Image forming apparatus

Abstract

To provide an image forming apparatus that uses a developer including metal soap, and prevent a harmful effect on an image occurring due to the metal soap while preventing an increase in torque of a photoreceptor.SOLUTION: An image forming apparatus has: an image carrier; a developing member that supplies a toner containing metal soap having a polarity opposite to that of the toner to form a toner image; a supply member that supplies the toner to the developing member; and a control unit that executes an image forming operation for forming the toner image on a recording material, and a metal soap supply operation for supplying the metal soap from the developing member to a surface of the image carrier in a non-image forming period. The metal soap supply operation includes a first mode and a second mode, and the potential difference formed between the supply member and the developing member and causing an electrostatic force directed from the supply member toward the developing member to act on the metal soap, is smaller during the execution of the metal soap supply operation in the second mode than during the execution of the metal soap supply operation in the first mode.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] As an electrophotographic photoreceptor (hereinafter, also simply referred to as "photoreceptor") used in an electrophotographic image forming apparatus, organic photoreceptors have become widespread due to the advantages of low cost and high productivity. This is composed of a photosensitive layer (organic photosensitive layer) using an organic material as a photoconductive substance (charge generating substance or charge transporting substance) provided on a support. In the photoreceptor, electrical external forces and mechanical external forces are directly applied in each of the processes of charging, exposure, development, transfer, and cleaning, so durability against these external forces is required. Specifically, durability against the occurrence of surface scratches and abrasion due to these external forces, that is, scratch resistance and abrasion resistance are required.

[0003] However, when the surface hardness of the photoreceptor is increased to obtain abrasion resistance, the surface becomes difficult to be shaved, so that discharge products such as ozone and NOx generated by discharge on the photoreceptor surface due to charging are difficult to be removed from the photoreceptor surface. As a result, the friction coefficient of the photoreceptor surface becomes high and the torque becomes high. When the torque becomes high, the load on the drive motor increases, the power consumption increases, or the motor becomes difficult to start, so it is desirable to suppress the increase in torque. As a method for suppressing the increase in the torque of the photoreceptor, Patent Document 1 describes a method of containing a metal soap in a developer and supplying the metal soap from a developer carrier to the photoreceptor surface. Specifically, zinc stearate, which is a metal soap, is supplied to the surface of the photoreceptor by a developer carrier, and the surface of the photoreceptor is coated with zinc stearate to suppress the adhesion of discharge products.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] However, when the technology described in Patent Document 1 is used in a long-life cartridge, for example, metal soap supplied to the photoreceptor surface by the end of its lifespan may transfer to the charging roller via the photoreceptor and coat the surface of the charging roller. When this coating occurs on the charging roller, it does not charge properly, resulting in image defects.

[0006] The present invention aims to suppress image defects caused by metal soap while suppressing an increase in the torque of the photoreceptor in an image forming apparatus using a developer containing metal soap. [Means for solving the problem]

[0007] The present invention provides a rotatable image carrier, A developing member in a developing section facing the image carrier supplies toner to the surface of the image carrier to form a toner image, A supply member that supplies the toner to the developing member, A control unit that performs an image forming operation for forming the toner image on the recording material, and a metal soap supply operation for supplying a metal soap with the opposite polarity to the toner contained in the toner from the developing member to the surface of the image carrier when not forming an image, It has, The operating modes of the metal soap supply operation include a first mode and a second mode, and the supply The potential difference that causes an electrostatic force to act on the metal soap in the direction from the supply member to the developing member, formed between the member and the developing member, is smaller when the metal soap supply operation of the second mode is performed than when the metal soap supply operation of the first mode is performed.

[0008] Furthermore, the present invention includes a rotatable image carrier, A developing member in a developing section facing the image carrier supplies toner to the surface of the image carrier to form a toner image, A supply member that supplies the toner to the developing member, A control unit that performs an image forming operation for forming the toner image on a recording material, and a metal soap supply operation for supplying the toner from the developing member to the surface of the image carrier when not forming an image, thereby applying a metal soap with the opposite polarity to the toner contained in the toner to the surface of the image carrier, It has, The operation modes of the metal soap supply operation include a first mode and a second mode, characterized in that the amount of metal soap supplied from the developing member to the surface of the image carrier is less when the metal soap supply operation in the second mode is performed than when the metal soap supply operation in the first mode is performed.

[0009] Furthermore, the present invention includes a rotatable image carrier, The developing unit, facing the image carrier, includes a developing member that supplies toner to the surface of the image carrier to form a toner image. A control unit that performs an initial operation to transition the image carrier from a new state to a printable state, and an image forming operation to form the toner image on the recording material, It has, The first peripheral speed ratio, which is the ratio of the surface movement speed of the developing member to the surface movement speed of the image carrier during at least a portion of the execution of the initial operation, is characterized in that it is greater than the second peripheral speed ratio, which is the ratio of the surface movement speed of the developing member to the surface movement speed of the image carrier during the execution of the image forming operation. [Effects of the Invention]

[0010] According to the present invention, in an image forming apparatus using a developer containing a metal soap, it is possible to suppress the increase in torque of the photoreceptor while suppressing image defects caused by the metal soap. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view of the image forming apparatus in Example 1. [Figure 2]It is a cross-sectional view of the process cartridge in Example 1. [Figure 3] It is a control block diagram of the image forming apparatus in Example 1. [Figure 4] It is a schematic diagram of the toner in Example 1. [Figure 5] It is a flowchart in Example 1. [Figure 6] It is a diagram for explaining ΔVr and the transfer amount of metal soap in Example 1. [Figure 7] It is a diagram for explaining the DD peripheral speed ratio and the transfer amount of metal soap in Example 2. [Figure 8] It is a diagram for explaining the DD peripheral speed ratio and the fog amount on the photoreceptor in Example 2. [Figure 9] It is a diagram for explaining the pre-exposure amount and the influence on the torque of the photoreceptor in Example 3.

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following description is illustrative and does not limit the present invention to its content. Also, in the following respective figures, descriptions of components that are not necessary for the description of the embodiments are omitted as appropriate. <_{}

[0013] (Example 1) 1. Image Forming Apparatus The overall configuration of the electrophotographic image forming apparatus in Example 1 will be described. Here, an image forming apparatus is a device that forms an image on a recording material (recording medium) using an electrophotographic image forming method. Examples of image forming apparatuses include copiers, printers (laser beam printers, LED printers, etc.), facsimile machines, word processors, and their combined devices (multifunction printers). Figure 1 is a schematic cross-sectional view of the image forming apparatus 100 of Example 1. The image forming apparatus 100 of Example 1 is a full-color laser printer employing an in-line method and an intermediate transfer method. The image forming apparatus 100 can form a full-color image on a recording material S (for example, recording paper, plastic sheet, cloth, etc.) according to image information. Image information is input to the image forming apparatus 100 from an image reading device (not shown) connected to the image forming apparatus 100, or from a host device (not shown) such as a personal computer that is communicatively connected to the image forming apparatus 100.

[0014] The image forming apparatus 100 has a plurality of image forming sections, the first, second, third, and fourth image forming sections SY, SM, SC, and SK, each for forming images of yellow (Y), magenta (M), cyan (C), and black (K), respectively.

[0015] In Example 1, the image forming apparatus 100 has four drum-shaped electrophotographic photoreceptors (hereinafter referred to as photoreceptors) 1 arranged in a direction intersecting the vertical direction as multiple image carriers. The photoreceptors 1 and the image forming units (SY, SM, SC, and SK) are integrated to form a process cartridge 7.

[0016] The photoreceptor 1, which serves as an image carrier for holding an electrostatic latent image, is rotated in the direction of arrow A in Figure 2 by a driving means (not shown). The charging roller 2, which is a charging member, is a single-layer roller consisting of a conductive core and a conductive rubber layer, with an outer diameter of φ7.5 mm and a volume resistivity of 10. 3 ~10 6The voltage is Ω·cm. Then, by applying a charging voltage of -1000V to the charging roller 2 using the charging voltage application unit 71, which is a high-voltage power supply described later, the surface of the photoreceptor 1 is uniformly charged to -500V. A DC voltage consisting of Vd + Vth is applied to the charging roller 2, and the photoreceptor 1 is uniformly charged with Vd by discharge. Here, Vd is the dark area potential, which is -500V. Vth is the discharge initiation voltage, and when the applied charging voltage is small, the surface potential on the photoreceptor 1 does not increase by discharge, but from the discharge initiation voltage Vth onwards, the surface potential begins to increase by discharge. In other words, the discharge initiation voltage Vth in Example 1 is -500V.

[0017] After the surface of the photoreceptor 1 is charged by the charging roller 2, the surface of the photoreceptor 1 is irradiated with laser light from the exposure unit 30. The exposure unit 30 is an exposure means that irradiates a laser based on image information to form an electrostatic latent image on the surface of the photoreceptor 1. The surface potential of the photoreceptor 1 irradiated with laser light changes to -100V as the bright area potential Vl, and an electrostatic latent image is formed.

[0018] Figure 2 is a cross-sectional view of the process cartridge 7 of Embodiment 1, viewed in the longitudinal direction (direction of the rotation axis) of the photoreceptor 1. The process cartridge 7 consists of a developing unit 3 and a photoreceptor unit 13. The developing unit 3 is equipped with a developing roller 4, which is a developing member, and a toner supply roller (hereinafter referred to as "supply roller") 5, which is a toner supply member. Driven by a drive motor (not shown), the developing roller 4 rotates in the direction of arrow D in Figure 2, and the supply roller 5 rotates in the direction of arrow R in Figure 2. A voltage of -300V is applied to the developing roller 4 as a developing voltage from the developing high voltage 72, which is a developing voltage application unit, and the developing agent (toner) is supplied by the developing roller 4 to the electrostatic latent image formed on the surface of the photoreceptor 1, i.e., the Vl portion mentioned above, and developed.

[0019] The developer image (toner image) developed on the surface of the photoreceptor 1 is transferred to the intermediate transfer belt 31 shown in Figure 1. The intermediate transfer belt 31 is an intermediate transfer body that can come into contact with and separate from each of the photoreceptors 1 of the image forming sections SY, SM, SC, and SK. It is formed as an endless belt that faces the photoreceptor 1 and transfers the toner image on the photoreceptor 1 to the recording material S. The intermediate transfer belt 31 comes into contact with each of the photoreceptors 1 of the image forming sections SY, SM, SC, and SK and moves (rotates) in a circulating manner in the direction of arrow B (counterclockwise) in Figure 1.

[0020] On the inner circumferential surface of the intermediate transfer belt 31, primary transfer rollers 32, which are transfer members, are arranged so as to face each of the photoreceptors 1 of the image forming sections SY, SM, SC, and SK via the intermediate transfer belt 31. A voltage with the opposite polarity to the normal charge polarity of the toner is applied to the primary transfer rollers 32 from the primary transfer voltage power supply (primary transfer high voltage) 73. As a result, the toner image on the photoreceptor 1 is transferred (primary transfer) onto the intermediate transfer belt 31. In Example 1, the polarity of the toner is set to negative polarity as the normal polarity. Therefore, primary transfer can be performed by applying a positive polarity voltage as the primary transfer voltage.

[0021] A secondary transfer roller 33, acting as a secondary transfer means, is positioned on the outer circumferential surface of the intermediate transfer belt 31. A voltage opposite to the polarity of the toner is applied to the secondary transfer roller 33 from a secondary transfer voltage power supply (secondary transfer high voltage) 74, which acts as a secondary transfer voltage application unit. This transfers the toner image on the intermediate transfer belt 31 to the recording material S (secondary transfer). During full-color image formation, the above process is performed sequentially in the image formation units SY, SM, SC, and SK, and the toner images of each color are sequentially superimposed on the intermediate transfer belt 31 for primary transfer. Subsequently, the recording material S is transported to the secondary transfer unit in synchronization with the movement of the intermediate transfer belt 31. Then, through the action of the secondary transfer roller 33, which is in contact with the intermediate transfer belt 31 via the recording material S, the four-color toner images on the intermediate transfer belt 31 are collectively transferred to the recording material S for secondary transfer.

