring.
According to the invention described in claim 2 1, it is possible to improve the operability.

According to the invention of claim 2 2, it is possible to firmly grip the grip portion.
According to the invention of claim 2 3, at the time of detachment, without charging unit from interfering with the exposure means, it is possible to attach and detach the process unit. Further, at the time of mounting, the charging unit can be arranged so as to overlap in the attaching / detaching direction of the exposure unit and the process unit.

According to the invention of claim 2 4, it is possible to simplify the reduction and device configuration of the parts.
According to the invention described in claim 25 , the workability at the time of toner filling can be improved.
According to the invention described in claim 26 , it is possible to easily realize a configuration in which the process unit is attached and detached without moving the exposure means. It is possible to achieve both a long life of the image carrier and a reduction in the size of the apparatus.

According to the invention of claim 2 7, it is possible to form a favorable image.

FIG. 1 is a cross-sectional side view of an essential part showing an embodiment of a color laser printer as an image forming apparatus of the present invention.
1, the color laser printer 1 is a so-called horizontal type tandem color laser printer in which four process units 14 to be described later are arranged in parallel in the horizontal direction. A sheet feeding unit 4 for feeding a sheet 3 as a transfer medium to the main body casing 2, an image forming unit 5 for forming an image on the fed sheet 3, and a sheet 3 on which an image is formed are discharged. A paper discharge unit 6 for paper is provided.

  The main body casing 2 has a rectangular box shape with a top opened, and a top cover 7 is provided on the upper side. The top cover 7 is disposed on the opposite side of the transfer position of the photosensitive drum 44, which will be described later, in contact with the conveyance belt 56 of the transfer unit 15, and the rear side of the main casing 2 (in the following description, the left side in FIG. , The right side is the front side), and is rotatably supported via a hinge 7a provided on the main casing 2 so as to be openable and closable as indicated by an imaginary line.

  The top cover 7 is provided with a paper discharge port 9 for discharging the paper 3 and a concave discharge with the paper discharge port 9 side recessed more deeply in order to stack the paper 3 discharged from the paper discharge port 9. A paper tray 10 and a paper discharge roller 8 provided at the rear end of the paper discharge tray 10 at the paper discharge port 9 are provided. The paper discharge port 9, the paper discharge tray 10, and the paper discharge roller 8 are moved together with the top cover 7 when the top cover 7 is opened and closed.

An operation panel 90 is provided at the front end of the top cover 7 so that the user can set various setting items of the color laser printer 1.
The paper feed unit 4 includes a paper feed tray 11 that is detachably attached to the main body casing 2 in the horizontal direction from the front side at the bottom of the main body casing 2, and an upper part of the paper feed tray 11 (upper front side). A paper feed roller 12 provided above the paper feed roller 12 and downstream of the paper feed roller 12 in the transport direction of the paper 3 (hereinafter, downstream of the paper 3 in the transport direction or upstream of the paper 3 in the transport direction). The side is sometimes referred to as the downstream side in the transport direction or the upstream side in the transport direction).

The sheets 3 are stacked in the sheet feed tray 11, and the sheet 3 at the top is fed one by one toward the transport roller 13 in the vertical direction by the rotation of the sheet feed roller 12. Then, the toner is sequentially sent from the conveying roller 13 to the space between the conveying belt 56 and each photosensitive drum 44 (transfer position).
A guide member 13a is provided between the paper feed roller 12 and the transport roller 13 in the vertical direction. The paper 3 fed by the paper feed roller 12 is transported by the guide member 13a. 13, and is sequentially fed from the conveyance roller 13 between the conveyance belt 56 and the photosensitive drums 44 (transfer positions) disposed behind the conveyance roller 13.

The image forming unit 5 includes a process unit 14, a transfer unit 15, and a fixing unit 60.
The process unit 14 is provided for each color of a plurality of colors of toner. In other words, the process unit 14 includes four units, that is, a yellow process unit 14Y, a magenta process unit 14M, a cyan process unit 14C, and a black process unit 14K. These process units 14 are sequentially arranged in parallel so as to overlap in the horizontal direction at a predetermined interval from the front side to the rear side.

Each process unit 14 includes a scanner unit 17 and a process unit 16 as exposure means.
The scanner unit 17 is disposed at a predetermined interval from the conveyance belt 56 in the vertical direction, and is fixed to the main body casing 2 for each scanner unit 17. As shown in FIG. 2A, a scanner unit 17 includes a laser light emitting unit (not shown), a polygon mirror 21, two lenses 22 and 23, and three reflecting mirrors 24 in a scanner casing 20 as a housing. , 25 and 26.

  The scanner casing 20 is formed in an elongated box shape, and a scanner side guide portion 28 for integrally guiding the photosensitive drum unit 19 when the photosensitive drum unit 19 is attached and detached is integrally formed on the rear wall of the scanner casing 20. The scanner-side guide portion 28 is provided on the rear wall so as to extend from the middle of the scanner casing 20 in the vertical direction to the vicinity of the conveyor belt 56, and the upper end portion of the scanner-side guide portion 28 bulges rearward gradually downward. Is formed.

Further, as shown in FIG. 3A, the scanner-side guide portion 28 has a cover of a drum casing 43, which will be described later, in a substantially central portion in the width direction (a direction perpendicular to the vertical direction when viewed from the front, the same shall apply hereinafter). A guide groove 29 slidably engaged with the boss portion 61 of the portion 47 extends in the vertical direction and is formed in a concave shape in the front.
As shown in FIG. 2A, the front wall of the scanner casing 20 is formed in a flat shape, and an emission window 30 through which laser light is emitted is formed in the vicinity of the lower end portion thereof.

  In the scanner unit 17, the laser light (see the chain line in FIG. 1) based on the image data emitted from the laser emitting unit is reflected by the polygon mirror 21, and the lens 22, the reflecting mirror 24, the reflecting mirror 25, and the lens 23. Then, the light passes through or reflects through the reflecting mirror 26 and is emitted from the exit window 30. Laser light emitted from the emission window 30 is applied to the photosensitive drum 44 by high-speed scanning.

  Further, as shown in FIG. 1, the scanner units 17 are arranged at substantially the same position in the vertical direction, that is, arranged so as to overlap each other in the horizontal direction. More specifically, each scanner unit 17 is disposed behind and corresponding to each process unit 16, that is, each process unit 16 and each scanner unit 17 are alternately overlapped in the horizontal direction. Is arranged.

The process unit 16 includes a developing unit 18 as a developing unit and a photosensitive drum unit 19 as an image carrying unit, and is detachably attached to the main casing 2.
As shown in FIG. 2A, the developing unit 18 includes, in a developing casing 31, a toner hopper 32 as a developer container, a supply roller 33 as a supply unit, a development roller 34 as a developer carrier, and a layer thickness. A regulating blade 35 is provided.

Further, the developing unit 18 includes a developing roller 34, a supply roller 33, a stirring member, and an agitator 38 as a developer conveying means arranged in a vertical direction, and each developing unit 18 has a vertical direction with respect to the main body casing 2. It is attached detachably.
The developing casing 31 is formed in an elongated box shape whose lower side is opened, and a grip portion 36 for gripping the developing casing 31 is provided on the upper wall thereof. The grip part 36 is formed so as to protrude upward in a triangular shape in a side view from the upper wall of the developing casing 31. Further, a hook-shaped hooking portion 36 a is integrally provided at the upper end portion of the gripping portion 36. When the top cover 7 is opened from the front side, the hook portion 36a extends so that the user extends to the side opposite to the side to be accessed, that is, to the rear side opposite to the operation panel 90 side. Is formed.

Further, the rear wall of the developing casing 31 is arranged in a vertical direction and is formed in a planar shape parallel to the front wall of the scanner casing 20 formed in a planar shape.
Further, the front wall of the developing casing 31 is arranged in the vertical direction, the corner portion of the upper end portion thereof is formed in a curved shape in a side view continuous with the upper wall, and the lower portion of the agitator 38 provided in the toner hopper 23 is rotated. It is formed in a curved shape toward the rear side in a side view so as to follow the locus. Further, the lower end portion of the front wall is a covering portion that covers the supply roller 33 and the developing roller 34. Further, a second contact portion 39 that protrudes forward is provided in the vicinity of a position corresponding to the agitator 38 on the front wall. The second contact portion 39 is formed as a protrusion extending in the width direction of the developing casing 31.

  Further, the side walls on both sides in the width direction of the developing casing 31 are arranged in the vertical direction and are slidable in a main body side first guide groove 62 (see FIG. 5) of the main body casing 2 described later, as shown in FIG. A development-side guide projection 37 is provided as a second guided portion that is engaged with the. The development-side guide protrusions 37 are arranged on both side walls of the development casing 31 at a predetermined interval in the vertical direction, and both in the width direction in the vicinity of the position corresponding to the development roller 34 and in the vicinity of the upper portion of the toner hopper 32. It is formed so as to protrude outward. The developing-side guide protrusion 37 provided in the vicinity of the position corresponding to the developing roller 34 is removed from the main casing 2 and placed vertically with respect to the mounting surface 71 (see FIG. 7), as will be described later. When placed, it is disposed so as to abut on the upper end portion of the side plate 49 of the photosensitive drum unit 43.

