Patent Application
20180364617
This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2017-118001 filed Jun. 15, 2017.
The present invention relates to a transfer device and an image forming apparatus.
According to an aspect of the invention, a transfer device includes a holding body, a transfer body, and a setting portion. The holding body holds multiple layers including a base layer formed of a toner having a mass larger than a threshold. The toner is electrically charged by a charging device. The transfer body transfers the layers on the holding body to a recording medium. The setting portion sets the charging device so that the charging device electrically charges a toner immediately after being transferred to the holding body with a larger amount of electric charges when the base layer is located uppermost on the holding body, than when the base layer is located other than uppermost on the holding body.
Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein:
Examples of a transfer device and an image forming apparatus according to a first exemplary embodiment of the present invention are described with reference to
As illustrated in
The image forming apparatus 10 includes a cooling portion 20, which cools a sheet member P on which an image is formed, a correcting portion 22, which corrects bending of a sheet member P, and an image inspecting portion 24, which inspects an image formed on a sheet member P.
The image forming apparatus 10 also includes a reverse path 26, which reverses a sheet member P having an image formed on its top surface and transports the sheet member P again toward the image forming unit 12 to form images on both surfaces of the sheet member P.
The image forming apparatus 10 having the above structure forms an image (toner image) formed by the image forming unit 12 on the top surface of a sheet member P transported along the transport path 16. The sheet member P having an image famed thereon passes through the cooling portion 20, the correcting portion 22, and the image inspecting portion 24 in this order to be discharged to the outside of the apparatus.
When an image is to be formed on the back surface of a sheet member P, a sheet member P having an image formed on its top surface is transported along the reverse path 26 and the image forming unit 12 forms an image again on the back surface of the sheet member P.
The image forming unit 12 includes multiple toner layer forming portions 30, which respectively form toner layers of various colors, a transfer belt 50, which holds a toner image formed from one or more toner layers, and a transfer portion 14, which transfers a toner image to a sheet member P. The image forming unit 12 also includes a setting portion 58 (see
The multiple toner layer forming portions 30 form toner layers of different colors. In the present exemplary embodiment, the toner layer forming portions 30 are prepared for five colors of yellow (Y), magenta (M), cyan (C), black (K), and white (W). Reference characters Y, M, C, K, and W appended to the reference numerals in
In the following description, the characters Y, M, C, K, and W appended to the reference numerals are omitted unless yellow (Y), magenta (M), cyan (C), black (K), and white (W) need to be distinguished from each other. Hereinbelow, yellow (Y), magenta (M), cyan (C), and black (K) may be collectively referred to as “non-white colors”.
The toner layer forming portions 30 for various colors basically have the same structure except for using different color toners. As illustrated in
Each image carrier 40 for the corresponding color is grounded and touches the rotating transfer belt 50 (described in detail below). As illustrated in
The toner layer forming portion 30W disposed on the upstream side of the non-white color toner layer forming portions 30Y, 30M, 30C, and 30K in the sheet transport direction may be also referred to as a “toner layer forming portion 30W-A” for illustration convenience. On the other hand, the toner layer forming portion 30W disposed on the downstream side of the non-white color toner layer forming portions 30Y, 30M, 30C, and 30K in the sheet transport direction may be also referred to as a “toner layer forming portion 30W-B” for illustration convenience.
As illustrated in
As illustrated in
The following describes toners used in the developing devices 46, the transfer belt 50, serving as an example of a holding body, the transfer portion 14, serving as an example of a transfer body, the voltage application members 48 (see
The developing devices 46W-A and 46W-B employ a white toner 200 (also referred to as “a W toner”, below), and the developing devices 46Y, 46M, 46C, and 46K employ color toners 300 for non-white colors. Now, the white toner 200 and the color toners 300 are described.
The white toner 200 is used on the sheet member P as a base coat for non-white colors. Specifically, a solid layer (solid image) of the white toner 200 is formed on a sheet member P as a base coat for non-white colors to enhance color reproduction of the toner image.
