JP4817626B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that removes toner on an intermediate transfer member having a loss tangent within a predetermined range with a blade member.

  In recent years, color image forming apparatuses using an electrophotographic system are also required to support various recording media. For this reason, a color image forming apparatus using an intermediate transfer member capable of dealing with various recording media is widely used.

  Conventionally, as the intermediate transfer member, a single layer structure of polyimide resin has been widely used.

  However, when the toner image carried on the image carrier is transferred to an intermediate transfer member having a single layer structure of polyimide resin, so-called scattering occurs in which the outline of the toner image on the intermediate transfer member is blurred. When the toner image on the image carrier is transferred, the intermediate transfer belt contacts the image carrier. At this time, in the contour portion of the toner image on the image carrier, a gap is generated between the intermediate transfer member and the image carrier due to the thickness of the toner image, and scattering occurs due to this gap.

  Therefore, an intermediate transfer member using an elastic material such as rubber has been used.

  The intermediate transfer member using the elastic material is quickly deformed according to the thickness of the toner image. In the contour portion of the toner image on the image carrier, no gap is generated between the intermediate transfer member and the image carrier. In this way, the occurrence of scattering is suppressed.

  Here, the loss tangent (tan δ) is the amount of force that is absorbed when the material is deformed based on the time until the material deforms after the force is applied and returns to the original shape. It is an indicator to show.

  Thus, the larger the loss tangent (tan δ), the longer the time required for deformation after the force is applied to the substance. Conversely, the smaller the loss tangent (tan δ), the shorter the time from when the force is applied until the material is deformed. Further, the applied force is difficult to be absorbed.

  By the way, as a means for removing the toner remaining on the intermediate transfer member after the toner image on the intermediate transfer member is transferred to the recording medium, since the configuration is simple, there is a wide range of blade members whose edges are in contact with the intermediate transfer member. It is used.

JP 2000-062993 A

  However, when the blade member is used as a means for removing the toner remaining on the intermediate transfer member using an elastic material such as rubber, a so-called cleaning failure in which the remaining toner is not removed occurs.

  Therefore, an object of the present invention is to provide an image that can suppress the occurrence of defective cleaning when the toner remaining on an image carrier such as an intermediate transfer member using an elastic material such as rubber is removed by a blade member. It is to provide a forming apparatus.

In order to achieve the above object, the present invention provides an intermediate transfer member having an elastic layer, transfer means for transferring the toner image carried on the intermediate transfer member to a recording medium, and an edge in contact with the intermediate transfer member. And a blade member that removes toner remaining on the intermediate transfer member from the intermediate transfer member after the toner image is transferred to the recording medium, and includes a surface that contacts the blade member from the intermediate transfer member. The loss tangent tan δ1 of the first test piece cut and molded in this way is 0.05 ≦ tan δ1 ≦ 0.40, and includes the edge contacting the intermediate transfer member and the two surfaces forming the edge. in the image forming apparatus loss tangent Tanderuta2 the second test piece is molded by cutting a portion of the blade member is 0.15 ≦ tanδ2 ≦ 0.40, the said blade member Serial line pressure to the intermediate transfer member N (g / cm) is 20 <a configuration in which the blade member is arranged so as to satisfy N <60, the loss tangent of the blade member and the loss tangent tanδ1 of the intermediate transfer body The loss tangent of each of the intermediate transfer member and the blade member is set so that δ2 satisfies 0.25 ≦ tan δ1 + tan δ2 ≦ 0.65. Further, an elastic layer, and a transfer belt for carrying the recording material, a transfer unit that transfers the toner image to the recording material borne on the transfer belt, the edge comes into contact with the transfer belt, remaining on the transfer belt the toner and a blade member to be removed from the transfer belt, the loss tangent tanδ1 of the first test piece is molded cut to include a surface in contact with the blade member from the transfer belt, 0.05 ≦ tan δ1 ≦ 0.40, and the loss tangent tan δ2 of the second test piece formed by cutting out a part of the blade member so as to include the edge contacting the transfer belt and the two surfaces forming the edge is in the image forming apparatus is 0.15 ≦ tanδ2 ≦ 0.40, a linear pressure N (g / cm) with respect to the transfer belt of the blade member is less than a 20 <N <60 A configuration in which the blade member is arranged so as, the transfer loss tangent of the loss tangent Tanderuta1 and the blade member of the belt δ2 is, to satisfy 0.25 ≦ tanδ1 + tanδ2 ≦ 0.65, wherein said transfer belt The loss tangent of each blade member is set .

According to the present invention, the loss tangent tan δ1 of the image carrier and the loss tangent tan δ2 of the blade member are:
0.25 ≦ tan1 + tan δ2 ≦ 0.65
Therefore, it is possible to suppress the occurrence of poor cleaning when the residual toner on the image carrier such as an intermediate transfer member using an elastic material is removed by the blade member.

  By the way, in order for the blade member to remove the toner on the intermediate transfer member, the blade member and the intermediate transfer member are in stable contact with each other, and there is no gap between the blade member and the intermediate transfer member. is necessary.

  However, when an intermediate transfer member using an elastic material is used, the intermediate transfer member is deformed together with the blade at the contact portion between the blade member and the intermediate transfer member. The deformed intermediate transfer member and blade member return to their original shapes. As a result, the intermediate transfer member and the blade member vibrate, and a gap is generated between the blade member and the intermediate transfer member.

