JP2003058004A - Image forming device and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the increase of driving torque occurring in the case of applying a lubricant on the surface of a member to be cleaned of an image carrier and an intermediate transfer body and to prevent toner and an additive from being fused on the surface of the member to be cleaned over a long term. SOLUTION: This image forming device is equipped with a developing device 17, a density control means 30 forming a reference image for detecting density on the surface of the image carrier 1 and controlling density based on the detected result about the density of the reference image, and a cleaning device 11 equipped with a lubricant applying means 10 for applying the lubricant on the surface of the image carrier 1 and removing the foreign matter on the surface of the image carrier 1 by rubbing the edge part of an elastic blade 2 on the surface of the image carrier 1. Then, a means 16 for stopping or postponing the performance of density detecting operation by the density control means 30 in the case of detecting a specified condition to increase the driving torque of the image carrier 1 is used in the device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and a process cartridge which employs an electrophotographic system and is equipped with a cleaning device having an elastic blade and a lubricant coating mechanism.

[0002]

2. Description of the Related Art Conventionally, a blade cleaning method using an elastic blade as shown in FIG. 7 has a simple structure and is inexpensive as a cleaning means provided in an image forming apparatus adopting an electrophotographic method. Is widely adopted.

In FIG. 7, 101 is a cylindrical member to be cleaned which is rotationally driven in the direction of arrow A, and 102 is a cleaning means.
Is a waste toner collecting container 103, a support member 104 attached to the waste toner collecting container 103, an elastic blade 105 held by the waste toner collecting container 103,
It is composed of a toner collecting sheet 106.

The elastic blade 105 is made of polyurethane rubber and is in contact with the surface of the member 101 to be cleaned in the counter direction. That is, at least the tip of the elastic blade 105 held by the support member 104 contacts the surface of the member to be cleaned 101, and at least a part of the contact surface of the elastic blade 105 to the surface of the member to be cleaned 101 is cleaned.
The member to be cleaned 10 along the downstream direction of the rotation direction of 1
1 is gradually separated from the surface.

On the other hand, in recent years, there is a growing demand for finer output images, and toner particles having a substantially spherical shape capable of obtaining more uniform charging characteristics and toner particles having a smaller particle diameter are being adopted. However, the member to be cleaned 101
It has become possible to clean these toners by increasing the contact pressure of the elastic blade 105 against the toner.

However, when the contact pressure of the elastic blade 105 with respect to the member 101 to be cleaned is increased as described above, the frictional force between the member 101 to be cleaned and the elastic blade 105 increases, so that the respective members are damaged and damaged. Increased risk of wear.

Further, the higher the contact pressure of the elastic blade 105 with respect to the member 101 to be cleaned, the toner, the fluidizing agent added to the toner and the external additive as a tribo-imparting agent, on the surface of the member 101 to be cleaned. 101
There is a tendency that a defect phenomenon called "fusion" that sticks to the surface easily occurs.

In order to prevent the member 101 to be cleaned and the elastic blade 105 from being damaged or worn, for example, FIG.
, A solid lubricant 107 fixedly arranged,
A lubricant applying roller 108 that contacts the lubricant 107 and the member 101 to be cleaned and rotates in a predetermined direction is provided, and the lubricant 107 is applied to the member 101 to be cleaned.
A method of coating on the surface has been proposed.

The above-mentioned means is used for the member 10 to be cleaned.
The frictional force between the surface 1 and the elastic blade 105 is increased, and it is effective in preventing "blade squeaking" caused by the elastic blade causing irregular amplitude motion.
It also has the effect of weakening the adhesion of the toner and external additives to the surface of the member to be cleaned, and the occurrence of "fusion" is suppressed.

As the solid lubricant, for example, a fatty acid metal salt such as zinc stearate or calcium stearate is generally used, and these lubricants are directly applied to the member to be cleaned without using a coating member. The same effect can be obtained even if they are brought into contact with each other.

[0011]

As described above, the blade cleaning method for applying the lubricant to the surface of the member to be cleaned by using the applying member or directly pressing the solid lubricant on the member to be cleaned. With this cleaning device, the frictional force generated between the member to be cleaned and the elastic blade can be reduced, and damage and wear of both members can be prevented.

However, it has been found by the inventors of the present invention that the torque necessary for driving the member to be cleaned may sometimes increase when the lubricant is excessively applied in the cleaning device as described above. Has been issued.

As shown in FIG. 9, in the vicinity of the edge of the elastic blade counter-contacted with the member to be cleaned, the frictional force with the surface of the member to be cleaned and the toner and foreign substances are scratched as the surface of the member to be cleaned moves. By receiving the resistance force at the time of taking, it deforms in the moving direction of the surface of the member to be cleaned.

On the other hand, when the lubricant is excessively supplied to the surface of the member to be cleaned, excess lubricant is accumulated near the edge portion of the elastic blade abutting on the member to be cleaned, and as the member to be cleaned moves. As a result, the elastic blade acts as a resistance when scraping off the toner and foreign matter on the surface of the member to be cleaned, so that the amount of deformation of the elastic blade further increases.

As described above, as the amount of deformation of the elastic blade increases, the contact area between the surface of the member to be cleaned and the elastic blade increases, and the frictional force acting between the two increases, so that it is necessary to drive the member to be cleaned. It is thought that the torque will increase.

