JP2011095315A - Image forming apparatus and adjusting method for amount of lubricant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus supplying a lubricant to the intermediate transfer body of a copying machine, a facsimile and a printer or the like through a transfer member and securing the amount of lubricant on the intermediate transfer body when a reference toner image is carried, and to provide an adjusting method for the amount of lubricant. <P>SOLUTION: The image forming apparatus uses: the transfer member 65 for transferring the toner image on the intermediate transfer body 11 to a recording medium S passing between itself and the intermediate transfer body 11; a lubricant supplying means 81 for supplying the lubricant 82 to the intermediate transfer body 11 through the transfer member 65 by supplying the lubricant 82 to the transfer member 65; and a recording medium passing mode control means 91 for controlling the passing mode of the recording medium S between 57 the intermediate transfer body 11 and the transfer member 65 so that the amount of lubricant on the intermediate transfer body 11 is increased in a portion carrying the reference toner image. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, or a printer, and an image forming apparatus provided with an intermediate transfer body and a lubricant supply means, and lubrication for adjusting the amount of lubricant on the intermediate transfer body in such an image forming apparatus. The present invention relates to an agent adjustment method.

  In image forming apparatuses such as copiers, facsimiles, printers, etc. (see, for example, [Patent Document 1] to [Patent Document 14] and Japanese Patent Application No. 2009-029686, the prior application of the present applicant) There are image forming apparatuses provided with an intermediate transfer body such as an intermediate transfer belt for intermediately transferring a toner image formed on the body (for example, [Patent Document 2] to [Patent Document 14] and the present applicant). (See Japanese Patent Application No. 2009-029686).

  In such an image forming apparatus, in accordance with the rotation of the photoconductor, a charging process, an exposure process, and a development process are performed on the photoconductor to form a toner image on the photoconductor, and further, a transfer process is performed. The toner image is intermediately transferred to the intermediate transfer member, and the toner image on the intermediate transfer member is further transferred to another medium such as a recording medium such as transfer paper to form an image. Yes.

  After these transfer steps, residual toner remaining on the image carrier such as a photoconductor and an intermediate transfer member, and other foreign matters such as paper dust are removed through a cleaning process by a cleaning means.

  As a cleaning method generally used in the cleaning process, a cleaning blade such as a rubber blade that is inexpensive, has a simple mechanism, and is excellent in cleaning properties is used. It is known to remove.

  However, due to recent demands for higher image quality and the like, spheroidization with polymerized toner and reduction in toner particle size have progressed, and it has become increasingly difficult to clean the toner remaining on the image carrier.

  That is, in order to meet the demand for higher image quality, recently, polymerized toner has been used as a toner used for image formation. For example, SPR-C toner, which is one of polymerized toners, contains Since the wax component is uniformly dispersed inside the toner, there is little precipitation of the wax component to the outside when adhering to the image carrier, and the coefficient of friction of the image carrier surface tends to increase over time. Be looked at. As the coefficient of friction increases, the cleaning performance decreases.

  In recent years, in order to meet the demand for higher image quality, the toner used for image formation has become a small particle size. However, in an image forming apparatus using a small particle size toner, residual toner is The rate at which the cleaning blade and brush roller pass through increases, especially when the dimensional accuracy and assembly accuracy of the cleaning blade and brush roller are insufficient, or when the cleaning blade partially oscillates, As a result, the cleaning performance deteriorates.

  Further, in the method using the cleaning blade, the cleaning blade is pressed against the image carrier to remove residual toner and the like on the surface of the image carrier, so that stress due to friction between the image carrier surface and the cleaning blade is applied. Largely, the cleaning blade and the image carrier are worn, and their life is shortened. Further, when the friction coefficient increases as described above, there arises a problem that the cleaning blade is caught, and in the worst case, the machine is stopped or cannot be restored.

  Therefore, in order to extend the life of the image carrier and maintain high image quality over a long period of time, it is necessary to reduce the deterioration of members such as the image carrier and the cleaning blade due to friction and improve the cleaning performance. Further, filming caused by the toner adhering to the surface of the image carrier due to the contact of the cleaning blade is also a factor of deterioration in image quality, and needs to be prevented.

  Therefore, in recent image forming apparatuses, a technique for applying a lubricant to an image carrier (for example, [Patent Document 3] to [Patent Document 14] and Japanese Patent Application No. 2009-029686, which is an earlier application of the present applicant). No.) has been adopted. According to this technique, it is possible to improve the cleaning performance and prevent filming by forming a lubricant film.

