Image forming device

Abstract

To solve the problem in which: in an image forming apparatus of an electrophotographic system using photoluminescent toner for printing, appropriate metallic properties (photoluminescent properties) may not be obtained from some colors of a recording medium.SOLUTION: An image forming apparatus has: image forming units (66, 30, 47) that form photoluminescent toner images on a recording sheet 71; a sheet color determination unit 211 that determines whether the recording sheet 71 is white or colored; and image formation control units (205, 206, 209) that control the image forming units (66, 30, 47). When the sheet color determination unit 211 determines that the recording sheet 71 for printing is colored, the image formation control units (205, 206, 209) increase the amount of formation of the photoluminescent toner images compared with a case where the recording sheet 71 is white.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to an electrophotographic image forming apparatus that uses a photoluminescent toner containing a photoluminescent pigment for printing. [Background technology]

[0002] In conventional image forming apparatuses using glitter toner, the glitter pigment contained in the glitter toner is specified to improve the metallic properties (glitter) during printing (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-84677 A (Page 3, FIG. 8) Summary of the Invention [Problem to be solved by the invention]

[0004] However, simply specifying the glittering pigment may not provide adequate glittering depending on the color of the recording medium. [Means for solving the problem]

[0005] The image forming apparatus according to the present disclosure includes an image forming unit that forms a glossy toner image on a recording medium, According to the FI value of the recording medium, a medium color determination unit that determines whether the recording medium is white or colored, and an image formation control unit that controls the image forming unit; before The image formation control unit is characterized in that, when the medium color determination unit has determined that the recording medium is colored, the amount of the glitter toner image formed is increased compared to when the recording medium is white. Effect of the Invention

[0006] According to the present disclosure, it is possible to obtain good brilliance regardless of whether the recording medium is white or colored. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing a configuration of a main part of a printer as an image forming apparatus according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is an internal configuration diagram showing the internal configuration of the ID unit. [Diagram 3] FIG. 2 is an external perspective view showing the inside of a developer container with a part of an outer casing removed; [Figure 4] 1 is a block diagram showing a configuration of a main part of a printer system according to an embodiment of the present invention, the main part being related to the present disclosure. [Diagram 5] FIG. 13 is a diagram illustrating a method for calculating an FI value. [Figure 6] 1 is a graph showing the print brilliance evaluation value ΔFI values ​​shown in Table 2. [Figure 7] 4 is a graph showing the print brilliance evaluation value ΔFI shown in Table 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Embodiment 1 FIG. 1 is a diagram showing a configuration of a main part of a printer 1 as an image forming apparatus according to a first embodiment of the present disclosure.

[0009] The printer 1 is configured as an intermediate transfer type color electrophotographic printer capable of printing five colors: black (K), yellow (Y), magenta (M), cyan (C), and a special color (S). The special color (S) is a special color that exhibits metallic luster, i.e., has brilliance, such as gold or silver. This special color may be used alone or may be used over a normal color. In the embodiment of the present disclosure, a case in which silver is used as a special color will be described as an example.

[0010] As shown in the figure, the first paper feed cassette 11 contains recording paper 71a as a recording medium stacked inside, and the pickup roller 31 and the paper feed roller pair 12 take out the recording paper 71a one by one from the first paper feed cassette 11 and sequentially send it to the conveying path. On the downstream side of the paper feed roller pair 12 in the direction of the arrow A indicating the conveying direction of the recording paper 71a, there are disposed a conveying roller pair 13 which conveys the recording paper 71a along the path in order, a registration roller pair 14 which corrects skew of the recording paper 71a, and a timing roller pair 15 which sends the recording paper 71a to the secondary transfer unit 47 at a predetermined timing. The first paper feed cassette 11, the pickup roller 31, and the paper feed roller pair 12 constitute a first paper feed unit 10.

[0011] In addition, upstream of the registration roller pair 14, a second paper feed section 35 consisting of a second paper feed cassette 36, a pickup roller 37, and a paper feed roller pair 38 is provided. The second paper feed cassette 36 stores recording paper 71b as a recording medium stacked inside, and the pickup roller 37 and the paper feed roller pair 38 take out the recording paper 71b one by one from the second paper feed cassette 36 and send them sequentially to the registration roller pair 14.

[0012] From the first paper feed section 10 and the second paper feed section 35, either the recording paper 71a or the recording paper 71b is selectively sent to the pair of registration rollers 14. Hereinafter, the recording paper 71a and 71b will be referred to as the recording paper 71 unless there is a need to distinguish between them.

[0013] The developing unit 66 has five image drum units (hereinafter referred to as ID units) 61S, 61C, 61M, 61Y, 61K (simply referred to as 61 when there is no need to distinguish between them) that form developer images of each color, spot color (S), cyan (C), magenta (M), yellow (Y) and black (K), and five LED heads 67S to 67K (simply referred to as 67 when there is no need to distinguish between them).

[0014] The five ID units 61S to 61K are arranged in order from the upstream side along the direction of arrow B, which indicates the direction in which the intermediate transfer belt 44 of the intermediate transfer belt unit 30 described later moves on top of the intermediate transfer belt unit 30, and the five LED heads 67S to 67K are arranged opposite each ID unit 61S to 61K so as to irradiate light onto a specific portion of the photosensitive drum 136 provided in the ID unit 61, as described later.

[0015] 1, the X-axis is the direction in which the intermediate transfer belt 44 moves above the intermediate transfer belt unit 30, the Y-axis is the direction of the rotation axis of the photosensitive drum 136, and the Z-axis is the direction perpendicular to these two axes. Furthermore, when the X-axis, Y-axis, and Z-axis are shown in other figures described later, these axial directions indicate a common direction. That is, the X-axis, Y-axis, and Z-axis in each figure indicate the arrangement direction when the depicted parts of each figure are configured as the printer 1 shown in FIG. 1. Furthermore, here, the Z-axis is arranged to be approximately vertical.

