JP7166811B2 - image forming device - Google Patents

Description

The present invention relates to an electrophotographic image forming apparatus such as a laser printer and a copying machine.

An electrophotographic image forming apparatus generally includes a drum-shaped photoreceptor (hereinafter referred to as a photoreceptor drum) as an image carrier and a process for forming a toner image corresponding to an image on the photoreceptor drum. have the means. Conventionally, such an image forming apparatus employs a process cartridge system in which a photosensitive drum and a process means for forming a toner image are integrated into a cartridge and detachable from the image forming apparatus. there is

Generally, in an image forming apparatus adopting the process cartridge system, a preparatory operation for forming an image is executed when a new process cartridge (hereinafter simply referred to as cartridge) is installed in the image forming apparatus. The preparatory operation includes, for example, an operation of removing a sealing member (sealing member) provided in the developing means for the purpose of preventing toner leakage. In Patent Document 1, when a new cartridge is inserted into the main body of the image forming apparatus, a seal member provided in developing means is removed by a rotating member that rotates by receiving a driving force from a driving source that drives the cartridge. A stripping arrangement is disclosed.

In recent years, color images have been produced using an intermediate transfer system in which toner images are sequentially transferred from photosensitive drums of each color to an intermediate transfer body, and then the toner images are collectively transferred from the intermediate transfer body to a transfer material such as paper or an OHP sheet. The forming apparatus also adopts the process cartridge system. Japanese Unexamined Patent Application Publication No. 2002-100000 discloses a configuration of an intermediate transfer type image forming apparatus in which a drive source for driving some members of a cartridge and a drive source for driving an intermediate transfer body are shared.

Here, in the intermediate transfer type image forming apparatus, it is necessary to remove toner remaining on the intermediate transfer body after the toner image is secondarily transferred from the intermediate transfer body to the transfer material (hereinafter referred to as transfer residual toner). As a cleaning method for removing the transfer residual toner, a so-called blade cleaning method is widely used in which the transfer residual toner is scraped off by a cleaning blade as a contact member that contacts the intermediate transfer belt and collected in a cleaning container.

JP 2016-184143 A JP 2015-22189 A

In the configuration disclosed in Japanese Patent Application Laid-Open No. 2002-200000, when the cartridge sharing the drive source with the intermediate transfer member is replaced, the intermediate transfer member is also rotationally driven as the preparatory operation of the cartridge is performed. At this time, until the preparatory operation is completed, the intermediate transfer body continues to rotate in a state in which lubricant such as toner is not supplied to the position where the intermediate transfer body and the cleaning blade abut. Then, a large frictional force is generated at the position where the intermediate transfer member and the cleaning blade contact each other, and as a result, the tip of the cleaning blade may be deformed.

Accordingly, the present invention provides an image forming apparatus in which a drive source for driving some members of a cartridge and a drive source for driving an intermediate transfer body are shared, and the tip of the contact member that contacts the intermediate transfer body is The purpose is to suppress deformation.

The present invention comprises an apparatus main body, a first cartridge having a first developing means for forming a toner image on a first image carrier, and a toner image of a color different from that of the first image carrier. a second cartridge having a second developing means for forming a toner image on a second image carrier; and an intermediate contactable with the first image carrier and the second image carrier. a transfer member; a contact member that contacts the intermediate transfer member to form a contact portion and collects toner remaining on the intermediate transfer member;
a first driving source for rotationally driving the intermediate transfer member; a second driving source different from the first driving source, the second driving source for transmitting a driving force to the second cartridge; 1 driving source rotates the intermediate transfer member, and the second driving source transmits the driving force to the second cartridge, thereby transferring the image from the second developing means through the second image bearing member to the and a controller for controlling a supply operation for supplying toner to a contact portion, wherein the first cartridge is attachable to and detachable from the apparatus main body, wherein the controller comprises: wherein, when a new first cartridge is inserted into the apparatus main body, the supply operation is performed while the second image bearing member is in contact with the intermediate transfer member. and

According to the present invention, in an image forming apparatus in which a drive source for driving a part of the members of the cartridge and a drive source for driving the intermediate transfer body are shared, the leading edge of the contact member that contacts the intermediate transfer body is Deformation can be suppressed.

1 is a schematic cross-sectional view for explaining the configuration of an image forming apparatus according to Embodiment 1; FIG. FIG. 2 is a schematic diagram for explaining the configuration of a belt cleaning unit in Example 1; FIG. 2 is a schematic diagram illustrating a driving configuration in Example 1; FIG. 2 is a schematic diagram illustrating the configuration of a cartridge in Example 1; 7 is a flow chart for explaining a preparatory operation that is executed when a new cartridge is installed in the first embodiment; 4 is a flowchart for explaining each preparatory operation in the first embodiment; 4 is a timing chart illustrating the time required for each step during the first preparatory operation in Example 1. FIG. 9 is a flowchart for explaining preparatory operations in Comparative Example 1; 5 is a graph illustrating the relationship between the elapsed time and the driving torque of the intermediate transfer body when the intermediate transfer body is idly rotated in Example 1; and FIG. 11 is a schematic cross-sectional view for explaining the configuration of an image forming apparatus of a modified example. FIG. 10 is a schematic diagram for explaining a driving configuration in Example 2;

Preferred embodiments of the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of components described in the following examples should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. Accordingly, it is not intended to limit the scope of the invention unless specifically stated.

(Example 1)
[Configuration of Image Forming Apparatus]
FIG. 1 is a schematic cross-sectional view showing a schematic configuration of an image forming apparatus 100 according to this embodiment. The image forming apparatus 100 of this embodiment is a tandem-type laser beam printer that employs an intermediate transfer method capable of forming a full-color image using an electrophotographic method.

The image forming apparatus 100 has four image forming units a, b, c, and d arranged in a line. , black (Bk).

The image forming portion a includes a drum-shaped (cylindrical) photosensitive member (hereinafter referred to as a photosensitive drum 1a) as an image carrier, a charging roller 2a as charging means, and a drum cleaning means for collecting toner remaining on the photosensitive drum 1a. 3a, and developing means 4a. In the image forming apparatus 100 of the present embodiment, each means 1a to 4a constitutes an integrated process cartridge 9a (hereinafter referred to as cartridge 9a), which is detachable from the main body of the image forming apparatus 100. .

The developing means 4a includes a developing roller 41a as a developer bearing member, a developing container 42a containing non-magnetic one-component toner as a developer, a supply roller 43a for supplying toner to the developing roller 41a, and a developer regulating means. and a developing blade 44a as. The exposure means 12a shown in FIG. 1 is composed of a scanner unit that scans laser light with a polygonal mirror, and irradiates the photosensitive drum 1a with a scanning beam modulated based on an image signal, thereby exposing the photosensitive drum 1a to an electrostatic latent image. form an image.

In the following description, the configurations and operations of the image forming units a to d are substantially the same except that the colors of toners used are different. Therefore, hereinafter, the elements will be generally described by omitting the suffixes a, b, c, and d indicating that they are elements for one of the colors unless they are particularly distinguished.

At a position facing the image forming units a to d, an intermediate belt composed of an endless belt serving as a movable intermediate transfer member that can contact all of the photosensitive drums 1a, 1b, 1c, and 1d. A transfer belt 13 is arranged. The intermediate transfer belt 13 is stretched by three rollers, a secondary transfer counter roller 24 (hereinafter simply referred to as the counter roller 24 ), a drive roller 14 and a tension roller 15 . By rotating the drive roller 14, the intermediate transfer belt 13 moves (rotates) in the belt conveying direction indicated by the arrow R2 in the figure. The width direction of the intermediate transfer belt 13 is the direction orthogonal to the moving direction of the intermediate transfer belt 13 indicated by the arrow R2 in the drawing, and is the depth direction in FIG.

A primary transfer roller 10 as a primary transfer member is arranged at a position facing the photosensitive drum 1 with the intermediate transfer belt 13 interposed therebetween. The primary transfer roller 10 is urged with a predetermined pressure against the photosensitive drum 1 via the intermediate transfer belt 13, and a primary transfer portion (primary transfer nip) N1 where the intermediate transfer belt 13 and the photosensitive drum 1 are in contact with each other. forming By canceling the urging state of the primary transfer roller 10 against the photosensitive drum 1, the intermediate transfer belt 13 and the photosensitive drum 1 can be separated to eliminate the primary transfer portion N1. In the image forming apparatus 100 of this embodiment, the intermediate transfer belt 13 and the photosensitive drum 1 are separated from each other by canceling the biasing state of the primary transfer roller 10 during non-image formation.