  Engaging levers 40 (only one side is shown in FIG. 4) are provided on both side walls of the developing casing 31 as engaged portions. The engaging lever 40 has a hook-like shape extending in the vertical direction, and its upper end is formed as a flat operation portion 41, and its lower end is a locking groove formed in a side plate 49 of a drum casing 45 described later. 52 (only one side is shown in FIG. 4). The engaging lever 40 is rotated around a rotating shaft 40a (only one side is shown in FIG. 4) provided so as to protrude outward in the width direction in the vicinity of a position corresponding to the agitator 38 on both side walls. It is supported freely. The engaging lever 40 is applied in a direction in which the claw portion 42 engages with the engaging groove 52, that is, in a counterclockwise direction in FIG. 4, by a spring (not shown) provided in the developing casing 31. It is energized.

  In addition, on one side wall of the developing casing 31, a filling port 32 a for filling the toner hopper 32 with toner is provided in the vicinity of the upper portion far from the agitator 38. If the filling port 32 a is provided on the side wall of the developing casing 31 far from the agitator 38, the toner to be filled does not interfere with the agitator 38 when the toner is filled, and extends along the width direction of the developing casing 31. The toner can be satisfactorily filled. Therefore, the workability at the time of toner filling can be improved. A cap 32b that covers the filling port 32a is attached to the filling port 32a.

  As shown in FIG. 2A, the toner hopper 32 is formed as an internal space of the developing casing 31. The toner hopper 32 is provided with an agitator 38 on the side close to the developing roller 34, and contains toner as a developer for each color. That is, in the toner hopper 32, as toner, for each process unit 14, yellow for the yellow process unit 14Y, magenta for the magenta process unit 14M, cyan for the cyan process unit 14C, and black for the black process unit 14K. A positively charged non-magnetic one-component polymer toner having a color is accommodated. Such a polymerized toner is manufactured by a suspension polymerization method or an emulsion polymerization method, has a substantially spherical shape, and has extremely good fluidity.

The supply roller 33 is disposed below the toner hopper 32, and a metal roller shaft is covered with a roller portion made of a conductive sponge member. The supply roller 33 is supported in a counterclockwise direction so as to rotate in a direction opposite to the developing roller 34 at a nip portion facing the developing roller 34.
The developing roller 34 is disposed below the supply roller 33 so as to be compressed with the supply roller 33. In the developing roller 34, a metal roller shaft 67 serving as a first guided portion is covered with a roller portion made of an elastic member such as a conductive rubber material. More specifically, the roller portion of the developing roller 34 is covered with an elastic roller portion made of conductive urethane rubber, silicone rubber, EPDM rubber or the like containing carbon fine particles, and the surface of the roller portion. It is formed by a two-layer structure with a coat layer mainly composed of rubber, urethane resin, polyimide resin or the like.

  The developing roller 34 has a roller shaft 67 that rotates in the same direction as the photosensitive drum 44 at a nip portion facing the photosensitive drum 44, and a drum side guide groove 51 of the drum casing 43 (see FIG. 4). In the vicinity of the lower end of the shaft, it is rotatably supported in the counterclockwise direction. That is, the roller shaft 67 of the developing roller 34 is provided so as to protrude outward in the width direction, and is slidably engaged with a drum-side guide groove 51 described later. A developing bias is applied to the developing roller 34 from a power source (not shown) during development.

  Further, the layer thickness regulating blade 35 includes a pressing portion having a semicircular cross section made of insulating silicone rubber at the tip of a blade body made of a metal leaf spring member. The layer thickness regulating blade 35 has a base end portion of the blade body supported by the developing casing 31 at the rear between the supply roller 33 and the developing roller 34, and a pressing portion provided at the tip end portion of the blade body has a blade The rear upper portion of the developing roller 33 is press-contacted by the elastic force of the main body so as to be in contact with each other.

  The toner accommodated in the toner hopper 32 is moved downward by its own weight and is supplied to the supply roller 33 while being stirred by the rotation of the agitator 38. The toner supplied to the supply roller 33 is supplied to the developing roller 34 by the rotation of the supply roller 33. At this time, the toner is positively frictionally charged between the supply roller 33 and the developing roller 34. Further, the toner supplied onto the developing roller 34 enters between the pressing portion of the layer thickness regulating blade 35 and the developing roller 34 as the developing roller 34 rotates, and is developed as a thin layer having a constant thickness. It is carried on a roller 34.

The developing units 18 are arranged at substantially the same position in the vertical direction, that is, arranged so as to overlap each other in the horizontal direction. More specifically, the developing units 18 and the scanner units 17 are arranged above the paper feed tray 11 so as to alternately overlap in the horizontal direction.
The photosensitive drum unit 19 is detachably attached to the main body casing 2 for each photosensitive drum unit 19. In the drum casing 43, a photosensitive drum 44 as an image carrier and a scorotron charger 45 as a charging unit are provided. I have.

As shown in FIGS. 2 (a) and 4 (a), the drum casing 43 has a rectangular frame-shaped drum housing portion 46 that is open in a vertical direction and extends upward from the drum housing portion 46. A cover portion 47 that is U-shaped in plan view and is open is integrally formed.
The rear wall of the drum accommodating portion 46 is formed in a flat plate shape that is substantially flush with the rear wall of the developing casing 31. Further, the front wall is formed in an arc shape in a side view along the outer peripheral surface of the photosensitive drum 44, and a second abutting portion 48b protruding forward is formed at the upper end portion and the lower end portion of the front wall. Each is provided. The second contact portion 48 b is formed at both ends in the width direction of the drum housing portion 46. That is, four second contact portions 48 b are provided on the front wall of the drum housing portion 46.

  A first abutting portion 48 a that protrudes downward is provided at the lower end portion of the front wall and the lower end portion of the rear wall of the drum housing portion 46, respectively. As shown in FIG. 3B, the first abutting portion 48a has a width of the drum accommodating portion 46 with a photosensitive drum 44 and a later-described conveying belt 56 and transfer roller 57 disposed opposite to the photosensitive drum 44 interposed therebetween. It is formed so as to protrude below the photosensitive drum 44 at both ends in the direction. That is, four first contact portions 48 a are provided at the lower end portion of the drum housing portion 46 on the front wall and the rear wall.

Further, as shown in FIG. 4A, the cover portion 47 is continuous from both side walls of the drum housing portion 46 and is connected to a side plate 49 provided opposite to each other and a front end portion of each side plate 49. The plate 50 is integrally formed.
The side plate 49 is formed in an L shape such that the upper end on the rear side extends in the horizontal direction, and the upper end on the front side extends above the upper end on the rear side, and between the rear side and the front side. In the middle of the front-rear direction, a drum-side guide groove 51 is formed as a first guide portion that is recessed downward in an elongated U shape. Further, a locking groove 52 as a notch-shaped engaging portion that is recessed forward is formed in the middle of the drum-side guide groove 51 in the vertical direction. In addition, a drum-side guide protrusion 53 as a guided portion that is slidably engaged with a body-side third guide groove 65 (see FIG. 5) of the body casing 2 described later is provided in front of the upper end portion of the side plate 49. It protrudes toward both outer sides in the width direction.

  A boss portion slidably engaged with a guide groove 29 (see FIG. 3A) of the scanner-side guide portion 28 of the scanner unit 17 is provided at a substantially central portion in the width direction in the middle of the front plate 50 in the vertical direction. 61 is formed so as to protrude forward. Further, a second abutting portion 48 b that protrudes forward is provided at the upper end portion of the front plate 50. The second contact portions 48 b are formed at both ends in the width direction of the front plate 50 of the cover portion 47. That is, the front plate 50 is provided with two second contact portions 48b.

Each of the second contact portions 48b formed on the drum casing 43 is formed so that the free end portion thereof is substantially flush with the horizontal direction, and the boss portion 61 is formed of each of the second contact portions 48b. It is smaller than 48b and protrudes forward.
As shown in FIG. 2, the photosensitive drum 44 is made of a cylindrical metal tube made of aluminum or the like, and the surface thereof is coated with a photosensitive layer made of an organic photosensitive member mainly composed of polycarbonate. The photosensitive drum 44 is disposed below the developing roller 34 so as to be opposed to the developing roller 34, and is accommodated in the drum so as to rotate in the same direction as the conveying belt 56 at a nip portion facing the conveying belt 56. On both side walls of the portion 46, it is rotatably supported via a rotating shaft 63 as a guided portion.

The rotating shaft 63 is provided so as to protrude further outward in the width direction from both side walls of the drum housing portion 46, and is slidably engaged with a body-side second guide groove 64 (see FIG. 5) described later. Combined.
Further, the scorotron charger 45 is arranged behind the photosensitive drum 44 with a predetermined distance from the photosensitive drum 44. The scorotron charger 45 is fixed to the rear wall of the drum housing portion 46. The scorotron charger 45 is a positively charged scorotron charger that generates corona discharge from a charging wire such as tungsten, and the surface of the photosensitive drum 44 is made uniform by applying a voltage from a power source (not shown). It is provided so that it can be charged positively.

