JP3868369B2 - Image forming apparatus and process cartridge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus in which a process cartridge is detachably provided to a main body of an image forming apparatus such as a copying machine, a facsimile machine, and a printer, and a process cartridge provided in the image forming apparatus.
[0002]
[Prior art]
Conventionally, there is a process cartridge as a cartridge configured to be detachable from the image forming apparatus. The process cartridge integrally constitutes an image forming station including a developing member including a developer carrier and a photoconductor as an image carrier. The process cartridge is mounted on the image forming apparatus main body so that the photosensitive member included in the cartridge is in contact with the transfer member inside the main body in the image forming apparatus main body.
[0003]
In recent years, with the widespread use of personal computers, color printers and color copying machines have been demanded, and their high speed has been demanded. For this reason, so-called tandem color printers in which a plurality of photoconductors are arranged in parallel are increasing. In addition, due to the trend of space saving, not only large tandem color printers but also small desktop machines are increasing. Some of these tandem type color printers have a process cartridge mounted detachably. When the process cartridge is mounted, the photosensitive member included in the cartridge is in contact with an intermediate transfer belt as an intermediate transfer member in the apparatus main body, a transfer roller as a transfer member, or the like via the intermediate transfer belt.
In this tandem color printer, an image forming station including a photoconductor is provided for each color. For this reason, maintenance is frequently required as compared with a monochrome printer having a single image forming station. Therefore, there is a strong demand for improving maintenance so that the user can easily perform maintenance. Then, when replacing each member of the image forming station when the life of the member is reached or damaged, an operation of attaching / detaching the process cartridge to / from the apparatus main body is required.
Conventionally, when a process cartridge is attached to or detached from the image forming apparatus main body, the cartridge is moved in the thrust direction with respect to the surface of a member in contact with a photosensitive member on an intermediate transfer belt or the like in the apparatus main body.
[0004]
[Problems to be solved by the invention]
However, if the process cartridge is attached to or detached from the image forming apparatus main body while the photoconductor is in contact with the intermediate transfer belt or the like, the surface of the intermediate transfer belt or the like and the surface of the photoconductor are rubbed against each other. Become. This is not preferable because the deterioration of the photosensitive member, the intermediate transfer belt, and the like is accelerated.
Also, in order to attach or detach the process cartridge without accelerating the deterioration of the photoconductor or the intermediate transfer belt, the cartridge transfer operation is performed after the intermediate transfer belt has been moved to a position separated from all the photoconductors in advance. is there. However, in this method, two operations, that is, an operation for separating the intermediate transfer belt from the photosensitive member and a process cartridge attaching / detaching operation must be performed in a predetermined procedure. For this reason, the operation procedure for attaching and detaching the cartridge becomes complicated, and it becomes somewhat difficult for the user to perform it. For this reason, conventionally, maintenance that requires attachment and detachment of the process cartridge has been generally performed by a service person.
[0005]
Therefore, in a tandem type color printer, it is required that the process cartridge can be easily attached and detached without accelerating the deterioration of the photosensitive member, the intermediate transfer belt, and the like.
[0006]
It should be noted that the requirement to easily attach and detach the process cartridge without accelerating the deterioration of the photosensitive member or the like is not limited to a tandem type color printer, but may occur in an image forming apparatus having a process cartridge. If the image forming apparatus has the process cartridge mounted in the mounting so that the photosensitive member comes into contact with any member in the main body of the image forming apparatus, the above-mentioned request is generated to some extent.
[0007]
The present invention has been made in view of the above background, and its object is to provide the following. A first object is to provide an image forming apparatus having a process cartridge that can be easily attached and detached from the apparatus main body without accelerating the deterioration of the image carrier and the member that contacts the image carrier. A second object of the present invention is to provide a process cartridge that can be easily attached and detached from the image forming apparatus main body without accelerating the deterioration of the image carrier or the member that contacts the image carrier.
[0008]
[Means for Solving the Problems]
  In order to achieve the first object, the invention of claim 1 includes a roller-shaped image carrier, a latent image forming unit for forming a latent image on the image carrier, and a development for developing the latent image. An image forming apparatus having a process cartridge in which at least the image carrier and the developing unit are integrally supported and detachable from the apparatus main body along the roller axis direction of the image carrier. The image carrier is attached to the process cartridge.ofA movable support member for supporting the image carrier so as to move relative to the housing is provided, and the image carrier in the process cartridge is inserted into the image forming apparatus body as the process cartridge is inserted into the image forming apparatus body. A guide member that engages with a portion of the body roller shaft in the insertion direction and that is disengaged from the process cartridge when the process cartridge is extracted from the apparatus main body; During the insertion and extraction operations, the image carrier is located at a retracted position where no other member contacts the surface, and the image carrier performs an image forming operation as the insertion of the process cartridge into the apparatus main body is completed. The portion of the process cartridge in which the guide member is engaged with the guide member so as to be positioned at a predetermined position of the process cart It is characterized in that the induction with the insertion and withdrawal operation for Tsu apparatus main body of di.