[0016] Since the internal configuration of the ID units 61 is common, the internal configuration will be described using the black (K) ID unit 61K as an example. Figure 2 is an internal configuration diagram showing the internal configuration of the ID unit 61. Note that in Figure 1, only a part of the shape of the developer container 112 (Figure 2) of the ID unit 61S is shown differently.

[0017] As shown in the figure, the ID unit 61 is broadly composed of an image forming main body 111, a developer container 112, a developer supply unit 113, and an LED (Light Emitting Diode) head 67. Incidentally, the ID unit 61 and each of its constituent parts have a sufficient length in the Y-axis direction according to the length of the recording paper 71 in that direction. For this reason, many of the parts have a relatively long length in the Y-axis direction compared to the lengths in the X-axis and Z-axis directions, and are formed in an elongated shape along the Y-axis direction.

[0018] The developer container 112 contains developer therein, and is configured to be detachable from the main body of the ID unit 61. When the developer container 112 is mounted on the main body of the ID unit 61, it is attached to the image forming main body 111 via the developer supply unit 113.

[0019] 3 is an external perspective view showing the inside of the developer container 112, with part of the outer casing removed for this purpose. As shown in the figure, the developer container 112 has a container housing 120 that is long in the Y-axis direction, and a container chamber 121 that is a cylindrical space long in the Y-axis direction is formed inside the container housing 120, and the developer is contained in the container chamber 121. Hereinafter, left and right, front and back, and up and down may be specified when viewed from the direction of arrow B (the negative side in the X-axis direction) shown in FIG. 3.

[0020] A supply hole 122 that connects the space inside the storage chamber 121 to the outside space is drilled in the approximate center of the left and right sides of the bottom of the storage chamber 121, and a shutter 123 is provided for opening and closing the supply hole 122. The shutter 123 is connected to a lever 124, and opens and closes the supply hole 122 in accordance with the rotation of the lever 124. The lever 124 is operated by the user when the developer container 112 is attached to or detached from the ID unit 61.

[0021] For example, before the developer container 112 is attached to the ID unit 61 (FIG. 2), the supply hole 122 is closed in advance by the shutter 123 to prevent the developer contained inside the container chamber 121 from leaking out. When the developer container 112 is attached to the ID unit 61, the lever 124 is rotated in a predetermined opening direction to move the shutter 123 and open the supply hole 122.

[0022] As a result, the developer container 112 communicates the space in the container chamber 121 with the space in the developer supply part 113, and supplies the developer in the container chamber 121 to the image forming main body part 111 via the developer supply part 113. When the developer container 112 is removed from the ID unit 61, the lever 124 is rotated in a predetermined closing direction, thereby moving the shutter 123 to close the supply hole 122.

[0023] Agitating member 125 is provided inside storage chamber 121. Agitating member 125 is formed in a shape such that a long and thin member is wound in a spiral shape around an imaginary central axis along the left-right direction, and is capable of rotating around this imaginary central axis inside storage chamber 121. Agitating drive unit 126 is provided at an end of container housing 120.

[0024] The agitation drive unit 126 is connected to the agitation member 125, and when a driving force is supplied from a predetermined driving force source provided in the housing 2 (FIG. 1), the driving force is transmitted to the agitation member 125 to rotate it. In this way, the developer container 112 agitates the developer contained in the container chamber 121, prevents the developer from coagulating, and sends the developer to the supply hole 122.

[0025] The image forming main body 111 (FIG. 2) incorporates an image forming housing 130, a developer containing space 131, a first supply roller 132, a second supply roller 133, a developing roller 134, a developing blade 135, a photosensitive drum 136, a charging roller 137, and a cleaning blade 138. Of these, the first supply roller 132, the second supply roller 133, the developing roller 134, the photosensitive drum 136, and the charging roller 137 are each configured in a cylindrical shape with their central axes aligned in the left-right direction, and are each rotatably supported by the image forming housing 130.

[0026] Incidentally, in the ID unit 61S for the special color (S), a developer container 112 containing a developer previously selected by the user, in this case the glitter toner described later, is attached to the image forming main body 111 via a developer supply unit 113.

[0027] The developer storage space 131 stores the developer supplied from the developer storage container 112 via the developer supply unit 113. The first supply roller 132 and the second supply roller 133 each have an elastic layer made of a conductive urethane rubber foam or the like formed on their circumferential side. The developing roller 134 has an elastic layer having elasticity and a conductive surface layer or the like formed on their circumferential side. The developing blade 135 is made of, for example, a stainless steel plate of a predetermined thickness, and a part of it is brought into contact with the circumferential side of the developing roller 134 in a state where it is slightly elastically deformed.

[0028] The photosensitive drum 136 has a thin-film charge generating layer and a charge transport layer formed in that order on its peripheral side so that it can be charged. The charging roller 137 has a conductive elastic body coated on its peripheral side, and this peripheral side is brought into contact with the peripheral side of the photosensitive drum 136. The cleaning blade 138 is made of, for example, a thin resin plate, and a part of it is brought into contact with the peripheral side of the photosensitive drum 136 while being slightly elastically deformed.

[0029] The LED head 67 is located above the photoconductor drum 136 in the image forming main body 111. In the LED head 67, a plurality of light-emitting element chips are arranged linearly in the left-right direction, and each light-emitting element is caused to emit light in a light emission pattern based on an image data signal supplied from the image forming control unit 205 (FIG. 4) described later.

[0030] The image forming main body 111 rotates the first supply roller 132, the second supply roller 133, the developing roller 134, and the charging roller 137 in the direction of the arrow (clockwise in the figure) and rotates the photosensitive drum 136 in the direction of the arrow (counterclockwise in the figure) by receiving a driving force from a motor (not shown). Furthermore, the image forming main body 111 applies a predetermined bias voltage supplied from an image forming control unit 205 (FIG. 4) described later to the first supply roller 132, the second supply roller 133, the developing roller 134, the developing blade 135, and the charging roller 137, respectively, to charge them.