[0022] The recording material S onto which the toner image has been transferred is transported to the fixing device 34. In the fixing device 34, heat and pressure are applied to the recording material S, fixing the toner image to the recording material S, and the recording material S is discharged outside the image forming apparatus 100.

[0023] On the other hand, the surface potential of the photoreceptor 1 after toner has been transferred to the intermediate transfer belt 31 is non-uniform due to the primary transfer voltage. Therefore, the pre-exposure unit 27 exposes the entire surface of the photoreceptor 1 (entire surface light irradiation) to equalize the surface potential of the photoreceptor 1, which has become non-uniform due to the previous image formation. Pre-exposure removes residual charge from the surface of the photoreceptor 1. The pre-exposure unit 27 exposes the surface of the photoreceptor 1 in the direction of rotation of the photoreceptor 1, downstream from the contact point with the intermediate transfer belt 31 and upstream from the charged portion where the charging roller 2 and the photoreceptor 1 come into contact. An LED, halogen lamp, etc. can be used as the light source for the pre-exposure unit 27. The light source used is not particularly limited, but from the viewpoint of low driving voltage and ease of miniaturization of the device, it is preferable to use an LED, so in Example 1, an LED was used as the pre-exposure light source.

[0024] Toner that remains on the surface of the photoreceptor 1 without being transferred to the intermediate transfer belt 31 by the primary transfer roller 32 is scraped off from the surface of the photoreceptor 1 by the cleaning blade 8, which is in contact with the photoreceptor 1. It is then collected in the waste toner storage chamber 9 located below the cleaning blade 8. Toner that remains on the intermediate transfer belt 31 without being transferred to the recording material S by the secondary transfer roller 33 is transported to the intermediate transfer body cleaning device 35, which acts as a cleaning device, and removed.

[0025] 2. Control Modes of Image Forming Apparatus Figure 3 is a block diagram showing the logical relationships between the components of the image forming apparatus 100 in Embodiment 1. The control unit 202, which controls the operation of the image forming apparatus 100, receives and outputs signals indicating various information via electrical connections. The control unit 202 processes signals input from various process equipment and sensors, and processes signals output to command the operation of various process equipment. The controller 200 inputs and outputs various signals to and from the host device, and inputs and outputs various signals to and from the control unit 202 via the interface 201, thereby comprehensively controlling the image forming operation of the image forming apparatus 100 according to a predetermined control program and reference table. The control unit 202 has a CPU 155, which is a central element that performs various calculations, and memory 15 such as RAM and ROM, which are memory elements. The RAM stores sensor detection results, counter count results, calculation results, etc., and the ROM stores the control program, data tables obtained in advance through experiments, etc. Various control targets, sensors, counters, etc. in the image forming apparatus 100 are connected to the control unit 202. The control unit 202 controls the input and output of various signals and the timing of the drives of each part to control a predetermined image formation sequence. For example, it controls the following high-voltage power supply and devices to form a toner image on the surface of the photoreceptor 1: the charging high voltage 71 as a charging power supply, the developing high voltage 72 as a developing power supply, the supply high voltage 75 that supplies the toner supply voltage as the power supply for the supply roller 5, the developing blade high voltage 76 as the power supply for the toner regulating member 6, and the exposure unit 30. Furthermore, it controls the primary transfer high voltage 73 as a primary transfer power supply and the secondary transfer high voltage 74 as a secondary transfer power supply to form a toner image on the recording material S. In addition, it controls the contact / separation mechanism 50 that controls the contact / separation between the developing roller 4 and the photoreceptor 1, the torque detection mechanism 51 of the drive motor for the photoreceptor 1, and the cartridge memory communication mechanism 52 that records the usage history of the cartridge. In Embodiment 1, the control unit 202 controls the above high voltages, etc., in order to perform the metal soap supply operation (coating operation), which will be described in detail later.

[0026] 3. Outline configuration of the process cartridge The overall configuration of the process cartridge 7 installed in the image forming apparatus 100 of Example 1 will be explained with reference to Figure 2. The process cartridge 7 is detachable from the image forming apparatus 100 via mounting means such as mounting guides and positioning members (not shown) provided on the image forming apparatus 100. In Example 1, all process cartridges 7 for each color have the same shape, and each process cartridge 7 contains toner 10 of yellow (Y), magenta (M), cyan (C), and black (K), respectively.

[0027] In Example 1, the configuration and operation of the process cartridge 7 for each color are substantially the same, except for the type (color) of toner 10 contained within.

[0028] The process cartridge 7 includes a developing unit 3 equipped with a developing roller 4, etc., and a photoreceptor unit 13 equipped with a photoreceptor 1.

[0029] In Example 1, the developing unit 3 and the photoreceptor unit 13 are integrated into a process cartridge 7, but the system is not limited to this configuration. They may also be configured to be detachable from the image forming apparatus 100 as a developing cartridge and a photoreceptor cartridge, respectively.

[0030] The developing unit 3 is divided into a developing chamber 3a and a toner storage section 3b. The toner storage section 3b is provided with a toner transport member 22 for transporting toner 10 to the developing chamber 3a, and the toner 10 is transported to the developing chamber 3a by rotating in the direction of arrow G in the figure.

[0031] The developing chamber 3a is provided with a developing roller 4, which acts as a toner carrier and rotates in the direction of arrow D in the diagram while in contact with the photoreceptor 1. In Embodiment 1, the developing roller 4 and the photoreceptor 1 rotate in opposite developing sections so that their surfaces move in the same direction.

[0032] Furthermore, inside the developing chamber 3a, there is a supply roller 5 that supplies toner 10 transported from the toner storage unit 3b to the developing roller 4, and a toner regulating member 6 that regulates the amount of toner 10 coated on the developing roller 4 supplied by the supply roller 5 and applies a charge.

[0033] Independent voltages are applied to the developing roller 4, the supply roller 5, and the toner regulating member 6 from a high-voltage power supply. The toner 10 supplied to the developing roller 4 by the supply roller 5 is triboelectrically charged by friction between the developing roller 4 and the toner regulating member 6, thereby imparting an electric charge and simultaneously regulating the layer thickness. The regulated toner 10 on the developing roller 4 is transported to the part opposite the photoreceptor 1 by the rotation of the developing roller 4, developing the electrostatic latent image on the photoreceptor 1 as a toner image and making it visible.

[0034] During image formation, a predetermined DC voltage (developing voltage: Vdc) applied to the developing roller 4 was set to -300V. Additionally, by applying a voltage (supply voltage: Vrs = -350V) to the supply roller 5, the potential difference (ΔVr) between the supply roller 5 and the developing roller 4 was adjusted, thereby controlling the amount of toner 10 supplied to the developing roller 4. In Example 1, ΔVr = Vdc - Vrs was set to +50V, creating a potential setting that facilitates the movement of negatively charged toner from the supply roller 5 to the developing roller 4.

[0035] When developing and visualizing the electrostatic latent image on the photoreceptor 1 as a toner image, the developing roller 4 is rotated in contact with the circumferential surface of the photoreceptor 1. This is to facilitate the supply of the metal soap added to the toner, as described later, onto the photoreceptor 1. Note that the configuration is not limited to the developing roller 4 and the photoreceptor 1 being in contact, as long as a configuration that can supply the metal soap is available.

[0036] In the following explanation, with respect to potential and applied voltage, a large absolute value on the negative side (for example, -1000V compared to -500V) will be referred to as a high potential, and a small absolute value on the negative side (for example, -300V compared to -500V) will be referred to as a low potential. This is because we are considering the negatively charged toner 10 in Example 1 as the reference.

[0037] Furthermore, the voltage in Example 1 is expressed as a potential difference from the ground potential (0V). Therefore, the developing voltage = -300V is interpreted as having a potential difference of -300V with respect to the ground potential due to the developing voltage applied to the core metal of the developing roller 4. This also applies to other voltages such as the charging voltage.

[0038] The photoreceptor unit 13 is rotatably mounted to the photoreceptor unit 13 via a bearing (not shown). The photoreceptor 1 is rotated in the direction of arrow A in Figure 2 by receiving the driving force of a drive motor (not shown). The photoreceptor unit 13 also has a charging roller 2 and a cleaning blade 8, which is a plate-shaped elastic body, positioned to contact the circumferential surface of the photoreceptor 1. One end of the cleaning blade 8 is fixed to a plate-shaped metal sheet, and the other free end abuts against the photoreceptor 1, forming a cleaning nip, which is the contact portion with the photoreceptor 1. The cleaning blade 8 rubs the surface of the photoreceptor 1, scraping off toner 10 and fine particles remaining from the transfer process and collecting them in the waste toner storage chamber 9. This prevents toner 10 from adhering to the charging roller 2 and prevents the photoreceptor 1 from carrying the toner 10 around, which would prevent proper image formation.

[0039] 4. Composition of the photoreceptor The photoreceptor 1 consists of a cylindrical, conductive metal support, a conductive layer as an undercoat for the support, a photosensitive layer (charge generation layer, charge transport layer) formed on the undercoat, and a protective layer formed on the photosensitive layer. The photoreceptor 1 is constructed by mounting a photosensitive material such as OPC (organic photoconductive material), amorphous selenium, or amorphous silicon on a drum base on a cylinder, which serves as a support with an outer diameter of φ24 mm and is made of aluminum, nickel, or the like. In Example 1, the photoreceptor 1 has an abrasion-resistant protective layer on its outermost surface to improve abrasion resistance. By providing a protective layer, durability can be improved.

[0040] The protective layer preferably contains conductive particles and / or charge transport material and a resin. Examples of conductive particles include metal oxide particles such as titanium dioxide, zinc oxide, tin oxide, and indium oxide. Examples of charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these, triarylamine compounds and benzidine compounds are preferred.

[0041] Examples of resins include polyester resin, acrylic resin, phenoxy resin, polycarbonate resin, polystyrene resin, phenolic resin, melamine resin, and epoxy resin. Among these, polycarbonate resin, polyester resin, and acrylic resin are preferred.

[0042] Furthermore, the protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of reactions in this case include thermal polymerization, photopolymerization, and radiation polymerization. Examples of polymerizable functional groups in monomers having a polymerizable functional group include acrylic groups and methacrylic groups. A material having charge transport ability may be used as the monomer having a polymerizable functional group.

[0043] The protective layer may contain additives such as antioxidants, UV absorbers, plasticizers, leveling agents, lubrication agents, and wear resistance enhancers. Specifically, examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles. The average film thickness of the protective layer is preferably 0.5 μm to 10 μm, and more preferably 1 μm to 7 μm.

[0044] The protective layer can be formed by preparing a protective coating solution containing the above-mentioned materials and solvents, forming this coating film, and then drying and / or curing it. Examples of solvents used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, sulfoxide-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. In Example 1, the average film thickness of the protective layer was 3 μm.

[0045] 5. Toner Configuration A schematic diagram of the toner 10 used in Example 1 is shown in Figure 4. In Example 1, an inorganic particle toner 45 is used, in which inorganic silicon 45b is added to the mother particles 45a to ensure fluidity and improve chargeability. The toner used in Example 1 is a non-magnetic, one-component particle polymerization toner with negative charge polarity, and the average particle size is 7 μm.

[0046] Furthermore, in order to reduce the coefficient of friction on the surface of the photoreceptor 1, a metal soap 45c is added in addition to the inorganic silicon 45b. Originally, discharge products are highly adhesive and increase the coefficient of friction on the surface of the photoreceptor 1, but by supplying the metal soap 45c to the surface of the photoreceptor 1, the adhesion of discharge products to the surface of the photoreceptor 1 can be suppressed, and the increase in the coefficient of friction can be suppressed.

[0047] Metal soap 45c is a general term for long-chain fatty acids and metal salts other than sodium and potassium. Specifically, examples include metal salts of fatty acids such as stearic acid, myristic acid, lauric acid, ricinoleic acid, and octic acid, and metal species such as lithium, magnesium, calcium, barium, and zinc. In Example 1, zinc stearate is added as metal soap 45c. However, the type of metal soap 45c is not limited to this, and can also include lead stearate, etc. Cadmium stearate, barium stearate, calcium stearate, aluminum stearate, zinc stearate, magnesium stearate, zinc lauryl stearate, zinc myristate, etc., can also be used as appropriate, and at least one of these should be selected.

