Developing device, developer container, image forming apparatus, and surface treatment method for housing of developing device

Abstract

To prevent scattering of developer during replacement of a developer container.SOLUTION: A developing device 20 has: a housing 21 that has a wall part (receiving part) 24 formed with a receiving port 23 for receiving developer, and stores the developer; and a developing roller (developer carrier) 13 that is arranged inside the housing 21 and carries the developer. When the surface free energy of a surface of the wall part 24 formed with resin is represented by the total of a dispersion component γSd, a dipole component γSp, and a hydrogen bond component γSh, the dipole component γSp is 13.4 mN / m or more and 18.1 mN / m or less.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a developing device, a developer container, an image forming apparatus, and a surface treatment method for a housing of the developing device. [Background technology]

[0002] An image forming apparatus using an electrophotographic method includes a developing device having an image carrier and a developer container detachably attached to the developing device. The developing device has a receiving port for receiving the developer supplied from the supply port of the developer container.

[0003] For example, Patent Document 1 proposes providing a seal member that closes the gap between a developer container and a developing device in order to prevent leakage of developer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-243446 A (see Abstract) Summary of the Invention [Problem to be solved by the invention]

[0005] However, developer may accumulate on the inner surface of the receiving port of the developing device or the supply port of the developer container. If such developer accumulation occurs, there is a possibility that the developer may scatter around when the developer container is replaced.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has an object to suppress scattering of developer when replacing a developer container. [Means for solving the problem]

[0007] The developing device disclosed in the present disclosure has a receiving section with a receiving port formed therein for receiving the developer, a housing for accommodating the developer, and a developer carrier disposed in the housing for carrying the developer. The surface free energy of the surface of the receiving section made of resin is expressed as a dispersion component γ S d and the dipole component γ S p and hydrogen bond component γ S h When expressed as the sum of S p is greater than or equal to 13.4 [mN / m] and less than or equal to 18.1 [mN / m].

[0008] The developer container of the present disclosure has a supply section formed with a supply port for supplying the developer, and has a housing for accommodating the developer and an opening / closing member for opening and closing the supply port. S d and the dipole component γ S p and hydrogen bond component γ S h When expressed as the sum of S p is greater than or equal to 13.4 [mN / m] and less than or equal to 18.1 [mN / m].

[0009] In the surface treatment method for the housing of the developing device disclosed herein, in a developing device that receives a developer from an inlet formed in a receiving portion and stores the developer in the housing, by irradiating ultraviolet light onto at least a part of the surface of the housing formed of a resin, the surface free energy of the surface is reduced by a dispersion component γ S d and the dipole component γ S p and hydrogen bond component γ S h When expressed as the sum of S p should be greater than or equal to 13.4 [mN / m] and less than or equal to 18.1 [mN / m]. Effect of the Invention

[0010] In this disclosure, the dipole component γ of the surface free energy of the receiving portion of the housing of the developing device (or the supply portion of the housing of the developer container) S p Since the developer pressure is 13.4 to 18.1 [mN / m], the accumulation of developer on the inner surface of the receiving port (or supply port) is suppressed, and therefore scattering of developer when replacing the developer container can be suppressed. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram showing an overall configuration of an image forming apparatus according to a first embodiment; [Diagram 2] FIG. 2 is a cross-sectional view showing an image forming unit according to the first embodiment. [Diagram 3] FIG. 2 is a perspective view showing a developing device and a toner cartridge according to the first embodiment. [Figure 4] 2 is a cross-sectional view showing a mounting portion of a toner cartridge in the developing device according to the first embodiment. FIG. [Diagram 5] FIG. 2 is a block diagram showing a control system of the image forming apparatus according to the first embodiment. [Figure 6] 5A to 5C are schematic diagrams illustrating the operation of removing the toner cartridge from the image forming apparatus according to the first embodiment. [Figure 7] 2 is an enlarged view of the periphery of a toner storage unit of the developing device according to the first embodiment. FIG. [Figure 8] 3A to 3E are schematic diagrams illustrating a method for measuring a toner residual rate in the first embodiment. [Figure 9] 1 is a table showing contact angles and surface free energies in Experimental Examples 1 to 10. [Figure 10] 1 is a table showing the surface free energy, the toner remaining rate, and the condensation duration in Experimental Examples 1 to 10. [Figure 11] 1 is a graph showing the relationship between the dipole component and hydrogen bond component of the surface free energy and the overall evaluation result. [Figure 12] 2 is an enlarged cross-sectional view showing a part of the toner cartridge according to the first embodiment. FIG. [Figure 13]FIG. 11 is a cross-sectional view showing an image forming unit according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Embodiment 1 <Configuration of Image Forming Apparatus 1> First, a description will be given of the overall configuration of an image forming apparatus 1 according to the first embodiment. Fig. 1 is a diagram showing the overall configuration of the image forming apparatus 1. The image forming apparatus 1 shown in Fig. 1 forms an image using an electrophotographic process, and is, for example, an electrophotographic printer.

[0013] The image forming apparatus 1 comprises a medium supply section 60 that supplies a recording medium M such as printing paper, an image forming unit 10 that forms an image, a fixing device 70 that fixes the image on the recording medium M, a medium discharge section 80 that discharges the recording medium M, and a housing 1A that accommodates these.

[0014] The medium supply unit 60 includes a medium cassette 61 , a pickup roller 62 , a feed roller 63 , a retard roller 64 , a registration roller 65 , and a transport roller 66 .

[0015] The medium cassette 61 accommodates recording media M, such as printing paper, in a stacked state. The pickup roller 62 pulls out the recording media M one by one from the medium cassette 61. The feed roller 63 and the retard roller 64 separate the pulled-out recording media M one by one and send them to the transport path P1.

[0016] The registration rollers 65 correct the skew of the recording medium M sent to the conveying path P1 and convey the recording medium M further. The conveying rollers 66 convey the recording medium M conveyed from the registration rollers 65 to the image forming unit 10 along the conveying path P2.

[0017] The image forming unit 10 has a developing device 20 and a toner cartridge 30 as a developer container. The developing device 20 has a photoconductor drum 11 as an image carrier, a charging roller 12 as a charging member, a developing roller 13 as a developer carrier, a supply roller 14 as a supply member, a developing blade 15 as a layer regulating member, and a cleaning member 16. The configurations of the developing device 20 and the toner cartridge 30 will be described later.

[0018] A print head 18 serving as an exposure device is disposed opposite the photoconductor drum 11. The print head 18 has an LED array in which LEDs (light emitting diodes) serving as light emitting elements are arranged in one direction, and a lens array in which lens elements are arranged in the same direction, and forms an electrostatic latent image by irradiating the surface of the photoconductor drum 11 with light. The print head 18 is suspended and supported by a top cover 1B that covers the upper part of the housing 1A.

[0019] A transfer roller 19 serving as a transfer unit is disposed so as to come into contact with the surface of the photosensitive drum 11. The transfer roller 19 has a metal shaft and a semiconductive elastic layer formed on the surface of the shaft. A transfer voltage is applied to the transfer roller 19, and the toner image on the surface of the photosensitive drum 11 is transferred to the recording medium M passing between the photosensitive drum 11 and the transfer roller 19.

[0020] The fixing device 70 is disposed downstream of the image forming unit 10 in the transport direction of the recording medium M. The recording medium M that has passed between the photosensitive drum 11 and the transfer roller 19 is transported to the fixing device 70 by the rotation of the photosensitive drum 11.

[0021] The fixing device 70 has a fixing roller 71 and a pressure roller 72. The fixing roller 71 has a built-in heater such as a halogen lamp, and the pressure roller 72 is pressed against the fixing roller 71. The fixing roller 71 and the pressure roller 72 apply heat and pressure to the recording medium M passing between them, thereby fixing the toner image to the recording medium M.

[0022] The medium discharge section 80 has discharge rollers 81, 82, and 83 that transport the recording medium M that has passed through the fixing device 70 along the transport path P3 and discharge the recording medium M from a discharge opening 84. A stacker section 85 on which the recording medium M discharged from the discharge opening 84 is placed is formed in the top cover 1B.

[0023] In Fig. 1, the axial direction of the photosensitive drum 11 is the X direction (main scanning direction). The X direction is the axial direction of each roller in the image forming apparatus 1, and is also the arrangement direction of the light emitting elements of the print head 18. The movement direction of the recording medium M when the recording medium M passes through the image forming unit 10 is the Y direction. The direction perpendicular to the X direction and the Y direction is the Z direction. Here, the Z direction is the up-down direction.

[0024] The image forming apparatus 1 is configured to form a monochrome image by the image forming unit 10, but is not limited to such a configuration. For example, it may be configured to form a color image by arranging a plurality of image forming units for yellow, magenta, cyan, black, etc. in the conveying direction of the recording medium M.

