JP2011242453A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that properly detects a friction coefficient of a surface of an image carrier and adjusts the amount of lubricant to be supplied to the surface of the image carrier, on the basis of the detection value, to properly adjust the friction coefficient of the surface of the image carrier.SOLUTION: The image forming apparatus includes: second driving means 40 for rotating a rotating member 19 in contact with an image carrier 8 at variable speeds; a detection means 60 for detecting a driving load to be generated in first driving means 50 for driving the image carrier 8; a lubricant supplying unit for supplying lubricant to the image carrier 8; and varying means 78 for varying the amount of lubricant to be supplied to the image carrier 8 by the lubricant supplying unit. The varying means 78 is controlled in accordance with the variation of a value detected by the detection means 60 when the second driving means 40 changes the rotation speed of the rotating member 19.

Description

  The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile, or a composite machine thereof, and in particular, supplies a lubricant onto an image carrier such as an intermediate transfer belt or a photosensitive belt. The present invention relates to an image forming apparatus provided with a lubricant supply unit.

  Conventionally, in an image forming apparatus such as a copying machine or a printer, a cleaning device removes deposits such as untransferred toner adhering to an image carrier such as an intermediate transfer belt, an intermediate transfer drum, a photosensitive drum, and a photosensitive belt. A technique is known that uses a lubricant supply unit (lubricant supply device) that supplies a lubricant onto the image carrier in order to reliably clean and reduce wear of the image carrier and cleaning blade ( For example, see Patent Document 1).

In Patent Document 1, etc., a lubricant supply unit (lubricant application device) includes a brush-like rotation member (application member) that is in sliding contact with an intermediate transfer belt (image carrier), a solid lubricant that is in contact with the brush-like rotation member, and a solid lubricant. The pressure spring is configured to urge the lubricant toward the brush-like rotating member. Then, the lubricant is gradually scraped off from the solid lubricant by the brush-like rotating member rotating in a predetermined direction, and the lubricant scraped off by the brush-like rotating member is applied (supplied) to the surface of the intermediate transfer belt.
Here, if the lubricant is excessively supplied to the surface of the intermediate transfer belt and the friction coefficient of the intermediate transfer belt becomes too low, the transfer efficiency of the toner image from the photosensitive drum to the intermediate transfer belt decreases. In addition, it is known that a blurred image and a worm-eaten image are generated on the output image. On the other hand, if the lubricant supplied to the surface of the intermediate transfer belt is insufficient and the friction coefficient of the intermediate transfer belt becomes too high, the cleaning blade that comes into contact with the intermediate transfer belt may be worn or worn. Become. For this reason, it is necessary to optimize the friction coefficient on the surface of the intermediate transfer belt.

  On the other hand, in Patent Document 1 and the like, for the purpose of optimizing the coefficient of friction on the surface of the intermediate transfer belt, the driving torque of the driving roller that drives the intermediate transfer belt is detected, and based on the detection result. A technique for adjusting the amount of lubricant supplied from the lubricant supply unit onto the intermediate transfer belt is disclosed.

The conventional image forming apparatus may not be able to accurately optimize the friction coefficient on the surface of the intermediate transfer belt without accurately detecting the friction coefficient on the surface of the intermediate transfer belt (image carrier). It was. For this reason, there may be a problem that a blurred image or a worm-eaten image is generated on the output image, or a problem that the cleaning blade in contact with the intermediate transfer belt is wrinkled or worn.
This is because the driving torque of the driving roller for driving the intermediate transfer belt and the friction coefficient of the surface of the intermediate transfer belt do not necessarily correspond one-on-one due to the influence of environmental changes, the image area of the toner image, and the like.

  In addition, such problems are not limited to image forming apparatuses that supply lubricant to the surface of the intermediate transfer belt, but may be applied to the surface of other image carriers such as an intermediate transfer drum, a photosensitive belt, and a photosensitive drum. The same applies to an image forming apparatus that supplies a lubricant.

  The present invention has been made to solve the above-described problems, and accurately detects the friction coefficient of the surface of the image carrier, and based on the detected value, the lubricant on the surface of the image carrier. It is an object of the present invention to provide an image forming apparatus capable of adjusting the supply amount to optimize the friction coefficient on the surface of the image carrier with high accuracy.

  An image forming apparatus according to a first aspect of the present invention travels in a predetermined direction, and has an image carrier that carries a toner image on its outer peripheral surface, and rotates in a predetermined direction, and has an outer periphery of the image carrier. A rotating member that comes into contact with the surface; a first driving unit that drives the image carrier; a second driving unit configured to rotate the rotating member and to change the rotation speed of the rotating member; Detection means for detecting a driving load generated in the first drive means, a lubricant supply part for supplying a lubricant to the outer peripheral surface of the image carrier, and a lubricant supply part for supplying the lubricant to the outer peripheral surface of the image carrier. Variable means for varying the supply amount of lubricant to be supplied per unit time, and the variable means is detected by the detection means when the rotational speed of the rotating member is changed by the second driving means. Inspection And it is controlled in accordance with a variation in value.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the invention, the variable unit is configured to detect the rotational speed of the rotating member when the second driving unit decelerates the rotational speed. When the increase rate of the value is smaller than a predetermined range, the supply amount of the lubricant per unit time is decreased, and the detected value when the rotational speed of the rotating member is decelerated by the second driving means When the increase rate of the lubricant is larger than a predetermined range, the supply amount of the lubricant per unit time is controlled to increase.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the image carrier is an endless belt member.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the belt member is an intermediate transfer belt, and the rotating member is brought into contact with the intermediate transfer belt. A secondary transfer roller or a secondary transfer belt that forms a secondary transfer nip portion to which the recording medium is conveyed is used.

  The image forming apparatus according to a fifth aspect of the present invention is the image forming apparatus according to the third aspect, wherein the belt member is an intermediate transfer belt, and the rotating member is brought into contact with the intermediate transfer belt. The photosensitive drum or the photosensitive belt forms a primary transfer nip portion for primary transfer of the toner image onto the intermediate transfer belt.

  The image forming apparatus according to a sixth aspect of the present invention is the image forming apparatus according to any one of the first to fifth aspects, wherein the variable means includes the lubricant supply unit with respect to the image carrier. The supply amount per unit time of the lubricant is varied by contacting and separating.

  The image forming apparatus according to a seventh aspect of the present invention is the image forming apparatus according to any one of the first to fifth aspects, wherein the lubricant supply section slides between the image carrier and the solid lubricant. And a brush-like rotating member having brush bristles around the outer peripheral surface, and the variable means varies the number of rotations of the brush-like rotating member to vary the supply amount of the lubricant per unit time. To do.