When the sheet member P is a paper medium, a W toner layer, a K toner layer, a C toner layer, a M toner layer, and a Y toner layer are superposed one on top of another in this order on the sheet member P, which is a paper medium (see
As illustrated in
In the state where the spherical pigment 210 is placed on a flat surface 500, a lateral dimension X1 and a front-rear dimension Z1 of the spherical pigment 210, viewed from the top in
The white toner 200 containing the spherical pigment 210 is also spherical in the same manner as the spherical pigment 210. Thus, when the white toner 200 is placed on the flat surface 500, a lateral dimension A1 and a front-rear dimension B1 of the white toner 200, viewed from the top in
The volumetric average particle diameter of the spherical pigment 210 or the white toner 200 is measured by using, for example, Coulter counter TAII (from Nikkaki Bios Co., Ltd.) or multisizer II (from Nikkaki Bios Co., Ltd.). Specifically, within a particle range (channel) separated on the basis of the particle size distribution measured with this measuring instrument, the cumulative distribution is plotted from the smaller diameter with respect to the volume, and the particle diameter (D50v) of the cumulative percentage of 50% is used as a volumetric average particle diameter. Other volumetric average particle diameters below are measured similarly.
The standard volumetric average particle diameter of the spherical pigment 210 falls within a range of approximately 200 nm to 300 nm. The standard volumetric average particle diameter of the white toner 200 falls within a range of approximately 4 μm to 14 μm.
In the present exemplary embodiment, the volumetric average particle diameter of the white toner 200 is 8.5 μm, and the specific gravity of the white toner 200 is 1.6 g/cm3. Thus, the average mass (an example of mass) of the white toner 200 is 0.51×10−9 g.
As illustrated in
In the state where the spherical pigment 310 is placed on the flat surface 500, a lateral dimension X2 and a front-rear dimension Z2 of the spherical pigment 310, viewed from the top in
Similarly to the pigment 310, the color toner 300 containing the pigment 310 is also spherical. Thus, when the color toner 300 is placed on the flat surface 500, a lateral dimension A2 and a front-rear dimension B2 of the color toner 300, viewed from the top in
The volumetric average particle diameter of the pigment 310 falls within the range of approximately 50 nm to 150 nm. The volumetric average particle diameter of the color toner 300 falls within the range of 3 μm to 9 μm. When the volumetric average particle diameter exceeds 9 μm, the image may have a low resolution. On the other hand, when the volumetric average particle diameter falls below 3 μm, the toner may be charged insufficiently, and the developed image may have low quality.
As described above, the color toner 300 includes a spherical pigment 210, less electrically conductive than the spherical pigment 210 of the white toner 200. Thus, the color toner 300 is more easily charged than the white toner 200. Specifically, the color toner 300 has higher chargeability (electric-charge bearability) than the white toner 200. In other words, the white toner 200 has lower chargeability than the color toner 300.
Here, in the present exemplary embodiment, for each of the Y toner, the M toner, and the C toner, a toner having a specific gravity of 1.1 g/cm3 and a volumetric average particle diameter of 4.7 μm is used. For the K toner, a toner having a specific gravity of 1.2 g/cm3 and a volumetric average particle diameter of 4.7 μm is used. Thus, the Y toner, the M toner, and the C toner have a mass of 0.6×10−10 g, and the K toner has a mass of 0.65×10−10 g.
The color toner 300 may contain a compound formed from a divalent or polyvalent metallic element. The compound is added as, for example, a coagulant to form the color toner 300 by emulsion polymerization aggregation. The content of the compound in the color toner 300 falls within a range of, for example, 0.05 percent by mass to 2 percent by mass.
As illustrated in
The transfer portion 14 includes multiple rollers 32, around which the transfer belt 50 is wound, and first transfer rollers 52 for various colors, which transfer the toner layers formed on the image carriers 40 for the various colors to the transfer belt 50. The transfer portion 14 also includes a second transfer portion 54, which transfers the toner image transferred to the transfer belt 50 to the sheet member P.
Multiple rollers 32 include a roller 32D disposed on a first end (on the right side) in the apparatus width direction. The roller 32D rotates the transfer belt 50 in the direction of arrow A (counterclockwise in the drawing) with a rotational force transmitted from a motor, not illustrated. In the present exemplary embodiment, the roller 32D is a cylindrical metal roller having an outer diameter of 28 mm.
The multiple rollers 32 include a roller 32B, around which the lower end vertex forming an obtuse angle of the transfer belt 50 taking an obtuse triangle position is wound. The roller 32B faces the second transfer portion 54 with the transfer belt 50 interposed therebetween. A transfer voltage is applied to the roller 32B. In the present exemplary embodiment, the roller 32B is an elastic roller having an outer diameter of 28 mm. The roller 32B has a surface resistance of 7.3 log ohm/sq. The roller 32B has a surface hardness of 53 degrees in Asker C hardness.