[0031] The first supply roller 132 and the second supply roller 133 are charged to cause the developer in the developer containing space 131 to adhere to their circumferential sides, and then rotate to cause this developer to adhere to the circumferential side of the developing roller 134. The developing roller 134 has excess developer removed from the circumferential side by the developing blade 135, and with this developer adhered in a thin film form, the circumferential side is brought into contact with the circumferential side of the photosensitive drum 136.

[0032] Meanwhile, the charging roller 137, in a charged state, comes into contact with the photoconductor drum 136, thereby uniformly charging the circumferential surface of the photoconductor drum 136. The LED head 67 sequentially exposes the photoconductor drum 136 by emitting light at predetermined time intervals in a light emission pattern based on image data signals supplied from the image formation control unit 205 (FIG. 4). As a result, electrostatic latent images are sequentially formed on the circumferential surface of the photoconductor drum 136 near its upper end.

[0033] Next, photoconductor drum 136 rotates in the direction of the arrow, thereby bringing the area where the electrostatic latent image is formed into contact with developing roller 134. As a result, developer adheres to the circumferential surface of photoconductor drum 136 based on the electrostatic latent image, and a developer image based on image data is developed. Photoconductor drum 136 further rotates in the direction of the arrow, thereby causing this developer image to reach the vicinity of the bottom end of photoconductor drum 136.

[0034] 1, an intermediate transfer belt unit 30 is disposed below each ID unit 61 inside the housing 2. The intermediate transfer belt unit 30 includes a drive roller 41 driven by a drive source (not shown), a tension roller 43 that applies tension to the intermediate transfer belt 44, a pair of reverse bending rollers 63, a secondary transfer backup roller 42 that is disposed opposite to a secondary transfer roller 46 and constitutes a secondary transfer section 47, and the intermediate transfer belt 44 that is stretched around these rollers.

[0035] Furthermore, the intermediate transfer belt unit 30 includes five primary transfer rollers 45S to 45K (simply designated by 45 when there is no need to distinguish between them) arranged to face the photosensitive drums 136 of the ID units 61S to 61K. Each of these primary transfer rollers 45 primarily transfers the developer image formed on the photosensitive drum 136 it faces onto the intermediate transfer belt 44.

[0036] As described above, the intermediate transfer belt unit 30 primarily transfers the developer image formed by the developer forming section 66 onto the intermediate transfer belt 44, and then transports the primarily transferred developer image to the secondary transfer section 47. In the secondary transfer section 47, the secondary transfer roller 46 secondarily transfers the developer image primarily transferred onto the intermediate transfer belt 44 onto the recording paper 71 sent out from the timing roller pair 15.

[0037] The fixing device 62 comprises an upper heating roller 62a which is driven to rotate in the direction of the arrow by a drive source not shown, and a lower pressure roller 62b which is in pressure contact with the upper roller 62a and rotates following the rotation. The fixing device 62 clamps the recording paper 71 sent out from the secondary transfer unit 47 in the nip portion and transports it at a predetermined transport speed. During the transport process, heat and pressure are applied to the developer image on the recording paper 71 to melt it, and the melted developer image is fixed to the recording paper 71.

[0038] The first separator 51 is set to a discharge position where it guides the recording paper 71 discharged from the fixing unit 62 and transported by the discharge roller pair 16 to the discharge roller pairs 17-20, and a reprint position where it guides the recording paper 71 to the reprint transport section 32. The discharge roller pairs 17, 18, 19, and 20 discharge the recording paper 71 guided by the first separator 51 to a face-down stacker 72.

[0039] The reprint transport unit 32 includes a second separator 52 that determines the path of the recording paper 71 guided by the first separator 51 set to the reprint position, a forward / reverse roller pair 21 that transports the recording paper 71 back and forth as necessary, a third separator 53 that determines the path of the recording paper 71, a two-pass transport roller pair 22 that transports the recording paper 71 for two-pass printing, a double-sided printing transport roller pair 23 that transports the recording paper 71 for double-sided printing, reprint transport roller pairs 24, 25, and 26 that transport the recording paper 71 sent from these rollers back to the timing roller pair 15, and a retraction unit 27 that temporarily stores the recording paper 71 during double-sided printing. The reprint transport unit 32 may be configured as a unit.

[0040] Each pair of rollers receives power from a conveying drive motor (not shown) via a drive transmission means (not shown), and each separator receives power for setting its rotational position from a solenoid (not shown) via a drive transmission means (not shown).

[0041] In the reprint transport unit 32 configured as above, the transport of the recording paper 71 during two-pass printing will first be described.

[0042] At this time, the recording paper 71 that has been subjected to the first fixing operation by the fixing device 62, i.e., the so-called one-pass printed (first printing), is guided to the two-pass printing path 28 by the second separator 52 set to the introduction position, the third separator 53 set to the two-pass printing position, and the forward / reverse roller pair 21 that transports the paper in the forward direction.

[0043] The recording paper 71 transported to the two-pass printing path 28 is transported in the direction of arrow C by the two-pass transport roller pair 22 and the reprint transport roller pairs 24, 25, and 26, and reaches the timing roller pair 15 again with the surface (front side) printed in the first pass printing as the upper surface (printed surface), and two-pass printing (second printing on the same surface of the same recording paper) is performed. At this time, the first separator 51 is set to the discharge position, and the recording paper 71 on which the two-pass printing has been completed is transported by the discharge roller pairs 16-20, and is eventually discharged to the face-down stacker 72.