Further, the image forming apparatus 100 of this embodiment has a full-color mode in which image formation is performed using all of the image forming units a to d, and only an image forming unit capable of forming a black (Bk) toner image. It is possible to select and execute a mono-color mode in which an image is formed using When executing the full-color mode, all of the photosensitive drums 1a, 1b, 1c, and 1d are brought into contact with the intermediate transfer belt 13 by urging all the primary transfer rollers 10 toward the photosensitive drums 1. FIG. On the other hand, when executing the monochrome mode, the urging forces of the primary transfer rollers 10a, 10b, and 10c are released, and only the primary transfer roller 10d is urged toward the photosensitive drum 1d. That is, when the mono-color mode is executed, only the photosensitive drum 1d carrying a black toner image is brought into contact with the intermediate transfer belt 13 to form an image.

A secondary transfer roller 25 as a secondary transfer member is arranged at a position facing the opposing roller 24 on the outer peripheral surface side of the intermediate transfer belt 13 . The secondary transfer roller 25 is urged with a predetermined pressure against the opposing roller 24 via the intermediate transfer belt 13, and the secondary transfer portion (second transfer portion) where the intermediate transfer belt 13 and the secondary transfer roller 25 are in contact A second transfer nip) N2 is formed.

In this embodiment, the primary transfer rollers 10a to 10d are constructed by covering a nickel-plated steel rod with an outer diameter of ⁵ mm with a foamed elastic material so as to have an outer diameter of 14 mm. of resistance was used. In order to perform good image formation in the configuration of the image forming apparatus 100 of this embodiment, it is desirable that the resistance of the primary transfer roller 10 is set in the range of 10 ³ to 10 ⁷ Ω.

Further, in this embodiment, the secondary transfer roller 25 is configured by covering a nickel-plated steel bar core with an outer diameter of ⁸ mm with a foam elastic body so as to have an outer diameter of 16 mm. A material having resistance was used. In order to perform good image formation in the configuration of the image forming apparatus 100 of this embodiment, the resistance of the secondary transfer roller 25 is preferably set within the range of 10 ⁷ to 10 ⁹ Ω.

The driving roller 14 used was an aluminum core bar coated with silicone rubber having a resistance of 10 ⁵ Ω and a thickness of 0.085 mm, in which carbon was dispersed as a conductive agent, and had an outer diameter of 26.3 mm. The tension roller 15 uses an aluminum metal rod with an outer diameter of 24 mm, and imparts a total tension of 98 N to the intermediate transfer belt 13 by applying 49 N to each end of one side. The opposing roller 24 positioned opposite the secondary transfer roller 25 was an aluminum cored bar with a resistance of 10 ⁵ Ω in which carbon was dispersed as a conductive agent and coated with EPDM rubber having a thickness of 1.0 mm and an outer diameter of 18 mm. .

The intermediate transfer belt 13 is made of a polyimide base material having a thickness of 73 μm and a volume resistivity of 10 ¹⁰ Ω·cm. The volume resistivity of the intermediate transfer belt 13 in this example was measured using a Hiresta UP MCP-HT450 (manufactured by Mitsubishi Chemical Corporation) under an environment of room temperature of 25° C. and humidity of 50% at an applied voltage of 50 V. , 10 ¹⁰ Ω·cm. In order to perform good image formation in the configuration of the image forming apparatus 100 of this embodiment, the volume resistivity of the intermediate transfer belt 13 should be set in the range of 10 ⁹ to 10 ¹² Ω·cm. preferable.

[Image forming operation]
A control board 101 shown in FIG. 1 is a control board on which an electric circuit for controlling the image forming apparatus 100 is mounted, and a CPU 102 as a control means is mounted. The control board 101 can perform preprogrammed operations by receiving signals transmitted from a host device (not shown) or the like, and image forming operations are executed by the CPU 102 controlling various means. be done. The CPU 102 in this embodiment controls the drive source for conveying the transfer material P, the intermediate transfer belt 13, the drive source for the cartridges 9a to 9d, and the like, the image formation control, and the failure detection control. It controls all operations collectively.

When the image forming operation is started, the photosensitive drums 1 and the intermediate transfer belt 13 start rotating in directions indicated by arrows R1 and R2 in the drawing at predetermined process speeds. The surface of the rotating photosensitive drum 1 is substantially uniformly charged to a predetermined polarity (negative polarity in this embodiment) by the charging roller 2 . At this time, a predetermined charging voltage is applied to the charging roller 2 from a charging power source (not shown). After that, the photosensitive drum 1 is exposed by the exposure means 12 according to the image information corresponding to each image forming section, thereby forming an electrostatic latent image on the surface of the photosensitive drum 1 according to the image information.

The developing roller 41 carries the toner supplied by the supply roller 43 and charged to the regular charging polarity (negative polarity in this embodiment) by the developer coating blade 42, and develops (not shown). A predetermined developing voltage is applied from the power supply. As a result, the latent image formed on the photosensitive drum 1 is visualized by the negative toner in the opposing portion (developing portion) between the photosensitive drum 1 and the developing roller 41 , and a toner image is formed on the photosensitive drum 1 .

Next, the toner image formed on the photosensitive drum 1 is transferred (primarily transferred) onto the intermediate transfer belt 13 which is driven to rotate by the action of the primary transfer roller 10 at the primary transfer portion N1. At this time, a primary transfer voltage having a polarity opposite to the normal charging polarity of the toner (positive polarity in this embodiment) is applied to the primary transfer roller 10 from the primary transfer power supply 22 . For example, when forming a full-color image, an electrostatic latent image is formed on each photosensitive drum 1 in each image forming station S, and this is developed into a toner image of each color. Then, the toner images of respective colors formed on the respective photosensitive drums 1 of the respective image forming units S are transferred onto the intermediate transfer belt 13 at the respective primary transfer units N1a, N1b, N1c and N1d so as to be superimposed one on the other. Four-color toner images are formed on the belt 13 .

A transfer material P such as recording paper stacked in a paper feed cassette 50 as a storage unit is transported to a registration roller 51 by a supply roller (not shown) and a transport roller (not shown). The transfer material P is synchronized with the toner image on the intermediate transfer belt 13 by the registration roller 51 and is conveyed to the secondary transfer portion N2 formed by the intermediate transfer belt 13 and the secondary transfer roller 25 . Then, the four-color multiple toner images carried on the intermediate transfer belt 13 are collectively transferred onto the transfer material P by the action of the secondary transfer roller 25 at the secondary transfer portion N2. At this time, a secondary transfer voltage having a polarity (in this embodiment, a positive polarity) opposite to the normal charging polarity of the toner is applied to the secondary transfer roller 25 from the secondary transfer power supply 26 .

Thereafter, the transfer material P onto which the toner image has been transferred is conveyed to fixing means 19 . The toner image that has been secondarily transferred onto the transfer material P is fixed onto the transfer material P by being pressed and heated in the process of being sandwiched between the fixing roller and pressure roller of the fixing means 19 and conveyed. The sheet is discharged to the outside of the image forming apparatus 100 by the sheet discharging roller pair 52 .

Toner remaining on the photosensitive drum 1 after the primary transfer is removed from the surface of the photosensitive drum 1 by a cleaning blade 31 provided in the drum cleaning means 3 and brought into contact with the photosensitive drum 1 . In addition, residual toner remaining on the intermediate transfer belt 13 after passing through the secondary transfer portion N2 is removed by belt cleaning means 20 provided facing the tension roller 15 with the intermediate transfer belt 13 interposed therebetween. 13 are removed from the surface. As will be described later in detail, the belt cleaning means 20 arranged downstream of the secondary transfer portion N2 with respect to the movement direction of the intermediate transfer belt 13 cleans the outer peripheral surface of the intermediate transfer belt 13 at a position facing the tension roller 15. It has a cleaning blade 29 (abutting member) that abuts on.

[Belt cleaning means 20]
FIG. 2(a) is a virtual cross-sectional view for explaining the mounting position of the cleaning blade 29 when the cleaning blade 29 is not elastically deformed, and FIG. 2(b) is for explaining the structure of the belt cleaning means 20. FIG. It is a schematic cross-sectional view.

The belt cleaning means 20 has a cleaning container 27 and a cleaning acting portion 28 provided in the cleaning container 27 . The cleaning container 27 is configured as part of a frame of an intermediate transfer unit (not shown) having the intermediate transfer belt 13 and the like. The cleaning action portion 28 has a cleaning blade 29 as a cleaning member (contact member) and a support member 30 that supports the cleaning blade 29 . The cleaning blade 29 is an elastic blade made of urethane rubber (polyurethane), which is an elastic material.