The multiple rollers 32 include a roller 32T on the upstream side of and adjacent to the roller 32B in the direction in which the transfer belt 50 rotates (hereinafter referred to as “a belt rotation direction”). The roller 32T applies a tension to the transfer belt 50. Specifically, a slope portion of the transfer belt 50 is wound around the roller 32T. The slope portion of the transfer belt 50 tilts from the horizontal direction. In the present exemplary embodiment, the roller 32T is a cylindrical metal roller having an outer diameter of 28 mm.
As illustrated in
As illustrated in
In the present exemplary embodiment, the elastic belt 64 is a rubber belt having a thickness of 450 μm and a perimeter of 40 mm. The elastic belt 64 has a volume resistance of 9.2 log ohm.
The roller 66 is grounded and disposed so as to hold the transfer belt 50 and the elastic belt 64 between the roller 66 and the roller 32B. In the present exemplary embodiment, the roller 66 is an elastic roller having an outer diameter of 28 mm. The roller 66 has a resistance of 6.3 log ohm.
The roller 68 is located on the downstream side of the roller 66 in the direction in which the sheet member P is transported along the transport path 16 (hereinafter referred to as “a sheet transport direction”). In the present exemplary embodiment, the roller 68 is a cylindrical metal roller having an outer diameter of 20 mm.
In this structure, a sheet member P transported while being held between the transfer belt 50 and the second transfer portion 54 is pressed against the transfer belt 50. When a transfer voltage is applied to the roller 32B, a transfer electric field is formed between the roller 32B and the roller 66 of the second transfer portion 54. This transfer electric field transfers the toner image on the transfer belt 50 to the sheet member P that is being transported.
As illustrated in
In this structure, when each voltage application member 48 applies a transfer voltage to the corresponding first transfer roller 52, a transfer electric field is formed between the first transfer roller 52 and the image carrier 40. The toner layer on the image carrier 40 is thus transferred to the transfer belt 50 with the transfer electric field, and the transfer belt 50 holds the toner image formed from one or more toner layers.
The setting portion 58 sets the amount of electric charges of the toner so that a toner immediately after being transferred to the transfer belt 50 is electrically charged with a larger amount of electric charges when a base layer formed of a toner having a mass equal to or larger than a threshold is located uppermost on the transfer belt 50, than when a base layer formed of a toner having a mass equal to or larger than a threshold is located other than uppermost on the transfer belt 50.
Specifically, the setting portion 58 sets the amount of electric charges of the toner immediately after a base layer located uppermost on the transfer belt 50 is transferred to the transfer belt 50 (referred to as “first amount of electric charges”, below) to be larger than the amount of electric charges of the toner immediately after a base layer located other than uppermost on the transfer belt 50 is transferred to the transfer belt 50 (referred to as “second amount of electric charges”, below).
In the present exemplary embodiment, the threshold of the mass of the toner (toner particles) is set at, for example, 0.2×10−9 g.
Thus, the base layer located uppermost on the transfer belt 50 is a toner layer formed of a W toner transferred to the transfer belt 50 by the first transfer roller 52W-B. On the other hand, the base layer located other than uppermost on the transfer belt 50 is a toner layer formed of a W toner transferred to the transfer belt 50 by the first transfer roller 52W-A. Specifically, the “base layer” refers to the W toner layer in the present exemplary embodiment.
In addition, “the amount of electric charges of the toner of the W toner layer immediately after being transferred to the transfer belt 50” refers to the amount of electric charges of the toner of the toner layers transferred to the transfer belt 50 by the first transfer rollers 52W-A and 52W-B in the state of not being affected by the transfer electric field of other first transfer rollers 52. Specifically, the amount of electric charges of the toner of the W toner layer transferred by the first transfer roller 52W-A is an amount of electric charges of the toner of the toner layer before the toner layer enters a space (transfer nip) between the image carrier 40Y and the first transfer roller 52Y.
The amount of electric charges μC/g of the toner on the transfer belt 50 may be detected by using a known technology. For example, the amount of electric charges of the toner may be measured by a charge/particle-size spectrometer (E-SPART ANALYZER) from HOSOKAWA MICRON CORPORATION. The amount of electric charges per unit mass may be measured by a blow-off measurement system, instead. In the present exemplary embodiment, the amount of electric charges is measured by the E-SPART method.
Hereinbelow, which device the setting portion 58 specifically controls to render the first amount of electric charges larger than the second amount of electric charges is described.