  Further, the surface of the intermediate transfer member has unevenness, and if the blade member corresponds to the unevenness and does not deform quickly, a gap is generated between the blade member and the intermediate transfer member, and similarly a cleaning failure occurs.

  In this way, a clean defect occurs.

  On the other hand, when an intermediate transfer member having a single layer structure of polyimide resin is used, the intermediate transfer member is not deformed at the contact portion between the blade member and the intermediate transfer member. Therefore, when using an intermediate transfer member having a single polyimide resin layer structure, vibration of the intermediate transfer belt is less likely to occur and cleaning defects are less likely to occur than when an intermediate transfer member using an elastic material is used.

  Therefore, in the present invention, the loss tangent between the blade member and the intermediate transfer belt is set as described above to prevent the occurrence of cleaning failure when the residual toner of the intermediate transfer member using the elastic material is removed by the blade member. .

  That is, by setting the sum of the loss tangent tan δ1 of the intermediate transfer member and the loss tangent tan δ2 of the blade member to 0.65 or less, the blade member and the intermediate transfer member are quickly deformed according to the unevenness of the intermediate transfer member, There is no gap between the blade member and the intermediate transfer member, and no cleaning failure occurs.

  Further, by setting the sum of the loss tangent tan δ1 of the intermediate transfer member and the loss tangent tan δ2 of the blade member to be 0.25 or more, vibration generated at the contact portion between the intermediate transfer member and the blade member is caused by the intermediate transfer member and the blade member. Absorbed. At this time, the blade member is in firm contact with the intermediate transfer member, so that no gap is generated, and the occurrence of defective cleaning is suppressed.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  In addition, in each drawing, what attached | subjected the same code | symbol has the same structure or effect | action, The duplication description about these shall be abbreviate | omitted suitably.

<Embodiment 1>
FIG. 1 is a schematic sectional view of an image forming apparatus according to the present invention.
(Image forming device)
The image forming apparatus shown in FIG. 1 is a copier that employs an electrophotographic system, and forms a full-color image on a recording medium in accordance with an image signal sent from a computer (not shown).

  That is, in the image forming apparatus according to the present embodiment, the photosensitive member 1 is uniformly charged by the charging unit 2, and the photosensitive member 1 is irradiated with light from the laser oscillator 7 according to the image signal. Then, an electrostatic latent image is formed on the portion of the photoreceptor 1 irradiated with the light beam, and this electrostatic latent image is developed with toner as a developer in the developing means 8 to be visualized as a toner image. Is done.

  By the way, an elastic intermediate transfer member 4 is wound around three rollers 13, 14, and 15 below the photosensitive member 1, and the intermediate transfer member 4 is a primary transfer roller 12. Is pressed against the photoconductor 1. The toner image visualized on the photosensitive member 1 is transferred onto the intermediate transfer member 4 by applying a transfer voltage to the primary transfer roller 12.

  On the other hand, in the developing means 8, the developing rotary 16 is provided with four developing devices 8a, 8b, 8c, and 8d. These developing devices 8a, 8b, 8c, and 8d include yellow, magenta, cyan, and black. Each toner is accommodated.

  Thus, the electrostatic latent image formed on the photoreceptor 1 is developed with the first color yellow toner by the developing unit 8a facing the photoreceptor 1 as shown in FIG. 1 to form a yellow toner image. The yellow toner image is transferred onto the intermediate transfer body 4 by the action of the primary transfer roller 12 as described above. Thereafter, the developing rotary 16 rotates to change the color to be developed, and the next developing unit 8b develops the electrostatic latent image on the photosensitive member 1 with the second color magenta toner, and the magenta toner image becomes the intermediate transfer member 4. It is transferred on top of it.

  Similarly, when a cyan toner image developed by the developing device 8c and a black toner image developed by the developing device 8d are sequentially transferred onto the intermediate transfer body 4, the full color is transferred onto the intermediate transfer body 4. A toner image is carried.

  As described above, when the four color toner images are transferred onto the intermediate transfer body 4 in a superimposed manner, the sheet S as a recording medium is fed from the paper feed cassette 30 to the portion of the secondary transfer roller 10 and is subjected to the secondary transfer. The toner images for four colors are collectively transferred onto the sheet S by the action of the roller 10. The toner image transferred onto the sheet S is fixed on the sheet S by applying heat and pressure by the fixing unit 18, and a full color image is formed on the sheet S as a permanent image. Thereafter, the toner remaining on the photosensitive member 1 and the intermediate transfer member 4 is removed by the photosensitive member cleaning blade 61 of the photosensitive member cleaning device 6 and the intermediate transfer member cleaning device 17, respectively. The intermediate transfer body 4 is again used for image formation.

  By the way, in this embodiment, an OPC photoreceptor coated as a charge generation layer using a titanyl phthalocyanine pigment and a charge transport layer using a bisphenol Z-type polycarbonate as a binder is used as the photoreceptor 1. Alternatively, a Se photoconductor may be used.

  In the present embodiment, the toner includes a polymerized toner containing an ester wax in the core, styrene-butyl acrylate in the resin layer, and styrene polyester produced by suspension polymerization in the surface layer, and a polymerization method. The mixture with the resin magnetic carrier produced by the above was used as a two-component developer.