  Among such techniques, there is a technique for supplying a lubricant directly to an intermediate transfer member (see, for example, [Patent Document 9] to [Patent Document 12] and Japanese Patent Application No. 2009-029686, which is a prior application of the present applicant). is there. However, in this technique, the amount of lubricant applied becomes unstable due to the toner on the intermediate transfer member adhering to a member that contacts the intermediate transfer member in order to supply the lubricant, There is a problem in that the lubricant supplied to the intermediate transfer member adheres to the photosensitive member and causes a problem with the photosensitive member.

  On the other hand, a technique for supplying a lubricant to a transfer member abutting on the intermediate transfer member to perform secondary transfer and indirectly supplying the lubricant to the intermediate transfer member via the transfer member (for example, [Patent Document 11] ] To [Patent Document 14]), and this technique can avoid such a problem.

Among the techniques for applying a lubricant to an image carrier (see, for example, [Patent Document 3] to [Patent Document 14] and Japanese Patent Application No. 2009-029686, the prior application of the present applicant) (See, for example, [Patent Document 3] to [Patent Document 9], [Patent Document 11], [Patent Document 12]), and a contact portion of a cleaning blade with an image carrier as a lubricant. In which a dam effect for rapidly forming a nip is obtained and a fatty acid metal salt excellent in film-forming properties (for example, [Patent Document 3] to [Patent Document 5], [Patent Document 13] And Japanese Patent Application No. 2009-029686, which is a prior application of the present applicant, and a technique for controlling the amount of lubricant supplied (for example, [Patent Document 6], [Patent Document 7], [Patent Document 9] to [Patent Document 9] to [Patent Document 9] to [Patent Document 9] Patent Document 11] and the prior application of the present applicant There is a reference Japanese Patent Application No. 2009-029686).
In addition, an image for so-called process control is formed in which a reference toner image having a predetermined pixel pattern is formed at a predetermined timing and good image formation is maintained based on the detection result of the toner amount constituting the reference toner image. A forming apparatus is known (see, for example, [Patent Document 1] and [Patent Document 14]).

  However, in the technique of supplying the lubricant indirectly to the intermediate transfer member via the transfer member (for example, see [Patent Document 11] to [Patent Document 14]), the lubricant is interposed between the intermediate transfer member and the transfer member. When passing the recording medium, the lubricant adhering to the intermediate transfer member and the transfer member is taken away by the recording medium, and the supply of the lubricant from the transfer member to the intermediate transfer member is stopped. The application efficiency of the lubricant is not necessarily high.

  Therefore, when performing process control, particularly when performing process control after a recording medium has passed continuously between the intermediate transfer member and the transfer member, such as by forming a large number of images, it is normal. Since the toner constituting the reference toner is carried on the intermediate transfer body in a larger amount than the amount of toner remaining on the intermediate transfer body during image formation, the amount of lubricant on the intermediate transfer body is intermediate transfer. This is less than the amount necessary for cleaning the body, which may interfere with the cleaning of the intermediate transfer body.

  The present invention relates to an image forming apparatus for supplying a lubricant to an intermediate transfer member via a transfer member, such as a copying machine, a facsimile machine, and a printer, and the amount of lubricant on the intermediate transfer member when a reference toner image is carried An object of the present invention is to provide an image forming apparatus and a lubricant adjusting method for ensuring the above.

  In order to achieve the above object, the invention according to claim 1 is directed to a transfer member for enabling a toner image on the intermediate transfer member to be transferred to a recording medium passing between the intermediate transfer member and a lubricant for the transfer member. A lubricant supplying means for supplying a lubricant to the intermediate transfer member through the transfer member by supplying an agent, and a mode of passage of the recording medium between the intermediate transfer member and the transfer member. And an image forming apparatus having a recording medium passage mode control means for controlling the amount of lubricant on the intermediate transfer member to increase at the portion carrying the toner.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the recording medium passage mode control unit causes the intermediate transfer body to be idled until the passage mode carries the reference toner image. By doing so, the amount of lubricant on the intermediate transfer member at the portion carrying the reference toner image is increased.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the image forming apparatus further comprises a transfer member rotation speed control means for increasing the rotation speed of the transfer member in the state.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the recording medium passage mode control means is configured such that the passage mode is between the intermediate transfer member and the transfer member. The amount of lubricant on the intermediate transfer member is increased at the portion where the reference toner image is carried by increasing the interval between the recording media passing through the toner.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the recording medium passage mode control means is configured such that the passage mode is between the intermediate transfer member and the transfer member. By changing the state of the recording medium so that the width of the recording medium passing through the toner is reduced, the amount of the lubricant on the intermediate transfer member at the portion carrying the reference toner image is increased.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the intermediate transfer member on the intermediate transfer member from a position where the intermediate transfer member carries the reference toner image in the moving direction of the intermediate transfer member. Reference toner image detection means for detecting a reference toner image on the intermediate transfer member is provided until the toner image is transferred to the recording medium by the transfer member. It is characterized in that it is in contact with the intermediate transfer member in a state where an image is carried.

