Method for manufacturing solid lubricants

Abstract

The object of the present invention is to provide a method for manufacturing a solid lubricant that reduces the amount of wear on the solid lubricant, minimizes variations in the amount of wear, allows for a stable supply of the minimum necessary amount of lubricant, and has good moldability. [Solution] The present invention provides a method for manufacturing a solid lubricant, which is applied to the surface of an image carrier in an electrophotographic image forming apparatus to form a film on the surface of the image carrier. The method for manufacturing a solid lubricant comprises a step (I) in which the main component, a higher fatty acid metal salt, and the secondary component, a higher fatty acid metal salt, are heated and melted to form a molten product, and a step (II) in which the molten product is cooled to obtain a solid lubricant. In steps (I) and (II), the sum of the temperatures of the molten product obtained every second that are above the melting point of the main component, the higher fatty acid metal salt, is 700,000°C or less.

Description

Technical Field

[0001] The present invention relates to a method for producing a solid lubricant. In particular, the present invention relates to a method for producing a solid lubricant with less chipping amount and less variation in the chipping amount, and good formability.

Background Art

[0002] In image forming apparatuses such as copiers, printers, and facsimile apparatuses using an electrophotographic method, toner remaining on the surface of a photoreceptor is recovered by a method such as scraping it off with a cleaning blade in a cleaning unit. However, when scraping off toner remaining on the surface of the photoreceptor with a cleaning blade, if the frictional force between the cleaning blade and the photoreceptor is high, it causes blade friction and film chipping on the surface of the photoreceptor, shortening their respective lifetimes.

[0003] In such image forming apparatuses using an electrophotographic method, conventionally, a rod-shaped solid lubricant is cut on the surface of a photoreceptor by means such as a coating brush, and the cut powder of the solid lubricant is applied to the surface of the photoreceptor to reduce the coefficient of friction on the surface of the photoreceptor and prevent adhesion of unnecessary toner. Particularly, in an image forming apparatus that cleans the residual toner on the surface of the photoreceptor with a cleaning blade, when a lubricant is supplied onto the photoreceptor, the coefficient of friction between the photoreceptor and the cleaning blade decreases, the cleaning performance improves, and the lifetimes of the photoreceptor and the cleaning blade can be extended.

[0004] As disclosed in Patent Document 1, for example, in the case of a solid lubricant, after pouring molten higher fatty acid metal salt into a mold, the molten higher fatty acid metal salt is sequentially cooled and solidified from the bottom to the top to prevent cracking during molding.

[0005] However, according to the method for manufacturing solid lubricants disclosed in Patent Document 1, the amount of solid lubricant worn away increases. As a result, the consumption of solid lubricant increases, leading to an earlier stage of cleaning failure due to depletion of the solid lubricant, and resulting in a shortened lifespan for the photoreceptor and cleaning blade. On the other hand, if the amount of solid lubricant removed is too little, it can lead to accelerated wear of the photoreceptor and cleaning blade, a decrease in cleaning performance, and a deterioration of image quality. Therefore, it is desirable that the amount of solid lubricant removed is neither too much nor too little. Furthermore, in order to extend the lifespan of the photoreceptor and cleaning blade, it is important to supply the minimum necessary amount of lubricant stably. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 7-26278 [Overview of the project] [Problems that the invention aims to solve]

[0007] This invention has been made in view of the above-mentioned problems and circumstances. The problem to be solved by this invention is to provide a method for manufacturing a solid lubricant that reduces the amount of wear on the solid lubricant, reduces variations in the amount of wear, allows for the stable supply of the minimum necessary amount of lubricant, and has good moldability. [Means for solving the problem]

[0008] The inventors of the present invention investigated the causes of the above problems in order to solve them. The inventors of the present invention found that by specifying the melting time of the main material and auxiliary material, it is possible to provide a method for manufacturing a solid lubricant that reduces the amount of wear on the solid lubricant, reduces variations in the amount of wear, allows for a stable supply of the minimum necessary amount of lubricant, and has good moldability. In other words, the above-mentioned problems according to the present invention are solved by the following means.

[0009] 1. A method for manufacturing a solid lubricant to be applied to the surface of an image carrier in an electrophotographic image forming apparatus to form a film on the surface of the image carrier, The solid lubricant contains a higher fatty acid metal salt as the main component and a higher fatty acid metal salt as the secondary component, The process (I) involves heating and melting the main material, which is the higher fatty acid metal salt, and the auxiliary material, which is the higher fatty acid metal salt, to form a molten product. The process includes (II) cooling the molten material to obtain the solid lubricant, In steps (I) and (II) described above, the sum of the temperatures of the molten material obtained every second that are equal to or greater than the melting point of the main component, the higher fatty acid metal salt, is 700,000°C or less. A method for producing a solid lubricant, characterized by the following:

[0010] 2. The main material, the higher fatty acid metal salt, is zinc stearate. A method for producing a solid lubricant as described in paragraph 1, characterized by the above.