Next, the intermediate transfer member cleaning device (hereinafter simply referred to as “cleaning device”) 17 according to the present invention will be described.
(Cleaning device)
FIG. 2 is a side sectional view of the cleaning device 17. As shown in FIG. 2, the cleaning device 17 includes a casing 20 having an opening on the intermediate transfer body 4 side. A cleaning blade 19 as a blade member is attached by a support member 22. Here, the edge 191 of one side of the cleaning blade 19 is in contact with the intermediate transfer body 4, and the residual toner that cannot be completely transferred onto the sheet S by the secondary transfer roller 10 reaches the edge 191 of the cleaning blade 19. Then, the residual toner is scraped off from the intermediate transfer body 4 by the edge 191 of the cleaning blade 19. Details of the cleaning blade 19 will be described later.

  A rake sheet 21 is attached to the lower part of the casing 20. The rake sheet 21 causes the toner scraped off from the intermediate transfer body 4 by the cleaning blade 19 to fall into the casing 20 and is scraped off. It functions to prevent a large amount of toner from flowing back to the intermediate transfer body 4.

  Although not shown, a conveying means for discharging residual toner is disposed in the casing 20, and the residual toner that has dropped into the casing 20 is conveyed by the conveying means in the direction perpendicular to the paper surface of FIG. It is discharged from the device 17. For this reason, the inside of the casing 20 is not clogged with residual toner.

  Here, as the contact condition of the cleaning blade 19 with respect to the intermediate transfer body 4, the contact pressure of the cleaning blade 19 with respect to the surface of the intermediate transfer body 4 is 20 <N <60, preferably 20 (N / g) in terms of linear pressure N (g / cm). It is desirable that 25 ≦ N ≦ 55.

  Incidentally, when the linear pressure N of the cleaning blade 19 is 20 g / cm or less, the transfer residual toner (untransferred toner) remaining on the surface of the intermediate transfer body 4 cannot be sufficiently removed, and the toner slips through. In addition, toner fusing and filming are likely to occur on the surface of the intermediate transfer member 4.

  On the other hand, when the linear pressure N of the cleaning blade 19 is 60 g / cm or more, the cleaning performance of the toner remaining on the intermediate transfer member 4 is improved, but the surface of the outermost layer of the intermediate transfer member 4 is worn heavily. The life of the intermediate transfer body 4 is reduced.

  The linear pressure N that is the contact pressure of the cleaning blade 19 with respect to the intermediate transfer body 4 refers to the total pressure of the cleaning blade 19 with respect to the intermediate transfer body 4 per unit length of the cleaning blade 19. When measuring this total pressure, a load converter is attached to the intermediate transfer body 4 to be measured, the cleaning blade 19 is pressed against the surface of the intermediate transfer body 4, and the load can be measured as the total pressure.

  In the cleaning blade 19 in this embodiment, a portion of the thermosetting polyester polyurethane resin blade 100 (see FIG. 3) as a base that is in contact with the intermediate transfer body 4 and a portion in the vicinity thereof are treated with 4,4-diphenylmethane isocyanate ( MDI) was used to cure a part of the base material to obtain a cured layer.

  The hardness of the base material of the cleaning blade 19 in the present embodiment is 50 to 80 ° (Hs), preferably 65 to 77 °, and the rebound resilience is 10 to 50%, preferably 30 to 40%. The plate thickness is 0.5 to 4.0 mm, preferably 1.0 to 3.0 mm. The contact angle (θ in FIG. 2) of the cleaning blade 19 with respect to the intermediate transfer member 4 is 15 to 35 °, preferably 20 to 25 °, and the free length is 2 to 12 mm, preferably 5 to 10 mm. It is. These values may be appropriately adjusted within a range where the contact pressure of the cleaning blade 19 with respect to the intermediate transfer body 4 is 20 <N <60 (g / cm) as the linear pressure N. The hardness (Hs) of the base material of the cleaning blade 19 conforms to JIS K 6253, and the rebound resilience of the base material of the cleaning blade 19 conforms to JIS K 6255.

  The cleaning blade 19 used in the present embodiment was manufactured by the following method.

  That is, a prepolymer having a weight average molecular weight of 2,000 ethylene butylene adipate-based polyester polyol and 4,4-diphenylmethane diisocyanate having an NCO% of 7.0%, and 1,4-butanediol and trimethylolpropane in a mass ratio. A crosslinker containing a triethylenediamine catalyst mixed in a ratio of 65:35 is mixed so that the molar ratio of hydroxyl group / isocyanate group is 0.9, and a thermosetting polyester system having an international rubber hardness (IRHD) of 70 °. A blade 100 made of polyurethane resin was produced.

  The obtained polyurethane resin blade 100 is left to dry in a vacuum for 60 minutes to remove moisture in the blade 100. Next, as shown in FIG. 3, after immersing the blade 100 in a 4,4-diphenylmethane isocyanate (MDI) bath 102 at 80 ° C. for 5 mm for 3 minutes, the polyurethane resin blade 100 is pulled up from the MDI bath 102 to remove the excess. The MDI was wiped off, and a cleaning blade 19 was produced.

  When the cross section of the intermediate transfer member contact portion of the obtained cleaning blade 19 was observed with an optical microscope, the cured layer was observed as a cloudy layer, and the thickness T of the cured layer was 0.7 mm.

  Next, a method for manufacturing the intermediate transfer member 4 used in this embodiment will be described below.

  FIG. 4 shows a cross section of the intermediate transfer member 4 of the present embodiment. The intermediate transfer body 4 has an endless belt shape, and has a two-layer structure including an outermost layer 41 on which a toner image is carried and a base layer 42 in contact with the primary transfer roller 12. The outermost layer 41 is mainly composed of a resin, and the base layer 42 is composed of an elastomeric material.

