JP2015148756A - image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To orient flat surfaces of flat pigments irregularly with respect to a surface of a recording medium.SOLUTION: As the number of layers Am of a metal-color toner Gm is increased, toner orientation decreases, and reflection surfaces 120A of flat pigments 120 are likely to be oriented in a direction which crosses a direction along a sheet surface PA of a sheet member P and the reflection surfaces 120A are likely to be oriented irregularly. When the reflection surfaces 120A of the flat pigments 120 are oriented in the direction which crosses the direction along the sheet surface PA of the sheet member P and the reflection surfaces 120A are oriented irregularly, light is reflected in random directions and regular reflectance is reduced while diffuse reflectance is increased, thereby improving luminosity.

Description

  The present invention relates to an image forming apparatus.

  Patent Document 1 discloses an image forming apparatus in which a gold toner image developed on a photoconductor and a toner image of a color other than the gold toner image are stacked on an image carrier and then fixed to form an image. Yes. In this prior art, a gold toner image is laminated on an image carrier on another color toner image.

  In Patent Document 2, a full-color toner image of a gold toner developed on a photoreceptor of an image forming apparatus capable of forming an image including a gold image by electrophotography and a color other than the gold toner is laminated on an intermediate transfer member. Subsequently, an image forming apparatus is disclosed in which a full color toner image is transferred to an image carrier and fixed to form an image. In this prior art, after a gold toner image, which is an image formed with gold toner, is laminated on an intermediate transfer member, a toner image formed from at least one color toner other than the gold toner is laminated on the gold toner image. Has been.

JP 2006-317632 A JP 2006-317633 A

  An object of the present invention is to make the flat surface of a flat pigment (flat pigment) an irregular posture with respect to the paper surface of a recording medium.

  The invention of claim 1 includes a first image forming unit using a toner containing a flat pigment, a second image forming unit using a toner containing no flat pigment, and a flat pigment formed by the first image forming unit. A toner image holding body that holds a toner image and a toner image that does not include a flat pigment formed by the second image forming unit, and the toner image includes the flat pigment held by the toner image holding body. When the toner layer number is Am, and the toner layer number of the toner image not containing the flat pigment held on the toner image holding member is Ac, a mode is set such that Am> Ac.

  The invention of claim 2 includes a first image forming unit using a toner containing a flat pigment, a second image forming unit using a toner not containing a flat pigment, and a flat pigment formed by the first image forming unit. A fixing unit that fixes a toner image and a toner image that does not include a flat pigment formed in the second image forming unit to a recording medium, and that includes the flat pigment formed in the first image forming unit An image obtained by fixing the gloss of an image fixed on the recording medium by the fixing unit to Bm, and a toner image not including a flat pigment formed by the second image forming unit fixed on the recording medium by the fixing unit When the gloss of Bc is Bc, a mode is set such that Bm <Bc.

  According to a third aspect of the present invention, the first image forming unit and the second image forming unit have a latent image holding body on which a toner image is formed, and the unit image area per unit area of the toner image on the latent image holding body. By controlling the toner mass for each latent image holding member, the number of toner layers is set such that Am> Ac.

  According to a fourth aspect of the present invention, the gloss is set to satisfy Bm <Bc by controlling the toner mass per unit area of the toner image on the recording medium.

  According to a fifth aspect of the present invention, the first image forming unit and the second image forming unit have a developing member that develops a latent image on the latent image holding member and forms a toner image, and is applied to the developing member. The toner mass per unit area of the toner image on the latent image holding member is controlled by controlling the potential of the developing bias.

  According to the first aspect of the present invention, compared to the case of Am ≦ Ac, the flat surface of the flat pigment (flat pigment) can be in an irregular posture with respect to the paper surface of the recording medium.

  According to the second aspect of the present invention, compared with the case of Bm ≧ Bc, the flat surface of the flat pigment (flat pigment) can be set to an irregular posture with respect to the paper surface of the recording medium.

  According to the third aspect of the present invention, the number of toner layers is easily set to satisfy Am> Ac as compared with the case where the toner mass per unit area of the toner image on the latent image holding member is not controlled. Can do.

  According to the fourth aspect of the present invention, it is possible to easily set the gloss to be Bm <Bc as compared with the case where the toner mass per unit area of the toner image on the recording medium is not controlled.

  According to the fifth aspect of the present invention, the toner mass per unit area of the toner image of the latent image holding member can be easily controlled as compared with the case where the potential of the developing bias applied to the developing member is not controlled. .