[0011] 3. In steps (I) and (II) above, the sum of the temperatures of the molten material obtained every second that are equal to or greater than the melting point of the main component, the higher fatty acid metal salt, is 300,000°C or less. A method for producing a solid lubricant as described in paragraph 1, characterized by the above.

[0012] 4. The melting point of the aforementioned auxiliary material, the higher fatty acid metal salt, is within the range of 80 to 230°C. A method for producing a solid lubricant as described in paragraph 1, characterized by the above.

[0013] 5. The metal content of the secondary material, the higher fatty acid metal salt, is within the range of 0.25 to 5% by mass in terms of metal, relative to the metal content of the main material, the higher fatty acid metal salt. A method for producing a solid lubricant according to any one of paragraphs 1 to 4, characterized by the above. [Effects of the Invention]

[0014] The present invention provides a method for manufacturing a solid lubricant that reduces the amount of wear on the solid lubricant, minimizes variations in the amount of wear, allows for stable supply of the minimum necessary amount of lubricant to the photoreceptor and the like, and provides good moldability. Although the mechanism of action or mechanism of the present invention is not yet clear, it is speculated as follows. In the present invention's method for producing a solid lubricant, two or more types of higher fatty acid metal salts are used as the main material and auxiliary material. Therefore, when the molten material containing the main material and auxiliary material is solidified, crystal nuclei are formed and crystal growth is promoted. The presence of crystals in the solidified solid lubricant reduces the amount of wear on the solid lubricant, but increases the variability in the amount of wear. In other words, when two or more higher fatty acid metal salts are included in a solid lubricant, the higher fatty acid metal salts act as crystal nuclei, causing crystals to grow and making the solid lubricant less susceptible to wear. For example, Figure 5 is a photograph of the solid lubricant according to the present invention taken with an optical microscope (DSX1000, manufactured by Olympus Corporation), and the symbol C in Figure 5 indicates a crystal that has developed spherically around a crystal nucleus. However, if the molten material is continuously heated in its molten state, the material deteriorates, and the area surrounding the crystal growth point (C) becomes more brittle. As the abrasion progresses, the crystal growth point (C) becomes more likely to break off entirely, which causes inconsistencies in the amount of material removed. Therefore, in this invention, by specifying the time for mixing and melting the main material and auxiliary material, material degradation due to melting is prevented, and as a result, the amount of wear on the solid lubricant is reduced. In addition, the difference in the amount of wear between areas where crystal growth has occurred (C) and areas where it has not is reduced, and the variation in the amount of wear is reduced. Furthermore, the minimum necessary amount of lubricant can be stably supplied to photoreceptors, etc. In addition, a solid lubricant with good moldability can be obtained. [Brief explanation of the drawing]

[0015] [Figure 1] A diagram showing the relationship between temperature and time when the main and secondary materials are melted. [Figure 2] A schematic diagram showing an example of the configuration of an image forming apparatus. [Figure 3] A schematic diagram showing an example of the configuration of a lubricant application means. [Figure 4] Schematic diagram showing another example of the configuration of the lubricant application means [Figure 5] Optical microscope photograph of the solid lubricant according to the present invention

Mode for Carrying Out the Invention

[0016] A method for producing a solid lubricant that is applied to the surface of an image carrier of an image forming apparatus in an electrophotographic system of the present invention to form a film on the surface of the image carrier, wherein the solid lubricant contains a higher fatty acid metal salt as a main material and a higher fatty acid metal salt as a subsidiary material, and a step (I) of heating and melting the higher fatty acid metal salt as the main material and the higher fatty acid metal salt as the subsidiary material to obtain a melt, and a step (II) of cooling the melt to obtain the solid lubricant, and in the step (I) and the step (II), among the respective temperatures of the melt obtained every 1 second, the total value of the temperatures that are equal to or higher than the melting point of the higher fatty acid metal salt as the main material is 700,000 °C or lower. This feature is a technical feature common to or corresponding to each of the following embodiments.

[0017] As an embodiment of the present invention, it is preferable that the higher fatty acid metal salt as the main material is zinc stearate in terms of being easy to spread and being able to be evenly supplied to the surface of the photoreceptor.

[0018] In the step (I) and the step (II), among the respective temperatures of the melt obtained every 1 second, it is preferable that the total value of the temperatures that are equal to or higher than the melting point of the higher fatty acid metal salt as the main material is 300,000 °C or lower. Thereby, the amount of shaving of the solid lubricant is less, and the variation in the amount of shaving is also smaller.