Further, as shown in FIG. 10, in a cleaning device in which only the longitudinal ends of a generally used elastic blade are fixed to the device frame with screws or the like, the longitudinal end regions are moved to the longitudinal end regions as the surface of the member to be cleaned moves. In comparison, the deformation amount of the elastic blade in the longitudinal central region where the strength is weak becomes large, and the driving torque of the member to be cleaned is particularly increased.

When the solid lubricant is fixed to the support member for the purpose of simplifying and downsizing the device, the solid lubricant is worn according to the degree of use of the device, so that the application member or the member to be cleaned is cleaned. The amount of lubricant supply of is reduced. Therefore, in such a device, in order to obtain the same lubricating effect as in the initial stage even at the end of life, it is necessary to increase the amount of the coating member or the member to be cleaned invading the solid lubricant at the initial stage as much as possible. Therefore, in the above-described device, the lubricant supply amount inevitably increases at the initial stage of the device, and the driving torque of the member to be cleaned tends to increase at this time.

The amount of deformation of the elastic blade caused by the movement of the surface of the member to be cleaned is shown in FIG.
The larger the penetration amount δ of the elastic blade 105 into the member to be cleaned 101 shown in FIG. 1 and the larger the set angle θ, the stronger the tendency.

On the other hand, in the blade type cleaning device, it is found that a small amount of toner is always present between the elastic blade and the member to be cleaned, and the toner acts as a lubricant to perform stable cleaning. ing.

However, when the member to be cleaned is excessively coated with the lubricant, excess lubricant accumulates in the vicinity of the elastic blade and blocks the toner, and the toner is present between the elastic blade and the member to be cleaned. Getting spicy,
This may be one of the factors that increase the driving force of the member to be cleaned extremely.

The above tendency is particularly caused when the density detection operation is performed in the image forming apparatus which forms the reference image for density detection on the surface of the member to be cleaned and controls the density based on the density detection result. It becomes remarkable. This is because from the viewpoint of minimizing the amount of toner consumption associated with density control, the minimum pattern necessary for density recognition is often printed as a reference image in a narrow area on the member to be cleaned as much as possible.
This is because at this time, the amount of toner flowing into the cleaning device is reduced, so that the amount of toner interposed between the elastic blade and the member to be cleaned is also significantly reduced.

The present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to apply a lubricant to the surface of a member to be cleaned of an image carrier or an intermediate transfer member. An object of the present invention is to provide an image forming apparatus and a process cartridge capable of suppressing an increase in driving torque of a member to be cleaned that occurs and preventing fusion of toner and external additives to the surface of the member to be cleaned for a long period of time.

[0023]

In order to achieve the above object, in the present invention, an image bearing member and an electrostatic latent image formed on the image bearing member are developed with a developer to obtain a toner. A developing unit for forming an image, a density control unit for forming a reference image for density detection on the surface of the image carrier and performing density control based on the detection result of the reference image density, and a lubrication for the surface of the image carrier. An image forming apparatus comprising: a lubricant applying unit that applies an agent; and a cleaning device that removes foreign matter on the surface of the image carrier by rubbing the edge portion of the elastic blade against the surface of the image carrier. When the predetermined condition for increasing the drive torque of the image carrier is detected, the execution of the density detection operation by the density control means is stopped or postponed.

An image carrier, developing means for developing the electrostatic latent image formed on the image carrier with a developer to form a toner image, and intermediate transfer of the toner image formed on the image carrier. Primary transfer means for primary transfer to the body, secondary transfer means for secondarily transferring the toner image on the intermediate transfer body to the surface of the transfer material, and a reference image for density detection on the surface of the image carrier or the intermediate transfer body. Equipped with density control means for performing density control based on the detection result of the image density of the reference image and lubricant application means for applying lubricant to the surface of the intermediate transfer member, and the edge portion of the elastic blade is intermediate An image forming apparatus comprising: a cleaning device that abuts on a surface of a transfer body and rubs a corresponding contact portion on the surface of the intermediate transfer body to remove foreign matter on the surface of the intermediate transfer body. A predetermined condition that increases Wherein the cancel or postpone the execution of the density detection operation by the density control means if.

The amount of lubricant applied at the beginning of the life of the cleaning device is larger than the amount of lubricant applied at the end of the life of the cleaning device, and when the components of the cleaning device containing at least the solid lubricant are replaced with new ones. It is also preferable to suspend or postpone the execution of the concentration detection operation when a predetermined condition is detected.

It is also preferable that the predetermined condition for increasing the driving torque is a high temperature and high humidity environment.

It is also preferable that the predetermined condition for increasing the drive torque is the continuous print mode.

The process cartridge is characterized in that, of the above-mentioned image forming apparatus, at least the image carrier and the cleaning device are integrated and can be attached to and detached from the main body of the image forming apparatus.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions of the components described in this embodiment,
The material, the shape, and the relative arrangement of them should be appropriately changed depending on the configuration of the device to which the invention is applied and various conditions, and the scope of the invention is not limited to the following embodiments.

(Embodiment 1) FIG. 1 is a configuration diagram illustrating an image forming apparatus according to Embodiment 1 of the present invention.

