JP2014142472A - Image forming apparatus and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus and program capable of reducing a wear step of a photoreceptor.SOLUTION: An image forming apparatus is configured: to control latent image forming means to divide the surface of a photoreceptor in a direction intersecting with a direction of rotation into a plurality of areas B1 to B5, take, as a target area, an area other than an area in which an integrated value of image information on each of the plurality of areas B1 to B5 is equal to or lower than a predetermined threshold in a predetermined range along the direction of rotation, and form an electrostatic latent image at a portion other than a portion corresponding to the target area in a non-image formation area Rng3 that is subsequent to the predetermined range on the photoreceptor; and to control developing means so that fatty acid metal salt particles separated from a toner are supplied to a portion in the non-image formation area Rng3 where the electrostatic latent image is not formed.

Description

  The present invention relates to an image forming apparatus and a program.

  Patent Document 1 discloses an image forming apparatus that forms an image on a recording material, an image carrier, a unit that forms an electrostatic latent image on the image carrier, and the electrostatic latent image at a developing position. And a developing means for developing using a developer containing an external additive having a charge polarity opposite to that of the toner, a cleaning blade for cleaning the image carrier, and a bias control for controlling a bias applied to the developing means The bias control means according to the information relating to the length of the interval area between the electrostatic latent images when a plurality of pages of electrostatic latent images pass through the development position. An image forming apparatus is disclosed in which a bias to be applied to the developing unit when an interval region between electrostatic latent images passes through the developing position is set.

JP 2004-004685 A

  An object of the present invention is to provide an image forming apparatus and a program capable of reducing the wear level difference of the photosensitive member.

  In order to achieve the above object, an image device according to claim 1 includes a latent image forming unit that exposes a surface of a charged and rotating image carrier to form an electrostatic latent image, and fatty acid metal salt particles. Developing means for developing the electrostatic latent image with a developer containing toner externally added to form a toner image on the image carrier, and the image carrier after the toner image is transferred Cleaning means for cleaning the image carrier in contact with the image carrier, and dividing the surface of the image carrier into a plurality of regions in a direction crossing the rotation direction, and the plurality of the plurality of regions within a predetermined range along the rotation direction. A region other than a region where the integrated value of the image information for each region is equal to or less than a predetermined threshold is set as a target region, and the target region of the non-image forming region after the predetermined range on the image carrier is set as the target region. Forming an electrostatic latent image on the part other than the corresponding part And controlling the developing unit so that the fatty acid metal salt particles separated from the toner are supplied to a portion of the non-image forming area where no electrostatic latent image is formed. Control means.

  The invention according to claim 2 is the invention according to claim 1, wherein the control means sets, as the target area, an area in which the integrated value is equal to or greater than a threshold value greater than the predetermined threshold, The latent image forming means is controlled to form an electrostatic latent image on a portion of the image carrier other than the portion corresponding to the target region in the non-image forming region after the predetermined range.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the control means is provided on a portion other than a portion corresponding to the target region of the non-image forming region on the image carrier. The electrostatic latent image is developed to form a toner image, and the developing means is controlled so that fatty acid metal salt particles separated from the toner are supplied to the target area.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the control means is a part other than the part corresponding to the target area of the image information and the non-image forming area. And combining the image information indicating the electrostatic latent image to be formed into the combined image information, and controlling the latent image forming means so that the electrostatic latent image is formed based on the combined image information, The developing means is controlled so that fatty acid metal salt particles separated from toner are supplied to the target area of the non-image forming area.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the predetermined range is determined by the number of rotations of the image carrier accompanying image formation based on image information. It prescribes.

  Further, the invention according to claim 6 is the invention according to any one of claims 1 to 4, wherein the predetermined range is defined by the number of recording media on which an image is formed based on image information. It is.

  On the other hand, in order to achieve the above object, a program according to claim 7 comprises: a latent image forming unit that exposes the surface of a charged and rotating image carrier to form an electrostatic latent image; and fatty acid metal salt particles. A developing unit that develops the electrostatic latent image with a developer containing toner to which an external additive is added to form a toner image on the image holding member; and the image holding after the toner image is transferred. A program for controlling an image forming apparatus comprising: a cleaning unit that cleans an image carrier in contact with a body, wherein a plurality of computers are arranged in a direction intersecting the rotation direction of the surface of the image carrier. The image holding is performed by setting a region other than the region where the integrated value of the image information for each of the plurality of regions is equal to or less than a predetermined threshold in a predetermined range along the rotation direction as the target region. Said predetermined on the body The latent image forming means is controlled to form an electrostatic latent image in a portion other than the portion corresponding to the target region in the non-image forming region after the range, and formation of the electrostatic latent image in the non-image forming region It functions as a control means for controlling the developing means so that the fatty acid metal salt particles separated from the toner are supplied to the portions where no toner is present.

  According to the first, second, and seventh aspects of the invention, the wear level difference of the photosensitive member is reduced.

  According to the third aspect of the present invention, the supply amount of the fatty acid metal salt particles is controlled as compared with the case where the present invention is not applied.

  According to the fourth aspect of the present invention, the wear step of the photosensitive member can be reduced more easily than in the case where the present invention is not applied.

  According to the fifth and sixth aspects of the invention, the wear level difference of the photosensitive member can be reduced more easily than in the case where the present invention is not applied.

1 is a schematic side view illustrating an example of a configuration of an image forming apparatus according to an embodiment. 2 is a block diagram illustrating an example of a configuration of a control system of the image forming apparatus according to the embodiment. FIG. 3 is a block diagram illustrating an example of a configuration of a control system of the image forming unit according to the embodiment. FIG. It is a flowchart which shows the flow of a process of the ZnSt supply data creation process program which concerns on embodiment. It is a schematic diagram for demonstrating the ZnSt supply data creation process which concerns on embodiment. It is explanatory drawing for demonstrating the quantity of the ZnSt particle | grains of a photoreceptor surface. It is explanatory drawing for demonstrating the relationship between the position of the axial direction of a photoconductor, and an integrated image amount. It is explanatory drawing for demonstrating the ZnSt supply image which concerns on embodiment, and the flowchart which shows a ZnSt supply process. It is a schematic diagram showing a test pattern for image formation according to an example.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

<Image forming apparatus>
First, the main configuration of the image forming apparatus will be described.
FIG. 1 is a schematic side view showing an example of the configuration of an image forming apparatus according to an embodiment of the present invention. As shown in FIG. 1, an image forming apparatus 10 according to the present embodiment is provided with, for example, an electrophotographic photosensitive member (hereinafter referred to as “photosensitive member”) 12. The photosensitive member 12 has a cylindrical shape, and is connected to a driving unit 27 such as a motor via a driving force propagation member (not shown) such as a gear, and around the rotation axis indicated by a black dot by the driving unit 27. Driven by rotation. In the example shown in FIG. 1, it is rotationally driven in the direction of arrow A.

  Around the photosensitive member 12, for example, a charging device 15, a latent image forming device 16, a developing device 18, a transfer device 31, a cleaning device 22, and a charge eliminating device 24 are sequentially arranged along the rotation direction of the photosensitive member 12. Has been. The image forming apparatus 10 according to the present embodiment is also provided with a fixing device 26. Details of each part of the image forming apparatus 10 will be described below.