  According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the movable support member moves the image carrier between the retracted position and the predetermined position. And the surface of the developer carrier provided in the developing means, while maintaining a constant distance between the image carrier and the process cartridge.ofThe image carrier is supported so as to move relative to the housing.
  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the movable support member is configured so that the image carrier can swing around a rotation axis of the developer carrier. It is characterized by supporting the body.
  According to a fourth aspect of the present invention, in the image forming apparatus according to the first, second, or third aspect, the process cartridge includes the image carrier before the latent image forming unit forms a latent image on the image carrier. The charging means for charging the upper part is integrally supported together with the image carrier and the developing means, and the movable support member is configured such that the charging means and the image carrier are combined with the process cartridge.ofThe charging unit and the image carrier are supported so as to move relative to the housing.
  According to a fifth aspect of the present invention, in the image forming apparatus according to the first, second, third or fourth aspect, the process cartridge is inserted into and removed from the apparatus main body.HousingIs configured so as not to be displaced in a direction perpendicular to the attaching / detaching direction.
  According to a sixth aspect of the present invention, in the image forming apparatus of the first, second, third, fourth, or fifth aspect, the volume average particle diameter Dv [μm] and the number average particle diameter Dn [μm] of the toner used in the developing means are used. (Dv / Dn) is 1.05 or more and 1.30 or less.
  The invention according to claim 7 is the image forming apparatus according to claim 1, wherein the toner image formed on the image carrier is primarily transferred onto the intermediate transfer member. And a secondary transfer means for secondary transfer of the primary transfer toner image on the intermediate transfer member onto the transfer material.
  The invention according to claim 8 is the image forming apparatus according to claim 7, wherein the image forming apparatus has a plurality of image carriers facing the intermediate transfer member, and toner images of different colors formed on the respective image carriers are displayed on the image forming device. A superposed toner image is formed on the intermediate transfer member by sequentially superimposing the intermediate transfer member on the intermediate transfer member to perform primary transfer, and the superposed toner image is collectively transferred onto the transfer material. Is.
  In order to achieve the second object, the invention of claim 9 is a process cartridge in which the image carrier and the developing means are integrally supported.A movable support member is provided for supporting the image carrier so that the image carrier moves relative to the housing of the process cartridge. During the insertion and extraction operation of the process cartridge with respect to the apparatus main body, the image carrier is positioned at a retracted position where no other members come into contact with the surface of the process cartridge. By engaging a portion on the front end side in the insertion direction of the image carrier roller shaft in the process cartridge with a guide member provided in the image forming apparatus main body so as to be positioned at a predetermined position for performing an image forming operation. The process cartridge is guided in accordance with insertion and extraction operations with respect to the apparatus main body.It is characterized by this.
  In the image forming apparatus according to any one of claims 1 to 8, as the process cartridge is inserted into the main body of the image forming apparatus, the front side (back side) of the cartridge in the insertion direction of the image carrier roller shaft (hereinafter referred to as appropriate). (Referred to as “predetermined part”) engages with the guide member. Then, along with the insertion operation, the guide member guides a predetermined part and positions the image carrier at the retracted position. As a result, during the insertion operation, the image carrier can be positioned at the retracted position. Here, the retracted position is a position where there is no member in contact with the surface of the image carrier. Further, as the member that contacts the surface of the image carrier, various members including a transfer material or an intermediate transfer body that is a target for transferring the toner image on the surface of the image carrier can be considered. When the process cartridge is inserted to the far side and the guiding of the predetermined portion of the cartridge by the guide member is completed, the image carrier is positioned at the predetermined portion. The predetermined position is a position for the image carrier to perform an image forming operation. On the other hand, when the process cartridge is detached from the apparatus main body, the cartridge with the image carrier in a predetermined position is extracted from the apparatus main body. Along with this extraction operation, the guide member guides a predetermined part and positions the image carrier in the retracted position. Thus, the image carrier can be positioned at the retracted position even during the extraction operation.