[0044] In the above-mentioned two-pass printing, for example, in one-pass printing, color image printing is performed using a color developer image formed by sequentially overlapping developer images formed by ID units 61Y, 61M, 61C, and 61K, and in two-pass printing, special color image printing is performed by printing a clear image formed by ID unit 61S on top of a color image.

[0045] In this embodiment, one-pass printing is described in which the ID unit 61S containing the glitter toner and the other ID units 61Y, 61M, 61C, and 61K perform printing together, but there is no particular limitation and the printing process may also be performed using two-pass printing.

[0046] Next, the transport of the recording paper 71 in the reprint transport section 32 during double-sided printing will be described.

[0047] At this time, the recording paper 71 printed on one side is stored in the evacuation section 27 in order from the leading edge by the second separator 52 set to the introduction position, the third separator 53 set to the double-sided printing position, and the pair of forward / reverse rollers 21 which transport the paper in the forward direction.

[0048] Then, when the trailing end of the recording paper 71 passes through the second separator 52, and for example, the passage of this trailing end is detected by this second separator 52, the forward / reverse roller pair 21, which is still holding the trailing end of the recording paper 71, reverses and rotates in the discharge direction, and the second separator 52 is set to the discharge position.

[0049] As a result, the recording paper 71, most of which has been temporarily stored in the evacuation section 27, is led upside down to the double-sided printing path 29, and is transported in the direction of arrow C by the double-sided printing transport roller pair 23 and the reprint transport roller pairs 24, 25, and 26, until the unprinted side (back side) becomes the upper side (printing side) and reaches the timing roller pair 15 again, where printing on the back side is performed in the same manner as when printing on the front side. At this time, the first separator 51 is set to the discharge position, and the recording paper 71 on which double-sided printing has been completed is transported by the discharge roller pairs 16-20 and eventually discharged to the face-down stacker 72.

[0050] 4 is a block diagram showing the configuration of the main parts of the system of the printer 1 according to the present embodiment that are related to the present disclosure. The following description will be given with reference to FIG.

[0051] As shown in the figure, the printer 1 includes an image generation unit 201 that receives printing information from an external host computer 250 and analyzes the received printing information, an engine control unit 203 that controls engine operation, and an interface unit 202 that receives information necessary for engine control from the image generation unit 201 and communicates with the engine control unit 203.

[0052] The engine control unit 203 is composed of a main control unit 204 that instructs the operation processing for image formation based on information transmitted from the interface unit 202, an image formation control unit 205 that drives and controls the operation for image formation, an image transport control unit 206 that drives and controls the transport of the formed image, a fixing control unit 207 that controls the fixing temperature, etc., a paper transport control unit 208 that monitors the position and drives and controls the transport of the recording paper 71, a secondary transfer control unit 209 that controls the secondary transfer, a printing path control unit 210 that drives and controls the position movement of the first to third separators 51 to 53, and a paper color determination unit 211 that determines the type of color of the recording paper 71.

[0053] An image generating unit 201 receives print information from a host computer 250, generates a print image, and transmits it to an engine control unit 203 via an interface unit 202. A main control unit 204, which also functions as a print speed setting unit, instructs an image formation control unit 205, an image conveyance control unit 206, a fixing control unit 207, a paper conveyance control unit 208, a secondary transfer control unit 209, and a print path control unit 210 on operation processing for image formation, including the print speed.

[0054] The image formation control unit 205 controls the ID unit 61, LED head 67, etc. of the developing and forming unit 66 to form a toner image on the photosensitive drum 136, the image transport control unit 206 controls the intermediate transfer belt unit 30 to transfer the toner image formed by the image formation control unit 205 to the intermediate transfer belt 44 and transport it to the secondary transfer unit 47, and the paper transport control unit 208 controls the transport and speed of the recording paper 71 by all roller pairs and the fixing unit 62.

[0055] The image formation control unit 205 is also configured to be able to change the amount of glitter toner formed by the spot color ID unit 61S. The change in the amount of formation can be achieved by, for example, adjusting the exposure amount of the LED head 67S, the voltage applied to the developing roller 134, the voltage applied to the first and second supply rollers 132, 133, and the voltage applied to the transfer roller 45S. In this embodiment, the amount of glitter toner formed by the spot color ID unit 61S is changed based on a medium color calculation means, as described later.

[0056] When the recording paper 71 conveyed under the control of the paper conveyance control unit 208 and the toner image conveyed under the control of the image conveyance control unit 206 reach the secondary transfer unit 47, the secondary transfer control unit 209 controls the secondary transfer unit 47 to secondarily transfer the toner image onto the recording paper 71. The fixing control unit 207 controls the fixing device 62 to apply heat and pressure to the toner image on the recording paper 71 to melt the toner image and fix the image onto the recording paper 71.

[0057] The developing unit 66, the intermediate transfer belt unit 30, and the secondary transfer unit 47 correspond to an image forming unit, and the image formation control unit 205, the image transport control unit 206, and the secondary transfer control unit 209 correspond to an image formation control unit.

[0058] In addition, since this embodiment is described as an image forming apparatus using an intermediate transfer method, the image forming unit includes intermediate transfer belt unit 30 as part of the image forming unit; however, in the case of an image forming device using a direct transfer method, there is no intermediate transfer belt unit, so the image forming unit that forms a glossy toner image and the transfer unit that transfers the glossy toner image onto paper correspond to the components of the image forming unit.

[0059] The printing path control unit 210 controls the first to third separators 51 to 53 to set a transport path for the recording paper 71 during two-pass printing and double-sided printing, and the paper color determination unit 211, which serves as a medium color determination unit, determines the color of the recording paper 71.

[0060] Here, the paper color determination unit 211 determines the paper color by sensing the user selectively operating a paper color selection button arranged on a printer panel, not shown; however, as a medium color calculation means, a correspondence table of Table 1, in which medium names correspond to FI values ​​(FI0) of recording media, may be stored in a memory unit, not shown, and when a recording medium is selected using a medium type selection button arranged on a printer panel, not shown, the FI value (FI0) of the recording medium may be determined based on the correspondence table of Table 1.