[0048] The amount of metal soap 45c added externally should preferably be 0.6 wt% or less. While a higher amount of external addition is effective in suppressing the adhesion of discharge products to the photoreceptor 1, excessive addition reduces the fluidity of the toner, resulting in lower image density in the latter half of the image. This is a phenomenon called reduced tracking ability, where tracking ability decreases as you approach the trailing edge of the recording material when outputting a solid black image. On the other hand, the amount of metal soap 45c added externally should preferably be 0.05 wt% or more. If the amount is too low, the effect of metal soap 45c will not be easily realized.

[0049] The average particle size of the metal soap 45c is preferably between 0.15 μm and 2.0 μm. If the average particle size of the metal soap 45c is smaller than 0.15 μm, it becomes difficult to coat the surface of the photoreceptor 1. This is particularly noticeable when there are grooves on the surface of the photoreceptor 1, as described later. On the other hand, if the particle size is larger than 2.0 μm, it cannot pass through the toner regulating member 6 in the developing unit 3 and is left behind in the developing chamber 3a, making it difficult to supply to the surface of the photoreceptor 1. Hereinafter, the toner mother particles 45a and the external additives 45b and 45c together will be referred to as toner.

[0050] This document describes the method for measuring the average particle size of metal soap 45c. 0.5 g of metal soap 45c was mixed with 10 mL of ethanol and ultrasonically dispersed for 5 minutes using an ultrasonic disperser manufactured by Nippon Seiki Co., Ltd. Next, ethanol was circulated as the measurement solvent. Then, the resulting dispersion of metal soap 45c was added to a Microtrac laser diffraction / scattering particle size distribution analyzer (SPA type) manufactured by Nikkiso Co., Ltd. until the DV (diffractive light intensity), a value related to the integrated scattered light intensity of the particles, reached 0.6 to 0.8. The particle size distribution in this state was then measured, and the median diameter, obtained as the cumulative median diameter (50% diameter), was defined as the average particle size.

[0051] The metal soap 45c with the above average particle size may be produced, for example, by a double decomposition method in which an aqueous solution of a fatty acid salt is reacted with an aqueous solution or dispersion of an inorganic metal salt.

[0052] In Example 1, zinc stearate with an average particle size of 0.60 μm was used. The zinc stearate, as the metal soap 45c, is attached to the toner particles by being charged with the opposite polarity to the toner particles, and is supplied onto the photoreceptor 1 when not forming an image.

[0053] Next, a method for producing toner particles will be described. Known methods can be used to produce toner particles, including the kneading and grinding method and the wet manufacturing method. From the viewpoint of uniform particle size and shape control, the wet manufacturing method is preferred. Furthermore, as a wet manufacturing method, methods such as suspension polymerization, dissolution and suspension, emulsion polymerization and agglutination, and emulsion agglutination can be used.

[0054] In Example 1, a suspension polymerization method is employed. In the suspension polymerization method, first, polymerizable monomers for generating a binder resin and, if necessary, other additives such as colorants are uniformly dissolved or dispersed using a disperser such as a ball mill or ultrasonic disperser to prepare a polymerizable monomer composition. This step is called the preparation step of the polymerizable monomer composition. At this time, polyfunctional monomers, chain transfer agents, waxes or charge control agents as release agents, plasticizers, etc. can be added as appropriate. The following vinyl polymerizable monomers are suitable examples of polymerizable monomers in the suspension polymerization method.

[0055] Styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p Styrene derivatives such as -methoxystyrene and p-phenylstyrene; acrylic polymerizable monomers such as methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, and 2-benzoyloxyethyl acrylate; methyl methacrylate, ethyl methacrylate, and n-propyl methacrylate Methacrylic polymerizable monomers such as methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, diethyl phosphate ethyl methacrylate, and dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, and vinyl formate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropyl ketone.

[0056] Next, the polymerizable monomer composition is added to a pre-prepared aqueous medium, and droplets of the polymerizable monomer composition are formed to the desired toner particle size using a stirrer or disperser with high shear force. This process is called the granulation process. It is preferable that the aqueous medium in the granulation process contains a dispersion stabilizer in order to control the particle size of the toner particles, sharpen the particle size distribution, and suppress the coalescence of toner particles during the manufacturing process. Dispersion stabilizers are generally broadly classified into polymers that exhibit repulsive force due to steric hindrance and poorly water-soluble inorganic compounds that stabilize dispersion through electrostatic repulsion. Fine particles of poorly water-soluble inorganic compounds are suitable for use because they dissolve in acids and alkalis, and can be easily removed by washing with an acid or alkali after polymerization.

[0057] For dispersion stabilizers of poorly water-soluble inorganic compounds, those containing magnesium, calcium, barium, zinc, aluminum, or phosphorus are preferably used. More preferably, those containing magnesium, calcium, aluminum, or phosphorus are desired. Specifically, the following are examples.

[0058] Magnesium phosphate, tricalcium phosphate, aluminum phosphate, zinc phosphate, magnesium carbonate, calcium carbonate, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, hydroxyapatide.

[0059] Organic compounds, such as polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salts of carboxymethylcellulose, and starch, may be used in combination with the above-mentioned dispersion stabilizers. It is preferable to use these dispersion stabilizers in an amount of 0.01 parts by mass to 2.00 parts by mass per 100 parts by mass of polymerizable monomer.

[0060] Furthermore, in order to further refine these dispersion stabilizers, a surfactant may be added in an amount of 0.001 parts by mass or more and 0.1 parts by mass or less per 100 parts by mass of polymerizable monomer. Specifically, commercially available nonionic, anionic, and cationic surfactants can be used. For example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium lauryl sulfate, potassium stearate, and calcium oleate are preferably used.

[0061] After the granulation process, or while the granulation process is being carried out, the polymerizable monomers contained in the polymerizable monomer composition are polymerized at a temperature preferably between 50°C and 90°C to obtain a toner particle dispersion. This process is called the polymerization process. During the polymerization process, it is preferable to stir the mixture to ensure a uniform temperature distribution within the container. When a polymerization initiator is added, it can be added at any timing and for any required time. Furthermore, the temperature may be raised in the latter half of the polymerization reaction to obtain a desired molecular weight distribution. In addition, to remove unreacted polymerizable monomers, by-products, etc., from the system, some of the aqueous medium may be removed by distillation in the latter half of the reaction or after the reaction is completed. The distillation operation can be carried out at atmospheric pressure or under reduced pressure.

[0062] Oil-soluble initiators are generally used as polymerization initiators in suspension polymerization. Examples include the following:

[0063] Azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobis(cyclohexane-1-carbonitride), and 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile; peroxide initiators such as acetylcyclohexylsulfonyl peroxide, diisopropyl peroxycarbonate, decanonyl peroxide, lauroyl peroxide, stearoyl peroxide, propionyl peroxide, acetyl peroxide, tert-butylperoxy-2-ethylhexanoate, benzoyl peroxide, tert-butylperoxyisobutyrate, cyclohexanone peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, tert-butylhydroperoxide, di-tert-butyl peroxide, tert-butylperoxypivalate, and cumenehydroperoxide.

[0064] Polymerization initiators may be used in combination with water-soluble initiators as needed, including the following:

[0065] Ammonium persulfate, potassium persulfate, 2,2'-azobis(N,N'-dimelenisobutyroamidine) hydrochloride, 2,2'-azobis(2-aminodinopropane) hydrochloride, azobis(isobutylamidine) hydrochloride, sodium 2,2'-azobisisobutyronitrile sulfonate, ferrous sulfate, or hydrogen peroxide.

[0066] These polymerization initiators can be used individually or in combination, and chain transfer agents, polymerization inhibitors, etc., can be further added to control the degree of polymerization of the polymerizable monomers. The toner of the present invention may contain an organosilicon polymer, and the organosilicon polymer may have one to three carbon atoms directly bonded to the silicon atoms. The organosilicon polymer may also have a substructure represented as R-SiO3 / 2, where R is a hydrocarbon group having one to six carbon atoms, or R may be a hydrocarbon group having one to three carbon atoms.

[0067] The amount of inorganic silica transferred during water washing was controlled using a Henschel mixer (manufactured by Nippon Coke Industries Co., Ltd.) by changing the external additive conditions: the amount of external additive, the rotation speed of the nozzle tip (peripheral speed), and the rotation time of the nozzle (duration). Table 1 below shows the external additive conditions for toner a. Details regarding the peripheral speed and duration of the external additive conditions are as described in Japanese Patent Publication No. 2016-38591. In addition, 0.20 wt% zinc stearate was added externally to the toner used in Example 1. [Table 1]

[0068] 6. Effects of discharge products on the photoreceptor When performing an image forming operation using the image forming apparatus 100, discharge is generated by the charging roller 2, which may produce discharge products such as ozone and NOx that adhere to the surface of the photoreceptor 1. Although the discharge products are scraped off by the cleaning blade 8 that contacts the photoreceptor 1, if the amount of discharged products exceeds the amount that is scraped off, repeated image forming operations will gradually accumulate the discharge products on the surface of the photoreceptor 1. In the contact charging method, the amount of discharge is less and the amount of discharge products generated is less compared to the corona charging method using a corona charger. However, because there is a tiny gap between the photoreceptor 1 and the charging roller 2, even if only a small amount of discharge products are generated, they tend to adhere to the surface of the photoreceptor 1 due to physical friction between the photoreceptor 1 and the charging roller 2. When discharge products adhere to the surface of the photoreceptor 1, the coefficient of friction between the surface of the photoreceptor 1 and the cleaning blade 8 increases. As a result, the driving torque of the photoreceptor 1 increases, the load on the drive motor increases, the power consumption increases, and the motor becomes difficult to start.

[0069] Therefore, in order to reduce the influence of discharge products, in Example 1, metal soap 45c is supplied to the surface of the photoreceptor 1, and a film of metal soap 45c is formed on the surface of the photoreceptor 1, thereby suppressing the adhesion of discharge products.

[0070] 7. Metal soap application process In Example 1, in addition to the normal image forming operation, a metal soap supply operation (hereinafter also referred to as the metal soap coating operation) is performed, in which metal soap is supplied from the developing roller to the surface of the photoreceptor. The timing for performing the metal soap coating operation is determined to be when the number of prints since the last metal soap coating operation has reached a predetermined number, or when it is determined that the torque during driving is high, and is performed during non-image forming operations when no image forming operation is performed. For example, the metal soap coating operation is performed while the photoreceptor 1 is rotating before the image forming operation, or while the photoreceptor 1 is rotating after the image forming operation. Alternatively, the metal soap coating operation may be performed at a timing specified by the user.

[0071] Furthermore, regarding the metal soap application operation, it was decided that the process cartridge 7 would be executed by selecting from two operating modes, Mode 1 and Mode 2, depending on its usage.

[0072] The first mode is executed when the process cartridge 7 is in its initial state of use, i.e., when the total number of printed pages is below a threshold. In the initial stages of use of the process cartridge 7, the friction coefficient of the surface of the photoreceptor 1 is high, and it is desirable to quickly and actively supply metal soap 45c to the surface of the photoreceptor 1 to reduce the friction coefficient. On the other hand, since the blocking layer made of the external additive has not yet been sufficiently formed between the photoreceptor 1 and the cleaning blade 8, and the cleaning performance is unstable, it is desirable not to supply toner 10.

[0073] Therefore, in the first mode, metal soap 45c is actively supplied, and in order to reduce the coefficient of friction on the surface of the photoreceptor 1, the potential difference ΔVr (=Vdc-Vrs) of the supply roller 5 with respect to the developing roller 4 is set to the opposite polarity to that of the metal soap 45c. That is, the applied voltages of the supply roller 5 and the developing roller 4 are controlled so that a potential difference ΔVr is formed between the supply roller 5 and the developing roller 4, which acts as an electrostatic force on the metal soap 45c in the direction from the supply roller 5 to the developing roller 4. By setting ΔVr to the opposite polarity to that of the charged metal soap 45c, metal soap is applied to the developing roller 4 side. By moving the aluminium soap 45c and suppressing the movement of the metal soap 45c towards the supply roller 5, a large amount of metal soap 45c can be supplied onto the surface of the photoreceptor 1.

