JP2005062599A - Electrophotographic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic toner which excels in transparency, image quality, low-temperature fixing stability, and grindability at the time of production when an OHP form is printed and which makes possible the practical application of a polyolefin resin having a cyclic structure of high safety based on the environmental problems as well. <P>SOLUTION: The toner is manufactured by stages of intnernally adding a C9-based petroleum resin having a mass average molecular weight (Mw) exceeding 3,000 to a mixture composed of at least a binder resin and a coloring agent, kneading the mixture and subjecting the obtained composition to grinding and classifying. The internal addition of the C9-based petroleum resin having the mass average molecular weight (Mw) exceeding 3,000 makes possible the practical application of the toner using the polyolefin resin which satisfies the transparency, the image quality, the fixing stability, the grindability, and the low-temperature fixibility and is free of the environmental problems. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic toner, and in particular, it has good color developability, transparency when printed on OHP (overhead projector) paper, excellent durability and pulverization, and image quality and fixing in low density printing. The present invention relates to a toner for electrophotography having excellent stability.

  In general, image formation by electrophotography is performed by developing an electrostatic latent image with a toner to make it visible, and transferring the toner image obtained by development onto a sheet and fixing it. The toner used for such image formation is usually produced by pulverizing and classifying a composition obtained by kneading a binder resin and a colorant. In addition, it is widely manufactured by adding inorganic fine particles such as hydrophobic silica after classification for the purpose of internally adding waxes to improve fixability and releasability, and preventing blocking and improving fluidity. Has been done.

  Styrene / acrylic resin, polyester resin, epoxy resin, etc. are used as the binder resin for the toner. From the viewpoint of increasing the color and speed of printed materials in recent years and reducing the burden on the environment, color developability and OHP paper are used. The demand for toner with excellent durability as well as low-temperature fixability, as well as transparency when printed on paper, has increased, and various additions of binder resins with a molecular weight distribution and release agents with low melting points have been studied. Yes. In addition, the use of a grinding aid is also known from the viewpoint of productivity.

  Among the above binder resins, the polyester resin has high durability even when the molecular weight is lowered in order to satisfy the transparency, and since it has a carboxyl group at the end of the resin, it has good pigment dispersibility. It tends to be frequently used for forming. For example, carnauba wax is preferably used as a low melting point release agent.

  However, the combination of polyester resin and carnauba wax has good dispersibility, but over-pulverization tends to occur. As a result, the yield deteriorates due to the increase in fine powder, and the productivity decreases when the amount of pulverization is lowered to improve it. Was invited. In addition, many polyester resins contain bisphenol A, and there are reports that are not preferable from the viewpoint of environmental safety in recent years, and binder resins that replace these are also required.

  Therefore, there is a polyolefin resin having a cyclic structure as one of new resins, and Patent Document 1 describes an invention in which this resin is used as a binder resin for toner. The present invention is characterized by high safety, colorless and transparent, high moisture-proof property, and high recyclability as a characteristic of polyolefin resin having a cyclic structure. Therefore, the polyolefin resin is used and the amount of the polymer resin component is binder resin. By containing less than 50% by mass in the whole, it is possible to provide a color toner having excellent fixability and transparency.

  In addition, in view of the shortcoming that the non-offset temperature range is narrow in the toner of the above-mentioned patent document 1, the patent document 2 has a low molecular resin component in order to widen the non-offset temperature range and obtain sufficient fixing performance for high speed. The invention which adds is described.

  On the other hand, Patent Document 3 exemplifies a polyester resin as a preferred binder resin, and uses an aliphatic hydrocarbon-aromatic hydrocarbon copolymer petroleum resin having 9 or more carbon atoms as the pulverization aid, and pulverization only. In other words, it is effective in improving low-temperature fixing, filming resistance, and image stability.

Moreover, as a grinding aid similar to the above, Patent Document 4 describes a C9 petroleum resin (aromatic hydrocarbon petroleum resin) having a mass average molecular weight of 300 to 3000.
Japanese Patent Laid-Open No. 9-101631 JP 2000-284528 A JP 11-72956 A JP 11-344828 A

  However, the polyolefin resin having the above-mentioned cyclic structure is promising as a binder resin that can take over the advantages of the polyester resin, but there are still problems to be solved in practice with the above-described conventional technology.

  That is, when a polyolefin resin having a cyclic structure is used as a binder resin, a large amount of the polymer resin component is effective for so-called high temperature offset, but it has a low temperature offset tendency and transparency when printed on OHP. Since it is low, when it is output to a projector, it becomes an image without color development and is not suitable for low-temperature fixing.

  In addition, if the polymer resin component is reduced to improve low-temperature fixability and transparency, or if the low-molecular resin component is increased, the melt viscosity at the time of fixing decreases and the high temperature offset phenomenon still occurs. Exists. Therefore, in Patent Documents 1 and 2 described above, although effective in widening the fixing area, the printed matter (toner) is easily peeled off from the OHP due to poor toner binding (adhesiveness) in printing on the OHP. There was a bug.

  The low temperature offset is a phenomenon in which the heat of the fixing member is not sufficiently transmitted to the interface between the toner and the paper, and the toner on the paper is transferred to the fixing member side. The high temperature offset is a phenomenon in which the toner is separated on both sides of the fixing member and the paper by excessively supplying heat to the toner to lower the viscosity of the toner and reducing the cohesive force between the toners.

  On the other hand, according to Patent Documents 3 and 4 described above, it is possible to provide a toner that can achieve both pulverization properties and heat storage stability, and is excellent in low-temperature fixing and offset resistance. In the literature, it has been confirmed that not only the grindability but also low-temperature fixing and filming resistance are effective. However, in Patent Document 3, the image density is lowered in a low density portion such as a halftone. Reduction was seen and it was difficult to reproduce uniform image quality. This defect is caused by the fact that the toner is not transferred to the dot portion to be printed when the print portion is observed with a magnifying glass or the like.

  On the other hand, when using the C9 petroleum resin of the above-mentioned Patent Document 4, there was a tendency to improve the problem of lowering the image density, but in the case where the mass average molecular weight is in the range of 300 to 3000, the low Due to the molecular weight, it was vulnerable to high temperature offsets and there were still problems to be solved. This was remarkable when a polyolefin resin having a cyclic structure was used as the binder resin.