That is, this image forming apparatus includes a photosensitive drum 1 as an image carrier, and a developing device 7 for developing the electrostatic latent image formed on the photosensitive drum 1 with a developer to form a toner image. , Density control means 30 for forming a density detection reference image on the surface of the photosensitive drum 1 and performing density control based on the detection result of the reference image density, and lubrication for applying the lubricant 9 to the surface of the photosensitive drum 1. Brush roller 1 as an agent applying means
And a cleaning device 1 for removing foreign matters on the surface of the photosensitive drum 1 by rubbing the edge portion of the cleaning blade 2 as an elastic blade on the surface of the photosensitive drum 1.
1 and.

The photosensitive drum 1 is formed by forming a photosensitive material film such as OPC on the outer peripheral surface of a cylindrical substrate such as aluminum.

The density control means 30 controls the image density of the toner image by changing the bias applied to either or both of the charging roller 5 and the developing device 7 as the charging means for the photosensitive drum 1. As the density control means, at least a reference image for density detection is formed on the surface of the photosensitive drum 1 and the density of the reference image is detected to determine the value of the bias applied to the developing device 7.

The lubricant 9 of the cleaning device 11 is solid and is arranged apart from the surface of the photosensitive drum 1, and the brush roller 10 is arranged so as to be in contact with both the lubricant 9 and the photosensitive drum 1. 1 Apply lubricant to the surface.

The cleaning blade 2, which is an elastic blade, is made of polyurethane rubber 2b integrally held at the tip of the metal plate 2a, and has a predetermined penetration amount δ and a set angle θ with respect to the photosensitive drum 1. , Are in contact with the rotation direction of the photosensitive drum 1 (arrow B in FIG. 1) from the counter direction. The cleaning blade 2 is fixed to the frame body 3 that also serves as a storage portion for storing toner and foreign matter removed from the surface of the photosensitive drum 1 by fastening both ends of the sheet metal 2a with screws 4. .

For example, the longitudinal dimension of the photosensitive drum 1 is set to 35.
The cleaning blade 2 has a longitudinal dimension of 33 mm.
0 mm.

The material of the cleaning blade 2 is
15-100 [g / cm] within a range in which the cleaning blade 2 penetrates the photosensitive drum 1 does not exceed 1.6 mm.
The hardness was selected so that the contact pressure of 1 was obtained. In the process, it has been found that if the hardness of the cleaning blade is too high, the ability of the cleaning blade 2 to follow the photosensitive drum 1 is impaired due to environmental conditions, and the function as an elastic blade cannot be achieved.
It was judged that it is suitable to use the one of [°] or more and 85 [°] or less (JIS A), and this was used.

The photosensitive drum 1 is rotationally driven in the direction of arrow B in FIG. 1 at a peripheral speed of 100 [mm / sec],
First, the surface is uniformly charged to −700 [v] as the dark portion potential VD by the charging roller 5 as the contact charging means.

Next, according to the first image information, ON / OF
Scan exposure is performed by the scanner 6 as the F-controlled latent image forming means, and the light potential VL is -100 [v].
A first electrostatic latent image of is formed. The electrostatic latent image thus formed is developed and visualized by the developing device 7.

As the developing method, a jumping developing method, a two-component developing method, an FEED developing method and the like are used, and image exposure and reversal developing are often used in combination.

The visualized toner image on the photosensitive drum 1 is charged to the transfer roller 8 which is pressed against the surface of the photosensitive drum 1 with a predetermined pressing force and is rotated by a high voltage power source (not shown). By applying a voltage having a polarity opposite to that of, the transfer is performed on the surface of the transfer material P conveyed to the transfer site at a predetermined timing.

After that, the transfer material P is conveyed to a fixing device (not shown), fixed as a permanent image, and then ejected to the outside of the apparatus.

On the other hand, in the inside of the frame body 3, with respect to the rotation direction of the photosensitive drum 1 (arrow B in FIG. 1), a solid lubricant 9 fixedly arranged at a position upstream of the cleaning blade,
A brush roller 10 is rotatably installed so as to contact the lubricant 9 and the photosensitive drum 1. Brush roller 10
Is rotationally driven in the direction of arrow C in FIG. 1 at a speed of 30 [rpm], and the lubricant 5 scraped off by the brush roller 10 is applied onto the photosensitive drum 1.

At this time, as shown in FIG.
The respective members were arranged so that the invasion amount δ ′ of the brush roller 10 with respect to was uniformly 1 mm over the entire length of the photosensitive drum 1.

On the other hand, even when the amount of intrusion of the brush roller 10 decreases due to wear of the solid lubricant due to use, the solid lubricant can be applied to the surface of the image bearing member sufficiently. Intrusion amount δ ′ of the brush roller 10 with respect to 9
Is set to a high value such that the initial value is 2.0 mm.

A small amount of toner remaining on the surface of the photosensitive drum 1 which has been transferred constitutes the cleaning device 11.
It is removed from the surface of the photosensitive drum 1 by the cleaning blade 2, and the brush roller 10 and the waste toner collecting sheet 1
It is stored in the frame body 3 without being scattered to the outside of the cleaning device 11 by 2.

The brush roller 10 is provided with a scraper 13 at a position downstream of the contact portion with the photosensitive drum 1 with respect to the rotation direction thereof, and the toner and the lubricant trapped by the brush roller 6 are provided each time. It was scraped into the frame body 3. By adopting the above-mentioned configuration, the toner and the like collected from the surface of the photosensitive drum 1 are prevented from returning to the surface of the photosensitive drum 1 again.