[0025] 2 is a cross-sectional view showing the internal configuration of the image forming unit 10. The developing device 20 of the image forming unit 10 has a developing roller 13 as a developer carrier and a housing 21 (first housing) that houses it. The developing device 20 also has a photoconductor drum 11 as an image carrier, a charging roller 12 as a charging member, a supply roller 14 as a supply member, a developing blade 15 as a layer regulating member, and a cleaning member 16.

[0026] The photoconductor drum 11 is a cylindrical member having a photosensitive layer on the surface of a conductive support. The photosensitive layer is a laminate of a charge generating layer and a charge transport layer. The photoconductor drum 11 rotates in the direction indicated by the arrow.

[0027] The charging roller 12 is disposed so as to be in contact with the surface of the photoreceptor drum 11, and rotates following the rotation of the photoreceptor drum 11. The charging roller 12 has a metal shaft (core metal), an elastic layer formed on the surface of the shaft, and a surface layer formed on the surface of the elastic layer. A charging voltage is applied to the charging roller 12, which uniformly charges the surface of the photoreceptor drum 11.

[0028] The developing roller 13 is disposed so as to contact the surface of the photoreceptor drum 11, and rotates in the opposite direction to the photoreceptor drum 11 (the direction in which the surface moves in the forward direction at the contact portion). The developing roller 13 has a metal shaft (core metal) and an elastic layer formed on the surface of the shaft. The elastic layer is made of an elastic body such as silicone rubber or urethane. The developing roller 13 develops the electrostatic latent image on the surface of the photoreceptor drum 11 with toner as a developer.

[0029] Supply roller 14 is disposed so as to contact the surface of developing roller 13, and rotates in the same direction as developing roller 13 (a direction in which the surface moves in the opposite direction at the contact portion). Supply roller 14 has a metal shaft (core metal) and an elastic layer formed on the surface of the shaft. The elastic layer is formed of a foamed elastic body such as silicone rubber. Supply roller 14 supplies toner as a developer to developing roller 13.

[0030] The developing blade 15 is a blade formed by bending a metal plate member, and the bent portion is pressed against the surface of the developing roller 13. The developing blade 15 regulates the thickness of the toner layer (developer layer) on the surface of the developing roller 13.

[0031] The cleaning member 16 is, for example, a resin blade or roller arranged so as to come into contact with the surface of the photoconductor drum 11. The cleaning member 16 removes toner remaining on the surface of the photoconductor drum 11 after the transfer of a toner image, which will be described later.

[0032] A waste toner transport unit 17 is provided below the cleaning member 16 to transport the toner removed from the surface of the photoconductor drum 11 to the outside of the developing device 20. The toner transported by the waste toner transport unit 17 is transported to a waste toner storage unit (not shown).

[0033] The developing device 20 has a toner storage section 26 as a developer storage section inside its housing 21. In the toner storage section 26, the above-mentioned developing roller 13, supply roller 14, and developing blade 15 are arranged.

[0034] A toner remaining amount detection bar 27 is also disposed within toner storage unit 26. By the rotation transmitted from a motor (not shown), toner remaining amount detection bar 27 rotates along a rotation trajectory shown by a dashed line in Fig. 2. The rotational resistance received by toner remaining amount detection bar 27 changes depending on the amount of toner remaining in toner storage unit 26, and the rotation period changes accordingly.

[0035] Stirring bars 28a and 28b are provided in the toner storage unit 26 to stir the toner in the toner storage unit 26. The toner in the toner storage unit 26 is stirred by the rotation of the stirring bars 28a and 28b, and is supplied to the developing roller 13 by the supply roller 14.

[0036] A cartridge mounting section 22 into which the toner cartridge 30 is mounted is formed in the upper portion of the housing 21. A receiving port 23, which is an opening for receiving the toner supplied from the toner cartridge 30, is formed in a wall portion (receiving portion) 24 of the cartridge mounting section 22.

[0037] The toner cartridge 30 has a housing 31, and inside the housing 31, a toner storage chamber 35 is formed as a developer storage section in which toner is stored. A supply port 33, which is an opening for discharging the toner in the toner storage chamber 35, is formed in a bottom portion 32 (supply portion) of the housing 31. When the toner cartridge 30 is mounted in the cartridge mounting portion 22, the bottom portion 32 of the toner cartridge 30 faces the wall portion 24 of the developing device 20, and the supply port 33 of the toner cartridge 30 faces the receiving port 23 of the developing device 20.

[0038] The toner storage chamber 35 is provided with a shutter 34 as an opening / closing member that opens and closes the supply port 33. The shutter 34 has a substantially semi-cylindrical shape with its axial direction in the X direction, and is provided rotatable about its central axis in the X direction.

[0039] A part of the shutter 34 protrudes from the housing 31 in the axial direction (X direction) and is connected to an operation lever (not shown). The shutter 34 rotates by the operation of the operation lever by a user, and opens and closes the supply port 33.

[0040] When the shutter 34 is in a position to open the supply port 33, the toner storage chamber 35 of the toner cartridge 30 communicates with the toner storage section 26 of the developing device 20. That is, the toner in the toner storage chamber 35 is supplied to the toner storage section 26 through the supply port 33 and the receiving port 23.

[0041] Stirring bars 38a and 38b for stirring the toner are also disposed in the toner storage chamber 35. Stirring bar 38a is disposed inside the shutter 34, and stirring bar 38b is disposed adjacent to the shutter 34. Both stirring bars 38a and 38b are rotatable about a central axis in the X direction. The rotation of stirring bars 38a and 38b stirs the toner in the toner storage chamber 35 and transports it to the supply port 33.

[0042] In addition, a waste toner storage chamber 36 for storing waste toner discharged from the developing device 20 is provided adjacent to the toner storage chamber 35 inside the housing 31 of the toner cartridge 30. This waste toner storage chamber 36 is not necessarily provided.

[0043] 3 is a diagram showing a state in which the developing device 20 and the toner cartridge 30 are separated from each other. The toner cartridge 30 is guided in the attachment / detachment direction indicated by the arrow D by a guide rail (not shown) provided on the developing device 20. The toner cartridge 30 is removed from the cartridge mounting portion 22 of the developing device 20 with the shutter 34 closing the supply port 33.

[0044] 4 is a cross-sectional view showing the vicinity of the receiving opening 23 of the developing device 20 and the supply opening 33 of the toner cartridge 30. When the toner cartridge 30 is mounted in the cartridge mounting portion 22 of the developing device 20, the supply opening 33 of the toner cartridge 30 and the receiving opening 23 of the developing device 20 are positioned so as to overlap each other.

[0045] The housing 21, which is the outer shell of the developing device 20, is made of resin (e.g., engineering plastic). More specifically, the housing 21 is made of "Zylon (registered trademark) X352V" manufactured by Asahi Chemical Industry Co., Ltd., which is a polymer alloy of polyphenylene ether (PPE) and polystyrene (PS). This polymer alloy has a low specific gravity, low water absorption, and is flame retardant, and is therefore advantageous in terms of the weight reduction, dimensional stability, and reliability of the developing device 20.

[0046] The wall portion (receiving portion) 24 of the housing 21 forms the bottom surface of the cartridge mounting portion 22 of the developing device 20. The above-mentioned receiving opening 23 is formed in the wall portion 24. A seal member 25 is disposed on the wall portion 24 so as to surround the receiving opening 23. The seal member 25 is formed of, for example, a sponge.

[0047] The seal member 25 is sandwiched and compressed between the wall portion 24 of the developing device 20 and the bottom portion 32 of the toner cartridge 30. This seal member 25 prevents toner leakage from the receiving opening 23 and the supply opening 33.

[0048] The housing 31 of the toner cartridge 30 is made of resin (e.g., engineering plastic) like the housing 21 of the developing device 20. More specifically, the housing 31 is made of "Zylon (registered trademark) X352V" manufactured by Asahi Chemical Industry Co., Ltd., which is a polymer alloy of PPE and PS.

[0049] The material of the housing 21 of the developing device 20 and the housing 31 of the toner cartridge 30 is not limited to a polymer alloy of PPE and PS (e.g., Zylon (registered trademark) X352V) but may be, for example, ABS (acrylonitrile-butadiene-styrene copolymer).

[0050] <Toner> Next, the toner used in the image forming unit 10 will be described. The toner is a non-magnetic, single-component, negatively charged toner. The average particle size of the toner is about 7.5 μm, and the circularity is about 0.94. The average particle size is measured using a Multisizer III manufactured by Coulter Corporation. The circularity is measured using a Flow Particle Image Analyzer FPIA-3000 manufactured by Sysmex Corporation.

[0051] The toner is obtained by adding an external additive (external additive) such as inorganic fine powder or organic fine powder to toner base particles containing at least a binder resin.

[0052] The binder resin is preferably a polyester resin, a styrene-acrylic resin, an epoxy resin, or a styrene-butadiene resin. A plurality of types of binder resins may be mixed. In this embodiment, a mixture of two or more types of amorphous polyester resins and a crystalline polyester resin having a crystal structure is used.