  An image forming apparatus according to an eighth aspect of the present invention is the image forming apparatus according to any one of the first to fifth aspects, wherein the lubricant supply section slides between the image carrier and the solid lubricant. And a brush-like rotating member having brush bristles provided on the outer peripheral surface thereof, wherein the variable means varies the contact pressure of the solid lubricant against the brush-like rotating member to change the unit time of the lubricant. The supply amount per unit is variable.

  According to the present invention, the lubricant supply amount is variably controlled in accordance with fluctuations in the driving load of the first driving means for driving the image carrier when the rotational speed of the rotating member that contacts the image carrier is changed. Yes. As a result, the friction coefficient on the surface of the image carrier is accurately detected, and the amount of lubricant supplied to the surface of the image carrier is adjusted based on the detected value, so that the friction coefficient on the surface of the image carrier is reduced. An image forming apparatus that is optimized with high accuracy can be provided.

1 is an overall configuration diagram illustrating an image forming apparatus according to Embodiment 1 of the present invention. It is sectional drawing which shows an image formation part. FIG. 4 is a top view showing the vicinity of an intermediate transfer belt and a secondary transfer roller. It is a block diagram which shows a lubricant supply part. FIG. 3 is a diagram illustrating a state where a lubricant supply unit is separated from an intermediate transfer belt. 6 is a graph showing a relationship between a friction coefficient of an intermediate transfer belt and a driving torque increase rate. It is a flowchart which shows the contact / separation control of a lubricant supply part. It is a block diagram which shows the lubricant supply part in Embodiment 2 of this invention. It is a flowchart which shows control of the rotational speed of the brush-like rotation member in the lubricant supply part of FIG. It is a block diagram which shows the lubricant supply part in Embodiment 3 of this invention. 11 is a flowchart showing control of contact pressure of a solid lubricant with respect to a brush-like rotating member in the lubricant supply unit of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

Embodiment 1 FIG.
A first embodiment of the present invention will be described in detail with reference to FIGS.
First, the configuration and operation of the entire image forming apparatus will be described.
As shown in FIG. 1, four toner containers 32Y, 32M, 32C, and 32K corresponding to the respective colors (yellow, magenta, cyan, and black) are attached to and detached from the toner container accommodating portion 31 above the image forming apparatus main body 100. It is installed freely (changeable).
An intermediate transfer unit 15 is disposed below the toner container housing 31. Image forming portions 6Y, 6M, 6C, and 6K corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged in parallel so as to face the intermediate transfer belt 8 (image carrier) of the intermediate transfer unit 15. .
Although illustration is omitted, toner replenishing devices are respectively disposed below the toner containers 32Y, 32M, 32C, and 32K. The toners stored in the toner containers 32Y, 32M, 32C, and 32K are respectively supplied (supplied) into the developing devices of the image forming units 6Y, 6M, 6C, and 6K by the toner replenishing device.

  Referring to FIG. 2, an image forming unit 6Y corresponding to yellow includes a photosensitive drum 1Y, a charging unit 4Y disposed around the photosensitive drum 1Y, a developing device 5Y (developing unit), a cleaning unit 2Y, It is comprised by the static elimination part (not shown) etc. Then, an image forming process (charging process, exposure process, developing process, transfer process, cleaning process) is performed on the photosensitive drum 1Y, and a yellow image is formed on the photosensitive drum 1Y.

  The other three image forming units 6M, 6C, and 6K have substantially the same configuration as that of the image forming unit 6Y corresponding to yellow except that the color of the toner used is different. A corresponding image is formed. Hereinafter, description of the other three image forming units 6M, 6C, and 6K will be omitted as appropriate, and only the image forming unit 6Y corresponding to yellow will be described.

Referring to FIG. 2, the photosensitive drum 1Y is driven to rotate clockwise in FIG. 2 by a drive motor (not shown). Then, the surface of the photosensitive drum 1Y is uniformly charged at the position of the charging unit 4Y (a charging process).
After that, the surface of the photosensitive drum 1Y reaches the irradiation position of the laser beam L emitted from the exposure device 7 (see FIG. 1), and the electrostatic latent image corresponding to yellow by exposure scanning at this position. Is formed (this is an exposure step).

Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the developing device 5Y, and the electrostatic latent image is developed at this position to form a yellow toner image (developing process).
Specifically, referring to FIG. 2, a two-component developer G composed of toner and a carrier (magnetic carrier) is accommodated in the developing device 5Y. The developer G in the developing device 5Y is adjusted so that the toner concentration (the ratio of the toner in the developer G) detected by a magnetic sensor (not shown) is within a predetermined range. That is, according to the toner consumption in the developing device 5Y, the toner (replenishment toner) is replenished into the second developer transport unit 504Y by the toner replenishing device via the toner replenishing port 64Y.
The toner replenishing device is connected to the toner container 32Y shown in FIG. Although not shown, the toner replenishing device is stored in a driving unit that rotates and drives the toner container 32Y (toner bottle), a toner tank unit that stores toner discharged from the toner container 32Y, and a toner tank unit. A toner conveying section that conveys the toner toward the toner dropping path, and a toner dropping path that causes the toner conveyed by the toner conveying section to fall by its own weight toward the developing device 5Y (second developer conveying section 504Y). Has been.

Referring to FIG. 2, the toner (supplemented toner) replenished into the second developer conveying unit 504Y through the toner replenishing port 64Y is mixed with the developer G by the two conveying screws 505Y and 506Y. While being stirred, the first developer transport unit 503Y and the second developer transport unit 504Y separated by the partition member are circulated.
Thus, the toner in the developer G circulating in the circulation path is attracted to the carrier by frictional charging with the carrier and is carried together with the carrier on the developing roller 501Y having a plurality of magnetic poles formed around it. The developer G carried on the developing roller 501Y is conveyed as the developing roller 501Y rotates in the direction of the arrow, and reaches the position of the doctor blade 502Y. The developer G on the developing roller 501Y is regulated to an appropriate amount at this position, and then conveyed to a position facing the photosensitive drum 1Y (developing area). The toner is attracted to the latent image formed on the photosensitive drum 1Y by the electric field (developing electric field) formed in the developing area.
Here, the developer in the developing device 5Y is adjusted so that the toner ratio (toner concentration) in the developer is within a predetermined range. Specifically, according to the consumption of toner in the developing device 5Y, the toner stored in the toner bottle 32Y is supplied into the second developer transport unit 504Y by the toner supply device via the toner supply port 64Y.