  As described above, during the insertion / extraction operation with respect to the apparatus main body for attaching / detaching the process cartridge, the image carrier is in the retracted position without performing any other operation. Further, by inserting the cartridge into the apparatus main body to the end, the image carrier can be positioned at a predetermined position without performing other operations. Therefore, as in the conventional process cartridge attaching / detaching operation, when the image carrier is in a predetermined position, it is not necessary to previously separate the member disposed in contact with the surface of the image carrier from the surface of the image carrier. Absent.
  As described above, in the present invention, the attachment / detachment operation of the process cartridge with respect to the apparatus main body can be performed by an easy operation of only the insertion and extraction operations without bringing the surface of the image carrier into contact with other members. As a result, both the ease of the process cartridge attaching / detaching operation and the prevention of the deterioration due to the process cartridge attaching / detaching operation of the image carrier and the members arranged in contact with the image carrier during the image forming operation can be realized. be able to.
  The process cartridge according to claim 9 is a cartridge that can be easily attached to and detached from the image forming apparatus main body and can prevent the image carrier from being deteriorated due to the process cartridge attaching and detaching operation.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electrophotographic printer (hereinafter simply referred to as a printer) will be described as an example of an embodiment of an image forming apparatus to which the present invention is applied.
FIG. 1 is a schematic configuration diagram of a printer according to the present embodiment.
First, the configuration and operation of the printer will be described. As shown in FIG. 1, the printer has four sets of image forming means for forming images of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) in the frame body. Image stations 1Y, 1C, 1M, and 1Bk are provided. Since the image stations 1Y, 1C, 1M, and 1Bk have the same configuration, the image station 1Y will be described.
[0010]
FIG. 2 is a schematic configuration diagram of the image station. As shown in FIGS. 1 and 2, in the image station 1Y, the photosensitive drum 2 as a latent image carrier is uniformly charged by a charging roller 3 as a charging device. Thereafter, the optical writing unit 4 performs scanning exposure with laser light based on the image information to form an electrostatic latent image on the surface of the photoreceptor 2. The electrostatic latent image formed on the photoreceptor 2 is developed with yellow toner carried on the developing roller 51Y of the developing device 5Y, and visualized as a toner image. In this way, in the image station 1Y, a yellow toner image is formed on the photoreceptor 2Y. Similarly, toner images of the respective colors are formed on the photosensitive drums 2C, 2M, and 2Bk at the other image stations 1C, 1M, and 1Bk. The toner image formed on the photosensitive member 2 is transferred onto the intermediate transfer belt 6 as an intermediate transfer member that is rotationally driven counterclockwise for each primary color of yellow, cyan, magenta, and black as a primary transfer unit. The images are sequentially superimposed and transferred by the bias rollers 7Y, 7C, 7M, and 7Bk. The superimposed toner images of yellow, cyan, magenta, and black superimposed on the intermediate transfer belt 6 are fed from the sheet feeding cassette 9 through the sheet feeding roller 9a by the secondary transfer bias roller 8 as a secondary transfer unit. The transferred image is transferred to the transfer paper. After the transfer, the transfer paper is fixed with a toner image by the fixing device 10 and is discharged out of the apparatus as a full-color printer. As described above, this printer is a tandem color printer.
[0011]
As shown in FIG. 3, the above-described photoreceptor 2Y, charging unit 3Y, developing device 5Y, and photoreceptor cleaning device 12Y described later are integrally supported as a process cartridge 18Y that can be attached to and detached from the frame of the apparatus body. ing. The process cartridge attaching / detaching mechanism will be described in detail later.
[0012]
In addition, toner bottles 11Y, 11C, 11M, and 11Bk that store toner of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) are loaded on the upper portion of the printer body. The toner filled in the toner bottle 11 is supplied to the developing device 5 as necessary. The toner bottles 11Y, 11C, 11M, and 11Bk are configured to be removable by opening the apparatus cover. When the amount of toner in the toner bottle 11 falls below a predetermined amount, the user replaces it with another toner bottle that is newly filled with toner.
[0013]
Here, the untransferred toner on the photoreceptors 2Y, 2C, 2M, and 2Bk that has not been transferred to the intermediate transfer belt 6 is collected by the photoreceptor cleaning devices 12Y, 12C, 12M, and 12Bk. The photoconductor cleaning devices 12Y, 12C, 12M, and 12Bk remove the transfer residual toner on the photoconductors 2Y, 2C, 2M, and 2Bk by the cleaning blade 13 and the cleaning brush 14. Further, the transfer residual toner on the intermediate transfer belt 6 that has not been transferred onto the transfer paper 9 is collected by the intermediate transfer belt cleaning device 15.