To render the first amount of electric charges larger than the second amount of electric charges, the setting portion 58 sets the voltage application members 48W-A and 48W-B so that the transfer voltage applied to the first transfer roller 52W-B is larger than the transfer voltage applied to the first transfer roller 52W-A.
A voltage substantially equal to the transfer voltage applied to the first transfer roller 52W-A is constantly applied to the first transfer rollers 52Y, 52M, 52C, and 52K.
When the base layer is located uppermost on the transfer belt 50, the amount of electric charges of the toner of the base layer immediately before the base layer is transferred to the sheet member P by the second transfer portion 54 is a third amount of electric charges. When the base layer is located other than uppermost on the transfer belt 50, the amount of electric charges of the toner of the base layer immediately before the base layer is transferred to the sheet member P by the second transfer portion 54 is a fourth amount of electric charges.
When the setting portion 58 sets the first amount of electric charges to be larger than the second amount of electric charges, the setting portion 58 sets the voltage application members 48W-A and 48W-B so that the third amount of electric charges is substantially equal to the fourth amount of electric charges.
Here, “the amount of electric charges of the toner of the base layer immediately before the base layer is transferred to the sheet member P” is the amount of electric charges of the toner of the toner layer transferred to the transfer belt 50 after being affected by the transfer electric field of other first transfer rollers 52 and before being transferred to the sheet member P by the second transfer portion 54. Specifically, the amount of electric charges of the toner of the base layer transferred to the first transfer roller 52W-A is an amount of electric charges of the toner after the toner has passed through the space between the image carriers 40Y, 40M, 40C, 40K, and 40W-B and the first transfer rollers 52Y, 52M, 52C, 52K, and 52W-B.
The state where “the third amount of electric charges is substantially equal to the fourth amount of electric charges” is the state where the third amount of electric charges falls within the range of ±10% of the fourth amount of electric charges.
Now, the effects of the image forming apparatus 10 are described in comparison with an image forming apparatus 910 according to a comparative example. Firstly, the structure of the image forming apparatus 910 according to a comparative example, particularly, the portions of the image forming apparatus 910 according to a comparative example that differ from those of the image forming apparatus 10 according to the present exemplary embodiment are described. Then, the effects of the image forming apparatus 910 according to the comparative example and the image forming apparatus 10 according to the present exemplary embodiment are described.
As illustrated in
Regardless of the mass of a toner, the setting portion 958 sets the voltage application members 48W-A and 48W-B to apply, to the first transfer rollers 52W-A and 52W-B, the transfer voltage substantially equal to the transfer voltage that the image forming apparatus 10 applies to the first transfer roller 52W-A. Specifically, the image forming apparatus 910 constantly applies, to the first transfer rollers 52W-A, 52Y, 52M, 52C, 52K, and 52W-B, the transfer voltage substantially equal to the transfer voltage that the image forming apparatus 10 applies to the first transfer roller 52W-A.
Thus, in the image forming apparatus 910, the above-described first amount of electric charges is substantially equal to the second amount of electric charges.
Now, the case where the image forming apparatus 910 having the above structure outputs an image using the toner layer forming portions 30Y, 30M, 30C, 30K, and 30W-8 is described.
When the toner layer forming portions 30Y, 30M, 30C, 30K, and 30W-B (see
As illustrated in
Now, the reason why only the W toner scatters in the image forming apparatus 910 is considered.
In the image forming apparatus 10, on the other hand, the setting portion 58 sets the voltage application members 48W-A and 48W-B so that a transfer voltage applied to the first transfer roller 52W-B is larger than a transfer voltage applied to the first transfer roller 52W-A.
Thus, in the image forming apparatus 10, the amount of electric charges of the toner of the W toner layer transferred by the first transfer roller 52W-B is larger than the amount used in the image forming apparatus 910. In other words, in the image forming apparatus 10, adhesive power with which the W toner layer transferred to the transfer belt 50 by the first transfer roller 52W-B adheres to the transfer belt 50 is stronger than in the case of the image forming apparatus 910.
The image forming apparatus 10 has stronger adhesive power with which the W toner layer transferred to the transfer belt 50 by the first transfer roller 52W-B adheres to the transfer belt 50. Thus, scattering of the W toner on the transfer belt 50 is suppressed compared to the case of the image forming apparatus 910.