[0053] A release agent and a colorant are added to the binder resin, and in addition, additives such as a charge control agent, a conductivity adjuster, a flowability improver, or a cleaning property improver may be added.

[0054] The release agent is not particularly limited, but may be low molecular weight polyethylene, low molecular weight polypropylene, copolymers of olefins, aliphatic hydrocarbon waxes such as microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, or block copolymers thereof, waxes mainly composed of fatty acid esters such as carnauba wax and Montan acid ester wax, and fatty acid esters such as deoxidized carnauba wax that have been partially or completely deoxidized. The content of the release agent is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 12 parts by weight, relative to 100 parts by weight of the binder resin. A plurality of waxes may be used in combination.

[0055] The colorant is not particularly limited, but dyes, pigments, etc. generally used as yellow, magenta, cyan, and black toner colorants can be used alone or in combination. Specifically, for example, carbon black, iron oxide, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, pigment blue 15:3, solvent blue 35, quinacridone, carmine 6B, disazo yellow, etc. can be used. The content of the colorant is preferably 2 to 25 [parts by weight], more preferably 2 to 15 [parts by weight], relative to 100 [parts by weight] of the binder resin.

[0056] The charge control agent may be a known one. For example, in the case of a negatively charged toner, there are azo complex charge control agents, salicylic acid complex charge control agents, calixarene charge control agents, etc. The content of the charge control agent is preferably 0.05 to 15 parts by weight, more preferably 0.1 to 10 parts by weight, relative to 100 parts by weight of the binder resin.

[0057] The external additive is added to improve environmental stability, charge stability, developability, fluidity, and storage stability, and known additives can be used. The content of the external additive is 0.01 to 10 parts by weight, preferably 0.05 to 8 parts by weight, per 100 parts by weight of the binder resin. In this embodiment, several types of silica (positive and negative charge polarities) with an average particle size of 14 μm, colloidal silica (negative charge) with an average particle size of 110 μm, and melamine (positive charge) with an average particle size of 200 μm are added to 100 parts by weight of the base particles, and the total amount is within the above range.

[0058] The toner uses silica (SiO2) as an external additive. The amount of external additive can be evaluated by measuring the content (detected amount) [weight %] of Si (silicon) in the toner by elemental analysis using energy dispersive X-ray spectrometry (EDX). For elemental analysis, an energy dispersive X-ray fluorescence analyzer "EDX-800HS" manufactured by Shimadzu Corporation is used. The measurement environment is a helium (He) gas atmosphere, and the X-ray tube voltage is 15 [kV], 50 [kV]. The detected amount of Si in the toner of this embodiment is 0.98 to 1.28 [weight %].

[0059] Generally, when a sample is irradiated with X-rays, fluorescent X-rays, which are X-rays specific to the atoms contained in the sample, are generated and emitted from the sample. Since fluorescent X-rays have wavelengths (energy) specific to each element, qualitative analysis can be performed by examining the wavelengths of the fluorescent X-rays. In addition, the intensity of fluorescent X-rays is a function of concentration. Therefore, quantitative analysis can be performed by measuring the amount of X-rays for each element-specific wavelength.

[0060] In this embodiment, the toner is irradiated with X-rays emitted from an X-ray tube of an energy dispersive X-ray fluorescence analyzer, and the Si content (detection amount) is measured based on the fluorescent X-rays emitted from Si atoms contained in the external additives of the toner. In the energy dispersive X-ray fluorescence analyzer, the atmosphere in the sample chamber is replaced with helium (He) gas, and X-rays are irradiated at a voltage of 15 kV and a current of 100 μA.

[0061] In general, the less the external additive in the toner, the more exposed the toner base particles are, and therefore the more susceptible the toner base particles are to the external environment. When silica is mainly used as an external additive in the toner, the hydrophobic silica is covered by the toner base particles, thereby reducing the effects of the external environment. When the detected amount of Si in the silica used as the external additive is 1.28 [wt %] or less, the toner base particles are more exposed, and therefore more susceptible to the external environment, and the toner is more likely to adhere to the receiving port 23 or the supply port 33, but by applying this embodiment, such toner adhesion can be reduced.

[0062] The toner charge (blow-off charge) was measured by stirring the toner and carrier by shaking. Here, Powdertech Co., Ltd.'s ferrite carrier "EF96-35" was used as the carrier, and 0.5 [g] of toner and 9.5 [g] of carrier were mixed. The toner and carrier mixture (150 [mg]) was placed in a container and shaken using Yayoi Co., Ltd.'s shaker "YS-LD". The shaking frequency was 200 [times / min], and the shaking time was 300 [seconds].

[0063] After shaking, the powder charge measuring device "TB-203" manufactured by Kyocera Chemical Corporation was used to perform suction for 10 seconds with a blow pressure of 7.0 kPa and a suction pressure of -4.5 kPa, and the charge amount and suction amount were output every 0.1 seconds to a PC (personal computer). The charge amount per unit weight of the toner particles Q / M calculated from the average charge amount and suction amount output during the last 2 seconds of the suction time (10 seconds) was approximately -35 μC / g. The measurements were performed at a temperature of 25°C and a relative humidity of 50%.

[0064] <Image forming device control system> Next, a description will be given of a control system of the image forming apparatus 1. Fig. 5 is a block diagram showing the control system of the image forming apparatus 1. The image forming apparatus 1 has a control unit 100, a receiving memory 91, an image data editing memory 92, an operation unit 93, a sensor group 94, and a power supply circuit 110.

[0065] The control unit 100 includes a print control unit (main control unit) 101, an I / F (interface) control unit 102, a head control unit 103, a fixing control unit 104, a fixing drive control unit 105, a transport control unit 106, and a drive control unit 107.

[0066] The print control unit 101 includes a microprocessor, a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output port, a timer, etc. The print control unit 101 controls the overall operation of the image forming apparatus 1 by executing a predetermined program.

[0067] Specifically, the print control unit 101 receives print data and control commands from an external device via the I / F control unit 102, and performs overall control of the head control unit 103, the fixing control unit 104, the fixing drive control unit 105, the conveying control unit 106, the drive control unit 107, and the power supply circuit 110 to perform printing operations.

[0068] The I / F control unit 102 receives print data and control commands from an external device such as a personal computer, and also transmits information regarding the state of the image forming apparatus 1 to the external device.

[0069] The receiving memory 91 temporarily stores print data input from an external device via the I / F control unit 102 .

[0070] The image data editing memory 92 receives the print data stored in the receiving memory 91, and records image data obtained by editing the print data.

[0071] The operation unit 93 has a display unit that displays information related to the state of the image forming apparatus 1, and an input unit that accepts operation inputs from the user. The display unit is formed of, for example, an LED lamp, and the input unit is formed of, for example, a button or a touch panel.

[0072] The sensor group 94 has various sensors that monitor the operating state of the image forming apparatus 1. Specifically, these include a position detection sensor that detects the position of the medium P on the transport path, a temperature and humidity sensor, a print density sensor, and a toner remaining amount sensor.

[0073] The power supply circuit 110 includes a charging roller power supply 111 that applies a charging voltage to the charging roller 12, a developing roller power supply 112 that applies a developing voltage to the developing roller 13, a supply roller power supply 113 that applies a supply voltage to the supply roller 14, a developing blade power supply 114 that applies a blade voltage to the developing blade 15, and a transfer roller power supply 115 that applies a transfer voltage to the transfer roller 19.

[0074] The head control unit 103 controls the emission of each LED of the print head 18 based on the image data recorded in the image data editing memory 92 .

[0075] The fixing control unit 104 has a temperature adjustment circuit, and supplies a current to a heater in the fixing roller 71 based on an output signal of a temperature sensor such as a thermistor provided in the fixing device 70 .

[0076] The fixing drive control unit 105 controls the rotation of the fixing motor 73 that rotates the fixing roller 71. Note that the discharge roller 81 of the medium discharge unit 80 is rotated by the rotation transmitted from the fixing motor 73.

[0077] The conveyance control unit 106 controls the rotation of a conveyance motor 108 that drives the pickup roller 62, the feed roller 63, the registration roller 65, and the conveyance roller 66. The rotation of the conveyance motor 108 is transmitted to the pickup roller 62, the registration roller 65, and the conveyance roller 66 via an electromagnetic clutch (not shown) or the like.

[0078] A drive control unit 107 controls the rotation of a drive motor 109 that rotates and drives the photosensitive drum 11. The rotation of the photosensitive drum 11 is also transmitted to the developing roller 13 and the supply roller 14 via a gear train (not shown).

[0079] <Printing operation> Next, a printing operation (image forming operation) by the image forming apparatus 1 of the first embodiment will be described. The print control unit 101 executes a printing operation when it receives a print job from a higher-level device such as a personal computer via the I / F control unit 102. The print job includes a print command and print data.

