JP2014232257A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can sufficiently remove attached substances, such as an untransferred toner and toner additive attached to the surface of an image carrier with a cleaning rotating body without controlling to vary the rotation speed and rotation direction of the cleaning rotating body, and prevents the acceleration of the wear on the surface of the image carrier resulting from the slide contact of the cleaning rotating body with the image carrier.SOLUTION: An image forming apparatus receives input of a job command, and then determines "the amount of toner input per unit time" input to a brush-like roller (cleaning rotating body) in one job (step S6), and varies the time T3 required for the drive of a photoreceptor drum (image carrier) and the brush-like roller to be stopped in one job on the basis of a result of the determination (steps S7 and S14).

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 more particularly, the surface of an image carrier such as a photosensitive drum, a photosensitive belt, and an intermediate transfer belt. The present invention relates to an image forming apparatus that cleans toner on an image carrier by bringing a cleaning rotator into contact therewith.

  Conventionally, in an image forming apparatus using an electrophotographic system such as a copying machine or a printer, toner on an image carrier that has not been transferred to a transfer medium such as a recording medium or an intermediate transfer belt by a transfer unit is removed by a cleaning apparatus. Techniques for removal are known (see, for example, Patent Documents 1 and 2).

  Specifically, in Patent Documents 1 and 2, a brush roller (cleaning rotator) that rotates in a predetermined direction is disposed on the surface of the photosensitive drum on the downstream side in the rotation direction of the photosensitive drum (image carrier) with respect to the transfer unit. It is installed to abut. Further, on the downstream side in the rotational direction, the cleaning blade is in contact with the surface of the photosensitive drum at a predetermined angle and pressure. Then, the toner (including the untransferred toner and the adhering matter such as toner additive) removed on the photosensitive drum by the brush roller and the cleaning blade is removed, and the cleaning device in which those members are installed is removed. Untransferred toner is collected inside.

  Here, in Patent Documents 1 and 2, there is a problem that the brush roller is slidably contacted with the photosensitive drum with a large linear velocity difference, and the surface of the photosensitive drum is accelerated, and the brush roller has a small linear velocity difference. In order to solve the problem that the adhering matter such as the toner additive adhering to the surface of the photosensitive drum cannot be removed sufficiently by sliding contact with the photosensitive drum, the rotational speed and rotation of the brush roller at a predetermined timing. A technique for changing the direction is disclosed.

In the techniques of Patent Documents 1 and 2 described above, the rotational speed and direction of rotation of the brush roller (cleaning rotator) are varied at a predetermined timing, so that the brush roller has a large linear velocity difference and the photosensitive drum (image carrier). ) And the surface of the photosensitive drum is accelerated, and the brush roller is in contact with the photosensitive drum with a small linear velocity difference. The effect of preventing the problem that the deposits cannot be sufficiently removed can be expected.
However, in the techniques of Patent Documents 1 and 2, in order to change the rotation speed and rotation direction of the brush roller at a predetermined timing, the driving means for rotating only the brush roller alone is driven to rotate the photosensitive drum. The device had to be provided separately from the means, and the device was increased in size and cost.

  The present invention has been made to solve the above-described problems, and it is possible to add non-transferred toner or toner added to the surface of the image carrier without variably controlling the rotation speed and rotation direction of the cleaning rotator. An object of the present invention is to provide an image forming apparatus in which deposits such as agents can be sufficiently removed by a cleaning rotator, and wear of the surface of an image carrier is not promoted by sliding contact with the cleaning rotator.

  An image forming apparatus according to a first aspect of the present invention includes an image carrier that rotates in a predetermined direction while carrying a toner image, and a rotation that rotates in a predetermined direction while contacting the surface of the image carrier. A cleaning rotator for cleaning the toner on the image carrier that has not been transferred at the position of the transfer unit, a driving means for rotationally driving the image carrier and the cleaning rotator, and a job command is input to the apparatus. And calculating means for obtaining a toner input amount per unit time input to the cleaning rotator in one job, and based on the result of the calculating means, the driving means in the one job uses the image. The time until the drive of the carrier and the cleaning rotator is stopped is varied.

  According to the present invention, after a job command is input to the apparatus, the toner input amount per unit time input to the cleaning rotator in one job is obtained, and based on the result, the image carrier and the cleaning rotator are determined in one job. The time until the drive is stopped is variable. As a result, it is possible to sufficiently remove deposits such as untransferred toner and toner additives adhering to the surface of the image bearing member by the cleaning rotator without variably controlling the rotation speed and rotation direction of the cleaning rotator, It is possible to provide an image forming apparatus in which the wear of the surface of the image carrier is not promoted by the sliding contact of the cleaning rotator.

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. 4 is a flowchart illustrating control performed by the image forming apparatus. It is a flowchart which shows the control performed with the image forming apparatus in Embodiment 2 of this invention. It is a flowchart which shows the subroutine in the control of FIG. It is a table | surface figure which shows an example of the data memorize | stored in the control part used for control of FIG. It is a table | surface figure which shows an experimental result.

  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 with reference to FIG.
In FIG. 1, 1 is a color copying machine as an image forming apparatus, 2 is a writing unit (exposure unit) that emits laser light based on input image information, and 20Y, 20M, 20C, and 20BK are colors (yellow, magenta, cyan, Black), 21 is a photosensitive drum as an image carrier accommodated in each of the process cartridges 20Y, 20M, 20C, and 20BK, 22 is a charging unit that charges the photosensitive drum 21, and 23Y, 23M. , 23C and 23BK are developing devices (developing units) for developing the electrostatic latent image formed on the photosensitive drum 21, and 24 is a first transfer unit for transferring the toner image formed on the photosensitive drum 21 to the intermediate transfer belt 27. 1 transfer bias roller (transfer portion), 25 is a cleaning device (cleaning device) that removes and collects untransferred toner on the photosensitive drum 21. Ring portion), show a.

  Reference numeral 27 denotes an intermediate transfer belt (transfer object) onto which toner images of a plurality of colors are superimposed, and 28 denotes a second transfer bias roller for transferring the toner image formed on the intermediate transfer belt 27 to the recording medium P, 29 is an intermediate transfer belt cleaning unit that collects untransferred toner on the intermediate transfer belt 27, 30 is a conveyance belt that conveys a recording medium P on which a four-color toner image is transferred, and 32Y, 32M, 32C, and 32BK are each A toner replenishing unit that replenishes each color toner to the developing devices 23Y, 23M, 23C, and 23BK, 51 a document conveying unit that conveys the document D to the document reading unit 55, and 55 a document reading unit that reads image information of the document D, 61 Indicates a paper feeding unit in which a recording medium P such as transfer paper is accommodated, and 66 indicates a fixing unit for fixing an unfixed image on the recording medium P.