(Photoconductor)
The photoreceptor 12 includes, for example, a conductive substrate, an undercoat layer formed on the conductive substrate, and a photosensitive layer formed on the undercoat layer. This photosensitive layer may have a two-layer structure of a charge generation layer and a charge transport layer. Further, the photosensitive layer may have a configuration in which a protective layer is provided on the outermost surface. The undercoat layer includes a binder resin, metal oxide particles, and an electron accepting compound.

(Charging device)
The charging device 15 charges the surface of the photoconductor 12. The charging device 15 includes, for example, a charging member 14 that is provided in contact or non-contact with the surface of the photoconductor 12 and charges the surface of the photoconductor 12, and a power supply 28 that applies a charging voltage to the charging member 14. Yes. The power source 28 is electrically connected to the charging member 14.

  Examples of the charging member 14 of the charging device 15 include a contact-type charger using a conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, and the like. Examples of the charging member 14 include a non-contact type roller charger and a known charger such as a scorotron charger using a corona discharge or a corotron charger.

The charging device 15 (including the power supply 28) is electrically connected to, for example, a control unit 36 provided in the image forming apparatus 10, and is driven and controlled by the control unit 36 to apply a charging voltage to the charging member 14. To do. The charging member 14 to which the charging voltage is applied from the power supply 28 charges the photoconductor 12 to a charging potential corresponding to the applied charging voltage. Therefore, the photosensitive member 12 is charged to a different charging potential by adjusting the charging voltage applied from the power source 28.
The polarity of the charging potential is not particularly limited, but in the present embodiment, as an example, it is a negative potential (hereinafter, this potential may be referred to as “dark potential”).

(Latent image forming device)
The latent image forming device 16 forms an electrostatic latent image on the surface of the charged photoreceptor 12. Specifically, for example, the latent image forming device 16 is electrically connected to a control unit 36 provided in the image forming device 10, is driven and controlled by the control unit 36, and is charged by the charging member 14. The surface of the photoconductor 12 is irradiated with light L modulated based on image information indicating an image to be formed, and an electrostatic latent image corresponding to the image indicated by the image information is formed on the photoconductor 12. .

Examples of the latent image forming device 16 include optical equipment having a light source that exposes light such as semiconductor laser light, LED light, and liquid crystal shutter light imagewise.
By this exposure, the potential of the exposed portion (exposure potential) on the surface of the photoconductor 12 is set higher than the potential of the portion not exposed (dark potential).

(Developer)
The developing device 18 is provided, for example, on the downstream side in the rotation direction of the photoconductor 12 from the irradiation position of the light L by the latent image forming device 16. In the developing device 18, an accommodating portion for accommodating the developer is provided. In the present embodiment, the container contains a developer containing toner to which fatty acid metal salt particles are externally added. For example, the toner is stored in a charged state in the developing device 18. The charging polarity of the toner is not particularly limited, but in the present embodiment, it is negative as an example. The developer will be described later.

  The developing device 18 includes, for example, a developing member 18A that develops an electrostatic latent image formed on the surface of the photoreceptor 12 with a developer containing toner, and a power source 32 that applies a developing voltage to the developing member 18A. It consists of The developing member 18A is electrically connected to the power source 32, for example.

  The developing member 18A of the developing device 18 is selected according to the type of developer, and examples thereof include a developing roll having a developing sleeve with a built-in magnet.

  The developing device 18 (including the power source 32) is electrically connected to a control unit 36 provided in the image forming apparatus 10, for example, and is driven and controlled by the control unit 36 to apply a developing voltage to the developing member 18A. To do. The developing member 18A to which the developing potential is applied holds, for example, the developer accommodated in the developing device 18 on the surface, and the toner contained in the developer is transferred from the developing device 18 to the surface of the photoconductor 12. Supply.

  For example, the toner supplied onto the photoconductor 12 adheres to the electrostatic latent image on the photoconductor 12 by electrostatic force. Specifically, for example, the toner contained in the developer by the potential difference in the area where the photosensitive member 12 and the developing member 18A face each other, that is, the potential difference between the surface potential of the photosensitive member 12 and the developing potential of the developing member 18A in the region. Is supplied to the area of the photoreceptor 12 where the electrostatic latent image is formed. If the developer contains a carrier, the carrier returns to the developing device 18 while being held by the developing member 18A.

  For example, the electrostatic latent image on the photoconductor 12 is developed with toner supplied from the developing member 18 </ b> A, and a toner image corresponding to the electrostatic latent image is formed on the photoconductor 12.

(Transfer device)
For example, the transfer device 31 is provided on the downstream side in the rotation direction of the photoconductor 12 from the position where the developing member 18A is disposed. The transfer device 31 includes, for example, a transfer member 20 that transfers a toner image formed on the surface of the photoreceptor 12 to a recording medium 30A (for example, recording paper), and a power supply 30 that applies a transfer voltage to the transfer member 20. It is configured to include. The transfer member 20 has, for example, a cylindrical shape, and conveys the recording medium 30 </ b> A with the photoreceptor 12. The transfer member 20 is electrically connected to, for example, a power supply 30.

  As the transfer member 20, for example, a contact type transfer charger using a belt, a roller, a film, a rubber blade or the like, a scorotron transfer charger using a corona discharge, a corotron transfer charger, or the like known per se. Examples include a charger.

  The transfer device 31 (including the power supply 30) is electrically connected to, for example, a control unit 36 provided in the image forming apparatus 10, and is driven and controlled by the control unit 36 to apply a transfer voltage to the transfer member 20. To do. The transfer member 20 to which the transfer voltage is applied has a transfer potential corresponding to the transfer voltage.

  When a transfer voltage having a polarity opposite to that of the toner constituting the toner image formed on the photoconductor 12 is applied from the power source 30 of the transfer member 20 to the transfer member 20, for example, between the photoconductor 12 and the transfer member 20. In the facing area (see transfer area 32A in FIG. 1), an electric field is formed to move each toner constituting the toner image on the photoconductor 12 from the photoconductor 12 to the transfer member 20 side by electrostatic force.

  For example, the recording medium 30 </ b> A is stored in a storage unit (not illustrated), and is transported along the transport path 34 by a plurality of transport members (not illustrated) from the storage unit. It reaches the transfer area 32A, which is an opposing area. In the example shown in FIG. 1, it is conveyed in the direction of arrow B. For example, when a transfer voltage is applied to the transfer member 20, the toner image on the photoconductor 12 is transferred to the recording medium 30 </ b> A that has reached the transfer area 32 </ b> A by the electric field formed in the area. That is, for example, the toner image is transferred onto the recording medium 30A by the movement of the toner from the surface of the photoreceptor 12 to the recording medium 30A.

(Cleaning device)
The cleaning device 22 is provided on the downstream side in the rotation direction of the photoconductor 12 from the transfer region 32A. The cleaning device 22 transfers the toner image to the recording medium 30 </ b> A, and then removes the adhering matter adhering to the photoconductor 12. The cleaning device 22 removes deposits such as residual toner and paper dust on the photoconductor 12. In the present embodiment, the cleaning device 22 has a plate-like member (hereinafter referred to as “cleaning blade”) 22 </ b> A that contacts the photoconductor 12 with a predetermined linear pressure. The cleaning blade 22A is in contact with the photoconductor 12 at a linear pressure of 10 g / cm or more and 150 g / cm or less, for example.

(Staticizer)
The neutralization device 24 is provided, for example, downstream of the cleaning device 22 in the rotation direction of the photosensitive member 12. The neutralization device 24 transfers the toner image and then exposes the surface of the photoconductor 12 to neutralize the charge. Specifically, for example, the static eliminator 24 is electrically connected to a control unit 36 provided in the image forming apparatus 10, and is driven and controlled by the control unit 36 so that the entire surface of the photoconductor 12 (specifically, For example, the entire surface of the image forming area is exposed to remove electricity.