[0019] It is preferable that the melting point of the higher fatty acid metal salt as the subsidiary material is within the range of 80 to 230 °C in terms of compatibility with the main material.

[0020] Preferably, the metal content of the auxiliary material, the higher fatty acid metal salt, is within the range of 0.25 to 5% by mass in terms of metal, relative to the metal content of the main material, the higher fatty acid metal salt. This allows for the formation of crystal nuclei when the molten mixture of the main and auxiliary materials is solidified, resulting in less wear on the solid lubricant.

[0021] The present invention, its components, and embodiments for carrying out the present invention will be described below. In this application, "~" is used to mean that the numerical values ​​written before and after it are included as the lower limit and upper limit.

[0022] [Overview of the method for producing the solid lubricant of the present invention] The present invention relates to a method for producing a solid lubricant, which is applied to the surface of an image carrier in an electrophotographic image forming apparatus to form a film on the surface of the image carrier, wherein the solid lubricant contains a higher fatty acid metal salt as a main component and a higher fatty acid metal salt as a secondary component, and comprises the steps of (I) heating and melting the higher fatty acid metal salt as the main component and the higher fatty acid metal salt as the secondary component to form a molten product, and (II) cooling the molten product to obtain the solid lubricant. In steps (I) and (II) described above, the sum of the temperatures of the molten material obtained every second that are above the melting point of the main material, the higher fatty acid metal salt, is 700,000°C or less.

[0023] Solid lubricants are obtained by melting a main component, a higher fatty acid metal salt, and a secondary component, a higher fatty acid metal salt, and then cooling and solidifying them into a desired shape. Solid lubricants can be manufactured in rod or block form by a melt molding method in which at least the main component and secondary component are mixed and melted, and the resulting molten material is injected into a mold. In this invention, the main material refers to the material that constitutes the solid lubricant, and which accounts for 50% or more by mass of the total material of the solid lubricant. The main material is a higher fatty acid metal salt. Auxiliary materials are components of a solid lubricant, excluding the main material, and account for less than 50% by mass of the total lubricant material. Furthermore, auxiliary materials are higher fatty acid metal salts having a different type of metal salt than the main material. It is preferable to use one or more types of auxiliary materials.

[0024] The method for producing a solid lubricant comprises steps (I) and (II). <Process (I)> In process (I), the main component, a higher fatty acid metal salt, and the secondary component, a higher fatty acid metal salt, are heated and melted to form a molten product. Metal salts of higher fatty acids are metal salts of higher fatty acids, and can be obtained, for example, by neutralizing a higher fatty acid with an alkaline compound containing a metal.

[0025] (higher fatty acids) The higher fatty acids that can constitute the higher fatty acid metal salt, which is the main or secondary component, are preferably fatty acids with 12 or more carbon atoms, and preferably fatty acids with 30 or fewer carbon atoms. In particular, fatty acids with 16 to 22 carbon atoms are preferred. If the number of carbon atoms is 12 or more, the interlayer attractive forces of the crystal do not become too strong, and the ductility and fractureability of the crystal do not decrease. Therefore, when polished by the lubricant application method described later, the risk of localized supply shortages or a decrease in lubrication function can be avoided. If the number of carbon atoms is 30 or less, the interlayer attractive forces of the crystal will not become too low, thus preventing the entire lubricant from becoming brittle. As a result, the risk of generating coarse particles when polished by the lubricant application method can be avoided.

[0026] Furthermore, it is preferable that the higher fatty acids do not contain unsaturated bonds. With such fatty acids, the polarity of the unsaturated bonds prevents the interlayer attractive forces of the crystal from becoming stronger. As a result, the ductility and fracture properties of the crystal do not decrease, thus avoiding the risk of localized supply shortages or reduced lubrication when polished by a lubricant application method.

[0027] Specific examples of the aforementioned higher fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, palmitoleic acid, oleic acid, elaidic acid, ricinoleic acid, eicosenoic acid, erucic acid, linoleic acid, gamma-linolenic acid, alpha-linolenic acid, punicic acid, and stearic acid.

[0028] From the viewpoint of the number of carbon atoms and the presence or absence of unsaturated bonds, stearic acid is preferred as the higher fatty acid. This avoids the risk of localized supply shortages, reduced lubrication function, and generation of coarse particles when polished by the lubricant application means described later.

[0029] (Metal salts) Examples of metal salts that can constitute the main or secondary component of a higher fatty acid metal salt include lithium, sodium, potassium, magnesium, calcium, barium, aluminum, gallium, and zinc.