The cleaning blade 29 is a plate-like member elongated in the width direction of the intermediate transfer belt 13 (longitudinal direction of the cleaning blade 29) intersecting the moving direction of the intermediate transfer belt 13 (hereinafter referred to as belt conveying direction). The cleaning blade 29 has a free end 29a in contact with the intermediate transfer belt 13 and a fixed end 29b bonded to the support member 30 in the lateral direction. status is fixed. The length of the cleaning blade 29 in the longitudinal direction is 240 mm, the thickness is 2.0 mm, and the hardness of the cleaning blade 29 is 77° according to the JIS K 6253 standard.

The cleaning action portion 28 is configured to be swingable with respect to the surface of the intermediate transfer belt 13 . That is, the support member 30 is supported to be swingable with respect to the surface of the intermediate transfer belt 13 via a swing shaft 32 fixed to the cleaning container 27 . The support member 30 is pressurized by a pressure spring 34 as a biasing means provided in the cleaning container 27, so that the cleaning action portion 28 moves about the swing shaft 32, and the cleaning blade 29 moves toward the intermediate transfer belt. 13 is biased (pressed).

A tension roller 15 is arranged on the inner peripheral side of the intermediate transfer belt 13 so as to face the cleaning blade 29 . The cleaning blade 29 is in contact with the surface of the intermediate transfer belt 13 in the counter direction with respect to the belt conveying direction at a position facing the tension roller 15 . That is, the cleaning blade 29 is brought into contact with the surface of the intermediate transfer belt 13 so that the free end portion 29a in the width direction of the cleaning blade 29 faces the upstream side in the belt conveying direction. Thereby, as shown in FIG. 2B, a blade nip portion 33 (contact portion) is formed between the cleaning blade 29 and the intermediate transfer belt 13 . The cleaning blade 29 scrapes off transfer residual toner from the surface of the moving intermediate transfer belt 13 at the blade nip portion 33 and collects it in the cleaning container 27 .

In this embodiment, the mounting position of the cleaning blade 29 is set as follows. As shown in FIG. 2(a), the set angle θ is 22°, the penetration amount δ is 1.45 mm, and the contact pressure is 5.5 N/mm. Here, the set angle .theta. one surface that is substantially perpendicular to the vertical direction). The penetration amount δ is the length of the cleaning blade 29 overlapping the tension roller 15 in the thickness direction. The contact pressure is defined by the pressing force (linear pressure in the longitudinal direction) from the cleaning blade 29 at the blade nip portion 33, and is measured using a film-type pressure measuring system (trade name: PINCH, manufactured by Nitta Co., Ltd.). be done. By setting in this way, it is possible to suppress curling and slip noise of the cleaning blade 29 in a high-temperature and high-humidity environment (room temperature 30° C., humidity 80%), and obtain good cleaning performance. In addition, by setting in this way, poor cleaning can be suppressed in a low-temperature and low-humidity environment (room temperature 15° C., humidity 10%), and good cleaning performance can be obtained.

Further, when the intermediate transfer belt 13 and the cleaning blade 29 are new, there is no toner in the blade nip portion 33 and the frictional resistance tends to increase. When this frictional resistance increases, the cleaning blade 29, which is in contact with the intermediate transfer belt 13 in the counter direction, is brought into contact with the intermediate transfer belt 13 in the belt conveying direction (curling), and slip noise occurs. Abnormal noise may occur. When curling occurs, it becomes difficult for the cleaning blade 29 to dam up the toner remaining on the intermediate transfer belt 13, which may result in defective cleaning.

Therefore, the image forming apparatus 100 of this embodiment is configured to apply graphite fluoride (Cefbon CMA: manufactured by Central Glass Co., Ltd.) as an initial lubricant to the end portion 29a of the new cleaning blade 29 before image formation. . That is, when the intermediate transfer belt 13 and the cleaning blade 29 are new, graphite fluoride functions as a lubricant, and after image formation is started, the toner supplied from each developing means 4 acts as a lubricant. function as As a result, it is possible to suppress an increase in frictional resistance at the blade nip portion 33, thereby suppressing curling of the cleaning blade 29 and generation of abnormal noise.

The rubber hardness of the cleaning blade 29 is preferably in the range of 70° or more and 80° or less according to the JIS K 6253 standard, although it is appropriately selected according to the material of the intermediate transfer belt 13 and the like. If the rubber hardness is lower than the above range, the wear amount of the end portion 29a of the cleaning blade 29 increases due to use, and durability may decrease. Chipping or the like may occur due to friction with the transfer belt 13 .

The contact pressure of the cleaning blade 29 is preferably in the range of 4.0 N/mm or more and 7.0 N/mm or less. If the contact pressure is smaller than the above range, good cleaning performance may not be obtained, and if it is larger than the above range, the load for rotating the intermediate transfer belt 13 may become too large.

[Driving Configuration of Image Forming Apparatus]
FIG. 3 is a schematic diagram for explaining the drive configuration of each photosensitive drum 1 and intermediate transfer belt 13 in this embodiment. As shown in FIG. 3, in this embodiment, a driving force is transmitted to the cartridge 9d by a motor M1 as a first driving source to rotate the photosensitive drum 1d and to rotate the intermediate transfer belt 13. ing. A motor M2 as a second drive source transmits driving force to each of the cartridges 9a to 9c to rotationally drive the photosensitive drums 1a to 1c. With this configuration, the number of motors can be reduced from five to two compared to a configuration in which the photosensitive drums 1a to 1d and the intermediate transfer belt 13 are driven by separate motors.

Further, in this embodiment, by connecting a gear (not shown) fixed to the rotation shaft of the photosensitive drum 1d and a gear (not shown) fixed to the rotation shaft of the developing roller 41d, The driving force is transmitted to the developing means 4d. That is, when the photosensitive drum 1d is driven to rotate, the developing roller 41d, the supply roller 43d, and the stirring member 11d, which will be described later, rotate in the developing means 4d.

[Cartridge 9]
Next, the configuration of the cartridges 9a to 9d in this embodiment will be described using the cartridge 9a. FIG. 4(a) is a schematic cross-sectional view of the cartridge 9d viewed from the longitudinal direction (rotational axis direction). FIG. 4(b) is a schematic cross-sectional view of the cartridge 9a when it is new, viewed from the longitudinal direction (rotational axis direction).

As shown in FIG. 4A, the developing means 4a includes a developing roller 41a, a supply roller 43a, a developing blade 44a, an opening 45a, a storage chamber 46a for storing toner, and a toner storage chamber provided above the developing roller 41a. and a developing chamber 47a in which the supply roller 43a is housed. In this embodiment, the toner used is a non-magnetic spherical toner which is negatively charged as a normal polarity and has a particle size of 7 μm. Silica particles (external additive particles) having a particle size of 20 nm are added to the surface of the toner as a toner external additive.

The developing blade 44a is in contact with the developing roller 41a in a direction counter to the direction of rotation of the developing roller 41a (direction of arrow R4 in the figure), and controls the coating amount of the toner supplied by the supply roller 43a and applies charge. The developing blade 44a is made of a thin plate-like member, and uses the spring elasticity of the thin plate to form contact pressure, and the surface of the developing blade 44a is brought into contact with the toner and the developing roller 41a. In this embodiment, as the developing blade 44a, a 0.1 mm-thick leaf-spring-shaped SUS thin plate coated with a semi-conductive resin is used. Further, the development blade 44a is configured to contact the surface of the development blade 44a with the toner carried by the development roller 41a by forming contact pressure using the spring elasticity of the thin plate.

A predetermined voltage is applied from a developing blade power supply 81 to the developing blade 44a. As a result, the toner is negatively charged and its layer thickness is regulated by the discharge between the developing blade 44a and the developing roller 41a and the triboelectrification caused by the friction between the developing blade 44a and the developing roller 41a. In this embodiment, the voltage output from the developing blade power supply 81 is controlled so that the potential difference of the developing blade 44a with respect to the potential of the developing roller 41a is ΔV=-100V during image formation.

When the developing roller 41a is new, silicone particles (Tospearl 120, manufactured by Momentive Performance Materials Co., Ltd.) having a particle size of 2 μm are applied as an initial lubricant to the developing roller 41a. As a result, it is possible to reduce the frictional force generated between the developing roller 41a and the developing blade 44a when the developing roller 41a is new, thereby suppressing the occurrence of deformation (curling) of the developing blade 44a. After the image formation is performed, the toner intervenes between the developing roller 41a and the developing blade 44a, so that the frictional force can be kept below a certain level. Therefore, the silicone particles applied to the developing roller 41a when new are removed from the developing roller 41a during the preparatory operation for image formation, which is executed after the new cartridge 9a is installed in the main body of the image forming apparatus 100. . In this embodiment, silicone particles are used as the initial coating agent, but the present invention is not limited to this, as long as it has lubricity and environmental resistance, the toner may be applied to the developing roller 41a when the roller is new. good.