[0080] The print control unit 101 sends control signals to the fixing drive control unit 105, the transport control unit 106, and the drive control unit 107, and causes the fixing motor 73, the transport motor 108, and the drive motor 109 to rotate at predetermined timing and at predetermined speeds, respectively.

[0081] This rotates the pickup roller 62 and the feed roller 63, which feed the recording media M one by one from the media cassette 61 and transport them along the transport path P1. Also, the registration rollers 65 and the transport rollers 66 rotate at predetermined timings to transport the recording media M toward the developing device 20.

[0082] In the developing device 20, the photoconductor drum 11 is rotated by a drive motor 109. In the fixing device 70, the fixing roller 71 is rotated by a fixing motor 73. In addition, the fixing control unit 104 controls the current flowing through the heater, and the fixing roller 71 is heated to a predetermined fixing temperature.

[0083] In addition, the print control unit 101 applies a charging voltage, a developing voltage and a supply voltage to the charging roller 12, the developing roller 13 and the supply roller 14 from the charging roller power supply 111, the developing roller power supply 112 and the supply roller power supply 113 of the power supply circuit 110.

[0084] The print control unit 101 processes the print data received from the host device and then transmits it to the head control unit 103. The head control unit 103 controls the light emission of the print head 18 based on the received print data, and exposes the surface of the photoconductor drum 11 to light.

[0085] In the developing device 20, the toner in the toner storage section 26 is adhered to the surface of the developing roller 13 by the supply roller 14. The thickness of the toner adhered to the surface of the developing roller 13 is regulated by the developing blade 15, and the toner becomes a thin layer of uniform thickness.

[0086] In the developing device 20, the charging roller 12 to which a charging voltage is applied uniformly charges the surface of the photoconductor drum 11. The charged surface of the photoconductor drum 11 is selectively exposed to light by the print head 18 in accordance with image data. As a result, an electrostatic latent image is formed on the surface of the photoconductor drum 11.

[0087] The electrostatic latent image formed on the surface of the photoconductor drum 11 is developed into a toner image by the adhesion of toner from the developing roller 13. The toner image on the surface of the photoconductor drum 11 is transferred to the recording medium M by a transfer voltage applied to the transfer roller 19 from the transfer roller power supply 115.

[0088] The toner remaining on the surface of the photoconductor drum 11 after transfer is removed by the cleaning member 16. The removed toner is transported to the outside of the developing device 20 by the waste toner transport unit and is stored in the waste toner storage unit.

[0089] Meanwhile, the recording medium M that has passed between the photoconductor drum 11 and the transfer roller 19 is transported to the fixing device 70 by the rotation of the photoconductor drum 11. In the fixing device 70, heat and pressure are applied to the toner image by a fixing roller 71 and a pressure roller 72, so that the toner image is fixed onto the recording medium M.

[0090] The recording medium M on which the toner image has been fixed is discharged from a discharge port 84 by discharge rollers 81, 82, and 83 which are rotated by the rotation transmitted from the fixing motor 73, and is stacked on a stacker unit 85.

[0091] In the above printing operation, the print control unit 101 determines the amount of toner remaining in the toner storage unit 26 based on the rotation period of the toner remaining amount detection bar 27 detected by the toner remaining amount sensor of the sensor group 94 (FIG. 5). A state in which the toner level in the toner storage unit 26 falls below the rotation range of the toner remaining amount detection bar 27 is determined to be a toner low state.

[0092] When the print control unit 101 determines that the toner is low, it displays a message on the display unit of the operation unit 93 urging the user to replace the toner cartridge 30. Furthermore, if a specified number of sheets are printed without replacing the toner cartridge 30, it determines that the toner is empty, and displays a message on the display unit of the operation unit 93 to the effect that there is no toner left in the developing device 20.

[0093] <Measures to prevent toner scattering when replacing toner cartridges> Next, a description will be given of measures against toner scattering when replacing the toner cartridge 30 according to embodiment 1. First, a description will be given of toner scattering when replacing the toner cartridge 30.

[0094] Fig. 6 is a schematic diagram showing the operation of removing the toner cartridge 30 from the developing device 20. When removing the toner cartridge 30 from the developing device 20, the user rotates the shutter 34 by operating the lever to close the supply port 33 of the toner cartridge 30. Next, as shown in Fig. 6, the top cover 1B of the image forming apparatus 1 is opened (arrow C), and the toner cartridge 30 is removed from the developing device 20 (arrow D).

[0095] 7 is a schematic diagram showing a state in which the toner level in the toner storage section 26 of the developing device 20 has become toner-low. During printing operation, toner is supplied from the supply port 33 of the toner cartridge 30 through the receiving port 23 of the developing device 20 to the toner storage section 26, but depending on the usage environment and conditions of the image forming apparatus 1, toner may adhere to the inner surface of the receiving port 23. When printing operation is repeated, toner accumulates on the inner surface of the receiving port 23, as shown by the reference symbol T1.

[0096] The toner thus accumulated in the receiving port 23 may adhere to the bottom 32 or the surface of the shutter 34 of the toner cartridge 30 and scatter to the surroundings when the toner cartridge 30 shown in Fig. 6 is removed. The toner scattered from the toner cartridge 30 to the surroundings may adhere to, for example, the conveying roller 66, and further to the recording medium M, causing stains.

[0097] Therefore, in the first embodiment, the surface of the wall 24 (the portion where the receiving port 23 is formed) of the housing 21 of the developing device 20 is modified so as to suppress the accumulation of toner on the inner surface of the receiving port 23 of the developing device 20. First, the relationship between the surface characteristics of the housing 21 of the developing device 20 and the adhesion of toner will be described.

[0098] 8(A) to (E) are schematic diagrams showing a method for measuring the toner remaining rate on the surface of the housing 21. The test piece 50 shown in Fig. 8(A) is a flat plate-shaped member cut out from the wall portion 24 of the housing 21 of the developing device 20. As described above, the material of the housing 21 is a polymer alloy of PPE and PS (more specifically, "Zylon (registered trademark) X352V").

[0099] The test piece 50 is a rectangular flat plate having a length of 25 mm, a width of 20 mm, and a thickness of 1.5 mm.

[0100] First, a weight W1 [g] of the test piece 50 is measured. Then, a toner 52 formed into a cylindrical shape with a diameter of 6 [mm] and a height of 1 [mm] is placed on a surface 51 of the test piece 50.

[0101] Next, as shown in Fig. 8(B), a weight plate 53 is placed on the toner 52 on the test piece 50 for 10 seconds. The weight plate is made of polyethylene terephthalate (PET) and weighs 0.5 g. The toner 52 on the test piece 50 is crushed by the weight of the weight plate 53.

[0102] Next, as shown in FIG. 8C, the weight plate 53 is removed, and the total weight W2 [g] of the test piece 50 and the toner 54 crushed by the weight plate 53 is measured.

[0103] 8(D), the test piece 50 is tilted by 120° with respect to the horizontal plane and maintained in this state for 10 seconds. The more the surface 51 of the test piece 50 has surface characteristics that make it difficult for the toner 54 to adhere to it, the more the toner 54 falls off the test piece 50.

[0104] Next, as shown in FIG. 8(E), the test piece 50 is returned to a horizontal position, and the total weight W3 [g] of the test piece 50 and the toner 55 remaining on its surface 51 is measured.

[0105] Then, the toner remaining rate [%] on the surface 51 of the test piece 50 is calculated by the following formula (1). Toner remaining rate [%] = (W3-W1) / (W2-W1) … (1)

[0106] The lower the toner remaining rate, the less likely to have toner adhere to surface 51 (including those that have been surface-treated or have a film or the like attached) of test piece 50. In other words, by lowering the toner remaining rate through surface modification of housing 21 of developing device 20, it is possible to suppress toner accumulation on the inner surface of receiving port 23 and toner scattering when toner cartridge 30 is replaced.

[0107] Next, a description will be given of a method for calculating the surface free energy of the surface 51 of the test piece 50. The surface free energy is calculated using the following formula (2) according to the extended Fowkes theory.

[0108]

number

[0109] In formula (2), γ L is γ L d +γ L p +γ L h The surface free energy of the liquid is expressed as γ L d represents the dispersion component of the surface free energy of the liquid. γL p represents the dipole component of the surface free energy of the liquid. γ L h represents the hydrogen bonding component of the surface free energy of the liquid. γ S d represents the dispersion component of the surface free energy of a solid. γ S p represents the dipole component of the surface free energy of a solid. γ S h represents the hydrogen bonding component of the surface free energy of the solid, and θ represents the contact angle.

[0110] The dispersion component of surface free energy is the force that attracts molecules to each other, which occurs when the constant vibration of all molecules causes a momentary imbalance in charge. The dipole component is the force that polar molecules face each other with positive and negative charges facing each other due to a permanent dipole. The hydrogen bond component is the force that bonds hydrogen atoms to highly electronegative atoms of other molecules due to the strong polarity between hydrogen atoms and atoms with high electronegativity, such as F and H, O and H, and N and H.