[0061] Furthermore, a paper color measuring unit 11a (see FIG. 1) as a medium color calculation means may be provided in the paper feed cassette 11 to determine the paper color by obtaining an FI value (described later) of the recording paper 71. Furthermore, the paper color of the recording paper 71 to be printed may be determined based on an FI value directly input by the user from the printer panel.

[0062] Next, the manufacture of the glitter toner contained in the developer container 112 of the spot color ID unit 61S for imparting glitter to the printed image will be described.

[0063] First, in the process of obtaining an aqueous medium with an inorganic dispersant dispersed therein, 920 parts by weight of industrial trisodium phosphate dodecahydrate is mixed with 27,000 parts by weight of pure water, and dissolved at a liquid temperature of 60°C. Dilute nitric acid is then added to adjust the pH. An aqueous calcium chloride solution in which 440 parts by weight of industrial calcium chloride anhydride is dissolved in 4,500 parts by weight of pure water is added, and the mixture is stirred at high speed for 34 minutes at 3,566 revolutions per minute in a line mill (PRIMIX Corporation) while maintaining the liquid temperature at 60°C, to prepare an aqueous phase containing a suspension stabilizer (inorganic dispersant).

[0064] On the other hand, in the process of obtaining a pigment dispersion oil-based medium, the pigment dispersion is mixed with 7430 [parts by weight] of ethyl acetate, 680 [parts by weight] of a glittering pigment (volume median diameter 5.4 [μm]), and 30 [parts by weight] of a charge control agent (BONTRON E-84: manufactured by Orient Co., Ltd.). Then, the mixture is heated and stirred to a liquid temperature of 55 [°C], and 260 [parts by weight] of an ester wax (WE-4: manufactured by NOF Corp.) and 2430 [parts by weight] of a polyester resin are added, and the mixture is stirred until no solid matter remains to prepare an oil phase. The oil phase is added to the aqueous phase whose liquid temperature has been lowered to 55 [°C], and suspended by stirring at 1000 [rpm] for 5 minutes to form particles. The ethyl acetate is then removed by vacuum distillation.

[0065] Nitric acid is added to the toner-containing slurry to adjust the pH to 1.6 or less, and the slurry is stirred to dissolve the tricalcium phosphate suspension stabilizer and dehydrated. The dehydrated toner is redispersed in pure water, stirred, and washed with water. The toner is then dehydrated, dried, and classified to produce toner base particles. The toner base particles are collected through the classification process.

[0066] Next, in the external addition process, 1.0 [wt%] small silica (RY200: manufactured by Aerosil Co., Ltd.) and 1.5 [wt%] colloidal silica (X24-9163A: manufactured by Shin-Etsu Chemical Co., Ltd.) were added to the recovered toner base particles and mixed to obtain glossy toner A with a volume median diameter of 12.79 [μm].

[0067] The volume median diameter (Dv50) refers to the particle diameter when the number or mass of particles larger than a certain particle diameter accounts for 50% of the total number or mass of the powder in the particle size distribution of the powder. Here, the measurement was performed using a precision particle size distribution measuring device, Multisizer 3 (manufactured by Beckman Coulter), under the following measurement conditions. Aperture diameter: 100[μm] Electrolyte: Isoton 2 (Beckman Coulter, Inc.) Dispersion liquid: Neogen S-20F (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is dissolved in the electrolyte and the concentration is adjusted to 5%.

[0068] Beckman Coulter's Multisizer 3 is a particle size distribution measurement device that uses the Coulter principle, also known as the pore electrical resistance method, which measures particle volume by passing a constant current through an aperture in an electrolyte solution and measuring the change in the electrical resistance of the aperture as a particle passes through it.

[0069] Here, 10-20 mg of the measurement sample was added to 5 mL of the above dispersion, dispersed for 1 minute with an ultrasonic disperser, then 25 mL of electrolyte was added, dispersed for another 5 minutes with the ultrasonic disperser, and the aggregates were removed by passing through a mesh with a 75 μm mesh to prepare a sample dispersion. The sample dispersion was added to 100 mL of the above electrolyte, and 30,000 particles were measured, and the volume median diameter was calculated from the volume particle size distribution.

[0070] Glittering toner B having a volume median diameter of 13.45 μm was produced as comparative example 1 using a method similar to that of glittering toner A described above, but by changing the glittering pigment to one having a volume median diameter of 8.7 μm.

[0071] Next, a glitter printing test performed on a recording medium of a plurality of colors using glitter toner A and glitter toner B as test samples will be described.

[0072] The test printing machine (C941dn: manufactured by OKI Data Corporation) used for the test printing has the same configuration as the printer 1 shown in Fig. 1 in terms of the essential components required for the print evaluation here, so the test printing will be described with reference to the printer 1 in Fig. 1. Note that the medium used as the recording paper 71 in Fig. 1 will be referred to as the recording medium in the description of the evaluation test here.

[0073] Glitter toner A was stored in developer container 112 of ID unit 61S for spot color (S), and a 100% solid image (also called 100% print image density) was printed on recording media of each color listed below in a state in which the amount of glitter toner image formed on the recording media before fixing by fixing device 62 was adjusted to the amounts shown in Table 2 below. During this printing, the conveying speed of the recording media (i.e., printing speed) was 18 ppm (A4 landscape), and the fixing temperature by fixing device 62 was 160°C.

[0074] During the glitter printing test, the ID units 61 other than the ID unit 61S are not used, so they are removed from the printer 1 body or separated from the intermediate transfer belt 44.