  When the photosensitive drum 44 is rotated, first, the surface of the photosensitive drum 44 is positively charged uniformly by the scorotron charger 45. Thereafter, as the photosensitive drum 44 rotates, the surface of the photosensitive drum 44 is scanned with laser light from the scanner unit 17 at a high speed, thereby forming an electrostatic latent image based on the image data. After that, when facing the developing roller 34, the positively charged toner carried on the developing roller 34 is electrostatically charged on the surface of the photosensitive drum 44, that is, uniformly charged positively. The surface of the photosensitive drum 44 is exposed to a laser beam and electrically moved to a portion where the electric potential is lowered to be visualized, whereby reversal development is achieved. As a result, a toner image for each color is formed on the photosensitive drum 44.

The photosensitive drum units 19 are arranged at substantially the same position in the vertical direction, that is, arranged so as to overlap each other in the horizontal direction. Each photosensitive drum unit 19 is arranged such that each photosensitive drum unit 19 overlaps with each developing unit 18 in the vertical direction in a state where each developing unit 18 is mounted.
More specifically, in a state where each photosensitive drum unit 19 and each developing unit 18 are mounted on the main body casing 2, the developing roller 34 is disposed above the photosensitive drum 44, and the supply roller 33 is above the developing roller 34. The toner hopper 32 is disposed above the supply roller 33. Further, the photosensitive drum 44, the developing roller 34, the supply roller 33, and the toner hopper 32 are provided so as to overlap in the vertical direction, which is the attaching / detaching direction of the photosensitive drum unit 19 and the developing unit 18. Further, the photosensitive drum 44 and the scorotron charger 45 are disposed in the vertical projection surface of the toner hopper 32, and the roller portion of the developing roller 34 and the roller portion of the supply roller 33 are disposed in the vertical projection surface of the photosensitive drum 44. Is arranged.

As shown in FIG. 1, the transfer unit 15 is provided in the main casing 2 so as to face each photosensitive drum 44 on the opposite side of each developing unit 18 in each photosensitive drum 44 arranged in the horizontal direction. Yes. The transfer unit 15 includes a driving roller 54, a driven roller 55, a transport belt 56 formed of an endless belt, and a transfer roller 57.
The drive roller 54 is disposed in front of the photosensitive drum 44 of the yellow process unit 14Y and on the upper rear side of the paper feed roller 12. The driven roller 55 is disposed behind the photosensitive drum 44 of the black process unit 14 </ b> K and obliquely below and below the fixing unit 60.

Further, the transport belt 56 is made of a resin such as conductive polycarbonate or polyimide in which conductive particles such as carbon are dispersed, and is wound between the driving roller 54 and the driven roller 55. The conveyor belt 56 is disposed such that the outer contact surface that is wound is in contact with the entire photosensitive drum 44 of each process unit 14.
Then, the driven roller 55 is driven by the driving roller 54, and the conveying belt 56 is photosensitive between the driving roller 54 and the driven roller 55 on the contact surface facing the photosensitive drum 44 of each process unit 14. It is rotated counterclockwise so as to rotate in the same direction as the drum 44.

  Further, the transfer roller 57 is provided so as to face the photosensitive drum 44 of each process unit 14 with the conveyance belt 56 interposed therebetween in the wound conveyance belt 56. The transfer roller 57 has a metal roller shaft covered with a roller portion made of an elastic member such as a conductive rubber material. Further, the transfer roller 57 is provided so as to be able to rotate counterclockwise so as to rotate in the same direction as the circumferential movement direction of the transport belt 56 on the contact surface facing and contacting the transport belt 56. A transfer bias is applied from a power source (not shown).

  The sheet 3 fed from the sheet feeding unit 4 is rotated by the conveying roller 13 by the driving roller 54 and the driven roller 55, and the photosensitive drum 44 of each process unit 14. The toner images of the respective colors formed on the photosensitive drums 44 of the respective process units 14 are sequentially transferred during the passage, whereby a color image is formed on the paper 3. .

  That is, for example, when a yellow toner image formed on the photosensitive drum 44 of the yellow process unit 14Y is transferred to the paper 3, then a magenta toner image formed on the photosensitive drum 44 of the magenta process unit 14M. However, the cyan toner image formed by the cyan process unit 14C and the black toner image formed by the black process unit 14 are transferred to the paper 3 on which the yellow toner image has already been transferred. Are superimposed and transferred, whereby a color image is formed on the paper 3.

In the formation of such a color image, the color laser printer 1 has a tandem apparatus configuration that includes a photosensitive drum 44 for each color. Therefore, the toner image for each color is formed at substantially the same speed as that for forming a monochrome image. To achieve rapid color image formation.
The fixing unit 60 is provided behind the process unit 14 and the transfer unit 15 and on the downstream side in the conveyance direction of the paper 3. The fixing unit 60 includes a heating roller 59 and a pressing roller 58. The heating roller 59 is made of a metal base tube having a release layer formed on the surface thereof, and a halogen lamp is provided along the axial direction thereof. Then, the surface of the heating roller 59 is heated to the fixing temperature by the halogen lamp. The pressing roller 58 is provided so as to press the heating roller 59.

The color image transferred onto the paper 3 is heat-fixed in the fixing unit 60 while the paper 3 passes between the heating roller 59 and the pressing roller 58.
The paper discharge unit 6 includes the paper discharge roller 8, the paper discharge port 9, and the paper discharge tray 10 described above. The thermally fixed paper 3 is discharged from the paper discharge port 9 to the outside of the main casing 2 by the paper discharge roller 8 and stacked on the paper discharge tray 10.

  In the color laser printer 1, the transfer residual toner is collected by a so-called cleanerless development system in which the transfer residual toner remaining on the photosensitive drum 44 after the transfer is collected by the developing roller 34 in each process unit 14. I am doing so. That is, in the cleanerless development method, after the transfer, the surface of the photosensitive drum 44 having the transfer residual toner is charged at a charging position facing the scorotron charger 45 by the rotation of the photosensitive drum 44, and then The exposure is performed by the scanner unit 17. The untransferred toner in the unexposed portion that has not been exposed is electrically collected by the developing roller 34 when the surface of the photosensitive drum 44 faces the developing roller 34. On the other hand, in the exposed portion, a toner image is formed by the transfer residual toner and the toner from the developing roller 34.

  According to such a cleanerless developing system, a waste toner storage unit for collecting and storing the transfer residual toner can be made unnecessary. Therefore, the development unit 18 and the photosensitive drum unit 19 can be reduced in size by simplifying the apparatus configuration and eliminating the space for providing the waste toner storage unit. Therefore, the developing unit 18 and the photosensitive drum unit 19 can be attached and detached from the side opposite to the transfer side without moving the scanner unit 17. In addition, when the waste toner storage unit is provided integrally with the photosensitive drum unit 19, the life of the photosensitive drum unit 19 is determined by the capacity of the waste toner storage unit, thereby extending the life of the photosensitive drum unit 19 and reducing the size of the apparatus. Either of these cannot be achieved, but if configured in this way, it is possible to achieve both.

In this embodiment, the developing roller 34 rotates with respect to the photosensitive drum 44 at a peripheral speed 1.6 times. The difference in peripheral speed makes it easy to collect the transfer residual toner from the photosensitive drum 44 to the developing roller 34.
Further, in this color laser printer 1, a substantially spherical polymerized toner having good fluidity is used as the toner, so that the transfer residual toner can be efficiently collected by the cleanerless development system while forming a good image. Have achieved.

  In the color laser printer 1, side plates 66 (see FIG. 3A) are provided on both sides in the width direction inside the main body casing 2, and each side plate 66 corresponds to each process unit 14. Then, as shown in FIG. 5, the development side guide protrusion 37 of the development casing 31 is slidably engaged with the main body side first guide groove 62 as a second guide portion, and the rotating shaft 63 of the photosensitive drum 44. A main body side second guide groove 64 and a main body side third guide groove 65 are formed as third guide portions to which the drum side guide protrusions 53 of the drum casing 43 are slidably engaged.

  Each main body side first guide groove 62 is formed to face each side plate 66 so that the developing casing 31 is arranged in parallel at a predetermined interval in front of the scanner casing 20. The upper end portion of the main body side first guide groove 62 is formed so as to open upward in the open state of the top cover 7. Further, the lower end portion of the main body side first guide groove 62 is developed when the roller shaft 67 of the developing roller 34 is disposed at the front end open portion (that is, the guide start position) of the drum side guide groove 51 of the drum casing 43. It is formed so as to be opened downward at a position where the developing side guide projection 37 on the lower side of the casing 31 is disposed, and a vertical direction is formed between the upper end portion and the lower end portion.

  Each main body side second guide groove 64 is formed to face each side plate 66 so as to be arranged in parallel with a predetermined interval in front of each main body side first guide groove 62 ( (See FIG. 3 (a)). The upper end portion of the main body side second guide groove 64 is formed so as to open upward in the open state of the top cover 7. Further, the lower end portion of the main body side second guide groove 64 is U-shaped in a side view at a position where the rotating shaft 63 of the photosensitive drum 44 abuts when the photosensitive drum 44 is disposed so as to face and contact the conveyance belt 56. The upper end and the lower end are formed in the vertical direction.