[0111] In general, the sum of the dispersion force due to the dispersion component and the orientation force due to the dipole component is the van der Waals force, and the hydrogen bonding force due to the hydrogen bonding component is a force stronger than the van der Waals force.

[0112] Three types of liquids were used to measure the contact angle θ: n-dodecane, a saturated hydrocarbon liquid; water, a liquid with hydrogen bonds; and diiodomethane, another type of liquid. The components of the surface free energy of these three liquids are shown in Table 1 below.

[0113] [Table 1]

[0114] Using the contact angle θ between the three types of liquid and the surface 51 of the test piece 50, the surface free energy of the liquid shown in Table 1, and formula (2), the surface free energy γ of the surface 51 of the test piece 50 was calculated. Sd ,γ S p ,γ S h The contact angle θ was measured using a contact angle meter system CA-X manufactured by Kyowa Interface Science Co., Ltd.

[0115] Surface free energy of liquid γ L d ,γ L p ,γ L h From Table 1 and formula (2), the surface free energy γ of the test piece 50 S d ,γ S p ,γ S h The method for calculating is as follows.

[0116] First, the γ L d ,γ L p ,γ L h The value of (γ L h =0), equation (2) can be transformed into the following equation (3).

number

[0117] Both sides of equation (3) are 2(γ L d ) 1 / 2 Dividing by this gives us the following equation (4).

number

[0118] Here, Y and X are defined as shown in the following equations (5) and (6).

number

number

[0119] Using Y and X defined in equations (5) and (6), equation (4) can be expressed as the following equation (7).

number

[0120] The gamma values ​​shown in Table 1 L d ,γ L p ,γ L h The values ​​of Y and X are calculated by substituting the measured values ​​of the contact angle θ and the values ​​of θ into equations (5) and (6). The calculated values ​​of Y and X are then substituted into equation (7) to obtain (γ S p ) 1 / 2 and (γ S d ) 1 / 2 By solving the simultaneous equations, γ S p ,γ S d Calculate the value of

[0121] For example, when the measured values ​​of the contact angle θ (when diethyl ether and n-dodecane were used) of each test piece in Experimental Examples 1 to 6 described later are used, as shown in Table 2 below, S p ,γ S d The value of is calculated.

[0122] [Table 2]

[0123] And, γ S p ,γ S d By substituting the calculated value of and the measured contact angle θ (when using water) into equation (2), γ S h The value of is calculated.

[0124] For example, γ S p ,γ S d By substituting the calculated value of and the measured contact angle θ (when using water) of each test piece into equation (2), γ is obtained as shown in Table 3 below. S h The value of is calculated.

[0125] [Table 3]

[0126] <Experimental Examples 1-10> Next, experimental examples 1 to 10 in which the surface characteristics of the surface 51 of the test piece 50 are made different will be described.

[0127] Experimental example 1. The test piece 50 of Experimental Example 1 was prepared by cutting out a flat plate member from the wall 24 of the housing 21, which was a molded body of "Zylon (registered trademark) X352V", a polymer alloy of PPE and PS. No surface modification (surface treatment or application of tape or the like) was performed on the surface 51 of the test piece 505.

[0128] Experimental example 2. The test piece 50 of Experimental Example 2 was prepared by irradiating the surface of a flat plate member cut out from the housing 21 with ultraviolet (UV) light for 30 seconds, as in Experimental Example 1. For UV irradiation, an "UV cleaning surface modification device ASM2003N" manufactured by Asumi Giken Co., Ltd. was used, and UV with wavelengths of 185 nm and 254 nm was irradiated simultaneously. The distance from the UV lamp to the surface 51 of the test piece 50 was 100 mm, and the UV illuminance at that position was 24 mW / cm. 2 ].

[0129] Experimental example 3. The test piece 50 of Experimental Example 3 was prepared by irradiating UV light for 60 seconds on the surface of a flat plate member cut out from the housing 21 in the same manner as in Experimental Example 1. The UV irradiation conditions were the same as those of Experimental Example 2, except for the irradiation time.

[0130] Experimental example 4. The test piece 50 of Experimental Example 4 was prepared by irradiating the surface of a flat plate member cut out from the housing 21 with UV light for 180 seconds in the same manner as in Experimental Example 1. The UV irradiation conditions were the same as those in Experimental Example 2, except for the irradiation time.

[0131] Experimental Example 5. The test piece 50 of Experimental Example 5 was prepared by irradiating the surface of a flat plate member cut out from the housing 21 with UV light for 300 seconds in the same manner as in Experimental Example 1. The UV irradiation conditions were the same as those in Experimental Example 2, except for the irradiation time.

[0132] Experimental Example 6. The test piece 50 of Experimental Example 6 was prepared by irradiating the surface of a flat plate member cut out from the housing 21 with UV light for 600 seconds in the same manner as in Experimental Example 1. The UV irradiation conditions were the same as those in Experimental Example 2, except for the irradiation time.

[0133] Experimental Example 7. The test piece 50 of Experimental Example 7 was prepared by attaching a "wrapping film sheet 261X0.3 μm" manufactured by 3M Japan Ltd. (a polyester film coated with aluminum oxide abrasive grains to give a surface roughness of 0.3 μm) to the surface of a flat plate member cut out from the housing 21 in the same manner as in Experimental Example 1.

[0134] Experimental Example 8. Test piece 50 of experimental example 8 was prepared by adhering "Aluminum Foil Tape 425" (aluminum foil coated with an acrylic adhesive) manufactured by 3M Japan Ltd. to the surface of a flat plate member cut out from housing 21 in the same manner as in experimental example 1.

[0135] Experimental Example 9. The test piece 50 of Experimental Example 9 was prepared by adhering "Kapton (registered trademark) Adhesive Tape No. 653F" (a polyimide film coated with a flame-retardant acrylic adhesive) manufactured by Teraoka Manufacturing Co., Ltd. to the surface of a flat plate member cut out from the housing 21 in the same manner as in Experimental Example 1.

[0136] Experimental Example 10. Test piece 50 of experimental example 10 was prepared by adhering "Fluororesin Tape No. 8410" (a fluororesin film coated with a silicone-based adhesive) manufactured by Teraoka Seisakusho Co., Ltd. to the surface of a flat plate member cut out from housing 21 in the same manner as in experimental example 1.

[0137] For each of Experimental Examples 1 to 10, the contact angle with the liquids (dichloromethane, n-dodecane, water) shown in Table 1 was measured, and the surface free energy was calculated based on the measurement results. Figure 9 shows the contact angle measurement results and the values ​​of each component of the surface free energy for each of Experimental Examples 1 to 10.

[0138] Compared to Experimental Example 1, Experimental Examples 2 to 6 have smaller water contact angles. Furthermore, in Experimental Examples 2 to 6, the longer the UV irradiation time, the smaller the water contact angle. That is, by performing UV irradiation and by lengthening the UV irradiation time, the hydrophilicity of surface 51 of test piece 50 is increased. This is because active oxygen in the air formed by UV collides with surface 51 of test piece 50, cuts molecular chains in the surface layer, and reacts with the cut molecules to generate functional groups (OH, CHO, COOH, etc.) that are highly hydrophilic.

[0139] Since the toner contains hydrophobic silica as an external additive, the more hydrophilic the surface 51 of the test piece 50 becomes, the more difficult it becomes for the toner to adhere to the surface 51 of the test piece 50 .

[0140] Using the test pieces 50 of Experimental Examples 1 to 10, the toner remaining rate was measured by the method described with reference to FIGS. 8(A) to (E).

[0141] On the other hand, the more hydrophilic the surface 51 of the test piece 50 is, the less toner adheres to it, but the longer it takes to recover from the condensation state.

[0142] When the usage environment of the image forming apparatus 1 suddenly changes, there is a possibility that condensation will occur in the image forming unit 10. If condensation occurs on the housing 21 of the developing device 20 and the condensation state continues for a long time, the toner in contact with the housing 21 will absorb moisture, and this moisture absorption of the toner may adversely affect the print quality. Therefore, in addition to measuring the toner remaining rate, the duration of the condensation state was also measured.

[0143] The method for measuring the duration of the condensation state is as follows. First, the test piece 50 was left in an environment with a temperature of 10°C and a relative humidity of 20% for 24 hours. After that, the test piece 50 was moved to an environment with a temperature of 28°C and a relative humidity of 80% to cause condensation. The condensation can be visually confirmed as cloudiness on the surface 51 of the test piece 50.

[0144] Next, the test piece 50 was moved to an environment of a temperature of 28[°C] and a relative humidity of 80[%], and then the time until the clouding on the surface 51 of the test piece 50 caused by condensation disappeared was measured. Whether or not the clouding on the surface 51 of the test piece 50 disappeared was judged by visual observation.