In this embodiment, zinc stearate is used as the solid lubricant 9, but iron stearate,
It is possible to use relatively higher fatty acids such as copper stearate, magnesium palmitate, calcium palmitate, manganese oleate and lead oleate.

Further, in the image forming apparatus of this embodiment,
As shown in FIG. 1B, a print mode detection unit 14 that detects whether the apparatus is in continuous printing or single-shot printing (intermittent printing), and detects the temperature and humidity of the environment in which the apparatus is placed. A temperature / humidity detecting means 15 and a judging / controlling means 16 for controlling execution of the concentration detecting operation of the concentration controlling means 30 in accordance with the detection result of the detecting means are postponed.

Then, when a predetermined condition of the print mode and the temperature / humidity environment is detected as the predetermined condition for increasing the driving torque of the photosensitive drum 1, the judgment / control means 16 performs the density detection operation by the density control means 30. Stop or postpone execution.

A process in which the determination / control means 16 determines the execution / suspend of the concentration detection operation relating to the above-described concentration control,
It is shown in the flow chart of FIG.

As shown in the flow chart of FIG. 2, when a print command is issued from an external personal computer (not shown) connected to the main body of the image forming apparatus (S1), the print mode detecting means 14 first sends the print command. The content is compared with the recorded image output by the apparatus, and it is detected how many subsequent recorded images need to be output (S2).

At this time, if there is no remaining print command, the print mode detection means detects this as a single-shot printing state, and the judgment / control means 16 controls so as not to delay the execution of the density detection operation. (S3).

On the other hand, if there are remaining print commands,
The print mode detection means determines that this is a continuous printing state, and the determination / control means 16 controls to execute the temperature / humidity detection by the temperature / humidity detection means (S4).

In the above temperature / humidity detection (S4), if the temperature detected by the temperature / humidity detecting means 15 is less than 30 ° C. and the humidity is less than 80%, the judging / controlling means 16 performs the concentration detecting operation. Control is performed so that the implementation is not postponed (S5).

However, in the temperature / humidity detection (S4), if the temperature detected by the temperature / humidity detection means 15 is 30 ° C. or higher or the humidity is 80% or higher, the judgment / control means 1
6 controls to immediately postpone the execution of the density detection operation (S6).

The above-described detection / judgment is performed every time one printed image is output, and therefore, when the image forming apparatus is continuously printing in a high-temperature or high-humidity environment, a predetermined timing is set. The density detection operation scheduled to be executed in step 1 is controlled so as not to be executed until there are no remaining print commands.

In order to confirm the effect of the image forming apparatus of the present invention, a normal temperature and normal humidity environment (25 ° C./60%), a high temperature and normal humidity environment (35 ° C./60%), a normal temperature and high humidity environment (25 ° C.)
/ 85%) and high temperature and high humidity environment (35 ° C./85%), the continuous mode and the intermittent mode of 1000 sheets of A3 paper at the beginning of the life of the cleaning device with the largest amount of the solid lubricant 9 applied. The respective image formations were performed.

In the image forming apparatus of the present embodiment, the allowable torque value of the motor for driving the photosensitive drum 1 is 1.3 kgf · cm (13
N.cm), and when the torque required to drive the photosensitive drum 1 exceeds this value, the motor immediately loses step and the device malfunctions.

Table 1 below summarizes the maximum torque value in the durability test and the presence or absence of defective operation of the image forming apparatus.
Is.

[0061]

[Table 1]

Further, the maximum torque value and the image forming apparatus when the same durability is performed in the conventional image forming apparatus which does not perform the postponement control of the density detection operation, which is executed in the image forming apparatus of the present embodiment. Table 2 below summarizes the presence or absence of the occurrence of defective operation.

[0063]

[Table 2]

As shown in Tables 1 and 2, in the conventional image forming apparatus, the apparatus due to the increase in the driving torque of the photosensitive drum 1, which tends to occur during continuous printing particularly under the environment of high temperature and high humidity. The malfunction did not occur in the image forming apparatus according to the present embodiment in which control is performed so as to extend the implementation time of the density detection operation under predetermined conditions. That is, it is considered that the density detection operation related to the density control during continuous printing has an influence on the increase in the drive torque of the photosensitive drum 1.

Further, since the surface of the photosensitive drum 1 was coated with the lubricant, fusion did not occur in any of the above-mentioned durability.

In the density detecting operation, when the environmental conditions are small and the influence of durability deterioration of the photosensitive drum 1 is relatively small, the print mode detecting means 14 and the temperature / humidity detecting means 15 detect the result. The judgment / control means 16 may be controlled so as to stop the density detection operation.

On the other hand, for example, the solid lubricant 9 is not fixed and is pressed against the brush roller 10 with a predetermined pressing force so that the amount of the solid lubricant 9 applied does not change throughout the life of the cleaning device 24. Even in the image forming apparatus having the configuration, the effectiveness of the present invention was confirmed as the amount of lubricant applied per recorded image increased.

As described above, in the image forming apparatus according to the present embodiment, toner and external additives are prevented from being fused to the surface of the photosensitive drum 1, and the torque required for driving the photosensitive drum 1 is increased. It was possible to prevent the operation failure of the device.

(Second Embodiment) FIG. 3 shows a block diagram of an image forming apparatus according to a second embodiment of the present invention.