1 is a schematic diagram illustrating an overall configuration of an image forming apparatus according to an exemplary embodiment. FIG. 2 is a schematic diagram illustrating a configuration of an image forming unit included in an image forming unit according to the present embodiment. FIG. 2 is a schematic diagram illustrating a configuration of a toner image forming unit included in an image forming unit according to the present embodiment. (A) is explanatory drawing for demonstrating the number of toner layers of metal color toner, (B) is explanatory drawing for demonstrating the number of toner layers of other color toner. FIG. 4 is a schematic diagram showing a posture in which the number of layers of the metal color toner is small and the reflection surface of the flat pigment is aligned in a direction along the sheet surface of the sheet member and arranged without overlapping. FIG. 5 is a schematic diagram showing a posture in which the reflective surface of the flat pigment has a large number of layers of the metallic color toner and intersects with the direction along the sheet surface of the sheet member, and the direction of facing is not constant and overlapped. 6 is a graph showing a relationship between a toner mass per unit area of metallic toner and a glitter feeling. 6 is a graph showing a relationship between a toner mass per unit area and a gloss of a metal color toner and another color toner. (A) is a schematic diagram schematically showing a state in which the toner mass per unit area of the metallic toner of the sheet member is small, and (B) is a toner mass per unit area of the metallic toner than (A). FIG. 6C is a schematic diagram schematically showing a large state, and FIG. 8C is a schematic diagram schematically showing a state where the toner mass per unit area of the metallic toner is larger than that in FIG. (A) is a schematic diagram schematically showing a state where the toner mass per unit area of the other color toner of the sheet member is small, and (B) is a toner mass per unit area of the other color toner than (A). FIG. 6C is a schematic diagram schematically showing a large state, and FIG. 8C is a schematic diagram schematically showing a state where the toner mass per unit area of other color toner is larger than in FIG.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. First, the overall configuration and operation of the image forming apparatus will be described, and then the main parts of this embodiment will be described. In the following description, the direction indicated by the arrow H in FIG. 1 is the apparatus height direction, and the apparatus width direction is the direction indicated by the arrow W in FIG. In addition, a direction perpendicular to each of the apparatus height direction and the apparatus width direction (shown by an arrow D as appropriate) is defined as an apparatus depth direction.

[Overall configuration of image forming apparatus]
FIG. 1 is a schematic diagram illustrating an overall configuration of an image forming apparatus 10 according to the present embodiment as viewed from the front side. As shown in this figure, the image forming apparatus 10 includes an image forming unit 12 that forms an image on a sheet member P as an example of a recording medium by an electrophotographic method, a medium conveying unit 50 that conveys the sheet member, The image forming apparatus 10 includes a control unit 70 that controls the above-described units and the power supply unit 80, and a control unit 70 that performs post-processing and the like on the formed sheet member P. The power supply part 80 which supplies electric power to said each part including the part 70 is comprised.

<Configuration of image forming unit>
The image forming unit 12 will be described with reference to FIG. 2 which is a schematic view of the image forming unit 12 as viewed from the front side. The image forming unit 12 includes a photosensitive drum 21, which is an example of a latent image holding member, a charger 22, an exposure device 23, a developing device 24, and a cleaning device 25, and generates a toner image. A toner image forming unit 20 to be formed (see also FIG. 3), a transfer device 30 for transferring an image formed by the toner image forming unit 20 to the sheet member P, and a toner image transferred to the sheet member P to the sheet member P And a fixing device 40 that fixes the toner image.

  A plurality of toner image forming units 20 are provided so as to form a toner image for each color. In this embodiment, the toner image forming unit 20 for a total of six colors, that is, the first special color (V), the second special color (W), yellow (Y), magenta (M), cyan (C), and black (K). Is provided. (V), (W), (Y), (M), (C), and (K) shown in FIG. 1 indicate the colors described above. The transfer device 30 transfers a toner image for six colors to a sheet member P at a transfer nip NT from a transfer belt 31 as an example of a toner image holding member on which toner images for six colors are primarily transferred. It is like that.

  In the present embodiment, the first special color (V) is a metal color for adding metallic luster to the image. On the other hand, the second special color (W) is a user-specific corporate color that is used more frequently than other colors. Each color toner will be described later.

(Photosensitive drum)
As shown in FIGS. 2 and 3, the photosensitive drum 21 is formed in a cylindrical shape and is driven to rotate around its own axis by a driving means (not shown). As an example, a photosensitive layer having a negative charging polarity is formed on the outer peripheral surface of the photosensitive drum 21. Note that an overcoat layer may be formed on the outer peripheral surface of the photosensitive drum 21. The photosensitive drums of the respective colors are arranged in a straight line along the apparatus width direction when viewed from the front.

(Charger)
The charger 22 charges the outer peripheral surface (photosensitive layer) of the photosensitive drum 21 to a negative polarity. In this embodiment, the charger 22 is a corona discharge type (non-contact charging type) scorotron charger.

(Exposure equipment)
The exposure device 23 is configured to form an electrostatic latent image on the outer peripheral surface of the photosensitive drum 21. Specifically, the exposure light L (see FIG. 3) modulated according to the image data received from the image signal processing unit constituting the control unit 70 is applied to the outer peripheral surface of the photosensitive drum 21 charged by the charger 22. It comes to irradiate. An electrostatic latent image is formed on the outer peripheral surface of the photosensitive drum 21 by irradiation of the exposure light L by the exposure device 23. In this embodiment, the exposure device 23 is configured to expose the surface of the photosensitive drum 21 while scanning a light beam emitted from a light source with an optical scanning unit (optical system) including a polygon mirror and an Fθ lens. . In the present embodiment, the exposure device 23 is provided for each color.