[0074] In Example 1, Vdc = -300V, Vrs = -100V, and ΔVr = -200V are set in the first mode. Since the metal soap 45c is positively charged, the metal soap 45c actively moves towards the developing roller 4.

[0075] Furthermore, by applying a charging voltage to control the photoreceptor 1 to a dark area potential Vd, and by setting the development voltage to the same as during the image formation operation, so-called solid white printing is performed, and only the metal soap 45c is developed on the surface of the photoreceptor 1.

[0076] The second mode is executed when the process cartridge 7 is in the middle or later stages of use, that is, when the total number of printed pages exceeds a threshold. In the middle stages of use of the process cartridge 7, a sufficient blocking layer is formed between the photoreceptor 1 and the cleaning blade 8, and it is desirable to periodically supply toner 10 to maintain the blocking layer. On the other hand, it is desirable to reduce the amount of metal soap 45c supplied in order to suppress the phenomenon of metal soap 45c transferring to the charging roller 2 via the photoreceptor 1 and covering the surface of the charging roller 2, which prevents proper charging (charging roller coating).

[0077] Therefore, in the second mode, in order to suppress the coating of the charging roller, metal soap 45c is not actively supplied, and toner 10, which forms a blocking layer component between the photoreceptor 1 and the cleaning blade 8, is supplied. To this end, the applied voltages of the supply roller 5 and the developing roller 4 are controlled so that the potential difference ΔVr, which acts an electrostatic force on the metal soap 45c formed between the supply roller 5 and the developing roller 4 in the direction from the supply roller 5 to the developing roller 4, is smaller than in the first mode. In Example 1, the applied voltages of the supply roller 5 and the developing roller 4 are controlled so that the polarity of the potential difference ΔVr is reversed in the second mode compared to the first mode. In particular, the applied voltages of the supply roller 5 and the developing roller 4 are controlled so that the potential difference ΔVr is the same as during image formation. Specifically, the drive is started under the high-voltage and driving conditions used during image formation, the photoreceptor 1 is irradiated with a laser, and a certain amount of toner 10 is supplied. Vdc=-300V, Vrs=-350V, and ΔVr=+50V are set during the second mode. Since the metal soap 45c is positively charged, it is attracted to the supply roller 5, and the movement of the metal soap 45c toward the developing roller 4 is limited to the amount that adheres to the toner 10. Therefore, the amount of metal soap 45c supplied can be reduced.

[0078] As described above, in Example 1, the control unit 202 performs an image forming operation to form a toner image on the recording material S and a coating operation to apply metal soap 45c to the surface of the photoreceptor 1. The control unit 202 performs the coating operation in either a first mode in which a voltage is applied to the supply roller 5 and the developing roller 4 under different conditions than when the image forming operation is performed, or a second mode in which a voltage is applied to the supply roller 5 and the developing roller 4 under the same conditions as when the image forming operation is performed. In Example 1, an example was shown in which the voltage application in the second mode is performed under the same conditions as when the image forming operation is performed, but the control conditions in the second mode are not limited to this example. In the second mode, the amount of metal soap 45c supplied from the developing roller 4 to the surface of the photoreceptor 1 should be less than in the first mode. For example, the potential difference ΔVr may be set to a common polarity in both the first and second modes such that an electrostatic force acts on the metal soap 45c in the direction from the supply roller 5 to the developing roller 4, and the absolute value of the potential difference ΔVr may be set to be smaller in the second mode than in the first mode. In this case as well, the amount of metal soap 45c supplied in the first mode is increased, which suppresses the increase in torque of the photoreceptor 1, and the amount of metal soap 45c supplied in the second mode is decreased, which suppresses the coating of the electrostatic roller. Furthermore, the potential difference of the polarity that applies an electrostatic force to the metal soap 45c in the direction from the supply roller 5 to the developing roller 4 only needs to be smaller in the second mode than in the first mode. As a result, in the second mode The amount of metal soap 45c supplied is less than the amount of metal soap 45c supplied in the first mode. For example, if the potential difference ΔVr in the first mode is polarity such that an electrostatic force acts on the metal soap 45c in the direction from the supply roller 5 to the developing roller 4, and the potential difference ΔVr in the second mode is polarity opposite, then the conditions do not have to be the same as during image formation. In this case as well, the potential difference ΔVr in the second mode can be said to be smaller than the potential difference ΔVr in the first mode, as it is the potential difference polarity such that an electrostatic force acts on the metal soap 45c in the direction from the supply roller 5 to the developing roller 4.

[0079] Furthermore, when the difference between the surface potential of the photoreceptor 1 charged by the charging roller 2 and the development voltage applied to the developing roller 4 is defined as the back contrast, the back contrast during the coating operation may be controlled to be greater than the back contrast during the image formation operation. By controlling the applied voltages to the charging roller 2 and the developing roller 4 in this way, the metal soap 45c is efficiently transferred to the photoreceptor 1 during the coating operation. In addition, the back contrast may be controlled so that the amount of metal soap 45c supplied from the developing roller 4 to the surface of the photoreceptor 1 is less in the second mode than in the first mode. Specifically, the applied voltages to the charging roller 2 and the developing roller 4 may be controlled so that the back contrast is smaller in the second mode than in the first mode. This allows for efficient supply of metal soap 45c in the first mode, suppressing an increase in the torque of the photoreceptor 1, and reduces the amount of metal soap 45c supplied in the second mode, thereby suppressing coating by the charging roller.

[0080] Figure 6 shows the results of measuring the amount of metal soap 45c transferred to the surface of the photoreceptor 1 for various ΔVr values ​​using a scanning X-ray photoelectron spectroscopy analyzer. When Vrs is on the positive polarity side of Vdc (first mode), ΔVr is large on the negative polarity side (small in value). It can be seen that the amount of metal soap 45c transferred increases in this case. The method for measuring the amount of metal soap 45c transferred to the photoreceptor 1 is described below. A fragment of the photoreceptor 1 is cut out from the photoreceptor 1 after the metal soap coating operation has been performed for various ΔVr values. The elemental concentration value of zinc (Zn) is calculated by measuring the surface of this fragment of photoreceptor 1 with a scanning X-ray photoelectron spectroscopy analyzer, and the amount of metal soap 45c transferred is calculated. The measurement conditions for the scanning X-ray photoelectron spectroscopy analyzer are as follows.

[0081] Analyzer: Scanning X-ray photoelectron spectrometer (ESCA system ULVAC PHI 5700 (manufactured by ULVAC-PHI)) Vacuum degree: 3.99×10 -5 Pa or less X-ray source: Mg source Scan: Narrow scan Measured elements: C1s, O1s, Mg2s, Si2p, Zn2p3 X-ray incident angle: 45 degrees Measurement method: Measurements were taken at any one location in both the area irradiated with an electron beam or ultraviolet light with a wavelength of 125-260 nm and the area not irradiated with an electron beam or ultraviolet light. Analysis software used: PHI MultiPak (trademark) (manufactured by ULVAC-PHI). With smoothing correction: Point9 and background correction: OFF SET, the spectra of each element were displayed, and elemental concentration values ​​(atom%) were calculated from the spectral area obtained by subtracting the baseline. 8. Control procedure for metal soap application operation

[0082] Next, the control procedure for the metal soap coating operation will be explained with reference to the flowchart in Figure 5. In Example 1, the metal soap coating operation is performed by the control unit 202. The timing of the metal soap coating operation will be explained using the case where it is performed after the image forming operation as an example.

[0083] When the image forming apparatus 100 is ready for image forming and a print signal is input by the user (S1), it performs the image forming operation (S2). When the image forming operation is completed, the developing roller 4 The device is separated from the photoreceptor 1 to stop the drive and turn off various voltages (S3).

[0084] Next, it is determined whether the cumulative number of prints since the last metal soap coating operation is equal to or greater than a predetermined number (S5). If the cumulative number of prints is equal to or greater than the first threshold, the process proceeds to S7. If the cumulative number of prints is less than the first threshold, the process proceeds to the torque detection operation of the drive motor of the photoreceptor 1 (S5). In Example 1, the predetermined number was set to 500. The predetermined number is just an example and is not limited to this value; it can be set appropriately according to the equipment configuration, required accuracy, etc. The cumulative number of prints can also be counted by recording the rotation speed of the photoreceptor 1. The rotation speed of the photoreceptor 1 is stored in the cartridge memory 300, which serves as the first recording unit. The cartridge memory 300 is provided in the photoreceptor unit 13 of the process cartridge 7, and information is input and output via the cartridge memory communication mechanism 52.

[0085] The torque detection mechanism 51, acting as the torque detection unit, determines whether the torque value of the drive motor of the photoreceptor 1 is greater than or equal to a second threshold (S6). If the torque value is greater than or equal to the second threshold, the process proceeds to the metal soap application operation (S7). If the torque value is less than the second threshold, the printing operation is terminated (S14). In Example 1, the predetermined torque threshold was set to 2.0 kgf·cm. The torque threshold value is an example and is not limited to this value; it can be set appropriately according to the equipment configuration, required accuracy, etc.

[0086] When the metal soap coating operation starts (S7), the usage history is checked via the cartridge memory communication mechanism 52 (S8). The usage history of the process cartridge 7 is recorded in the cartridge memory 300, which is a non-volatile memory attached to the photoreceptor unit 13. As part of the usage history of the process cartridge 7, information such as the total number of prints of the process cartridge 7 is recorded in the cartridge memory 300, which acts as a second recording unit. The total number of prints of the cartridge 7 can be counted by recording the total number of rotations of the photoreceptor 1.

[0087] Next, it is determined whether the total number of prints from the process cartridge 7 is equal to or greater than a third threshold (S91). The third threshold is used to determine whether the process cartridge 7 is in the early stages of use or in the middle of its lifespan, and is set appropriately according to the configuration of the process cartridge 7 and the required control accuracy. If the total number of prints is less than the third threshold, the first mode is selected (S92), and if the total number of prints is equal to or greater than the third threshold, the second mode is selected (S93). Depending on the selected operating mode, the charging voltage, developing voltage, developing blade voltage, and supply voltage are applied, and the driving of the developing roller 4 and the photoreceptor 1 is started, bringing the developing roller 4 into contact with the photoreceptor 1 and starting the measurement of the metal soap application operation time (T) (S94).

[0088] The metal soap coating operation continues until the metal soap coating operation time T reaches a predetermined time (S10). When the metal soap coating operation time T reaches the predetermined time, the developing roller 4 is separated from the photoreceptor 1, the driving of the developing roller 4 and the photoreceptor 1 is stopped, and the applied voltage is turned OFF (S11). Then the metal soap coating operation is terminated (S12). In Example 1, the predetermined time was set to 5 seconds. The predetermined time T is not limited to 5 seconds and can be set as appropriate.

[0089] Next, it is determined whether there is a request for continuous printing (S13). If there is no request for continuous printing, the process proceeds to the print termination operation (S14). If there is a request for continuous printing, the operations S2 to S13 are repeated until there are no more requests for continuous printing.

[0090] The metal soap coating operation in S7 may be performed immediately after the image forming operation in S2, without the separation operation of the developing roller 4 in S3, the stopping of the drive, or the turning off of various voltages.

[0091] Furthermore, the metal soap application operation in S7 may be performed during the initial operation check control that is executed for the first time after a new cartridge is installed.

[0092] 9. Verification of the effects of Example 1 (effect of two modes for metal soap application operation) In the aforementioned Example 1, we investigated whether it was possible to suppress the increase in torque due to the adhesion of discharge products to the surface of the photoreceptor 1 and the occurrence of charging roller coating, where metal soap covers the charging roller 2, using Example 1 and a comparative example. For the investigation, a low-intermittent print durability test was performed on 50,000 sheets under low-temperature and low-humidity conditions (temperature 15°C, humidity 10%) where charging roller coating is likely to occur. In this low-intermittent print durability test, a horizontal line with an image ratio of 1% was printed on the recorded image, and 400g of toner was filled.