[0145] FIG. 10 shows the measurement results of the toner remaining rate and the condensation duration for Experimental Examples 1 to 10, and the evaluation results based on the results.

[0146] Regarding the judgment of the toner remaining rate, when the toner remaining rate is less than 10%, the effect of reducing the toner adhesion is deemed sufficient and it is judged as "◯" (good). On the other hand, when the toner remaining rate is 10% or more, the effect of reducing the toner adhesion is deemed insufficient and it is judged as "×" (bad).

[0147] Concerning the judgment of the dew condensation duration, when the ratio to the dew condensation duration of Experimental Example 1 was less than 110[%], it was judged as "◯" (good) since there was no significant increase in the dew condensation duration. On the other hand, when the ratio to the dew condensation duration of Experimental Example 1 was 110[%] or more, it was judged as "×" (poor) since there was a significant increase in the dew condensation duration.

[0148] When the toner remaining rate was judged as "good" and the condensation duration was also judged as "good", the overall judgment was "good". When the toner remaining rate was judged as "good" and the condensation duration was judged as "bad", the overall judgment was "good". When the toner remaining rate was judged as "bad" and the condensation duration was also judged as "bad", the overall judgment was "bad".

[0149] FIG. 11 shows the overall evaluation results of Experimental Examples 1 to 10, with the dipole component of surface free energy γ S p The vertical axis shows the hydrogen bond component of the surface free energy γ S h The graph shows the results.

[0150] In FIG. 11, the dipole component γ S p is 13.4 to 18.1 [mN / m], and the hydrogen bond component γ S h In the range A1 where the force was 5.8 to 35.9 [mN / m], the overall evaluation was either "good" or "good" (Experimental Examples 2 to 6).

[0151] This is because the dipole component γ S p Since the van der Waals force acting between the surface 51 of the test piece 50 and the toner was small, the toner was less likely to adhere to the surface 51. S h This is because the surface 51 of the test piece 50 is highly hydrophilic due to the large diameter of the toner particles, and the toner containing hydrophobic silica (external additive) is less likely to adhere to the surface 51.

[0152] In addition, in FIG. 11, the dipole component γ S p is 13.4 to 15.5 [mN / m], and the hydrogen bond component γ S h In the range A2 in which the strain was 5.8 to 32.7 [mN / m], the overall evaluation was "good" (Experimental Examples 2 to 4).

[0153] The higher the hydrophilicity of the surface 51 of the test piece 50, the less toner adheres to it, but the more likely condensation occurs. S h This keeps the condensation pressure below 32.7 mN / m, thereby shortening the duration of condensation.

[0154] On the other hand, the dipole component γ S p In the range B1 of 28.3 [mN / m] or more, the van der Waals force acting between the toner and surface 51 of test piece 50 is large, so that the toner adheres well to surface 51 of test piece 50 (Experimental Examples 1, 8, and 9).

[0155] In addition, the dipole component γ S p The range B2 where the bond strength is less than 13.4 [mN / m] is a range that cannot be achieved by surface modification of the PPE and PS polymer alloy "Zylon (registered trademark) X352V" by UV irradiation. It can be achieved by attaching a wrapping film or the like (Experimental Examples 7 and 10), but the hydrogen bond component γ S h The force is less than 5.8 [mN / m], and the effect of reducing the toner adhesion cannot be obtained.

[0156] Hydrogen bond component γ of surface free energy of test piece 50 S h In the range B3 where the compressive strength exceeds 35.2 [mN / m], the surface 51 of the test piece 50 is highly hydrophilic, so that condensation is likely to occur, and as a result, the condensation lasts for a long time.

[0157] Hydrogen bond component γ of surface free energy of test piece 50 S h In the region B4 where the surface tension is 1.7 [mN / m] or less, the hydrophobicity is particularly high, so that the toner containing hydrophobic silica (external additive) is likely to adhere (Experimental Examples 1, 7, 8, and 10).

[0158] From the above results, the dipole component γ of the surface free energy of the surface 51 of the test piece 50 S p is set to 13.4 to 18.1 [mN / m], and the hydrogen bond component γS h It can be seen that the toner adhesion can be reduced by setting the pressure to 5.8 to 35.9 [mN / m].

[0159] Furthermore, the dipole component of the surface free energy γ S p is set to 13.4 to 15.5 [mN / m], and the hydrogen bond component γ S h It can be seen that the duration of condensation can be shortened by setting the resistance to 5.8 to 32.7 mN / m.

[0160] <Actual machine evaluation> A developing device 20 having a housing 21 formed from the test piece of each of the first to fifth embodiments and the first to fifth experimental examples was incorporated into an image forming apparatus 1, and a printing test was carried out.

[0161] The image forming device used was a printer "COREFIDO_B842dn" manufactured by Oki Electric Industry Co., Ltd. The printing environment was a temperature of 23[℃] and a relative humidity of 50[%]. The printing pattern was a pattern with a print coverage of 20[%], and the number of printed sheets was 1500[sheets]. The printing paper was A4 size plain paper.

[0162] The number of printed sheets, 1500 [sheets], is the number of printed sheets until the remaining amount of toner in the toner storage unit 26 reaches the toner empty level after toner is replenished from the toner cartridge 30 to the toner storage unit 26 of the developing device 20. When the remaining amount of toner reaches the toner empty level, the control unit 100 of the image forming apparatus 1 displays a toner replacement instruction on the operation unit 93 (FIG. 5).

[0163] In the printing test, when the toner replacement instruction was displayed on the operation unit 93 (FIG. 5), the toner cartridge 30 was removed from the developing device 20, and the receiving port 23 of the developing device 20 was visually observed to determine whether or not there was accumulated toner.

[0164] When no accumulated toner was observed on the inner surface of the receiving port 23 of the developing device 20, the actual machine evaluation was rated as "◯" (good). When accumulated toner was observed on the inner surface of the receiving port 23 of the developing device 20, the actual machine evaluation was rated as "×" (bad). The actual machine evaluations for Experimental Examples 1 to 10 are also shown in FIG. 10.

[0165] In the actual machine evaluation, as in the above-mentioned overall judgment, toner accumulation was observed on the inner surface of the receiving port 23 in Experimental Examples 1 and 7 to 10, but no toner accumulation was observed on the inner surface of the receiving port 23 in Experimental Examples 2 to 6.

[0166] In this way, by modifying the surface of at least the wall portion 24 (the portion where the receiving port 23 is formed) of the housing 21, the dipole component γ S p is set to 13.4 to 18.1 [mN / m], and the hydrogen bond component γ S h By setting the pressure to 5.8 to 35.9 [mN / m], accumulation of toner on the inner surface of receiving port 23 of wall portion 24 can be suppressed, and thus scattering of toner when toner cartridge 30 is replaced can be suppressed.

[0167] Furthermore, the dipole component γ of the surface free energy of the wall 24 S p is set to 13.4 to 15.5 [mN / m], and the hydrogen bond component γ S h By setting the pressure to 5.8 to 32.7 [mN / m], the duration of condensation can be shortened and the effect of moisture absorption by the toner on print quality can be suppressed.

[0168] In this embodiment, at least the wall portion 24 (the portion where the receiving port 23 is formed) of the housing 21 is made of resin, and the dipole component γ S p 13.4 to 18.1 [mN / m] (more preferably 13.4 to 15.5 [mN / m]), and hydrogen bond component γ S hIn the above description, the case where the dipole component γ is set to 5.8 to 35.9 [mN / m] (more preferably, 5.8 to 32.7 [mN / m]) has been described. However, if at least a part of the housing 21 (more preferably, the part where the receiving port 23 is formed) is made of resin, S p and hydrogen bond component γ S h may each be within the above range.

[0169] For example, the entire inner surface of the housing 21 is irradiated with UV light to reduce the dipole component γ S p and hydrogen bond component γ S h may be set within the above ranges. In this case, in addition to the effect of suppressing toner scattering, adhesion of toner to the inner surface of the housing 21 is suppressed, so that the toner in the toner storage unit 26 can be used without waste.

[0170] The surface treatment of the housing 21 of the developing device 20 may include, for example, a step of placing the wall portion 24 on which the receiving port 23 is formed on a flat portion, and a step of irradiating the surface (inner surface) of the receiving port 23 with UV rays of wavelengths 185 [nm] and 254 [nm] at a UV illuminance of 24 [mW / cm] from a UV lamp placed 100 [mm] away. 2 ] for 30 seconds or more (for example, 180 seconds).

[0171] This makes it possible to prevent toner from accumulating on the inner surface of receiving opening 23 and to prevent toner from scattering when replacing toner cartridge 30. Wall portion 24 may be incorporated into housing 21 after surface treatment to form an integrated housing, or wall portion 24 may be surface treated as it is while remaining a part of housing 21.