(Developer)
The developing device 24 develops the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 21 with the developer G containing toner, thereby forming a toner image on the outer peripheral surface of the photosensitive drum 21. ing. Although not described in detail, the developing device 24 includes at least a container 241 that stores the developer G, and a developing roll 242 that supplies the photosensitive drum 21 while rotating the developer G stored in the container 241. Has been. A toner cartridge 27 for supplying the developer G is connected to the container 241 via a supply path (not shown). The toner cartridges 27 for the respective colors are arranged above the photosensitive drum 21 and the exposure device 23 in the apparatus width direction when viewed from the front, and can be individually replaced.

  A developing bias voltage is applied to the developing roll 242. The developing bias voltage is a voltage applied between the photosensitive drum 21 and the developing roll 242, and a photosensitive drum is caused by a potential difference generated between the developing roll 242 and the photosensitive drum 21 by applying the developing bias voltage. The electrostatic latent image 21 is visualized as a toner image.

(Cleaning device)
The cleaning device 25 includes a blade 251 that scrapes off toner remaining on the surface of the photosensitive drum 21 from the surface of the photosensitive drum 21 after the toner image is transferred to the transfer device 30. Although not shown, the cleaning device 25 further includes a housing that collects toner scraped by the blade 251 (see FIG. 3), and a transport device that transports the toner in the housing to a waste toner box. .

(Transfer device)
The transfer device 30 performs primary transfer by superimposing the toner image of the photosensitive drum 21 of each color on the transfer belt 31, and secondarily transfers the superimposed toner image to the sheet member P (see FIG. 2). ing.

  As shown in FIG. 2, specifically, the transfer belt 31 has an endless shape and is wound around a plurality of rolls 32 to determine the posture. In this embodiment, the transfer belt 31 has a reverse obtuse triangular posture that is long in the apparatus width direction when viewed from the front. Among the plurality of rolls 32, a roll 32D shown in FIG. Of the plurality of rolls 32, the roll 32 </ b> T illustrated in FIG. 2 functions as a tension applying roll that applies tension to the transfer belt 31. Among the plurality of rolls 32, the roll 32 </ b> B illustrated in FIG. 2 functions as a counter roll of the secondary transfer roll 34.

  The transfer belt 31 is in contact with the photosensitive drum 21 of each color from below at the upper side extending in the apparatus width direction with the above-described posture, and the image on each photosensitive drum 21 is transferred to the transfer bias from the primary transfer roll 33. Transfer is performed upon application of a voltage. The transfer belt 31 is in contact with the secondary transfer roll 34 at the top of the lower end forming an obtuse angle to form a transfer nip NT. The transfer belt 31 receives the transfer bias voltage from the secondary transfer roll 34 and receives the transfer The toner image is transferred to the sheet member P that passes through the nip NT.

(Fixing device)
As shown in FIG. 2, the fixing device 40 fixes the toner image on the sheet member to which the toner image has been transferred by the transfer device 30.

  The fixing device 40 fixes the toner image on the sheet member P by heating and pressing the toner image in the fixing nip NF formed by the fixing belt 411 wound around the plurality of rolls 413 and the pressure roll 42. It is supposed to be configured. Note that the roll 413H is a heating roll that is provided with, for example, a heater and rotates by a driving force transmitted from a motor (not shown). As a result, the fixing belt 411 rotates in the arrow R direction.

<Medium transport unit>
The medium conveyance unit 50 includes a medium supply unit 52 that supplies the sheet member P to the image forming unit 12 and a medium discharge unit 54 that discharges the sheet member P on which an image is formed. The medium conveyance unit 50 includes a medium return unit 56 used when images are formed on both surfaces of the sheet member P, and an intermediate conveyance unit 58 that conveys the sheet member P from the transfer device 30 to the fixing device 40. It is configured.

  The medium supply unit 52 supplies the sheet members P one by one to the transfer nip NT of the image forming unit 12 in accordance with the transfer timing. The medium discharge unit 54 discharges the sheet member P on which the toner image is fixed by the fixing device 40 to the outside of the device. When the medium returning unit 56 forms an image on the other side of the sheet member P having the toner image fixed on one side, the medium returning unit 56 reverses the sheet member to the image forming unit 12 (medium supply unit 52). It comes to return.

<Post-processing section>
As shown in FIG. 1, the post-processing unit 60 includes a medium cooling unit 62 that cools the sheet member P on which an image is formed by the image forming unit 12, a correction device 64 that corrects the curvature of the sheet member P, and a sheet member. And an image inspection unit 66 for inspecting an image formed on P. Each unit constituting the post-processing unit 60 is disposed in the medium discharge unit 54 of the medium transport unit 50.