  The present invention has been made under such circumstances, and is suitable for practical use of a polyolefin resin having a highly safe cyclic structure in consideration of environmental problems, with excellent transparency, image quality, fixing stability and pulverization during production. An object of the present invention is to provide a toner for electrophotography.

  In order to solve the above problems, the electrophotographic toner of the present invention is obtained by internally adding and kneading a C9 petroleum resin having a mass average molecular weight (Mw) exceeding 3000 to a mixture of at least a binder resin and a colorant. The composition obtained was pulverized and classified to be produced.

  In the electrophotographic toner of the present invention, the binder resin is preferably a polyolefin resin having a cyclic structure, but can also be applied to a polyester resin or the like.

  In the electrophotographic toner of the present invention, the C9 petroleum resin has a softening point of 130 ° C. to 140 ° C. and 1 to 10 parts by mass with respect to 100 parts by mass of the toner. Carnauba wax is preferably added internally.

  The toner according to the present invention may be internally added with a known charge control agent. Examples of the charge control agent include a quaternary ammonium salt and a salt-forming compound thereof for obtaining a positively chargeable toner, and a metal complex or metal complex of salicylic acid or alkylsalicylic acid for obtaining a negatively chargeable toner. Boron-containing potassium salt compounds and the like are preferable.

  In addition, after the above classification, an external additive of an inorganic oxide such as silica, titania or alumina is added to and mixed with the electrophotographic toner of the present invention as necessary. These inorganic oxides function as a fluidity improver.

  As a method for producing the electrophotographic toner of the present invention, the following general production method can be employed. First, a resin, a colorant, and, if necessary, a charge control agent, wax, and the like are uniformly mixed by a Henschel mixer or the like. Next, this mixture is melt-kneaded using a kneader, an extruder, a roll mill or the like.

  Next, the kneaded material is coarsely pulverized using a hammer mill, a cutter mill or the like, and then finely pulverized using a jet mill, a single mill or the like. Thereafter, the finely pulverized product is classified by a DS (dispersion classifier), a zigzag classifier or the like. The average particle size of the toner obtained by classification is preferably 3 to 18 μm.

  To the classified toner particles, silica or the like is added as necessary and mixed uniformly by a Henschel mixer or the like to produce a toner. Silica may have a surface hydrophobized using silicone oil or the like.

  As described above, according to the present invention, a C9 petroleum resin having a mass average molecular weight (Mw) of more than 3000 is internally added to at least a mixture of a binder resin and a colorant, thereby transparent when printed on OHP. Therefore, it is possible to provide a toner suitable for an image forming apparatus which has excellent properties, image quality, fixing stability, pulverization during production, and satisfactory low-temperature fixing, and can use toners using polyolefin resin without environmental problems.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be shown to describe the present invention more specifically. FIG. 1 schematically shows an internal configuration of a color image forming apparatus (printer apparatus) suitable for image formation using toner manufactured according to the present invention. First, the overall configuration of the color image forming apparatus according to the present invention will be described with reference to FIG.

  The internal configuration of the printer apparatus 1 shown in FIG. 1 includes an image forming unit 2, a duplex printing conveyance unit 3, a paper feeding unit 4, and the like. Here, the image forming unit 2 has a configuration in which four image forming units 5 to 8 are arranged side by side, and magenta (M), cyan (C), and yellow (Y) from the right side to the left side of the drawing. And black (K) in this order. Here, the magenta (M), cyan (C), and yellow (Y) image forming units 5 to 7 are configured to perform color printing by subtractive color mixing, and the black (K) image forming unit 8 is configured to perform monochrome printing. This is a configuration that can be used alone.

  Each of the image forming units 5 to 8 is composed of a drum unit DU and a toner unit (developing device) TU, and has the same configuration except for the toner contained in the developing hopper of the toner unit TU. The toner units TU of the image forming units 5 to 8 respectively store M (magenta), C (cyan), Y (yellow), and black (K) color toners (non-magnetic one-component toner). Each color toner is a toner excellent in fixing stability and transparency produced by the method of the present invention.

  Therefore, the configuration will be described by taking the image forming unit 8 including the developing device of the present invention as an example. The drum unit DU accommodates a photosensitive drum 9, a charger 10a, a cleaner 10e, and the like, and a print head 10b is disposed above the drum unit DU. The toner unit TU is configured such that a developing roller 10c and toner manufactured by the method of the present invention are accommodated in the developing device 44.

  The peripheral surface of the photosensitive drum 9 is made of, for example, an organic photoconductive material. In the vicinity of the peripheral surface of the photosensitive drum 9, a charger 10a, a print head 10b, a developing roller 10c, a transfer device 10d, and a cleaner 10e are provided. They are arranged sequentially. The photosensitive drum 9 is rotated in the direction of the arrow, and first, the peripheral surface of the photosensitive drum 9 is uniformly charged by applying a charge from the charger 10a. Then, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 9 by optical writing based on print information from the print head 10b, and a toner image is formed by development processing by the developing roller 10c. In this way, the toner image formed on the peripheral surface of the photosensitive drum 9 reaches the position of the transfer unit 10d as the photosensitive drum 9 rotates in the direction of the arrow, and directly below the photosensitive drum 9 in the direction of the arrow. The image is transferred to the moving paper.

  On the other hand, the paper is transported by the paper feed cassette 11, the standby roller pair 12, the transport belt 13, the drive roller 14 and the like constituting the paper feed unit 4, and the paper feed cassette 11a is rotated by the rotation of the paper feed roller 11a. The sheet transported from 11 is sent to the standby roller pair 12 and further sent onto the transport belt 13 at a timing coincident with the toner image and reaches each transfer device 10d. Then, the toner image is transferred in each transfer device 10d, and the sheet on which the toner image is transferred moves on the conveyance belt 13 in the direction of the arrow according to the movement of the conveyance belt 13, and a heat fixing process is performed in the fixing unit 15. .

  The above-mentioned paper includes not only the paper carried out from the paper feed cassette 11 but also the paper supplied from the MPF tray 16. In this case, the paper is carried in by the paper feed roller 16a, Printing processing is performed.