  Further, each main body side third guide groove 65 is formed to face each side plate 66 so as to be arranged in parallel with a predetermined interval in front of each main body side second guide groove 64. The upper end portion of the main body side third guide groove 65 is formed to open upward in the open state of the top cover 7, and the lower end portion of the main body side third guide groove 65 is rotated by the photosensitive drum 44. When the shaft 63 hits the lower end of the main body side second guide groove 64, the drum side guide projection 53 of the drum casing 43 is formed in a U shape in a side view so that the upper end and the lower end The space is formed in the vertical direction.

  In the color laser printer 1, the developing unit 18 can be attached to and detached from the photosensitive drum unit 19, and the developing unit 18 and the photosensitive drum unit 19 can be attached to and detached from the main body casing 2. The developing unit 18 can be attached to and detached from the photosensitive drum unit 19 with the photosensitive drum unit 19 mounted on the main casing 2.

  The attachment / detachment of the developing unit 18 with respect to the photosensitive drum unit 19 will be described with reference to FIG. When the developing unit 18 is attached to the photosensitive drum unit 19 in a state where it is removed from the main casing 2, the developing casing 31 is first detached from the drum casing 43 shown in FIG. The operating portion 41 of the engaging lever 40 is moved forward against the biasing force of the spring, and the engaging lever 40 is rotated to position the claw portion 42 rearward. Thereafter, by inserting the developing unit 18 downward with respect to the photosensitive drum unit 19, the roller shaft 67 of the developing roller 34 is inserted into the drum-side guide groove 51 of the drum casing 43 as shown in FIG. Then, the roller shaft 67 is inserted to the lower end portion of the drum side guide groove 51. Thereafter, when the hand is released from the operation unit 41, the operation unit 41 is moved backward by the biasing force of the spring. As a result, the claw portion 42 of the engagement lever 40 is engaged in the locking groove 52 of the drum casing 43, thereby developing the photosensitive drum unit 19 with the developing roller 34 facing the photosensitive drum 44. A unit 18 is mounted.

  The engaging groove 52 is configured so that the developing unit 18 is slightly movable in the vertical direction with respect to the photosensitive drum unit 19, for example, about 1 mm when engaged with the claw portion 42. The claw portion 42 is formed in such a size that it can move about 1 mm in the vertical direction. In this state, the drum-side guide groove 51 is formed such that the roller shaft 67 of the developing roller 34 is moved freely at the lower end portion of the drum-side guide groove 51.

  Further, when the developing unit 18 is detached from the photosensitive drum unit 19 in a state where it is detached from the main body casing 2, first, the developing casing 31 is mounted on the drum casing 43 shown in FIG. From the state, the operation portion 41 of the engagement lever 40 is moved forward against the urging force of the spring, and the engagement lever 40 is rotated to release the engagement of the claw portion 42 with the locking groove 52. . Thereafter, the developing unit 18 is pulled upward with respect to the photosensitive drum unit 19 so that the roller shaft 67 of the developing roller 34 is directed upward from the drum-side guide groove 51 of the drum casing 43 as shown in FIG. Evacuate. Then, the roller shaft 67 of the developing roller 34 is pulled out from the drum-side guide groove 51 of the drum casing 43, whereby the developing unit 18 is detached from the photosensitive drum unit 19.

By attaching and detaching in this way, the developing unit 18 can be attached to and detached from the photosensitive drum unit 19 by engaging and disengaging the claw portion 42 of the engaging lever 40 provided in the developing casing 31 and the engaging groove 52 provided in the drum casing 43. Can be planned.
In such attachment and detachment, the engagement / disengagement between the claw portion 42 and the locking groove 52 can be operated by the operation portion 41 of the engagement lever 40 of the developing casing 31. That is, the attaching / detaching operation of the developing unit 18 with respect to the photosensitive drum unit 19 can be operated from the upper side. Therefore, the attachment / detachment work can be facilitated and the operability can be improved.

  The development unit 18 and the photosensitive drum unit 19 are integrally attached to and detached from the main body casing 2, for example, in a state where the development unit 18 is mounted on the photosensitive drum unit 19 so that the black process unit 14K is referred to in FIG. First, the top cover 7 is opened, and the photosensitive drum unit 19 and the developing unit 18 that are attached to each other are attached to the main body side from the upper opening of the main body casing 2 formed by the opened top cover 7. The developing guide 31 of the developing casing 31 is engaged with the first guide groove 62, the rotating shaft 63 of the photosensitive drum 44 is engaged with the second guiding groove 64 on the main body side, and the drum casing is placed on the third guiding groove 65 on the main body side. With the drum side guide projection 53 engaged, the grip portion 36 is gripped and the photosensitive drum Rotary shaft 63 of the 44 until it hits the lower end of the main body side second guide groove 64 is slid downwardly.

  Then, the main body side first guide groove 62, the main body side second guide groove 64, and the main body side third guide groove 65 allow the developing side guide protrusion 37 of the developing casing 31, the rotating shaft 63 of the photosensitive drum 44, and the drum of the drum casing 43 to be used. The side guide protrusions 53 are respectively guided downward in the vertical direction. Further, when the drum casing 43 faces the scanner side guide portion 28 provided in the scanner casing 20, it is guided by the scanner side guide portion 28, and subsequently, the boss portion 61 of the cover portion 47 of the drum casing 43 is connected to the scanner casing 20. 2, the boss portion 61 is engaged with the locking groove 29 of the scanner side guide portion 28, whereby the boss portion 61 is guided to the locking groove 52 (FIG. 2). (Refer to (a) and (b)). Thereafter, the rotating shaft 63 of the photosensitive drum 44 comes into contact with the lower end portion of the second guide groove 64 on the main body side, and the photosensitive drum 44 is attached to the main casing 2 as a unit so that the photosensitive drum 44 faces and contacts the conveying belt 56. .

  When the developing unit 18 and the photosensitive drum unit 19 are mounted on the main body casing 2 in this way, the rotating shaft 63 of the photosensitive drum 44 is connected to the lower end of the main body-side second guide groove 64 as shown in FIG. Before elastically contacting a pressing spring 68 (shown only in FIGS. 6 and 9) as a buffer member provided at the lower end of the main body side second guide groove 64 in the main body casing 2 just before hitting the portion, The pressure spring 68 is overcome. In the state where the rotation shaft 63 of the photosensitive drum 44 is in contact with the lower end portion of the main body side second guide groove 64, the pressing spring 68 presses the rotation shaft 63 downward. The photosensitive drum 44 can be positioned so as to contact.

Further, in the main casing 2, a pressing lever 69 (shown only in FIG. 6) is formed on the lower part of the developing casing 31 so as to protrude on both sides in the width direction (shown only in FIG. 6). Is provided so as to be pressed downward.
The pressing lever 69 is moved to a retracted position indicated by a virtual line and a pressing position indicated by a solid line by driving a motor (not shown). When the photosensitive drum 44 rotates, the photosensitive drum 44 is moved to the pressing position, and when the photosensitive drum 44 stops rotating, the photosensitive drum 44 is moved to the retracted position. Thereby, the developing roller 34 can be positioned so as to be surely brought into contact with the photosensitive drum 44. The pressing lever 69 may be interlocked with the opening / closing of the top cover 7 instead of the motor.

  When the photosensitive drum unit 19 and the developing unit 18 are integrally detached from the main casing 2, first, as shown in FIG. 5, the top cover 7 is first opened and then opened. From the upper opening of the main casing 2 formed by the top cover 7, the photosensitive drum unit 19 and the developing unit 18 that are attached to each other are gripped by the gripping portion 36 and slid upward.

  Then, the rotating shaft 63 of the photosensitive drum 44 moves over the pressing spring 68 against the pressing force of the pressing spring 68, and the boss portion 61 is moved vertically upward by the locking groove 29 of the scanner side guide portion 28. In addition, the main body side first guide groove 62, the main body side second guide groove 64, and the main body side third guide groove 65 lead to the development side guide protrusion 37 of the developing casing 31, the rotating shaft 63 of the photosensitive drum 44, and the drum casing. The drum-side guide projections 53 of 43 are respectively guided vertically upward, and the photosensitive drum unit 19 and the developing unit 18 that are attached to each other are pulled out from the main body casing 2 as a whole, whereby the photosensitive drum unit 19 and the developing unit 18 are pulled out. Are integrally detached from the main casing 2.

For example, referring to FIG. 5, the cyan process unit 14 </ b> C is referred to for attaching / detaching the developing unit 18 to / from the photosensitive drum unit 19 in a state where the photosensitive drum unit 19 is attached to the main casing 2.
When the developing unit 18 is detached from the photosensitive drum unit 19 with the photosensitive drum unit 19 attached to the main casing 2, as described above, the photosensitive drum unit 19 and the developing unit 18 that are attached to each other are attached to the main casing. As shown in FIG. 4 (a), the top cover 7 is first opened, and the upper opening of the main casing 2 formed by the opened top cover 7 is opened. Then, the operating portion 41 of the engaging lever 40 of the developing casing 31 is moved forward, and the engagement of the claw portion 42 with the locking groove 52 is released. Thereafter, the grip portion 36 is gripped, and the developing unit 18 is slid upward.