[0030] The aforementioned higher fatty acid metal salts are more preferably chain monocarboxylic acids, and even more preferably saturated chain monocarboxylic acids and their metal salts, particularly those having 16 to 22 carbon atoms, specifically zinc stearate, magnesium stearate, and calcium stearate.

[0031] The main and auxiliary materials described above are thoroughly mixed and heated to melt them into a molten material. Here, the temperature of the molten material is measured every second. The temperatures obtained every second that are above the melting point of the main material, the higher fatty acid metal salt, are summed up. The heating is then controlled so that this sum is 700,000°C or less. Let's explain this with reference to Figure 1. Figure 1 shows the case where the melting point of the main material is 110°C. In this case, the mixture is heated, and the temperature is measured every second from the moment it reaches the melting point of 110°C. The temperatures measured every second are then added together, and the heating and cooling are controlled so that the total sum is 700,000°C or less. In Figure 1, the total sum of the temperatures measured every second between point A and point B is set to be 700,000°C or less. One means of keeping the sum of the aforementioned temperatures below 700,000°C is to melt the material at a low temperature (slightly above the melting point) in a short time. Methods for melting in a short time include (i) increasing the surface area of ​​the melting furnace and (ii) using a stirring mechanism.

[0032] <Process (II)> In step (II), the molten material is cooled to obtain a solid lubricant. In order to keep the sum of the aforementioned temperatures below 700,000°C, possible methods include increasing the cooling rate during the solidification of the molten material. Specifically, the molten material is poured into the mold, and the cooling rate is preferably in the range of 2 to 10°C / min.

[0033] Furthermore, the solid lubricant according to the present invention may contain additives other than the main and auxiliary materials described above. Examples of additives include saturated fatty acids (capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid) and fatty acid amides.

[0034] [Image forming apparatus] Next, we will describe an electrophotographic image forming apparatus that uses the solid lubricant obtained by the manufacturing method described above. Figure 2 is a schematic diagram showing an example of the configuration of an image forming apparatus. Figures 3A and 3B are schematic diagrams showing an example of the configuration of a lubricant application means.

[0035] The image forming apparatus comprises at least a rotatable image carrier, a charging means for charging the image carrier, and a toner image transfer means for transferring a toner image carried on the charged image carrier to a transfer material. Furthermore, the image forming apparatus has a lubricant application means positioned between the toner image transfer means and the charging means in the rotational direction of the image carrier, for applying a lubricant to the surface of the image carrier. Such an image forming apparatus can be configured in the same way as known image forming apparatuses.

[0036] The lubricant application means comprises a solid lubricant obtained by the manufacturing method described above, a lubricant application member for applying the solid lubricant to the surface of the image carrier, and a lubricant supply means for supplying the solid lubricant to the lubricant application member. It is preferable that the lubricant application member is flexible and can be positioned to contact the surface of the image carrier.

[0037] The image forming apparatus 1 shown in Figure 2 includes an image reading unit 110, an image processing unit 30, an image forming unit 40, a paper transport unit 50, and a fixing device 60.

[0038] The image forming unit 40 includes image forming units 41Y, 41M, 41C, and 41K that form images using toners of color Y (yellow), M (magenta), C (cyan), and K (black). Since these units all have the same configuration except for the toner they contain, the symbols representing the colors may be omitted hereafter. The image forming unit 40 further includes an intermediate transfer unit 42 and a secondary transfer unit 43. These correspond to toner image transfer means.

[0039] The image forming unit 41 includes an exposure device 411, a developing device 412, a photoreceptor drum 413, a charging device 414 which is a charging means, and a cleaning device 415 which will be described later. The photoreceptor drum 413 is, for example, a negatively charged organic photoreceptor. The surface of the photoreceptor drum 413 is photoconductive. The photoreceptor drum 413 corresponds to the image carrier.

[0040] The charging device 414 is, for example, a corona charger. The charging device 414 may also be a contact charging device that charges the photoreceptor drum 413 by bringing contact charging members such as charging rollers, charging brushes, or charging blades into contact with it. The exposure device 411 includes, for example, a semiconductor laser as a light source and a light deflection device (polygon motor) that irradiates the photoreceptor drum 413 with laser light corresponding to the image to be formed.

[0041] The developing apparatus 412 is a developing apparatus that uses a two-component developing method. The developing apparatus 412 includes a developing container, developing rollers (magnetic rollers), a partition wall, a transport roller, and an agitation roller. The developing container holds a two-component developer. The developing roller is rotatably positioned at the opening of the developing container. A partition wall divides the inside of the developing container, allowing the two-component developer to communicate with each other. A transport roller conveys the two-component developer from the opening side of the developing container toward the developing roller. A stirring roller agitates the two-component developer inside the developing container. The developing container contains the toner described above as the two-component developer.