  As the main material used for the outermost layer 41, resins, elastomers, or a blend of both can be used, but is not limited thereto. The main binder polymer can be used as a single component or a blend, and the physical properties may be adjusted by adding a plasticizer or the like.

  A specific main material is preferably a polyester-based resin, particularly a polyester polyurethane resin in which polyester contains a certain amount of urethane.

  In the actual intermediate transfer body 4, it is necessary to adjust the electric resistance for controlling the transfer current for each of the outermost layer 41 and the base layer 42, but it is preferable to use a conductive filler as a resistance adjusting method.

  As the type of conductive filler, any conductive filler can be used as long as it is normally used. In particular, carbon fillers such as furnace black, acetylene black, ketjen black, graphite, and carbon fiber, and tin oxide are used. Metal oxide-based conductive fillers typified by zinc oxide impurity-doped products are preferred.

The volume resistivity of the outermost layer 41 is preferably in the range of 10 ⁷ to 10 ¹⁶ Ω · cm. When the volume resistivity is smaller than this range, an excessive transfer current flows. Conversely, when the volume resistivity is large, a sufficient current cannot be obtained, so that a good transfer cannot be performed.

  The film thickness of the outermost layer 41 is specifically 20 μm to 300 μm, more preferably 40 μm to 200 μm, and particularly preferably 80 μm to 150 μm. For example, if the film thickness is 300 μm or more, the resistance of the outermost layer 41 increases, making it difficult to adjust the overall resistance of the intermediate transfer member 4. On the other hand, when the film thickness is 20 μm or less, the outermost layer 41 cannot secure the strength as a film.

  As a method for forming the outermost layer 41, a method in which the raw material of the outermost layer 41 is made into a paint and cured after forming is adopted. In addition to a method of forming the outermost layer 41 by spraying or dipping after forming the base layer 42, separately. A method of bonding the formed layers with an adhesive or the like is used. Furthermore, a method in which the outermost layer 41 is formed in advance by a centrifugal molding method and then the base layer 42 is formed by the same method is preferable for the following reason.

  That is, since both the outermost layer 41 and the base layer 42 are continuously produced by the same equipment, the equipment burden is light and the number of man-hours for transfer between apparatuses can be reduced. Further, since the liquid base layer 42 is introduced after the outermost layer 41 is formed, an appropriate combination of materials does not require an adhesive or the like, and the thickness accuracy is easily obtained.

  Examples of the material used for the base layer 42 include styrene-butadiene rubber, high styrene rubber, butadiene rubber, isoprene rubber, ethylene-propylene copolymer, nitrile butadiene rubber, chloroprene rubber, butyl rubber, silicone rubber, fluorine rubber, and nitrile rubber. , Urethane rubber, acrylic rubber, epichlorohydrin rubber, norbornene rubber and the like.

  Examples of the method for forming the base layer 42 include extrusion molding and centrifugal molding. The thickness of the base layer 42 is preferably in the range of 0.5 mm to 2 mm.

Next, a method for producing the intermediate transfer member 4 will be described.
(Preparation of intermediate transfer member)
The outermost layer 41 of the intermediate transfer member 4 is obtained by dissolving 100 parts by weight of polyester polyurethane in a solvent (methyl ethyl ketone) so that the binder polymer concentration is 20 wt%, and conducting titanium oxide (trade name: FT-3000, Ishihara Techno Co., Ltd.) ) Made by adding 10 parts by weight and dispersing for 30 minutes with a paint shaker, followed by dry molding with a centrifugal molding machine.

  The base layer 42 was produced as follows.

  That is, 100 parts by weight of polyester elastomer (Hytrel 3046, manufactured by Toray DuPont Co., Ltd.) is heated to 180 ° C., and conductive carbon (trade name: Ketjen Black 600JD, manufactured by Ketjen Black International Co., Ltd.) 10 After adding 60 parts by weight of MDI-based isocyanate heated to 180 ° C. and dispersing with a stirrer for 3 minutes, after forming the outermost layer 41, continue to the centrifugal molding machine. It was charged and cured by heating. Thereafter, aging was performed at 80 ° C. for 1 hour, followed by natural cooling to room temperature, taking out from the molding machine, and cutting the end portion to obtain an intermediate transfer body 4. The film thickness of the outermost layer 41 of the obtained intermediate transfer body 4 was 0.14 mm, and the film thickness of the base layer 41 was 1.86 mm.

  The loss tangent of the intermediate transfer member 4 was measured using a viscoelasticity measuring device RSA2 (manufactured by Rheometrics). When the loss tangent at 30 ° C. at 10 Hz was tan δ1, tan δ1 was 0.25.

  As described above, when tan δ1 of the intermediate transfer member 4 is low, the amount of vibration energy absorbed by the intermediate transfer member 4 is reduced, and the energy of the behavior of the cleaning blade 19 can be absorbed by the intermediate transfer member 4. Accordingly, the vibration of the cleaning blade 19 becomes excessive. In such a case, the cleaning blade 19 and the intermediate transfer body 4 may be excessively separated from each other, and at that time, a cleaning failure occurs.

  On the other hand, when tan δ1 of the intermediate transfer body 4 is large, it takes time until the intermediate transfer body 4 itself deforms depending on the unevenness of the surface of the intermediate transfer body 4, and between the cleaning blade 19 and the intermediate transfer body 4. A gap is generated in the substrate, resulting in poor cleaning.

  The tan δ1 of the intermediate transfer member 4 has been described above. Next, the loss tangent of the cleaning blade 19 is assumed to be tan δ2, and the energy absorption amount of the behavior of the cleaning blade 19 is controlled by adjusting the tan δ2. .