  Examples of the static eliminating device 24 include a device having a light source such as a tungsten lamp that emits white light and a light emitting diode (LED) that emits red light.

(Fixing device)
For example, the fixing device 26 is provided on the downstream side in the transport direction of the transport path 34 of the recording medium 30A from the transfer region 32A. The fixing device 26 fixes the toner image transferred onto the recording medium 30A. Specifically, for example, the fixing device 26 is electrically connected to a control unit 36 provided in the image forming apparatus 10, and is toner that is driven and controlled by the control unit 36 and transferred onto the recording medium 30 </ b> A. The image is fixed on the recording medium 30A by heat or heat and pressure.

  Examples of the fixing device 26 include a known fixing device such as a heat roller fixing device and an oven fixing device.

  Here, the recording medium 30 </ b> A to which the toner image is transferred by being transported along the transport path 34 and passing through the region (transfer region 32 </ b> A) where the photoconductor 12 and the transfer member 20 face each other is omitted, for example. The conveying member further reaches the installation position of the fixing device 26 along the conveying path 34, and the toner image on the recording medium 30A is fixed.

  The recording medium 30A on which the image is formed by fixing the toner image is discharged to the outside of the image forming apparatus 10 by a plurality of conveyance members (not shown). The photosensitive member 12 is charged to the charging potential by the charging device 15 again after the charge removal by the charge removal device 24.

(Image forming operation)
Here, an image forming operation of the image forming apparatus 10 will be described.
First, the surface of the photoreceptor 12 is charged by the charging device 15. The latent image forming device 16 exposes the surface of the charged photoreceptor 12 based on image information. As a result, an electrostatic latent image corresponding to the image information is formed on the photoreceptor 12. In the developing device 18, the electrostatic latent image formed on the surface of the photoreceptor 12 is developed by a developer containing toner. As a result, a toner image is formed on the surface of the photoreceptor 12. In the transfer device 31, the toner image formed on the surface of the photoreceptor 12 is transferred to the recording medium 30A. The toner image transferred to the recording medium 30 </ b> A is fixed by the fixing device 26. On the other hand, the surface of the photoconductor 12 after the toner image is transferred is cleaned by the cleaning device 22 and discharged by the discharging device 24.

<Control system of image forming apparatus>
Next, a control system of the image forming apparatus will be described.
FIG. 2 is a block diagram showing an example of the configuration of the control system of the image forming apparatus shown in FIG. FIG. 3 is a block diagram showing the configuration of the control system of the image forming unit shown in FIG. As shown in FIG. 2, in addition to the control unit 36, the image forming apparatus 10 according to the present embodiment includes an operation display unit 40, an image processing unit 42, an image memory 44, an image forming unit 46, a storage unit 48, and A communication unit 50 is provided.

  The control unit 36 is configured as a computer that controls the entire apparatus and performs various calculations. Specifically, the control unit 36 includes a CPU (Central Processing Unit) 36A, a ROM (Read Only Memory) 36B storing various programs, and a RAM (Random Access Memory) used as a work area when executing the programs. 36C, a non-volatile memory 36D for storing various information, and an input / output interface (I / O) 36E. Each of the CPU 36A, ROM 36B, RAM 36C, nonvolatile memory 36D, and I / O 36E is connected via a bus 36F.

  The operation display unit 40, the image processing unit 42, the image memory 44, the image forming unit 46, the storage unit 48, and the communication unit 50 are connected to the I / O 36E of the control unit 36. The control unit 36 exchanges information with each unit of the operation display unit 40, the image processing unit 42, the image memory 44, the image forming unit 46, the storage unit 48, and the communication unit 50, and controls each unit.

  The operation display unit 40 includes various buttons such as a start button and a numeric keypad, and a touch panel display for displaying various screens such as a warning screen and a setting screen. With the above configuration, the operation display unit 40 receives operations from the user and displays various information to the user.

  The image processing unit 42 performs predetermined image processing on the image information acquired from the external device 52 via the communication unit 50, and generates image information to be output to the image forming unit 46. For example, PDL data described in a page description language is expanded and converted into raster data (RGB data) that has been expanded into RGB colors, and the RGB data is color-converted and reproduced by the image forming apparatus. Generates YMCK data expressed in color. Furthermore, screen processing, gamma correction processing, or the like may be performed.

  The image memory 44 stores various image information acquired by the image forming apparatus 10 such as image information acquired from the external device 52 and image information generated by the image processing unit 42. In the present embodiment, the image memory 44 stores at least image information after image processing by the image processing unit 42, that is, image information to be output to the image forming unit 46. Hereinafter, in order to simplify the description, image information to be output to the image forming unit 46 will be described as “K color (black) single color” raster data.

  The image forming unit 46 constitutes a main part of the image forming apparatus 10. As shown in FIG. 3, the control system of the image forming unit 46 includes a driving unit 27 of the photosensitive member 12, a charging device 15 (including a power source 28), a latent image forming device 16, a developing device 18 (including a power source 32), The image forming apparatus includes a transfer device 31 (including a power supply 30), a charge eliminating device 24, and a fixing device 26. Each of the drive unit 27, the charging device 15, the latent image forming device 16, the developing device 18, the transfer device 31, the charge removal device 24, and the fixing device 26 is connected to the control unit 36. The control unit 36 exchanges information with each of these units and controls each unit.

  The storage unit 48 includes a storage device such as a hard disk. The storage unit 48 stores various data such as log data, various programs, and the like. The communication unit 50 is an interface for communicating with the external device 52 via a wired or wireless communication line. For example, the communication unit 50 acquires image formation information together with an image formation instruction and image information of an electronic document from an external device. The image formation information includes parameters representing attributes such as page, number of copies, and color mode.

  In the present embodiment, a case will be described in which a ZnSt supply data creation processing program (hereinafter simply referred to as a “processing program”) described later is stored in advance in the ROM 36B. The processing program stored in advance is read by the CPU 36A and executed using the RAM 36C as a work area. In the present embodiment, a case will be described in which various setting values such as a threshold value of an accumulated image amount described later are stored in advance in the nonvolatile memory 36D. Note that the processing program and the set value may be stored in another storage device such as the storage unit 48 or may be acquired from the outside via the communication unit 50. Moreover, you may acquire via various storage media, such as CD-ROM.

  Various drives may be connected to the control unit 36. Various drives are devices that read data from a computer-readable portable recording medium such as a flexible disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, and a USB memory, and write data to the recording medium. It is. When various drives are provided, the processing program may be recorded on a portable recording medium, and read and executed by a corresponding drive.

(Developer)
The developer according to the present embodiment is a developer including a toner to which an external additive including fatty acid metal salt particles is externally added. Note that the developer may be a one-component developer including a toner alone or a two-component developer including a toner and a carrier.

  Specifically, the toner includes, for example, toner particles and an external additive including fatty acid metal salt particles.

  Examples of the toner particles include known toner particles having a volume average particle diameter of 3 μm or more and 9 μm or less, including a binder resin and, if necessary, a colorant, a release agent, and other additives.

  The external additive may contain inorganic particles in addition to the fatty acid metal salt particles.