[0014]
In the tandem color printer having the above configuration, when the process cartridge is mounted at a predetermined position inside the apparatus main body, the photosensitive members 2Y, 2C, 2M, and 2Bk are in contact with the intermediate transfer belt, and the intermediate transfer belt is Via the primary transfer roller. For this reason, when the process cartridge is attached or detached for maintenance, the process cartridge is extracted or inserted while the photoreceptors 2Y, 2C, 2M, and 2Bk are in contact with the intermediate transfer belt or the like. This is not preferable because the deterioration of the photoreceptors 2Y, 2C, 2M, 2Bk, the intermediate transfer belt, and the like is accelerated. In order to avoid this, there has been conventionally proposed a method of attaching and detaching the process cartridge after the intermediate transfer belt is moved to a position separated from all the photoreceptors 2Y, 2C, 2M, and 2Bk. However, such an operation is somewhat difficult for the user to perform, and has been assisted by a service person. It is also desirable for service personnel to be able to perform a simpler attachment / detachment method.
[0015]
  Therefore, in this embodiment, the process cartridges 18Y, 18C, 18M, and 18Bk can be easily attached and detached without causing damage to the photoreceptors 2Y, 2C, 2M, and 2Bk. This feature will be described below.
  The internal structure of the process cartridge will be described using the process cartridge 18Y shown in FIG. However, the same applies to the other process cartridges 18C, 18M, and 18Bk. In FIG. 3, the process cartridge 18Y includes a developing device 5Y, a photoconductor 2Y, a charging roller 3Y, and a photoconductor cleaning device 12Y inside the housing. The developing device 5Y includes a developing roller 51Y, a developer stirring screw 52Y, and a developer regulating blade 53Y. FIG. 4 is an explanatory diagram of the structure of the support portion of the photosensitive member 2Y, the charging roller, and the developing roller, and FIG. 5 is a plan view of the process cartridge 18Y as viewed from above. Each rotating shaft of the photoreceptor 2Y, the charging roller, and the developing rollerIsRespectively,The photosensitive member rotating shaft is 2Ya, the charging roller rotating shaft is 3Ya, and the developing roller rotating shaft is 51Ya. The photosensitive member rotating shaft 2Ya, the charging roller rotating shaft 3Ya, and the developing roller rotating shaft 51Ya are connected and supported by an L-shaped support member (hereinafter referred to as a support arm) 21Y as a movable support member so as to be able to rotate. Yes. Further, as shown in FIG. 3, the support arm 21Y is provided so as to be swingable about the developing roller shaft. Each rotating shaft is supported by the support arm 21Y at both ends in the axial direction of the three rollers of the photoconductor 2Y, the charging roller, and the developing roller. As a result, the photosensitive member 2Y and the charging roller can be rotated around the developing roller shaft, and the relative positional relationship between these three members can always be kept constant. Therefore, as shown in FIG. 5, the development gap (Gp), which is the distance between the photoreceptor 2Y and the development roller, can be maintained with high accuracy.
[0016]
On the other hand, the internal structure of the printer main body will be described. When the process cartridge 18Y is mounted on the printer body, the front cover on the front side of the apparatus is opened, and the process cartridge 18Y is inserted in the photosensitive member axial direction. At this time, a guide member 30 is provided on the back side of the printer main body at the position where the process cartridge 18Y is mounted to pick up the shaft of the photoreceptor 2Y and guide it to a predetermined position where image formation is possible.
6A is a front view of the guide member 30, and FIG. 6B is a cross-sectional view of the XY cross section of FIG. 6A viewed from the right direction (the arrow direction in FIG. 6A). These show how the photosensitive member shaft 2Ya is moved by the guide member 30. As shown in FIG. 6, the guide member 30 is provided with a guide groove 30a that is wide at the bottom and narrow at the top. Further, the back side wall surface 30b in the process groove insertion direction in the guide groove is constituted by a wall surface 30b that is inclined from the front to the back in the insertion direction from the lower side to the upper side of the guide groove.