[0093] In Example 1, the metal soap coating operation was performed in the first mode initially, and in the second mode from the middle of the process onward.

[0094] Comparative Example 1 involved performing the metal soap coating operation only in the first mode. Comparative Example 2 involved performing the metal soap coating operation only in the second mode.

[0095] <Verification Result 1> Table 2 shows the verification results. [Table 2]

[0096] In Example 1, no torque increase or image defects due to coating of the electrostatic roller occurred up to 50,000 sheets. On the other hand, in Comparative Example 1, there was no initial torque increase or coating of the electrostatic roller, but at 40,000 sheets, a large amount of metal soap 45c adhered to the electrostatic roller 2, and numerous vertical streaks occurred due to charging defects caused by the coating of the electrostatic roller.

[0097] In Comparative Example 2, the torque increased slightly in the initial stages, and a large amount of toner 10 that had slipped through the cleaning blade 8 adhered to the charging roller 2. This resulted in poor charging due to the coating of the charging roller, causing numerous vertical streaks. At the 10,000-sheet mark, the torque stabilized and the coating of the charging roller stopped progressing, but the initial effects caused vertical streaks to persist until 50,000 sheets.

[0098] In this verification, by selecting the first mode initially and the second mode in the middle of the process cartridge 7's usage for the metal soap application operation in Example 1, it was possible to suppress both the increase in torque due to the metal soap and the suppression of the coating on the electrostatic roller until the end of its lifespan.

[0099] (Example 2) In Example 2, as one method for more effectively applying metal soap during the metal soap application operation of Example 1, the optimal range for the surface movement speed difference between the surface of the developing roller 4 and the surface of the photoreceptor 1 is described.

[0100] 1. Surface movement speed during metal soap application operation When the developing roller 4 comes into contact with the photoreceptor 1, a developing nip is formed in the developing section. By creating a difference in surface movement speed between the surface of the developing roller 4 and the surface of the photoreceptor 1, the toner 10 rotates in the developing nip section and supplies metal soap 45c to the photoreceptor 1. The ratio of the surface movement speed of the developing roller 4 to the surface movement speed of the photoreceptor 1 is called the DD peripheral speed ratio. Increasing the DD peripheral speed ratio increases the rolling of the toner 10, which increases the opportunities for contact between the metal soap 45c and the photoreceptor 1, making transfer easier and thus making it easier to form a film of metal soap 45c on the surface of the photoreceptor 1. For this reason, it is desirable to have a large difference between the surface movement speed of the developing roller 4 and the surface movement speed of the photoreceptor 1 for efficient metal soap application.

[0101] In fact, when the amount of metal soap 45c transferred to the surface of the photoreceptor 1 was measured, it was found that the amount of metal soap 45c transferred increased as the DD peripheral speed ratio increased, as shown in Figure 7. The amount of metal soap 45c transferred to the surface of the photoreceptor 1 was measured using a scanning X-ray photoelectron spectroscopy analyzer, similar to Example 1.

[0102] Furthermore, the index representing the difference in surface movement speed between the surface of the photoreceptor 1 and the surface of the developing roller 4 is not limited to the DD peripheral speed ratio; the difference in surface movement speed (DD peripheral speed difference) may also be used. Methods for changing the DD peripheral speed ratio or DD peripheral speed difference include changing the rotation speed of the developing roller 4 or changing the rotation speed of the photoreceptor 1.

[0103] However, it has been found that if the image forming operation is constantly performed with a high DD peripheral speed ratio, the toner 10 is prone to deterioration and background fogging occurs, where toner adheres to the non-image areas of the photoreceptor 1 (the surface of the photoreceptor where the dark area potential Vd is formed).

[0104] Regarding the degradation of toner 10, an excessive supply of metal soap 45c occurs initially, leading to depletion of metal soap 45c from the developing chamber 3a and toner storage unit 3b. In addition, the number of times toner 10 is rubbed increases, causing toner 10 to degrade and resulting in a decrease in its electrostatic properties.

[0105] Regarding background fogging, if the toner 10 rolls too much, the charge of the toner 10 is more likely to escape, reducing the charge of the toner 10. As a result, the toner 10 develops onto the photoreceptor 1 as fogging, and in the initial state where cleaning performance is unstable, cleaning may not be performed properly. Therefore, in Example 2, as shown in Figure 8, the rotation speed of the photoreceptor 1 and the developing roller 4 is controlled so that the DD peripheral speed ratio during the coating operation is between 85% and 115% so that the fogging value on the photoreceptor 1 is 0.5% or less. In addition, a configuration in which the DD peripheral speed ratio during the coating operation is between 70% and 180% so that the fogging value on the photoreceptor 1 is 1.0% or less is also possible, but a DD peripheral speed ratio of 85% to 115% as in Example 2 is particularly preferred.

[0106] Furthermore, similar to Example 1, a charging voltage is applied to control the photoreceptor 1 to a dark area potential Vd, and the development voltage is set to the same as during the image formation operation, thereby performing so-called solid white printing.

[0107] 2. Verification of the effect of Example 2 (effect of increasing DD peripheral speed ratio from 85% to 115%) In the aforementioned Example 2, we investigated whether it was possible to suppress the increase in torque due to the adhesion of discharge products to the surface of the photoreceptor 1 and the occurrence of charging roller coating, where metal soap covers the charging roller 2, using Example 2 and a comparative example. The investigation was conducted under the same conditions as in Example 1.

[0108] In Example 2, the DD peripheral speed ratio during the metal soap coating operation was set to 115%. Comparative Example 3 had the DD peripheral speed ratio set to 75% during the metal soap coating operation. Comparative Example 4 had the DD peripheral speed ratio set to 125% during the metal soap coating operation.

[0109] <Verification Result 2> Table 3 shows the verification results. [Table 3]

[0110] In Example 2, the torque did not increase up to 50K, and no image defects due to the coating of the charging roller occurred. On the other hand, in Comparative Examples 3 and 4, the toner 10 developed on the photoreceptor 1 as fogging slipped through the cleaning blade 8, and a large amount of toner 10 adhered to the charging roller 2, resulting in numerous vertical streaks due to charging defects caused by the coating of the charging roller. At the midpoint of 10K, the progression of the coating of the charging roller stopped, but the vertical streaks continued to appear up to 50K due to the initial effects.

[0111] As explained above, by setting the DD peripheral speed ratio during the metal soap coating operation within the range of 85% to 115% as described in Example 2, it has been shown that both suppression of torque increase due to metal soap and suppression of coating on the charging roller can be achieved until the end of the lifespan. The DD peripheral speed ratio may also be controlled so that it is greater during the metal soap coating operation than during the image forming operation. For example, by setting the DD peripheral speed ratio during the metal soap coating operation to 115% and the DD peripheral speed ratio during normal image forming operation to 90%, efficient application of metal soap during the metal soap coating operation and suppression of fogging during image forming can be achieved simultaneously. Furthermore, the DD peripheral speed ratio may be controlled so that the amount of metal soap 45c supplied from the developing roller 4 to the surface of the photoreceptor 1 is less in the second mode than in the first mode. Specifically, the rotational speeds of the photoreceptor 1 and the developing roller 4 may be controlled so that the ratio of the surface movement speed of the developing roller 4 to the surface movement speed of the photoreceptor 1 is smaller in the second mode than in the first mode. This allows for efficient supply of the metal soap 45c in the first mode, thereby suppressing an increase in the torque of the photoreceptor 1, and also reduces the amount of metal soap 45c supplied in the second mode, thereby suppressing coating of the electrostatic roller.

[0112] (Example 3) In Example 3, a method for controlling the pre-exposure unit 27 is described as a way to more effectively apply metal soap during the metal soap application operation of Example 1. 1. Control method for the pre-exposure unit during metal soap coating operation

[0113] During the metal soap coating operation, it is preferable to reduce the exposure amount of the pre-exposure unit 27 compared to the image forming operation, and it is especially preferable to turn it OFF (prevent exposure by the pre-exposure unit 27). By reducing the pre-exposure amount, residual charge remains on the surface of the photoreceptor 1 due to the remaining charge that has not been discharged. Therefore, the electrical adhesion force of the positively polarized metal soap 45c, which has the opposite polarity to the normal polarity of the toner 10, to the photoreceptor 1 becomes stronger, making it difficult for it to peel off the surface of the photoreceptor 1. In this state, when the metal soap 45c on the photoreceptor 1 passes over the cleaning blade 8 and the developing roller 4, the metal soap 45c is physically pressed into the photoreceptor 1 and adheres firmly. In other words, by reducing the pre-exposure amount compared to the image forming operation, the retention ability of the metal soap 45c to the photoreceptor 1 during the metal soap coating operation is increased, and the metal soap 45c can adhere firmly to the photoreceptor 1. On the other hand, increasing the exposure amount to the surface of the photoreceptor 1 weakens the electrical adhesion of the positively polarized metal soap 45c to the photoreceptor 1, making it easier for it to peel off the surface of the photoreceptor 1.

[0114] When the torque of the photoreceptor 1 was measured under several conditions with different pre-exposure amounts, it was confirmed that the torque decreased when the pre-exposure amount was reduced, as shown in Figure 9. <Pre-exposure conditions> [Table 4]

[0115] 2. Verification of the effect of Example 3 (effect of reducing pre-exposure dose) Under the same conditions as in Example 1, durability testing was conducted to check for any other adverse effects. In Example 3, the pre-exposure amount during the metal soap coating operation was turned OFF (= 0 μJ / cm²). 2 I set it to ).

[0116] <Verification Result 3> Table 5 shows the verification results. [Table 5]

[0117] In Example 3, compared to Example 1, a reduction in initial torque was achieved, and no image defects occurred until the end of the product's lifespan.

[0118] As explained above, it has been shown that torque can be reduced, especially in the initial state, by adding control to reduce the exposure amount of the pre-exposure unit 27 during the metal soap coating operation. Alternatively, the pre-exposure unit 27 may be controlled so that the amount of metal soap 45c supplied from the developing roller 4 to the surface of the photoreceptor 1 is less in the second mode than in the first mode. Specifically, the pre-exposure unit 27 may be controlled so that the exposure amount of the pre-exposure unit 27 is greater in the second mode than in the first mode. Furthermore, exposure by the pre-exposure unit 27 may be omitted in the first mode, while exposure by the pre-exposure unit 27 may be performed in the second mode. This allows for efficient supply of metal soap 45c in the first mode, suppressing the torque increase of the photoreceptor 1, and reduces the amount of metal soap 45c supplied in the second mode, thereby suppressing coating of the charging roller.

[0119] (Example 4) In Example 4, a method for controlling the intermediate transfer belt 31 is described as a way to more effectively apply metal soap during the metal soap application operation of Example 1. 1. Control method for the intermediate transfer belt during metal soap application operation

[0120] During the metal soap coating operation, if the intermediate transfer belt 31 can be separated, separating the intermediate transfer belt 31 can suppress the recovery of the metal soap 45c from the intermediate transfer belt 31 by physical adhesion. In addition, by setting the primary transfer high voltage 73 to 0V, it is possible to reduce the amount of metal soap 45c recovered from the intermediate transfer belt 31 by electrostatic adhesion.

[0121] 2. Verification of the effect of Example 4 (effect of intermediate transfer belt separation) Under the same conditions as in Example 1, durability testing was conducted to confirm the effect on torque reduction. In Example 4, the intermediate transfer belt 31 was separated during the metal soap coating operation.

[0122] <Verification Result 4> Table 6 shows the verification results. [Table 6]

[0123] In Example 4, compared to Example 1, torque was consistently reduced from the beginning to the end of the lifespan, and no other image defects occurred.