The fatty acid metal salt particle is a salt particle composed of a fatty acid and a metal.
Examples of the fatty acid include fatty acids having 10 to 25 carbon atoms. Examples of the metal include magnesium, calcium, aluminum, barium, and zinc. Zinc is particularly preferable.

  Examples of the fatty acid metal salt particles include aluminum stearate, calcium stearate, potassium stearate, magnesium stearate, barium stearate, lithium stearate, zinc stearate, copper stearate, lead stearate, nickel stearate, stearic acid. Strontium, cobalt stearate, sodium stearate, zinc oleate, manganese oleate, iron oleate, aluminum oleate, copper oleate, magnesium oleate, calcium oleate, zinc palmitate, cobalt palmitate, copper palmitate, Magnesium palmitate, Aluminum palmitate, Calcium palmitate, Zinc laurate, Manganese laurate, Calcium laurate, Iron laurate, Lauri Magnesium acid, aluminum laurate, zinc linoleate, cobalt linoleate, calcium linoleate, zinc ricinoleate, and each particle, such as ricinoleic acid aluminum.

  Among these, as fatty acid metal salt particles, particles of zinc stearate, zinc laurate, and magnesium stearate are preferable, and zinc stearate particles are more preferable.

  The volume average particle diameter of the fatty acid metal salt particles is, for example, preferably from 0.1 μm to 10 μm, preferably from 0.3 μm to 6 μm, and more preferably from 4 μm to 6 μm.

  The external addition amount of the fatty acid metal salt particles is, for example, preferably 0.02 to 5 parts by mass, and preferably 0.05 to 0.5 parts by mass with respect to 100 parts by mass of the toner particles.

On the other hand, as inorganic particles, for example, SiO ₂ , TiO ₂ , Al ₂ O ₃ , CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , MgO, BaO, CaO, K ₂ O, Na ₂ O, ZrO _{2, CaO · SiO 2, K} 2 O · (TiO 2) n, Al 2 O 3 · 2SiO 2, CaCO 3, MgCO 3, BaSO 4, MgSO 4 , etc. particles. Among these, SiO ₂ particles (silica particles) are preferable.

  The volume average particle diameter of the inorganic particles is, for example, preferably from 80 nm to 180 nm, and preferably from 100 nm to 180 nm.

The surface of the inorganic particles is preferably subjected to a hydrophobic treatment. The hydrophobic treatment is performed, for example, by immersing inorganic particles in a hydrophobic treatment agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents and the like. These may be used individually by 1 type and may use 2 or more types together.
The amount of the hydrophobizing agent is usually, for example, 1 part by mass or more and 10 parts by mass with respect to 100 parts by mass of the inorganic particles.

  For example, the external addition amount of the inorganic particles is preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.01% by mass or more and 2.0% by mass or less with respect to the toner particles.

  In addition, the volume average particle diameter (D50v) of each external additive is measured using an LS Coulter (a particle size measuring device manufactured by Coulter, Inc.). In the particle size distribution of the measured particles, a cumulative distribution is drawn from the smaller diameter side with respect to the divided particle size range (channel), and the particle size that becomes 50% cumulative is the volume average particle size (D50v). It is defined as

<About the generation of wear steps on the photoreceptor>
It is known that fatty acid metal salt particles such as zinc stearate particles are externally added as external additives for toner in order to reduce wear of the photoreceptor 12 due to friction with the cleaning blade 22A. This is presumably because the fatty acid metal salt particles are uniformly applied onto the surface of the photoreceptor 12 to protect the photoreceptor layer and thus reduce the wear. Hereinafter, zinc stearate particles will be exemplified and described as the fatty acid metal salt particles. In addition, zinc stearate is sometimes referred to as “ZnSt”.

  Here, even if ZnSt is externally added to the toner as ZnSt particles, there is a problem in that the distribution of ZnSt particles on the surface of the photoreceptor 12 is biased in the image forming process of the image forming apparatus 10. That is, the ZnSt particles are mainly abundant in the non-image forming area (the area where no image is formed on the surface of the photoconductor 12), while the image forming area (the area where the image is formed on the surface of the photoconductor 12). ), The amount of ZnSt particles becomes insufficient. This is because the ZnSt particles are positively charged, and the ZnSt particles selectively fly to the non-image area when developing the toner on the photoreceptor 12. .

  Accordingly, when images having the same or similar image configuration are continuously formed over a long period of time in the image forming apparatus 10, the amount of wear differs between the image forming area and the non-image forming area, and the photoconductor There are wear steps on the 12 surfaces. If the amount of wear is different, for example, the exposure potential when the latent image is formed by the latent image forming device 16 may vary, and defects such as density unevenness may occur.

  On the other hand, as a supply form of ZnSt particles, there is known a form in which a dedicated supply device is provided in the image forming apparatus, and the coating is uniformly applied to the surface of the photoreceptor. However, in such a form, an appropriate amount cannot be supplied to an appropriate position on the photoreceptor, and therefore it is difficult to effectively reduce the wear step. In addition, for example, filming which is the adhesion of foreign matter may occur due to excessive supply of ZnSt particles.

  Furthermore, the excessively supplied ZnSt particles may slip through the cleaning blade 22A and contaminate the contact-type charger (charging roll). In a contaminated charging roll, defective discharge occurs, so that potential unevenness occurs on the surface of the photoreceptor 12, and as a result, image deterioration may occur.

<ZnSt supply data creation process>
Before describing the ZnSt supply data creation processing according to the present embodiment, the concept of the present embodiment will be described.

  The above-described wear level difference on the surface of the photoreceptor 12 becomes a state in which ZnSt particles are abundant in the non-image forming area and ZnSt particles are insufficient in the image forming area as image formation in the image forming apparatus 10 proceeds. It is due to that. Therefore, in the present embodiment, when the photoconductor 12 is rotated by a predetermined number of rotations during image formation, there is a non-image forming region that continues for a predetermined length in the rotation direction of the photoconductor 12. By detecting whether or not ZnSt particles are present on the photoconductor 12 by detecting whether or not they are present, the position thereof is specified and predicted, and the position, that is, the image forming region adjacent to the continuous non-image forming region is ZnSt. Supplying particles.

  Specifically, based on image information input to the image forming apparatus 10, each block formed by dividing an image formed on the photoconductor 12 into a plurality of pieces in the axial direction (longitudinal direction) of the photoconductor 12 corresponds to the block. By accumulating the gradation values of the image information to obtain the integrated image amount, the position of the photoconductor 12 in the axial direction is specified, and the occurrence of a wear step on the photoconductor 12 is predicted. Then, by forming a ZnSt supply image at the predicted position and supplying ZnSt particles, the wear on the surface of the photoconductor 12 is prevented from progressing at the position so that the wear step on the surface of the photoconductor 12 is reduced. I try to reduce it.

  The integrated image amount is a value obtained by integrating the density value for each pixel of the image represented by the image information for each block. In the case of K single color (monochrome image), the density value for each pixel is represented by binary values of “0 (white)” and “1 (black)”. A pixel “1 (black)” is an ON pixel on which toner is placed. Therefore, the integrated value of the density values for each pixel of the image represented by the image information is the same as the integrated pixel number of the image represented by the image information (the integrated value of the on pixels on which the toner is placed). In the present embodiment, a case where the accumulated image amount is “the accumulated pixel number” will be described.