  The medium cooling unit 62, the correction device 64, and the image inspection unit 66 constituting the post-processing unit 60 are arranged in this order from the upstream side in the discharge direction of the sheet member P in the medium discharge unit 54. The post-processing is performed on the sheet member P in the discharging process.

[Image forming operation]
Next, an outline of an image forming process on the sheet member P by the image forming apparatus 10 and a subsequent processing process will be described.

  As illustrated in FIG. 1, the control unit 70 that has received the image formation command operates the toner image forming unit 20, the transfer device 30, and the fixing device 40. As a result, the photosensitive drum 21 and the developing roll 242 are rotated, and the transfer belt 31 is rotated. Further, the pressure roll 42 is rotated and the fixing belt 411 is rotated. Further, in synchronization with these operations, the control unit 70 operates the medium conveyance unit 50 and the like.

  As a result, the photosensitive drums 21 of the respective colors are charged by the charger 22 while being rotated. In addition, the control unit 70 sends the image data that has been subjected to image processing by the image signal processing unit to each exposure device 23. Each exposure device 23 emits each exposure light L according to the image data and exposes each charged photosensitive drum 21. Then, an electrostatic latent image is formed on the outer peripheral surface of each photosensitive drum 21. The electrostatic latent image formed on each photoconductor drum 21 is developed by the developer supplied from the developing device 24. As a result, the photosensitive drum 21 of each color has the first special color (V), the second special color (W), yellow (Y), magenta (M), cyan (C), and black (K). A corresponding color toner image is formed.

  The toner images of the respective colors formed on the photosensitive drums 21 of the respective colors are sequentially transferred to the rotating transfer belt 31 by applying a transfer bias voltage through the primary transfer rolls 33 of the respective colors. As a result, a superimposed toner image in which toner images for six colors are superimposed is formed on the transfer belt 31. This superimposed toner image is conveyed to the transfer nip NT by the rotation of the transfer belt 31. The sheet member P is supplied to the transfer nip NT by the medium supply unit 52 in synchronization with the conveyance of the superimposed toner image. By applying a transfer bias voltage at the transfer nip NT, the superimposed toner image is transferred from the transfer belt 31 to the sheet member P.

  The sheet member P to which the toner image has been transferred is conveyed by the intermediate conveyance unit 58 from the transfer nip NT of the transfer device 30 toward the fixing nip NF of the fixing device 40 while being sucked with negative pressure. The fixing device 40 applies heat and pressure (fixing energy) to the sheet member P that passes through the fixing nip NF. As a result, the toner image transferred to the sheet member P is fixed to the sheet member.

  The sheet member P discharged from the fixing device 40 is processed by the post-processing unit 60 while being conveyed by the medium discharge unit 54 toward the discharge medium receiving unit outside the apparatus. The sheet member P heated in the fixing process is first cooled in the medium cooling unit 62. Next, the curvature of the sheet member P is corrected by the correction device 64. Further, the toner image fixed on the sheet member P is detected by the image inspection unit 66 for the presence or absence of toner density defects, image defects, image position defects, and the like. Then, the sheet member P is discharged to the medium discharge unit 54.

  On the other hand, when an image is formed on a non-image surface on which an image of the sheet member P is not formed (in the case of double-sided printing), the control unit 70 uses the conveyance path of the sheet member P after passing through the image inspection unit 66 as a medium. The discharge unit 54 is switched to the medium return unit 56. As a result, the sheet member P is turned upside down and sent to the medium supply unit 52. An image is formed (fixed) on the back surface of the sheet member in the same process as the image forming process on the front surface. The sheet member P is discharged out of the apparatus by the medium discharge unit 54 through a process similar to the post-processing process after image formation on the surface.

<Main part configuration>
(toner)
Next, the toner of this embodiment will be described.

  As shown in FIG. 4, the metallic toner Gm including the flat pigment 120 used as the first special color (V) (hereinafter referred to as “metallic toner Gm”) has a flat shape with a disk shape as a whole. It is said that. Further, the metal color toner Gm has a structure in which a flaky flat pigment 120, a charge control agent (not shown) and the like are internally added to a binder resin such as a styrene acrylic resin. In FIG. 4A, the metal color toner Gm is schematically illustrated in a rectangular shape so that it can be easily distinguished from other color toner Gc described later.

  In this embodiment, the flat pigment 120 is made of flaky and flat aluminum. Specifically, when the flat pigment 120 is placed on a plane and viewed from the side, the horizontal dimension is a flat shape longer than the vertical dimension. Further, the flat pigment 120 has a pair of reflecting surfaces (flat surfaces) 120A facing upward or downward in the drawing.

  The image formed with the metal color toner Gm is reflected by the reflecting surface 120A of the flat pigment 120, thereby giving the image a glittering feeling.