[0017]
  In the above configuration, when the process cartridge 18Y is mounted, the process cartridge 18Y is first inserted into the printer main body in the direction of the photosensitive member axis. At this time, the positions of the photosensitive member 2Y and the charging roller within the process cartridge are naturally positioned below by gravity at the position indicated by the solid line in FIG. 3, and this is a retracted position described later. When the process cartridge 18Y continues to be inserted into the printer body to some extent, the tip of the photoreceptor shaft 2Ya reaches a position where the guide member 30 is provided. At this time, the front end of the photoconductor shaft enters the lower side of the guide groove 30a, that is, the position A1 in FIG. 6A, and strikes the wall surface 30b on the back side of the guide groove as shown in FIG. 2YaButIt will be in the state engaged with the guide member. When the cartridge is further inserted, the front end of the photoreceptor shaft slides with the inclination of the wall surface 30b in accordance with the insertion operation, and a force that pushes the photoreceptor 2Y upward is applied. Under the influence of this force, the photosensitive member 2Y and the charging roller rotate upward about the developing roller shaft inside the process cartridge. On the way, it passes the position of A2 and continues to rise. When the guide groove finally rises to the top of the guide groove, the end of the photosensitive member shaft enters the positioning hole 30c formed in the wall surface 30b, and the process cartridge 18Y cannot be inserted any more and the insertion operation ends. The position A3 in FIG. 6A is a predetermined position for the photoreceptor 2Y to perform the image forming operation, and the process cartridge mounting is completed. Further, when the photosensitive member 2Y until reaching the position of A3 is positioned below A3, the photosensitive member 2Y is in a retracted position where it is not in contact with the intermediate transfer belt.
[0018]
In the printer of the present embodiment, the process cartridge 18 can be attached / detached at the same time with the four process cartridges 18Y, 18C, 18M, and 18Bk. FIG. 7 is a diagram illustrating a state in which the process cartridge is mounted on the printer main body. FIG. 8 is a diagram illustrating a state when the process cartridge 18 integrally configured with the four process cartridges 18Y, 18C, 18M, and 18Bk is extracted from the printer main body. When the process cartridge 18 is extracted from the state shown in FIG. 7, the front cover 40 on the front surface of the apparatus is opened. Then, the four process cartridges 18 are extracted together. When the process cartridge 18 starts to be extracted, along with this extraction operation, the guide member guides the front end of the photosensitive member shaft to place the photosensitive member in the retracted position. When further extracted, the engagement with the guide groove at the end of each photosensitive member shaft is released. As a result, as shown in FIG. 8, all four process cartridges 18Y, 18C, 18M, and 18Bk are extracted from the opening on the front surface of the apparatus. Conversely, when the process cartridge 18 is inserted in the back and stopped at a position where it cannot be pushed any further, the front cover 40 is closed.
[0019]
In the above, the method of attaching and detaching the four process cartridges 18Y, 18C, 18M, and 18Bk integrally has been described. However, the process cartridges 18Y, 18C, 18M, and 18Bk may be configured to be detachable individually for each color.
In the above embodiment, the end of the photosensitive member shaft passes through the guide groove of the guide member both when the process cartridge 18 is mounted and when it is detached. That is, the passage path at the tip of the photosensitive member shaft by the attaching / detaching operation is the same. In place of this, it is also possible to perform a pull-out operation at the time of detachment, and the photosensitive body shaft tip can be removed from the guide groove and dropped by its own weight. Even with this configuration, the photoreceptors 2Y, 2C, 2M, and 2Bk can be positioned at the retracted position during the extraction operation when the process cartridge 18 is detached from the printer main body.
[0020]
When the process cartridges 18Y, 18C, 18M, and 18Bk are attached and detached as described above, the following effects can be obtained. The relative movement of the process cartridges 18Y, 18C, 18M, and 18Bk with respect to the printer main body for attaching / detaching the process cartridge can be performed without performing any special operation other than insertion or extraction. Therefore, the attaching / detaching operation can be performed without bringing the intermediate transfer belt or the like into contact with the surface of the photoreceptor. Further, when the process cartridges 18Y, 18C, 18M, and 18Bk are mounted on the printer main body, the photoreceptors 2Y, 2C, 2M, and 2Bk are positioned at predetermined positions in synchronization with the operation of inserting the cartridge into the printer main body being stopped. For this reason, it is not necessary to perform a special operation for moving the positions of the photoconductors 2Y, 2C, 2M, and 2Bk to a predetermined position immediately after mounting the process cartridge. As a result, the process cartridge mounting / removal operation can be easily performed only by inserting / removing operation, and can be performed without causing deterioration of the photoconductors 2Y, 2C, 2M, 2Bk, the intermediate transfer belt, and the like, thereby improving maintenance. Can be made.