  Then, the mounting of the developing unit 18 to the photosensitive drum unit 19 is released, and the roller shaft 67 of the developing roller 34 is pulled out from the drum side guide groove 51 of the drum casing 43 as shown in FIG. Thus, the developing unit 18 is detached. Next, the developing side guide protrusion 37 of the developing casing 31 is guided vertically upward by the main body side first guide groove 62, and the developing unit 18 is pulled out from the main body casing 2. As a result, only the developing unit 18 is detached from the main casing 2.

  Further, when the developing unit 18 is attached to the photosensitive drum unit 19 with the photosensitive drum unit 19 still attached to the main casing 2, first, the top cover 7 is opened, and the top cover 7 that is opened. From the upper opening of the main body casing 2 formed by the above, the developing unit 18 is gripped by the gripping portion 36 with the main body side first guide groove 62 engaged with the developing side guide protrusion 37 of the developing casing 31. Slide down.

  Then, the developing-side guide protrusion 37 of the developing casing 31 is guided downward in the vertical direction by the main body-side first guide groove 62. When the developing side guide protrusion 37 is guided to the lower end portion of the main body side first guide groove 62, the roller shaft 67 of the developing roller 34 is at that position as shown in FIG. The drum side guide groove 51 is engaged. Next, the roller shaft 67 is guided to the drum side guide groove 51, whereby the guide of the developing casing 31 is transferred from the main body casing 2 to the drum casing 43.

  Thereafter, when the roller shaft 67 of the developing roller 34 is in a position before the lower end portion of the drum side guide groove 51, the claw portion 42 positioned forward by the spring contacts the upper end portion of each side plate 49 of the drum casing 43. Touch. Thereafter, as shown in FIG. 4A, the developing unit 18 is slid downward with the operating portion 41 moved forward and the claw portion 42 of the engaging lever 40 moved rearward, thereby developing roller. When the user releases his / her hand from the operation portion 41 at a position where the roller shaft 67 of the 34 is the lower end position of the drum side guide groove 51, the claw portion 42 is moved into the engagement groove 52 of the drum casing 43 by the biasing force of the spring. Is engaged. As a result, the developing unit 18 is attached to the photosensitive drum unit 19 so that the developing roller 34 faces the photosensitive drum 44.

  In the color laser printer 1 described above, since the process unit 16 and the scanner unit 17 are arranged alternately in the horizontal direction, the top cover 7 can be opened without moving the scanner unit 17. The developing unit 18 and the photosensitive drum unit 19 of the process unit 16 can be attached and detached from the upper opening of the main casing 2 formed by the above. In the state where each photosensitive drum unit 19 and each developing unit 18 are mounted on the main casing 2, the developing roller 34 is disposed above the photosensitive drum 44, and the supply roller 33 is disposed above the developing roller 34. A toner hopper 32 is disposed above the supply roller 33. Further, the photosensitive drum 44, the developing roller 34, the supply roller 33, and the toner hopper 32 are provided so as to overlap in the vertical direction, which is the attaching / detaching direction of the photosensitive drum unit 19 and the developing unit 18. Further, the photosensitive drum 44 and the scorotron charger 45 are disposed in the vertical projection surface of the toner hopper 32, and the roller portion of the developing roller 34 and the roller portion of the supply roller 33 are disposed in the vertical projection surface of the photosensitive drum 44. Is arranged.

  Therefore, the developing unit 18 and the photosensitive drum unit 19 of the process unit 16 can be smoothly attached to and detached from the main body casing 2 without the scanner unit 17 fixed to the main body casing 2 interfering. Therefore, since the scanner unit 17 is fixed to the main casing 2 without being moved when the process unit 16 is attached or detached, accurate exposure can be ensured.

Further, with the above arrangement in each process unit 16, each process unit 16 can be formed thin in the front-rear direction, and space saving in the horizontal installation area can be achieved.
In the color laser printer 1, the developing unit 18 and the photosensitive drum unit 19 can be integrally attached to and detached from the main body casing 2, and the photosensitive drum unit 19 can be attached to the main body casing 2 while being attached to the main body casing 2. The developing unit 18 can be attached to and detached from the photosensitive drum unit 19.

  Therefore, in toner empty, after the used developing unit 18 is detached from the photosensitive drum unit 19 with the photosensitive drum unit 19 attached to the main casing 2, the new developing unit 18 is attached to the photosensitive drum unit 19. It is possible to replace only the developing unit 18 with a high replacement frequency. As a result, the running cost can be reduced and the industrial waste can be reduced rather than replacing the photosensitive drum unit 19 and the developing unit 18 as a single unit. Furthermore, the replacement work of the developing unit 18 can be facilitated.

In the tandem type color laser printer 1 having the photosensitive drum 44 for each color, each color is sequentially transferred by each photosensitive drum 44. Therefore, each photosensitive drum 44 has a positioning accuracy in order to prevent color misregistration between the colors. Therefore, unnecessary attachment / detachment of each photosensitive drum 44 should be avoided.
However, if the developing unit 18 is replaced with the photosensitive drum unit 19 in a state where the photosensitive drum unit 19 is mounted on the main casing 2 in this way, only the developing unit 18 is removed without attaching or detaching the photosensitive drum 44. Can be exchanged. Therefore, it is possible to prevent the positional deviation of each photosensitive drum 44 and form a high-quality color image with little color deviation.

  When the photosensitive drum 44 is replaced, the developing unit 18 and the photosensitive drum unit 19 are detached from the main casing 2 as described above, and then the developing unit 18 is detached from the used photosensitive drum unit 19. Then, after the developing unit 18 is attached to a new photosensitive drum unit 19 and then attached to the main casing 2 as a unit, the photosensitive drum unit 19 having a low replacement frequency can be replaced.

  Further, in such an attaching / detaching operation, the developing side guide projection 37 of the developing casing 31 is guided in the vertical direction by the main body side first guide groove 62, so that the attaching / detaching operation of the developing unit 18 with respect to the main body casing 2 is ensured. be able to. Further, the main body side second guide groove 64 and the main body side third guide groove 65 guide the rotating shaft 63 of the photosensitive drum 44 and the drum side guide protrusion 53 of the drum casing 43 in the vertical direction, respectively. It is possible to ensure the attaching / detaching operation of the photosensitive drum unit 19 with respect to the sensor.

The main body side first guide groove 62, the main body side second guide groove 64, and the main body side third guide groove 65 are provided in parallel to the longitudinal direction of the surface of the scanner casing 31 of the scanner unit 17. The developing unit 18 alone or both the developing unit 18 and the photosensitive drum unit 19 can be attached and detached from between the scanner units 17.
Moreover, the main body side first guide groove 62, the main body side second guide groove 64, and the main body side third guide groove 65 are side plates 66 that face each other on both sides in the width direction of the developing unit 18 (both sides in the axial direction of the developing roller 34). In FIG. 4, the developing unit 18 and the photosensitive drum unit 19 can be guided to be attached to and detached from the main body casing 2 with a simple configuration.

  Further, since the development unit 18 is provided with two development side guide projections 37 along the vertical direction, the development side guide projections 37 are engaged with the first guide groove 62 on the main body side. The developing unit 18 can be guided in a state where shakiness in the direction is prevented. For this reason, even if the developing unit 18 is formed long in the vertical direction, it can be stably attached to and detached from the main casing 2.

  Further, in the photosensitive drum unit 19, the boss portion 61 of the cover portion 47 is guided by the locking groove 29 of the scanner side guide portion 28 provided in the scanner casing 20, so that the photosensitive drum unit 19 can be more stably attached and detached. Can do. In addition, the scanner-side guide portion 28 that guides the boss portion 61 is formed integrally with the scanner casing 20, that is, the surface of the scanner casing 20 also serves as a guide member for the developing unit 18. The photosensitive drum unit 19 can be attached and detached while reducing the above-mentioned and simplifying the apparatus configuration.

  In the color laser printer 1, when the developing unit 18 is attached to and detached from the photosensitive drum unit 19, the developing roller 34 is exposed to light by the roller shaft 67 of the developing roller 34 being guided by the drum-side guide groove 51 of the photosensitive drum unit 19. It is guided so as to face the drum 44. Therefore, the positional accuracy of the developing roller 34 with respect to the photosensitive drum 44 is good, and a good color image can be formed.

  Moreover, in this color laser printer 1, when the developing unit 18 is mounted on the photosensitive drum unit 19 with the photosensitive drum unit 19 still mounted on the main casing 2, the developing casing 31 is first the first on the main body side. Due to the engagement between the guide groove 62 and the development side guide projection 37, the roller shaft 67 of the developing roller 34 is guided to the guide start position guided by the drum side guide groove 51. Next, the main body side first guide groove 62 and the development side are developed. While the engagement with the side guide protrusion 37 is released, the roller shaft 67 and the drum side guide groove 51 are engaged, whereby the developing roller 34 is guided to a position where it contacts the photosensitive drum 44. As a result, even if the photosensitive drum unit 19 is mounted on the main casing 2, the developing roller 34 can be disposed with high positional accuracy with respect to the photosensitive drum 44.