In the image forming apparatus 10, suppressing the scattering of the W toner on the transfer belt 50 reduces the quality degradation of the images transferred to the sheet member P compared to the case of the image forming apparatus 910.
In the image forming apparatus 10, the setting portion 58 sets the voltage application members 48W-A and 48W-B so that the third amount of electric charges is substantially equal to the fourth amount of electric charges when the setting portion 58 sets the first amount of electric charges to be larger than the second amount of electric charges.
As described above, the third amount of electric charges is the amount of electric charges of the toner of the W toner layer immediately before the W toner layer (base layer) located uppermost on the transfer belt 50 and transferred to the transfer belt 50 by the first transfer roller 52W-B is transferred to the sheet member P by the transfer portion 14. As described above, the fourth amount of electric charges is the amount of electric charges of the toner of the W toner layer immediately before the W toner layer (base layer) transferred to the transfer belt 50 by the first transfer roller 52W-A is transferred to the sheet member P by the transfer portion 14.
When a paper medium is used as the sheet member P, the W toner layer, the K toner layer, the C toner layer, the M toner layer, and the Y toner layer are superposed in this order on the sheet member P, which is a paper medium (see
On the other hand, when a transparent film is used as the sheet member P, the K toner layer, the C toner layer, the M toner layer, the Y toner layer, and the W toner layer are superposed in this order on the sheet member P, which is a film (see
Here, the third amount of electric charges and the fourth amount of electric charges are substantially equal to each other. Thus, the hue of the W toner layer transferred by the first transfer roller 52W-B and then transferred to the sheet member P and the hue of the W toner layer transferred by the first transfer roller 52W-A and then transferred to the sheet member P are substantially equal to each other, unlike in the case where the third amount of electric charges and the fourth amount of electric charges differ from each other. Specifically, the hues match each other when the amounts of electric charges of toners are substantially equal to each other.
Thus, the hue of the toner image reproduced by using a paper medium as the sheet member P and the hue of the toner image reproduced by using a transparent film as the sheet member P approximate each other, compared to the case where the third amount of electric charges and the fourth amount of electric charges differ from each other.
Examples of a transfer device and an image forming apparatus according to a second exemplary embodiment of the present invention are described with reference to
As illustrated in
A silver toner 100 (hereinafter may be referred to as “V toner”) is used in a developing device 46V for the toner layer forming portion 30V.
As illustrated in
As illustrated in
When the flat pigment 110 illustrated in
Since the flat pigment 110 has a flat shape, the silver toner 100 containing the flat pigment 110 also has a flat shape, following the contour of the flat pigment 110. Thus, when the silver toner 100 is placed on the flat surface 500 and viewed from the side, the silver toner 100 has a dimension A3 in the lateral direction longer than the dimension C3 in the vertical direction, as illustrated in
When the silver toner 100 illustrated in
Here, the relationship A3≥B3>C3 holds true, where A3 denotes the maximum length (maximum diameter) of the silver toner 100 viewed from the top, B3 denotes an orthogonal length orthogonal to the maximum length A3, and C3 denotes a thickness of the silver toner 100 viewed from the top (dimension in the vertical direction).
In the present exemplary embodiment, an example used as the V toner has a specific gravity of 1.6 g/cm3, a maximum length A3 of 12 μm, an orthogonal length B3 of 12 μm, and a thickness C3 of 2 μm. Thus, the V toner (toner particle) has a mass of 0.24×10−9 g. Specifically, the mass of the V toner exceeds the threshold (0.2×10−9 g).
The maximum length A3, the orthogonal length B3, and the thickness C3 are obtained by observing the toner in an enlarged manner using a color laser microscope “VK-9700” (from KEYENCE CORPORATION) and by calculating the maximum length of the toner flat surface using image processing software.
The silver toner 100 is used as a base coat for the non-white colors on the sheet member P. Specifically, the solid layer (solid image) of the silver toner 100 is formed on the sheet member P as a base coat for the non-white colors to provide glossiness to the toner image.
Thus, when the sheet member P is a paper medium, the V toner layer, the K toner layer, the C toner layer, the M toner layer, and the Y toner layer are superposed in this order on the sheet member P, which is a paper medium (see
A case is described where this structure forms, on a paper medium serving as the sheet member P, a toner image including a V toner layer for use as a base coat for the Y, M, C, and K color toners 300 to enhance the image glossiness.