  The fixing unit 15 includes a heat roller 15a, a press roller 15b, an oil application roller 15c, and the like. The sheet is transferred to the sheet while the sheet is nipped and conveyed between the heat roller 15a and the press roller 15b. For example, a plurality of color toner images are melted and thermally fixed on a sheet. The oil application roller 15c has a function of applying releasable oil to the peripheral surface of the heat roller 15a and removing toner remaining on the heat roller 15a. In addition, when using the toner manufactured by the method of this invention, the said oil application roller 15c is not necessarily required.

  The paper on which the toner image is fixed by the fixing unit 15 is conveyed upward or leftward on the paper surface via the switching flap 17. The switching flap 17 is normally located at a broken line position, and the sheet is guided to the sheet discharge unit 21 via the sheet discharge roller pair 20.

  On the other hand, the transport unit 3 for double-sided printing is configured to be detachable from the apparatus main body, and is a unit to be mounted when performing double-sided printing with the printer device 1 of this example, and includes a plurality of reverse transport roller pairs 18a to 18a. 18e is disposed. In the case of duplex printing, the sheet is once sent upward by the switching flap 17, and when the trailing edge of the sheet reaches the conveying roller pair 19, for example, the conveyance of the sheet is stopped and the sheet is further conveyed in the reverse direction. . By this control, the sheet is carried into the sheet conveyance path of the duplex printing conveyance unit 3 at the lower position, and the sheet is fed in the reverse direction by the reverse conveyance roller pair 18a to 18e, and reaches the standby roller pair 12 again, as described above. Then, the toner image is sent to the transfer unit at a timing coincident with the toner image, and the toner image is transferred to the back surface of the paper.

  FIG. 2 is an external perspective view of the printer apparatus 1 shown in FIG. The printer apparatus 1 shown in FIG. 1 includes an apparatus main body upper part 22 and an apparatus main body lower part 23, and an operation panel 33 is disposed on the apparatus main body upper part 22, and a printing paper discharge unit 21 is formed on the upper surface. Has been. The operation panel 33 includes a key operation unit 33a provided with a plurality of keys, and a display unit 33b such as a liquid crystal display that performs display based on display information output from a CPU 30 in FIG. Further, the printing paper created by each image forming unit is output to the paper discharge unit 21 by the rotation of the paper discharge roller pair 20 and is sequentially stacked on the paper discharge unit 21.

  The apparatus main body lower portion 23 is provided with a front cover 24 that can be opened and closed on the front surface thereof. The front cover 24 is opened, for example, during jam processing or maintenance.

  FIG. 3 is a circuit block diagram of the printer apparatus 1 having the above configuration. In FIG. 3, the circuit block includes an interface controller (hereinafter referred to as I / F controller) 26, a printer controller 28, a printer printing unit 29, a CPU 30, a ROM 31, an operation panel 33, and an EEPROM 32. The I / F controller 26 converts print data supplied from the host device into bitmap data and develops it in the frame memory 27. In the frame memory 27, a storage area is set for each of magenta (M), cyan (C), yellow (Y), and black (K), and data of each color is developed in the corresponding area.

  The data expanded in the frame memory 27 is output to the printer controller 28 and output to the printer printing unit 29 under the control of the CPU 30. At this time, data of each color of magenta (M), cyan (C), yellow (Y), and black (K) is supplied to the corresponding print head 10b in FIG.

  The ROM 31 stores the system program of this example, and the CPU 30 performs processing according to this system program.

  Next, the basic operation of the printer apparatus 1 described above will be described. First, when the power is turned on and the quality of the paper to be used, the number of sheets, the print mode, and other designations are input as a key input or a signal from a host device to be connected, the paper feed roller 11a is set to one by a drive mechanism (not shown). The sheet rotates and feeds the sheet placed and accommodated in the sheet feeding cassette 11 in the direction of the standby roll pair 12. The standby roll pair 12 temporarily stops the rotation, and waits for the conveyance timing in a state where the leading end of the sheet is brought into contact with the holding portion formed by the pair of rollers.

  Subsequently, the drive roller 14 rotates counterclockwise, and the driven roller 14 'is driven to rotate in the same counterclockwise direction. As a result, the transport belt 13 is circulated and moved counterclockwise as a whole, with the upper circulating portion abutting against the four photosensitive drums 9.

  At the same time, each drum unit DU and toner unit TU are sequentially driven in accordance with the printing timing. The photosensitive drum 9 rotates in the clockwise direction, the charger 10a applies a uniform high negative charge to the circumferential surface of the photosensitive drum 9, and the print head 10b generates an image signal on the circumferential surface of the photosensitive drum 9. Accordingly, exposure is performed to form a low potential portion.

  As a result, an electrostatic latent image composed of a high negative potential portion by the charger 10a and a low negative potential portion by exposure is formed. The developing roller 10c of the developing device 44 transfers toner to the low potential portion of the electrostatic latent image to form a toner image on the circumferential surface of the photosensitive drum 9 (reverse development).

  When the leading edge of the toner image on the peripheral surface of the most upstream photosensitive drum 9 is rotated and conveyed to a point facing the conveying belt 13, the standby is performed so that the print start position of the sheet coincides with the opposite point. The roller pair 12 starts to rotate and feeds the paper to the paper carry-in section. The sheet is attracted to the conveyance belt 13 and conveyed to the first transfer unit formed by the photosensitive drum 9 and the transfer device 10d.

  The transfer device 10 d applies a transfer current output from the transfer bias power source to the sheet via the conveyance belt 13. The M (magenta) toner image on the photosensitive drum 9 is transferred onto the sheet by the transfer current applied from the transfer device. Subsequently, the C (cyan) toner image is transferred at the second transfer portion from the upstream, and the Y (yellow) toner image is transferred at the third transfer portion from the upstream. Then, the K (black) toner image is sequentially transferred at the fourth (ie, the most downstream) transfer portion from the upstream.

  In this way, the sheet onto which the four color toner images have been transferred is separated from the conveying belt 13 and carried into the fixing unit 15. The fixing unit 15 heat-fixes the toner image on the paper. After this image fixing, the paper is discharged onto the upper paper discharge unit 21 with the toner image facing down, for example, by a pair of paper discharge rollers 20.