Referring to FIG. 2, after the above-described developing process, the surface of photoconductor drum 1Y reaches a position (a primary transfer nip portion) opposite to intermediate transfer belt 8 and first transfer bias roller 9Y. At this position, the toner image on the photosensitive drum 1Y is transferred onto the intermediate transfer belt 8 as an image carrier (this is a primary transfer step). At this time, a small amount of untransferred toner remains on the photosensitive drum 1Y.
Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the cleaning unit 2Y, and untransferred toner remaining on the photosensitive drum 1Y at this position is mechanically collected by the cleaning blade 2a (in the cleaning process). is there.).
Finally, the surface of the photosensitive drum 1Y reaches a position facing a neutralization unit (not shown), and the residual potential on the photosensitive drum 1Y is removed at this position.
Thus, a series of image forming processes performed on the photosensitive drum 1Y is completed.

The image forming process described above is performed in the other image forming units 6M, 6C, and 6K in the same manner as the yellow image forming unit 6Y. That is, the laser beam L based on the image information is emitted from the exposure unit 7 disposed below the image forming unit onto the photosensitive drums of the image forming units 6M, 6C, and 6K. Specifically, the exposure unit 7 emits a laser beam L from a light source, and irradiates the photosensitive drum through a plurality of optical elements while scanning the laser beam L with a polygon mirror that is rotationally driven.
Thereafter, the toner images of the respective colors formed on the respective photosensitive drums through the developing process are transferred onto the intermediate transfer belt 8 (image carrier) as a belt member in an overlapping manner. In this way, a color image is formed on the intermediate transfer belt 8.

Here, referring to FIG. 1, the intermediate transfer unit 15 includes an intermediate transfer belt 8 as an image carrier, four primary transfer bias rollers 9Y, 9M, 9C, and 9K, a secondary transfer counter roller 12, and a first transfer roller. The tension roller 13, the second tension roller 14, the intermediate transfer cleaning unit 10, the first counter roller 11, the second counter roller 17, and the like. The intermediate transfer belt 8 is an endless belt member that is stretched and supported by a plurality of roller members 9 to 14 and 17 and rotated by one roller member 12 (secondary transfer counter roller). 1 is moved endlessly in the direction of the arrow.
In the first embodiment, the traveling speed (process linear speed) of the intermediate transfer belt 8 as the image carrier is set to 150 mm / second.

The four primary transfer bias rollers 9Y, 9M, 9C, and 9K respectively sandwich the intermediate transfer belt 8 with the photosensitive drums 1Y, 1M, 1C, and 1K to form a primary transfer nip portion. A transfer bias opposite to the toner polarity (+1800 volts in the first embodiment) is applied to the primary transfer bias rollers 9Y, 9M, 9C, and 9K. Note that the primary transfer bias rollers 9Y, 9M, 9C, and 9K are urged in a direction in which the photosensitive drums 1Y, 1M, 1C, and 1K are pressed against each other by a spring (not shown).
The intermediate transfer belt 8 travels in the direction of the arrow, and sequentially passes through the primary transfer nip portions of the primary transfer bias rollers 9Y, 9M, 9C, and 9K. In this way, the toner images of the respective colors on the photosensitive drums 1Y, 1M, 1C, and 1K are primarily transferred while being superimposed on the intermediate transfer belt 8.

  Thereafter, the intermediate transfer belt 8 onto which the toner images of the respective colors are transferred in a superimposed manner reaches a position facing the secondary transfer roller 19 as a rotating member. At this position, the secondary transfer counter roller 12 sandwiches the intermediate transfer belt 8 with the secondary transfer roller 19 as a rotating member to form a nip portion (secondary transfer nip portion). Then, a secondary transfer bias opposite to the toner polarity is applied to the secondary transfer roller 19 (or a secondary transfer bias having the same polarity as the toner polarity is applied to the secondary transfer counter roller 12. It is good.) As a result, the color toner image carried on the intermediate transfer belt 8 (image carrier) as a belt member is transferred onto the recording medium P such as transfer paper conveyed to the position of the secondary transfer nip portion. . At this time, untransferred toner that has not been transferred to the recording medium P remains on the intermediate transfer belt 8.

  Thereafter, the intermediate transfer belt 8 reaches the position of the intermediate transfer cleaning unit 10. At this position, the untransferred toner on the intermediate transfer belt 8 is collected. Specifically, a cleaning blade made of urethane rubber is installed in the intermediate transfer cleaning unit 10 so as to contact the intermediate transfer belt 8 at a predetermined angle and pressure. Then, deposits such as untransferred toner remaining on the intermediate transfer belt 8 are mechanically scraped by the cleaning blade of the intermediate transfer cleaning unit 10 and collected in the intermediate transfer cleaning unit 10. A first opposing roller 11 is installed at a position facing the cleaning blade via the intermediate transfer belt 8, thereby stabilizing the contact pressure of the cleaning blade against the intermediate transfer belt 8.

Thereafter, the intermediate transfer belt 8 reaches the position of the lubricant supply unit 16 (lubricant supply device). At this position, the lubricant is supplied (applied) to the outer peripheral surface of the intermediate transfer belt 8. The configuration and operation of the lubricant supply unit 16 will be described in detail later with reference to FIGS. 4 and 5.
Thus, a series of transfer processes performed on the intermediate transfer belt 8 is completed.

Here, the recording medium P transported to the position of the secondary transfer nip portion is transported from a paper feed unit 26 disposed below the apparatus main body 100 via a paper feed roller 27, a registration roller pair 28, and the like. It has been done.
Specifically, a plurality of recording media P such as transfer paper are stored in the paper supply unit 26 in a stacked manner. When the paper feed roller 27 is driven to rotate counterclockwise in FIG. 1, the uppermost recording medium P is fed toward the rollers of the registration roller pair 28.

  The recording medium P transported to the registration roller pair 28 temporarily stops at the position of the roller nip of the registration roller pair 28 whose rotation drive has been stopped. Then, the registration roller pair 28 is rotationally driven in synchronization with the color image on the intermediate transfer belt 8, and the recording medium P is conveyed toward the secondary transfer nip. In this way, a desired color image is transferred onto the recording medium P.

Thereafter, the recording medium P on which the color image is transferred at the position of the secondary transfer nip portion is conveyed to the position of the fixing portion 20 (fixing device). At this position, the color image (toner image) transferred onto the surface of the recording medium P is fixed on the recording medium P by heat and pressure generated by the fixing roller and the pressure roller.
Thereafter, the recording medium P is discharged to the outside of the apparatus through the rollers of the discharge roller pair 29. The recording media P discharged to the outside of the apparatus by the discharge roller pair 29 are sequentially stacked on the stack unit 30 as an output image.
Thus, a series of image forming processes in the image forming apparatus is completed.