  As shown in FIG. 4B, the flat pigment 120 (FIG. 4A) is used as the second special color (W), yellow (Y), magenta (M), cyan (C), and black (K). The toner Gc of a color other than the metal color that does not include (referred to below)) (hereinafter referred to as “other color toner Gc”) has an irregular shape called a substantially spherical shape or a potato shape, such as a styrene acrylic resin. This binder resin has a structure in which a pigment other than a flat pigment (not shown), a charge control agent, and the like are internally added. 4B schematically shows a spherical shape in a side view, but actually, it has an irregular shape called a substantially spherical shape or a potato shape as described above (see FIG. 11).

  The other color toner Gc does not need to have an irregular shape called a substantially spherical shape or a potato shape, and may be an irregular shape such as a pulverized toner.

(First main part configuration)
The first main configuration will be described.

  A toner image of the metal color toner Gm is formed on the photosensitive drum 21 of the toner image forming unit 20V of the first special color (V (metal color)). On the other hand, toner image forming units 20W, 20Y, 20M, 20C, and 20K for second special colors (W), yellow (Y), magenta (M), cyan (C), and black (K) other than the first special color. A toner image of the other color toner Gc is formed on each of the photosensitive drums 21W, 21Y, 21M, 21C, and 21K. The toner images on the photosensitive drums 21 for the respective colors are primarily transferred to the transfer belt 31 by the transfer device 30.

Then, as shown in FIG. 4A, the number of toner layers of the toner image of the metallic toner Gm transferred to the transfer belt 31 is Am,
As shown in FIG. 4B, when the number of toner layers of the toner image of the other color toner Gc transferred to the transfer belt 31 is Ac,
The image forming apparatus 10 has a mode that is set so that Am> Ac.

  Note that the toner image on the photosensitive drum 21 depends on the amount of the exposure light L of the exposure device 23 shown in FIG. 3, the potential of the developing bias applied to the developing roll 242 of the developing device 24, the charge amount (charging characteristics) of the toner, and the like. By adjusting the toner mass per unit area, the number of toner layers on the transfer belt 31 is set such that Am> Ac. Note that Am> Ac may be set on the photosensitive drum 21.

  Further, when the image area ratio of the electrostatic latent image on the photosensitive drum 21 is 100%, the number of toner layers is set so that Am> Ac. Further, even if the image area ratio of the electrostatic latent image on the photosensitive drum 21 is 100% or less, as long as the image area ratio of the metal color toner Gm and the other color toner Gc is the same, the toner layer The number is set so that Am> Ac. The image area ratio is the ratio of the area occupied by the toner image.

Further, the number of toner layers Am, Ac per unit area of the toner image when the image area ratio is 100% is
Toner mass per unit area: m
Average mass per toner: mt
Average projected area per toner: S
Then,
Number of toner layers = (m / mt) / (1 / S)
Can be defined in

The average projected area S per toner can be obtained from the area (πr ² ) of the circle when the toner shape approximates a spherical shape or a disk shape and the toner has a central particle diameter 2r. The center particle diameter 2r of the toner can be measured using a charge amount distribution measuring device (E-SPART ANALYZER) manufactured by Hosokawa Micron, a multisizer manufactured by Beckman-Coulter.

  Further, by taking out the transfer belt 31 or the photosensitive drum 21 in a state where the toner image is held and observing it with a microscope, the number of toner layers Am and Ac can be confirmed.

<Effect>
Next, the operation of the first main configuration will be described.

  When an image formation command is received so as to impart a glitter (glitter) to at least a part of the image (in a mode in which a glitter is imparted to at least a part of the image), as shown in FIG. The metal color toner image forming unit 20V (an example of the first image forming unit) is operated.

  Specifically, an electrostatic latent image is formed on the surface of the photoconductor drum 21V corresponding to a portion that imparts a glitter (glitter) to the image. That is, when a glitter feeling is imparted to the entire surface of the image, an electrostatic latent image is formed on the entire surface of the photosensitive drum 21V, and when a glitter feeling is imparted partially, an electrostatic latent image corresponding to that part. Is formed.

  The electrostatic latent image formed on the photosensitive drum 21V is developed with a developer containing metal color toner Gm (see FIG. 5 and the like) supplied from the developing device 24V. As a result, a metallic toner image is formed on the photosensitive drum 21V.

  The metal color toner image is transferred to the rotating transfer belt 31, and the other color toner images are sequentially transferred to the transfer belt 31 after the metal color toner image is transferred to the transfer belt 31. As a result, a superimposed toner image in which toner images for six colors are superimposed is formed on the transfer belt 31. This superimposed toner image is transferred from the transfer belt 31 to the sheet member P at the transfer nip NT.

  The sheet member P to which the toner image has been transferred is conveyed from the transfer nip NT of the transfer device 30 toward the fixing nip NF of the fixing device 40 by the intermediate conveyance unit 58. The fixing device 40 applies heat and pressure to the sheet member P that passes through the fixing nip NF. As a result, the toner image transferred to the sheet member P is fixed to the sheet member P.