  The printer apparatus 1 according to the present invention includes a full-color mode in which four image forming units are operated to form a full-color image, and a monochrome mode in which only one image forming unit is operated. The full color mode can also be configured by operating the three image forming units M (magenta), C (cyan), and Y (yellow).

  In the printer apparatus 1 operating as described above, each developing device 44 is configured as follows in order to form a stable toner image on the photosensitive drum 9.

  FIG. 4 is a side sectional view schematically showing the main part of the developing device 44 of the present invention. The developing device 44 shown in the figure is detachable from the printer device 1 and is a toner unit TU that constitutes one image forming unit 8 together with the drum unit DU. The developing device 44 includes a hopper 61, and a developing roller 10 c made of a conductive rubber roller is rotatably held in a lower opening of the hopper 61. The toner 62 is accommodated in the hopper 61 and embedded in the toner 62. And a stirring member 63 that stirs the toner.

  In addition, a supply roller 64 made of a sponge body is disposed in pressure contact with the developing roller 10c at the lowermost portion of the developing device 44. The developing roller 10c is provided with a metal leaf spring doctor blade 65 in pressure contact with the oblique upper right peripheral surface thereof, and a squeeze sheet (conductive regulation sheet) 66 in contact with the lower peripheral surface. Yes. The squeeze sheet 66 is provided with conductive regulation sheet bias means including a bias power supply 71. Sealing members 67 are provided on both sides of the doctor blade 65 to isolate the inside and outside of the opening of the hopper 61 and prevent leakage of the toner 62.

  By the way, the toner 62 in the non-development portion remaining on the peripheral surface of the developing roller 10c after the development on the photosensitive drum 9 is scraped off in the developing device to eliminate the developing memory. The rubbing force of the supply roller 64 varies depending on the adhesion force of the toner 62 to the developing roller 10c. That is, a strong rubbing force is required for a toner having a strong adhesive force, but a low rubbing force is sufficient for a toner having a weak adhesive force. It can be said that the adhesion force of the toner 62 to the developing roller 10 c is substantially determined by the charging ability of the toner 62. That is, the smaller the triboelectric charge amount, the weaker the adhesive force, and therefore it is easier to scrape off from the developing roller 10c.

  However, the triboelectric charge amount of the toner 62 is closely related to the adhesion development (so-called photoconductor fogging) to the non-image portion which occurs at the time of development and becomes a problem. Easy to generate. Therefore, in order not to cause such photoconductor fog, it is necessary to increase the triboelectric charge amount of the toner 62. When the frictional charge amount of the toner 62 is increased, the adhesion force to the developing roller 10c is increased, so that it is necessary to apply a strong rubbing force to the supply roller 64.

  Repeating rotation for a long time with such a strong rubbing force is not preferable because it causes deterioration of development characteristics such as reduction in toner charging ability and fluidity. For example, when the charge amount is reduced, the above-described photosensitive member fog is generated, and when the fluidity is reduced, development loss of halftone printing is generated.

Therefore, in the developing device 44 according to the present invention, first, the developing roller 10c is formed of a cored bar and a cylindrical semiconductive (10 ⁶ Ωcm) urethane rubber surrounding the cored bar. A developing bias of “approximately −250 V” is applied from the bias power source 68. Further, the supply roller 64 is composed of a cored bar and a cylindrical semiconductive (10 ⁶ Ωcm) urethane sponge surrounding the cored bar, and a supply bias of “approximately −500 V” is applied to the cored bar as a bias power source 69. Apply from.

Further, the doctor blade 65 is formed of an elastic metal plate, and a doctor bias of “approximately −500 V” is applied to the doctor blade 65 from the bias power source 69. The squeeze sheet 66 located upstream of the supply roller 64 is composed of a conductive member (10 ³ Ωcm), and a sheet bias voltage in a range from 0 V (0 volt) to the developing bias voltage of the developing roller 10 c is applied thereto. Application is performed by a bias power supply 71.

  When the squeeze sheet 66 is formed of a conductive member and a sheet bias voltage in the range from 0 V to the developing bias voltage of the developing roller 10c is applied thereto, the charge of the toner 62 attached to the developing roller 10c can be reduced. As a result, even with a weak rubbing force by the supply roller 64, it is possible to easily scrape off the toner in the non-development portion that has adhered and returned on the developing roller 10c.

  As described above, the developing device 44 according to the present invention employs a contact developing (roller) system in which the developing roller 10 c made of elastic rubber is pressed against the surface of the photosensitive drum 9. Further, high-speed and high-quality development with a non-magnetic one-component toner is obtained with the above-described apparatus configuration.

  With the color image forming apparatus and the image forming process having the above-described apparatus configuration, it is possible to form an image having excellent image quality and excellent fixability and transparency using the toner manufactured according to the present invention.

  Hereinafter, in the embodiment of the present invention, an example of producing the electrophotographic toner of the present invention will be shown, and the present invention will be described more specifically.

<Example 1>
Binder Resin A (Cyclic Polyolefin Resin “TM” manufactured by Ticona: Mw = 6,500, Mw / Mn = 2) 67.0% by mass, Binder Resin B (Cyclic polyolefin resin “TB-15” manufactured by Ticona) Mw = 140,000, Mw / Mn = 28) 20.0% by mass, colorant (CI Pigment Red 57: 1) 4.0% by mass, fixability improver (C9 petroleum resin “Mitsui Chemicals” FTR-2140 "1.0 part by weight, mold release agent (Carnauba wax No. 1 powder imported from Kato Yoko Co., Ltd.) 7.0% by weight, charge control agent (Saltic acid metal complex" E-84 "manufactured by Orient Chemical Co., Ltd.) 1 0.0 mass% was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), melted and kneaded with a biaxial continuous kneader, then cooled, pulverized and classified with a collision plate pulverizer, and a mass average particle size of about 9 μm. Next, colored fine particles were obtained. 100 parts by weight of colored fine particles, hydrophobic silica (Nippon Aerosil Co., Ltd. Silica "R972") 1 part by weight, were mixed in a Henschel mixer to obtain a magenta toner.