In the first embodiment, the intermediate transfer belt 8 (belt member) as an image carrier is PVDF (vinylidene fluoride), ETFE (ethylene-tetrafluoroethylene copolymer), PI (polyimide), PC. This is an endless belt member in which (polycarbonate) or the like is formed in a single layer or a plurality of layers and a conductive material such as carbon black is dispersed. The intermediate transfer belt 8 has a volume resistivity of about 10 ⁸ to 10 ¹² Ωcm, a surface resistivity of about 10 ⁹ to 10 ¹³ Ωcm, and a thickness of about 80 to 100 μm.
If necessary, a release layer can be coated on the surface of the intermediate transfer belt 8. At that time, materials used for the coating are ETFE (ethylene-tetrafluoroethylene copolymer), PTFE (polytetrafluoroethylene), PVDF (vinylidene fluoride), PEA (perfluoroalkoxy fluororesin), FEP (four A fluororesin such as fluorinated ethylene-hexafluoropropylene copolymer) or PVF (vinyl fluoride) can be used, but is not limited thereto.
Further, as a method for manufacturing the intermediate transfer belt 8, there are a casting method, a centrifugal molding method, and the like, and a step of polishing the surface is performed as necessary.

  Further, the secondary transfer counter roller 12 in contact with the inner peripheral surface of the intermediate transfer belt 8 is in contact with the secondary transfer roller 19 (rotating member) through the intermediate transfer belt 8. Referring to FIG. 3, a gear 52 that meshes with a drive gear 51 installed on a motor shaft of a first drive motor 50 as a first drive means is installed on the shaft portion of the secondary transfer counter roller 12. . Then, the driving force is transmitted from the first driving motor 50 as the first driving means to the secondary transfer counter roller 12, and the secondary transfer counter roller 12 rotates counterclockwise in FIG. The intermediate transfer belt 8 is driven (running driving) in the counterclockwise direction of FIG. 1 by the frictional resistance with the counter roller 12.

  Here, referring to FIG. 3, detection for detecting a drive load (drive torque) generated in the first drive motor 50 (first drive means) is detected on the motor shaft of the first drive motor 50 (first drive means). A torque detector 60 (torque detector) is installed as a means. The torque detector 60 (detecting means) detects a driving load (driving torque) from a current value generated in the first driving motor 50 (first driving means).

The secondary transfer roller 19 as a rotating member is a roller member in which an elastic layer (conductive rubber layer) made of a urethane material (urethane rubber) is formed on a metal core made of stainless steel or the like, and has a resistance. Is set to about 10 ⁶ to 10 ¹⁰ Ω. The secondary transfer roller 19 is in contact with the secondary transfer counter roller 12 via the intermediate transfer belt 8 to form a secondary transfer nip portion.
Then, as described above, a desired electric field is formed between the secondary transfer roller 19 and the secondary transfer counter roller 12 (or the intermediate transfer belt 8), so that it is carried on the intermediate transfer belt 8. The toner image is transferred (secondary transfer) onto the recording medium P at the position of the secondary transfer nip portion. Specifically, in the first embodiment, a predetermined voltage (secondary transfer bias) is applied from a power supply unit (not shown) to the secondary transfer roller 19 to perform a transfer process (secondary transfer process). .

Further, in the first embodiment, as shown in FIG. 3, a drive gear installed on the shaft of the secondary transfer roller 19 (rotating member) on the motor shaft of the second drive motor 40 as the second drive means. A gear 42 meshing with 41 is installed. Then, the driving force is transmitted from the second driving motor 40 as the second driving means to the secondary transfer roller 19, and the secondary transfer roller 19 is rotationally driven in the clockwise direction in FIG.
Here, the second drive motor 40 (second drive means) is a rotation speed variable type motor, and can arbitrarily change the rotation speed (rotation speed) of the secondary transfer roller 19 (rotation member). . In the normal state, the second drive motor 40 (second drive means) is configured such that the linear speed of the secondary transfer roller 19 (the linear speed at the secondary transfer nip portion) is the traveling speed of the intermediate transfer belt 8 (150 mm). The rotational speed of the secondary transfer roller 19 is controlled so as to be equivalent to (/ sec.). When the frictional resistance of the outer peripheral surface of the intermediate transfer belt 8 is measured (detected), the rotation speed of the secondary transfer roller 19 is controlled to be reduced by the second drive motor 40 (second drive means). This will be described in detail later.

Hereinafter, the configuration and operation of the lubricant supply unit 16 (lubricant supply device) in the first embodiment will be described in detail.
FIG. 4 is a configuration diagram showing the lubricant supply unit 16 and shows a state where the lubricant supply unit 16 (brush-like rotating member 16a) is in contact with the intermediate transfer belt 8 (image carrier). On the other hand, FIG. 5 is a diagram showing a state in which the lubricant supply unit 16 (brush-like rotating member 16a) is separated from the intermediate transfer belt 8 (image carrier).
Referring to FIG. 4, the lubricant supply unit 16 includes a brush-like rotating member 16a (brush-like) having a solid lubricant 16b, brush bristles that are slidably in contact with the intermediate transfer belt 8 and the solid lubricant 16b. Roller), a compression spring 16c as urging means for urging the solid lubricant 16b toward the brush-like rotating member 16a, a holding portion 16d for holding the solid lubricant 16b, the brush-like rotating member 16a and the solid lubricant 16b It comprises a holder 16e for holding the compression spring 16c and the holding portion 16d.

  The brush-like rotating member 16a is formed by placing brush hairs (density is about 100,000 per square inch) made of polyester having a length (hair feet) of about 4 mm on a base cloth on a core metal. It is wound in a spiral shape, and its outer diameter is set to about 12 mm.

The brush-like rotating member 16a (rotating member) is rotated by the driving motor 70 so as to contact the intermediate transfer belt 8 traveling in the left direction in FIG. 4 in the forward direction (clockwise rotation in FIG. 4). Drive). Further, the brush-like rotating member 16a is disposed so that the brush bristles are in sliding contact with the solid lubricant 16b and the intermediate transfer belt 8, and when the brush-like rotating member 16a rotates, the lubricant is changed from the solid lubricant 16b to the lubricant. And the lubricant is applied to the outer peripheral surface of the intermediate transfer belt 8. In the first embodiment, the drive motor 70 sets the linear velocity of the brush-like rotating member 16a (the linear velocity at the contact position with the intermediate transfer belt 8) to be 165 mm / second. (It is set slightly faster than the process linear velocity of 150 mm / second).
In addition, a compression spring 16c is disposed on the rear portion of the solid lubricant 16b via a holding portion 16d in order to eliminate contact unevenness between the brush-like rotating member 16a and the solid lubricant 16b. It is biased toward the brush-like rotating member 16a.