Toner layers formed by the toner layer forming portions 30Y, 30M, 30C, 30K, and 30V are first-transferred to the rotating transfer belt 50 by the first transfer rollers 52 (
Here, the uppermost one of the toner layers disposed on the transfer belt 50 and constituting the toner images is the V toner layer.
Thus, the setting portion 58 sets the voltage application members 48W-B and 48W-A so that a transfer voltage to the first transfer roller 52W-B is larger than a transfer voltage applied to the first transfer roller 52W-A.
Other operations are the same as those in the case of the first exemplary embodiment.
Examples of a transfer device and an image forming apparatus according to a third exemplary embodiment of the present invention are described with reference to
As illustrated in
The setting portion 558 sets the developing devices 46W-A and 46W-B so that the first amount of electric charges is larger than the second amount of electric charges. Specifically, the setting portion 558 sets the developing devices 46W-A and 46W-B so that the amount of electric charges of the toner used for developing an electrostatic latent image formed on the image carrier 40W-B is larger than the amount of electric charges of the toner used for developing an electrostatic latent image formed on the image carrier 40W-A.
The image carrier 40W-A is an example of a second image carrier, and the image carrier 40W-B is an example of a first image carrier. The electrostatic latent image formed on the image carrier 40W-A is an example of a second latent image. The electrostatic latent image formed on the image carrier 40W-B is an example of a first latent image. The developing device 46W-A is an example of a second developing device, and the developing device 46W-B is an example of a first developing device.
More specifically, the setting portion 558 sets a number of times of rotation of an agitation auger (member that agitates a developer G to frictionally charge a toner), which is disposed in the developing device 46W-B to agitate the toner and a carrier, to be larger than the number of times of rotation of an agitation auger, which is disposed in the developing device 46W-A. The agitation augers are not illustrated. Thus, the setting portion 558 sets the amount of electric charges of the toner for developing an electrostatic latent image formed on the image carrier 40W-B to be larger than the amount of electric charges of the toner for developing an electrostatic latent image formed on the image carrier 40W-A.
In the image forming apparatus 510, the setting portion 558 sets the developing devices 46W-A and 46W-B so that the above-described third amount of electric charges is substantially equal to the fourth amount of electric charges.
Other effects are the same as those of the first exemplary embodiment.
Although specific exemplary embodiments of the present invention are described in detail, the present invention is not limited to these exemplary embodiments. It is clear to persons having ordinary skill in the art that the present invention may be embodied in various other exemplary embodiments within the scope of the present invention. For example, in the above-described exemplary embodiments, each of the setting portions 58 and 558 sets the first amount of electric charges to be larger than the second amount of electric charges when the mass of the toner of the W toner layer (base layer) transferred by the first transfer roller 52W-B and the mass of the toner of the W toner layer (base layer) transferred by the first transfer roller 52W-A are equal to or exceeds the threshold. Alternatively, each of the setting portions 58 and 558 may set the first amount of electric charges to be larger than the second amount of electric charges when the toner of the W toner layer (base layer) transferred by the first transfer roller 52W-B and the toner of the W toner layer (base layer) transferred by the first transfer roller 52W-A contain a pigment formed from metal or a metallic oxide. The mass of the toner containing a pigment formed from metal or a metallic oxide is larger than the mass of the color toner 300. Thus, the similar effects described in the exemplary embodiments are exerted here.
In the above-described exemplary embodiment, the volumetric average particle diameter is used to calculate the mass of the white toner 200 or the color toners 300. Instead, the particle diameter averaged by the number of particles may be used to calculate the mass. The particle diameter averaged by the number of particles may be measured by a charge spectrometer (E-Spart ANALYZER) from HOSOKAWA MICRON CORPORATION. This is a measuring device that detects the movement of particles in the aerial vibration field in the electric field by a laser Doppler method and concurrently measures the amount of electric charges and the particle diameter of individual particles from the data. The data of 3000 toner particles are input to this device and the average of the individual particle diameter data is the particle diameter averaged by the number of particles.
In the third exemplary embodiment, the amount of electric charges of the toner is changed by changing the number of times of rotation of an agitation auger. However, the amount of electric charges of the toner may be changed by changing, for example, the carrier of the developer G.
In each of the above-described exemplary embodiment, the present application is described using a tandem image forming apparatus 10 that develops a latent image on a single image carrier 40 with a single developing device 46. Instead, the image forming apparatus 10 may be a revolver (6 cycle) image forming apparatus that develops a latent image on a single image carrier with multiple developing devices.
The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-118001 | Jun 2017 | JP | national |