<Example 2>
Binder Resin A (Cyclic Polyolefin Resin “TM” manufactured by Ticona: Mw = 6,500, Mw / Mn = 2) 66.0% by mass, Binder Resin B (Cyclic polyolefin resin “TB-15” manufactured by Ticona) Mw = 140,000, Mw / Mn = 28) 20.0% by mass, colorant (CI Pigment Red 57: 1) 4.0% by mass, fixability improver (C9 petroleum resin “Mitsui Chemicals” FTR-2140 "2.0 parts by mass, mold release agent (Carnauba wax No. 1 powder imported from Kato Yoko Co., Ltd.) 7.0% by mass, charge control agent (Saltic acid metal complex" E-84 "manufactured by Orient Chemical Co., Ltd.) 1 0.0 mass% was mixed with a Henschel mixer (Mitsui Mining Co., Ltd.), melted and kneaded with a biaxial continuous kneader, then cooled, pulverized and classified with a collision plate pulverizer, and a mass average particle size of about 9 μm. Next, colored fine particles were obtained. 100 parts by weight of colored fine particles, hydrophobic silica (Nippon Aerosil Co., Ltd. Silica "R972") 1 part by weight, were mixed in a Henschel mixer to obtain a magenta toner.

<Example 3>
Binder Resin A (Cyclic Polyolefin Resin “TM” manufactured by Ticona: Mw = 6,500, Mw / Mn = 2) 65.0% by mass, Binder Resin B (Cyclic polyolefin resin “TB-15” manufactured by Ticona, Mw = 140,000, Mw / Mn = 28) 18.0% by mass, colorant (CI Pigment Red 57: 1) 4.0% by mass, fixability improver (C9 petroleum resin “Mitsui Chemicals” FTR-2140 "5.0 parts by mass, mold release agent (Carnauba wax No. 1 powder imported from Kato Yoko Co., Ltd.) 7.0% by weight, charge control agent (Saltic acid metal complex" E-84 "manufactured by Orient Chemical Co., Ltd.) 1 0.0 mass% was mixed with a Henschel mixer (Mitsui Mining Co., Ltd.), melted and kneaded with a biaxial continuous kneader, then cooled, pulverized and classified with a collision plate pulverizer, and a mass average particle size of about 9 μm. Next, colored fine particles were obtained. 100 parts by weight of colored fine particles, hydrophobic silica (Nippon Aerosil Co., Ltd. Silica "R972") 1 part by weight, were mixed in a Henschel mixer to obtain a magenta toner.

<Example 4>
Binder Resin A (Cyclic Polyolefin Resin “TM” manufactured by Ticona: Mw = 6,500, Mw / Mn = 2) 60.0% by mass, Binder Resin B (Cyclic polyolefin resin “TB-15” manufactured by Ticona) Mw = 140,000, Mw / Mn = 28) 18.0% by mass, colorant (CI Pigment Red 57: 1) 4.0% by mass, fixability improver (C9 petroleum resin “Mitsui Chemicals” FTR-2140 "10.0 parts by mass, release agent (Carnauba wax No. 1 powder imported from Kato Yoko Co., Ltd.) 7.0% by mass, charge control agent (salicylic acid metal complex" E-84 "manufactured by Orient Chemical Co., Ltd.) 1 0.0 mass% was mixed with a Henschel mixer (Mitsui Mining Co., Ltd.), melted and kneaded with a biaxial continuous kneader, then cooled, pulverized and classified with a collision plate pulverizer, and a mass average particle size of about 9 μm. Next, colored fine particles were obtained. 100 parts by weight of the colored particles, hydrophobic silica (Nippon Aerosil Co., Ltd. Silica "R972") to 1 part by weight, were mixed in a Henschel mixer to obtain a magenta toner.

<Example 5>
Cross-linked polyester resin (softening point 141 ° C., glass transition point 62 ° C.) 37% by mass, non-cross-linked polyester resin (softening point 98 ° C., glass transition point 60 ° C.) 53% by mass, colorant (CI Pigment Red 57: 1 ) 4.0% by mass, fixability improver (1.0 part by mass of C9 petroleum resin “FTR-2140” manufactured by Mitsui Chemicals, Ltd.), release agent (carnauba wax No. 1 powder imported from Kato Yoko Co., Ltd.) 4.0 mass %, 1.0% by mass of a charge control agent (Saltylate metal complex “E-84” manufactured by Orient Chemical Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), and melt-kneaded using a biaxial continuous kneader. Then, the mixture was cooled and pulverized and classified with a collision plate pulverizer to obtain colored fine particles having a mass average particle diameter of about 9 μm, and then 100 parts by mass of the colored fine particles, hydrophobic silica (silica “R972” manufactured by Nippon Aerosil Co., Ltd.) 1 quality The parts were mixed in a Henschel mixer to obtain a magenta toner.

<Example 6>
Cross-linked polyester resin (softening point 141 ° C., glass transition point 62 ° C.) 37% by mass, non-cross-linked polyester resin (softening point 98 ° C., glass transition point 60 ° C.) 52% by mass, colorant (C.I. Pigment Red 57: 1 ) 4.0% by mass, fixability improver (2.0 parts by mass of C9 petroleum resin “FTR-2140” manufactured by Mitsui Chemicals, Inc.), release agent (Carnauba wax No. 1 powder imported from Kato Yoko Co., Ltd.) 4.0 mass %, 1.0% by mass of a charge control agent (Saltylate metal complex “E-84” manufactured by Orient Chemical Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), and melt-kneaded using a biaxial continuous kneader. Then, the mixture was cooled and pulverized and classified by a collision plate pulverizer to obtain colored fine particles having a mass average particle diameter of about 9 μm, and then 100 parts by mass of the colored fine particles, hydrophobic silica (silica “R972” manufactured by Nippon Aerosil Co., Ltd.) 1 quality The parts were mixed in a Henschel mixer to obtain a magenta toner.