That is, the storage medium 1 in which the life information is stored in advance in the cleaning device 11 containing the solid lubricant 9.
8 is mounted, and at least the storage medium 1 is installed in the main body of the image forming apparatus.
8 is provided with the information reading means 19 for determining the use state of the cleaning device 11 before the judgment / control means 16 judges the execution of the density detection operation. The control is such that the execution of the concentration detection operation is postponed only when the predetermined life has not been reached.

As shown in the flow chart of FIG. 4, when an image forming command is issued from an external personal computer connected to the main body of the image forming apparatus (S11), the judgment / control means 16 is mounted on the cleaning device 11 by the reading means 19. Information regarding the life of the cleaning device 11 is read from the stored storage medium 18 (S12).

The judgment / control means 16 detects the usage state of the cleaning device based on the above-mentioned life information, and judges whether the cleaning device has undergone an image forming operation corresponding to 500 A3 sheets (S13).

When the cleaning device 11 has formed an image corresponding to 500 A3 sheets, the judgment / control means 16 controls so as not to delay the execution of the density detection operation (S).
14).

On the other hand, the cleaning device 11 uses the A3 paper 5
When the image formation of 100 sheets has not been performed, the judgment / control means 16 causes the print mode detection means 14 to describe the content of the print command from the external personal computer connected to the image forming apparatus main body and the recorded image output by the apparatus. And the number of recorded images to be output later is detected (S15).

At this time, if there is no remaining print command, the print mode detection means detects this as a single-shot printing state, and the judgment / control means 16 controls so as not to delay the execution of the density detection operation. (S16).

On the other hand, if there are remaining print commands,
The print mode detection means determines that this is a continuous printing state, and the determination / control means 16 controls the temperature / humidity detection means to execute temperature / humidity detection (S17).

In the temperature / humidity detection (S17) described above, if the temperature captured by the temperature / humidity detection means 15 is less than 30 ° C. and the humidity is less than 80%, the determination / control means 16 performs the concentration detection operation. Control not to postpone implementation (S1
8).

However, when the temperature detected by the temperature / humidity detecting means 15 is 30 ° C. or higher or the humidity is 80% or higher during the temperature / humidity detection, the judging / controlling means 16
Controls to immediately postpone the concentration detection operation (S19).

The above-mentioned detection / judgment is carried out every time one printed image is output. Therefore, when the image forming apparatus is continuously printing in a high temperature or high humidity environment, a predetermined timing is required. The density detection operation scheduled to be executed in step 1 is controlled so as not to be executed until there are no remaining print commands.

It should be noted that the A3 sheet 500 is added to the conventional image forming apparatus.
A3 paper 1 under the high temperature and high humidity environment (35 ° C / 85%) equipped with a cleaning device 11 that has undergone image formation corresponding to one sheet
Although the image formation was performed in the continuous mode and the intermittent mode of 000 sheets, respectively, the operation of the apparatus that occurs when the cleaning device 11 which is new or has not undergone the image formation of 500 sheets of A3 paper is mounted and the image is formed No defects have occurred.

In the image forming apparatus of the present embodiment, the density detection operation related to the density control is postponed only at the beginning of the life of the cleaning apparatus in which the solid lubricant 9 is applied in a relatively large amount, so that the density is made more precise. Accurate concentration control can be performed with.

Further, it is possible to suppress the increase in the torque required to drive the photosensitive drum 1 and prevent the malfunction of the image forming apparatus.

(Third Embodiment) FIG. 5 shows an image forming apparatus according to a third embodiment of the present invention.

This image forming apparatus includes a photosensitive drum 1 as an image carrier, and a developing device 17 for developing the electrostatic latent image formed on the photosensitive drum 1 with a developer to form a toner image.
And the toner image formed on the photosensitive drum 1 to the intermediate transfer member 2
High-voltage power supply 21 as primary transfer means for primary transfer to 0
A secondary transfer means 25 for secondarily transferring the toner image on the intermediate transfer body 20 to the surface of the transfer material; and a reference image for density detection, which is formed on the surface of the photosensitive drum 1 or the intermediate transfer body 20 and the reference image. A density control means 30 for controlling the density based on the density detection result and a brush roller 10 as a lubricant applying means for applying the lubricant 9 on the surface of the intermediate transfer body 20 are provided, and cleaning as an elastic blade is provided. The edge portion of the blade 2 is brought into contact with the surface of the intermediate transfer body 20, and the contact portion is rubbed against the surface of the intermediate transfer body 20 so that the intermediate transfer body 20 is rubbed.
And a cleaning device 24 for removing foreign matter on the surface.

The cleaning device 24 is used for the intermediate transfer member 20.
After the above visible image is secondarily transferred again onto the transfer material to obtain an output image, the residual developer remaining on the surface of the intermediate transfer body 20 and the surface of the transfer belt 22 constituting the secondary transfer means 25 is removed. .

The density control means 30 controls the image density of the toner image by changing the bias applied to either or both of the charging roller 5 and the developing device 17 as the charging means for the photosensitive drum 1. The density control means 30 forms at least a reference image for density detection on the surface of the photosensitive drum 1 and detects the reference image density to determine the value of the bias applied to the developing device 17.

The lubricant 9 of the cleaning device 24 is in a solid state and is arranged apart from the surface of the intermediate transfer body 20, and the brush roller 10 is arranged so as to contact both the lubricant 9 and the intermediate transfer body 20. Lubricant is applied to the surface of the intermediate transfer member 20.