[0075] Similarly, as a comparative example, glossy toner B was stored in the developer container 112 of the ID unit 61S for the special color (S), and a 100% solid image was printed with the amount of glossy toner image formed on the recording medium before fixing by the fixing device 62 adjusted to each amount shown in Table 3 described below.

[0076] The recording media used in the test were: White paper: (OS coated paper W, 127 [g / m 2 ]: Fuji Xerox Co., Ltd.), Black paper: (colored high-quality black, thick, 90 [g / m 2 ]: Manufactured by Hokuetsu Corporation), Blue paper: (Color quality Blue Thick, 90 [g / m 2 ]: Manufactured by Hokuetsu Corporation), Red paper: (Colored high-quality red, thick, 90 [g / m 2 ]: Manufactured by Hokuetsu Corporation It is.

[0077] The glitteriness (metallic luster) of the recording medium before printing and the printed 100% solid image was measured using a goniophotometer (GC-5000L: manufactured by Nippon Denshoku Industries Co., Ltd.). Specifically, as shown in Figure 5, the goniophotometer emitted a light beam C from a direction of 45[°] to the surface of the recording medium, irradiated the recording medium, and received the light in a direction of 0[°] to the vertical direction to measure the brightness index L * 0, and receive light at a direction of 30[°] from the vertical direction and calculate the brightness index L * 30 Then, light is received at a direction of -65° from the vertical direction and the brightness index L * -65 The brilliance of the image was then determined by the flop index value (FI value) calculated by substituting each brightness index into the following formula. FI = 2.69 × (L * 30 -L * -65 ) 1.11 / (L * o ) 0.86

[0078] The increase in glitteriness due to printing was evaluated using the ΔFI value (herein referred to as the print glitteriness evaluation value) obtained by subtracting the FI value (FI0) of the recording medium before printing from the FI value of the solid image. The larger this print glitteriness evaluation value ΔFI value is, the more glitteriness is improved by printing, and when the ΔFI value is 7.0 or more, it is determined that the effect of improving glitteriness by printing is good.

[0079] In addition, in order to compare the FI value (FI0) of the recording medium before printing with the regular reflectance, the regular reflectance (gloss) was measured using a surface gloss meter (Microgloss 75°: manufactured by BYK-Gardner).

[0080] In addition, in order to confirm the difference between FI0 and the regular reflectance of the white recording medium, the regular reflectance (gloss) of the following recording media that were not used in the glitter printing test was also measured and compared. Excellent gloss (128[g / m 2]: Made by Oki Data Corporation), ColorCopy(250[g / m 2 ]: Mondi), Excellent White (80[g / m 2 ]: Made by OKI Data Corporation)

[0081] Table 1 shows the FI value (FI0) and regular reflectance of the recording medium of each color before printing.

[0082] [Table 1]

[0083] As described above, the print brilliance evaluation value ΔFI obtained by printing a 100% solid image on recording media of each color with the amount of image formation of brilliant toner A set in multiple stages is shown in Table 2, and a graph of each of these values ​​is shown in Figure 6.

[0084] [Table 2]

[0085] In addition, the print brilliance evaluation value ΔFI obtained by printing a 100% solid image on recording media of each color with the amount of image formation of brilliance toner B (Comparative Example 1) set to multiple levels is shown in Table 3, and a graph of each of these values ​​is shown in Figure 7.

[0086] [Table 3]

[0087] As shown in Table 1, the white recording medium has a high specular reflectance of 69.8% but a low specular reflectance of 4.4%, a large difference. On the other hand, there is not a large difference in FI0 between white recording media, and it is clear that it depends on the color. Therefore, specular reflectance and FI0 are considered to be completely separate parameters.

[0088] Also, from the test results in Table 1, if FI0 is 7.0 or more, it can be determined that the recording medium is colored, and if FI0 is 5.6 or less, it can be determined that the recording medium is white. Therefore, the paper color determination unit 211 (FIG. 4) determines that the color of the recording paper 71 stored in the paper feed cassette 11 is colored if the FI value of the recording paper 71 input from the printer panel (not shown) as described above, or the FI value obtained from the FI information of the recording paper 71 measured by the paper color measurement unit 11a if the paper feed cassette 11 is provided with the FI value as described above, is 7.0 or more, and determines that the color of the recording paper stored in the paper feed cassette 11 is white if the FI value is 5.6 or less.

[0089] In this embodiment, the recording medium is judged to be white when the FI value is 5.6 or less, and colored when it is 7.0 or more, but the recording medium may be judged to be white or colored by using a predetermined FI value as a boundary. For example, the recording medium may be judged to be white or colored by using 6.3, which is the intermediate value between FI values ​​5.6 and 7.0, as the predetermined FI value.

[0090] As shown in Table 2 and Figure 6, when glitter toner A, which has a glitter pigment with a small particle size, was used, on a white recording medium, the amount of glitter toner image formed was stable in a high range of ΔFI value of 7.0 or more when the amount was below a certain amount, and when the amount was above the certain amount, the ΔFI value tended to decrease as the amount of glitter toner image formed increased.

[0091] On the other hand, for each of the black, blue, and red colored recording media, when the amount of the glossy toner image formed was equal to or greater than a certain amount, the ΔFI value stabilized in a high range of 7.0 or more, and when the amount was below the certain amount, the ΔFI value tended to decrease as the amount of toner decreased.

[0092] When the amount of the glitter toner image formed on the recording medium is small, the gaps between the glitter pigments on the printed surface after fixing are large, and the color of the recording medium is visible through the gaps. Since a white recording medium reflects almost all white light, the glitter is high even if the recording medium is visible through the gaps between the pigments.

[0093] In addition, since the white recording medium has a low FI value of 4.0 before printing, even if the amount of the glossy toner image formed is small, the glossiness appears better than the FI value of the recording medium. On the other hand, as the amount of the glossy toner image formed increases, the amount of the glossy pigment increases, the gaps decrease, and the glossy pigment aggregates, reducing the reflection of the irradiated light, resulting in a decrease in glossiness.