The supply roller 43a is disposed on the peripheral surface of the developing roller 41a so as to form a predetermined nip portion, and rotates in the illustrated arrow R5 direction. The supply roller 43a is an elastic sponge roller in which a foam is formed on the outer periphery of a conductive core. The supply roller 43a and the development roller 41a are in contact with each other with a predetermined penetration amount to form a contact portion Nd. In this embodiment, the developing roller 41a and the supply roller 43a both have an outer diameter of φ20, and the penetration amount of the supply roller 43a into the developing roller 41a is set to 1.5 mm.

Further, the supply roller 43a and the development roller 41a rotate so as to move in opposite directions at the contact portion Nd. By this operation, the toner is supplied to the developing roller 41a by the supply roller 43a, and the toner remaining on the developing roller 41a as development residue is stripped off. At this time, the amount of toner supplied to the developing roller 41a can be adjusted by adjusting the potential difference between the supply roller 43a and the developing roller 41a. In this embodiment, the value of the voltage (DC voltage) applied from the supply roller power supply 82 to the supply roller 43a is set so that the potential of the developing roller 41a becomes ΔV=+50 V with respect to the potential of the supply roller 43a. ing.

A stirring member 11a (removing member) is provided in the storage chamber 46a. The agitating member 11a agitates the toner stored in the storage chamber 46a and conveys the toner from the opening 45a toward the upper portion of the supply roller 43a in the direction of arrow G in the drawing.

At a position where the developing roller 41a and the photosensitive drum 1a contact each other (hereinafter referred to as a developing portion Ng), the developing roller 41a and the photosensitive drum 1a are rotationally driven so that their surfaces move in the same direction. During image formation, a DC voltage having the same polarity as the charging polarity (negative polarity in this embodiment) of the photosensitive drum 1a is applied from the developing roller power source 80 to the developing roller 41a. As a result, in the developing portion Ng, the negatively charged toner carried on the developing roller 41a moves to the electrostatic latent image portion of the photosensitive drum 1a, and develops the electrostatic latent image to form a toner image.

<Opening operation of sealing member>
As shown in FIG. 4B, when the cartridge 9a is new, the developing chamber 47a in which the developing roller 41a and the supply roller 43a are provided, and the storage chamber 46a for storing the toner are separated by the sealing member 48a. are divided. This is to prevent the toner from leaking from the housing chamber 46a until the user starts using the cartridge.

As shown in FIG. 4B, one end of the sealing member 48a is detachably fixed to the periphery of the opening 45a so as to seal the opening 45a. The other end is fixed to one end of the stirring member 11a. When the user starts using the new cartridge 9a, the stirring member 11a provided in the storage chamber 46a rotates clockwise in FIG. 4 by receiving the driving force from the motor M2. Due to this rotation of the stirring member 11a, the sealing member 48a is peeled off from the periphery of the opening 45a, and the opening 45a is unsealed. Then, the toner can be conveyed from the storage chamber 46a to the developing chamber 47a by the stirring member 11a that rotates clockwise. In this embodiment, the heat sealing method is used to fix the sealing member 48a, but it is not limited to this, and other fixing methods such as ultrasonic welding and double-sided tape may be used.

[Cartridge preparation operation]
In this embodiment, whether or not the cartridges mounted in the main body of the image forming apparatus 100 are new is determined from the detection results of non-volatile storage means (hereinafter referred to as memory) provided in each cartridge 9 . As shown in FIG. 1, each cartridge 9 is provided with a substrate 91 integrating a memory and a transmission section for controlling reading and writing of information to and from the memory. Further, the main body of the image forming apparatus 100 is provided with a transmission section (not shown) for transmitting information from the transmission section of each cartridge 9 to a storage section provided in the CPU 102 .

In this embodiment, when the cartridges are attached to the image forming apparatus 100, the board 91 on the side of each cartridge 9 and the transmission section on the side of the image forming apparatus 100 face each other and come into contact with each other. As a result, the CPU 102 provided on the control board 101 and the memory of each cartridge 9 are electrically connected, and the CPU 102 can read information recorded in the memory and write information to the memory. becomes.

As the memory, an electronic memory made of ordinary semiconductors can be used without particular limitation. Also, in this embodiment, when the cartridges are installed in the image forming apparatus 100, the substrate 91 on the side of each cartridge 9 and the transmission section on the side of the image forming apparatus 100 face each other and are in contact with each other. did. However, the present invention is not limited to this, and when the cartridges are attached to the image forming apparatus 100, the substrate 91 on the side of each cartridge 9 and the transmission section on the side of the image forming apparatus 100 are not brought into contact with each other, and the CPU 102 is controlled by short-distance communication or the like. may read and write information to memory.

In the image forming apparatus 100 of this embodiment, when a new cartridge is installed in the main body of the apparatus, a preparatory operation for performing an image forming operation including an operation of removing the sealing member 48 in the developing means 4 of the new cartridge. is executed. FIG. 5 is a flowchart for explaining control executed when a new cartridge is installed in the main body of image forming apparatus 100 .

As shown in FIG. 5, first, the CPU 102 as a control means reads the information in the memory of each cartridge 9 and determines whether or not the cartridge 9d driven by the motor M1, which is a drive source common to the intermediate transfer belt 13, is new. is detected (step S1). If the cartridge 9d is detected to be new, then it is detected whether or not any one of the cartridges 9a to 9c driven by the motor M2 is new (step S2). Note that even if it is detected in step S1 that the cartridge 9d is not new, the same detection as in step S2 is performed in step S3.

If any one of the cartridges 9a to 9c is detected to be new in step S2, a first preparatory operation is executed (step S4). On the other hand, if it is detected in step S2 that none of the cartridges 9a to 9c are new, a second preparatory operation is executed (step S5). Further, when any one of the cartridges 9a to 9c is detected to be new in step S3, a third preparatory operation is executed (step S6). After the preparatory operations in steps S4 to S6 are executed, CPU 102 determines that image forming apparatus 100 is ready for image formation (step S8).

If none of the cartridges 9a to 9c are found to be new in step S3, the CPU 102 determines that none of the cartridges 9a to 9d are new. Then, the process proceeds to step 8 without executing any of the first to third preparatory operations for image formation. As shown in FIG. 5, in this embodiment, the preparatory operation executed by the CPU 102 differs depending on which cartridge 9 is loaded. The first to third preparatory operations will be described in detail below with reference to FIGS. 6(a) to 6(c).

<First preparation operation>
FIG. 6A is a flowchart for explaining the flow of the first preparatory operation. The first preparatory operation is executed when the CPU 102 detects that the cartridge 9d is new and at least one of the cartridges 9a to 9c is new.

As shown in FIG. 6A, first, in step S101, the CPU 102 starts driving the motor M2 that transmits driving force to various members of the cartridges 9a to 9c. At this time, the photosensitive drums 1a to 1d are separated from the intermediate transfer belt 13. As shown in FIG. Then, in step S102, voltage application to various members of the cartridges 9a to 9c (charging rollers 2a to 2c, developing rollers 41a to 41c, supply rollers 43a to 43c, developing blades 44a to 44c) is started. In this embodiment, a predetermined voltage of -1000 V was applied to the charging rollers 2a to 2c, -300 V to the developing rollers 41a to 41c, -350 V to the supply rollers 43a to 43c, and -450 V to the developing blades 44a to 44c.

After that, in step S103, various members of the cartridges 9a to 9c are rotationally driven while the predetermined voltage is applied until the preparatory operation for image formation in the new cartridge is completed. Here, the preparatory operation for image formation in a new cartridge refers to the operation of peeling off the sealing member 48, supplying toner to the developing chamber 47, and supplying toner from the supply roller 43 to the developing roller 41. .

In step 104, toner as a lubricant is supplied from the developing rollers 41a to 41c to the cleaning blades 31a to 31c provided on the photosensitive drums 1a to 1c. When supplying toner, the CPU 102 first forms electrostatic latent images on the surfaces of the photosensitive drums 1a to 1c charged by the charging rollers 2a to 2c by scanning beams from the exposure means 12a to 12c. At this time, the maximum width of the electrostatic latent image that can form an image in the longitudinal direction of the photosensitive drum 1, which is the length of one rotation of the developing roller 41 in the direction of rotation of the photosensitive drum 1 (the direction of arrow R1 in FIG. 1). form an image. After that, the electrostatic latent image is developed with the toner carried on the developing rollers 41a to 41c to form the toner image for drum supply on the photosensitive drums 1a to 1c. In the operation of supplying toner to the cleaning blades 31a to 31c in this embodiment, the toner image for drum supply is formed 40 times in total at regular intervals. These drum-supply toner images reach the cleaning blade 31 as the photosensitive drum 1 rotates, and function as a lubricant at the position where the cleaning blade 31 and the photosensitive drum 1 contact each other.