[0042] The intermediate transfer unit 42 includes an intermediate transfer belt 421, a primary transfer roller 422 that presses the intermediate transfer belt 421 against the photoreceptor drum 413, a plurality of support rollers 423 including a backup roller 423A, and a belt cleaning device 426. The intermediate transfer belt 421 is stretched in a loop around a plurality of support rollers 423. The intermediate transfer belt 421 travels at a constant speed in the direction of arrow X as at least one of the drive rollers among the plurality of support rollers 423 rotates. In the image forming apparatus 1 shown in Figure 2, the primary transfer roller 422 corresponds to the toner image transfer means, and the intermediate transfer belt 421 corresponds to the transfer material.

[0043] The secondary transfer unit 43 has an endless secondary transfer belt 432 and a plurality of support rollers 431 including a secondary transfer roller 431A. The secondary transfer belt 432 is stretched in a loop shape by the secondary transfer roller 431A and the support rollers 431.

[0044] The cleaning device 415 includes a cleaning container 415A and a cleaning blade 415B. The cleaning container 415A opens toward the photoreceptor drum 413. The cleaning blade 415B is positioned at the opening of the cleaning container 415A so as to be in contact with the surface of the photoreceptor drum 413. The cleaning blade 415B is, for example, an elastic blade made of rubber.

[0045] The cleaning container 415A includes a rotating brush 416A, a solid lubricant 416B, and a biasing member 416C. The rotating brush 416A contacts the surface of the photoreceptor drum 413. The solid lubricant 416B contacts the surface of the rotating brush 416A. The biasing member 416C biases the solid lubricant 416B toward the rotating brush 416A. The rotating brush 416A, the solid lubricant 416B, and the biasing member 416C correspond to the lubricant application means 416 for applying the lubricant to the surface of the photoreceptor drum 413, which is an image carrier. These rotating brushes 416A, solid lubricant 416B, and biasing member 416C are positioned from the toner image transfer means to the charging means in the rotational direction of the image carrier.

[0046] Solid lubricant 416B is a solid lubricant manufactured by the manufacturing method of the present invention. The shape of the solid lubricant 416B can be appropriately determined within the range that can be applied to the surface of the photoreceptor drum 413 by the rotating brush. Preferably, the solid lubricant 416B is a rectangular parallelepiped having a length equal to the axial length of the rotating brush 416A.

[0047] The rotating brush 416A is configured to rotate freely in the forward or reverse direction relative to the photoreceptor drum 413. The rotating brush 416A is not particularly limited as long as it can apply a solid lubricant to the surface of the image carrier. An example of a rotating brush 416A is a rotating brush composed of a rotatable metal shaft and a plurality of flexible resin bristles that rise from the circumferential surface of the shaft. This rotating brush 416A corresponds to a lubricant application member that is flexible and positioned to contact the surface of the image carrier.

[0048] The biasing member 416C is a member for biasing and pressing the solid lubricant 416B toward the rotating brush 416A. The biasing member 416C is, for example, an elastic member such as a coil spring or a leaf spring. The biasing member 416C corresponds to a lubricant supply means for supplying the solid lubricant to the lubricant application member.

[0049] The fixing device 60 includes, for example, a fixing roller 62, a heating belt 63, and a pressure roller 64. The heating belt 63 is an endless belt that covers the outer surface of the fuser roller 62 and heats and melts the toner that makes up the toner image on the paper S. The pressure roller 64 presses the paper S toward the fuser roller 62 and the heating belt 63. The paper S corresponds to the recording medium.

[0050] The image forming apparatus 1 further includes an image reading unit 110, an image processing unit 30, and a paper transport unit 50. The image reading unit 110 includes a paper feeder 111 and a scanner 112. The paper transport unit 50 includes a paper feed unit 51, a paper discharge unit 52, and a transport path unit 53. The three paper feed tray units 51a to 51c that make up the paper feed unit 51 accommodate paper S (standard paper, special paper) identified based on basis weight, size, etc., according to pre-set types. The transport path unit 53 has multiple transport roller pairs, such as registration roller pairs 53a.

[0051] The image formation method using the image forming apparatus 1 will be described below. The image forming method using the image forming apparatus 1 comprises an image carrier charging step, an electrostatic latent image formation step, a toner image carrying step, a toner image transfer step, and a step of forming a lubricant layer. The image carrier charging step is a step of charging the photoreceptor drum 413. The electrostatic latent image formation step is a step of forming an electrostatic latent image on the charged photoreceptor drum 413. The toner image carrying step is a step of supplying toner to the photoreceptor drum 413 on which the electrostatic latent image has been formed to carry a toner image. The toner image transfer step is a step of transferring the toner image carried on the photoreceptor drum 413 to a transfer material. The lubricant layer forming step is a step of applying lubricant supplied from solid lubricant 416B to the surface of the photoreceptor drum 413 after the toner image has been transferred to form a lubricant layer.