Here, each of the process cartridges 20Y, 20M, 20C, and 20BK is obtained by integrating the photosensitive drum 21, the charging unit 22, and the cleaning device 25, respectively. The process cartridges 20Y, 20M, 20C, and 20BK are exchanged with respect to the apparatus main body 1 in a predetermined exchange cycle. Similarly, the developing devices 23Y, 23M, 23C, and 23BK are also exchanged with respect to the apparatus main body 1 in a predetermined exchange cycle.
Image formation of each color (yellow, magenta, cyan, black) is performed on the photosensitive drum 21 in each of the process cartridges 20Y, 20M, 20C, and 20BK.

Hereinafter, an operation during normal color image formation in the image forming apparatus will be described.
First, the document D is transported from the document table in the direction of the arrow in the drawing by the transport roller of the document transport unit 51 and placed on the contact glass 53 of the document reading unit 55. Then, the document reading unit 55 optically reads the image information of the document D placed on the contact glass 53.

  Specifically, the document reading unit 55 scans the image of the document D on the contact glass 53 while irradiating light emitted from the illumination lamp. Then, the light reflected by the document D is imaged on the color sensor via the mirror group and the lens. The color image information of the document D is read for each RGB (red, green, blue) color separation light by the color sensor, and then converted into an electrical image signal. Further, an image processing unit (not shown) performs color conversion processing, color correction processing, spatial frequency correction processing, and the like on the basis of RGB color separation image signals, so that yellow, magenta, cyan, and black are processed. Get color image information.

  Then, the image information of each color of yellow, magenta, cyan, and black is transmitted to the writing unit 2. The writing unit 2 emits laser light L (exposure light) based on the image information of each color toward the photosensitive drums 21 of the corresponding process cartridges 20Y, 20M, 20C, and 20BK, respectively.

On the other hand, the four photosensitive drums 21 rotate in the clockwise direction in FIG. 1 (and FIG. 2). First, the surface of the photosensitive drum 21 is uniformly charged at a position facing the charging unit 22 (a charging process). Thus, a charged potential is formed on the photosensitive drum 21. Thereafter, the surface of the charged photosensitive drum 21 reaches the irradiation position of each laser beam L.
In the writing unit 2, laser light corresponding to the image signal is emitted from the light source corresponding to each color. The laser light is incident on the polygon mirror 3 and reflected, and then passes through the lenses 4 and 5. The laser light after passing through the lenses 4 and 5 passes through different optical paths for each of the yellow, magenta, cyan, and black color components (this is an exposure process).

  The laser beam corresponding to the yellow component is reflected by the mirrors 6 to 8 and then irradiated onto the surface of the photosensitive drum 21 of the first process cartridge 20Y from the left side of the drawing. At this time, the yellow component laser light is scanned in the rotation axis direction (main scanning direction) of the photosensitive drum 21 by the polygon mirror 3 that rotates at high speed. Thus, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 21 charged by the charging unit 22.

  Similarly, the laser beam corresponding to the magenta component is reflected by the mirrors 9 to 11 and then irradiated to the surface of the photosensitive drum 21 of the second process cartridge 20M from the left side of the paper, thereby causing an electrostatic latent image corresponding to the magenta component. An image is formed. The cyan component laser light is reflected by the mirrors 12 to 14 and then irradiated on the surface of the photosensitive drum 21 of the third process cartridge 20C from the left side of the paper, thereby forming an electrostatic latent image of the cyan component. The black component laser light is reflected by the mirror 15 and then irradiated on the surface of the photosensitive drum 21 of the fourth process cartridge 20BK from the left side of the paper, thereby forming an electrostatic latent image of black component.

Thereafter, the surface of the photosensitive drum 21 on which the electrostatic latent images of the respective colors are formed reaches positions facing the developing devices 23Y, 23M, 23C, and 23BK, respectively. Then, the respective color toners are supplied from the developing devices 23Y, 23M, 23C, and 23BK onto the photosensitive drum 21, and the latent image on the photosensitive drum 21 is developed (this is a developing step).
Thereafter, the surface of the photosensitive drum 21 after the development process reaches a position facing the intermediate transfer belt 27 as a transfer target after passing through a position facing the photosensor 41 (see FIG. 2). . Here, a first transfer bias roller 24 as a transfer portion is installed at each facing position so as to contact the inner peripheral surface of the intermediate transfer belt 27. Then, at the position of the first transfer bias roller 24 (transfer portion), the images (toner images) of the respective colors formed on the photosensitive drum 21 are sequentially superimposed and transferred onto the intermediate transfer belt 27 (first image). It is a transfer process.)

Then, the surface of the photosensitive drum 21 after the first transfer process reaches a position facing the cleaning device 25. Then, the untransferred toner remaining on the photosensitive drum 21 is collected by the cleaning device 25 (this is a cleaning process).
Thereafter, the surface of the photosensitive drum 21 passes through a static elimination unit (not shown), and a series of image forming processes on the photosensitive drum 21 is completed.

On the other hand, the surface of the intermediate transfer belt 27 on which the images of the respective colors on the photosensitive drum 21 are transferred in an overlapping manner travels in the direction of the arrow in the drawing and reaches the position of the second transfer bias roller 28. Then, the full-color image on the intermediate transfer belt 27 is secondarily transferred onto the recording medium P at the position of the second transfer bias roller 28 (second transfer step).
Thereafter, the surface of the intermediate transfer belt 27 reaches the position of the intermediate transfer belt cleaning unit 29. Then, the untransferred toner on the intermediate transfer belt 27 is collected by the intermediate transfer belt cleaning unit 29, and a series of transfer processes on the intermediate transfer belt 27 is completed.

Here, the recording medium P at the position of the second transfer bias roller 28 is transported from the paper feeding unit 61 via the transport guide 63, the registration roller 64, and the like.
Specifically, the recording medium P fed by the paper feeding roller 62 from the paper feeding unit 61 that stores the recording medium P passes through the conveyance guide 63 and is guided to the registration roller 64. The recording medium P that has reached the registration roller 64 (timing roller) is conveyed toward the position of the second transfer bias roller 28 in synchronization with the toner image on the intermediate transfer belt 27.

Thereafter, the recording medium P on which the full-color image is transferred is guided to the fixing unit 66 by the conveyance belt 30. In the fixing unit 66, the color image is fixed on the recording medium P at the nip between the heating roller 67 and the pressure roller 68.
Then, the recording medium P after the fixing process is discharged as an output image by the paper discharge roller 69 to the outside of the apparatus main body 1, and a series of image forming processes is completed.