  Even when the tan δ1 of the intermediate transfer body 4 is low and the vibration of the cleaning blade 19 tends to be excessive, if the tan δ2 of the cleaning blade 19, particularly the tan δ2 of the cleaning blade 19 near the contact portion is increased, the vibration of the cleaning blade 19 is increased. The amount of energy absorption is increased, and an appropriate behavior can be achieved.

  On the other hand, even if the tan δ1 of the intermediate transfer body 4 is large and the vibration of the cleaning blade 19 tends to be small, if the tan δ2 of the cleaning blade 19, particularly the tan δ2 of the cleaning blade 19 near the contact portion is small, the cleaning blade 19 The amount of vibration energy absorbed becomes small, and an appropriate behavior can be achieved.

  This will be described in more detail below.

The amount of vibration of the intermediate transfer member 4 at the blade contact position∝the vibration energy absorption rate of the intermediate transfer member 4∝tan δ1 of the intermediate transfer member 4
The vibration amount at the drum contact position of the cleaning blade 19 ∝ the vibration energy absorption rate at the cleaning blade 19 ｔ tan δ2 of the cleaning blade 19 in the vicinity of the contact portion
This holds from the definition of loss tangent.

  On the other hand, the amount of vibration at the contact portion between the intermediate transfer body 4 and the cleaning blade 19 is intermediate transfer unless the period of vibration between the intermediate transfer body 4 and the cleaning blade 19 is completely matched and the phase is completely reversed. This is proportional to the sum of the vibration amount at the blade contact position of the body 4 and the vibration amount at the drum contact position of the cleaning blade 19.

  Therefore, the amount of vibration at the contact portion between the intermediate transfer body 4 and the cleaning blade 19 tan δ1 of the intermediate transfer body 4 + tan δ2 of the cleaning blade 19 near the contact portion is established.

  The intermediate transfer member 4 and the cleaning blade 19 of the present embodiment optimize the loss tangent in consideration of these.

  In the following, as a comparative example, the cleaning blade 19 and the intermediate transfer member 4 are variously changed, and the loss tangent tan δ2 of the cleaning blade 19, the loss tangent tan δ1 of the intermediate transfer member 4, and the transfer from the photosensitive member 1 to the intermediate transfer member 4 are performed. The presence or absence of splattering and poor cleaning was verified.

  The loss tangent tan δ2 of the cleaning blade 19 was measured as follows.

  As shown in FIG. 5, measurement is performed using a test piece 200 formed by cutting a part of the cleaning blade 19. The test piece is 200, at least an edge 191 in contact with the intermediate transfer body 4, two surfaces 192 and 193 forming the edge 191, a surface parallel to the surface 192, a surface parallel to the surface 193, and the four surfaces (surface 192). , The surface parallel to the surface 192, the surface 193, and the surface parallel to the surface 193).

  The length a2 in the direction parallel to the edge 191 is 10 mm. The lengths b2 and c2 in the direction perpendicular to the edge 191 on the two surfaces 192 and 193 constituting the edge 191 are each 2 mm.

  Here, b2 and c2 are set to 2 mm because when the cleaning blade 19 removes the toner on the intermediate transfer body 4, the edge 191 and the two surfaces 192 and 193 forming the edge 191 vibrate, and b2 It is because it became clear by examination of this inventor that c2 and c2 are vibrating in the range of 2 mm.

  As shown in FIG. 6, when the lengths b2 and c2 of the two surfaces 192 and 193 constituting the edge 191 in the direction perpendicular to the edge 191 are less than 2 mm, the edges on the surfaces 192 and 193 of the cleaning blade 19 itself. The length in the direction perpendicular to 191 is assumed.

  The cleaning blade 19 shown in FIG. 6 has a length in the direction perpendicular to the edge 191 on the surface 192 of 1 mm. In the test piece 200 of the cleaning blade 19 in FIG. 6, a2 = 10 mm, b2 = 1 mm, and c2 = 2 mm.

  Further, when the shape of the cleaning blade 19 is a shape obtained by cutting out a part of a rectangular parallelepiped as shown in FIG. 7, the direction perpendicular to the edge 191 on the two surfaces 192 and 193 constituting the edge 191 is also shown. It is assumed that each is cut into a width of 2 mm.

  The loss tangent tan δ2 is measured using a viscoelasticity measuring device RSA2 (manufactured by Rheometrics).

  The temperature of the test piece is kept at 30 ° C., a vibration of 10 Hz is applied in a direction parallel to the edge portion, and the loss tangent tan δ2 is measured.

  As a test condition, the frequency of vibration to be applied is 10 Hz. This is the frequency of vibration of the intermediate transfer body 4 and the cleaning blade 19 at the contact portion between the intermediate transfer body 4 and the cleaning blade 19 when the image forming apparatus is used. It is almost equivalent. Since this value is determined by various conditions of the intermediate transfer body 4 and the cleaning blade 19, it is desirable to change appropriately according to them. However, in the experiment of the present inventor, about 10 Hz was appropriate in almost any case, so the experiment was performed with the frequency fixed at 10 Hz.

  Further, it is necessary to pay attention to the loss tangent of the operating temperature in the vicinity of the intermediate transfer member 4 and the cleaning blade 19 in the image forming apparatus. Since this was in the vicinity of approximately 30 ° C., the experiment was conducted while keeping the test piece at 30 ° C. in the present invention. The atmospheric temperature at the time of measurement was set to 30 ° C., and the test piece was measured in a state of being the same as the atmospheric temperature.