  Here, the relationship between the glitter (shininess) of the metal color toner Gm and the number of toner layers will be described. 9 and 10 schematically show the toner image of the metal color toner Gm after being fixed to the sheet member P. FIG. In addition, the binder resin of each toner is actually melted and integrated, but in these drawings, the toner is not integrated for easy understanding. The illustration of the other color toner Gc is also omitted.

  In order to give a glittering feeling and improve the glittering feeling with the metallic toner Gm, it is necessary to lower the regular reflectance and increase the diffuse reflectance.

  Specifically, as shown in FIG. 5, the smaller the number of layers Am of the metal color toner Gm, and the closer the layer, the higher the orientation of the toner, and the reflective surface 120 </ b> A of the flat pigment 120 becomes the surface of the sheet member P. Aligns in the direction along the sheet surface PA, and tends to be aligned without overlapping. In this way, the reflecting surface 120A of the flat pigment 120 is aligned in the direction along the sheet surface PA of the sheet member P, and is arranged without overlapping, so that the direction of the reflected light becomes constant, and the regular reflectance is obtained. Becomes higher, the diffuse reflectance becomes lower, and the glitter feeling becomes worse.

  On the other hand, as shown in FIG. 6, as the number of layers Am of the metal color toner Gm increases, the orientation of the toner decreases, and the reflection surface 120A of the flat pigment 120 is in the direction along the sheet surface PA of the sheet member P. And the direction in which the reflecting surface 120A faces is not constant and tends to be an irregular posture. And, since the reflecting surface 120A of the flat pigment 120 is in an irregular posture in this way, the direction of the reflected light becomes random, the regular reflectance becomes low, the diffuse reflectance becomes high, and the glitter feeling is good. Become.

  In the present embodiment, Am> Ac is set, where Am is the number of toner layers of the toner image of the metallic color toner Gm on the transfer belt 31 and Ac is the number of toner layers of the toner image of the other color toner Gc. Has been. Therefore, compared to the case where Am ≦ Ac, the reflecting surface 120A of the flat pigment 120 shown in FIG. 6 has an irregular posture, so that the direction of the reflected light is random, the regular reflectance is lowered, and the diffuse reflection is reduced. The rate is increased and the glitter is improved.

  Further, if the image area ratios of the electrostatic latent images on the photosensitive drum 21 are the same for the metal color toner Gm and the other color toner Gc, Am> Ac is set. Therefore, compared with the case where Am> Ac is not maintained, it is possible to maintain a state where the diffuse reflectance is high and the glitter feeling is good. In other words, even if the gradation (the density of the image) changes, the change in glitter is suppressed.

FIG. 7 is a graph showing the relationship between the toner mass per unit area of the metallic color toner Gm per unit area on the sheet member P before fixing and the glitter feeling. As described above, the brightness is improved as the toner mass per unit area of the metal color toner Gm increases. And as mentioned above,
Number of toner layers = (m / mt) / (1 / S)
Therefore, as the toner mass m per unit area increases, the number of toner layers Am also increases, and it can be seen that the glitter feeling improves when the number of toner layers Am increases.

  The glitter feeling can be objectively evaluated by, for example, BYK-mac (manufactured by Toyo Seiki Co., Ltd., multi-angle colorimeter).

  Further, the toner mass m per unit area of the toner image on the sheet member P may be measured by any method, but an example of the measuring method will be described below.

  First, a 20 mm × 50 mm solid patch image (image area ratio 100%) is output, and the toner of the unfixed toner image of the solid patch image transferred onto the sheet member P is removed and connected to a suction machine. Aspirate with.

  The sucked toner is captured by a filter, and the mass M of the captured toner is measured.

  Then, the toner mass m per unit area of the toner image of the sheet member P is calculated by dividing the captured toner mass M by the area (20 mm × 50 mm).

(Second part configuration)
The second main configuration will be described. In addition, description of the content which overlaps with a 1st principal part structure is abbreviate | omitted.

The gloss (glossiness) of the image of the metallic toner Gm on the sheet member P fixed by the fixing device 40 is Bm,
When the gloss (glossiness) of the image of the other color toner Bc of the sheet member P fixed by the fixing device 40 is Bc,
The image forming apparatus 10 has a mode that is set so that Bm <Bc.

  The unit area on the photosensitive drum 21 depends on the amount of exposure light L of the exposure device 23 shown in FIG. 3, the potential of the developing bias applied to the developing roller 242 of the developing device 24, the charge amount (charging characteristics) of the toner, and the like. The toner mass per unit area is adjusted, and finally the toner mass m per unit area of the toner image before fixing of the sheet member P is adjusted so that Bm <Bc.

  Further, the toner mass m per unit area of the toner image on the sheet member P can be measured using the measurement method described above. Further, the gloss of the image of the sheet member P can be measured using a gloss measuring machine. In this example, Byk gardner micro-tri-gloss meter-gloss 60 ° was used.