Next, the image forming unit of the image forming apparatus will be described in detail with reference to FIG.
FIG. 2 is a cross-sectional view showing the image forming unit. The four image forming units installed in the apparatus main body 1 have substantially the same structure except that the color of the toner T used in the image forming process is different. Therefore, the alphabet of reference numerals in the process cartridge, the developing device, and the toner replenishing unit. (Y, M, C, BK) is omitted for illustration.
As shown in FIG. 2, the process cartridge 20 mainly contains a photosensitive drum 21 as an image carrier, a charging unit 22, and a cleaning device 25 integrally in a case 26.

Here, the photosensitive drum 21 as an image bearing member is a negatively charged organic photosensitive member, in which a photosensitive layer or the like is provided on a drum-shaped conductive support. The photosensitive drum 21 rotates in a predetermined direction (clockwise in FIG. 2) with a toner image carried on the surface thereof. Although not shown, the photosensitive drum 21 is formed by sequentially laminating an undercoat layer as an insulating layer, a charge generation layer and a charge transport layer as a photosensitive layer, etc. on a conductive support as a base layer.
The charging unit 22 is a charging roller formed by covering an outer periphery of a conductive metal core with a medium resistance elastic layer. A predetermined voltage is applied to the charging unit 22 from a power supply unit (not shown), thereby uniformly charging the surface of the opposing photosensitive drum 21.

  The developing device (developing unit) 23 mainly faces the first conveying screw 23b via the developing roller 23a facing the photosensitive drum 21, the first conveying screw 23b facing the developing roller 23a, and the partition member 23e. The second conveying screw 23c and a doctor blade 23d facing the developing roller 23a are configured. The developing roller 23a includes a magnet that is fixed inside and forms a magnetic pole on the circumferential surface of the roller, and a sleeve that rotates around the magnet. A plurality of magnetic poles are formed on the developing roller 23a (sleeve) by the magnet, and the developer G is carried on the developing roller 23a.

In the developing device 23, a two-component developer G composed of carrier C and toner T is accommodated. In the first embodiment, as the toner T, a small particle diameter toner having a volume average particle diameter of 6 μm is used. Further, as the carrier C, a small particle size carrier having a volume average particle size of 35 μm is used.
The volume average particle size of the toner T and carrier C is typically measured by a coal counter type particle size distribution analyzer “Coulter Counter TA-2” (manufactured by Coulter Co.) or “Coulter Multisizer 2” (Coulter Company). Can be used.

  The cleaning device 25 includes a cleaning blade 25a (blade member) that comes into contact with the photosensitive drum 21 (image carrier), a brush-like roller 25b as a cleaning rotary member around which brush bristles that slide in contact with the photosensitive drum 21 are provided, a brush And a substantially plate-like flicker 25c (removal member) that is in sliding contact with the brush bristles of the roller 25b.

The cleaning blade 25a is made of a rubber material such as polyurethane rubber, silicone rubber, nitrile rubber, or chloroprene rubber, and is in contact with the surface of the photosensitive drum 21 at a predetermined angle and a predetermined pressure. By the cleaning blade 25 a, untransferred toner (toner that has not been transferred at the transfer portion) adhering to the photosensitive drum 21 is mechanically scraped and collected in the cleaning device 25. Here, as the deposits adhered to the photosensitive drum 21, in addition to the untransferred toner, paper dust generated from the recording medium P (paper), discharge products generated on the photosensitive drum 21 during discharge by the charging unit 22. And additives added to the toner.
In the first embodiment, the cleaning blade 25a is in contact with the rotation direction of the photosensitive drum 21 in the counter direction, but the photosensitive blade 21 is in the trailing direction with respect to the rotation direction of the photosensitive drum 21. The body drum 21 may be contacted.

The brush-like roller 25b as a cleaning rotator is a cored bar in which brush hairs having a length (bristles) in the range of 0.2 to 20 mm (preferably 0.5 to 10 mm) are planted on the base cloth. 2 is wound in a spiral shape, and rotates in the counterclockwise direction of FIG. 2 in a state where the bristle is in contact with the surface of the photosensitive drum 21.
The brush bristles of the brush-like roller 25b are made of resin fibers such as PET (polyethylene terephthalate), nylon, rayon, acrylic, vinylon, polyester, and vinyl chloride, and a conductivity-imparting agent such as carbon can be added as necessary. The brush hair preferably has a brush density of 1 to 50 (10,000 / inch ² ) and a brush resistance of 10 ⁻² to 10 ¹² (Ω · cm). In the first embodiment, the brush length is 5 (mm). ), With a brush density of 10 (10,000 / inch ² ) and a brush resistance of 10 ⁵ (Ω · cm). The brush-like roller 25b functions as a cleaning rotator that auxiliaryly scrapes off deposits such as untransferred toner that adhere to the photosensitive drum 21. Specifically, deposits such as untransferred toner adhering to the photosensitive drum 21 are scraped off by the brush roller 25b, and then removed by the flicker 25c and collected in the cleaning device 25.
It is also possible to configure such that the deposits such as untransferred toner collected in the cleaning device 25 are further transported by a transport member and collected in a waste toner collection container.

The image forming process described above will be described in more detail with reference to FIG.
The developing roller 23a rotates in the direction of the arrow in FIG. The developer G in the developing device 23 is supplied from the toner replenishing portion 32 to the toner replenishing port by the rotation of the first transport screw 23b and the second transport screw 23c arranged with the partition member 23e interposed therebetween. It circulates in the longitudinal direction while being agitated and mixed with the toner T replenished through 23f (in the direction perpendicular to the paper surface of FIG. 2).

  The toner T that is frictionally charged and adsorbed on the carrier C is carried on the developing roller 23a together with the carrier C. The developer G carried on the developing roller 23a then reaches the position of the doctor blade 23d. The developer G on the developing roller 23a is adjusted to an appropriate amount at the position of the doctor blade 23d, and then reaches a position facing the photosensitive drum 21 (developing area).

  Thereafter, in the development area, the toner T in the developer G adheres to the electrostatic latent image formed on the surface of the photosensitive drum 21. Specifically, the toner T is latently exposed by the electric field formed by the potential difference (development potential) between the latent image potential (exposure potential) of the image area irradiated with the laser light L and the development bias applied to the development roller 23a. Adhere to the image.

  Thereafter, most of the toner T adhering to the photosensitive drum 21 in the developing process is transferred onto the intermediate transfer belt 27. Then, the untransferred toner T remaining on the photosensitive drum 21 is cleaned by the cleaning blade 25a and the brush-like roller 25b (cleaning rotator) and collected in the cleaning device 25.