<Example 7>
Cross-linked polyester resin (softening point 141 ° C., glass transition point 62 ° C.) 37% by mass, non-cross-linked polyester resin (softening point 98 ° C., glass transition point 60 ° C.) 49% by mass, colorant (CI Pigment Red 57: 1 ) 4.0% by mass, fixability improver (5.0 parts by mass of C9 petroleum resin “FTR-2140” manufactured by Mitsui Chemicals, Inc.), release agent (Carnauba wax No. 1 powder imported from Kato Yoko Co., Ltd.) %, 1.0% by mass of a charge control agent (Saltylate metal complex “E-84” manufactured by Orient Chemical Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), and melt-kneaded using a biaxial continuous kneader. Then, the mixture was cooled and pulverized and classified by a collision plate pulverizer to obtain colored fine particles having a mass average particle diameter of about 9 μm, and then 100 parts by mass of the colored fine particles, hydrophobic silica (silica “R972” manufactured by Nippon Aerosil Co., Ltd.) 1 quality The parts were mixed in a Henschel mixer to obtain a magenta toner.

<Example 8>
Cross-linked polyester resin (softening point 141 ° C., glass transition point 62 ° C.) 37% by mass, non-cross-linked polyester resin (softening point 98 ° C., glass transition point 60 ° C.) 44% by mass, colorant (CI Pigment Red 57: 1 ) 4.0% by mass, fixability improver (C9 petroleum resin “FTR-2140” manufactured by Mitsui Chemicals, 10.0 parts by mass), mold release agent (Yoko Kato's imported Carnauba wax No. 1 powder) 4.0% %, 1.0% by mass of a charge control agent (Saltylate metal complex “E-84” manufactured by Orient Chemical Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), and melt-kneaded using a biaxial continuous kneader. Then, the mixture was cooled and pulverized and classified with a collision plate pulverizer to obtain colored fine particles having a mass average particle diameter of about 9 μm, and then 100 parts by mass of the colored fine particles, hydrophobic silica (silica “R972” manufactured by Nippon Aerosil Co., Ltd.) 1 The amount unit, were mixed in a Henschel mixer to obtain a magenta toner.

<Comparative Example 1>
Binder Resin A (Cyclic Polyolefin Resin “TM” manufactured by Ticona: Mw = 6,500, Mw / Mn = 2) 68.0% by mass, Binder Resin B (Cyclic polyolefin resin “TB-15” manufactured by Ticona) Mw = 140,000, Mw / Mn = 28) 20.0% by mass, colorant (CI Pigment Red 57: 1) 4.0% by mass, mold release agent (imported carnauba wax No. 1 powder by Kato Yoko Co., Ltd.) ) 7.0% by mass and 1.0% by mass of a charge control agent (Orient Chemical Co., salicylic acid metal complex “E-84”) were mixed in a Henschel mixer (Mitsui Mining Co., Ltd.), and a biaxial continuous kneader. Melt kneaded. Thereafter, the mixture was cooled and pulverized and classified by a collision plate pulverizer to obtain colored fine particles having a mass average particle diameter of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica “R972” manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner.

<Comparative example 2>
Binder Resin A (Cyclic Polyolefin Resin “TM” manufactured by Ticona: Mw = 6,500, Mw / Mn = 2) 60.0% by mass, Binder Resin B (Cyclic polyolefin resin “TB-15” manufactured by Ticona) Mw = 140,000, Mw / Mn = 28) 18.0% by mass, colorant (CI Pigment Red 57: 1) 4.0% by mass, fixability improver (C9 petroleum resin “Mitsui Chemicals” FTR-0140 "10.0 parts by mass, release agent (Yoko Kato's imported Carnauba wax No. 1 powder) 7.0% by mass, charge control agent (Orient Chemical Co., Ltd. salicylic acid metal complex" E-84 ") 1 0.0 mass% was mixed with a Henschel mixer (Mitsui Mining Co., Ltd.), melted and kneaded with a biaxial continuous kneader, then cooled, pulverized and classified with a collision plate pulverizer, and a mass average particle size of about 9 μm. Next, colored fine particles were obtained. 100 parts by weight of the colored particles, hydrophobic silica (Nippon Aerosil Co., Ltd. Silica "R972") to 1 part by weight, were mixed in a Henschel mixer to obtain a magenta toner.

<Comparative Example 3>
Cross-linked polyester resin (softening point 141 ° C., glass transition point 62 ° C.) 37% by mass, non-cross-linked polyester resin (softening point 98 ° C., glass transition point 60 ° C.) 54% by mass, colorant (C.I. Pigment Red 57: 1 ) 4.0% by mass, mold release agent (Carnauba wax No. 1 powder imported by Kato Yoko Co., Ltd.) 4.0% by mass, charge control agent (oral chemical company salicylic acid metal complex “E-84”) 1.0 mass % Was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and melt-kneaded with a biaxial continuous kneader. Thereafter, the mixture was cooled and pulverized and classified by a collision plate pulverizer to obtain colored fine particles having a mass average particle diameter of about 9 μm. Next, 100 parts by mass of the colored fine particles and 1 part by mass of hydrophobic silica (silica “R972” manufactured by Nippon Aerosil Co., Ltd.) were mixed with a Henschel mixer to obtain a magenta toner.

<Comparative example 4>
Cross-linked polyester resin (softening point 141 ° C., glass transition point 62 ° C.) 37% by mass, non-cross-linked polyester resin (softening point 98 ° C., glass transition point 60 ° C.) 44% by mass, colorant (CI Pigment Red 57: 1 ) 4.0% by mass, fixability improver (C9 petroleum resin “FTR-0140” manufactured by Mitsui Chemicals Co., Ltd.) 10.0 parts by mass, mold release agent (Carnauba wax No. 1 powder imported from Kato Yoko Co., Ltd.) 4.0 mass %, 1.0% by mass of a charge control agent (Saltylate metal complex “E-84” manufactured by Orient Chemical Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), and melt-kneaded using a biaxial continuous kneader. Then, the mixture was cooled and pulverized and classified with a collision plate pulverizer to obtain colored fine particles having a mass average particle diameter of about 9 μm, and then 100 parts by mass of the colored fine particles, hydrophobic silica (silica “R972” manufactured by Nippon Aerosil Co., Ltd.) 1 The amount unit, were mixed in a Henschel mixer to obtain a magenta toner.

  Next, with respect to the toners obtained in Examples 1 to 8 and Comparative Examples 1 to 4, the following transparency evaluation test, fixability evaluation test, grindability evaluation test, and image quality evaluation test for the low density portion As a result of performing each evaluation based on the results, good results were obtained in Examples 1 to 8.