Subsequently, in step S105, the photosensitive drums 1a to 1d and the intermediate transfer belt 13 are brought into contact with each other, and in step S106, driving of the motor M1 for transmitting drive to various members of the cartridge 9d and the intermediate transfer belt 13 is started.

Then, in step S107, voltage application to various members of the cartridge 9d (charging roller 2d, developing roller 41d, supply roller 43d, developing blade 44d) is started. In this embodiment, a predetermined voltage of −1000 V was applied to the charging roller 2d, −300 V to the developing roller 41d, −350 V to the supply roller 43d, and −450 V to the developing blade 44d.

After that, in step S108, various members of the cartridge 9d are rotated while the predetermined voltage is applied until the preparatory operation for image formation in the new cartridge 9d is completed. Here, the preparatory operation for image formation in the new cartridge 9d includes the operations of peeling off the sealing member 48d, supplying toner to the developing chamber 47d, and supplying toner from the supply roller 43d to the developing roller 41d. Point. In step S108, toner is supplied from the cartridges 9a to 9c to the intermediate transfer belt 13 along with the execution of the above-described preparatory operation in the cartridge 9d.

The operation of supplying toner from the cartridges 9a to 9c to the intermediate transfer belt 13 is performed as follows. First, on each of the photosensitive drums 1a to 1c, an image can be formed in the longitudinal direction of the photosensitive drum 1 with a length corresponding to two turns of the developing roller 41 in the rotational direction of the photosensitive drum 1 (direction of arrow R1 in FIG. 1). forming an electrostatic latent image of a full width halftone image. After that, the electrostatic latent image is developed with the toner carried on the developing rollers 41a-41c of the developing means 4a-4c to form the toner image for belt supply on the photosensitive drums 1a-1c. Then, the toner images for belt supply formed on the photosensitive drums 1a to 1c are transferred to the intermediate transfer belt 13 at the primary transfer portions N1a to N1c. These belt-supplied toner images reach the belt cleaning means 20 as the intermediate transfer belt 13 moves, are supplied to the blade nip portion 33 where the intermediate transfer belt 13 and the cleaning blade 29 contact, and function as a lubricant. do.

After that, in step S109, after the photosensitive drums 1a to 1d and the intermediate transfer belt 13 are separated, in step S110, toner is supplied to the cleaning blade 31d of the photosensitive drum 1d. The operation of supplying toner to the cleaning blade 31d is performed by forming a toner image for drum supply on the photosensitive drum 1d in the same manner as in step S104 for the cartridges 9a to 9c. These drum-supply toner images reach the cleaning blade 31d as the photosensitive drum 1d rotates, and function as a lubricant at the position where the cleaning blade 31d and the photosensitive drum 1d contact each other.

Then, in step S110, voltage application to various members of the cartridges 9a-9d (charging rollers 2a-2d, developing rollers 41a-41d, supply rollers 43a-43d, developing blades 44a-44d) is stopped. After that, in step S112, the driving of the motors M1 and M2 is stopped, and the first preparatory operation is completed.

In the present embodiment, steps S103 and S104 have been described with respect to all the cartridges 9a to 9c, but these operations may be executed only for new cartridges. For example, when the CPU 102 determines that only the cartridge 9a is new, the operations of steps S103 and S104 may be executed only in the cartridge 9a, or may be executed in conjunction with the cartridges 9a to 9c. good.

Further, in this embodiment, in step S108, the configuration for forming the belt-supply toner image for all the cartridges 9a to 9c has been described, but the present invention is not limited to this. If a predetermined toner can be supplied to the blade nip portion 33, the toner image for belt supply may be formed in one or two of the cartridges 9a to 9c.

<Second preparatory operation>
FIG. 6B is a flowchart for explaining the flow of the second preparatory operation. The second preparatory operation is executed when the CPU 102 detects that the cartridge 9d is new but the cartridges 9a to 9c are not new.

As shown in FIG. 6B, first, the CPU 102 brings the photosensitive drums 1a to 1d and the intermediate transfer belt 13 into contact with each other in step S201. Then, in step S202, the motor M1 for transmitting drive to various members of the cartridge 9d and the intermediate transfer belt 13 and the motor M2 for transmitting drive to various members of the cartridges 9a to 9c are started to be driven.

Subsequently, in step S203, voltage application to various members of the cartridges 9a to 9d (charging rollers 2a to 2d, developing rollers 41a to 41d, supply rollers 43a to 43d, developing blades 44a to 44d) is started. In this embodiment, a predetermined voltage of -1000 V was applied to the charging rollers 2a to 2d, -300 V to the developing rollers 41a to 41d, -350 V to the supply rollers 43a to 43d, and -450 V to the developing blades 44a to 44d.

After that, in step S204, various members of the cartridge 9d are rotated while the predetermined voltage is applied until the preparatory operation for image formation in the new cartridge 9d is completed. Here, the preparatory operation for image formation in the new cartridge 9d includes the operations of peeling off the sealing member 48d, supplying toner to the developing chamber 47d, and supplying toner from the supply roller 43d to the developing roller 41d. Point. In step S204, toner is supplied from the cartridges 9a to 9c to the intermediate transfer belt 13 along with the execution of the preparatory operation in the cartridge 9d.

The operation of supplying toner from the cartridges 9a to 9c to the intermediate transfer belt 13 is performed as follows. First, on each of the photosensitive drums 1a to 1c, an image can be formed in the longitudinal direction of the photosensitive drum 1 with a length corresponding to two turns of the developing roller 41 in the rotational direction of the photosensitive drum 1 (direction of arrow R1 in FIG. 1). forming an electrostatic latent image of a full width halftone image. After that, the electrostatic latent image is developed with the toner carried on the developing rollers 41a-41c of the developing means 4a-4c to form the toner image for belt supply on the photosensitive drums 1a-1c. Then, the toner images for belt supply formed on the photosensitive drums 1a to 1c are transferred to the intermediate transfer belt 13 at the primary transfer portions N1a to N1c. These belt-supplied toner images reach the belt cleaning means 20 as the intermediate transfer belt 13 moves, are supplied to the blade nip portion 33 where the intermediate transfer belt 13 and the cleaning blade 29 contact, and function as a lubricant. do.

After that, in step S205, the photosensitive drums 1a to 1d are separated from the intermediate transfer belt 13, and in step S206, toner is supplied to the cleaning blade 31d of the photosensitive drum 1d. When executing the operation of supplying toner to the cleaning blade 31d, the CPU 102 first forms an electrostatic latent image on the surface of the photosensitive drum 1d charged by the charging roller 2d with the scanning beam from the exposure means 12d. At this time, the maximum width of the electrostatic latent that can form an image in the longitudinal direction of the photosensitive drum 1d, which is the length of one rotation of the developing roller 41d in the rotational direction of the photosensitive drum 1d (direction of arrow R1 in FIG. 1). form an image. After that, the electrostatic latent image is developed with toner carried on the developing roller 41d to form a toner image for drum supply on the photosensitive drum 1d. In the operation of supplying toner to the cleaning blade 31d in this embodiment, the toner image for drum supply is formed 40 times in total at regular intervals. These drum-supply toner images reach the cleaning blade 31d as the photosensitive drum 1 rotates, and function as a lubricant at the position where the cleaning blade 31d and the photosensitive drum 1 contact each other.

Then, in step S207, voltage application to various members of the cartridges 9a-9d (charging rollers 2a-2d, developing rollers 41a-41d, supply rollers 43a-43d, developing blades 44a-44d) is stopped. After that, in step S208, the driving of the motors M1 and M2 is stopped, and the second preparatory operation ends.

In this embodiment, in step S204, the configuration for forming the belt-supply toner image for all the cartridges 9a to 9c has been described, but the present invention is not limited to this. If a predetermined toner can be supplied to the blade nip portion 33, the toner image for belt supply may be formed in one or two of the cartridges 9a to 9c.

<Third preparatory operation>
FIG. 6(c) is a flowchart for explaining the flow of the third preparatory operation. The third preparatory operation is performed when the CPU 102 detects that at least one of the cartridges 9a to 9c is new, although the cartridge 9d is not new.