  However, ideally, it is desirable to change the temperature of interest according to the usage environment or the like.

  Next, a method for measuring the loss tangent tan δ1 of the intermediate transfer member 4 will be described.

  As shown in FIG. 8, the loss tangent tan δ1 of the intermediate transfer member 4 is measured by using a test piece 210 formed by cutting out a part of the intermediate transfer member 4. The test piece 210 includes at least a surface X in contact with the cleaning blade 19, a surface Y perpendicular to the surface X in contact with the photosensitive member 1, a surface parallel to the surface X, a surface parallel to the surface Y, and the four surfaces (photosensitive members). 1 surface 2 in contact with the photosensitive member 1, a surface Y perpendicular to the surface X in contact with the photoreceptor 1, a surface parallel to the surface X, and a surface parallel to the surface Y). FIG. 8 shows a test piece 210 cut out from the intermediate transfer member 4.

  The length a1 of the rotation direction (in the direction of arrow B in FIG. 8) of the intermediate transfer member 4 on the surface X in contact with the photoreceptor 1 is 2 mm, and the length a1 is perpendicular to the rotation direction of the intermediate transfer member 4 on the surface X in contact with the photoreceptor 1. The length b1 is 10 mm. The length c1 in the direction perpendicular to the surface X in contact with the photoconductor in the surface Y perpendicular to the surface X in contact with the photoconductor 1 is 2 mm.

  Here, the reason why the surface in contact with the cleaning blade 19 is included in the test piece 210 is that the surface in contact with the cleaning blade 19 of the intermediate transfer body 4 vibrates when the cleaning blade 19 removes the toner of the intermediate transfer body 4. It is. Further, the dimensions of the test piece 210 are adjusted to the test piece 200 of the cleaning blade 19 for convenience of measurement.

  As shown in FIG. 9, when the length c1 in the direction perpendicular to the surface in contact with the image carrier in the surface Y perpendicular to the surface in contact with the photoconductor 1 is less than 2 mm, the length c1 of the intermediate transfer body 4 itself. Is the length c1 of the test piece 210.

  In the intermediate transfer member 4 shown in FIG. 9, the length c1 is 1 mm. Therefore, in the test piece 210, a1 = 2 mm, b1 = 10 mm, and c1 = 1 mm.

  Similarly to the loss tangent tan δ2, the loss tangent tan δ1 is also measured using the viscoelasticity measuring device RSA2 (manufactured by Rheometrics).

  Similarly, the temperature of the test piece is kept at 30 ° C., a vibration of 10 Hz is applied in a direction parallel to the edge portion, and the loss tangent tan δ1 is measured.

  As the measurement conditions, the frequency of vibration to be applied is 10 Hz, and the temperature of the test piece 210 is 30 ° C., as in the case of tan δ2.

  As the intermediate transfer member 4, five types of polyester elastomer materials for the base layer were used as shown in Table 1, and other conditions were set in the same manner as described above. Each tan δ is also shown in Table 1. In Table 1, No. 3 is the said form. In Table 1, “O” does not occur (good), and “X” means occurrence (defect) (hereinafter, the same applies to Tables 2 and 3).

  Table 1 shows the loss tangent tan δ1 of the intermediate transfer body 4 in a range where no scattering occurs in the intermediate transfer body 4 having elasticity.

この結果から、感光体から中間転写体４への転写時の飛び散りの発生を防ぐためには、０．０５≦ｔａｎδ１≦０．４０であることが必要である。

From this result, it is necessary that 0.05 ≦ tan δ1 ≦ 0.40 in order to prevent the occurrence of scattering during transfer from the photosensitive member to the intermediate transfer member 4.

  As the cleaning blade 19, six types of times of immersion in the MDI bath were set as shown in Table 2, and the other conditions were set in the same manner. The loss tangent of each cleaning blade is also shown in Table 2. The occurrence of defective cleaning in Table 2 is indicated by No. 1 in Table 1. No. 3 intermediate transfer member was used for verification.

上記種々の中間転写体４とクリーニングブレード１９を用いた画像形成装置を用いて５００００枚通紙耐久後の転写性能とクリーニング性能を評価した。

Using the image forming apparatus using the various intermediate transfer bodies 4 and the cleaning blade 19, the transfer performance and the cleaning performance after passing through 50,000 sheets were evaluated.

  No. in Table 1 1, when tan δ1 of the intermediate transfer member 4 is 0.03, tan δ1 is too small and the intermediate transfer member 4 cannot be deformed according to the unevenness of the toner image on the photosensitive member 1. Then, a gap was generated between the intermediate body 4 and the photoconductor 1 at the contour portion of the toner image on the photoconductor 1 and scattering occurred.

  In Table 1, No. When the tan δ1 of the intermediate transfer body 4 is 0.50 as in 5, the tan δ1 is too large and it takes time to deform. Accordingly, it takes time until the intermediate transfer body 4 is deformed so as to follow the unevenness formed by the toner image on the photoreceptor 1, and between the photoreceptor 1 and the intermediate transfer body 4 at the contour portion of the toner image. There was a gap in the surface, and scattering occurred.

  On the other hand, no. When the tan δ1 of the intermediate transfer member 4 is in the range of 0.05 to 0.40 (0.05 ≦ tan δ1 ≦ 0.40) as in 2 to 4, the intermediate transfer member 4 has a toner image on the photosensitive member 1. The intermediate transfer body 4 can be quickly deformed so as to follow the irregularities formed by the above. Therefore, no scattering occurs.