<Transparency evaluation test>
Each obtained toner sample is quantified and filled in a dedicated toner cartridge, and then the toner unit TU is installed in the printer apparatus 1 (printer manufactured by Casio Computer: Color Page Presto N5: A4 29 sheets / min. Machine) shown in FIG. (In this example, magenta toner is taken as an example, so the toner unit TU of the image forming unit 5) was set.

  Then, the fixing unit 15 of the printer apparatus 1 is modified so that the fixing temperature can be varied, and a solid image is printed using OHP paper (3G company: CG3710) in a normal environment (25 ° C., 50% RH). . In this test, the oil application roller 15c of the fixing unit 15 of the printer apparatus 1 was removed so that a difference in transparency was likely to occur.

  Next, a part of the printed image is cut out, and the maximum transmittance in the wavelength range of 400 nm to 700 nm is measured using a spectrophotometer (manufactured by Shimadzu Corporation: UV-2400PC), and the following evaluation criteria are used. Transparency was evaluated. The process speed was 34.1 mm / sec, and the fixing temperature was 150 ° C.

(Evaluation criteria)
A: The maximum transmittance is 80% or more, which is very good practically.
○: The maximum transmittance is 60% to 80%.
X: The maximum transmittance is less than 60%, which causes a practical problem.

<Fixability (fixing strength) evaluation test>
A tape was affixed to the image printed in the transparency evaluation test, and whether or not the image was peeled off when the tape was peeled off was determined visually, and was used as a fixing strength test. Further, the offset state when the OHP paper passed through the fixing unit 15 of the printer 1 was visually observed.

  As the peeling tape, a scotch mending tape (manufactured by 3M: width 18 mm) was used, and the peeling area was 18 mm × 50 mm. When applying the tape to the image surface, be careful not to let air enter the application area. After applying, rub it with a plastic eraser three times, and then peel off the tape so that the peel angle is 90 ° (vertical). I went. The peeling speed was about 2 seconds / 50 mm.

(Evaluation criteria)
○: No peeling of the image is observed, and there is no offset.
X: Even if a part of image is peeled off, there is a problem in practical use. There is also the occurrence of offset.

<Crushability evaluation test>
In the production methods described in the above Examples and Comparative Examples, when the obtained kneaded crushed material is pulverized and classified with a pulverizer, the toner has a volume average particle size of 9 μm and a number ratio of 3 μm or less as a fine powder is 3. The pulverization conditions were adjusted so that the volume ratio of the coarse powder of 5% or less and 16 μm or more was 1% or less. Further, Multisizer II (aperture size 100 μm) manufactured by Coulter, Inc. was used for the particle size distribution measuring instrument. Then, the yield (mass%) of the particles serving as the toner base was determined as the grindability index. Experience has shown that there is no practical problem if the yield is 70% by mass or more.

<Image quality evaluation test for low-density areas>
Each of the obtained toner samples was quantified and filled in a dedicated toner cartridge in the same manner as described above, and then the toner was added to the printer device 1 (printer device manufactured by Casio Computer: Color Page Presto N5: A4 29 sheets / minute machine). The unit TU was set as a toner unit TU of the image forming unit 5 because magenta toner is taken as an example in this example.

In a normal environment (25 ° C., 50% RH), a low density printing pattern is printed on plain paper (Xerox Corporation: L paper A4 size: mass 64 g / m ² ), and the obtained image is visually observed with a loupe. Observation was made and the evaluation criterion was whether or not there were missing dots. The process speed was 129.3 mm / sec and the fixing temperature was 180 ° C.

(Evaluation criteria)
○: No missing dot.
×: Dot is missing.

  Table 1 summarizes the evaluation results. In Table 1, the cyclic polyolefin resin is abbreviated as COC resin.

  From Table 1, the toners of Examples 1 to 8 have 1 to 10% by mass of the C9 petroleum resin (mass average molecular weight (Mw) exceeding 3000) of the present invention as a fixability improver. , Both show good results in each evaluation item. On the other hand, Comparative Examples 1 and 3 are inferior in fixability, grindability, and image quality because the C9 petroleum resin of the present invention is not internally added. In this case, since the C9 petroleum resin itself has been conventionally known as a grinding aid, it can be easily understood that the grindability is significantly different depending on the presence or absence of this addition. It is worth noting that the influence also affects.

  In Comparative Examples 2 and 4, a C9 petroleum resin having a mass average molecular weight (Mw) of 3000 or less (2760) was internally added instead of the C9 petroleum resin of the present invention. As can be seen from comparison with Examples 4 and 8, there was a problem in the fixing property. Incidentally, physical property values other than the mass average molecular weight (Mw) of the C9 petroleum resin of the present invention used in Examples 1 to 8 and the C9 petroleum resin used in the comparative example were as follows.

  That is, with respect to the softening point of the C9 petroleum resin of the present invention = 137 ° C., the glass transition point = 88 ° C., and the number average molecular weight (Mn) = 1870, the softening point of the C9 petroleum resin used in the comparative example = 138 ° C. Glass transition point = 75 ° C. and number average molecular weight (Mn) = 1510. Therefore, the inventors of the present invention focused on the molecular weight and conducted additional tests on C9 petroleum resins having various molecular weights. As a result, it was found that the difference in the fixing offset occurred when the mass average molecular weight (Mw) was 3000. did.

  The internal addition amount of the C9 petroleum resin of the present invention is no problem when used up to about 20% by mass, but the effect on transparency was confirmed as the addition amount increased. Therefore, it was considered to be preferably about 1 to 10% by mass.

  By the way, Examples 1-4 and Examples 5-8 compare the case where the polyolefin resin having a cyclic structure is used as the binder resin and the case where the polyester resin is used. However, it was proved that a polyolefin resin having a cyclic structure can sufficiently withstand practical use although the polyester resin is excellent. In addition, if problems such as bisphenol A can be overcome, it can be seen that the present invention can also be applied when a polyester resin is used as a binder resin.

  Next, the effect of the colorant and the results of experiments conducted to confirm the effect of the present invention with respect to other colorants necessary for actually forming a color image will be described below as another example. In this alternative embodiment, only the colorant is changed based on the fourth embodiment.