However, in the image forming apparatus of this embodiment,
Intermediate transfer member 20 having a surface that is inferior in smoothness to the photosensitive drum 1.
Since the transfer belt 22 and the transfer belt 22 are used, both the intrusion amount of the cleaning blade 2 and the set angle θ in the cleaning device 24 are set to be smaller than the setting in the cleaning device 11 in the image forming apparatus according to the first embodiment.
The rubbing resistance of the cleaning blade 2 can be reduced.

Further, in this embodiment, the intermediate transfer member 20 is used.
Has a longitudinal dimension of 345 mm, the transfer belt 22 has a longitudinal dimension of 340 mm, and the cleaning blade 2 has a longitudinal dimension of 330 mm.

In FIG. 5, the photosensitive drum 1 is formed by forming a photosensitive material film such as OPC on the outer peripheral surface of a cylindrical substrate such as aluminum.

The photosensitive drum 1 is rotationally driven at a peripheral speed of 100 [mm / sec] in the direction of arrow C in FIG.
First, the surface is uniformly charged to −700 [v] as the dark portion potential VD by the charging roller 5 as the contact charging means.

Next, according to the first image information, ON / OF
Scan exposure is performed by the F-controlled scanner 6, and a first electrostatic latent image of -100 [v] is formed as the bright portion potential VL.

The electrostatic latent image thus formed is developed and visualized by the developing device 17, and the developing device 1
Reference numeral 7 designates a first developing device 17a containing a yellow toner as a first color toner, a second developing device 17b containing a magenta toner as a second color toner, and a third developing device 17b.
The third developing device 17c containing cyan toner as the toner of the color and the fourth developing device 17d containing black toner as the toner of the fourth color are integrated. The electrostatic latent image is developed and visualized by the first developing device 17a containing yellow toner as the first color toner. As a developing method,
A jumping developing method, a two-component developing method, an FEED developing method, or the like is used, and image exposure and reversal developing are often used in combination.

The visualized toner image of the first color is electrostatically transferred (1) to the intermediate transfer member 20 at the first transfer portion facing the intermediate transfer member 20 as the second image carrier that is rotationally driven. Next transcription). The intermediate transfer member 20 has a circumference that is slightly longer than the length of the transfer material.
While being pressed with a predetermined pressing force, the photosensitive drum 1 is rotationally driven in the forward direction with respect to the rotational direction of the photosensitive drum 1 at a peripheral speed substantially equal to the peripheral speed of the photosensitive drum 1. Then, the toner image formed on the surface of the photosensitive drum 20 as described above is transferred to the intermediate transfer body 20 by the high voltage power source 21.
By applying a voltage (primary transfer bias) having a polarity opposite to the charging polarity of the toner, electrostatic transfer (primary transfer) is performed on the surface of the intermediate transfer member 20.

Then, the above-mentioned steps are repeated three times, each time the toner image of the second color developed with magenta toner, the toner image of the third color developed with cyan toner, and the fourth toner image developed with black toner. The toner images of the colors are sequentially transferred and laminated on the surface of the intermediate transfer body 20.

After that, the transfer belt 22 which is in a state of being separated from the surface of the intermediate transfer body 20 is pressed against the surface of the intermediate transfer body 20 with a predetermined pressing force and driven and rotated. The transfer belt 22 is supported by a bias roller 22a and a tension roller 22b.
A voltage (secondary transfer bias) having a polarity opposite to the charging polarity of the toner is applied to a by the high-voltage power supply 23, so that the transfer material conveyed to the second transfer portion at a predetermined timing. The toner image formed on the surface of the intermediate transfer body 20 is collectively transferred (secondarily transferred) to the surface P, and the transfer material P is conveyed to a fixing device (not shown) and fixed as a permanent image, and then outside the machine. Is discharged to.

On the other hand, after the primary transfer and the secondary transfer are respectively finished, a small amount of toner remaining on the surface of the intermediate transfer member 20 is removed from the surface of the photosensitive drum 1 by the cleaning blade 2 constituting the cleaning device 24, and the brush is removed. The roller 10 and the waste toner collecting sheet 12 are stored in the frame 3 without scattering to the outside of the cleaning device 24.

Further, in the image forming apparatus of this embodiment,
A print mode detecting means 14 for detecting whether the apparatus is in continuous printing or single-shot printing (intermittent printing), and a temperature / humidity detecting means 15 for detecting temperature / humidity of an environment in which the apparatus is placed,
A judgment / control unit 16 is installed to control the execution of the concentration detection operation in accordance with the detection result of the detection unit.

Then, the photosensitive drum 1 and the intermediate transfer member 2
When a predetermined condition of the print mode and temperature / humidity environment is detected as the predetermined condition for increasing the driving torque of 0, judgment /
The control means 16 suspends or suspends the execution of the density detection operation by the density control means 30.

Note that the process for the determination / control means 16 to determine the execution / postponement of the density detection operation related to the density control is performed by the image forming apparatus according to the first embodiment as described with reference to the flowchart of FIG. It is controlled in the same way.

In order to confirm the effect of the image forming apparatus of the present embodiment, a normal temperature and normal humidity environment (25 ° C./60
%), High temperature and normal humidity environment (35 ° C / 60%), normal temperature and high humidity environment (25 ° C / 85%), high temperature and high humidity environment (35 ° C / 85%)
In the four environments, the amount of the solid lubricant 9 applied is the largest and the A3 paper 10
Image formation was carried out for each of 00 sheets in the continuous mode and the intermittent mode.