[0052] First, the scanner 112 optically scans and reads the original document D on the contact glass. The reflected light from the original document D is read by the CCD sensor 112a and becomes the input image data. The input image data is subjected to predetermined image processing in the image processing unit 30 and sent to the exposure device 411.

[0053] The photoreceptor drum 413 rotates at a constant peripheral speed. The charging device 414 uniformly charges the surface of the photoreceptor drum 413 with negative polarity. In the exposure device 411, the polygon mirror of the polygon motor rotates at high speed, and laser light corresponding to the input image data for each color component is unfolded along the axial direction of the photoreceptor drum 413. This light is then irradiated onto the outer surface of the photoreceptor drum 413 along the axial direction. In this way, an electrostatic latent image is formed on the surface of the photoreceptor drum 413.

[0054] In the developing device 412, toner particles become charged by agitation and transport of the two-component developer in the developing container. The two-component developer is transported to the developing roller, where a magnetic brush is formed on the surface of the developing roller. The charged toner particles electrostatically adhere from the magnetic brush to the portion of the electrostatic latent image on the photoreceptor drum 413. In this way, the electrostatic latent image on the surface of the photoreceptor drum 413 is made visible, and a toner image corresponding to the electrostatic latent image is formed on the surface of the photoreceptor drum 413.

[0055] The toner image on the surface of the photoreceptor drum 413 is transferred to the intermediate transfer belt 421 by the intermediate transfer unit 42. The intermediate transfer belt 421 is pressed against the photoreceptor drum 413 by the primary transfer roller 422, forming a primary transfer nip for each photoreceptor drum 413 by the photoreceptor drum 413 and the intermediate transfer belt 421. In this primary transfer nip, the toner images of each color are sequentially transferred and overlapped onto the intermediate transfer belt 421.

[0056] After the transfer, a fine powder of lubricant is supplied to and applied to the surface of the photoreceptor drum 413 by a rotating brush 416A, which is pressed against the solid lubricant 416B, and the rotating brush 416A scrapes off the solid lubricant 416B.

[0057] The portion of the photoreceptor drum 413 surface to which the above lubricant has been applied reaches the cleaning blade 415B. The residual toner and excess lubricant on the surface of the photoreceptor drum 413 are scraped off by the cleaning blade 415B and collected in the container (cleaning process). In this way, the residual toner is removed from the surface, and the lubricant is evenly spread across the surface, forming a layer of lubricant. The formation of the lubricant layer reduces the adhesion between the toner and the photoreceptor drum 413, improving the ability to scrape off the toner and suppressing cleaning defects.

[0058] Furthermore, by applying a lubricant to the surface, the friction between the cleaning blade 415B and the surface of the photoreceptor drum 413 that contacts the surface is reduced along the entire length of contact of the cleaning blade 415B. As a result, wear of the cleaning blade 415B is suppressed, and wear of the surface of the photoreceptor drum 413 is also suppressed.

[0059] On the other hand, the secondary transfer roller 431A is pressed against the backup roller 423A via the intermediate transfer belt 421 and the secondary transfer belt 432. As a result, the intermediate transfer belt 421 and the secondary transfer belt 432 form a secondary transfer nip. The paper S passes through this secondary transfer nip. The paper S is transported to the secondary transfer nip by the paper transport unit 50. Correction of the tilt of the paper S and adjustment of the transport timing are performed by the register roller unit, where the register roller pair 53a is arranged.

[0060] When the paper S is transported to the secondary transfer nip, a transfer bias is applied to the secondary transfer roller 431A. This transfer bias causes the toner image supported on the intermediate transfer belt 421 to be transferred to the paper S by the secondary transfer nip. The paper S, on which the toner image has been transferred, is then transported toward the fuser 60 by the secondary transfer belt 432.

[0061] The fixing device 60 forms a fixing nip using a heating belt 63 and a pressure roller 64, and heats and pressurizes the conveyed paper S at the fixing nip. The toner particles that make up the toner image on the paper S are heated, the entire toner particle melts rapidly, the toner components adhere to the paper S, and then solidify rapidly. In this way, the toner image is fixed to the paper S. The paper S with the fixed toner image is discharged from the machine by the paper discharge section 52 equipped with a paper discharge roller 52a. In this way, a high-resolution image is formed.

[0062] Furthermore, any remaining toner on the surface of the intermediate transfer belt 421 after secondary transfer is removed by a belt cleaning device 426 having a belt cleaning blade that slides against the surface of the intermediate transfer belt 421.