As shown in FIG. 6(c), first, in step S301, the CPU 102 starts driving the motor M2 that transmits drive to various members of the cartridges 9a to 9c. At this time, the photosensitive drums 1a to 1d are separated from the intermediate transfer belt 13. As shown in FIG. Then, in step S302, voltage application to various members of the cartridges 9a to 9c (charging rollers 2a to 2c, developing rollers 41a to 41c, supply rollers 43a to 43c, and developing blades 44a to 44c) is started. In this embodiment, a predetermined voltage of -1000 V was applied to the charging rollers 2a to 2c, -300 V to the developing rollers 41a to 41c, -350 V to the supply rollers 43a to 43c, and -450 V to the developing blades 44a to 44c.

After that, in step S303, various members of the cartridges 9a to 9c are rotationally driven while the predetermined voltage is applied until the preparatory operation for image formation in the new cartridge is completed. Here, the preparatory operation for image formation in a new cartridge refers to the operation of peeling off the sealing member 48, supplying toner to the developing chamber 47, and supplying toner from the supply roller 43 to the developing roller 41. .

In step 304, toner as a lubricant is supplied from the developing rollers 41a to 41c to the cleaning blades 31a to 31c provided on the photosensitive drums 1a to 1c. When supplying toner, the CPU 102 first forms electrostatic latent images on the surfaces of the photosensitive drums 1a to 1c charged by the charging rollers 2a to 2c by scanning beams from the exposure means 12a to 12c. At this time, the maximum width of the electrostatic latent image that can form an image in the longitudinal direction of the photosensitive drum 1, which is the length of one rotation of the developing roller 41 in the direction of rotation of the photosensitive drum 1 (the direction of arrow R1 in FIG. 1). form an image. After that, the electrostatic latent image is developed with the toner carried on the developing rollers 41a to 41c to form the toner image for drum supply on the photosensitive drums 1a to 1c. In the operation of supplying toner to the cleaning blades 31a to 31c in this embodiment, the toner image for drum supply is formed 40 times in total at regular intervals. These drum-supply toner images reach the cleaning blade 31 as the photosensitive drum 1 rotates, and function as a lubricant at the position where the cleaning blade 31 and the photosensitive drum 1 contact each other.

Then, in step S305, voltage application to various members of the cartridges 9a-9c (charging rollers 2a-2c, developing rollers 41a-41c, supply rollers 43a-43c, developing blades 44a-44c) is stopped. After that, in step S306, the driving of the motor M2 is stopped, and the third preparatory operation ends.

In this embodiment, steps S303 and S304 have explained the configuration in which various operations are performed with respect to all the cartridges 9a to 9c, but these operations may be performed only with new cartridges. For example, when the CPU 102 determines that only the cartridge 9a is new, the operations of steps S303 and S304 may be executed only in the cartridge 9a, or may be executed in conjunction with the cartridges 9a to 9c. good.

[Suppression of Deformation of Cleaning Blade 29]
FIG. 7 is a timing chart explaining the time required for each step in the first preparatory operation of this embodiment.

As shown in FIG. 7, the step that takes the longest time is the operation of supplying toner to the cleaning blade 31 in contact with the photosensitive drum 1 in step S104 and step S110. This is because, in this embodiment, the toner image for drum supply described above is formed 40 times in total at regular intervals, and the toner is supplied from the developing means 4 to the drum cleaning means 3 . The reason for executing such operations in steps S104 and S110 will be described below.

In this embodiment, the developing roller 41 is coated with silicone particles (Tospearl 120, manufactured by Momentive Performance Materials Co., Ltd.) having a particle size of 2 μm as an initial lubricant when the developing roller 41 is new. If the initial coating agent continues to remain on the developing roller 41, the amount of toner held by the developing roller 41 and the amount of charge may become unstable. For this reason, in the present embodiment, when the toner is supplied to the cleaning blade 31 of the photosensitive drum 1, the initial coating agent applied to the developing roller 41 is discharged together with the formation of the toner image for drum supply. Running.

Further, in steps S104 and S110 of the first preparation operation of the present embodiment, a constant amount of toner is discharged in order to stabilize the amount of toner held and the amount of charge carried by the developing roller 41. Is going. In the new cartridge 9, the toner initially supplied from the storage chamber 46 to the developing roller 41 is often toner that has a small particle diameter, a high charge amount, and is easily electrostatically moved. When these toners are present on the developing roller 41, the toner carried on the developing roller 41 may have unstable primary transfer properties and secondary transfer properties due to large variations in particle size and charge amount. . Therefore, in this embodiment, the operation of ejecting a predetermined amount of the initial toner supplied to the developing roller 41 onto the photosensitive drum 1 is executed.

Step S103 takes the second longest time after steps S104 and S110. This is because it is necessary to convey a predetermined amount of toner from the storage chamber 46 to the developing chamber 47 after the sealing member 48 is peeled off, and it is necessary to rotate the stirring member 11 a predetermined number of times or more. In this embodiment, the time required for steps S104 and S110 is 60 seconds (s), and the time required for step S103 is 9 seconds (s).

When a new cartridge 9d is installed in the image forming apparatus 100 and it is necessary to perform a preparatory operation for forming an image in the cartridge 9d, the intermediate transfer belt 13 is rotationally driven while no toner exists on the intermediate transfer belt 13. A situation may arise that causes This is because the intermediate transfer belt 13 is also rotated when various members of the cartridge 9d are rotated by the motor M1. At this time, if the intermediate transfer belt 13 is driven to rotate for a long time without toner on the intermediate transfer belt 13 , the intermediate transfer belt 13 rotates for a long time without supplying lubricant such as toner to the blade nip portion 33 . will continue to do so. As a result, a large frictional force is generated at the blade nip portion 33, and there is a possibility that the tip of the cleaning blade 29 is deformed (curled).

A time t1 shown in FIG. 7 is a time during which the intermediate transfer belt 13 is rotationally driven while toner is not supplied to the intermediate transfer belt 13 during the first preparation operation of this embodiment. Here, as shown in FIG. 7, time t1 is the time required for step S106, the time required for step S107, and the time required for belt supply toner images to be supplied from the photosensitive drums 1a to 1c to the intermediate transfer belt 13 in step S108. It is the sum of the required time until The time t1 in this embodiment is approximately 4.4 seconds (s).

FIG. 8 shows the preparatory operation executed when the CPU 102 detects that the cartridge 9d is new and that at least one or more of the cartridges 9a to 9c is new in a comparative example of this embodiment. It is a flow chart explaining a flow. The comparative example of the present embodiment is substantially the same as the present embodiment in terms of the configuration of the image forming apparatus, etc., except that the flow of the preparation operation is different. Therefore, in the following description, the same reference numerals are assigned to the parts common to the present embodiment, and the comparative example will be described.

As shown in FIG. 8, in the configuration of the comparative example, first, the CPU 102 starts driving the motors M1 and M2 in step S401. At this time, the photosensitive drums 1a to 1d are separated from the intermediate transfer belt 13. As shown in FIG. Then, in step S202, voltage application to various members of the cartridges 9a to 9d (charging rollers 2a to 2d, developing rollers 41a to 41d, supply rollers 43a to 43d, developing blades 44a to 44d) is started. Here, the values of the voltages applied to various members are the same as in this embodiment.

After that, in step S403, various members of the cartridges 9a to 9d are rotationally driven while the predetermined voltage is applied until the preparatory operation for image formation in the new cartridge is completed. In step 404, toner as a lubricant is supplied from the developing rollers 41a to 41d to the cleaning blades 31a to 31d provided on the photosensitive drums 1a to 1d. The preparatory operation for image formation in a new cartridge and the toner supply operation are the same as those of the present embodiment, so the description is omitted.

Subsequently, in step S405, the photosensitive drums 1a to 1d are brought into contact with the intermediate transfer belt 13, and in step S406, toner is supplied to the intermediate transfer belt 13 from the cartridges 9a to 9d. The operation of supplying toner from the cartridges 9a to 9d to the intermediate transfer belt 13 is substantially the same as in this embodiment. First, toner images for belt supply are formed on the respective photosensitive drums 1a to 1d. By transferring these belt supply toner images onto the intermediate transfer belt 13 , the toner is supplied to the blade nip portion 33 where the intermediate transfer belt 13 and the cleaning blade 29 contact each other. After the toner is supplied to the intermediate transfer belt 13, the photosensitive drums 1a to 1d and the intermediate transfer belt 13 are separated in step S407.

Then, in step S408, voltage application to various members of the cartridges 9a-9d (charging rollers 2a-2d, developing rollers 41a-41d, supply rollers 43a-43d, developing blades 44a-44d) is stopped. After that, in step S112, the driving of the motors M1 and M2 is stopped, and the preparatory operation in the comparative example is completed.