  In the color laser printer 1, in the above-described attachment / detachment operation, the developing unit 18, which is provided on the developing unit 18 and protrudes upward from the scanner unit 17, holds the developing unit 18 alone or the developing unit 18 and Both of the photosensitive drum units 19 can be smoothly attached to and detached from the main casing 2. Therefore, operability can be improved. In particular, the upper end portion of the grip portion 36 is provided with a hook-like hook portion 36a extending rearward, so that the user opens the top cover 7 from the front side and extends his hand from the front side. The gripping part 36 can be gripped by hooking the hand on the hooking part 36a extending to the opposite side. Therefore, the grip part 36 can be firmly gripped.

  As in the color laser printer 1, when the scanner units 17 and the process units 16 are alternately arranged so as to overlap in the horizontal direction and the color laser printer 1 is downsized, the gap between the scanner unit 17 and the process unit 16 is reduced. However, if the gripping portion 36 is provided in this way, a space for gripping the process unit 16 can be formed, and the gripping portion 36 can be formed. It becomes possible to hold the process unit 16 easily.

  Further, in the color laser printer 1, the front wall, the rear wall, and both side walls of the developing casing 31 are arranged in the vertical direction in the state where each developing unit 18 is mounted on the main body casing 2. Accordingly, the toner contained in the toner hopper 32 and in contact with the front wall, the rear wall, and both side walls of the toner hopper 32 can be favorably moved in the direction of gravity. Therefore, the toner can be smoothly supplied from the toner hopper 32 to the supply roller 33 and further to the developing roller 34.

  In the present embodiment, the developing casing 31 is formed so that the front wall, the rear wall, and both side walls of the developing casing 31 are arranged in the vertical direction in a state where the developing unit 18 is mounted on the main casing 2. However, if these walls are not arranged so as to incline upward toward the outside of the toner hopper 32, for example, these walls are arranged so as to incline toward the inside of the toner hopper 32 upward. Thus, the developing casing 31 may be formed.

In each developing unit 18, the toner moving from the toner hopper 32 in the direction of gravity is satisfactorily stirred by the agitator 38 provided on the toner hopper 32 on the side close to the developing roller 34, and the supply roller 33, It can be supplied to the developing roller 34.
In this color laser printer 1, in each developing unit 18, the toner in the toner hopper 32 is supplied by its own weight to the supply roller 33 disposed below the gravitational direction. There is no need to provide the agitator 38. That is, the toner in the toner hopper 32 can be circulated and supplied to the supply roller 33 only by providing one agitator 38 on the side close to the developing roller 34.

  In the color laser printer 1, the process unit 16 to which the developing unit 18 and the photosensitive drum unit 19 are attached to each other is attached to the mounting surface 71 in a state where it is removed from the main casing 2 as shown in FIG. By bringing the first abutting portion 48a of the drum casing 43 into contact with each other, these are integrally placed in a vertically placed state (the state where the photosensitive drum 44 and the developing roller 34 are aligned in the vertical direction). be able to. In this state, the lower developing side guide projection 37 of the developing unit 18 is brought into contact with the upper end portion of the side plate 49 of the photosensitive drum unit 43.

  Further, as shown in FIG. 8, the process unit 16 to which the developing unit 18 and the photosensitive drum unit 19 are attached to each other has the drum casing 43 with respect to the mounting surface 71 in a state where it is removed from the main casing 2. By abutting the second abutting portion 48b and the second abutting portion 39 of the developing casing 31, the two abutting portions 48b and the second abutting portion 39 of the developing casing 31 are stabilized in a horizontally placed state (a state where the photosensitive drum 44 and the developing roller 34 are aligned in the horizontal direction). Can be placed.

  In other words, the process unit 16 of the color laser printer 1 selectively selects the first contact portion 48a or the second contact portions 39 and 48b with respect to the placement surface 71 in a state where it is removed from the main body casing 2. By abutting, it can be stably placed in either a vertically placed state or a horizontally placed state. Therefore, it is possible to prevent the process unit 16 from being overturned and to facilitate handling in either the vertically placed state or the horizontally placed state.

  Further, in this color laser printer 1, as shown in FIG. 9, the horizontal width of the main body side first guide groove 62 is slightly widened without developing the lower end portion of the main body side first guide groove 62, and development is performed. When the unit 18 is mounted on the main casing 2, the developing side guide protrusion 37 on the lower side of the developing unit 18 extends slightly below the facing position, and the lower developing side of the developing unit 18 is at the lower end thereof. You may provide the spring 72 as a buffer member which receives the guide protrusion 37. FIG.

  When such a spring 72 is provided, when the developing unit 18 (the developing unit 18 with the photosensitive drum unit 19 mounted) is mounted, as shown in FIG. 9A, the developing unit 18 faces downward. 9, even if the hand is mistakenly released from the gripping part 36 and the developing unit 18 falls due to its own weight, the spring 72 causes the lower part of the developing unit 18 to move under its own weight as shown in FIG. The developing side guide projection 37 on the side can be elastically received. Therefore, the collision between the developing roller 34 and the photosensitive drum 44 can be alleviated, and damage to them can be prevented.

  In FIG. 9, the above-described pressing spring 68 (see FIG. 6) is also provided at the lower end portion of the main body side second guide groove 64, so that the rotating shaft 63 of the photosensitive drum 44 is formed by the pressing spring 68. Can be elastically received. For this reason, the collision between the rotating shaft 63 of the photosensitive drum 44 and the photosensitive drum 44 and the transfer roller 57 can be mitigated, and damage to them can be prevented.

In the above description, the scorotron charger 45 is fixed to the rear wall of the drum accommodating portion 46 of the photosensitive drum unit 19, but is arranged so as to overlap the photosensitive drum 44 in the vertical direction as shown in FIG. 10. It may be provided so as to be movable between an attaching / detaching position and a mounting position arranged so as to overlap the photosensitive drum 44 in the horizontal direction.
That is, in FIG. 10, the rear wall of the drum housing portion 46 is opened, and a rotatable charging cover 73 for fixing the scorotron charger 45 is provided on the drum housing portion 46 whose rear wall is opened. ing.

  As shown in FIG. 11, the charging cover 73 has a U shape that is slightly wider than the drum housing portion 46, and one end of the charging cover 73 is relative to the rotating shaft 63 at both ends in the axial direction of the rotating shaft 63 of the photosensitive drum 44. A cover side plate 74 having a triangular plate shape in a side view and connected in a rotatable manner, and a rectangular plate-like support plate 75 laid between the other end portions of each cover side plate 74 are integrally formed. A scorotron charger 45 is fixed to the surface of the support plate 75 facing the photosensitive drum 44. As a result, the support plate 75 is placed in a state where the scorotron charger 45 is fixed, and the cover side plates 74 are spaced apart so that the scorotron charger 45 can face the photosensitive drum 44 with a predetermined gap. Through the rotation axis 63 of the photosensitive drum 44 so as to be rotatable.

Further, on each cover side plate 74, a guide pin 76 that can be engaged with the main body side second guide groove 64 of the main body casing 2 protrudes outward in the width direction at a position facing the scorotron charger 45. Is provided.
In addition, each cover side plate 74 is provided with a leg portion 77 that contacts the lower end portion of the drum accommodating portion 46 at the attachment / detachment position.

On the other hand, as shown in FIG. 10, the main body side second guide groove 64 provided in the main body casing 2 is formed such that the lower end thereof is curved toward the rear to the fixing position of the scorotron charger 45.
Thus, for example, when the process unit 16 is mounted, the process unit 16 is first placed in the attach / detach position so that the process unit 16 of the black process unit 14K in FIG. 10 is referred to. In the position where the unit 16 is attached to the main body casing 2 of the process unit 16, the guide pins 76 and the rotating shaft 63 of the photosensitive drum 44 are sequentially engaged with the second guide groove 64 on the main body side, Slide towards. Then, as the process unit 16 of the cyan process unit 14C is referred to, when the guide pin 76 reaches the curved portion at the lower end of the main body side second guide groove 64, the charging cover 73 is rotated by the guide of the guide pin 76. The shaft 63 is rotated backward (rotated clockwise) by approximately 90 °. When the mounting of the process unit 16 to the main body casing 2 is completed, the charging cover 73 faces in the horizontal direction so that the process unit 16 of the magenta process unit 14M and the yellow process unit 14Y is referred to, and the scorotron charger 45 is The photosensitive drum 44 is disposed at a mounting position that overlaps the photosensitive drum 44 in the horizontal direction.

  Further, when the process unit 16 is detached, the operation reverse to the above, that is, the process unit 16 is slid upward by the same method as described above. Then, the charging cover 73 is rotated about 90 ° downward (rotated counterclockwise) about the rotation shaft 63 by the guide of the guide pin 76. As a result, the scorotron charger 45 is disposed at the attachment / detachment position overlapping the photosensitive drum 44 in the vertical direction, so that the process unit 16 may be pulled out of the main casing 2 as it is.