In the first embodiment, the solid lubricant 16b is mainly formed of zinc stearate. Specifically, the solid lubricant 16b is preferably prepared by dissolving a lubricating oil additive mainly composed of zinc stearate, having no side effects due to overcoating, and having sufficient lubricity.
Zinc stearate is a typical lamellar crystal powder. A lamellar crystal has a layered structure in which amphiphilic molecules are self-organized, and when a shearing force is applied, the crystal breaks along the layers and is slippery. Accordingly, the surface of the intermediate transfer belt 8 can be engaged with low friction. In other words, the surface of the intermediate transfer belt 8 can be effectively covered with a small amount of lubricant by the lamellar crystal that receives the shearing force and uniformly covers the surface of the intermediate transfer belt 8.

  As the solid lubricant 16b, in addition to zinc stearate, stearic acid groups such as barium stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, etc. The thing which has can be used. In addition, the same fatty acid group zinc oleate, barium oleate, lead oleate, the same compound as stearic acid, zinc palmitate, barium palmitate, lead palmitate, the following compound similar to stearic acid May be used. In addition, caprylic acid, linolenic acid, corinolenic acid and the like can be used as the fatty acid group. In addition, waxes such as candelilla wax, canrunauba wax, rice wax, wax, coconut oil, beeswax, and lanolin can also be used. These easily become organic solid lubricants and have good compatibility with the toner.

  In the first embodiment, the second counter roller 17 (the outer diameter is set to about 16 mm) is installed via the intermediate transfer belt 8 at a position facing the brush-like rotating member 16a. Thereby, the contact pressure of the brush-like rotating member 16a with respect to the intermediate transfer belt 8 is stabilized. In the first embodiment, the bristle of the brush-like rotating member 16a is set to bite into the intermediate transfer belt 8 by about 1 mm. Further, the second counter roller 17 is driven (rotated) in the counterclockwise direction of FIG. 4 by the frictional resistance with the intermediate transfer belt 8.

Here, in the first embodiment, the supply amount (lubricant supply amount) per unit time of the lubricant supplied to the outer peripheral surface of the intermediate transfer belt 8 (image carrier) by the lubricant supply unit 16 is varied. Variable means 75, 76, 78 (contact / separation mechanism) are installed.
Specifically, the variable means (contact / separation mechanism) includes a cam 75 that contacts the holder 16e (lubricant supply unit 16), a cam drive motor 78 connected to the rotating shaft 75a of the cam 75, and a holder 16e (lubricant supply unit 16). ) In a direction away from the intermediate transfer belt 8 and the like. Then, the lubricant supply unit 16 is brought into contact with and separated from the intermediate transfer belt 8 by the variable means 75, 76, 78, so that the lubricant supply amount (supply amount per unit time) supplied to the intermediate transfer belt 8 is reached. Is variable.

More specifically, when the posture of the cam 75 in the rotational direction is in the state shown in FIG. 4 due to the control of the cam drive motor 78 by the control unit 80, the cam 75 causes the holder 16e (to resist the urging force of the tension spring 76. The lubricant supply portion 16) is pushed downward, and the brush-like rotating member 16a (lubricant supply portion 16) comes into contact with the intermediate transfer belt 8. In the state of FIG. 4 (contact state), the lubricant is supplied from the lubricant supply unit 16 to the intermediate transfer belt 8 as described above.
On the other hand, when the cam 75 is rotationally driven in the direction of the arrow by the control of the cam drive motor 78 by the control unit 80 and the posture of the cam 75 in the rotational direction is in the state of FIG. The holder 16e (lubricant supply unit 16) moves upward to a position where it abuts on the bottom dead center of the cam 75, and the brush-like rotating member 16a (lubricant supply unit 16) is separated from the intermediate transfer belt 8. It will be. In the state of FIG. 5 (separated state), the supply of lubricant from the lubricant supply unit 16 to the intermediate transfer belt 8 is interrupted.
As described above, the lubricant supply unit 16 is brought into contact with and separated from the intermediate transfer belt 8 by the variable means 75, 76, and 78, so that the amount of lubricant supplied to the intermediate transfer belt 8 (supply per unit time). However, these variable controls are performed according to the magnitude of the fluctuation of the detection value detected by the torque detector 60 (detection means).

Hereinafter, the characteristic configuration and operation of the image forming apparatus according to the first embodiment will be described in detail.
As described above, when the lubricant is applied onto the intermediate transfer belt 8 by the lubricant supply unit 16, the friction coefficient of the intermediate transfer belt 8 is reduced. When the lubricant is not applied onto the intermediate transfer belt 8, the friction coefficient of the intermediate transfer belt 8 increases due to the untransferred toner that has not been transferred onto the recording medium P. However, there is a problem even if the frictional resistance of the intermediate transfer belt 8 decreases too much, and various problems occur if the frictional resistance is not maintained within a predetermined appropriate range (0.25 to 0.35). .
Specifically, when the frictional resistance of the intermediate transfer belt 8 becomes larger than 0.35, the untransferred toner slips through the position of the cleaning blade of the intermediate transfer cleaning unit 10 to cause a cleaning failure. The edges of the camera will drown. On the other hand, if the friction coefficient of the intermediate transfer belt 8 is lower than 0.25, the transfer efficiency from the intermediate transfer belt 8 to the recording medium P is lowered, and a blurred image or worm-eaten image is displayed on the output image. (In either case, a part of the image is lost).

  Therefore, in the first embodiment, the friction coefficient of the intermediate transfer belt 8 (image carrier) is accurately detected, and the lubricant supply amount to the intermediate transfer belt 8 by the lubricant supply unit 16 according to the detection result. Is adjusted. Specifically, the variation in the detection value detected by the torque detector 60 (detection means) when the rotation speed of the secondary transfer roller 19 (rotation member) is changed by the second drive motor 40 (second drive means). Accordingly, the variable means 75, 76, 78 (contact / separation mechanism) are controlled.

  More specifically, the variable means 75, 76, 78 (contact / separation mechanism) causes the second drive motor 40 to rotate the rotation speed of the secondary transfer roller 19 at a predetermined ratio (in the first embodiment, 2%). When the rate of increase in the detection value of the torque detector 60 is smaller than a predetermined range (102 to 104%) when the vehicle is decelerated only by the amount of lubricant, the lubricant supplier is reduced so that the amount of lubricant supplied decreases. 16 is separated from the intermediate transfer belt 8 (the state shown in FIG. 5). On the other hand, when the rotation speed of the secondary transfer roller 19 is reduced by a predetermined ratio (2%) by the second drive motor 40, the increase rate of the detection value of the torque detection unit 60 is within a predetermined range (102 If it is larger than ˜104%), the lubricant supply unit 16 is brought into contact with the intermediate transfer belt 8 so as to increase the lubricant supply amount (the state shown in FIG. 4).