In this way, in the comparative example, all the cartridges 9a to 9d start rotating at the same time and perform various preparatory operations. Therefore, in the configuration of the comparative example, the time during which the intermediate transfer belt 13 is rotationally driven in a state where no toner exists on the intermediate transfer belt 13 is longer than that of the present embodiment. Corresponding to FIG. 7, between steps S101 to S108 (substantially corresponding to time t2) excluding steps S106 and S107, in the configuration of the comparative example, the intermediate transfer belt 13 is in a state in which the blade nip portion 33 is not supplied with toner. driven. This time is approximately 73.4 seconds.

<Evaluation results>
Next, regarding the first preparatory operation of the present embodiment shown in the flowchart of FIG. 6A and the preparatory operation of the comparative example shown in the flowchart of FIG. And the presence or absence of abnormal noise was evaluated. In this evaluation, a new intermediate transfer belt 13 is used, and new cartridges 9a to 9d are attached to the image forming apparatus 100 with no toner on the intermediate transfer belt 13, and preparatory operations for the present embodiment and the comparative example are executed. It was carried out by confirming the occurrence of curling and abnormal noise at the time. The evaluation was performed in a state in which graphite fluoride (Cefbon CMA: manufactured by Central Glass Co., Ltd.) was applied as a lubricant to the tip of the cleaning blade 29 in advance. The evaluation was performed in a high-temperature and high-humidity environment with a room temperature of 30° C. and a humidity of 80%, a standard environment with a room temperature of 23° C. and a humidity of 50%, and a low-temperature and low-humidity environment with a room temperature of 15° C. and a humidity of 10%. Table 1 shows the evaluation results.

As shown in Table 1, in the configuration of this example, the cleaning blade 29 was not turned up at the blade nip portion 33, and no abnormal noise was generated. On the other hand, in Comparative Example 1, no curling or abnormal noise occurred in the standard environment, but curling of the cleaning blade 29 occurred during the preparatory operation in the high-temperature, high-humidity environment, and abnormal noise occurred in the low-temperature, low-humidity environment. Occurred. This is because the frictional force at the blade nip portion 33 is increased due to the long rotation driving time of the intermediate transfer belt 13 in the absence of toner. More specifically, since the cleaning blade 29 becomes soft in a high-temperature and high-humidity environment, the frictional force at the blade nip portion 33 increases in the configuration of the comparative example, causing the tip of the cleaning blade 29 to curl. In addition, since the cleaning blade 29 becomes hard in a low-temperature and low-humidity environment, the frictional force at the blade nip portion 33 increases in the configuration of the comparative example. A sound occurred.

Next, the driving torque of the intermediate transfer belt 13 with respect to the rotation time was measured when the intermediate transfer belt 13 was rotationally driven (hereinafter referred to as idling) without supplying toner to the intermediate transfer belt 13 . FIG. 9 shows the torque of the motor M1 when all the cartridges are removed from the image forming apparatus 100 and the cleaning blade 29 is brought into contact with the new intermediate transfer belt 13, and the intermediate transfer belt 13 is driven to rotate. These are the measurement results. The cleaning blade is coated with Cefbon as an initial lubricant. The measurement in FIG. 9 was performed in a high temperature and high humidity environment with a room temperature of 30° C. and a humidity of 80%.

As shown in FIG. 9, the torque of the motor M1 that rotates the intermediate transfer belt 13 tends to increase as the time for rotating the intermediate transfer belt 13 increases. This is because the sephbon applied to the cleaning blade 29 is detached from the cleaning blade 29 immediately after the start of the rotational drive, and the lubricant such as toner is no longer present in the blade nip portion 33, thereby increasing the frictional force in the blade nip portion 33. . From the measurement results shown in FIG. 9, when the intermediate transfer belt 13 was rotationally driven for 48 seconds, the driving torque of the motor M1 reached 3.5 kgf·cm. In the configuration of the image forming apparatus 100 of this embodiment, the cleaning blade 29 was curled at this point. That is, from the measurement results shown in FIG. 9, in order to prevent the cleaning blade 29 from curling up in the image forming apparatus 100 of this embodiment, the driving torque when the intermediate transfer belt 13 is rotationally driven by the motor M1 is It must be 3.5 kgf·cm or less.

In the present embodiment, when the first preparatory operation is executed, the time t1 for rotating the intermediate transfer belt 13 without toner on the intermediate transfer belt 13 is 4.4 seconds. This time is sufficiently short compared to the time (48 seconds) for the cleaning blade 29 to turn over. On the other hand, when the preparatory operation is executed in the configuration of the comparative example, the time t2 during which the intermediate transfer belt 13 is rotationally driven without toner on the intermediate transfer belt 13 is approximately 73.4 seconds. Longer than the time for curling to occur at 29.

As described above, according to this embodiment, in a configuration in which the intermediate transfer belt 13 and at least one of the cartridges 9 are driven by the same drive source, when a new cartridge 9 is installed, the leading edge of the cleaning blade 29 deformation can be suppressed. More specifically, in the preparatory operation executed when a new cartridge 9d is mounted, toner is supplied to the intermediate transfer belt 13 from the cartridges 9a to 9c, which are not common drive sources with the intermediate transfer belt 13, while the cartridge 9d is loaded. Preparatory actions are being taken in As a result, the time during which the intermediate transfer belt 13 is rotationally driven in a state where there is no lubricant such as toner in the blade nip portion 33 is shortened, and deformation of the tip of the cleaning blade 29 can be suppressed.

In this embodiment, the intermediate transfer belt 13 and the cartridge 9d (Bk) are driven by the motor M1, which is the first drive source, but the present invention is not limited to this. The cartridge 9 sharing a drive source with the intermediate transfer belt 13 may be any one of the cartridges 9a to 9d, and the number of cartridges sharing a drive source may be any one to three. In order to minimize the time until the toner is supplied to the intermediate transfer belt 13, the toner should be supplied from the cartridge located closest to the belt cleaning means 20 with respect to the movement direction of the intermediate transfer belt 13. is preferred. In this embodiment, it is the cartridge 9c that is driven by a drive source different from the intermediate transfer belt 13 and that is positioned closest to the belt cleaning means 20 .

Further, whether or not the first and second preparatory operations of this embodiment can be executed may be determined according to the usage status of the intermediate transfer belt 13 and the intermediate transfer unit having the belt cleaning means 20 . For example, when the intermediate transfer unit is new, there is no toner in the blade nip portion 33 . On the other hand, after the intermediate transfer unit has been used to some extent, the toner remaining on the intermediate transfer belt 13 after the secondary transfer has already been collected by the belt cleaning means 20 . may exist. Therefore, when the intermediate transfer unit is new and a new cartridge is inserted into the main body of the image forming apparatus, the CPU 102 controls the above-described first and second processes in order to prevent the cleaning blade 29 from being turned up. It is good also as a structure which performs preparation operation|movement of this. In this way, whether or not the first and second preparatory operations can be executed is determined according to the usage status of the intermediate transfer unit, such as when the intermediate transfer unit is brand new, or when it has been used for a predetermined period (predetermined number of sheets) since it was brand new. may

FIG. 10 is a schematic cross-sectional view showing the configuration of an image forming apparatus according to a modification of this embodiment. In this embodiment, the integrated cartridge 9 having the photosensitive drum 1, the charging roller 2, the drum cleaning means 3, and the developing means 4 has been described, but the present invention is not limited to this. For example, as shown in FIG. 10, a photosensitive drum unit having a photosensitive drum 1, a charging roller 2, and a drum cleaning means 3, and a developing means 4 having a developing roller 41, toner, a supply roller 43, and a developing blade 44 are provided. A separate two-piece cartridge may also be used. In the two-piece cartridge shown in FIG. 10, the photosensitive drum unit and the developing means 4 are detachable from the main body of the image forming apparatus.

Further, in this embodiment, the one-component contact developing system is adopted as the developing system, but a non-contact (jumping) developing system or a two-component developing system may be used as the developing system. effect can be obtained. In the configuration using the two-component development method, the first and second preparatory operations may be performed, for example, during the toner initialization sequence.

(Example 2)
In the first embodiment, the motor M2 as the second drive source transmits a driving force to each of the cartridges 9a to 9c to rotationally drive the photosensitive drums 1a to 1c. On the other hand, in the second embodiment, as shown in FIG. 11, the developing means 4a to 4c are driven not by the motor M2 as the second drive source, but by the motor M3 as the third drive source, and the cartridge 9d is driven. The developing means 4d is driven by a motor M1 as a first drive source. The second embodiment has substantially the same configuration as the first embodiment except that the driving source for driving the developing means 4a to 4c is the motor M3. Therefore, in the following description, the same reference numerals are given to the parts common to the first embodiment, and the description thereof is omitted.