  If the scorotron charger 45 is moved between the attachment / detachment position and the attachment position in this way, the scorotron charger 45 is disposed at the attachment / detachment position overlapping the photosensitive drum 44 in the vertical direction during attachment / detachment. The process unit 16 can be attached and detached without the scorotron charger 45 interfering with the scanner unit 17. On the other hand, at the time of mounting, the scorotron charger 45 is disposed at a mounting position that overlaps with the photosensitive drum 44 in the horizontal direction, so that the scorotron charger 45 is placed in the scanner unit 17 while the photosensitive drum 44 is disposed at the transfer position. Thus, the color laser printer 1 can be reduced in size in the horizontal direction.

  In addition, when the process unit 16 is detached from the main casing 2, the scorotron charger 45 is positioned at the attachment / detachment position. Therefore, as shown in FIG. 11, the charging cover 73 for fixing the scorotron charger 45 is provided. By bringing the support plate 75 into contact with the mounting surface 71 as it is, the process unit 16 can be mounted in a vertical state. That is, in the state where the scorotron charger 45 is located at the attachment / detachment position, the scorotron charger 45 can also serve as the first contact portion, so that the number of parts can be reduced and the device configuration can be simplified. Can do.

In this way, in the state where the process unit 16 is placed in a vertically placed state, the leg portion 77 of each cover side plate 74 is in contact with the lower end portion of the drum housing portion 46.
Further, the drum housing portion 46 is provided with a rotation stop spring 78 (shown only in FIG. 11) that urges toward one end portion of each cover side plate 74 that is connected to the rotation shaft 63 so as to be relatively rotatable. A receiving groove 79 (shown only in FIG. 11) for receiving the rotation stop spring 78 is formed at one end of each cover side plate 74. In the state where the process unit 16 is placed vertically, the rotation stop spring 78 is received by the receiving groove 79, so that the rotation of each cover side plate 74 around the rotation shaft 63 is restricted. .

Therefore, the process unit 16 is controlled by the contact of the leg 77 with the lower end of the drum housing portion 46 and the rotation restriction of each cover side plate 74 by the fitting of the rotation stop spring 78 and the receiving groove 79. It can be stably placed in a vertically placed state.
In the above description, the image forming apparatus of the present invention has been described as a so-called horizontal type tandem color laser printer 1, but the image forming apparatus of the present invention includes four image forming apparatuses as shown in FIG. The process unit 14 may be configured as a so-called vertical tandem type color laser printer 1 arranged in parallel in the vertical direction.

Note that the color laser printer 1 shown in FIG. 12 is basically the same as the above-described horizontal type except for the arrangement. Therefore, the same reference numerals are given to the same members, and the description thereof is omitted.
In FIG. 12, the color laser printer 1 includes a front cover 81 provided on the front side of the main casing 2 instead of the top cover 7. The front cover 81 is disposed on the opposite side of the photosensitive drum 44 from the transfer position in contact with the conveying belt 56 of the transfer unit 15, and is rotatably supported via a hinge 7 a provided on the front side of the main body casing 2. As indicated by a virtual line, the main casing 2 is provided so as to be openable and closable.

Further, a paper feed unit 4 is provided at the bottom of the main body casing 2, and a paper discharge unit 6 (however, the paper discharge roller 8 is not provided) is provided at the top of the main body casing 2. Further, the image forming unit 5 includes the process unit 14, the transfer unit 15, and the fixing unit 60 in the same manner as described above.
In the process unit 14, a yellow process unit 14Y, a magenta process unit 14M, a cyan process unit 14C, and a black process unit 14K are sequentially arranged in parallel in the vertical direction at a predetermined interval from the lower side to the upper side. ing. The process unit 14 includes a scanner unit 17 and a process unit 16, which are alternately arranged so as to overlap in the vertical direction.

  The scanner unit 17 is fixed to the main casing 2, and the process unit 16 can be attached to and detached from the main casing 2 in the horizontal direction integrally with the developing unit 18 and the photosensitive drum unit 19 as described above. In a state where the drum unit 19 is mounted on the main casing 2, the developing unit 18 is configured to be detachable from the photosensitive drum unit 19 in the horizontal direction. Although not shown in FIG. 12, the color laser printer 1 shown in FIG. 12 is also provided with a guide member for attaching and detaching the developing unit 18 and the photosensitive drum unit 19.

  In each process unit 16, a developing roller 34 is disposed in front of the photosensitive drum 44, a supply roller 33 is disposed in front of the developing roller 34, and a toner hopper 32 is disposed in front of the supply roller 33. In addition, the photosensitive drum 44, the developing roller 34, the supply roller 33, and the toner hopper 32 are provided so as to overlap in the horizontal direction, which is the attaching / detaching direction of the photosensitive drum unit 19 and the developing unit 18. Further, the photosensitive drum 44 and the scorotron charger 45 are disposed in the horizontal projection surface of the toner hopper 32, and the developing roller 34 and the supply roller 33 are disposed in the horizontal projection surface of the photosensitive drum 44.

The toner hopper 32 of the developing unit 18 is provided with two agitators 38 spaced apart from each other in the horizontal direction.
Further, the transfer unit 15 is provided to face each photosensitive drum 44 on the opposite side of each developing drum 18 in each photosensitive drum 44 arranged in the vertical direction.
The fixing unit 60 is provided above the transfer unit 15.

  Also in the vertical type color laser printer 1 shown in FIG. 12, the process unit 16 and the scanner unit 17 are alternately arranged in the vertical direction, so that the front cover can be moved without moving the scanner unit 17. The developing unit 18 and the photosensitive drum unit 19 of the process unit 16 can be detached from the front opening of the main casing 2 formed by opening 81. In the state where each photosensitive drum unit 19 and each developing unit 18 are mounted on the main casing 2, the developing roller 34 is disposed in front of the photosensitive drum 44, and the supply roller 33 is disposed in front of the developing roller 34. A toner hopper 32 is disposed in front of the supply roller 33. In addition, the photosensitive drum 44, the developing roller 34, the supply roller 33, and the toner hopper 32 are provided so as to overlap in the horizontal direction, which is the attaching / detaching direction of the photosensitive drum unit 19 and the developing unit 18. Further, the photosensitive drum 44 and the scorotron charger 45 are disposed in the horizontal projection surface of the toner hopper 32, and the roller portion of the developing roller 34 and the roller portion of the supply roller 33 are disposed in the horizontal projection surface of the photosensitive drum 44. Is arranged.

  Therefore, the developing unit 18 and the photosensitive drum unit 19 of the process unit 16 can be smoothly attached to and detached from the main body casing 2 without the scanner unit 17 fixed to the main body casing 2 interfering. Therefore, since the scanner unit 17 is fixed to the main casing 2 without being moved when the process unit 16 is attached or detached, accurate exposure can be ensured.

Further, with the above arrangement in each process unit 16, each process unit 16 can be formed thin in the vertical direction, and the apparatus in the vertical direction can be downsized.
In the above description, the scanner unit 17 configured as a laser scanner is provided as the exposure unit. However, for example, an LED array may be provided instead of the scanner unit 17.

In the above description, the development unit 18 is configured to be detachable with respect to the photosensitive drum unit 19 in the process unit 16, but the photosensitive drum unit 19 and the development unit 18 are integrally configured without being detachable. Also good.
Further, in the above description, the direct transfer type tandem color laser printer 1 that directly transfers from each photosensitive drum 44 to the paper 3 is exemplified, but the image forming apparatus of the present invention is not limited to this. Alternatively, for example, a toner image of each color may be temporarily transferred from each photoconductor to an intermediate transfer member, and then transferred to a sheet at once, and may be configured as an intermediate transfer type tandem color laser printer.

1 is a side cross-sectional view of a main part showing an embodiment (horizontal installation type) of a color laser printer as an image forming apparatus of the present invention. FIG. 2 is an enlarged cross-sectional side view of a main part of a process unit of the color laser printer shown in FIG. (B) shows a state in which the developing unit is detached from the photosensitive drum unit in a state where the photosensitive drum unit is mounted on the main body casing. 1A and 1B show a photosensitive drum unit of the color laser printer shown in FIG. 1. FIG. 1A is a front sectional view of an essential part, and FIG. FIG. 2 is a side view of a main part showing a process unit of the color laser printer shown in FIG. 1, where (a) shows a state in which a developing unit is attached to the photosensitive drum unit, and (b) shows development with respect to the photosensitive drum unit. Indicates that the unit is detached. FIG. 2 is a side cross-sectional view of a main part of the color laser printer shown in FIG. 1, in which a photosensitive drum unit and a developing unit are attached to and detached from a main body casing. FIG. 6 is an enlarged cross-sectional side view of a main part of the color laser printer shown in FIG. 5 with a photosensitive drum unit and a developing unit being attached to and detached from a main body casing. It is a principal part side view which shows the state in which the process unit of the color laser printer shown in FIG. 1 is mounted in the mounting surface in the vertical state. It is a principal part side view which shows the state by which the process unit of the color laser printer shown in FIG. 1 is mounted in the horizontal state in the mounting surface. In the color laser printer shown in FIG. 1, the main part side first guide groove is provided with a spring 72 at the lower end thereof, and is a cross-sectional side view of a main part, wherein (a) shows the developing unit facing downward. (B) shows a state where the lower developing side guide protrusion is elastically received by the spring. FIG. 2 is a cross-sectional side view of a main part of an embodiment in which the scorotron charger is configured to be movable between an attachment / detachment position and a mounting position in the color laser printer shown in FIG. It is a principal part side view which shows the state by which the process unit of the color laser printer shown in FIG. 10 is mounted in the mounting surface in the vertical state. FIG. 6 is a cross-sectional side view of a main part showing another embodiment (vertical installation type) of a color laser printer as an image forming apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color laser printer 2 Main body casing 3 Paper 7 Top cover 16 Process unit 17 Scanner unit 18 Developing unit 19 Photosensitive drum unit 20 Scanner casing 32 Toner hopper 32a Filling port 33 Supply roller 34 Developing roller 36 Holding part 36a Hook part 37 Developing side guide protrusion 38 Agitator 39 Second contact portion 41 Operation portion 42 Claw portion 44 Photosensitive drum 45 Scorotron charger 48a First contact portion 48b Second contact portion 51 Drum-side guide groove 52 Locking groove 53 Drum-side guide protrusion 62 Main body side First guide groove 63 Rotating shaft 64 Main body side second guide groove 65 Main body side third guide groove 67 Roller shaft 68 Pressing spring 72 Spring