Further, in the image forming apparatus of this embodiment, the intermediate transfer body 20 and the transfer belt 22 are driven by the same single motor, and the allowable torque of the motor is taken into consideration in consideration of the power consumption and the heat generation amount. The value is 2.8 kgf · cm
(28 N · cm). Therefore, when the total sum of the torque values required to drive the intermediate transfer body 20 and the transfer belt 22 exceeds the above-described allowable torque value, the apparatus immediately loses step.

Table 3 below summarizes the maximum torque value in the durability test and the presence / absence of malfunction of the image forming apparatus.
Is.

[0104]

[Table 3]

Further, the maximum torque value and the image forming apparatus when the same durability is performed in the conventional image forming apparatus which does not perform the postponement control of the density detection operation, which is executed in the image forming apparatus of the present embodiment. Table 4 below summarizes the presence or absence of the occurrence of defective operation.

[0106]

[Table 4]

As shown in Tables 3 and 4, in the conventional image forming apparatus, the driving torque increase of the photosensitive drum 1 and the intermediate transfer body 20, which tends to occur during continuous printing, particularly under the environment of high temperature and high humidity. The malfunction of the device caused by
This did not occur in the image forming apparatus according to the present embodiment in which control is performed so as to extend the implementation time of the density detection operation under predetermined conditions. That is, it is considered that the density detection operation related to the density control during continuous printing has an influence on the increase in the drive torque of the photosensitive drum 1 and the intermediate transfer member 20.

Further, since the lubricant was applied to the surface of the intermediate transfer member 20, fusion did not occur in any of the above durability.

In the density detecting operation, the environmental conditions are little changed and the print mode detecting means 14 and the temperature / humidity detecting means 14 are used in a situation in which the photosensitive drum 1 is relatively resistant to the deterioration of durability and the change of transfer efficiency. Depending on the detection result of 15, the judgment / control means 16 may be controlled to stop the density detection operation.

Further, for example, the solid lubricant 9 is not fixed but is pressed against the brush roller 10 with a predetermined pressing force so that the application amount of the solid lubricant 9 does not change throughout the life of the cleaning device 24. Even in the image forming apparatus having the configuration, the effectiveness of the present invention was confirmed as the amount of lubricant applied per recorded image increased.

As described above, in the image forming apparatus of this embodiment, the toner, the external additive, and the like are prevented from being fused to the surface of the intermediate transfer body 20, and the photosensitive drum 1 and the intermediate transfer body 20 are prevented from being fused. It was possible to suppress an increase in torque required for driving and prevent malfunction of the device.

(Embodiment 4) FIG. 6 shows an image forming apparatus and a process cartridge 23 according to Embodiment 4 of the present invention.

As shown in FIG. 6, at least the photosensitive drum 1 and the cleaning device 11 are integrated into a process cartridge 23, which is detachably attached to the main body of the image forming apparatus to perform the image forming operation. It is a thing. In this embodiment, the process cartridge 23 is equipped with the charging roller 5 as a charging means.

In the image forming apparatus of this embodiment, the photosensitive drum 1 is worn or the photosensitive drum 1 is worn by constructing the process cartridge 23 in consideration of the life of the components.
Frame 3 (waste toner accommodating section) with toner removed from the surface
When it becomes impossible to continuously form an image due to, for example, being full, maintenance can be easily performed by replacing the process cartridge 23.

Further, since the torque required to drive the photosensitive drum 1 is reduced, it is possible to stabilize the apparatus in a wide range of environments, and it is possible to prevent the fusion of toner and the like on the surface of the photosensitive drum 1.

[0116]

As described above, according to the present invention,
When the predetermined condition for increasing the drive torque of the image carrier is detected, the increase of the drive torque of the image carrier can be suppressed by stopping or postponing the execution of the density detecting operation by the density control means.

Therefore, it becomes possible to prevent the fusion of the toner and the external additive to the surface of the image bearing member for a long period of time.

When the predetermined condition for increasing the driving torque of the intermediate transfer member is detected, the execution of the density detecting operation by the density control means is stopped or postponed, so that the increase of the driving torque of the intermediate transfer member can be suppressed. .

Therefore, it becomes possible to prevent the fusion of the toner and the external additive to the surface of the intermediate transfer member for a long period of time.

When the amount of lubricant applied at the beginning of the life of the cleaning device is larger than the amount of lubricant applied at the latter stage of the life of the cleaning device, a component of the cleaning device containing a solid lubricant is replaced with a new one. By using a means of stopping or postponing the execution of the density detection operation when a predetermined condition is detected, an increase in drive torque of the image carrier or the intermediate transfer member, which tends to occur particularly at the beginning of the life of the cleaning device, is prevented. I was able to.

Further, when the predetermined condition for increasing the drive torque is a high temperature and high humidity environment, and the image forming operation is continuously performed by the apparatus in the high temperature and high humidity environment, the execution of the density detection operation is suspended or postponed. By using such means, an increase in driving torque of the image carrier or the intermediate transfer member is suppressed under the condition that the frictional force between the elastic blade and the surface of the image carrier or the intermediate transfer member becomes relatively large, and image formation is performed. It was possible to prevent malfunction of the device. Therefore, it becomes possible to prevent the fusion of the toner and the external additive onto the surface of the transfer means for a long period of time.