  Next, the operation of the image forming apparatus 10 according to the present embodiment when executing the ZnSt supply data creation process will be described with reference to FIG. FIG. 4 is a flowchart showing a processing flow of a ZnSt supply data creation processing program read from, for example, the ROM 36B and executed by the CPU 36A at this time. Here, a case where a non-image forming area is detected will be described. The ZnSt supply data creation processing program is started when, for example, a print instruction or the like related to unit processing (so-called job) is received from an external device via the communication unit 50. Information acquired during processing is stored in the RAM 36C, which is a work area, and used as necessary.

As shown in FIG. 4, first, in step S400, image information for one unit process (one job) (here, image information image-processed by the image processing unit 42, hereinafter referred to as “processing target image information”). Is acquired from the image memory 44.
Next, in step S402, the history of integration information stored in the nonvolatile memory 36D for the processing target image information that has been set as the processing target image information up to this point is read. The integrated information according to the present embodiment is information including the integrated image amount GM and the rotational speed N of the photoconductor 12.

  As described above, the integration of the image information is an image formed on the photoconductor 12 when image formation is performed using the processing target image information (hereinafter referred to as “photosensitive body formation image”). This is done for each block divided in the axial direction. Therefore, when the number of divisions is M, there are M values of the accumulated image amount GM, GM1, GM2,. When the image forming apparatus 10 is used for the first time, or when the accumulated image amount GM has been reset up to this point, the value of each GM is zero. The rotational speed N is the cumulative rotational speed of the photoconductor 12 up to this point, and the value of N is 0 when the image forming apparatus 10 is used for the first time or when it has been reset by this point. .

Next, in step S404, integrated information of the processing target image information is obtained. That is, based on the processing target image information, the integrated image amount GM for each block is calculated, and the total number of rotations of the photoconductor 12 required to execute the processing target image information is calculated.
Next, in step S406, the newly calculated integrated image amount is updated in addition to the integrated image amount GM up to this point read in step S402. Further, the newly calculated number of revolutions is added to the number of revolutions N up to this point to update the number of revolutions N. The updated accumulated image amount GM and rotation speed N are stored in the nonvolatile memory 36D as accumulated information. If this is the first time, the data is stored in the nonvolatile memory 36D without being updated.

  Next, in step S408, it is determined whether or not there is a block that satisfies the continuous formation condition 1 indicating that the non-image forming regions are continuous. There may be a plurality of blocks that satisfy the continuous formation condition 1, and in this case, the processes of the subsequent steps S410 to S414 are executed for each of the plurality of blocks. Details of the continuous formation condition 1 will be described later.

If a negative determination is made in step S408, the ZnSt supply data creation processing program is terminated, whereas if an affirmative determination is made, the process proceeds to the next step S410.
In step 410, a block that is determined to satisfy continuous formation condition 1 in step S408 in a non-image forming area (for example, between continuous recording media 30A) in which image formation is not performed immediately after continuous formation condition 1 is satisfied. Image information for forming a ZnSt supply image is generated at a position corresponding to.

Next, in step S412, the image information of the ZnSt supply image generated in step S410 is combined with the processing target image information. Here, synthesizing the image information of the ZnSt supply image with the processing target image information means that the image information of the ZnSt supply image is part of the processing target image information.
Next, in step S414, the integration information is reset (GM = 0, N = 0), and then the ZnSt supply data creation processing program is terminated. The integration information GM is reset in units of blocks, that is, units of GM1, GM2,.

  With the above processing, it is determined whether or not it is necessary to supply ZnSt particles, and if necessary, the position where the ZnSt supply image is to be formed is synthesized as processing target image information. In the image forming process related to the processing target image information that is subsequently executed, an appropriate amount of ZnSt particles is supplied to an appropriate position by performing image formation based on the processing target image information obtained by combining the ZnSt supply data.

  Next, the content of the ZnSt supply data creation process will be specifically described with reference to FIGS.

As shown in FIG. 5A, the image PG for one page is composed of an image portion Pg on which toner is placed and a non-image portion Png on which toner is not placed. FIG. 5B is a development view of an image formed on the surface of the photosensitive member 12 (photosensitive member formation image) for six rotations in the image forming process. As shown in FIG. 5B, on the surface of the photoreceptor 12, there are an image forming region Rg where a latent image and a toner image are formed, and a non-image forming region Rng where a latent image and a toner image are not formed. . In FIG. 5B, numbers Rg and Rng are numbered from the first rotation such as Rg1 and Rng1, respectively. In FIG. 5B, image information corresponding to an image formed by one rotation of the k-th photoconductor 12 is represented by Gk (1 ≦ k ≦ L, where L is a unit processing image forming process). The total number of rotations of the photoconductor 12 required for the above).
ZB1 shown in FIG. 5B shows a ZnSt supply image, which will be described later, formed in the non-image forming region Rng3.

  As described above, in the present embodiment, the axial direction of the photoconductor 12 is divided into M blocks, and an integrated image amount GM is obtained for each block. FIG. 5 (b) shows a form when M = 5, and each block is represented by B1 to B5. The integrated image amount GM for each block is denoted by GMi (1 ≦ i ≦ M) by adding a block number. Further, in the following, when each block is not distinguished, it may be simply expressed as “integrated image amount GM”. Note that the number of axial divisions of the photoconductor 12 for calculating the accumulated image amount is not limited to five, and may be an appropriate number in consideration of the accuracy of the supply position of ZnSt particles, the calculation time, and the like.

When the same or similar images are continuously formed as shown in FIG. 5B, the distribution of ZnSt particles on the photoreceptor 12 is biased as described above.
FIG. 6 is a diagram conceptually showing the distribution deviation of the ZnSt particles, where the horizontal axis represents the position in the axial direction of the photoreceptor 12, that is, blocks B1 to B5, and the vertical axis represents the amount of ZnSt particles (arbitrary scale a .U.).

  In the image formation of FIG. 5B, since the blocks B1 and B5 are non-image forming regions and the blocks B2, B3, and B4 are image forming regions, the amount of ZnSt particles is large in the blocks B1 and B5. There are few states in blocks B2, B3, and B4. If this state continues as it is, the wear of the photoconductor 12 proceeds in the blocks B2, B3, and B4, and a wear step is likely to occur between the blocks B1 and B5.

Therefore, in the present embodiment, when the photoconductor 12 rotates by a predetermined number of rotations, the same or similar accumulated image amount continuously satisfies a predetermined threshold condition, the ZnSt particles Judge that supply is necessary. The condition of the threshold value of the accumulated image amount at this time is referred to as “continuous formation condition”.
In the present embodiment, the continuous forming condition is defined by the rotational speed Nmin of the photosensitive member and the threshold value GMmin of the accumulated image amount for detecting the continuous non-image forming area. The unit of GMmin is the number of pixels.

That is, the continuous formation conditions are as follows.
(Condition 1) Continuous formation condition of non-image forming region: GM when the photoreceptor 12 rotates by Nmin satisfies GM <GMmin. And, in the case of Condition 1, a target region for supplying ZnSt particles is detected. An area other than the marked area is assumed.
Here, as specific values of Nmin and GMmin, for example, Nmin = 80 (rotation) and GMmin = 2 are set.

FIG. 7A shows a conceptual diagram of the accumulated image amounts GM1 to GM5 when the non-image forming area is detected and the photosensitive member 12 is rotated Nmin times. In FIG. 7A, the horizontal axis indicates the position of the photosensitive member 12 in the axial direction, that is, the blocks B1 to B5, and the vertical axis indicates the accumulated image amount GM.
In the present embodiment, the rotational speed N and the accumulated image amount GM are calculated and accumulated in the execution of image formation of each unit process. Accordingly, in the unit processing ZnSt supply data creation processing program, the current rotation speed N and the accumulated image amount GM are obtained and added to the rotation speed N and the accumulated image amount GM in the image forming process up to this point to rotate. The number N and the accumulated image amount GM are updated.