Claims (27)

A developer accommodating chamber for accommodating a developer, a developer carrying member for carrying the developer, and a developer image formed by developing an electrostatic latent image with the developer carried on the developer carrying member. A process unit that is detachably attached to the image forming apparatus main body, and is fixed to the image forming apparatus main body, and a laser beam is used to form an electrostatic latent image on the image carrier. An exposure unit that scans the image bearing member for each color of the developer of a plurality of colors,
The process units and the exposure means are alternately arranged,
An opening / closing member that opens and closes with respect to the image forming apparatus main body on the opposite side of the transfer position to which the developer image carried on the image carrier is transferred in the image carrier;
The process unit is provided so as to be attached to and detached from the image forming apparatus main body from an opening formed by opening the opening / closing member, and in a state where the process unit is detached from the image forming apparatus main body, It can be placed in either a vertically placed state in which the developer carrier is aligned in the vertical direction or a horizontally placed state in which the image carrier and the developer carrier are horizontally arranged. A first contact portion that contacts the placement surface in the vertically placed state, and a second contact portion that contacts the placement surface in the horizontally placed state ,
The process unit includes a developing unit having the developer storage chamber and the developer carrier, and an image carrier having the image carrier.
The developing unit and the image carrying unit are detachable integrally with the image forming apparatus main body, and the developing unit is provided detachably with respect to the image carrying unit,
The image forming apparatus according to claim 1, wherein the first contact portion is provided in the image carrying portion, and the second contact portion is provided in each of the image carrying portion and the developing portion . A developer accommodating chamber for accommodating a developer, a developer carrying member for carrying the developer, and a developer image formed by developing an electrostatic latent image with the developer carried on the developer carrying member. A plurality of process units having an image carrier that can be attached to and detached from the main body of the image forming apparatus, and exposure means that are fixed to the main body of the image forming apparatus and that form an electrostatic latent image on the image carrier. For each color of developer,
An opening / closing member that opens and closes with respect to the image forming apparatus main body on the opposite side of the transfer position to which the developer image carried on the image carrier is transferred in the image carrier;
The process unit is provided so as to be attached to and detached from the image forming apparatus main body from an opening formed by opening the opening / closing member, and in a state where the process unit is detached from the image forming apparatus main body, It can be placed in either a vertically placed state in which the developer carrier is aligned in the vertical direction or a horizontally placed state in which the image carrier and the developer carrier are horizontally arranged. A first contact portion that contacts the placement surface in the vertically placed state, and a second contact portion that contacts the placement surface in the horizontally placed state,
The image carrier, the developer carrier, and the developer storage chamber are provided so as to overlap in the attaching / detaching direction of the process unit ,
The process unit includes a developing unit having the developer storage chamber and the developer carrier, and an image carrier having the image carrier.
The developing unit and the image carrying unit are detachable integrally with the image forming apparatus main body, and the developing unit is provided detachably with respect to the image carrying unit,
The image forming apparatus according to claim 1, wherein the first contact portion is provided in the image carrying portion, and the second contact portion is provided in each of the image carrying portion and the developing portion . The process unit is provided with a supply means for supplying the developer stored in the developer storage chamber to the developer carrier.
3. The image according to claim 2, wherein the supply unit is provided so as to overlap the image carrier, the developer carrier, and the developer storage chamber in the attaching / detaching direction of the process unit. Forming equipment.   4. The image forming apparatus according to claim 2, wherein the image carrier and the developer carrier are arranged in a projection plane in the attachment / detachment direction of the process unit in the developer storage chamber. 5. .   5. The image forming apparatus according to claim 3, wherein the supply unit is disposed in a projection surface of the developer storage chamber in the attaching / detaching direction of the process unit.   In a state where the process unit is mounted on the image forming apparatus main body, the developer carrier is disposed above the image carrier, and the developer storage chamber is disposed above the developer carrier. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   The image forming apparatus according to claim 3, wherein the supply unit is provided between the developer carrier and the developer storage chamber. The developing unit is characterized in that detachably attached to the image bearing unit mounted to the image forming apparatus main body, an image forming apparatus according to any one of claims 1 to 7. 9. The apparatus according to claim 1, further comprising: an engaging portion provided in the image carrying portion; and an engaged portion provided in the developing portion so as to be engageable with the engaging portion . The image forming apparatus according to any one of the above. The image forming apparatus according to claim 9 , further comprising an operation unit that is provided in the developing unit and releases the engagement between the engaging unit and the engaged unit. A first guide portion provided in the image carrying portion, for guiding the developing portion so that the developer carrying body faces the image carrier, and provided in the developing portion; characterized in that it includes a first guided portion to be guided, the image forming apparatus according to any one of claims 1 to 1 0. Provided in the image forming apparatus main body, characterized in that it comprises a second guide portion for guiding the attachment and detachment of the developing unit to the image forming apparatus main body, an image forming apparatus according to claim 1 1. The second guide unit is configured so that the first guided unit of the developing unit is guided to the guidance start position of the first guide unit of the image carrying unit mounted on the image forming apparatus main body. characterized by guiding the second guided portion, the image forming apparatus according to claim 1 2. Provided in the image forming apparatus main body, characterized in that it comprises a third guide portion for guiding the attachment and detachment of the image bearing unit relative to the image forming apparatus main body, an image according to claim 1 2 or 1 3 Forming equipment. Said second guide portion and the third guide unit is characterized in that provided substantially parallel to the housing surface of the exposure unit, the image forming apparatus according to claim 1 4. Housing surface of the exposure means, characterized in that it also serves as a guide member of the image bearing unit, the image forming apparatus according to claim 1 4 or 1 5. Said second guide portion and the third guide portion, and the developing unit, and being provided so as to face in the axial direction on both sides of the developer carrier, according to claim 1 4 and 1 6 The image forming apparatus according to any one of the above. At least one of the deepest part of the second guide part and the deepest part of the third guide part is provided with a buffer member that receives the second guided part of the developing part or the guided part of the image bearing part. wherein the image forming apparatus according to any one of claims 1 4 to 1 7. The wall in the developer accommodating portion along the attaching / detaching direction of the process unit is disposed in a substantially vertical direction in a state where the process unit is mounted on the image forming apparatus main body, or the developing unit faces upward. agent, characterized in that it is arranged to be inclined inwardly of the housing unit, the image forming apparatus according to any one of claims 6 to 1 8. Provided on a side closer to the developer carrier in the developer chamber, characterized in that it comprises a stirring member for stirring the developer, an image forming according to any one of claims 6 to 19 apparatus. Wherein provided in the process unit, characterized in that it comprises a grip portion for gripping the process unit, the image forming apparatus according to any one of claims 1 to 2 0. An operation panel to be operated by the user, the gripper is characterized in that it comprises a hook portion extending on the opposite side of the operation panel side, the image forming apparatus according to claim 2 1. The process unit is disposed to face the image carrier, and includes a charging unit for charging the image carrier.
The charging unit is mounted so as to overlap in an attachment / detachment position where the image carrier and the process unit are attached in an attachment / detachment direction, and overlapped in a direction intersecting the attachment / detachment direction of the image carrier and the process unit. and the position, characterized in that it is movable, the image forming apparatus according to any one of claims 1 to 2 2. It said charging means is the detaching position, characterized in that serves as the first contact portion, the image forming apparatus according to claim 2 3. One of the walls arranged on both sides in the longitudinal direction of the developer carrier in the developer accommodating portion is provided with a filling port for filling the developer on the side far from the developer carrier. wherein the image forming apparatus according to any one of claims 1 to 2 4. 3. The developer remaining on the image carrier after the developer image carried on the image carrier is transferred to a transfer medium is collected by the developer carrier. the image forming apparatus according to any one of 5. Developer, characterized in that it is a toner having a substantially spherical image forming apparatus according to any one of claims 1 to 2 6.

Images