FIG. 11 is a schematic diagram for explaining the driving configuration of each photosensitive drum 1 and intermediate transfer belt 13 in this embodiment. The image forming apparatus of this embodiment includes a motor M1 (first drive source) that drives various members of the cartridge 9d and the intermediate transfer belt 13, and a motor M2 (second drive source) that drives the photosensitive drums 1a to 1c. , and a motor M3 (third drive source) for driving the developing means 4a to 4c. Further, in the image forming apparatus of this embodiment, the developing rollers 41a to 41d can be brought into contact with or separated from the corresponding photosensitive drums 1a to 1d. Specifically, by controlling a development contact/separation motor (not shown) provided in the image forming apparatus by the CPU 102, the development roller 41 can be brought into contact with or separated from the photosensitive drum 1. be.

The driving structure of the cartridges 9a to 9c in this embodiment will be described. Gears (not shown) fixed to the rotation shafts of the supply rollers 43a to 43c are connected to gears (not shown) fixed to the stirring members 11a to 11c. Gears (not shown) fixed to the rotation shafts of the developing rollers 41a to 41c are connected to gears (not shown) fixed to the rotation shafts of the supply rollers 43a to 43c. A rotational driving force from a motor M3 is transmitted to the rotating shaft of the supply roller.

As in the present embodiment, by separately providing a driving source for transmitting the driving force to the developing means 4a to 4c and by configuring the developing roller 41 to contact or separate from the photosensitive drum 1, the first embodiment In addition to the effect of , the following effects can be obtained. That is, since the developing means 4a to 4c and the photosensitive drums 1a to 1c can be individually rotationally driven, it is possible to individually control the driving according to whether or not the rotational driving of each member is necessary. Therefore, it is possible to reduce deterioration in durability due to rubbing between members.

For example, when removing the sealing member 48 as shown in step S103 in the flowchart of FIG. 6A, it is not necessary to rotate the photosensitive drums 1a to 1c. More specifically, the sealing member 48 can be removed by driving the developing means 4a to 4c with the motor M3 while the developing rollers 41a to 41c are separated from the photosensitive drums 1a to 1c. After the sealing member 48 is removed, the motor M2 is started to drive, the developing rollers 41a to 41c are brought into contact with the photosensitive drums 1a to 1c, and the next step S104 is executed. That is, by not rotating the photosensitive drums 1a to 1c when removing the agitating members 11a to 11c, abrasion and friction between the photosensitive drums 1a to 1c and the cleaning blades 31a to 31c and the charging rollers 2a to 2c can be reduced. can be suppressed. As a result, deterioration in durability of the photosensitive drums 1a to 1c can be reduced.

In this embodiment, the drive is transmitted from the motor M3 to the supply rollers 43a to 43c, and the other members of the developing means 4a to 4c are driven through gears fixed to the rotation shafts of the supply rollers 43a to 43c. Although it was set as the structure which transmits, it is not restricted to this. For example, after the drive is transmitted from the motor M3 to the developing rollers 41a to 41c, the drive may be transmitted to other members of the developing means 4a to 4c via gears or the like.

1 photoreceptor drum 4 developing means 9 cartridge 13 intermediate transfer belt 29 cleaning blade M1 motor M2 motor

Claims (12)

a device body;
A first cartridge having a first developing means for forming a toner image on a first image carrier, and a second image carrier carrying a toner image of a color different from that of the first image carrier. a second cartridge having a second developing means for forming a toner image on the
an intermediate transfer member contactable with the first image carrier and the second image carrier;
a contact member that contacts the intermediate transfer body to form a contact portion and collects toner remaining on the intermediate transfer body;
a first drive source for rotationally driving the intermediate transfer member;
a second drive source that is different from the first drive source and that transmits a drive force to the second image carrier;
a third driving source that transmits a driving force to the second developing means;
The intermediate transfer member is rotated by the first drive source, the drive force is transmitted from the second drive source to the second image bearing member , and the drive force is applied to the second developing means by the third drive source. By transmitting the toner, a supply operation for supplying toner from the second developing means to the contact portion via the second image bearing member and a preparatory operation for image formation can be executed. and a control unit for controlling,
In an image forming apparatus in which the first cartridge and the second cartridge are detachable with respect to the apparatus main body,
The control unit performs control so that when the new first cartridge is inserted into the apparatus main body, the supply operation is performed while the second image bearing member is in contact with the intermediate transfer member. death,
When a new second cartridge is inserted into the apparatus main body, the second image bearing member and the intermediate transfer member are separated from each other by the driving force from the second driving source. performing the preparatory operation on the cartridge;
An image forming apparatus , wherein said second developing means can be brought into contact with or separated from said second image bearing member . The new first cartridge includes a sealing member for suppressing leakage of toner accommodated in the first developing means, and a toner supply from the first developing means to the first image bearing member. a removing member for removing the sealing member by receiving a driving force from the first driving source,
2. The image forming apparatus according to claim 1, wherein the removing member removes the sealing member when the control section executes the preparatory operation. a contact member that contacts the first image carrier and collects toner remaining on the first image carrier;
After the sealing member is removed, the control section supplies toner from the first developing device toward a position where the first image bearing member and the contact member are in contact with each other. 3. The image forming apparatus according to claim 2. a device body;
A first cartridge having a first developing means for forming a toner image on a first image carrier, and a second image carrier carrying a toner image of a color different from that of the first image carrier. a second cartridge having a second developing means for forming a toner image on the
an intermediate transfer member contactable with the first image carrier and the second image carrier;
a contact member that contacts the intermediate transfer body to form a contact portion and collects toner remaining on the intermediate transfer body;
a first drive source for rotationally driving the intermediate transfer member;
a second drive source that is different from the first drive source and that transmits a drive force to the second image carrier;
a third drive source that transmits drive to the second developing means;
The intermediate transfer member is rotated by the first drive source, the drive force is transmitted from the second drive source to the second image bearing member, and the drive force is applied to the second developing means by the third drive source. By transmitting the toner, a supply operation for supplying toner from the second developing means to the contact portion via the second image bearing member and a preparatory operation for image formation can be executed. and a control unit for controlling,
In an image forming apparatus in which the first cartridge and the second cartridge are detachable with respect to the apparatus main body,
When a new first cartridge is inserted into the apparatus main body, the control unit performs the preparatory operation in the first cartridge while the second image bearing member is in contact with the intermediate transfer member. and performing the supply operation;
When the new first cartridge and the new second cartridge are inserted into the apparatus main body, the second driving is performed while the second image bearing member and the intermediate transfer member are separated from each other. After executing the preparatory operation in the second cartridge by the driving force from the source, while transmitting the driving force from the second driving source to the second cartridge, the second image carrier is subjected to the intermediate transfer. executing the supply operation by rotating the intermediate transfer member by a driving force from the first drive source while being in contact with the body ;
An image forming apparatus , wherein said second developing means can be brought into contact with or separated from said second image bearing member . The new second cartridge includes a sealing member for suppressing leakage of toner accommodated in the second developing means, and a toner supply from the second developing means to the second image carrier. a removing member for removing the sealing member by receiving a driving force from the second driving source, and
5. The image forming method according to claim 3 , wherein the removal member removes the sealing member by the control section executing the preparatory operation in the second cartridge. Device. 6. The image forming apparatus according to claim 1 , wherein said second drive source transmits drive to said second image bearing member and said second developing means. The new second cartridge includes a sealing member for suppressing leakage of toner accommodated in the second developing means, and a toner supply from the second developing means to the second image carrier. a removing member for removing the sealing member by receiving a driving force from the third driving source,
The control unit removes the sealing member by executing the preparatory operation in the second cartridge while the second developing means is separated from the second image bearing member. 5. The image forming apparatus according to claim 1 , wherein the image forming apparatus comprises: a contact member that contacts the second image carrier and collects toner remaining on the second image carrier;
After the sealing member is removed, the control section supplies toner from the second developing device toward a position where the second image bearing member and the contact member are in contact with each other. 8. The image forming apparatus according to claim 7 . 9. The first driving source according to any one of claims 1 to 8 , wherein the first driving source transmits driving force to the first image bearing member, the first developing means, and the intermediate transfer member. The image forming apparatus according to . wherein the second cartridge is detachable from the apparatus main body, the first cartridge and the second cartridge each have a non-volatile storage means,
10. The control unit detects whether the first cartridge or the second cartridge is new by reading information recorded in the storage unit. 1. The image forming apparatus according to item 1 or 1. 11. The image forming apparatus according to claim 1 , wherein the contact member contacts the intermediate transfer member in a counter direction. The first cartridge integrally includes the first image carrier and the first developing means, and the second cartridge includes the second image carrier and the second developing means. 12. The image forming apparatus according to any one of claims 1 to 11, wherein said means is integrally provided.

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