[0063] The embodiments to which the present invention can be applied are not limited to those described above, and can be modified as appropriate without departing from the spirit of the invention. For example, the image forming apparatus 1 is not limited to the above configuration. Specifically, the image forming apparatus 1 has the lubricant application means 416 directly in front of the cleaning blade 415B, i.e., between the transfer device (primary transfer roller 422) and the cleaning blade 415B, with respect to the rotation direction of the photoreceptor drum. However, as shown in Figure 4, it may also be positioned directly behind the cleaning blade 415B, i.e., between the cleaning blade 415B and the charging device 414. Furthermore, the lubricant application means 416 may be located both between the toner image transfer means and the cleaning device 415, as shown in Figure 3, and between the cleaning device 415 and the charging device 414, as shown in Figure 4.

[0064] Furthermore, when positioned as shown in Figure 4, the lubricant application means may further include a member for leveling the applied lubricant, such as an elastic blade, elastic brush, elastic belt, or elastic roller positioned in contact with the surface of the photoreceptor drum 413.

[0065] Furthermore, the rotating brush 416A may be an elastic belt or elastic roller that contacts the surface of the photoreceptor drum 413 and is supplied with lubricant from the solid lubricant 416B, and may be another coating member capable of applying the lubricant to the surface of the photoreceptor drum 413. Moreover, both the rotating brush 416A and the other coating member may be arranged so as to contact the surface of the photoreceptor drum 413 only during application.

[0066] Furthermore, although the image forming apparatus 1 described above was explained as a solid lubricant 416B being a integrally molded rectangular block, the solid lubricant is not limited to a rectangular block; it can be in any form that can be applied to the surface of the photoreceptor drum 413. [Examples]

[0067] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. In the following examples, unless otherwise specified, the operations were carried out at room temperature (25°C). Unless otherwise specified, "%" and "parts" mean "mass%" and "parts by mass," respectively.

[0068] [Manufacturing of main and secondary materials] <Zinc stearate> Zinc stearate was prepared by reacting stearic acid with zinc hydroxide to achieve a metal content of 10% by mass. This zinc stearate was heated to 300°C at a heating rate of 10°C / min using a differential scanning calorimeter "DSC7000X" (manufactured by Hitachi High-Tech Science Corporation). The peak temperature obtained was defined as the melting point of zinc stearate.

[0069] <Calcium stearate, magnesium stearate, barium stearate, sodium stearate, zinc behenate, calcium laurate> Calcium stearate (CaSt) was prepared by reacting it with zinc stearate (CaSt) to obtain a metal content of 7% by mass, using the same method as described above. Magnesium stearate (MgSt) was also prepared by reacting it with a metal content of 4.5% by mass. Barium stearate (BaSt) was also prepared by reacting it with a metal content of 20% by mass. Furthermore, sodium stearate (NaSt) was prepared by reacting it with a metal content of 8% by mass. Zinc behenate (ZnBe) was prepared by reacting it with a metal content of 8.5% by mass. Calcium laurate (CaLa) was also prepared by reacting it with a metal content of 9% by mass. Furthermore, the melting points of each metal salt were measured using the same method as for zinc stearate. The metal content and melting points of each metal salt are shown in Table I below. The purity values ​​listed in Table I were determined by completely decomposing the raw material, higher fatty acid zinc, with nitric acid in a sealed microwave decomposition apparatus, diluting the decomposition solution with ultrapure water as appropriate, and quantifying each metal using an ICP emission spectrometer by the calibration curve method or the standard addition method.

[0070] [Table 1]

[0071] [Manufacturing of solid lubricants] <Manufacturing of Solid Lubricant 1> 100 parts by mass of the main material, zinc stearate, and 2.86 parts by mass of the secondary material, calcium stearate, were thoroughly mixed and heated to 150°C to melt, then stirred for 15 minutes. During this time, the temperature of the molten material was measured every second. From the obtained temperature data, the temperatures above the melting point of the main material were summed. The sum of the temperatures is shown in Table II below. Next, the molten material was poured into a mold that had been preheated to 150°C. The mold used was a rectangular prism with internal dimensions of 8mm (length) x 360mm (width) x 11mm (height). After pouring the molten material into the mold, it was left to stand for 5 minutes, and then cooled at a rate of 8°C / min. This resulted in obtaining 100 solid lubricants 1, each with a rectangular prism shape measuring 8 mm in length, 360 mm in width, and 11 mm in height.

[0072] <Manufacturing of solid lubricants 2-9> Solid lubricants 2 to 9 were obtained in the same manner as in the production of solid lubricant 1, except that the types and amounts of main and auxiliary materials, melting temperature and melting time, standing time after pouring into the mold, and cooling rate were changed as shown in Table II below.