[0021]
Next, the developer will be described. The developing device of the printer according to the present embodiment uses a two-component developer containing toner and a magnetic carrier. Hereinafter, the toner and the magnetic carrier will be described.
<Toner particle size>
The volume average particle diameter (Dv) of the toner is 4 to 8 [μm], and the ratio (Dv / Dn) of the volume average particle diameter Dv [μm] to the number average particle diameter Dn [μm] is 1. 05 or more and 1.30 or less are preferable. More preferably, the volume average particle diameter Dv / number average particle diameter Dn is 1.10 or more and 1.25 or less. By using the toner having such a particle size, the particle size distribution of the toner becomes narrow, and the following effects can be obtained.
1. Since a phenomenon such as selective development in terms of toner particle diameter hardly occurs, a stable image can always be formed. Here, the selective development refers to a phenomenon in which toner particles having a (suitable) toner particle size corresponding to an image pattern are selectively developed.
2. When the toner recycling system is installed, small-sized toner particles that are difficult to be transferred are recycled in a large quantity. However, since the toner particle size distribution is originally narrow, it is difficult to receive the above-described action. Therefore, a stable image can always be formed from this point.
3. In the two-component developer, even if the toner balance for a long time is performed, the fluctuation of the toner particle diameter in the developer is reduced, and good and stable developability can be obtained even in the long-term stirring in the developing device.
4). Even when used as a one-component developer, even if the balance of the toner is performed, the fluctuation of the toner particle diameter is reduced, and the toner filming on the developer carrying member and the toner thinning are performed. The toner does not adhere to a member such as a blade. Therefore, good and stable developability and images can be obtained even in the long-term use (stirring) of the developing device.
[0022]
In general, it is said that the smaller the particle size of the toner, the more advantageous it is to obtain a high-resolution and high-quality image, but it is disadvantageous for transferability and cleaning properties. is there. Further, when the volume average particle diameter Dv of the toner is smaller than the above range (4 to 8 [μm]), in the two-component developer, the toner is fused to the surface of the magnetic carrier during long-term stirring in the developing device, and the magnetic carrier This will reduce the charging ability. Also, when used as a one-component developer, toner filming on the developer carrier and toner fusion to a member such as a blade for thinning the toner are likely to occur. Further, these phenomena are the same for the toner having a fine powder content higher than the range of the present embodiment. On the other hand, when the volume average particle diameter Dv of the toner is larger than the above range (4 to 8 [μm]), it becomes difficult to obtain a high-resolution and high-quality image, and the toner in the developer In many cases, when the balance is made, the variation in the particle diameter of the toner becomes large. It was also clarified that the same applies when the value of the volume average particle diameter Dv / number average particle diameter Dn is larger than 1.30. Further, when the value of the volume average particle diameter Dv / number average particle diameter Dn is smaller than 1.05, there are preferable aspects from the viewpoint of stabilizing the behavior of the toner and equalizing the charge amount. However, in this case, it is difficult to separate the functions according to the toner particle diameter, such as developing the fine line portion with small size particles and developing the solid image mainly with large size particles.
[0023]
<Measurement method of toner particle size>
The toner particle size can be measured using, for example, a toner particle size distribution measuring device by a Coulter counter method. Examples of the measuring device include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). Hereinafter, a method for measuring the toner particle diameter using this measuring apparatus will be described. First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is prepared by preparing an about 1% NaCl aqueous solution using primary sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the volume and number of toner particles or toner are measured using the 100 [μm] aperture as the aperture. Then, the volume distribution and the number distribution are calculated. From the obtained distribution, the volume average particle diameter (Dv) and the number average particle diameter (Dn) of the toner can be obtained. As channels, 2.00 to less than 2.52 [μm]; 2.52 to less than 3.17 [μm]; 3.17 to less than 4.00 [μm]; 4.00 to 5.04 [μm] Less than 5.04 to 6.35 [μm]; 6.35 to less than 8.00 [μm]; 8.00 to less than 10.08 [μm]; 10.08 to less than 12.70 [μm]; 12.70 to less than 16.00 [μm]; 16.00 to less than 20.20 [μm]; 20.20 to less than 25.40 [μm]; 25.40 to less than 32.00 [μm]; Using 13 channels of 00 to less than 40.30 [μm], particles having a particle size of 2.00 [μm] or more to less than 40.30 [μm] were targeted.