By setting the predetermined condition for increasing the driving torque to the continuous print mode condition in which the frictional force between the elastic blade and the surface of the image carrier or the intermediate transfer member becomes relatively large, the image carrier or the intermediate transfer member is set. It was possible to prevent the malfunction of the image forming apparatus by suppressing the increase in the driving torque of the image forming apparatus.

In the process cartridge,
By integrating at least the image carrier and the cleaning device and making them attachable to and detachable from the main body of the image forming apparatus, at the time of maintenance of the apparatus or replenishment of consumable parts, by replacing the integrated process cartridges according to the purpose, It has become possible to easily obtain good images at any time.

[Brief description of drawings]

1A is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment of the present invention, and FIG. 1B is a control block diagram.

FIG. 2 is a flowchart illustrating density detection operation control performed by the image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration related to density detection operation control performed by the image forming apparatus according to the second embodiment of the present invention.

FIG. 4 is a flowchart illustrating density detection operation control performed by the image forming apparatus according to the second embodiment of the present invention.

FIG. 5 is a schematic configuration diagram illustrating an image forming apparatus equipped with an intermediate transfer member according to a third embodiment of the present invention.

FIG. 6 is a schematic configuration diagram illustrating a process cartridge according to Embodiment 4 of the present invention and an image forming apparatus that accommodates the process cartridge and forms an image.

FIG. 7 is a schematic configuration diagram illustrating a conventional blade cleaning type cleaning device.

FIG. 8 is a schematic configuration diagram illustrating an image forming apparatus including a conventional lubricant applying unit.

FIG. 9 is an explanatory diagram of a modified example of the cleaning blade when the surface of the member to be cleaned moves.

FIG. 10 is a diagram illustrating a cleaning device having a configuration in which two longitudinal portions of a cleaning blade are fixed.

FIG. 11 is a diagram illustrating an amount of penetration δ of an elastic blade into a member to be cleaned and a set angle θ.

[Explanation of symbols]

1 Photosensitive drum (image carrier) 2 Cleaning blade (elastic blade) 3 frame 5 charging roller 9 Fixed lubricant 10 Brush roller (Lubricant application means) 11,24 Cleaning device 13 scrapers 18 storage media 20 Intermediate transfer body 22 Transfer belt 23 Process cartridge

Continued front page    F-term (reference) 2H027 DA09 DA10 DA13 DA14 DA46                       DB01 EA01 EA05 EK19                 2H134 GA01 GA06 GB02 HA00 HA16                       HD05 HD18 KA28 KA30 KA40                       KB20 LA01                 2H200 FA01 FA02 FA16 GA23 GA33                       GA44 GA47 GA50 GB12 HA02                       HB12 JA02 JB10 JC02 JC19                       JC20 LA12 LB13 LB15 PA20                       PB17 PB27 PB32 PB39

Claims (6)

[Claims] 1. An image carrier, developing means for developing an electrostatic latent image formed on the image carrier with a developer to form a toner image, and a reference image for density detection. An edge portion of the elastic blade is provided with a density control means for performing density control based on the detection result of the reference image density formed on the surface and a lubricant applying means for applying a lubricant on the surface of the image carrier. An image forming apparatus comprising: a cleaning device that removes foreign matter on the surface of the image carrier by rubbing the surface of the image carrier with the cleaning device, when a predetermined condition for increasing the drive torque of the image carrier is detected, An image forming apparatus characterized in that the execution of the density detection operation by the density control means is stopped or postponed. 2. An image carrier, developing means for developing an electrostatic latent image formed on the image carrier with a developer to form a toner image, and a toner image formed on the image carrier. Primary transfer means for primarily transferring to the intermediate transfer body, secondary transfer means for secondarily transferring the toner image on the intermediate transfer body to the surface of the transfer material, and a reference image for density detection as an image carrier or an intermediate transfer body. The edge of the elastic blade is equipped with a density control means for forming an image on the surface and controlling the density based on the detection result of the reference image density, and a lubricant applying means for applying a lubricant to the surface of the intermediate transfer member. An image forming apparatus comprising: a cleaning device configured to bring the intermediate transfer member surface into contact with the intermediate transfer member surface, and to rub the corresponding contact portion on the intermediate transfer member surface to remove foreign matter on the intermediate transfer member surface. Detects predetermined conditions that increase drive torque In this case, the image forming apparatus stops or postpones the execution of the density detection operation by the density control means. 3. The amount of lubricant applied at the beginning of the life of the cleaning device is larger than the amount of lubricant applied at the end of the life of the cleaning device, and the components of the cleaning device containing at least a solid lubricant are replaced with new ones. 3. The image forming apparatus according to claim 1, wherein the execution of the density detecting operation is stopped or postponed when a predetermined condition is detected. 4. The image forming apparatus according to claim 1, wherein the predetermined condition for increasing the driving torque is a high temperature and high humidity environment. 5. The image forming apparatus according to claim 1, wherein the predetermined condition for increasing the driving torque is a continuous print mode. 6. An image forming apparatus according to claim 1, 3, 4 or 5, wherein at least an image carrier and a cleaning device are integrated with each other and can be attached to and detached from a main body of the image forming apparatus. cartridge.