[0073] [Table 2]

[0074] [evaluation] <Amount of material removed> A solid lubricant manufactured by Konica Minolta, Inc. was loaded into a full-color printing press (Accurio PRESS C14000). Under conditions of 23°C and 50% RH, 200,000 sheets were continuously printed at 10% coverage using A4 feed. The difference in mass of the solid lubricant before and after printing was defined as the amount of material removed. The amount of wear was measured for 100 solid lubricant tubes, and the average amount of wear from these 100 tubes was calculated. The calculated average amount of wear was evaluated according to the following criteria. (standard) Rank A: Average amount of material removed is less than 1.0g (no practical problems) Rank B: Average amount of material removed is between 1.0g and 2.0g (no practical problems) Rank C: Average amount of material removed is between 2.0g and 3.0g (impairs practical use) Rank D: Average amount of material removed is 3.0g or more (impairs practical use)

[0075] <Variation in the amount of material removed> A solid lubricant manufactured by Konica Minolta, Inc. was loaded into a full-color printing press (Accurio PRESS C14000). 200,000 sheets were continuously printed at 10% coverage using A4 feed under conditions of 23°C and 50% RH. The mass of the solid lubricant was measured before and after printing, and the wear variation (σ) was calculated from the wear amount of 100 samples. The wear variation (σ) can be calculated using the following formula.

number

[0076] <Moldability> When 100 solid lubricants were manufactured, defects such as chipping, cracking, and splitting were visually observed, and the moldability of the defective units was evaluated according to the following criteria. (standard) Rank A: 5 or fewer defective units (no practical problems) Rank B: 6-10 units had defects (no practical problems). Rank C: 11-20 units had defects (no practical problems). Rank D: 21 or more units had defects (implicable issues).

[0077] [Table 3]

[0078] As shown in the results above, when the method for producing solid lubricants of the present invention was used, the amount of abrasion was less, the variation in the amount of abrasion was also less, and the moldability was good compared to the comparative example. [Explanation of Symbols]

[0079] 1. Image forming apparatus 30 Image Processing Unit 40 Image forming unit 41, 41Y, 41M, 41C, 41K Image Forming Units 42 Intermediate Transfer Unit 43 Secondary Transfer Unit 50 Paper transport section 51 Paper feed section 51a, 51b, 51c Paper feed tray unit 52 Paper output section 52a Paper output roller 53 Conveyor Route Section 53a Resist Roller 60 Fixing device 62 Fixing Roller 63. Heated belt 64 Pressure Rollers 110 Image reading unit 111 Paper feeder 112 Scanners 112a CCD sensor 411 (411Y) Exposure System 412(412Y) Developing device 413 (413Y) Photoconductor Drum 414 (414Y) Charging Device 415 (415Y) Cleaning device 415A Cleaning container 415B Cleaning Blade 416 Lubricant application means 416A Rotary Brush 416B Solid Lubricant 416C Biasing member 421 Intermediate transfer belt 422 Primary Transfer Roller 423, 431 Support rollers 423A Backup Roller 426 Belt cleaning device 431A Secondary Transfer Roller 432 Secondary Transfer Belt D Manuscript S paper

Claims

1. A method for manufacturing a solid lubricant to be applied to the surface of an image carrier in an image forming apparatus in an electrophotographic system to form a film on the surface of the image carrier, The solid lubricant contains a higher fatty acid metal salt as the main component and a higher fatty acid metal salt as the secondary component, The process (I) involves heating and melting the main component, the higher fatty acid metal salt, and the auxiliary component, the higher fatty acid metal salt, to form a molten product. The process includes (II) cooling the molten material to obtain the solid lubricant, In steps (I) and (II) described above, the sum of the temperatures of the molten material obtained every second that are equal to or greater than the melting point of the main component, the higher fatty acid metal salt, is 700,000°C or less. A method for producing a solid lubricant, characterized by the following:

2. The main component is the higher fatty acid metal salt, which is zinc stearate. A method for producing a solid lubricant according to feature 1.

3. In steps (I) and (II) described above, the sum of the temperatures of the molten material obtained every second that are equal to or greater than the melting point of the main component, the higher fatty acid metal salt, is 300,000°C or less. A method for producing a solid lubricant according to feature 1.

4. The melting point of the aforementioned auxiliary material, the higher fatty acid metal salt, is in the range of 80 to 230°C. A method for producing a solid lubricant according to feature 1.

5. The metal content of the secondary material, the higher fatty acid metal salt, is within the range of 0.25 to 5% by mass in terms of metal, relative to the metal content of the main material, the higher fatty acid metal salt. A method for producing a solid lubricant according to any one of claims 1 to 4.

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