[0124] As explained above, torque could be reduced by adding control to separate the intermediate transfer belt 31 during the metal soap coating operation or to set the primary transfer high pressure 73 to 0V. In Example 4, an example was shown in which the primary transfer high pressure 73 was set to 0V when the coating operation was performed, but the example is not limited to this example. The primary transfer high pressure 73 should be controlled so that the potential difference that acts an electrostatic force on the metal soap 45c formed between the photoreceptor 1 and the intermediate transfer belt 31 in the direction from the photoreceptor 1 to the intermediate transfer belt 31 is smaller during the coating operation than during image formation. This reduces the amount of metal soap 45c collected on the intermediate transfer belt 31 when the coating operation is performed. Alternatively, the contact and separation of the intermediate transfer belt 31 may be controlled so that the amount of metal soap 45c supplied from the developing roller 4 to the surface of the photoreceptor 1 is less in the second mode than in the first mode. Specifically, the intermediate transfer belt 31 may be controlled so that it is in contact with the photoreceptor 1 in the first mode and separated from the photoreceptor 1 in the second mode. This allows for efficient supply of metal soap 45c in the first mode, suppressing an increase in the torque of the photoreceptor 1, and reduces the amount of metal soap 45c supplied in the second mode, thereby suppressing coating of the electrostatic roller. Alternatively, the primary transfer pressure 73 may be controlled so that the amount of metal soap 45c supplied from the developing roller 4 to the surface of the photoreceptor 1 is less in the second mode than in the first mode. Specifically, the primary transfer pressure 73 may be controlled so that the potential difference formed between the photoreceptor 1 and the intermediate transfer belt 31, which causes an electrostatic force to act on the metal soap 45c in the direction from the photoreceptor 1 to the intermediate transfer belt 31, is greater in the second mode than in the first mode. This allows for efficient supply of the metal soap 45c in the first mode, thereby suppressing an increase in the torque of the photoreceptor 1, and also reduces the amount of metal soap 45c supplied in the second mode, thereby suppressing coating of the electrostatic roller.

[0125] (Example 5) In Example 5, the metal soap coating operation (initial supply operation) and the control of the DD peripheral speed ratio during the initial operation of loading the process cartridge 7 containing the new photoreceptor 1 into the image forming apparatus 100 and transitioning it to a printable state will be described.

[0126] 1. Control method for metal soap application operation and DD peripheral speed ratio during initial operation During the initial operation, the same voltage as in the first mode described in Example 1 is applied to perform the metal soap coating operation. When performing the metal soap coating operation, the DD peripheral speed ratio is increased compared to when performing the normal image forming operation. That is, if the DD peripheral speed ratio during the metal soap coating operation is the first peripheral speed ratio and the DD peripheral speed ratio during the image forming operation is the second peripheral speed ratio, the first peripheral speed ratio is made larger than the second peripheral speed ratio. This allows the metal soap to be transferred to the photoreceptor 1 more effectively, increasing the amount of metal soap applied from the developing roller 4 to the photoreceptor 1, and allowing the torque of the photoreceptor 1 to be reduced more quickly. Note that the other configurations of Example 5 are the same as in Example 1, so their description is omitted.

[0127] 2. Verification of the effects of Example 5 In Example 5, the voltage of the first mode was applied during the initial operation, and the metal soap coating operation was performed with Vdc = -300V, Vrs = -100V, and ΔVr = -200V. The DD peripheral speed ratio (first peripheral speed ratio) during the metal soap coating operation during the initial operation was set to 115% in Example 5 and 90% in Comparative Example 5, and the torque reduction effect and the presence or absence of image defects immediately after the completion of the initial operation were checked. Here, image defects refer to vertical streaks in the image caused by the charging roller coating, where the metal soap covers the charging roller 2. The DD peripheral speed ratio (second peripheral speed ratio) during the image formation operation after the completion of the initial operation was set to 90%.

[0128] <Verification Result 5> Table 7 shows the verification results. [Table 7]

[0129] In Example 5, the torque of the photoreceptor 1 immediately after initial operation was reduced more significantly compared to Comparative Example 5, and no image defects occurred.

[0130] Table 8 also shows the change in the torque value of the photoreceptor 1 before and after the initial operation. [Table 8]

[0131] In Example 5, the torque of the photoreceptor 1 was reduced even further compared to Comparative Example 5.

[0132] Furthermore, a higher DD peripheral speed ratio during initial operation results in a larger amount of metal soap being applied, allowing the torque to decrease more quickly. However, it is desirable to set the upper limit of the DD peripheral speed ratio to 180%. This is because, as explained in Example 2, if the DD peripheral speed ratio is increased too much, the electrostatic properties of the toner 10 decrease, and the amount of toner 10 developed as fogging on the photoreceptor 1 increases. In particular, with a new process cartridge 7 whose cleaning properties are unstable, the amount of fogging supplied to the photoreceptor 1 increases. When the amount of toner increases, cleaning cannot adequately remove the toner fouling, leading to poor charging due to inadequate cleaning and resulting in image defects. In Example 5, by setting the DD peripheral speed ratio to 115% during the metal soap application operation in the initial operation, it was possible to achieve both torque reduction due to metal soap application to the photoreceptor 1 and suppression of toner fouling. The DD peripheral speed ratio was set to 90% when the image forming operation was performed after the initial operation was completed.

[0133] As explained above, by increasing the DD peripheral speed ratio during the initial metal soap coating operation performed when a new process cartridge 7 is installed in the image forming apparatus 100, the torque of the photoreceptor 1 can be reduced more quickly than during the image forming operation. In addition, the transition from an unstable state of cleaning performance when new to a stable state can be made more quickly. Furthermore, in the control of Example 5, the torque of the photoreceptor 1 can be reduced more quickly without increasing the peripheral speed of the photoreceptor 1, while suppressing the increase in load on the motor driving the photoreceptor 1. In addition, since the time required for the initial operation can be shortened, the waiting time from when a new process cartridge 7 is installed in the image forming apparatus 100 until printing is possible can be reduced, improving convenience for the user.

[0134] In Example 5, the DD peripheral speed ratio may be increased for the entire duration of the initial operation, or it may be increased for at least a portion of the duration of the initial operation. In either case, it has the effect of reducing the torque of the photoreceptor 1 more quickly.

[0135] Furthermore, in Example 5, control was described to increase the DD peripheral speed ratio during the period when the metal soap coating operation is performed during the initial operation. However, the DD peripheral speed ratio may be increased not only during the metal soap coating operation, but also during the initial operation (periods other than when the metal soap coating operation is performed).

[0136] For example, it is advisable to set the DD peripheral speed ratio during initial operation to a value greater than 100% (e.g., 115%). When the process cartridge 7 is new, there is less toner interposed between the photoreceptor 1 and the cleaning blade 8, which acts as a lubricant, resulting in particularly high torque for the photoreceptor 1. By setting the DD peripheral speed ratio (first peripheral speed ratio) during initial operation to a value greater than 100% and bringing the developing roller 4 into contact with the photoreceptor 1, the developing roller 4, which rotates faster than the photoreceptor 1, can assist the rotation of the photoreceptor 1. This reduces the torque of the photoreceptor 1 and the load on the drive motor for the photoreceptor 1, thereby suppressing the initial operation from stopping due to a temporary excessive load on the motor. Furthermore, it is advisable to set the DD peripheral speed ratio (second peripheral speed ratio) during the image formation operation to a value of 100% or less (e.g., 90%). This suppresses fogging during image formation. Examples of control methods used include increasing the first peripheral speed ratio during initial operation, making the first peripheral speed ratio during initial operation greater than the second peripheral speed ratio during image forming operation, making the first peripheral speed ratio greater than 100%, and making the second peripheral speed ratio less than or equal to 100%. The torque reduction and fouling suppression effects of these controls are obtained independently of the presence or absence of metal soap contained in the toner.

[0137] Furthermore, consider the case where, for example, the voltage applied during image formation is used instead of the voltage applied during the first mode of metal soap coating operation during initial operation. The applied voltage for the first mode is, for example, Vdc=-300V, Vrs=-100V, ΔVr=-200V. The applied voltage during image formation is, for example, Vdc=-300V, Vrs=-350V, ΔVr=+50V. In this case, by increasing the DD peripheral speed ratio (first peripheral speed ratio), as explained in Example 2, the amount of toner developed as fogging on the photoreceptor 1 increases slightly, and the amount of fogging toner that reaches the cleaning blade 8 also increases. Since inorganic silicon 45b is added to the toner 10, the amount of inorganic silicon 45b adhering to the photoreceptor 1 also increases slightly as the amount of fogging toner adhering to the photoreceptor 1 increases. The inorganic silicon 45b passes through the cleaning blade 8 appropriately, thereby appropriately reducing the frictional resistance between the photoreceptor 1 and the cleaning blade 8. By increasing the ratio (first peripheral speed ratio), the torque of the photoreceptor 1 can be reduced more quickly. The effect of reducing the torque of the photoreceptor 1 by applying the same voltage as during the image forming operation during the initial operation to increase the DD peripheral speed ratio (first peripheral speed ratio) is an effect that can be obtained independently of the presence or absence of metal soap contained in the toner.

[0138] Furthermore, consider the case where the contact member provided to contact the developing roller 4 contains a fluorine-based low-friction substance such as Teflon®. In an image forming apparatus with such a configuration, increasing the DD peripheral speed ratio (first peripheral speed ratio) during initial operation allows the low-friction substance to be transferred from the contact member to the developing roller 4 more quickly, and further, to the photoreceptor 1 more quickly. Therefore, the torque of the photoreceptor 1 can be reduced more quickly. As an example of such a contact member, there is a sealing member that contacts the developing roller 4 at its longitudinal end to prevent toner from leaking out of the developing chamber 3a. There is also a sealing member that has a sheet-like member provided to contact the developing roller 4 along its entire longitudinal direction, preventing toner from leaking out of the developing chamber 3a. In a configuration having a sealing member or sheet member that contacts the developing roller 4, the torque reduction effect of the photoreceptor 1 achieved by controlling the DD peripheral speed ratio (first peripheral speed ratio) to increase during the initial operation is an effect that can be obtained independently of the presence or absence of metal soap contained in the toner.

[0139] Furthermore, the torque of the photoreceptor 1 during initial operation may be detected, and if the torque exceeds a certain threshold, the DD peripheral speed ratio may be increased. For example, if the detected torque value is greater than or equal to a fourth threshold, the DD peripheral speed ratio during initial operation (first peripheral speed ratio) may be made greater than the DD peripheral speed ratio during image formation operation (second peripheral speed ratio). By appropriately controlling the torque according to the situation in this way, the motor load on the developing roller 4 can be reduced.

[0140] Furthermore, during initial operation, as in Example 3, the exposure amount of the pre-exposure unit 27 may be reduced compared to the image forming operation, or it may be turned OFF (no exposure by the pre-exposure unit 27). By reducing the pre-exposure amount, residual charge remains on the surface of the photoreceptor 1 due to the remaining charge that was not removed. Therefore, the electrical adhesion force of the positively polarized metal soap 45c to the photoreceptor 1, which is the opposite polarity to the normal polarity of the toner 10, becomes stronger, making it less likely to peel off the surface of the photoreceptor 1. As a result, the metal soap 45c is more easily retained on the photoreceptor 1, and the torque of the photoreceptor 1 can be reduced more quickly.

[0141] Furthermore, during the initial operation, as in Example 4, if the photoreceptor 1 and the intermediate transfer belt 31 can move in and out of contact, separating the intermediate transfer belt 31 can suppress the transfer of metal soap 45c to the intermediate transfer belt 31 by physical adhesion. Therefore, the torque of the photoreceptor 1 can be reduced more quickly. Also, even if the photoreceptor 1 and the intermediate transfer belt 31 are in contact during the initial operation, setting the primary transfer high voltage 73 to 0V can reduce the amount of metal soap 45c that transfers to the intermediate transfer belt 31. Therefore, the torque of the photoreceptor 1 can be reduced more quickly.

[0142] Furthermore, while Example 5 describes a process cartridge 7 in which the developing unit 3 and the photoreceptor unit 13 are integrated, the method is not limited to this configuration. For example, in a configuration where only the photoreceptor unit 13 is in a cartridge, applying Example 5 to the initial operation performed by the photoreceptor unit 13 when it is new can reduce the torque of the photoreceptor 1 more quickly.