  The gloss (glossiness) is defined by the JIS standard as the glossiness of 100 (%) on the glass surface (refractive index of 1.567 over the entire visible wavelength range). Further, on a glass surface having a refractive index of 1.567, a reflectance of 10% at an incident angle of 60 ° is 100% gloss, and a reflectance of 5% at an incident angle of 20 ° is 100% gloss. ). The unit of gloss (glossiness) is only% or a number according to JIS standards. In principle, the measurement angle, measuring device manufacturer name, and model are clearly specified.

<Effect>
Next, the operation of the second main configuration will be described.

  When an image formation command is received so as to impart glitter to at least part of the image (in a mode in which glitter is imparted to at least part of the image), the metallic toner image shown in FIG. The forming unit 20V (an example of the first image forming unit) is operated.

  Then, the sheet member P to which the toner image is finally transferred is conveyed from the transfer nip NT of the transfer device 30 toward the fixing nip NF of the fixing device 40 by the intermediate conveyance unit 58. The fixing device 40 applies heat and pressure to the sheet member P that passes through the fixing nip NF. As a result, the toner image transferred to the sheet member P is fixed to the sheet member P.

  Here, the glitter and gloss (glossiness) of the metal color toner Gm will be described. 9 and 10 schematically show the toner image of the metal color toner Gm after fixing to the sheet member P and the other color Gc. In addition, the binder resin of each toner is actually melted and integrated, but in these drawings, the toner is not integrated for easy understanding.

  As described above, in order to improve the brightness of the metallic color toner Gm, it is necessary to lower the regular reflectance and increase the diffuse reflectance.

  As shown in FIGS. 9A and 10A, when the toner mass m per unit area of the toner image before fixing on the sheet member P is small, a gap is generated between the toners, and the sheet member P is exposed. To do. Therefore, as shown in FIG. 9, the gloss Bm of the metal color toner Gm and the gloss Bc of the other color toner Gc are both small. Further, as shown in FIG. 9A, since the direction of the reflected light is constant, the glitter feeling is bad.

  In the case of the metallic toner Gm, as shown in FIG. 9B, when the toner mass m per unit area of the toner image on the sheet member P is larger than that in FIG. The reflective surface 120A of the pigment 120 is aligned in a direction along the sheet surface PA of the sheet member P, and is close to a posture in which the reflective surfaces 120A are aligned without overlapping. As a result, the direction of the reflected light is constant, the regular reflectance is increased, the diffuse reflectance is lowered, and the glitter feeling is deteriorated. Further, since the surface becomes smooth, the gloss increases as shown in FIG.

  In the case of the metallic toner Gm, as shown in FIG. 9C, when the toner mass m per unit area of the toner image on the sheet member P is further increased, the reflective surface 120A of the flat pigment 120 of the metallic toner Gm. Is an irregular posture in which the direction crossing the direction along the sheet surface PA of the sheet member P and the direction in which the reflecting surface 120A faces are not constant and overlapped. As a result, the direction of the reflected light is random, the regular reflectance is lowered, the diffuse reflectance is increased, and the glittering feeling is improved. Further, since the surface is not smooth, the gloss Bm is small as shown in FIG.

  In the case of the other color toner Gc, as shown in FIG. 10B, when the toner mass m per unit area of the toner image on the sheet member P increases, the gap is almost filled, but the surface smoothness is improved. As shown in FIG. 8, the gloss Bc is not sufficiently large.

  In the case of the other color toner Gc, as shown in FIG. 10C, when the toner mass m per unit area of the toner image on the sheet member P is further increased, the gap is filled and the surface becomes smooth. Therefore, as shown in FIG. 9, the gloss Bc increases.

As described above, in the case of the metal color toner Gm, the gloss has a peak value with respect to the toner mass m per unit area (in the example of FIG. 8, 40 at 3 g / mm ² ), but in the case of the other color toner Gc. The gloss increases as the toner mass m per unit area increases.

The gloss (glossiness) of the image of the metal color toner Gm of the sheet member P fixed by the fixing device 40 is Bm, and the gloss (glossiness) of the image of the other color toner Gc of the sheet member P fixed by the fixing device 40 is used. When Bc <Bc, that is, when the toner mass m per unit area shown in FIG. 8 is larger than 4 g / mm ^{2, the} glitter is improved (state of FIG. 9C). However, when Bm ≧ Bc, that is, when the toner mass m per unit area shown in FIG. 8 is 4 g / mm ² or less, the glitter feeling is deteriorated (states in FIGS. 9A and 9B).

  Therefore, the image forming conditions (the amount of exposure light L of the exposure device 23, the development applied to the developing roll 242 of the developing device 24) are set so that the gloss (glossiness) of the image after fixing of the sheet member P becomes Bm <Bc. By setting the potential of the bias, the charge amount (charging characteristics) of the toner, and the like, the golden feeling is enhanced.