[0172] The distance from the surface of the receiving port 23 to the UV lamp, the irradiation time, and the UV illuminance are not limited to the above values. S p is 13.4 to 18.1 [mN / m] (more preferably 13.4 to 15.5 [mN / m]), and the hydrogen bond component γ Sh It is sufficient to perform surface treatment so that the compressive strength is 5.8 to 35.9 [mN / m] (more preferably 5.8 to 32.7 [mN / m]).

[0173] Here, the surface modification of at least the wall portion 24 (the portion where the receiving port 23 is formed) of the housing 21 of the developing device 20 has been described, but the surface modification may be performed not only on the wall portion 24 of the developing device 20, but also on at least the bottom portion 32 (the portion where the supply port 33 is formed) of the toner cartridge 30.

[0174] 12 is a schematic diagram showing the toner cartridge 30. During a printing operation, toner is supplied from the supply port 33 of the toner cartridge 30 to the receiving port 23 of the developing device 20, but the toner may adhere to the inner surface of the supply port 33 of the toner cartridge 30. When the printing operation is repeated, the toner accumulates on the inner surface of the supply port 33, as shown by the reference symbol T2.

[0175] The toner thus accumulated in the supply port 33 may adhere to the surface of the shutter 34 of the toner cartridge 30 and scatter into the surroundings when the toner cartridge 30 is replaced as described with reference to FIG.

[0176] Therefore, at least the bottom 32 (the portion where the supply port 33 is formed) of the housing 31 of the toner cartridge 30 is formed of a resin such as a polymer alloy of PPE and PS (for example, "Zylon (registered trademark) X352V"), ​​and the dipole component γ of the surface free energy is reduced by UV irradiation. S p is 13.4 to 18.1 [mN / m] (more preferably 13.4 to 15.5 [mN / m]), and the hydrogen bond component γ S h The surface may be treated so that the surface tension is 5.8 to 35.9 [mN / m] (more preferably 5.8 to 32.7 [mN / m]). This makes it possible to prevent toner from scattering when the toner cartridge 30 is replaced.

[0177] <Advantages of the First Embodiment> As described above, in the developing device 20 of the first embodiment, at least the wall portion 24 (the portion where the receiving port 23 is formed: the receiving portion) of the housing 21 is made of resin, and the dipole component γ S p Since the toner pressure is equal to or greater than 13.4 [mN / m] and equal to or less than 18.1 [mN / m], accumulation of toner on the inner surface of the receiving opening 23 can be suppressed, and scattering of toner when the toner cartridge 30 is replaced can be suppressed.

[0178] In addition, the dipole component of the surface free energy γ S p If the pressure is between 13.4 [mN / m] and 15.5 [mN / m], in addition to the effect of suppressing toner scattering described above, the duration of condensation can be shortened, and the impact of moisture absorption by the toner on print quality can be suppressed.

[0179] In addition, the hydrogen bond component of the surface free energy, γ S h If the toner pressure is 5.8 [mN / m] or more and 35.9 [mN / m] or less (more preferably 5.8 [mN / m] or more and 32.7 [mN / m] or less), the duration of condensation can be further shortened, and the impact of moisture absorption by the toner on print quality can be suppressed.

[0180] In addition, UV irradiation of the resin surface reduces the dipole component γ S p Since the above range can be realized, the effect of suppressing toner scattering can be obtained without complicating the manufacturing process of the developing device 20.

[0181] In addition, the wall 24 of the housing 21 of the developing device 20 is formed from a polymer alloy of PPE and PS, which has a low specific gravity, low water absorption, and is flame retardant, making it possible to reduce the weight of the developing device 20 and improve its dimensional stability and reliability.

[0182] In the toner cartridge (developer container) 30 of the first embodiment, at least the bottom 32 (the portion where the supply port 33 is formed: the supply portion) of the housing 31 is made of resin, and the dipole component γ S p Since the toner pressure is equal to or greater than 13.4 [mN / m] and equal to or less than 18.1 [mN / m], accumulation of toner on the inner surface of the supply port 33 can be suppressed, and scattering of toner when the toner cartridge 30 is replaced can be suppressed.

[0183] In addition, the surface treatment method of the housing 21 of the developing device 20 of the first embodiment is to irradiate ultraviolet light onto at least a part of the surface of the housing 21 made of resin, thereby reducing the dipole component γ S p In order to make the toner adhesion to the surface of the housing 21 lower, the toner adhesion to the surface of the housing 21 can be reduced.

[0184] Variations. 13 is a schematic diagram showing a modified image forming unit 10A. The modified image forming unit 10A includes a developing device 20A, a toner cartridge 30A, and a toner transport section 40 that transports toner from the toner cartridge 30A to the developing device 20A.

[0185] The developing device 20A is configured similarly to the developing device 20 of the first embodiment, except that the developing device 20A receives the toner from the toner transport section 40 into the receiving port .

[0186] The toner cartridge 30A has a housing 131, and a toner storage chamber 135 serving as a developer storage section for storing unused toner is provided inside the housing 131. A waste toner storage chamber 136 for storing waste toner may be provided adjacent to the toner storage chamber 135.

[0187] A supply port 133, which is an opening for discharging toner from a toner storage chamber 135, is formed in a bottom portion (supply portion) 132 of the housing 131. The toner cartridge 30A also has a shutter (not shown) for opening and closing the supply port 133.

[0188] The toner transport section 40 includes a toner duct 41 extending from the toner cartridge 30A to the developing device 20A, a transport spiral 42 provided in the toner duct 41, and a supply motor 45 for rotating the transport spiral 42.

[0189] One end of the toner duct 41 is provided with a receiving portion 43 that is connected to the supply port 133 of the toner cartridge 30A. The other end of the toner duct 41 is connected to the receiving port 23 formed in the wall portion 24 of the housing 21 of the developing device 20A.

[0190] The toner in the toner storage chamber 135 of the toner cartridge 30A is supplied from the supply port 133 to the toner duct 41 via the receiving portion 43 of the toner transport unit 40. The toner supplied to the toner duct 41 is transported by the transport spiral 42 rotated by the supply motor 45, and is supplied to the toner storage unit 26 from the receiving port 23 of the developing device 20.

[0191] The toner cartridge 30A is provided so as to be slidable, for example, in the X direction. When a user operates a lever (not shown), the supply port 133 of the toner cartridge 30A is closed by a shutter, and further the connection between the supply port 133 of the toner cartridge 30A and the receiving portion 43 of the toner transport unit 40 is released. In this state, the toner cartridge 30A can be removed from the developing device 20A by sliding the toner cartridge 30A in the X direction.

[0192] At least the bottom 132 (where the supply port 133 is formed) of the housing 131 of the toner cartridge 30A is preferably made of a resin such as the polymer alloy of PPE and PS described in the first embodiment, and is surface-treated by UV irradiation. In this case, the dipole component γ of the surface free energy Sp is 13.4 to 18.1 [mN / m] (more preferably 13.4 to 15.5 [mN / m]), and the hydrogen bond component γ S h It is preferable that the tension is 5.8 to 35.9 [mN / m] (more preferably 5.8 to 32.7 [mN / m]).

[0193] This configuration suppresses toner accumulation on the inner surface of the supply port 133. This suppresses toner scattering when the toner cartridge 30A is replaced.

[0194] In addition, it is preferable that at least the receiving portion 43 of the toner duct 41 is formed of a resin such as the polymer alloy of PPE and PS described in the first embodiment, and is surface-treated by UV irradiation. In this case, the dipole component γ of the surface free energy S p and hydrogen bond component γ S h It is preferable that each of these is within the above range.

[0195] In this case, toner is prevented from accumulating on the inner surface of the receiving portion 43 of the toner duct 41, and thus scattering of toner is prevented when the toner cartridge 30A is replaced. In addition, the wall portion 24 of the housing 21 of the developing device 20A is formed of a resin such as a polymer alloy of PPE and PS, and the dipole component γ of the surface free energy is reduced by surface treatment using UV irradiation. S p and hydrogen bond component γ S h may each be within the above range.

[0196] Although the preferred embodiments have been specifically described above, the present disclosure is not limited to the above-described embodiments, and various improvements and modifications can be made.

[0197] The present disclosure can also be used in image forming apparatuses that form images using an electrophotographic system, such as copying machines, facsimiles, and multifunction machines.