[0143] Examples 1-5 used inverse development, but are not limited to this, and normal development may also be used. Examples 1-5 used a negatively charged photoreceptor 1, but are not limited to this, and a positively charged photoreceptor may also be used. Also, Examples 1-5 used a color laser printer as the image forming apparatus 100, but an image forming apparatus 100 having a single cartridge configuration, such as a monochrome laser printer, may also be used. Instead of an intermediate transfer method, a method may be used in which the toner image formed on the surface of the photoreceptor 1 is directly transferred to the recording material S. Furthermore, the setting conditions used for explanation in Examples 1 to 5 are examples only and are not limited to those conditions.

[0144] This embodiment includes the following configurations and methods. (Composition 1) A rotatable image carrier, A developing member in a developing section facing the image carrier supplies toner to the surface of the image carrier to form a toner image, A supply member that supplies the toner to the developing member, A control unit that performs an image forming operation for forming the toner image on the recording material, and a metal soap supply operation for supplying a metal soap with the opposite polarity to the toner contained in the toner from the developing member to the surface of the image carrier when not forming an image, It has, The image forming apparatus is characterized in that the operating modes of the metal soap supply operation include a first mode and a second mode, and the potential difference that causes an electrostatic force to act on the metal soap in the direction from the supply member to the developing member, formed between the supply member and the developing member, is smaller when the metal soap supply operation of the second mode is performed than when the metal soap supply operation of the first mode is performed. (Configuration 2) The image forming apparatus according to configuration 1, wherein the polarity of the potential difference formed between the supply member and the developing member is reversed when the metal soap supply operation is performed in the first mode and when the metal soap supply operation is performed in the second mode. (Composition 3) The image forming apparatus according to configuration 1 or 2, wherein the potential difference formed between the supply member and the developing member is the same when the metal soap supply operation of the second mode is performed and when the image forming operation is performed. (Composition 4) The image forming apparatus according to any one of configurations 1 to 3, wherein the ratio of the surface movement speed of the developing member to the surface movement speed of the image carrier is greater when the metal soap supply operation is performed than when the image forming operation is performed. (Composition 5) The image forming apparatus according to any one of configurations 1 to 4, wherein the back contrast, which is the difference between the surface potential of the image carrier in the developing unit and the developing voltage applied to the developing member, is greater when the metal soap supply operation is performed than when the image forming operation is performed. (Composition 6) The system further comprises a transfer member facing the image carrier via an intermediate transfer body that can come into contact with and separate from the image carrier, The image forming apparatus according to any one of configurations 1 to 5, wherein the intermediate transfer body separates from the image carrier when the metal soap supply operation is performed. (Composition 7) The system further comprises a transfer member facing the image carrier via an intermediate transfer body that can come into contact with and separate from the image carrier, The image forming apparatus according to any one of configurations 1 to 6, wherein the potential difference that causes an electrostatic force to act on the metal soap in the direction from the image carrier to the transfer member, formed between the image carrier and the transfer member, is smaller when the metal soap supply operation is performed than when the image forming operation is performed. (Composition 8) The image forming apparatus according to configuration 7, wherein the applied voltage to the transfer member is 0V when the metal soap supply operation is performed. (Composition 9) A charging member that charges the surface of the image carrier, An exposure unit that exposes the surface of the image carrier upstream of the charging section by the charging member, Furthermore, The image forming apparatus according to any one of configurations 1 to 8, wherein the exposure amount of the exposure unit is smaller when the metal soap supply operation is performed than when the image forming operation is performed. (Composition 10) The image forming apparatus according to configuration 9, wherein exposure by the exposure unit is not performed when the metal soap supply operation is performed. (Composition 11) A rotatable image carrier, A developing member in a developing section facing the image carrier supplies toner to the surface of the image carrier to form a toner image, A supply member that supplies the toner to the developing member, A control unit that performs an image forming operation for forming the toner image on a recording material, and a metal soap supply operation for supplying the toner from the developing member to the surface of the image carrier when not forming an image, thereby applying a metal soap with the opposite polarity to the toner contained in the toner to the surface of the image carrier, It has, The image forming apparatus is characterized in that the operating modes of the metal soap supply operation include a first mode and a second mode, and the amount of metal soap supplied from the developing member to the surface of the image carrier is less when the metal soap supply operation in the second mode is performed than when the metal soap supply operation in the first mode is performed. (Composition 12) The image forming apparatus according to configuration 11, wherein the potential difference that causes an electrostatic force to act on the metal soap in the direction from the supply member to the developing member, formed between the supply member and the developing member, is smaller when the metal soap supply operation of the second mode is performed than when the metal soap supply operation of the first mode is performed. (Composition 13) The image forming apparatus according to configuration 11 or 12, wherein the polarity of the potential difference formed between the supply member and the developing member is reversed when the metal soap supply operation is performed in the first mode and when the metal soap supply operation is performed in the second mode. (Composition 14) The image forming apparatus according to any one of the configurations 11 to 13, wherein the ratio of the surface movement speed of the developing member to the surface movement speed of the image carrier is smaller when the metal soap supply operation of the second mode is performed than when the metal soap supply operation of the first mode is performed. (Composition 15) The image forming apparatus according to any one of the configurations 11 to 14, wherein the back contrast, which is the difference between the surface potential of the image carrier in the developing unit and the developing voltage applied to the developing member, is smaller when the metal soap supply operation in the second mode is performed than when the metal soap supply operation in the first mode is performed. (Composition 16) The system further comprises a transfer member facing the image carrier via an intermediate transfer body that can come into contact with and separate from the image carrier, The image forming apparatus according to any one of the configurations 11 to 15, wherein the intermediate transfer body is in contact with the image carrier when the first mode of metal soap supply operation is performed, and the intermediate transfer body is separated from the image carrier when the second mode of metal soap supply operation is performed. (Composition 17) A transfer member facing the image carrier via an intermediate transfer body that can move in and out of contact with the image carrier. Furthermore, The image forming apparatus according to any one of configurations 11 to 16, wherein the potential difference that causes an electrostatic force to act on the metal soap in the direction from the image carrier to the transfer member, formed between the image carrier and the transfer member, is greater when the metal soap supply operation of the second mode is performed than when the metal soap supply operation of the first mode is performed. (Composition 18) A charging member that charges the surface of the image carrier, An exposure unit that exposes the surface of the image carrier upstream of the charging section by the charging member, Furthermore, The image forming apparatus according to any one of configurations 11 to 17, wherein the exposure amount of the exposure unit is greater when the metal soap supply operation in the second mode is performed than when the metal soap supply operation in the first mode is performed. (Composition 19) The image forming apparatus according to configuration 18, wherein exposure by the exposure unit is not performed when the metal soap supply operation of the first mode is performed. (Composition 20) The system further includes a torque detection unit for detecting the driving torque of the image carrier, The image forming apparatus according to any one of configurations 1 to 19, wherein the control unit executes the metal soap supply operation when the number of rotations of the image carrier since the last execution of the metal soap supply operation is equal to or greater than a first threshold, or when the torque value detected by the torque detection unit is equal to or greater than a second threshold. (Composition 21) The control unit, If the total number of rotations of the image carrier is less than the third threshold, the metal soap supply operation is performed in the first mode. The image forming apparatus according to any one of configurations 1 to 20, wherein the metal soap supply operation is performed in the second mode when the total number of rotations of the image carrier is equal to or greater than a third threshold. (Composition 22) The image forming apparatus according to any one of configurations 1 to 21, wherein the ratio of the surface movement speed of the developing member to the surface movement speed of the image carrier is between 85% and 115% when the metal soap supply operation is performed. (Composition 23) A rotatable image carrier, The developing unit, facing the image carrier, includes a developing member that supplies toner to the surface of the image carrier to form a toner image. A control unit that performs an initial operation to transition the image carrier from a new state to a printable state, and an image forming operation to form the toner image on the recording material, It has, An image forming apparatus characterized in that the first peripheral speed ratio, which is the ratio of the surface moving speed of the developing member to the surface moving speed of the image carrier during at least a portion of the execution of the initial operation, is greater than the second peripheral speed ratio, which is the ratio of the surface moving speed of the developing member to the surface moving speed of the image carrier during the execution of the image forming operation. (Composition 24) The image forming apparatus according to configuration 23, wherein the first peripheral speed ratio is greater than 100%. (Composition 25) The image forming apparatus according to configuration 23 or 24, wherein the first peripheral speed ratio is greater than 100%, and the second peripheral speed ratio is 100% or less. (Composition 26) During the execution of the initial operation, the supply member and the developing unit supply the toner to the developing member. An image forming apparatus according to any one of configurations 23 to 25, which forms a potential difference between the material and the toner, causing an electrostatic force to act on the toner in the direction from the supply member to the developing member. (Composition 27) The system further comprises a transfer member facing the image carrier via an intermediate transfer body that can come into contact with and separate from the image carrier, The image forming apparatus according to any one of the configurations 23 to 26, wherein the intermediate transfer body separates from the image carrier when the initial operation described above is performed. (Composition 28) A charging member that charges the surface of the image carrier, The system further comprises an exposure unit that exposes the surface of the image carrier upstream of the charging section by the charging member, The image forming apparatus according to any one of configurations 23 to 27, wherein the exposure amount of the exposure unit is smaller when the initial operation is performed than when the image forming operation is performed. (Composition 29) The image forming apparatus according to configuration 28, wherein exposure by the exposure unit is not performed when the initial operation described above is executed. (Composition 30) The system further includes a torque detection unit for detecting the driving torque of the image carrier, The image forming apparatus according to any one of the configurations 23 to 29, wherein the control unit makes the first peripheral speed ratio greater than the second peripheral speed ratio when the torque value detected by the torque detection unit during the execution of the initial operation is greater than or equal to a fourth threshold. (Composition 31) The development member further comprises a contact member that contacts the surface of the developing member, The image forming apparatus according to any one of configurations 23 to 30, wherein the contact member contains a fluorine-based low-friction substance. (Composition 32) The image forming apparatus according to configuration 31, wherein the contact member is a sealing member that contacts the longitudinal end of the developing member and suppresses toner leakage from the developing member to the outside. (Composition 33) The image forming apparatus according to configuration 31, wherein the contact member has a sheet-like member that is provided to contact the developing member along the longitudinal direction, and is a sealing member that suppresses toner leakage from the developing member to the outside. (Composition 34) The image forming apparatus according to any one of the configurations 23 to 33, characterized in that the toner contains a metal soap having the opposite polarity to the toner. (Composition 35) The image forming apparatus according to configuration 34, wherein the control unit performs an initial supply operation in which it supplies metal soap contained in the toner from the developing member to the surface of the image carrier for at least a portion of the time when the initial operation is performed. (Composition 36) The toner is supplied to the developing member, The image forming apparatus according to configuration 35, wherein the potential difference that causes an electrostatic force to act on the metal soap in the direction from the supply member to the developing member, formed between the supply member and the developing member, is greater during the execution of the initial supply operation than during the execution of the image forming operation. (Composition 37) The system further comprises a transfer member facing the image carrier via an intermediate transfer body that can come into contact with and separate from the image carrier, The potential difference that causes an electrostatic force to act on the metal soap in the direction from the image carrier to the transfer member, formed between the image carrier and the transfer member, is smaller during the execution of the initial operation than during the execution of the image forming operation, according to any one of the configurations 34 to 36. equipment. (Composition 38) The image forming apparatus according to configuration 37, wherein the applied voltage to the transfer member is 0V when the initial operation described above is performed. (Composition 39) The image forming apparatus according to any one of configurations 1 to 22, characterized in that the developing member comes into contact with the image carrier in the developing unit when the metal soap supply operation is performed. (Composition 40) The image forming apparatus according to any one of configurations 23 to 38, characterized in that the developing member comes into contact with the image carrier in the developing unit when the initial operation described above is performed. (Composition 41) The image forming apparatus according to any one of configurations 1 to 22, 36 to 38, characterized in that the metal soap is at least one of zinc, calcium, and magnesium. (Composition 42) The image forming apparatus according to any one of configurations 1 to 22, 36 to 38, characterized in that the metal soap is at least one of zinc stearate, calcium stearate, and magnesium stearate. (Composition 43) The image forming apparatus according to any one of configurations 1 to 22, 36 to 38, characterized in that the metal soap has a particle size of 0.15 μm or more and 2.0 μm or less. (Composition 44) The image forming apparatus according to any one of configurations 1 to 43, characterized in that the image carrier has a protective layer made of acrylic resin on its outermost surface. [Explanation of symbols]

[0145] 1: Photoreceptor, 2: Charging roller, 3b: Toner storage unit, 4: Developing roller, 5: Supply roller, 10: Toner, 45c: Metal soap, 100: Image forming apparatus, 202: Control unit

Claims

1. A rotatable image carrier, a developing member that forms a toner image by supplying toner to the surface of the image carrier in a developing unit facing the image carrier, a supply member that supplies the toner to the developing member, a control unit that executes an image forming operation for forming the toner image on a recording material and a metal soap supply operation for supplying a metal soap having a polarity opposite to that of the toner contained in the toner from the developing member to the surface of the image carrier during non-image formation, comprising: The operation modes of the metal soap supply operation include a first mode and a second mode, and the potential difference that causes the electrostatic force in the direction from the supply member to the developing member, which is formed between the supply member and the developing member, to act on the metal soap is smaller when the metal soap supply operation in the second mode is executed than when the metal soap supply operation in the first mode is executed. An image forming apparatus characterized by this.