  No. in Table 1 In the case where the intermediate transfer member 4 as shown in FIGS. 1, when the total tan δ 2 of the hardened layer and the base material of the cleaning blade 19 in the vicinity of the contact portion is 0.10, the loss tangent tan δ 2 of the cleaning blade 19 is too small, and the cleaning blade 19 is attached to the intermediate transfer body 4. The behavior when moved in response to vibration was not quickly attenuated, the contact of the cleaning blade 19 to the intermediate transfer member 4 was poor, and a cleaning failure occurred.

  In Table 2, No. 6, when the loss tangent tan δ2 of the cleaning blade 19 in the vicinity of the contact portion is 0.50, the loss tangent tan δ2 of the cleaning blade 19 is too large, and the time required for deformation becomes long. Here, the cleaning belt 19 could not be deformed along the unevenness of the surface of the intermediate transfer body 4, and a cleaning failure occurred.

  Therefore, no. In the case where the intermediate transfer member 4 as shown in FIGS. When the loss tangent tan δ2 of the cleaning blur cleaning blade 19 near the contact portion is in the range of 0.15 to 0.40 (0.15 ≦ tan δ2 ≦ 0.40) as in 2 to 5, the cleaning blade 19 The contact property to the intermediate transfer member 4 is improved, and the cleaning blade 19 can be deformed along the unevenness of the surface of the intermediate transfer member 4. Therefore, it was possible to suppress the occurrence of defective cleaning.

  No. in Table 1 No. 2 to No. 4 in Table 2 were used. Even if 2 to 4 cleaning blades 19 were used, good cleaning performance could not be obtained. It depends on each combination.

  Table 3 shows the results of cleaning performance after endurance of 50,000 sheets when each of the above is combined.

表１のＮｏ．２〜４のような中間転写体４を使いこなす場合において、中間転写体４の損失正接ｔａｎδ２と、クリーニングブレード１９の損失正接ｔａｎδ２の和（＝ｔａｎδ１＋ｔａｎδ２）が０. ２０のときには、損失正接が小さ過ぎて、クリーニングブレード１９と中間転写体４の当接部での双方の相対的な振動が速やかに減衰せず、クリーニングブレード１９と中間転写体４の間に間隙が生じ、クリーニング不良が発生する。

No. in Table 1 In the case where the intermediate transfer body 4 such as 2 to 4 is used, when the sum of the loss tangent tan δ2 of the intermediate transfer body 4 and the loss tangent tan δ2 of the cleaning blade 19 (= tan δ1 + tan δ2) is 0.20, the loss tangent is too small. As a result, the relative vibration of both the cleaning blade 19 and the contact portion between the intermediate transfer body 4 is not quickly attenuated, and a gap is generated between the cleaning blade 19 and the intermediate transfer body 4 to cause a cleaning failure.

  When the sum of the loss tangent of the intermediate transfer member 4 and the loss tangent of the cleaning blade 19 (= tan δ1 + tan δ2) was 0.25 or more, no cleaning failure occurred.

  When the sum of the loss tangent tan δ1 of the intermediate transfer member 4 and the loss tangent tan δ2 of the cleaning blade 19 (= tan δ1 + tan δ2) is 0.70 or 0.80, the loss tangent tan δ2 of the intermediate transfer member 4 and the cleaning blade 19 The sum of the loss tangent tan δ2 is large, and it takes time for the intermediate transfer member 4 and the cleaning blade 19 to deform along the unevenness of the surface of the intermediate transfer member 4. Therefore, the intermediate transfer body 4 and the cleaning blade 19 cannot be deformed along the unevenness of the surface of the intermediate transfer body 4, and a gap is generated between the intermediate transfer body 4 and the cleaning blade 19, resulting in poor cleaning. .

  The sum of the loss tangent tan δ1 of the intermediate transfer member 4 and the loss tangent tan δ2 of the cleaning blade 19 (= tan δ1 + tan δ2) was good when it was 0.65 or less.

  Therefore, no. When the intermediate transfer member 4 such as 2 to 4 is used, the sum of the loss tangent tan δ1 of the intermediate transfer member 4 and the loss tangent tan δ2 of the cleaning blade 19 (= tan δ1 + tan δ2) is in the range of 0.25 to 0.65 (0 .25 ≦ tan δ1 + tan δ2 ≦ 0.65), it has vibration damping properties and can be deformed corresponding to the irregularities on the surface, so that good cleaning characteristics without defective cleaning can be obtained.

<Embodiment 2>
Next, a second embodiment of the present invention will be described.

  The present embodiment is an example in which the present invention is applied to an image forming apparatus different from the first embodiment. The image forming apparatus is shown in FIG.

  In FIG. 10, the image forming process of the image forming apparatus according to the present embodiment is substantially the same as that of the image forming apparatus according to the first embodiment, and a description thereof will be omitted.

  A feature of the image forming apparatus according to the present embodiment is that it is a tandem system having four photoconductors 1a, 1b, 1c, and 1d and is excellent in high-speed performance. In each of the photoreceptors 1a to 1d, charging, latent image formation, and development steps are performed to form toner images of each color, and the toner images are sequentially superimposed on the intermediate transfer member 4, and the toner images on the intermediate transfer member 4 are overlapped. A color image is obtained by batch transfer to a transfer material.