  Here, a toner replenishing unit 32 provided in the apparatus main body 1 includes a toner bottle 33 configured to be replaceable, and a toner hopper unit 34 that holds and rotates the toner bottle 33 and replenishes the developing device 23 with new toner T. And is composed of. Also, a new toner T (any one of yellow, magenta, cyan, and black) is accommodated in the toner bottle 33. In addition, a spiral protrusion is formed on the inner peripheral surface of the toner bottle 33.

The new toner T in the toner bottle 33 is appropriately replenished into the developing device 23 from the toner replenishing port 23f as the toner T (existing toner) in the developing device 23 is consumed. . The toner T in the developing device 23 is consumed indirectly or directly by the reflective photosensor 41 facing the photosensitive drum 21 and the magnetic sensor 40 installed below the second conveying screw 23c of the developing device 23. Detected.
In the first embodiment, the toner density (TC) is controlled to be within a predetermined range. Specifically, toner replenishment is performed so that the detection results of the magnetic sensor 40 and the reflection type photosensor 41 have an output value corresponding to the above-described toner density range (the ratio of the toner T in the developer G). The toner is supplied from the unit 32 to the developing device 23 through the toner supply port 23f.

Hereinafter, characteristic control performed by the image forming apparatus 1 according to the first embodiment will be described in detail.
As described above with reference to FIG. 2 and the like, the image forming apparatus 1 according to the present embodiment has a predetermined direction (counterclockwise in FIG. 2) in contact with the surface of the photosensitive drum 21 (image carrier). A brush-like roller 25b is installed as a cleaning rotator for cleaning the toner on the photosensitive drum 21 that has not been transferred at the position of the transfer portion (first transfer bias roller 24). Yes.
Referring to FIG. 2, the image forming apparatus 1 is provided with a drive motor 50 as a drive unit that rotationally drives the photosensitive drum 21 and the brush-like roller 25 b (cleaning rotator). Although illustration is omitted, a coupling that fits into a coupling formed on a flange on one end side in the rotation axis direction of the photosensitive drum 21 is provided on the driving shaft of the driving motor 50. Further, the gear formed on the flange on the other end side in the rotation axis direction of the photosensitive drum 21 is configured to mesh with the gear installed on the shaft portion of the brush-like roller 25b. That is, the drive motor 50, the coupling, and the gear function as a drive unit that rotationally drives the photosensitive drum 21 and the brush-like roller 25b.

  The driving means in the first embodiment is one driving source (the driving motor 50) without variably controlling the number of rotations and the direction of rotation of the photosensitive drum 21 and the brush roller 25b. Thus, the photosensitive drum 21 and the brush-like roller 25b are driven at the same timing. With such a configuration, the image forming apparatus 1 can be compared with the case where the photosensitive drum 21 and the brush-like roller 25b are driven by different driving units to variably control the rotation speed and the rotation direction of the brush-like roller 25b. It is possible to reduce the size and cost.

Further, in the first embodiment, the brush-like roller 25 b (cleaning rotator) is configured to rotate in a direction opposite to the rotation direction of the photosensitive drum 21, and in a contact position with the photosensitive drum 21. The linear velocity ratio with respect to the photosensitive drum 21 is configured to be in the range of 1.0 to 2.0. Specifically, in the first embodiment, the linear velocity of the photosensitive drum 21 is about 420 mm / second, the linear velocity of the brush-like roller 25b is about 700 mm / second, and both the members 21 and 25b are It is set to rotate in the accompanying direction.
As described above, the brush-like roller 25b is not slidably brought into contact with the photosensitive drum 21 with a large linear speed difference, so that the photosensitive member is compared with the case where the brush-like roller 25b is slidably brought into contact with the photosensitive drum 21 with a large linear speed difference. It is possible to reduce a problem that the wear of the surface of the drum 21 is promoted. For this reason, the surface of the photoconductive drum 21 is worn, the latent image is disturbed, and halftone density unevenness occurs in the output image, or background stains occur on the photoconductive drum 21. can do.

  In the first embodiment, after a job command is input to the image forming apparatus 1 in the control unit 56 (CPU, RAM, ROM, etc.) serving as calculation means, A toner input amount (cleaning load) per unit time input to the brush-like roller 25b (cleaning rotator) in one job involved is obtained (expected). Based on the result of the calculation means (the toner input amount per unit time input to the brush roller 25b in one job), the photosensitive drum 21 is driven by the drive motor 50 (drive means) in the one job. And the time until the drive of the brush roller 25b is stopped is variable.

The “job command” is a command related to a series of image forming operations (image forming operations per job) by an operator who operates the image forming apparatus 1, and includes the size of the recording medium P to be passed and the paper passing rate. The number of copies (number of copies), image magnification, and the like are input from the operation panel 57. “One job” refers to a series of image forming operations from when the operation of the image forming apparatus 1 is started to when the operation is stopped, and when the number of sheets to be passed is set in the job command. (Continuous paper feeding) is an operation from the start of the image forming operation related to the first recording medium P to the end of the image forming operation related to the last recording medium P.
In the first embodiment, since the copying machine as the image forming apparatus 1 is used, the “job command” is sent to the control unit 56 via the operation panel 57 (operation unit) installed on the exterior of the apparatus body 1. Will be sent to. On the other hand, when a printer as the image forming apparatus 1 is used, a “job command” is input from a personal computer or the like connected to the apparatus main body 1 and sent to the control unit 56.

Specifically, the calculation means (control unit 56) calculates “the amount of toner input per unit time input to the brush roller 25b in one job” by the following procedure.
First, based on the “original image area” of the original D and the “image magnification” set by the job command, the “toner image area” of the toner image formed on the photosensitive drum 21 is calculated.
Here, the “document image area” is a total area occupied by images other than the background portion in the document D, and can be calculated based on information optically detected by the document reading unit 55. The “image magnification” is the magnification (enlargement, equal magnification, or reduction) of the image on the recording medium P (or the photosensitive drum 21) with respect to the original image. Specifically, the “toner image area” is obtained by the following equation.
“Toner image area (mm ² )” = “Original image area (mm ² )” × “Image magnification (%)” / 100
In the first embodiment, the “toner image area” is obtained based on the “original image area” and the “image magnification”. However, information on the writing unit 2 that forms a latent image on the photosensitive drum 21 ( The “toner image area” can also be calculated based on the write duty. This is particularly useful when a printer as the image forming apparatus 1 is used.