[0094] When white light is irradiated onto each of the recording media of colors black, blue, and red, the light of the recording medium's color is absorbed, resulting in less reflected light. For this reason, when the amount of formed glitter toner image is small and the recording medium can be seen through the gaps in the glitter pigment, the glitter is low. On the other hand, when the amount of formed glitter toner image increases, the pigment aggregates more, but the gaps in the glitter pigment decrease, so the recording medium is no longer able to absorb the white light, resulting in higher glitter. In addition, because the FI value of the recording medium before printing is high, the amount of glitter pigment must be increased in order to achieve a higher glitter than the recording medium.

[0095] The photoluminescent toner B used in the photoluminescent printing test as a comparative example has a larger particle size of the photoluminescent pigment, but the particle size of the toner itself is almost the same as that of photoluminescent toner A. Therefore, the number of photoluminescent pigment particles incorporated in the toner particles is smaller than that of photoluminescent toner A.

[0096] Therefore, even if the amount of the glossy toner image formed on the recording medium is the same as that of glossy toner A, the amount of the glossy pigment on the recording medium will be less than that of glossy toner A. Therefore, as shown in Table 3 and Figure 6, even if the amount of the glossy toner image formed on the recording medium is increased, particularly for blue and red recording media, the recording medium can be seen through the gaps in the glossy pigment, and the glossiness is not improved.

[0097] In this embodiment, the glitter toner A has a glitter pigment with a volume median diameter of 5.4 μm, but it is believed that the same effect can be obtained with a glitter toner with a volume median diameter smaller than 5.4 μm. However, if the volume median diameter is smaller than 5.4 μm, the glitter pigment production yield will be poor and the toner is not suitable for mass production.

[0098] From the above test results, it was found that in order to obtain a good ΔFI value (7.0 or more here) when printing with a glitter toner containing a glitter pigment with an appropriate volume median diameter (5.4 μm here), the amount of glitter toner image formed needs to be a predetermined value (0.36 [mg / cm 2 In the case of colors other than white (here, black, blue, and red), the amount of formed glossy toner image is set to a predetermined value (0.36 [mg / cm 2 ]) or more.

[0099] It can also be seen that there is a tendency for a good ΔFI value to be obtained by increasing the amount of formed glitter toner image when printing on a colored recording medium compared to when printing on a white recording medium.

[0100] Next, a test was conducted to see how the FI value after printing on recording media of each color (white, black, blue, red) changed depending on the printing speed [ppm] (A4 landscape).

[0101] The test conditions were as follows: the density was adjusted to a constant value to adjust the amount of glossy toner image formed; for example, as shown in FIG. 2, the voltage applied to the developing roller 134 was set to -200 V, and the voltage applied to each of the first and second supply rollers 132, 133 was set to -360 V; and 100% solid images were printed on recording media of each color at various printing speeds.

[0102] Incidentally, the printing at this time was performed using the glitter toner A by a test printing machine (C941dn: manufactured by OKI Data Corporation) in the same manner as in the glitter printing test described above.

[0103] The print speeds [ppm] (A4 landscape) at this time were 18, 22, 27, 32, and 40 as shown in Table 4, and the FI value of the recording medium after printing at each print speed was measured. Table 4 shows the test results.

[0104] [Table 4]

[0105] As shown in the table, for white recording media, the slower the printing speed, the higher the FI value after printing. On the other hand, for colored recording media (black, blue, red), the FI value after printing hardly changed even when the printing speed was changed.

[0106] Based on the above test results, in the printer 1 of this embodiment, when the paper color determination unit 211 determines that the recording paper 71 to be printed is colored (other than white), the amount of the glitter toner image formed is set to be greater than when printing on white recording paper 71. Furthermore, when the recording paper is determined to be colored (other than white), the amount of the glitter toner image formed is set to a predetermined value (here, 0.36 [mg / cm 2 When the color is determined to be white, the amount of the glossy toner image formed is set to a predetermined value (here, 0.36 [mg / cm 2 It is also possible to set the length to less than ].

[0107] Furthermore, when the paper color determination unit 211 determines that the recording paper 71 to be printed is white, it is possible to increase (improve) the FI value after printing by slowing down the printing speed. Therefore, in the printer 1 of this embodiment, the printing speed when printing white recording paper 71 is set slower than the printing speed set when printing colored recording paper 71, whose FI value does not change much with changes in printing speed. This increases (improves) the FI value of the white recording paper 71 after printing.

[0108] As described above, according to the printer 1 of the present embodiment 1, when printing using a glitter toner, it is possible to obtain good glitter regardless of whether the recording medium is white or colored.

[0109] In this embodiment, the printer is provided with a medium color determination unit that determines whether the recording medium is colored or white. However, as a modified example, a medium color determination unit may be provided on a printer driver installed on a host device, such as a personal computer, and the medium color may be sent to the printer along with print instructions, and the amount of formed glossy toner image may be changed based on the results of that transmission. Specifically, when the recording medium is a first medium and is colored, the image formation control unit may increase the amount of the glossy toner image formed compared to when the recording medium is a second medium and is white.

[0110] For example, if the medium color transmission result sent to the printer is colored, the amount of formed glossy toner image is about 0.60 [mg / cm2] by the image formation control unit setting the applied voltage to the development roller 134 to -290V and the applied voltage to each of the first and second supply rollers 132, 133 to -450V. On the other hand, if the medium color transmission result is white, the amount of formed glossy toner image is about 0.20 [mg / cm2] by the image formation control unit setting the applied voltage to the development roller 134 to -110V and the applied voltage to each of the first and second supply rollers 132, 133 to -270V.

[0111] As a result, when the recording medium is colored, the image forming control section forms a greater amount of the glittering toner image than when the recording medium is white, so that good glittering properties can be obtained.