<Another Example 1>
Binder Resin A (Cyclic Polyolefin Resin “TM” manufactured by Ticona: Mw = 6,500, Mw / Mn = 2) 60.0% by mass, Binder Resin B (Cyclic polyolefin resin “TB-15” manufactured by Ticona) Mw = 140,000, Mw / Mn = 28) 18.0% by mass, colorant (CI Pigment Blue 15: 3) 4.0% by mass, fixability improver (C9 petroleum resin “Mitsui Chemicals” FTR-2140 "10.0 parts by mass, release agent (Carnauba wax No. 1 powder imported from Kato Yoko Co., Ltd.) 7.0% by mass, charge control agent (salicylic acid metal complex" E-84 "manufactured by Orient Chemical Co., Ltd.) 1 0.0 mass% was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), melted and kneaded with a biaxial continuous kneader, then cooled, pulverized and classified with a collision plate pulverizer, and a mass average particle size of about 9 μm. Next, colored fine particles were obtained. 100 parts by weight of the colored particles, hydrophobic silica (Nippon Aerosil Co., Ltd. Silica "R972") to 1 part by weight, were mixed in a Henschel mixer to obtain a cyan toner.

<Another Example 2>
Binder Resin A (Cyclic Polyolefin Resin “TM” manufactured by Ticona: Mw = 6,500, Mw / Mn = 2) 60.0% by mass, Binder Resin B (Cyclic polyolefin resin “TB-15” manufactured by Ticona) Mw = 140,000, Mw / Mn = 28) 18.0% by mass, colorant (CI Pigment Yellow 17) 4.0% by mass, fixability improver (C9 petroleum resin “FTR-” manufactured by Mitsui Chemicals, Inc.) 10.0 parts by weight of 2140 ", 7.0% by weight of mold release agent (Carnauba wax No. 1 powder imported by Kato Yoko Co., Ltd.), 1.0% of charge control agent (metal salicylate complex" E-84 "manufactured by Orient Chemical Co., Ltd.) The mass% was mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), melted and kneaded with a biaxial continuous kneader, then cooled, pulverized and classified with a collision plate crusher, and colored with a mass average particle size of about 9 μm. Fine particles were obtained. 100 parts by weight of colored fine particles, hydrophobic silica (Nippon Aerosil Co., Ltd. Silica "R972") 1 part by weight, were mixed in a Henschel mixer to obtain a yellow toner.

<Another Example 3>
Binder Resin A (Cyclic Polyolefin Resin “TM” manufactured by Ticona: Mw = 6,500, Mw / Mn = 2) 60.0% by mass, Binder Resin B (Cyclic polyolefin resin “TB-15” manufactured by Ticona) Mw = 140,000, Mw / Mn = 28) 18.0% by mass, colorant (carbon black) 4.0% by mass, fixability improver (C9 petroleum resin “FTR-2140” manufactured by Mitsui Chemicals, Inc.) 0 parts by mass, 7.0% by mass of release agent (Carnauba wax No. 1 powder imported from Kato Yoko Co., Ltd.), 1.0% by mass of charge control agent (Saltylate metal complex “E-84” manufactured by Orient Chemical Co., Ltd.) Mixing with a mixer (manufactured by Mitsui Mining Co., Ltd.), melt-kneading with a biaxial continuous kneader, then cooling and pulverizing and classifying with a collision plate pulverizer to obtain colored fine particles having a mass average particle diameter of about 9 μm. Then this colored granules 100 parts by weight of hydrophobic silica (Nippon Aerosil Co., Ltd. Silica "R972") to 1 part by weight, were mixed in a Henschel mixer to obtain a black toner.

  Next, as a result of printing on the color toners obtained in the above other Examples 1 to 3 based on the above-described test method, good results were obtained for the above evaluation items. Therefore, finally, the toner of Example 4 and the toners of Other Examples 1 to 3 are used and set as the toner units TU (image forming units 5 to 8) of the printer apparatus 1 in FIG. When 6,000 full-color images were printed, good image output was obtained.

1 is a diagram schematically illustrating an internal configuration of a printer apparatus according to the present invention. 1 is an external perspective view of a printer apparatus according to the present invention. 1 is a circuit block diagram of a printer apparatus according to the present invention. FIG. 2 is a diagram schematically illustrating a main part of a developing device of a printer apparatus according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer apparatus 2 Image formation part 3 Duplex printing conveyance unit 4 Paper feed part 5-8 Image formation unit 9 Photosensitive drum 10a Charger 10b Print head 10c Developing roller 10d Transfer device 10e Cleaner 11 Paper feed cassette 11a Paper feed roller 12 Standby roller pair 13 Conveying belt 14 Drive roller 14 'Driven roller 15 Fixing unit 15a Heat roller 15b Press roller 15c Oil application roller 16 MPF tray 16a Paper feed roller 17 Switching flaps 18a to 18e Reverse conveying roller pair 19 Conveying roller pair 20 Paper discharge Roller pair 21 Paper discharge part 22 Upper part of apparatus main body 23 Lower part of apparatus main body 24 Front cover 26 I / F controller 27 Frame memory 28 Printer controller 29 Printer printing part 30 CPU
31 ROM
32 EEPROM
33 operation panel 33a key operation unit 33b display unit 44 developing device 61 hopper 62 toner 63 stirring member 64 supply roller 65 doctor blade 66 squeeze sheet 67 sealing member 68 bias power source 69 bias power source 71 bias power source

Claims (4)

  It is produced by pulverizing and classifying a composition obtained by internally adding and kneading a C9 petroleum resin having a mass average molecular weight (Mw) exceeding 3000 to a mixture of at least a binder resin and a colorant. An electrophotographic toner.   2. The electrophotographic toner according to claim 1, wherein the binder resin is a polyolefin resin having a cyclic structure.   3. The electrophotographic use according to claim 1, wherein the C9 petroleum resin has a softening point of 130 ° C. to 140 ° C. and is contained in an amount of 1 to 10 parts by mass with respect to 100 parts by mass of the toner. toner.   The electrophotographic toner according to claim 1, 2 or 3, wherein the mixture is further prepared by internally adding carnauba wax.

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