  In FIG. 7A, it can be seen that the non-image forming area B1 and the non-image forming area B5 satisfy the continuous forming condition 1. Therefore, according to the above rules, regions other than the blocks B1 and B5, that is, the blocks B2 to B4 (image forming regions) are set as target regions for supplying ZnSt particles. In the present embodiment, a ZnSt supply image is formed at a position where supply of ZnSt particles is necessary, and ZnSt particles are supplied. In the present embodiment, a ZnSt supply image is formed in the non-image forming region Rng immediately after the continuous formation condition 1 is detected. However, the position where the ZnSt-supplied image is formed is not limited to this. For example, it may be formed in the non-image forming region Rng before the position where the continuous formation condition 1 is detected, or the head of unit processing May be formed in the non-image forming region Rng.

  FIG. 8A is a diagram schematically showing the ZnSt supply image ZB1. In the present embodiment, in the exposure process by the latent image forming device 16, a ZnSt supply image ZB1 is formed in which the target region to which the ZnSt particles are to be supplied is the non-exposed portion NE and the other region is the exposed portion E. In ZB1 shown in FIG. 8A, the blocks B1 and B5 are the exposure part E, and the blocks B2 to B4 are the non-exposure part NE. In the present embodiment, as an example, the potential of the non-exposed portion NE is set lower than the potential of the exposed portion E. The “non-exposed portion” does not exist as a region, but will be described in the following manner as a region that may be an exposed portion.

FIG. 8B shows a flowchart of the supply process for supplying ZnSt using the ZnSt supply image ZB1 formed as described above. This supply process is executed by the CPU 36A during unit process image formation.
First, in step S800, the arrival of the ZnSt supply image ZB1 is detected. When it is detected that the arrival has occurred, the ZnSt supply image ZB1 is developed at a normal development potential in step S802, and toner is supplied to the ZnSt supply image ZB1. The In the next step S804, toner is supplied until the ZnSt supply image ZB1 is completed. When it is detected that the supply is completed, the supply process is ended.

When the ZnSt supply image ZB1 is formed as described above, the toner to which ZnSt particles are externally added is supplied to the exposure unit E in the developing process by the developing device 18. Then, the positively charged ZnSt particles easily move to the non-exposed portion NE having a relatively lower potential than the exposed portion E. Therefore, a part of the ZnSt particles supplied together with the toner to the blocks B1 and B5 that are the exposed portion E Moves to the blocks B2 to B4 which are the non-exposed portions NE. That is, the developing device 18 is controlled so that the ZnSt particles separated from the toner are supplied to the portion where the potential of the non-image forming region Rng is lowered.
In blocks B2 to B4, it has been predicted that the surface of the photoconductor 12 is further worn and wear steps are generated in relation to the blocks B1 and B5. However, ZnSt particles are supplied to the blocks B2 to B4 by the above processing. Therefore, the wear level difference on the surface of the photoreceptor 12 is reduced.

  Further, in the present embodiment, an appropriate amount of ZnSt particles is supplied to the necessary region, so that excessive supply on the surface of the photoreceptor 12 is prevented and contamination of the charging roll is prevented. As a result, the occurrence of uneven potential on the surface of the photoreceptor 12 is suppressed.

Here, the supply amount of the ZnSt particles may be adjusted by the area of the ZnSt supply image ZB1 and the density of the image to be formed. Assuming that an area gradation rate (hereinafter referred to as “Cin”) is used as a scale indicating the density of an image, ZB1 is set to, for example, an image of Cin 100% of 700 mm. The width of ZB1 is, for example, the width of the block in the axial direction. In this case, since the width of ZB1 depends on the number of blocks, it is desirable to increase the number of blocks and reduce the width. In this embodiment, the case where the number of blocks is 5 is described by way of example in order to avoid complications, but the number of blocks is preferably at least 5 or more.
Note that the area gradation rate (Cin) is the ratio of the area ratio of on dots (black) and off dots (white) to make it look gray in a pseudo manner with respect to the area corresponding to all pixels in a certain region. The ratio of the area occupied by on dots (black).

<When detecting continuous image forming areas>
In the above-described embodiment, an example using a method of detecting a continuous non-image forming area has been described, but the present invention is not limited to this, and a continuous image forming area may be detected. The continuous formation conditions in this case are as follows.
(Condition 2) Continuous formation condition of the image forming area: GM when the photosensitive member 12 rotates by Nmax satisfies GM> GMmax. In the case of Condition 2, the target area for supplying ZnSt is detected. This is an area.
Here, specific values of Nmax and GMmax are, for example, Nmax = 160 (rotation) and GMmax = 100.

In the flowchart of the ZnSt supply data creation processing program in this case, it may be determined in step S408 in FIG. 4 whether there is a block that satisfies the continuous formation condition in the continuous formation condition 2 of the image formation region.
Note that Nmin and Nmax are not necessarily different, and may be the same value.

FIG. 7B shows a conceptual diagram of the accumulated image amounts GM1 to GM5 when the photosensitive member 12 is rotated Nmax times when the condition 2 is detected.
When the condition 2 is detected, since the blocks B2 and B4 are detected in FIG. 7B, the blocks B2 and B4 are set as the target regions for supplying ZnSt particles according to the above rules. Therefore, the ZnSt supply image forms the ZnSt supply image with the blocks B2 and B4 as the non-exposed portion NE and the other blocks as the exposed portion E. Thus, even if the condition 2 is detected, the same result as that obtained when the condition 1 is detected can be obtained.

  In the above embodiment, the position where the ZnSt supply image is formed in advance is obtained as ZnSt supply data based on the image information of the unit process, and this ZnSt supply data is combined with the image information of the unit process to execute image formation. However, while the embodiment of supplying ZnSt particles has been described as an example, the present invention is not limited to this. For example, the rotational speed N and the integrated image amount GM of the photoconductor 12 are calculated while performing unit-process image formation, and when the continuous formation condition is detected, formation data of a ZnSt supply image is generated and ZnSt particles are supplied. You may do it.

  In the above embodiment, the rotation speed is used as a condition for determining the non-image forming area or the image forming area based on the accumulated image amount. However, the present invention is not limited to this, and for example, an image is formed. The cumulative number of recording papers, the cumulative peripheral length in the rotation direction of the photoconductor 12, or the like may be used.

  In the above-described embodiment, the toner is supplied to the exposed portion E on the photosensitive member 12 by way of example. However, the present invention is not limited to this, and the non-exposed portion NE is not limited to this. Positively charged ZnSt particles may be supplied. In this case, for example, the development potential is raised to near the exposure potential, and positively charged ZnSt particles are supplied by the potential difference between the development potential and the potential (dark potential) of the non-exposed portion NE. In this case, the supply amount of ZnSt particles is controlled by the development potential. In this supply form, ZnSt particles are directly supplied to the region to be supplied.

In this case, FIG. 8C shows a flowchart of the supply process for supplying ZnSt particles from the ZnSt supply image. This supply process is executed by the CPU 36A during unit process image formation.
First, in step S806, the arrival of the ZnSt supply image is awaited, and when it is detected that the arrival has occurred, the development potential is set to a predetermined potential in the next step S808. In the present embodiment, the predetermined potential is a potential increased to a value close to the exposure potential. Next, when it is detected in step S810 that the ZnSt supply image has been completed, the development potential is returned to the original potential (normal development potential) in the next step S812, and this supply processing is terminated.