Thereafter, from the calculated “toner image area” and the “number of sheets to be passed” set by the job command, the “toner consumption per job” is obtained, and then the brush roller 25b (cleaning device 25). "Total amount of toner per job" is calculated.
Specifically, “toner consumption per job” is obtained by the following equation.
“Toner consumption per job (mg)” = “toner image area (mm ² )” × “area density of toner image on the photosensitive drum (mg / mm ² )” × “number of sheets passed (sheets)”
Here, the “surface density of the toner image” is stored in the ROM of the control unit 56 as a fixed value of 0.007 (mg / mm ² ) based on experiments performed in advance.
The “total amount of toner per job” is obtained by the following equation.
“Total amount of toner per job (mg)” = “Toner consumption per job (mg)” × 0.2
Here, “0.2” in the above equation is set as a fixed value on the basis of the transfer rate of the toner image from the photosensitive drum 21 to the intermediate transfer belt 27 obtained in an experiment conducted in advance.

Then, the photosensitive drum 21 (and the brush-like roller 25b) is moved by the driving motor 50 (driving means) based on the “recording medium size” and “number of sheets to be passed” set by the job command. The “total driving time” for driving is calculated.
Specifically, the “total driving time” refers to the time from when the driving of the photosensitive drum 21 is started until the recording medium P reaches the position of the second transfer bias roller 28 as T1 (seconds). The time from the passage of the second transfer bias roller 28 to the stop of the driving of the photosensitive drum 21 is T2 (seconds), and the time until the driving of the photosensitive drum 21 is stopped (driving extension time). Is T3 (seconds).
“Total drive time (seconds)” = T1 (seconds) + {“Recording medium size (conveyance direction size)” × “Number of sheets passed” + “Conveyance interval between recording medium and recording medium (between sheets) × (“ Number of sheets passed "-1)"} / "Process linear velocity (mm / sec)" + T2 (sec) + T3 (sec)
Here, in the first embodiment, the “recording medium size” is based on the information set by the job command (information on the recording medium P input to the operation panel 57). It may be based on information directly detected by the detection unit 58 (size detection sensor).
In the first exemplary embodiment, the image forming apparatus 1 is provided with a plurality of image forming units and the intermediate transfer belt 27 installed. The photosensitive drum 21 is driven while the intermediate transfer belt 27 is driven. However, the image forming apparatus is provided with one image forming unit (the toner image formed on the photosensitive drum is directly transferred onto the recording medium by the transfer unit). In the above equation, T1 (second) is the time from the start of driving the photosensitive drum until the recording medium P reaches the position of the photosensitive drum, and T2 (second) is the recording medium. This is the time from when P passes through the position of the photosensitive drum until the driving of the photosensitive drum is stopped.

Finally, the “toner input amount per unit time (cleaning load)” is calculated from the calculated “total toner amount per job” and “total driving time”.
Specifically, the “toner input amount per unit time (cleaning load)” is obtained by the following equation.
“Toner input amount per unit time (mg / second)” = “total amount of toner per job (mg)” / “total driving time (seconds)”

If the “toner input amount per unit time (cleaning load)” exceeds a predetermined value, the drive motor 50 stops driving the photosensitive drum 21 and the brush roller 25b in one job. The time is extended, and finally, the “toner input amount per unit time (cleaning load)” in one job is controlled to be a predetermined value or less.
Specifically, in the first embodiment, when the “toner input amount per unit time (cleaning load)” exceeds 33 mg / second (predetermined value), the above-described drive extension time T3 (photosensitive drum 21 and It is controlled so that the “toner input amount per unit time (cleaning load)” is 33 mg / second (predetermined value) or less. The details will be described in detail with reference to the flowchart of FIG.

As described above, in the first embodiment, even if the linear velocity of the brush roller 25b is set to be relatively low in order to reduce damage to the photosensitive drum 21, the “toner input amount per unit time” is finally set. The time until the driving of the photosensitive drum 21 and the brush roller 25b is stopped is adjusted so that the “cleaning load” does not increase. Therefore, many images with a high image area ratio are formed, and a large amount of deposits such as toner additives adhere to the surface of the photosensitive drum 21, and the toner additives and the like are caused by the brush roller 25b (cleaning device 25). It is possible to surely reduce a problem that the adhering matter cannot be sufficiently removed and collected. That is, when it is determined that a large amount of deposits such as toner additives adhere to the surface of the photosensitive drum 21, the driving time of the brush roller 25b (photosensitive drum 21) is determined according to the situation. The cleaning time is extended. Therefore, the problem that an abnormal image such as a blank image is generated due to the toner being deposited and fixed on the photosensitive drum 21 where the toner additive or the like is attached is reduced.
In other words, the cleaning device 25 per unit time is extended by extending the driving time of the photosensitive drum 21 and the brush-like roller 25b after the last toner image is transferred to the intermediate transfer belt 27 (recording medium P). Therefore, the image forming apparatus 1 is not complicated and the cost is increased, so that an abnormal image due to early wear of the photosensitive drum 21 and toner fixation on the photosensitive drum 21 can be achieved. Can be prevented.

Hereinafter, a specific flow in such characteristic control will be described with reference to FIG.
First, when the image information of the document D is read by the document reading unit 55, the image area of the document D (“document image area”) is detected at the same time (step S1).
Thereafter, the “toner image area” is calculated based on the detection result of the “original image area” in step S1 and the “image magnification” set by the operator (step S2). The “toner image area” calculated here is recorded in the RAM of the control unit 56.
Then, “toner consumption per job” is calculated based on the “number of sheets to be passed” set by the operator (step S3). The “toner consumption per job” calculated here is also recorded in the RAM of the control unit 56.
Further, based on the calculated “toner consumption per job”, the toner amount input to the cleaning device (“total toner amount per job”) is calculated (step S4). This “total amount of toner per job” is also recorded in the RAM of the control unit 56.