[0112] As a further modified example, a server capable of communicating with the printer may be provided, and a medium color determination unit may be provided on the server. When a recording medium is selected using a medium type selection button provided on the printer panel of the printer, the selection result may be transmitted to the server, the medium color of the recording medium may be determined by a medium color determination unit provided on the server, and the determination result may be transmitted to the printer, and the amount of formation of the glossy toner image may be changed based on the transmission result. [Industrial Applicability]

[0113] In the above embodiment, the present disclosure has been described using a color electrophotographic printer as an example, but the present disclosure is not limited thereto and can be used in image forming apparatuses such as copying machines, facsimiles, MFPs, etc. that form images on recording materials using an electrophotographic method. Also, although the present disclosure has been described with respect to a color printer, it may be a monochrome printer. [Explanation of symbols]

[0114] 1 printer, 2 housing, 3 control unit, 10 first paper feed unit, 11 paper feed cassette, 11a paper color measurement unit, 12 paper feed roller pair, 13 transport roller pair, 14 registration roller pair, 15 timing roller pair, 16 discharge roller pair, 17 discharge roller pair, 18 discharge roller pair, 19 discharge roller pair, 20 discharge roller pair, 21 forward / reverse roller pair, 22 two-pass transport roller, 23 duplex printing transport roller pair, 24 reprint transport roller pair, 25 reprint transport roller pair, 26 reprint transport roller pair, 27 evacuation unit, 28 two-pass printing path, 29 duplex printing path, 30 intermediate transfer belt unit, 31 pickup roller, 32 reprint transport unit, 35 second paper feed unit, 36 Second paper feed cassette, 37 Pickup roller, 38 Paper feed roller pair, 41 Drive roller, 42 Secondary transfer backup roller, 43 Tension roller, 44 Intermediate transfer belt, 45 Primary transfer roller, 46 Secondary transfer roller, 47 Secondary transfer section, 51 First separator, 52 Second separator, 53 Third separator, 61 ID unit, 62 Fixing unit, 62a Upper roller, 62b Lower roller, 63 Reverse bending roller pair, 66 Development forming section, 67 LED head, 71 Recording paper, 72 Face down stacker, 111 Image forming main body, 112 Developer container, 113 Developer supply section, 120 Container housing, 121 Storage chamber, 122 Supply hole, 123 Shutter, 124 Lever, 125 agitation member, 126 agitation drive unit, 130 image forming housing, 131 developer storage space, 132 first supply roller, 133 second supply roller, 134 developing roller, 135 developing blade, 136 photosensitive drum, 137 charging roller, 138 cleaning blade, 201 image generating unit, 202 interface unit, 203 engine control unit, 204 main control unit, 205 image forming control unit, 206 image transport control unit, 207 fixing control unit, 208 paper transport control unit, 209 secondary transfer control unit, 210 printing path control unit, 211 paper color determination unit, 250 host computer.

Claims

1. an image forming section for forming a glossy toner image on a recording medium; a medium color determination unit that determines whether the recording medium is white or colored based on the FI value of the recording medium; an image forming control unit that controls the image forming unit; having When the medium color determination unit determines that the recording medium is colored, the image formation control unit increases the amount of the glitter toner image formed compared to when the recording medium is white.

1. An image forming apparatus comprising:

2. An image forming unit that forms a glossy toner image on a recording medium; a medium color determination unit that determines whether the recording medium is white or colored; an image forming control unit that controls the image forming unit; having the image forming control unit increases the amount of the glitter toner image formed when the medium color determination unit determines that the recording medium is colored, compared to when the recording medium is white; When the medium color determination unit determines that the FI value of the recording medium is 7.0 or more, the image formation control unit increases the amount of formation of the glitter toner image to a predetermined value or more.

1. An image forming apparatus comprising:

3. An image forming unit that forms a glossy toner image on a recording medium; a medium color determination unit that determines whether the recording medium is white or colored; an image forming control unit that controls the image forming unit; having the image forming control unit increases the amount of the glitter toner image formed when the medium color determination unit determines that the recording medium is colored, compared to when the recording medium is white; When the medium color determination unit determines that the FI value of the recording medium is 5.6 or less, the amount of the glitter toner image formed is set to less than a predetermined value.

1. An image forming apparatus comprising:

4. The FI value is obtained by a medium color calculation unit provided in the image forming apparatus.

4. The image forming apparatus according to claim 1, wherein the image forming apparatus further comprises: a first fixing member;

5. The volume median diameter of the glittering pigment contained in the glittering toner image is 5.4 μm or less.

5. The image forming apparatus according to claim 1, wherein the image forming apparatus further comprises a first fixing unit.

6. A printing speed setting unit is provided, and when the medium color determination unit determines that the color of the recording medium is white, the printing speed setting unit sets the printing speed slower than when the medium color determination unit determines that the color of the recording medium is colored.

6. The image forming apparatus according to claim 1, wherein the image forming apparatus further comprises a first fixing unit.

7. An image forming unit that forms a glossy toner image on a recording medium; a medium color determination unit that determines whether the recording medium is white or colored; an image forming control unit that controls the image forming unit; Print speed setting section having the image forming control unit increases the amount of the glitter toner image formed when the medium color determination unit determines that the recording medium is colored, compared to when the recording medium is white; When the medium color determination unit determines that the color of the recording medium is white, the print speed setting unit sets the print speed to be slower than when the medium color determination unit determines that the color of the recording medium is colored.

1. An image forming apparatus comprising:

8. an image forming section for forming a glossy toner image on a recording medium; an image forming control unit that controls the image forming unit; having When the recording medium is a first medium having a first FI value, the image forming control unit The amount of the glitter toner image formed is increased compared to when the recording medium is a second medium having an FI value smaller than the first FI value.

1. An image forming apparatus comprising:

Images