2. The polarity of the potential difference formed between the supply member and the developing member is opposite between when the metal soap supply operation in the first mode is executed and when the metal soap supply operation in the second mode is executed. The image forming apparatus according to claim 1.

3. The potential difference formed between the supply member and the developing member is the same between when the metal soap supply operation in the second mode is executed and when the image forming operation is executed. The image forming apparatus according to claim 1 or 2.

4. The ratio of the surface moving speed of the developing member to the surface moving speed of the image carrier is greater when the metal soap supply operation is executed than when the image forming operation is executed. The image forming apparatus according to claim 1 or 2.

5. The back contrast, which is the difference between the surface potential of the image carrier in the developing unit and the developing voltage applied to the developing member, is greater when the metal soap supply operation is executed than when the image forming operation is executed. The image forming apparatus according to claim 1 or 2.

6. further comprising a transfer member facing the image carrier via an intermediate transfer body that can be brought into contact with and separated from the image carrier, During the execution of the metal soap supply operation, the intermediate transfer body is separated from the image carrier. The image forming apparatus according to claim 1 or 2.

7. further comprising a transfer member facing the image carrier via an intermediate transfer body that can be brought into contact with and separated from the image carrier, The potential difference that causes an electrostatic force in the direction from the image carrier to the transfer member, which is formed between the image carrier and the transfer member, to act on the metallic soap, is smaller during the execution of the metallic soap supply operation than during the execution of the image formation operation, in the image forming apparatus according to claim 1 or 2.

8. The applied voltage of the transfer member is 0 V during the execution of the metallic soap supply operation, in the image forming apparatus according to claim 7.

9. A charging member that charges the surface of the image carrier, An exposure unit that exposes the surface of the image carrier upstream of the charging unit by the charging member, further comprising, The exposure amount of the exposure unit is smaller during the execution of the metallic soap supply operation than during the execution of the image formation operation, in the image forming apparatus according to claim 1 or 2.

10. During the execution of the metallic soap supply operation, exposure by the exposure unit is not performed, in the image forming apparatus according to claim 9.

11. A rotatable image carrier, A developing member that supplies toner to the surface of the image carrier in a developing unit facing the image carrier to form a toner image, A supply member that supplies the toner to the developing member, A control unit that executes an image forming operation for forming the toner image on a recording material, and a metallic soap supply operation for applying a metallic soap having a polarity opposite to that of the toner contained in the toner to the surface of the image carrier by supplying the toner from the developing member to the surface of the image carrier during non-image formation, having, The operation modes of the metallic soap supply operation include a first mode and a second mode, and the amount of the metallic soap supplied from the developing member to the surface of the image carrier is less during the execution of the metallic soap supply operation in the second mode than during the execution of the metallic soap supply operation in the first mode, in the image forming apparatus characterized by this.

12. The potential difference that causes an electrostatic force in the direction from the supply member to the developing member, which is formed between the supply member and the developing member, to act on the metallic soap, is smaller during the execution of the metallic soap supply operation in the second mode than during the execution of the metallic soap supply operation in the first mode, in the image forming apparatus according to claim 11.

13. The polarity of the potential difference formed between the supply member and the developing member is opposite between the execution of the metallic soap supply operation in the first mode and the execution of the metallic soap supply operation in the second mode, in the image forming apparatus according to claim 11 or 12.

14. The ratio of the surface moving speed of the developing member to the surface moving speed of the image carrier is smaller when the metal soap supply operation in the second mode is executed than when the metal soap supply operation in the first mode is executed. The image forming apparatus according to claim 11 or 12.

15. The back contrast, which is the difference between the surface potential of the image carrier in the developing unit and the developing voltage applied to the developing member, is smaller when the metal soap supply operation in the second mode is executed than when the metal soap supply operation in the first mode is executed. The image forming apparatus according to claim 11 or 12.

16. The image forming apparatus further includes a transfer member facing the image carrier via an intermediate transfer body that can contact and separate from the image carrier. When the metal soap supply operation in the first mode is executed, the intermediate transfer body contacts the image carrier, and when the metal soap supply operation in the second mode is executed, the intermediate transfer body separates from the image carrier. The image forming apparatus according to claim 11 or 12.

17. The image forming apparatus further includes a transfer member facing the image carrier via an intermediate transfer body that can contact and separate from the image carrier. The potential difference that causes the electrostatic force in the direction from the image carrier to the transfer member, which is formed between the image carrier and the transfer member, to act on the metal soap is larger when the metal soap supply operation in the second mode is executed than when the metal soap supply operation in the first mode is executed. The image forming apparatus according to claim 11 or 12.

18. A charging member that charges the surface of the image carrier, An exposure unit that exposes the surface of the image carrier upstream of the charging unit by the charging member, The image forming apparatus further includes: The exposure amount of the exposure unit is larger when the metal soap supply operation in the second mode is executed than when the metal soap supply operation in the first mode is executed. The image forming apparatus according to claim 11 or 12.

19. When the metal soap supply operation in the first mode is executed, exposure by the exposure unit is not performed. The image forming apparatus according to claim 18.

20. The image forming apparatus further includes a torque detection unit that detects the driving torque of the image carrier. The control unit executes the metal soap supply operation when the number of rotations of the image carrier since the previous execution of the metal soap supply operation is equal to or greater than a first threshold value, or when the torque value detected by the torque detection unit is equal to or greater than a second threshold value. The image forming apparatus according to any one of claims 1, 2, 11, or 12.

21. The control unit when the total number of rotations of the image carrier is less than a third threshold value, executes the metal soap supply operation in a first mode; when the total number of rotations of the image carrier is equal to or greater than the third threshold value, executes the metal soap supply operation in a second mode. The image forming apparatus according to any one of claims 1, 2, 11, or 12.

22. The ratio of the surface moving speed of the developing member to the surface moving speed of the image carrier is a value between 85% and 115% when the metal soap supply operation is being executed. The image forming apparatus according to any one of claims 1, 2, 11, or 12.

23. A rotatable image carrier; a developing member that supplies toner to the surface of the image carrier in a developing unit facing the image carrier to form a toner image, and an initial operation for shifting the image carrier in a new state to a printable state, and an image forming operation for forming the toner image on a recording material, and a control unit that executes the above, having, a first peripheral speed ratio, which is the ratio of the surface moving speed of the developing member to the surface moving speed of the image carrier during at least a part of the period when the initial operation is being executed, is greater than a second peripheral speed ratio, which is the ratio of the surface moving speed of the developing member to the surface moving speed of the image carrier during the execution of the image forming operation. The image forming apparatus is characterized by this.

24. The image forming apparatus according to claim 23, wherein the first peripheral speed ratio is greater than 100%.

25. The image forming apparatus according to claim 23 or 24, wherein the first peripheral speed ratio is greater than 100% and the second peripheral speed ratio is 100% or less.

26. During the execution of the initial operation, a potential difference that causes an electrostatic force in the direction from the supply member to the developing member to act on the toner is formed between the supply member that supplies the toner to the developing member and the developing member. The image forming apparatus according to claim 23 or 24.

27. further includes a transfer member facing the image carrier via an intermediate transfer body that can come into contact with and separate from the image carrier, During the execution of the initial operation, the intermediate transfer body is separated from the image carrier. The image forming apparatus according to claim 23 or 24.

28. a charging member that charges the surface of the image carrier; an exposure unit that exposes the surface of the image carrier upstream of the charging unit by the charging member, and The exposure amount of the exposure unit is smaller during the execution of the initial operation than during the execution of the image forming operation. The image forming apparatus according to claim 23 or 24.

29. The image forming apparatus according to claim 28, wherein exposure by the exposure unit is not performed during execution of the initial operation.

30. Further comprising a torque detection unit that detects the drive torque of the image carrier, wherein the control unit makes the first circumferential speed ratio larger than the second circumferential speed ratio when the torque value detected by the torque detection unit during execution of the initial operation is equal to or greater than a fourth threshold value. The image forming apparatus according to claim 23 or 24.

31. Further comprising a contact member that contacts the surface of the developing member, wherein the contact member contains a fluorine-based low-friction substance. The image forming apparatus according to claim 23 or 24.

32. The image forming apparatus according to claim 31, wherein the contact member contacts an end portion of the developing member in the longitudinal direction and is a seal member that suppresses leakage of toner from the developing member to the outside.

33. The image forming apparatus according to claim 31, wherein the contact member has a sheet-like member provided to contact the developing member along the longitudinal direction, and is a seal member that suppresses leakage of toner from the developing member to the outside.

34. The toner contains a metal soap having a polarity opposite to that of the toner. The image forming apparatus according to claim 23 or 24.

35. The control unit performs an initial supply operation of supplying the metal soap contained in the toner from the developing member to the surface of the image carrier during at least a part of the period of execution of the initial operation. The image forming apparatus according to claim 34. The image forming apparatus according to claim 34, wherein the control unit performs an initial supply operation of supplying the metal soap contained in the toner from the developing member to the surface of the image carrier during at least a part of the period of execution of the initial operation.

36. Having a supply member that supplies the toner to the developing member, wherein a potential difference that causes an electrostatic force in a direction from the supply member to the developing member, which is formed between the supply member and the developing member, to act on the metal soap is greater during execution of the initial supply operation than during execution of the image forming operation. The image forming apparatus according to claim 35.

37. Further comprising a transfer member that faces the image carrier via an intermediate transfer member that can contact and separate from the image carrier, wherein a potential difference that causes an electrostatic force in a direction from the image carrier to the transfer member, which is formed between the image carrier and the transfer member, to act on the metal soap is smaller during execution of the initial operation than during execution of the image forming operation. The image forming apparatus according to claim 34.

38. The image forming apparatus according to claim 37, wherein the applied voltage of the transfer member is 0 V during execution of the initial operation.

39. The image forming apparatus according to any one of claims 1, 2, 11 or 12, wherein the developing member contacts the image carrier in the developing unit when the metal soap supply operation is executed.

40. The image forming apparatus according to claim 23 or 24, wherein the developing member contacts the image carrier in the developing unit when the initial operation is executed.

41. The image forming apparatus according to any one of claims 1, 2, 11, 12, wherein the metal species of the metal soap is at least one of zinc, calcium, and magnesium.

42. The image forming apparatus according to any one of claims 1, 2, 11, 12, wherein the metal soap is at least one of zinc stearate, calcium stearate, and magnesium stearate.

43. The image forming apparatus according to any one of claims 1, 2, 11, 12, wherein the metal soap has a particle size of 0.15 μm or more and 2.0 μm or less.

44. The image forming apparatus according to any one of claims 1, 2, 11, 12, 23 and 24, wherein the image carrier has a protective layer made of an acrylic resin on its outermost layer.

Images