By performing such control, the friction coefficient of the surface of the intermediate transfer belt 8 is accurately detected, and the amount of lubricant supplied to the surface of the intermediate transfer belt 8 is adjusted based on the detected value, and the intermediate transfer belt 8 is adjusted. The friction coefficient on the surface of the transfer belt 8 is accurately maintained within an appropriate range (0.25 to 0.35).
Such control is established because the detection of the friction coefficient of the intermediate transfer belt 8 is detected by the torque detector 60 when the rotation speed of the secondary transfer roller 19 is changed by the second drive motor 40. This is because it is proportional to the fluctuation of the value.

FIG. 6 is a graph showing the relationship between the friction coefficient of the intermediate transfer belt 8 and the driving torque increase rate of the intermediate transfer belt 8, which is performed by the inventor of the present invention using the image forming apparatus according to the first embodiment. The result of the experiment was shown.
In the experiment relating to FIG. 6, several kinds of different intermediate transfer belts 8 having a friction coefficient in the range of 0.17 to 0.45 are prepared, and the rotation speed of the secondary transfer roller 19 is adjusted by the second drive motor 40 at normal time. The rate of increase in the driving torque of the intermediate transfer belt 8 when the speed is reduced (linear speed: 147 mm / second) from (linear speed: 150 mm / second) is measured for each intermediate transfer belt 8. When the rotation speed of the secondary transfer roller 19 is decelerated, the intermediate transfer belt 8 is driven by the first drive motor 50 while slipping the surface of the secondary transfer roller 19. The torque (detected value of the torque detector 60) increases. In FIG. 6, the horizontal axis indicates the friction coefficient of the outer peripheral surface of the intermediate transfer belt 8. In FIG. 6, the vertical axis indicates the drive torque increase rate of the intermediate transfer belt 8, and the increase rate of the detection value detected by the torque detection unit 60 (normal detection value is 100%). Is the percentage of the detected value at the time of deceleration.).
As shown in FIG. 6, it can be seen that there is a proportional relationship between the friction coefficient of the intermediate transfer belt 8 and the drive torque increase rate of the intermediate transfer belt 8 (the increase rate of the detection value of the torque detector 60). Since such a proportional relationship is established without being affected by environmental fluctuations, the image area of the toner image, and the like, the friction coefficient of the surface of the intermediate transfer belt 8 is accurately detected. .

Finally, the contact / separation control of the lubricant supply unit 16 by the variable means 75, 76, 78 (contact / separation mechanism) will be described with reference to the flowchart shown in FIG.
First, the friction coefficient of the intermediate transfer belt 8 is detected at a predetermined timing (steps S0 to S1). Specifically, as described above, the increase rate of the detection value of the torque detector 60 when the rotation speed of the secondary transfer roller 19 is reduced by 2% by the second drive motor 40 is detected. . As a result, when it is determined that the friction coefficient of the intermediate transfer belt 8 is within the appropriate range (0.25 to 0.35), this flow is finished as it is (step S7).

  On the other hand, if it is determined that the friction coefficient of the intermediate transfer belt 8 is not within the appropriate range (0.25 to 0.35), it is further determined whether or not the friction coefficient is smaller than the lower limit value (0.25). (Step S2). As a result, if it is determined that the friction coefficient is smaller than the lower limit value (0.25), it is determined whether the lubricant supply unit 16 (brush-like rotating member 16a) is in contact (step S3). ). When it is determined that the lubricant supply unit 16 is in the contact state, the variable member 75, 76, 78 controls the lubricant supply unit 16 (brush-like rotating member 16a) to be in a separated state. (Step S4), this flow ends (Step S7).

  On the other hand, if it is determined in step S2 that the friction coefficient of the intermediate transfer belt 8 is greater than the lower limit (0.25), it is assumed that the friction coefficient is greater than the upper limit (0.35). Further, it is determined whether the lubricant supply unit 16 (brush-like rotating member 16a) is in contact (step S5). When it is determined that the lubricant supply unit 16 is not in the contact state, the variable member 75, 76, 78 controls the lubricant supply unit 16 (brush-like rotating member 16 a) to be in the contact state. (Step S6), this flow ends (Step S7).

Here, the above-described control is performed by detecting the driving torque increase rate of the intermediate transfer belt 8 accompanied with the deceleration control of the secondary transfer roller 19, so that the image forming operation (image forming process) in the image forming apparatus 100 is performed. It is preferably performed when it is not performed (for example, at the time of warming up or immediately before starting a job).
Thereby, while suppressing the conveyance failure of the recording medium P at the secondary transfer nip portion due to the deceleration control of the secondary transfer roller 19, it is possible to suppress the occurrence of a cleaning failure, a wobbling of the cleaning blade, a blurred image or a worm-eaten image. Can do.

  As described above, in the first embodiment, the intermediate transfer belt 8 is driven when the rotation speed of the secondary transfer roller 19 (rotating member) that contacts the intermediate transfer belt 8 (image carrier) is changed. The amount of lubricant supplied to the intermediate transfer belt 8 is variably controlled in accordance with fluctuations in the driving load of the first driving motor 50 (first driving means). As a result, the friction coefficient of the surface of the intermediate transfer belt 8 is accurately detected, and the amount of lubricant supplied to the surface of the intermediate transfer belt 8 is adjusted based on the detected value, and the surface of the intermediate transfer belt 8 is adjusted. The friction coefficient can be optimized with high accuracy.

Embodiment 2. FIG.
A second embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 8 is a configuration diagram illustrating the lubricant supply unit 16 according to the second embodiment, and corresponds to FIG. 4 according to the first embodiment. FIG. 9 is a flowchart showing the control of the rotation speed of the brush-like rotating member 16a in the lubricant supply unit 16, and corresponds to FIG. 7 in the first embodiment.
The image forming apparatus according to the second embodiment is different from that of the first embodiment in the configuration of variable means for changing the lubricant supply amount.

Similarly to the first embodiment, the image forming apparatus 100 according to the second embodiment also has an intermediate transfer belt 8 (image carrier), a secondary transfer counter roller 12, and a first drive motor 50 (first drive means). ), A torque detection unit 60 (detection unit), a secondary transfer roller 19 (rotation member), a variable speed second drive motor 40 (second drive unit), a lubricant supply unit 16, and the like. .
Also in the second embodiment, when the rotational speed of the secondary transfer roller 19 (rotating member) is changed by the second driving motor 40 (second driving means), the torque detecting unit 60 (detecting means) detects the rotational speed. The amount of lubricant supplied to the intermediate transfer belt 8 is variably controlled in accordance with the change in the detected value.