  Thus, the image forming apparatus according to the present embodiment employs a cleaningless system that includes the cleaning device 17 that cleans the intermediate transfer body 4 but does not have a cleaning device that cleans the photoreceptors 1a to 1d. .

  Also in such an image forming apparatus, the same effect as in the first embodiment can be obtained.

<Embodiment 3>
Next, a third embodiment of the present invention will be described.

  The present embodiment is an example in which the present invention is applied to an image forming apparatus different from the first embodiment. The image forming apparatus is shown in FIG.

  Since the image forming process of the image forming apparatus according to the present embodiment is substantially the same as that of the image forming apparatus according to the first embodiment, description thereof will be omitted.

  A feature of the image forming apparatus according to the present embodiment is a tandem image forming apparatus having four photoreceptors 1a, 1b, 1c, and 1d, and is excellent in high speed. In this image forming apparatus, each of the photoconductors 1a to 1d is subjected to charging, latent image formation, and development processes to form toner images of each color, and this toner image is directly superimposed on the transfer material on the transfer belt 21 sequentially. Combine to get an image. The direct transfer belt 21 is provided with a cleaning device 17 for cleaning toner overflowing from the end of the transfer material, scattered toner, or fog toner between the transfer materials.

  Also in such an image forming apparatus, the same effect as in the first embodiment can be obtained.

  The present invention is effective for an image forming apparatus such as a color copying machine or a color printer that includes a cleaning device for cleaning an intermediate transfer member and forms a color image using an electrophotographic process.

1 is a schematic cross-sectional view of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a side sectional view of a cleaning device provided in the image forming apparatus according to Embodiment 1 of the present invention. It is the schematic which shows the preparation methods of a cleaning blade. FIG. 3 is a cross-sectional view illustrating a layer configuration of an intermediate transfer member. It is a perspective view which shows the test piece for measuring the loss tangent tan-delta 2 of a cleaning blade. It is a perspective view which shows another shape of the test piece for measuring the loss tangent tan-delta 2 of a cleaning blade. It is a perspective view which shows another shape of the test piece for measuring the loss tangent tan-delta 2 of a cleaning blade. FIG. 6 is a perspective view showing a test piece for measuring a loss tangent tan δ1 of an intermediate transfer member. FIG. 5 is a perspective view showing another shape of a test piece for measuring the loss tangent tan δ1 of the intermediate transfer member. It is a schematic sectional drawing of the image forming apparatus which concerns on Embodiment 2 of this invention. It is a schematic sectional drawing of the image forming apparatus which concerns on Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging means 4 Intermediate transfer body (image carrier)
6 Photosensitive member cleaning device 7 Laser oscillator 8 Developing means 10 Secondary transfer roller 12 Primary transfer roller 16 Developing rotary 17 Intermediate transfer body cleaning device 18 Fixing means 19 Intermediate transfer body cleaning blade (blade member)
20 Casing of intermediate transfer member cleaning device 200 Second test piece 210 First test piece

Claims (4)

An intermediate transfer member having an elastic layer, a transfer means for transferring the toner image carried on the intermediate transfer member to a recording medium, an edge is in contact with the intermediate transfer member , and the toner image is transferred to the recording medium A blade member that removes toner remaining on the intermediate transfer body after being removed from the intermediate transfer body ,
The loss tangent tan δ1 of the first test piece that is cut and molded from the intermediate transfer member so as to include the surface in contact with the blade member is 0.05 ≦ tan δ1 ≦ 0.40,
The loss tangent tan δ2 of the second test piece formed by cutting out a part of the blade member so as to include the edge contacting the intermediate transfer member and the two surfaces forming the edge is 0.15 ≦ tan δ2 ≦ 0. .40 in the image forming apparatus,
The blade member is arranged such that the linear pressure N (g / cm) of the blade member against the intermediate transfer member satisfies 20 <N <60,
The loss tangent tan δ1 of the intermediate transfer member and the loss tangent δ2 of the blade member are:
0.25 ≦ tan δ1 + tan δ2 ≦ 0.65
The loss tangent of each of the intermediate transfer member and the blade member is set so as to satisfy the above . The contact angle θ (degree) of the blade member with respect to the intermediate transfer member is
15 ≦ θ ≦ 35
The image forming apparatus according to claim 1 , wherein the blade member is disposed so as to satisfy the above condition . Toner having an elastic layer, and a transfer belt for carrying the recording material, a transfer unit that transfers the toner image to the recording material borne on the transfer belt, which edge is in contact with the transfer belt, remaining on the transfer belt A blade member that removes from the transfer belt ,
The loss tangent tan δ1 of the first test piece cut and molded so as to include the surface in contact with the blade member from the transfer belt is 0.05 ≦ tan δ1 ≦ 0.40,
The loss tangent tan δ2 of the second test piece formed by cutting a part of the blade member so as to include the edge contacting the transfer belt and the two surfaces forming the edge is 0.15 ≦ tan δ2 ≦ 0. In the image forming apparatus 40 ,
The blade member is arranged so that the linear pressure N (g / cm) of the blade member against the transfer belt satisfies 20 <N <60,
The loss tangent tan δ1 of the transfer belt and the loss tangent δ2 of the blade member are:
0.25 ≦ tan δ1 + tan δ2 ≦ 0.65
An image forming apparatus , wherein loss tangents of the transfer belt and the blade member are set so as to satisfy The contact angle θ (degree) of the blade member to the transfer belt is
15 ≦ θ ≦ 35
The image forming apparatus according to claim 3 , wherein the blade member is disposed so as to satisfy the above condition .

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