  Furthermore, the configurations of the image forming apparatus and the program described in the above embodiments are examples, and the configurations may be changed without departing from the gist of the present invention. For example, in the illustrated flowchart, some steps may be omitted, and other steps may be added. Moreover, you may replace the order of each step as needed.

  Hereinafter, the image forming apparatus of the present embodiment will be specifically described with reference to examples, but the present invention is not limited to these examples. Further, unless otherwise specified, “part” represents “part by mass” and “%” represents “mass%”.

[Production of developer]
(Preparation of developer 1)
-Production of toner particles-
-Preparation of polyester resin particle dispersion-
・ Ethylene glycol [Wako Pure Chemical Industries, Ltd.] 37 parts ・ Neopentyl glycol [Wako Pure Chemical Industries, Ltd.] 65 parts ・ 1,9 Nonanediol [Wako Pure Chemical Industries, Ltd.] 32 parts ・96 parts of terephthalic acid [manufactured by Wako Pure Chemical Industries, Ltd.] The above monomer was charged into a flask, and the temperature was raised to 200 ° C. over 1 hour. After confirming that the reaction system was stirred, dibutyltin oxide was added. 1.2 parts were added. Further, while distilling off the generated water, the temperature was increased from the same temperature to 240 ° C. over 6 hours, and the dehydration condensation reaction was continued at 240 ° C. for another 4 hours. The acid value was 9.4 mgKOH / g, and the weight average molecular weight. A polyester resin A having a glass transition temperature of 13,000 and 62 ° C. was obtained.

Subsequently, the polyester resin A was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 parts per minute. A 0.37% diluted aqueous ammonia solution obtained by diluting reagent ammonia water with ion-exchanged water is put into a separately prepared aqueous medium tank, and the polyester is heated at 120 ° C. with a heat exchanger at a rate of 0.1 liter per minute. The resin melt was transferred to the Cavitron along with the resin melt. A resin particle having a volume average particle size of 160 nm, a solid content of 30%, a glass transition temperature of 62 ° C., and a weight average molecular weight Mw of 13,000 is operated under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ^2. A polyester resin particle dispersion in which is dispersed is obtained.

-Preparation of colorant particle dispersion-
-Cyan pigment [C.I. I. Pigment Blue 15: 3, manufactured by Dainichi Seika Kogyo Co., Ltd.] 10 parts, anionic surfactant [Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] 2 parts, ion-exchanged water 80 parts Dispersion was carried out for 1 hour using an impact disperser ultimateizer [HJP30006, manufactured by Sugino Machine Co., Ltd.] to obtain a colorant particle dispersion having a volume average particle size of 180 nm and a solid content of 20%.

-Preparation of release agent particle dispersion-
Carnauba wax (RC-160, melting temperature 84 ° C., manufactured by Toa Kasei Co., Ltd.) 50 parts Anionic surfactant [Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] 2 parts ・ Ion-exchanged water 200 parts After heating to ℃ and mixing and dispersing with IKA's Ultra Turrax T50, dispersion with a pressure discharge type homogenizer gives a release agent particle dispersion with a volume average particle size of 200 nm and a solid content of 20%. It was.

-Production of toner particles-
・ Polyester resin particle dispersion 200 parts ・ Colorant particle dispersion 25 parts ・ Releasing agent particle dispersion: 30 parts ・ Polyaluminum chloride 0.4 part ・ Ion-exchanged water 100 parts The above ingredients are put into a stainless steel flask. After mixing and dispersing using IKA's ultra turrax, the flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 30 minutes, 70 parts of the same polyester resin particle dispersion as above was added thereto.

Then, after adjusting the pH in the system to 8.0 using an aqueous sodium hydroxide solution having a concentration of 0.5 mol / L, the stainless steel flask is sealed, and the stirring shaft seal is magnetically sealed while stirring is continued. Heat to 90 ° C. and hold for 3 hours. After completion of the reaction, the temperature was lowered at a rate of 2 ° C./min, filtered, washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed with 3 L of ion exchange water at 30 ° C., and stirred and washed at 300 rpm for 15 minutes. This washing operation was further repeated 6 times, and when the pH of the filtrate became 7.54 and the electric conductivity was 6.5 μS / cm, No. was obtained by Nutsche suction filtration. Solid-liquid separation was performed using 5A filter paper. Next, vacuum drying was continued for 12 hours to obtain toner particles.
When the volume average particle diameter D50v of the toner particles 1 is measured with a Coulter counter, it is 5.8 μm, and SF1 is 130.

-Production of Toner 1-
To 100 parts of toner particles, 0.5 parts of zinc stearate particles (manufactured by NOF Corporation: volume average particle size (D50v) 5.5 μm) and silica particles (volume average particle size (D50v) 120 nm) are used as external additives. 2 parts were added and mixed with a Henschel mixer at 2000 rpm for 3 minutes to obtain each toner 1.

-Production of Developer 1-
Each obtained toner and carrier were put in a V blender at a ratio of toner: carrier = 5: 95 (mass ratio) and stirred for 20 minutes to obtain each developer.

In addition, the carrier produced as follows was used.
Ferrite particles (volume average particle diameter: 50 μm) 100 parts toluene 14 parts styrene-methyl methacrylate copolymer 2 parts (component ratio: 90/10, Mw = 80000)
Carbon black (R330: manufactured by Cabot Corporation) 0.2 part First, the above components excluding ferrite particles are stirred with a stirrer for 10 minutes to prepare a dispersed coating solution, and then the coating solution and ferrite particles are combined. After putting in a vacuum degassing type kneader and stirring at 60 ° C. for 30 minutes, the carrier was obtained by further depressurizing while heating and degassing and drying.

(Preparation of developer 2)
In accordance with Table 1, Developer 2 was prepared in the same manner as Developer 1, except that the amount of external addition of zinc stearate particles as an external additive (ZnSt particle external addition amount) was changed.

[Examples 1-5, Comparative Examples 1-3]
“700 Digital Color Press” manufactured by Fuji Xerox Co., Ltd. was used as an image forming apparatus. A developer according to Table 1 was used as the developer. This image forming apparatus has the same configuration as the image forming apparatus shown in FIG. 1, and is further modified so that the control unit 36 executes a ZnSt supply data creation processing program.

The above-described image forming apparatus sequentially forms the test pattern shown in FIG. 9 on a 50000-cycle recording paper while supplying ZnSt particles with the arrival of predetermined conditions under an environmental condition of 10 ° C. and 15% RH. The amount of wear in the image forming area (indicated as “image portion” in Table 1), the amount of wear in the non-image forming area (indicated as “non-image portion” in Table 1), the difference in wear amount, and the writing density of 100% An image density difference (hereinafter referred to as “density difference”. In Table 1, expressed as “ΔSAD”) was evaluated. The ZnSt particles were supplied by forming a ZnSt supply image on the photoreceptor. The evaluation results are shown in Table 1.
However, in Comparative Examples 1 and 2, the supply of ZnSt particles was not performed.
In Comparative Example 3, the ZnSt particles were not supplied, and solid ZnSt was supplied to the entire surface of the photoreceptor at a coating amount of 0.05 mg · cm ² by brush application at an early stage before image formation.