[0024]
In the embodiment described above, an example in which the present invention is applied to a tandem type color printer has been described, but an apparatus to which the present invention can be applied is not limited thereto. The printer is applicable to any printer having a process cartridge in which at least the photosensitive members 2Y, 2C, 2M, and 2Bk and the developing device are integrally supported and can be detached from the printer main body. Further, the printer using the two-component developer composed of toner and magnetic carrier as the developer has been described. However, the present invention can be applied to a printer using a developing device that performs development using toner that is a one-component developer. it can.
[0025]
In this embodiment, the movement of the photosensitive member between the retracted position and the predetermined position during the process cartridge attaching / detaching operation is performed by moving the photosensitive member relative to the cartridge housing within the process cartridge. Is going. Therefore, the cartridge housing, the developing roller and the like that are not likely to come into contact with the intermediate transfer belt when the process cartridge is attached / detached are not particularly moved to the retracted position. Therefore, it is not necessary to move an extra member together with the photosensitive member.
Further, in order to improve maintenance as described above, support arms 218Y, 21C, 21M, and 21Bk provided in the process cartridge and a guide member 30 provided in the printer main body are used. This facilitates a configuration for improving maintenance.
In this embodiment, the ratio (Dv / Dn) of the volume average particle diameter Dv [μm] of the developer toner to the number average particle diameter Dn [μm] is preferably 1.05 or more and 1.30 or less. By using the toner having such a particle size, the particle size distribution of the toner becomes narrow, and the following effects can be obtained.
1. Since a phenomenon such as selective development in terms of toner particle diameter hardly occurs, a stable image can always be formed.
2. When the toner recycling system is installed, small-sized toner particles that are difficult to be transferred are recycled in a large quantity. However, since the toner particle size distribution is originally narrow, it is difficult to receive the above-described action. Therefore, a stable image can always be formed from this point.
3. In the two-component developer, even if the toner balance for a long time is performed, the fluctuation of the toner particle diameter in the developer is reduced, and good and stable developability can be obtained even in the long-term stirring in the developing device.
4). Even when used as a one-component developer, even if the balance of the toner is performed, the fluctuation of the toner particle diameter is reduced, and the toner filming on the developer carrier and the toner thinning are performed. The toner does not adhere to a member such as a blade. Therefore, good and stable developability and images can be obtained even in the long-term use (stirring) of the developing device.
[0026]
The printer of this embodiment is an intermediate transfer type printer using an intermediate transfer belt. Since the present invention is applied to such an apparatus, the intermediate transfer belt deteriorates due to the friction between the intermediate transfer belt and the photoreceptors 2Y, 2C, 2M, and 2Bk during the process cartridge attaching / detaching operation. Can also be prevented.
The printer of this embodiment is a tandem type color printer that is becoming popular due to the demand for higher speeds in recent years. Since the present invention is applied to an apparatus that particularly requires such high speed, there is a great merit due to the fact that maintenance can be improved.
In addition, the process cartridges 18Y, 18C, 18M, and 18Bk attached to the printer of the present embodiment are easily attached to and detached from the printer body, and the photoreceptors 2Y, 2C, 2M, and 2Bk are deteriorated due to the attachment / detachment operation. Since it does not occur, it is highly useful.
[0027]
【The invention's effect】
  Claims 1 to8Image forming apparatus and claim9According to the process cartridge of the present invention, both the ease of the process cartridge attaching / detaching operation and the prevention of the deterioration due to the process cartridge attaching / detaching operation of the image carrier and the member disposed in contact with the image carrier during the image forming operation are performed. Can be realized. Claims9According to this process cartridge, it is possible to realize both the ease of the process cartridge attaching / detaching operation and the prevention of deterioration due to the process cartridge attaching / detaching operation of the image carrier. Therefore, there is an excellent effect that the process cartridge can be easily attached to and detached from the image forming apparatus main body without accelerating the deterioration of the image carrier and the member that contacts the image carrier. As a result, the maintenance operation of the apparatus by the user can be facilitated, and maintenance can be improved.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a main part of a printer according to an embodiment.
FIG. 2 is a schematic configuration diagram of an image station of the printer according to the embodiment.
FIG. 3 is an explanatory diagram of a process cartridge according to the embodiment.
FIG. 4 is an explanatory diagram of a structure of a support portion for a photoconductor, a charging roller, and a developing roller.
FIG. 5 is a plan view of a process cartridge as viewed from above.
FIG. 6A is a front view of a guide member.
(B) is sectional drawing which looked at the XY cross section of (a) from the right direction.
FIG. 7 is a diagram illustrating a state where a process cartridge is mounted on a printer main body.