  Here, referring to FIG. 8, in the second embodiment, the variable means for varying the lubricant supply amount supplied onto the intermediate transfer belt 8 is a variable rotation speed that varies the rotation speed of the brush-like rotating member 16a. This is a mold drive motor 70. That is, the drive motor 70 as a variable means varies the number of rotations of the brush-like rotating member 16a to vary the lubricant supply amount (supply amount per unit time). Then, according to the variation of the detection value detected by the torque detector 60 (detection means) when the rotation speed of the secondary transfer roller 19 (rotation member) is changed by the second drive motor 40 (second drive means). Thus, the drive motor 70 (variable means) is controlled.

  Specifically, the rotational speed of the brush-like rotating member 16a can be varied in two stages by the drive motor 70. When the amount of lubricant supplied to the intermediate transfer belt 8 is to be increased, the rotational speed of the brush-like rotating member 16a is increased, and when the amount of lubricant supplied to the intermediate transfer belt 8 is to be decreased, the brush-like rotating member 16a is increased. The rotational speed of the rotating member 16a is reduced. In addition, when it comprises so that the rotation speed of the brush-like rotation member 16a can be varied in multiple steps, a lubricant supply amount can be adjusted in steps.

With reference to the flowchart shown in FIG. 9, the rotational speed control of the lubricant supply unit 16 (brush-like rotating member 16a) by the drive motor 70 (variable means) will be described. In addition, the description which overlaps with the flow demonstrated using FIG. 7 in the said Embodiment 1 is abbreviate | omitted.
If it is determined in step S2 that the friction coefficient of the intermediate transfer belt 8 is smaller than the lower limit value (0.25), the rotational speed of the lubricant supply unit 16 (brush-like rotating member 16a) is in a decelerating state. It is determined whether or not there is (step S13). When it is determined that the lubricant supply unit 16 is not in the deceleration state, the drive motor 70 (variable means) controls the lubricant supply unit 16 (brush-like rotating member 16a) to be in the deceleration state ( Step S14), this flow ends (Step S7).

  On the other hand, if it is determined in step S2 that the friction coefficient of the intermediate transfer belt 8 is greater than the lower limit (0.25), it is assumed that the friction coefficient is greater than the upper limit (0.35). Further, it is determined whether the lubricant supply unit 16 (brush-like rotating member 16a) is in a speed-up state (step S15). When it is determined that the lubricant supply unit 16 is not in the accelerated state, the drive motor 70 (variable means) controls the lubricant supply unit 16 (brush-like rotating member 16a) to be in the accelerated state. (Step S16), this flow ends (Step S7).

  As described above, also in the second embodiment, similarly to the first embodiment, the rotation speed of the secondary transfer roller 19 (rotating member) that contacts the intermediate transfer belt 8 (image carrier) is changed. The amount of lubricant supplied onto the intermediate transfer belt 8 is variably controlled according to fluctuations in the driving load of the first drive motor 50 (first drive means) that drives the intermediate transfer belt 8 at that time. As a result, the friction coefficient of the surface of the intermediate transfer belt 8 is accurately detected, and the amount of lubricant supplied to the surface of the intermediate transfer belt 8 is adjusted based on the detected value, and the surface of the intermediate transfer belt 8 is adjusted. The friction coefficient can be optimized with high accuracy.

Embodiment 3 FIG.
A third embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 10 is a configuration diagram illustrating the lubricant supply unit 16 according to the third embodiment, and corresponds to FIG. 4 according to the first embodiment. FIG. 11 is a flowchart showing control of the contact pressure of the solid lubricant 16b against the brush-like rotating member 16a in the lubricant supply unit 16, and corresponds to FIG. 7 in the first embodiment. .
In the image forming apparatus according to the third embodiment, the configuration of the variable means for changing the lubricant supply amount is different from those of the respective embodiments.

In the image forming apparatus 100 according to the third embodiment, the intermediate transfer belt 8 (image carrier), the secondary transfer counter roller 12, and the first drive motor 50 (first drive means) are the same as in the above embodiments. ), A torque detection unit 60 (detection unit), a secondary transfer roller 19 (rotation member), a variable speed second drive motor 40 (second drive unit), a lubricant supply unit 16, and the like. .
Also in the third embodiment, when the rotational speed of the secondary transfer roller 19 (rotating member) is changed by the second driving motor 40 (second driving means), it is detected by the torque detection unit 60 (detecting means). The amount of lubricant supplied to the intermediate transfer belt 8 is variably controlled in accordance with the change in the detected value.

  Here, referring to FIG. 10, in the third embodiment, the variable means for varying the amount of lubricant supplied onto intermediate transfer belt 8 is the contact pressure of solid lubricant 16b against brush-like rotating member 16a. The pressure adjustment mechanisms 16f, 75, and 78 are variable. The pressure adjusting mechanism includes a pressure plate 16f connected to the other end of the compression spring 16c, a cam 75 that contacts the pressure plate 16f, a cam drive motor 78 connected to the rotating shaft 75a of the cam 75, and the like. . Then, according to the variation of the detection value detected by the torque detector 60 (detection means) when the rotation speed of the secondary transfer roller 19 (rotation member) is changed by the second drive motor 40 (second drive means). Thus, the pressure adjusting mechanisms 16f, 75, 78 (variable means) are controlled.

Specifically, when it is desired to reduce the amount of lubricant supplied to the intermediate transfer belt 8, the posture of the cam 75 in the rotational direction is maintained in the state shown in FIG. The contact pressure of the solid lubricant 16b against the brush-like rotating member 16a is reduced. In such a case, since the amount of the solid lubricant 16b scraped by the brush-like rotating member 16a is reduced, the amount of lubricant supplied to the intermediate transfer belt 8 is also reduced.
On the other hand, when it is desired to reduce the amount of lubricant supplied to the intermediate transfer belt 8, the cam 75 is rotated 180 degrees from the state of FIG. 10 by the cam drive motor 78 controlled by the controller 80. As a result, the pressure plate 16f is pushed downward by the cam 75 and the use length of the compression spring 16c is shortened, so that the contact pressure of the solid lubricant 16b against the brush-like rotating member 16a is increased. The In such a case, since the amount of the solid lubricant 16b scraped by the brush-like rotating member 16a increases, the amount of lubricant supplied to the intermediate transfer belt 8 also increases.

With reference to the flowchart shown in FIG. 11, the pressure control of the lubricant supply unit 16 (solid lubricant 16b) by the drive motor 70 (variable means) will be described. In addition, the description which overlaps with the flow demonstrated using FIG. 7 in the said Embodiment 1 is abbreviate | omitted.
If it is determined in step S2 that the friction coefficient of the intermediate transfer belt 8 is smaller than the lower limit (0.25), it is determined whether the lubricant supply unit 16 (solid lubricant 16b) is in a reduced pressure state. (Step S23). When it is determined that the lubricant supply unit 16 is not in a reduced pressure state, the lubricant supply unit 16 (solid lubricant 16b) is put in a reduced pressure state by the pressure adjustment mechanisms 16f, 75, and 78 (variable means). Control is performed (step S24), and this flow ends (step S7).