In the present embodiment, the toner mass m per unit area of the toner image of the sheet member P of the metallic toner Gm is set so as to be in the region S of FIG. 8, that is, the state of FIG. Is set so that the toner mass m is larger than 4 g / mm ² .

  From another viewpoint, the toner mass m of the sheet member P is controlled (image forming conditions are set) so that the gloss (glossiness) of the image of the metal color toner Gm is smaller than a predetermined threshold value. 9C (the reflective surface 120A of the flat pigment 120 of the metal color toner Gm is in an irregular posture with respect to the sheet surface PA of the sheet member P), and the glittering feeling is improved.

Here, the setting of image forming conditions (the amount of exposure light L of the exposure device 23, the potential of the developing bias applied to the developing roll 242 of the developing device 24, the charge amount (charging characteristic) of the toner, etc.) And other color toner Gc may have different settings. Further, the toner mass m per unit area may be different between the metal color toner Gm and the other color toner Gc. For example, the toner mass m per unit area of the metal color toner Gm may be set to 5 g / mm ² and the toner mass m per unit area of the other color toner Gc may be set to 4 g / mm ² .

<Others>
In addition, this invention is not limited to the said embodiment.

  In the first main configuration, the number of toner layers is set to be Am> Ac, and in the second main configuration, the gloss is set to be Bm <Bc. These “toner layer number Am> Ac” and “gross Bm <Bc” may both be established, or only one of them may be established. Also, there is a mode in which none of these are set and an image is formed.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments can be taken within the scope of the present invention. This will be apparent to those skilled in the art. For example, in the description of the above embodiment, the case where each color toner image is transferred to the transfer belt 31 has been described as an example. However, each color toner image may be directly transferred to the sheet member P. The toner images may be collectively transferred to a transfer belt or a sheet member P.

  In the above embodiment, the metallic toner image and the other color toner image are simultaneously fixed on the sheet member P. However, the metallic color toner image is fixed on the sheet member P and the other color toner images are fixed. The fixing to the sheet member P may be performed separately.

  Moreover, the said embodiment is illustrated for description, Comprising: It is not limited to them as this invention, Those skilled in the art will recognize from description of a claim, a specification, and drawing. Modifications, deletions, additions, and combinations are possible without departing from the technical idea of the present invention.

  Furthermore, it cannot be overemphasized that it can implement with a various aspect in the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 20Y Toner image formation part (an example of a 2nd image part)
20M toner image forming unit (an example of a second image unit)
20C toner image forming unit (an example of a second image unit)
20K toner image forming unit (an example of a second image unit)
20W toner image forming unit (an example of a second image unit)
20V toner image forming unit (an example of a first image unit)
21Y Photosensitive drum (an example of a latent image holder)
21M photosensitive drum (an example of a latent image holder)
21C photosensitive drum (an example of a latent image holder)
21K photosensitive drum (an example of a latent image holder)
21W photosensitive drum (an example of a latent image holder)
21V photosensitive drum (an example of a latent image holder)
31 Transfer belt (an example of a toner image carrier)
40 Fixing device (an example of a fixing unit)
120 Flat pigment 242 Developing roll (an example of a developing member)
P sheet member (an example of a recording medium, an example of a toner image carrier)

Claims (5)

A first image forming unit using a toner containing a flat pigment;
A second image forming unit using a toner containing no flat pigment;
A toner image holding body for holding a toner image containing a flat pigment formed in the first image forming unit and a toner image containing no flat pigment formed in the second image forming unit;
Have
Am is the number of toner layers of the toner image containing the flat pigment held on the toner image holding body,
When the number of toner layers of the toner image not containing the flat pigment held on the toner image holding member is Ac,
An image forming apparatus having a mode set so that Am> Ac. A first image forming unit using a toner containing a flat pigment;
A second image forming unit using a toner containing no flat pigment;
A fixing unit that fixes the toner image containing the flat pigment formed in the first image forming unit and the toner image not containing the flat pigment formed in the second image forming unit to a recording medium;
Have
The gloss of the image in which the toner image including the flat pigment formed in the first image forming unit is fixed on the recording medium in the fixing unit is Bm,
When the gloss of the image formed by the second image forming unit and not including the flat pigment is fixed to the recording medium by the fixing unit is Bc,
An image forming apparatus having a mode set to satisfy Bm <Bc. The first image forming unit and the second image forming unit have a latent image holding body on which a toner image is formed,
2. The toner layer according to claim 1, wherein the toner layer number is set to satisfy Am> Ac by controlling the toner mass per unit area of the toner image on the latent image holding body for each latent image holding body. Image forming apparatus.   The image forming apparatus according to claim 2, wherein the gloss is set to satisfy Bm> Bc by controlling a toner mass per unit area of the toner image on the recording medium. The first image forming unit and the second image forming unit have a developing member that develops a latent image of the latent image holding member and forms a toner image,
The image forming apparatus according to claim 3, wherein the toner mass per unit area of the toner image of the latent image holding member is controlled by controlling a potential of a developing bias applied to the developing member.

Images