(Test pattern)
In this embodiment, two types of test patterns for image formation shown in FIG. 9 were used. FIG. 9A shows a test pattern TP1 for forming a non-image forming area and an adjacent image forming area, and no image is formed in the non-image forming area. FIG. 9B similarly shows a test pattern TP2 for forming a non-image forming area and an adjacent image forming area. In the portion corresponding to the non-image forming area of TP1, the non-image forming area and the image forming area are shown. This is a test pattern in which regions are alternately formed.

(Non-image forming area threshold)
In the image forming process, the ZnSt particle supply timing is a threshold value of the non-image forming region indicating that the non-image forming region has continued for a predetermined length (in Table 1, “non-image portion threshold value”). The point in time is exceeded.
The non-image forming area threshold for TP1 is the length of the non-image forming area on the photoconductor 12 (the integrated value of the peripheral length of the photoconductor 12). TP1 is used in Examples 1 to 4 and Comparative Example 3, and the threshold value is 10500 mm.
The image forming area threshold for TP2 is used in the fifth embodiment, and the value is 2100000 mm. The threshold for TP2 is multiplied by 100 of Cin 100% because the threshold for TP1 is doubled (because non-image forming areas and image forming areas come alternately) in order to make the detection conditions similar to TP1.

(Supply of ZnSt particles)
A ZnSt supply image shown in FIG. 8A was formed by a ZnSt supply data creation processing program. The supply amount of ZnSt particles was defined by Cin and the length of the supplied image. The supply method is a method of supplying toner to the image forming area.

-Evaluation of wear amount of photoconductor-
The amount of wear in the image forming area and non-image forming area of the photoreceptor after running for 50000 cycles was measured. Measurement was performed at 3 points in the axial direction of the photosensitive member and 20 points in the rotational direction, and the average value was defined as the wear amount in the image forming region and the wear amount in the non-image forming region. The difference between the two was taken as the difference in wear. The film thickness of the photoconductor was measured using an eddy current film thickness measuring apparatus (Fischer Instruments).
―Evaluation of concentration difference―
After running for 50000 cycles, a halftone image of Cin 30% was formed, and the density of portions corresponding to the image forming area and the non-image forming area of TP1 was measured at five points, and the density difference was calculated and evaluated. As the concentration measuring apparatus, X-rite 938 (manufactured by X-rite) was used. The evaluation criteria for the concentration difference are as follows.
○: Concentration difference <0.005 ... no problem △: 0.005 ≤ concentration difference <0.01 ... There is a slight density difference but there is no problem in actual use ×: Concentration difference ≥ 0.01・ There is a problem in actual use

  From the results of Table 1, it can be seen that in this example, the difference in the amount of wear on the surface of the photoreceptor is suppressed even when there are continuous non-image forming areas and image forming areas. In addition, when the supply amount of ZnSt particles is about 100% Cin and about 700 mm, it can be seen that the difference in wear amount and the difference in concentration are good (Examples 1 to 4). Further, it can be seen that even when a region where a non-image forming region and an image forming region coexist is detected, a good result is obtained with a difference in wear amount and a difference in density (Example 5).

  On the other hand, when there is no supply of ZnSt particles, both the wear amount difference and the concentration difference show large values, indicating that this does not depend on the external addition amount of ZnSt particles (Comparative Example 1 and Comparative Example 2). It can also be seen that even when the ZnSt particles are uniformly applied with a brush, both the wear amount difference and the concentration difference show large values (Comparative Example 3). This is presumably because the wear amount difference cannot be eliminated only by applying uniformly.

DESCRIPTION OF SYMBOLS 10 Image forming device 12 Photoconductor 14 Charging member 15 Charging device 16 Latent image forming device 18 Developing device 18A Developing member 20 Transfer member 22 Cleaning device 22A Cleaning blade 24 Neutralizing device 26 Fixing device 27 Driving unit 28 Power supply 30 Power source 30A Recording medium 31 Transfer device 32 Power supply 32A Transfer area 34 Transport path 36 Control unit 36A CPU
36B ROM
36C RAM
36D non-volatile memory 36E I / O
36F bus 40 operation display unit 42 image processing unit 44 image memory 46 image forming unit 48 storage unit 50 communication unit 52 external devices B1 to B5 blocks G1 to G6 image information PG page image Pg image unit Png non-image unit Rg image forming region Rng Non-image forming area TP1, TP2 Test pattern

Claims (7)

The electrostatic image is formed by the latent image forming means for exposing the surface of the charged and rotating image carrier to form an electrostatic latent image, and the developer including the toner externally added with the fatty acid metal salt particles. Developing means for developing a latent image to form a toner image on the image carrier;
Cleaning means for cleaning the image carrier in contact with the image carrier after the toner image is transferred;
The surface of the image carrier is divided into a plurality of regions in a direction crossing the rotation direction, and an integrated value of image information for each of the plurality of regions is determined in a predetermined range along the rotation direction. An area other than the area below the threshold is set as a target area, and an electrostatic latent image is formed on a portion other than the portion corresponding to the target area of the non-image forming area after the predetermined range on the image carrier. And controlling the developing means so that the fatty acid metal salt particles separated from the toner are supplied to a portion of the non-image forming area where no electrostatic latent image is formed. Means,
An image forming apparatus.   The control means sets, as the target area, an area in which the integrated value is equal to or greater than a threshold value greater than the predetermined threshold, and sets the non-image forming area after the predetermined range on the image carrier. The image forming apparatus according to claim 1, wherein the latent image forming unit is controlled to form an electrostatic latent image in a portion other than the portion corresponding to the target area.   The control means develops the electrostatic latent image on a portion of the image carrier other than the portion corresponding to the target area of the non-image forming area to form a toner image, and separates the toner from the target area The image forming apparatus according to claim 1, wherein the developing unit is controlled so that the fatty acid metal salt particles are supplied.   The control means synthesizes the image information and image information indicating an electrostatic latent image formed in a portion other than the portion corresponding to the target region of the non-image forming region to obtain composite image information, and the composite image information The developing unit controls the latent image forming unit so that an electrostatic latent image is formed based on the toner image, and supplies the fatty acid metal salt particles separated from the toner to the target region of the non-image forming region. The image forming apparatus according to any one of claims 1 to 3, wherein the image forming apparatus is controlled.   5. The image forming apparatus according to claim 1, wherein the predetermined range is defined by the number of rotations of the image holding member accompanying image formation based on image information.   The image forming apparatus according to claim 1, wherein the predetermined range is defined by the number of recording media on which an image is formed based on image information. The electrostatic image is formed by the latent image forming means for exposing the surface of the charged and rotating image carrier to form an electrostatic latent image, and the developer including the toner externally added with the fatty acid metal salt particles. Developing means for developing a latent image to form a toner image on the image carrier;
Cleaning means for cleaning the image carrier in contact with the image carrier after the toner image is transferred;
A program for controlling an image forming apparatus comprising:
Computer
The surface of the image carrier is divided into a plurality of regions in a direction crossing the rotation direction, and an integrated value of image information for each of the plurality of regions is determined in a predetermined range along the rotation direction. An area other than the area below the threshold is set as a target area, and an electrostatic latent image is formed on a portion other than the portion corresponding to the target area of the non-image forming area after the predetermined range on the image carrier. And controlling the developing means so that the fatty acid metal salt particles separated from the toner are supplied to a portion of the non-image forming area where no electrostatic latent image is formed. Means,
Program to function as.