  On the other hand, if it is determined in step S2 that the friction coefficient of the intermediate transfer belt 8 is greater than the lower limit (0.25), it is assumed that the friction coefficient is greater than the upper limit (0.35). Further, it is determined whether the lubricant supply unit 16 (solid lubricant 16b) is in a pressure-increasing state (step S25). When it is determined that the lubricant supply unit 16 is not in the pressure-increasing state, the lubricant supply unit 16 (solid lubricant 16b) is in the pressure-increasing state by the pressure adjustment mechanisms 16f, 75, and 78 (variable means). In this way (step S26), this flow ends (step S7).

  As described above, also in the third embodiment, the rotational speed of the secondary transfer roller 19 (rotating member) that contacts the intermediate transfer belt 8 (image carrier) is changed as in the above embodiments. The amount of lubricant supplied onto the intermediate transfer belt 8 is variably controlled according to fluctuations in the driving load of the first drive motor 50 (first drive means) that drives the intermediate transfer belt 8 at that time. As a result, the friction coefficient of the surface of the intermediate transfer belt 8 is accurately detected, and the amount of lubricant supplied to the surface of the intermediate transfer belt 8 is adjusted based on the detected value, and the surface of the intermediate transfer belt 8 is adjusted. The friction coefficient can be optimized with high accuracy.

  In each of the above embodiments, the present invention is applied to the image forming apparatus 100 using the intermediate transfer belt 8 as an image carrier and the secondary transfer roller 19 as a rotating member. On the other hand, the present invention can be applied to an image forming apparatus using another image carrier (for example, an intermediate transfer drum, a photosensitive belt, a photosensitive drum, or the like). Even in such a case, the image carrier is changed in accordance with the change in the driving load of the first driving means for driving the image carrier when the rotational speed of the rotating member that contacts the image carrier is changed. By variably controlling the amount of lubricant supplied on the body, the same effects as in the above embodiments can be obtained.

In each of the above embodiments, the present invention is applied to the image forming apparatus 100 that uses the secondary transfer roller 19 as a rotating member that contacts the intermediate transfer belt 8. On the other hand, a secondary transfer belt (a belt-like secondary transfer member that abuts on the intermediate transfer belt 8 and forms a secondary transfer nip portion) as a rotating member that abuts on the intermediate transfer belt 8. The present invention can also be applied to an image forming apparatus using. Furthermore, the present invention can also be applied to an image forming apparatus that uses the photosensitive drums 1Y, 1M, 1C, and 1K (or photosensitive belts) as rotating members that contact the intermediate transfer belt 8.
Even in such a case, according to the change in the driving load of the first drive motor 50 that drives the intermediate transfer belt 8 when the rotation speed of the rotating member that contacts the intermediate transfer belt 8 is changed. By variably controlling the amount of lubricant supplied on the intermediate transfer belt 8, the same effects as those of the above embodiments can be obtained.

  It should be noted that the present invention is not limited to the above-described embodiments, and within the scope of the technical idea of the present invention, the embodiments can be modified as appropriate in addition to those suggested in the embodiments. Is clear. In addition, the number, position, shape, and the like of the constituent members are not limited to the above embodiments, and can be set to a number, position, shape, and the like that are suitable for carrying out the present invention.

1Y, 1M, 1C, 1K photosensitive drum,
8 Intermediate transfer belt (belt member, image carrier),
12 Secondary transfer counter roller,
16 Lubricant supply part (lubricant supply device),
16a brush-like rotating member,
16b solid lubricant,
16c compression spring (biasing member),
19 Secondary transfer roller (rotating member),
40 second drive motor (second drive means),
50 1st drive motor (1st drive means),
60 Torque detection part (detection means),
75 cam (variable means),
76 Tension spring (variable means),
78 Cam drive motor (variable means),
100 Image forming apparatus body (apparatus body), P recording medium,

JP 2008-139800 A JP 2009-15287 A

Claims (8)

An image carrier that travels in a predetermined direction and carries a toner image on its outer peripheral surface;
A rotating member that rotates in a predetermined direction and contacts the outer peripheral surface of the image carrier;
First driving means for driving the image carrier;
A second driving means configured to drive the rotary member to rotate and to change the rotational speed of the rotary member;
Detecting means for detecting a driving load generated in the first driving means;
A lubricant supply unit for supplying a lubricant to the outer peripheral surface of the image carrier;
Variable means for varying the supply amount per unit time of the lubricant supplied to the outer peripheral surface of the image carrier by the lubricant supply unit;
With
The image forming apparatus according to claim 1, wherein the variable unit is controlled in accordance with a change in a detection value detected by the detection unit when the rotation speed of the rotating member is changed by the second driving unit.   The variable means has a supply amount of the lubricant per unit time when an increase rate of the detected value when the rotational speed of the rotating member is decelerated by the second driving means is smaller than a predetermined range. If the rate of increase of the detected value when the rotational speed of the rotating member is reduced by the second driving means is greater than a predetermined range, the supply amount of the lubricant per unit time increases. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled so as to perform the operation.   The image forming apparatus according to claim 1, wherein the image carrier is an endless belt member. The belt member is an intermediate transfer belt,
The image according to claim 3, wherein the rotating member is a secondary transfer roller or a secondary transfer belt that forms a secondary transfer nip portion in contact with the intermediate transfer belt to convey a recording medium. Forming equipment. The belt member is an intermediate transfer belt,
The rotating member is a photosensitive drum or a photosensitive belt that abuts on the intermediate transfer belt and forms a primary transfer nip portion for primary transfer of a toner image on the intermediate transfer belt. The image forming apparatus according to claim 3.   6. The variable unit according to claim 1, wherein the supply unit of the lubricant per unit time is changed by contacting and separating the lubricant supply unit with respect to the image carrier. The image forming apparatus described. The lubricant supply unit includes a brush-like rotating member that is in sliding contact with the image carrier and the solid lubricant and has brush hairs provided on the outer peripheral surface thereof.
6. The image forming apparatus according to claim 1, wherein the variable unit varies the number of rotations of the brush-like rotating member to vary the supply amount of the lubricant per unit time. apparatus. The lubricant supply unit includes a brush-like rotating member that is in sliding contact with the image carrier and the solid lubricant and has brush hairs provided on the outer peripheral surface thereof.
The variable means varies the contact pressure of the solid lubricant with respect to the brush-like rotating member to vary the supply amount of the lubricant per unit time. An image forming apparatus according to claim 1.

Images