[0198] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) a housing having a receiving portion formed with a receiving port for receiving a developer and accommodating the developer; a developer carrier disposed within the housing and carrying the developer; having The surface free energy of the surface of the receiving part formed of resin is defined as the dispersion component γ S d and the dipole component γ S p and hydrogen bond component γ S h When expressed as the sum of S p is greater than or equal to 13.4 [mN / m] and less than or equal to 18.1 [mN / m] A developing device characterized by the above. (Appendix 2) The dipole component γ of the surface free energy of the surface of the receiving portion S p is greater than or equal to 13.4 [mN / m] and less than or equal to 15.5 [mN / m] 2. The developing device according to claim 1 . (Appendix 3) The hydrogen bond component γ of the surface free energy of the surface of the receiving portion S h is greater than or equal to 5.8 [mN / m] and less than or equal to 35.9 [mN / m] 3. The developing device according to claim 1 or 2. (Appendix 4) The hydrogen bond component γ of the surface free energy of the surface of the receiving portion S h is greater than or equal to 5.8 [mN / m] and less than or equal to 32.7 [mN / m] 4. The developing device according to claim 1, (Appendix 5) The receiving portion is surface-modified by ultraviolet irradiation. 5. The developing device according to claim 1, (Appendix 6) The receiving part is made of a polymer alloy of PPE and PS. 6. The developing device according to claim 1, (Appendix 7) a housing having a supply section formed with a supply port for supplying a developer and accommodating the developer; an opening / closing member for opening and closing the supply port; having The surface free energy of the surface of the supply part formed of resin is defined as the dispersion component γ S d and the dipole component γ S p and hydrogen bond component γ S h When expressed as the sum of S p is greater than or equal to 13.4 [mN / m] and less than or equal to 18.1 [mN / m] A developer container comprising: (Appendix 8) The dipole component γ of the surface free energy of the surface of the supply portion S p is greater than or equal to 13.4 [mN / m] and less than or equal to 15.5 [mN / m] 8. The developer container according to claim 7, (Appendix 9) The hydrogen bond component γ of the surface free energy of the surface of the supply portion S h is greater than or equal to 5.8 [mN / m] and less than or equal to 35.9 [mN / m] 9. The developer container according to claim 7 or 8, (Appendix 10) The hydrogen bond component γ of the surface free energy of the surface of the housing S h is greater than or equal to 5.8 [mN / m] and less than or equal to 32.7 [mN / m] 10. The developer container according to claim 7, (Appendix 11) The supply part is surface-modified by ultraviolet irradiation. 11. The developer container according to claim 7, (Appendix 12) The supply part is made of a polymer alloy of PPE and PS. 12. The developer container according to claim 7, (Appendix 13) A developing device according to any one of claims 1 to 6, a developer container for supplying developer to the receiving port of the developing device; An image forming apparatus comprising: (Appendix 14) A developing device; The developer container according to any one of claims 7 to 12, which supplies a developer to the developing device from the supply port. An image forming apparatus comprising: (Appendix 15) In a developing device that receives a developer from an inlet formed in a receiving portion and stores the developer in a housing, by irradiating ultraviolet light onto at least a part of a surface of the housing formed of a resin, The surface free energy of the surface is the dispersion component γ S d and the dipole component γ S p and hydrogen bond component γ S h When expressed as the sum of S p The value should be between 13.4 [mN / m] and 18.1 [mN / m]. A surface treatment method for a housing of a developing device. (Appendix 16) The dipole component γ of the surface free energy of the surface of the housing S p is greater than or equal to 13.4 [mN / m] and less than or equal to 15.5 [mN / m] 16. The surface treatment method for a housing of a developing device according to claim 15. (Appendix 17) The hydrogen bond component γ of the surface free energy of the surface of the housing S h is greater than or equal to 5.8 [mN / m] and less than or equal to 35.9 [mN / m] 17. The surface treatment method for a housing of a developing device according to claim 15 or 16. (Appendix 18) The hydrogen bond component γ of the surface free energy of the surface of the housing S h is greater than or equal to 5.8 [mN / m] and less than or equal to 32.7 [mN / m] 18. The surface treatment method for a housing of a developing device according to any one of claims 15 to 17. [Explanation of symbols]

[0199] 1 Image forming apparatus, 10, 10A Image forming unit (image forming section), 11 Photoconductor drum (image carrier), 12 Charging roller (charging member), 13 Development roller (developer carrier), 14 Supply roller (supply member), 15 Development blade (regulating member), 18 Print head (exposure device), 19 Transfer roller (transfer member), 20, 20A Development device, 21 Housing (first housing), 22 Cartridge mounting section, 23 Receiving port (opening, first opening), 24 Wall section (receiving section), 25 Seal member, 26 Toner storage section, 27 Toner remaining amount detection bar, 30, 30A Toner cartridge (developer container), 31 Housing (second housing), 32 Bottom section (supply section), 33 Supply port (opening, second opening), 34 shutter (opening / closing member), 35 toner storage chamber, 40 toner transport section (developer transport section), 41 toner duct (developer transport path), 42 transport spiral (transport member), 43 receiving section, 50 test piece, 51 surface, 60 medium supply section, 70 fixing device, 80 medium discharge section, 93 operation section, 94 sensor group, 100 control section, 101 print control section, 131 housing (second housing), 132 bottom (supply section), 133 supply port (opening, second opening), 135 toner storage chamber.

Claims

1. a housing having a receiving portion formed with a receiving port for receiving a developer and accommodating the developer; a developer carrier disposed within the housing and carrying the developer; having The surface free energy of the surface of the receiving part formed of resin is defined as the dispersion component γ Ｓ ｄ and the dipole component γ Ｓ ｐ and hydrogen bond component γ Ｓ ｈ When expressed as the sum of Ｓ ｐ is 13.4 [mN / m] or more and 18.1 [mN / m] or less. A developing device characterized by the above.

2. The dipole component γ of the surface free energy of the surface of the receiving portion Ｓ ｐ is 13.4 [mN / m] or more and 15.5 [mN / m] or less.

2. The developing device according to claim 1,

3. The hydrogen bond component γ of the surface free energy of the surface of the receiving portion Ｓ ｈ is 5.8 [mN / m] or more and 35.9 [mN / m] or less.

2. The developing device according to claim 1,

4. The hydrogen bond component γ of the surface free energy of the surface of the receiving portion Ｓ ｈ is 5.8 [mN / m] or more and 32.7 [mN / m] or less 2. The developing device according to claim 1,

5. The surface of the receiving portion is modified by ultraviolet irradiation.

2. The developing device according to claim 1,

6. The receiving portion is made of a polymer alloy of PPE and PS.

2. The developing device according to claim 1,

7. a housing having a supply section formed with a supply port for supplying a developer and accommodating the developer; an opening / closing member for opening and closing the supply port; having The surface free energy of the surface of the supply part formed of resin is defined as the dispersion component γ Ｓ ｄ and the dipole component γ Ｓ ｐ and hydrogen bond component γ Ｓ ｈ When expressed as the sum of Ｓ ｐ is 13.4 [mN / m] or more and 18.1 [mN / m] or less. A developer container comprising:

8. The dipole component γ of the surface free energy of the surface of the supply portion Ｓ ｐ is 13.4 [mN / m] or more and 15.5 [mN / m] or less.

8. The developer container according to claim 7,

9. The hydrogen bond component γ of the surface free energy of the surface of the supply portion Ｓ ｈ is 5.8 [mN / m] or more and 35.9 [mN / m] or less.

8. The developer container according to claim 7,

10. The hydrogen bond component γ of the surface free energy of the surface of the supply portion Ｓ ｈ is 5.8 [mN / m] or more and 32.7 [mN / m] or less 8. The developer container according to claim 7,

11. The surface of the supply portion is surface-modified by ultraviolet irradiation.

8. The developer container according to claim 7,

12. The supply part is made of a polymer alloy of PPE and PS.

8. The developer container according to claim 7,

13. A developing device according to any one of claims 1 to 6, a developer container for supplying developer to the receiving port of the developing device; An image forming apparatus comprising:

14. A developing device; The developer container according to claim 7, which supplies the developer to the developing device through the supply port. An image forming apparatus comprising:

15. In a developing device that receives a developer from an inlet formed in a receiving portion and stores the developer in a housing, by irradiating ultraviolet light onto at least a part of a surface of the housing formed of a resin, The surface free energy of the surface is the dispersion component γ Ｓ ｄ and the dipole component γ Ｓ ｐ and hydrogen bond component γ Ｓ ｈ When expressed as the sum of Ｓ ｐ is set to be 13.4 [mN / m] or more and 18.1 [mN / m] or less. A surface treatment method for a housing of a developing device.

16. The dipole component γ of the surface free energy of the surface of the housing Ｓ ｐ is 13.4 [mN / m] or more and 15.5 [mN / m] or less. The surface treatment method for a housing of a developing device according to claim 15.

17. The hydrogen bond component γ of the surface free energy of the surface of the housing Ｓ ｈ is 5.8 [mN / m] or more and 35.9 [mN / m] or less.

17. The method for treating the surface of a housing of a developing device according to claim 15 or 16.

18. The hydrogen bond component γ of the surface free energy of the surface of the housing Ｓ ｈ is 5.8 [mN / m] or more and 32.7 [mN / m] or less 17. The method for treating the surface of a housing of a developing device according to claim 15 or 16.

Images