Further, the photosensitive member driving time (“total driving time”) is calculated (step S5), and the calculation result is recorded in the RAM of the control unit 56. In the above-described “total driving time” equation, the time T1 and the time T2 are obtained in advance through experiments and are stored in the ROM of the control unit 56. In addition, information such as the sizes of various recording media P in the transport direction and the interval between sheets is also stored in the ROM. The time T3 (drive extension time) is input as 0 seconds as an initial value, and is varied according to the “toner input amount per unit time (cleaning load)” calculated in the next step S6.
Thereafter, “toner input amount per unit time (cleaning load)” is calculated based on the calculation result of step S4 and the calculation result of step S5 (step S6), and the calculation result is recorded in the RAM.
Then, it is determined whether the “toner input amount per unit time (cleaning load)” obtained in step S6 exceeds a predetermined value (33 mg / sec) (step S7). As a result, when the cleaning load exceeds a predetermined value, 0.2 seconds is added to the drive extension time T3 (step S14), and the flow of steps S5 to S7 and S14 is continued until the cleaning load becomes equal to or less than the predetermined value. Repeated. That is, the drive extension time T3 is calculated by the following equation, and the calculation result is recorded in the RAM.
T3 (seconds) = 0.2 (seconds) × [number of times step S14 is executed]

Thereafter, driving of the photosensitive drum 21 and the brush roller 25b is started by the drive motor 50 (step S8), and execution of a series of image forming operations (image forming operations) is started (step S9). In step S10, it is determined whether a series of image forming operations has reached the set number of sheets to be passed, and the flow of steps S9 and S10 is repeated until the series of image forming operations reaches the set number of sheets to be passed.
Then, after the set number of sheets has been passed, it is determined whether the drive extension time T3 recorded in the RAM is 0 (seconds) (step S11). If the drive extension time T3 is 0, the drive of the photosensitive drum 21 and the brush roller 25b by the drive motor 50 is stopped without extending the drive time (step S12). On the other hand, if the drive extension time T3 is not 0, the drive time is extended by the extension time T3 (step S15), and then the photosensitive drum 21 and the brush roller 25b are driven by the drive motor 50. Stop (step S12).
Finally, the drive extension time T3 recorded in the RAM is returned to the initial value (0 seconds) (step S13), and this flow ends.

  As described above, according to the first embodiment, after a job command is input to the image forming apparatus 1, “toner per unit time” input to the brush-like roller 25 b (cleaning rotator) in one job. Based on the result, the time T3 until the drive of the photosensitive drum 21 (image carrier) and the brush roller 25b is stopped is varied. Thus, the adhering material such as the untransferred toner and the toner additive adhering to the surface of the photosensitive drum 21 is removed from the brush-like roller 25b (cleaning device 25) without variably controlling the rotation speed and direction of the brush-like roller 25b. ) Can be sufficiently removed, and the problem that the abrasion of the surface of the photosensitive drum 21 is promoted by the sliding contact of the brush-like roller 25b can be reduced.

Embodiment 2. FIG.
A second embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 4 is a flowchart showing the control performed by the image forming apparatus 1 according to the second embodiment, and FIG. 5 is a flowchart showing a subroutine in the control of FIG. FIG. 6 is a table showing an example of data stored in the control unit 56 used in the control of FIG.
In the control according to the second embodiment, when the number of sheets of one job set by the job command exceeds a predetermined set value, the number of sheets to be passed becomes equal to or less than the set value. This is different from the first embodiment in that one job is divided into a series of divided jobs, and the toner input amount per unit time is controlled to be a predetermined value or less for each divided job.

In the image forming apparatus 1 according to the second embodiment, first, the number of passing sheets of one job set by the job command is a predetermined setting value (“cleaning load calculation number”, which is 100 in the second embodiment). If the number of sheets passed is less than the set value, one job is divided into a series of divided jobs and set.
For example, when the number of sheets for one job is set to 250, the number of sheets for the first divided job is 100, the number of sheets for the second divided job is 100, and the number of sheets for the third divided job is passed. The number of sheets is set to 50 sheets.
The “division job” is obtained by dividing one job, and the division motor and the division job are continuously driven by the drive motor 50 and the like without any breaks.

Then, the calculation means (CPU of the control unit 56) obtains “toner input amount per unit time (cleaning load)” input to the cleaning rotator for each of the divided jobs divided into a plurality of jobs. Then, based on the result of the calculation means, for each divided job divided into a plurality of times, the time until the driving of the photosensitive drum 21 and the brush roller 25b by the drive motor 50 in the divided job is variable. To do.
That is, the drive extension time T3 of the divided job performed in advance is reflected between the divided jobs, and the start of the next divided job is controlled to be delayed by that amount. Sometimes.

Specifically, first, the calculation unit calculates the photosensitive drum 21 based on the “original image area” of the original and the “image magnification” set by the job command (or based on the information of the writing unit 2). The “toner image area” of the toner image formed above is calculated for each of the divided jobs divided into a plurality.
Then, based on the calculated “toner image area” and the “number of sheets to be passed” set in the job command, the “toner consumption amount for each divided job” is input to the brush-like roller 25b. Calculate the total amount of toner for each job.
The calculated “total amount of toner for each divided job” and the “total drive” for driving the photosensitive drum 21 (or the brush-like roller 25b) by the drive motor 50 (driving means) for each of the divided jobs divided into a plurality of divided jobs. From “Time”, the “toner input amount per unit time for each divided job” is calculated.

  When the “toner input amount per unit time for each divided job” exceeds a predetermined value (33 mg / second in the second embodiment), the drive motor 50 in the divided job is set. As a result, the time T3 until the driving of the photosensitive drum 21 and the brush roller 25b is completed is extended, and the “toner input amount per unit time (cleaning load)” in the divided job is finally less than a predetermined value. It is controlled to become.

  As described above, in the second embodiment, the toner input amount input to the brush roller 25b (cleaning device 25) per unit time is calculated every predetermined number of sheets, and the calculation result of the toner input amount is a predetermined value. In the state where the image forming operation is interrupted, the driving time of the photosensitive drum 21 and the brush roller 25b is extended so that the toner input amount is not more than a predetermined value when the image forming operation is interrupted. Even when continuous printing with a large area ratio is performed, toner fixation on the photosensitive drum 21 can be prevented.

Hereinafter, a specific flow in such characteristic control will be described with reference to FIGS.
First, when the image information of the document D is read by the document reading unit 55, the image area of the document D (“document image area”) is detected at the same time (step S21).
Thereafter, information such as “the number of sheets to be passed” set by the operator is stored in the RAM (step S22). Then, based on the information and the “setting value (cleaning load calculation number)” stored in the RAM in advance, the condition of one job set by the operator is divided into a plurality of conditions (divided jobs). Saved in. For example, as shown in FIG. 6, conditions 1 to N are set as a divided job divided into a plurality of jobs. The number of sheets to be passed in each condition (each divided job) at this time is “set value (cleaning load calculation number)”, which is 100 sheets (an initial value that can be variably set). It is set to be the following number.
In step S23, the drive extension time T3 is calculated and recorded in the RAM for each divided job (each condition shown in FIG. 6) based on the subroutine shown in FIG. The calculation method of the drive extension time T3 for each divided job at this time is almost the same as the calculation method of the drive extension time T3 for each job described in the first embodiment. Each calculation result used in the calculation process is recorded in the RAM as shown in the column “image forming apparatus calculation result” in FIG.