FIG. 8 is a diagram illustrating a state when a process cartridge is extracted from a printer main body.
[Explanation of symbols]
1Y, 1C, 1M, 1Bk image station
2Y, 2C, 2M, 2Bk photoconductor
2Ya photoconductor shaft
5Y, 5C, 5M, 5Bk development device
6 Intermediate transfer belt
7Y, 7C, 7M, 7Bk Primary transfer bias roller
12Y, 12C, 12M, 12Bk photoconductor cleaning device
14 Toner conveying means
15 Intermediate transfer belt cleaning device
18, 18Y, 18C, 18M, 18Bk Process cartridge
21Y support arm
30 Guide member
30a Guide groove
51Y, 51C, 51M, 51Bk Developing roller

Claims (9)

A roller-shaped image carrier; a latent image forming unit that forms a latent image on the image carrier; and a developing unit that develops the latent image. At least the image carrier and the developing unit are integrated. In an image forming apparatus having a process cartridge that is supported by the apparatus and is detachable from the apparatus main body along the roller axis direction of the image carrier,
The process cartridge is provided with a movable support member that supports the image carrier so that the image carrier moves relative to the housing of the process cartridge.
As the process cartridge is inserted into the image forming apparatus main body, the image forming apparatus main body engages with a portion of the process cartridge on the front side in the insertion direction of the image carrier roller shaft, and the process cartridge A guide member is provided that is disengaged from the device body as it is extracted from the main body,
During the process of inserting and extracting the process cartridge from the apparatus main body, the image carrier is located at a retracted position where no other member comes into contact with the surface of the process cartridge. The guide member guides the part of the process cartridge engaged with the guide member as the process cartridge is inserted into and extracted from the apparatus main body so that the guide member is positioned at a predetermined position for performing an image forming operation. An image forming apparatus. The image forming apparatus according to claim 1.
The movable support member moves the image carrier between the retracted position and the predetermined position, and keeps the distance between the surface of the image carrier and the surface of the developer carrier provided in the developing means constant. An image forming apparatus that supports the image carrier so as to move the image carrier relative to the housing of the process cartridge while maintaining the temperature of the image carrier. The image forming apparatus according to claim 2.
The image forming apparatus, wherein the movable support member supports the image carrier so that the image carrier can swing about a rotation axis of the developer carrier. The image forming apparatus according to claim 1, 2 or 3.
The process cartridge integrally supports, together with the image carrier and the developing unit, a charging unit that charges the image carrier before the latent image forming unit forms a latent image on the image carrier. And
The image forming apparatus, wherein the movable support member supports the charging unit and the image carrier so that the charging unit and the image carrier move together relative to the housing of the process cartridge. The image forming apparatus according to claim 1, 2, 3, or 4.
An image forming apparatus, wherein the housing of the process cartridge is configured not to be displaced in a direction perpendicular to the attaching / detaching direction during the operation of inserting and extracting the process cartridge from the apparatus main body. The image forming apparatus according to claim 1, 2, 3, 4 or 5.
The ratio of the volume average particle diameter Dv [μm] to the number average particle diameter Dn [μm] (Dv / Dn) of the toner used in the developing unit is 1.05 to 1.30. apparatus. The image forming apparatus according to claim 1, 2, 3, 4, 5 or 6.
A primary transfer unit that primarily transfers a toner image formed on the image carrier onto an intermediate transfer member; and a secondary transfer unit that secondary-transfers the primary transfer toner image on the intermediate transfer member onto a transfer material. An image forming apparatus. The image forming apparatus according to claim 7.
The intermediate transfer member has a plurality of image carriers opposite to the intermediate transfer member, and sequentially superimposes toner images of different colors formed on the respective image carriers on the intermediate transfer member to perform primary transfer. An image forming apparatus comprising: forming a superimposed toner image on the upper surface; and collectively transferring the superimposed toner image onto a transfer material. In the process cartridge in which the image carrier and the developing means are integrally supported,
A movable support member for supporting the image carrier so that the image carrier moves relative to the housing of the process cartridge;
During the process of inserting and extracting the process cartridge from the apparatus main body, the image carrier is located at a retracted position where no other member comes into contact with the surface of the process cartridge. Is engaged with a guide member provided on the main body of the image forming apparatus so that the image bearing roller shaft in the insertion direction of the image carrier roller shaft in the process cartridge is positioned at a predetermined position for performing an image forming operation. A process cartridge configured to be guided in accordance with insertion and extraction operations of the process cartridge with respect to the apparatus main body .

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