Thereafter, condition 1 (first divided job) stored in the RAM is read as an image forming condition (image forming condition) (step S24), and the photosensitive drum 21 and the brush-like roller are read based on the condition. The driving of 25b is started (step S25). Then, a series of image forming operations (image forming operations) related to the divided job is started (step S26). In step S27, it is determined whether a series of image forming operations related to the divided job has reached the set number of sheets to be passed, and the flow of steps S26 and S27 is repeated until the set of image forming operations reaches the set number of sheets to be passed. It is.
Then, it is determined whether the driving extension time T3 (the driving extension time T3 in the divided job) recorded in the RAM is 0 after the passing of the number of sheets set in the divided job is completed. (Step S28). When the drive extension time T3 is 0, the drive of the photosensitive drum 21 and the brush-like roller 25b by the drive motor 50 is finished without extending the drive time, and the next condition (divided job) is stored in the RAM. It is determined whether it is stored (step S29). On the other hand, if the drive extension time T3 is not 0 in step S28, the drive time is extended by the extension time T3 (step S33), and then the photosensitive drum 21 and the brush roller 25b by the drive motor 50 are used. Is finished, and it is determined whether or not the next condition (divided job) is stored in the RAM (step S29).

As a result, if it is determined in step S29 that the next condition (division job) is stored in the RAM, the condition (division job) is read from the RAM (step S32), and based on the condition. The flow of steps S26 to S29 and S33 is repeated. Such a flow is performed until all conditions (divided jobs) stored in the RAM are executed.
Then, after all divided jobs (one job) are completed, the driving of the photosensitive drum 21 and the brush-like roller 25b by the drive motor 50 is stopped (step S30).
Finally, all the conditions (divided jobs) recorded in the RAM are returned to the initial values (step S31), and this flow is finished.

Hereinafter, the subroutine executed in step S23 of FIG. 4 will be briefly described with reference to FIG.
First, the “toner image area” is calculated based on the detection result of the “original image area” detected in step S21 of FIG. 4 and the “image magnification” set by the operator (step S101). Based on the “number of sheets to be passed” set by the operator, “toner consumption per divided job” is calculated (step S102).
Further, based on the calculated “toner consumption per divided job”, a toner amount (“total toner amount per divided job”) input to the cleaning device is calculated (step S103). Further, the photosensitive member driving time (“total driving time”) for each divided job is calculated (step S104).
Then, based on the calculation result of step S103 and the calculation result of step S104, the “toner input amount (cleaning load) per unit time in the divided job” is calculated (step S105).
Then, it is determined whether the “toner input amount per unit time (cleaning load) in the divided job” obtained in step S105 exceeds a predetermined value (33 mg / second) (step S106). As a result, when the cleaning load exceeds a predetermined value, 0.2 seconds is added to the drive extension time T3 (step S108), and the flow of steps S104 to S106 and S108 is continued until the cleaning load becomes equal to or less than the predetermined value. Repeated.
Then, the drive extension time T3 (= 0.2 (seconds) × [number of times of execution of step S108]) calculated in the divided job is recorded in the RAM (step S107), and this flow is finished.
Such a flow is executed for all divided jobs.

  As described above, according to the second embodiment, after a job command is input to the image forming apparatus 1, “toner per unit time” input to the brush-like roller 25 b (cleaning rotator) in one job. The “input amount” is obtained for each divided job, and based on the result, the time T3 until the driving of the photosensitive drum 21 (image carrier) and the brush roller 25b in one job is completed is variable for each divided job. doing. Thus, the adhering material such as the untransferred toner and the toner additive adhering to the surface of the photosensitive drum 21 is removed from the brush-like roller 25b (cleaning device 25) without variably controlling the rotation speed and direction of the brush-like roller 25b. ) Can be sufficiently removed, and the problem that the abrasion of the surface of the photosensitive drum 21 is promoted by the sliding contact of the brush-like roller 25b can be reduced.

Experimental result.
With reference to FIG. 7, an experiment conducted by the inventor in order to confirm the effect of the present invention will be described.
FIG. 7 shows experimental results in which the relationship between the number of sheets to be passed and the image quality (“image disorder” and “white spot”) is confirmed using the image forming apparatus 1 shown in FIG. In the experiment, an A4 size recording medium P was passed in the transverse feed direction with one continuous sheet passing (the number of passing sheets per job) being 100, and the image area on each recording medium P was measured. An image with a rate of 30% is formed, and the image quality is evaluated every 50K sheets (50000 sheets). The driving of the photosensitive drum 21 and the brush-like roller 25b is stopped for a certain time after the image forming operation is completed (after the end of one job) every 100 continuous sheets.
In FIG. 7, “image disorder” is an abnormal image generated due to wear of the surface of the photosensitive drum 21, and “white spot” is white spot in the image portion due to toner fixing on the surface of the photosensitive drum 21. is there. In FIG. 7, “◯” indicates that a high-quality image was obtained without occurrence of image disturbance or whiteout, and “Δ” indicates that image distortion or whiteout was slightly observed, “X” indicates that an unacceptable image distortion or white spot is observed.

In FIG. 7, the experimental condition of “Comparative Example 1” is that the linear velocity of the photosensitive drum 21 is 420 mm / second, the linear velocity of the brush roller 25b is 700 mm / second, and the difference between the linear velocities of both the members 21 and 25b. It is set to 280 mm / sec. In Comparative Example 1, the “toner input amount per job (cleaning load)” is 35 mg / second. From the experimental results shown in FIG. 7, in Comparative Example 1, even when 300K image forming operations are performed, image disturbance due to wear on the photoreceptor surface does not occur, but white spots start to occur when the number of sheets to be passed is about 50K. It can be seen that a large amount of white spots occur after 150K sheets.
The experimental conditions of “Comparative Example 2” are as follows: the linear velocity of the photosensitive drum 21 is 420 mm / second, the linear velocity of the brush roller 25b is 850 mm / second, the difference between the linear velocity of both the members 21 and 25b is 430 mm / second, Is set. In Comparative Example 2, “toner input amount per job (cleaning load)” is 35 mg / second. From the experimental results of FIG. 7, in Comparative Example 2, white spots do not occur even when 300K sheets are printed, but image distortion starts to occur when the number of sheets to be passed is about 150K, and an unacceptable image after 300K sheets. It turns out that disorder occurs. In order to prevent image disturbance, it is necessary to reduce the linear velocity difference between the two members 21 and 25b to be smaller than the condition of Comparative Example 2 to suppress the surface wear of the photosensitive drum 21.
The experimental conditions of “Example” are as follows: the linear velocity of the photosensitive drum 21 is 420 mm / second, the linear velocity of the brush roller 25b is 700 mm / second, and the difference between the linear velocities of both members 21 and 25b is 280 mm / second. (The linear velocity is the same as in Comparative Example 1). However, in the embodiment, the drive extension time T3 after the end of one job (after the end of the passing of the 100th recording medium P) is set to 5 seconds. That is, in the embodiment, the time until the driving of the photosensitive drum 21 and the brush-like roller 25b in one job is set longer than that in the first comparative example by 5 seconds. The “toner input amount per job (cleaning load)” in the embodiment is 33 mg / second. From the experimental results shown in FIG. 7, it can be seen that, in the embodiment, even when 300K sheets are printed, image distortion and white spots do not occur.

In each of the above-described embodiments, the cleaning device 25 and the charging unit 22 are integrated with the photosensitive drum 21 to form the process cartridge 20 so as to reduce the size of the image forming unit and improve maintenance workability. Yes.
On the other hand, the cleaning device 25, the charging unit 22, and the photosensitive drum 21 may be configured so as to be replaceable in the apparatus main body 1 as a single unit without being a component of the process cartridge. Further, the developing device 23 can be a constituent member of the process cartridge. In these cases, the same effects as those of the above embodiments can be obtained.
In the present application, “process cartridge” means a charging device (charging unit) for charging an image carrier, a developing device (developing unit) for developing a latent image formed on the image carrier, and an image carrier. It is defined as a unit in which at least one of the cleaning devices (cleaning unit) for cleaning the top and the image carrier are integrated and installed detachably with respect to the image forming apparatus main body.

In each of the above embodiments, the present invention is applied to the image forming apparatus on which the two-component developing type developing device 23 using the two-component developer is mounted. However, the one-component developing method using the one-component developer is used. Naturally, the present invention can also be applied to an image forming apparatus on which the developing device 23 is mounted.
In each of the above embodiments, the present invention is applied to a color image forming apparatus in which a plurality of image forming units are arranged in parallel so as to face the intermediate transfer belt 27. However, one image forming unit is a transfer unit. Of course, the present invention can also be applied to a monochrome image forming apparatus installed to face the (transfer member).
In each of the above embodiments, the present invention is applied to the cleaning rotating body 25b that cleans the surface of the photosensitive drum 21 as an image carrier. However, the photosensitive belt, the intermediate transfer belt, the intermediate transfer drum, etc. Naturally, the present invention can also be applied to a cleaning rotator for cleaning the surface of an image carrier.
Furthermore, in each of the above embodiments, the present invention is applied to the image forming apparatus 1 that uses the brush-like roller 25b as a cleaning rotator. The present invention can also be applied to an image forming apparatus using the formed cleaning rotator.
In these cases, the same effects as in 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.

1 image forming apparatus (image forming apparatus main body),
21 Photosensitive drum (image carrier),
23, 23Y, 23M, 23C, 23BK Developing device (developing unit),
25 Cleaning device (cleaning part),
25a Cleaning blade,
25b Brush-like roller (cleaning rotating body),
25c Flicker,
50 drive motor (drive means, drive source),
56 control unit (calculation means),
G Two-component developer (developer), T toner, C carrier.

Japanese Patent No. 3794515 JP 2006-58694 A

Claims (9)

An image carrier that rotates in a predetermined direction while carrying a toner image;
A cleaning rotator that rotates in a predetermined direction in contact with the surface of the image carrier and cleans the toner on the image carrier that has not been transferred at the position of the transfer portion;
Drive means for rotationally driving the image carrier and the cleaning rotator;
Calculating means for obtaining a toner input amount per unit time input to the cleaning rotator in one job after a job command is input to the apparatus;
With
An image forming apparatus characterized in that, based on the result of the calculating means, the time until the driving means stops driving the image carrier and the cleaning rotator in the one job is varied. The calculating means includes
It is formed on the image carrier based on the original image area of the original and the image magnification set by the job command, or based on information of a writing unit that forms a latent image on the image carrier. Calculate the toner image area of the toner image,
The total amount of toner per job input to the cleaning rotating body is calculated from the toner consumption amount per job determined based on the calculated toner image area and the number of sheets passed by the job command. And
2. The toner input amount per unit time is calculated from the calculated total toner amount per job and a total driving time for driving the image carrier by the driving unit. Image forming apparatus.   When the toner input amount per unit time exceeds a predetermined value, the time until the drive of the image carrier and the cleaning rotator is stopped by the driving unit in the one job is extended, 3. The image forming apparatus according to claim 1, wherein the toner input amount per unit time in one job is finally controlled to be equal to or less than the predetermined value. 4. When the number of sheets of one job set by the job command exceeds a predetermined set value, the one job is divided into a series of divisions so that the number of sheets to be passed is equal to or less than the set value. Divide multiple settings into jobs,
The calculation means obtains a toner input amount per unit time input to the cleaning rotator for each of the divided jobs divided into the plurality,
Based on the result of the calculation means, for each of the divided jobs divided into a plurality of times, the time until the driving of the image carrier and the cleaning rotator is finished by the driving means in the divided job is varied. The image forming apparatus according to claim 1. The calculating means includes
It is formed on the image carrier based on the original image area of the original and the image magnification set by the job command, or based on information of a writing unit that forms a latent image on the image carrier. A toner image area of the toner image is calculated for each of the divided jobs divided into the plurality of divided jobs;
Based on the calculated toner image area and the toner consumption amount for each divided job determined based on the number of sheets to be passed set by the job command, the total toner amount for each divided job input to the cleaning rotating body. To calculate
Toner input per unit time for each divided job from the calculated total toner amount for each divided job and the total driving time for driving the image carrier by the driving unit for each of the divided jobs divided into a plurality of divided jobs The image forming apparatus according to claim 4, wherein the amount is calculated.   When the amount of toner input per unit time for each divided job exceeds a predetermined value, the time until the driving of the image carrier and the cleaning rotating body is completed by the driving unit in the divided job is determined. 6. The image forming apparatus according to claim 4, wherein the image forming apparatus is extended and controlled so that a toner input amount per unit time in the divided job finally becomes equal to or less than the predetermined value.   The drive means controls the image carrier and the cleaning rotator at the same timing by a single drive source without variably controlling the number of rotations and the direction of rotation of the image carrier and the cleaning rotator. The image forming apparatus according to any one of claims 1 to 6, wherein the image forming apparatus is driven by the motor.   8. The image forming apparatus according to claim 1, wherein the cleaning rotator is a brush-like roller having brush bristles that are in sliding contact with the image carrier.   The cleaning rotator is configured to rotate in a direction opposite to the rotation direction of the image carrier, and a linear velocity ratio with respect to the image carrier at a position in contact with the image carrier is 1.0 to 2. 9. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured to fall within a range of 0.0.

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