  According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the intermediate transfer member carries a reference toner image in a passable area of the recording medium in the width direction. The lubricant applying means supplies the lubricant to the transfer member in a width direction of the intermediate transfer body corresponding to a region where the intermediate transfer body carries a reference toner image.

  According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the lubricant includes an inorganic lubricant, and the inorganic lubricant includes boron nitride.

  According to the ninth aspect of the present invention, the transfer member for transferring the toner image on the intermediate transfer member to a recording medium passing between the intermediate transfer member and the lubricant is supplied to the transfer member. The lubricant supply means for supplying the lubricant to the intermediate transfer member via the transfer member, and the passage mode of the recording medium between the intermediate transfer member and the transfer member, the intermediate transfer at the portion carrying the reference toner image The lubricant amount adjustment method adjusts the amount of lubricant on the intermediate transfer body using a recording medium passage mode control means for controlling the amount of lubricant on the body to increase.

  The present invention provides a transfer member for enabling transfer of a toner image on an intermediate transfer member to a recording medium passing between the intermediate transfer member and a lubricant supplied to the transfer member, thereby passing the transfer member through the transfer member. The lubricant supply means for supplying the lubricant to the intermediate transfer member, and the mode of passage of the recording medium between the intermediate transfer member and the transfer member, the lubrication on the intermediate transfer member at the portion carrying the reference toner image Since the image forming apparatus has a recording medium passage mode control unit that controls the amount of the agent to increase, the amount of lubricant on the intermediate transfer member when the reference toner image is carried can be secured, and the intermediate transfer An image forming apparatus capable of forming a state in which the body is satisfactorily cleaned and capable of forming a good image over time can be provided.

  The recording medium passage mode control means sets the passage mode to a state where the intermediate transfer member is idle until the reference toner image is carried, so that the portion on the intermediate transfer member carrying the reference toner image is placed. If the amount of lubricant is increased, the amount of lubricant on the intermediate transfer member when the reference toner image is carried can be ensured by idling the intermediate transfer member, and the intermediate transfer member can be cleaned well. Thus, it is possible to provide an image forming apparatus capable of forming a state to be performed, and thereby performing good image formation over time.

  If there is a transfer member rotation speed control means for increasing the rotation speed of the transfer member in the state, the intermediate transfer member is idled and the rotation speed of the transfer member is increased to carry the reference toner image. The amount of lubricant on the intermediate transfer member can be better ensured, and it is possible to form a state in which the intermediate transfer member is satisfactorily cleaned, thereby forming a good image over time. A possible image forming apparatus can be provided.

  The recording medium passage mode control means is configured to increase the interval of the recording medium passing between the intermediate transfer member and the transfer member so that the intermediate transfer at the portion carrying the reference toner image is performed. If the amount of lubricant on the body is increased, the amount of lubricant on the intermediate transfer member when the reference toner image is carried can be ensured by increasing the interval of the recording medium. It is possible to provide an image forming apparatus capable of forming a state in which cleaning is performed satisfactorily, and thereby performing good image formation over time.

  The recording medium passage mode control means changes the position of the recording medium so that the width of the recording medium passing between the intermediate transfer member and the transfer member is reduced. If the amount of lubricant on the intermediate transfer member is increased at the portion where the toner image is carried, the intermediate transfer in the case where the reference toner image is carried by changing the position of the recording medium so that the width is reduced. Image forming apparatus capable of ensuring the amount of lubricant on the body and capable of forming a state in which the intermediate transfer member can be satisfactorily cleaned, thereby forming a good image over time Can be provided.

  The reference toner on the intermediate transfer member from the position where the intermediate transfer member carries the reference toner image in the moving direction of the intermediate transfer member to the position where the toner image on the intermediate transfer member is transferred to the recording medium by the transfer member. Reference toner image detection means for detecting an image, and the transfer member disturbs the reference toner image if the intermediate transfer member is in contact with the intermediate transfer member while carrying the reference toner image. And the amount of lubricant on the intermediate transfer body when the reference toner image is carried can be ensured, and a state in which the intermediate transfer body is satisfactorily cleaned can be formed. Thus, it is possible to provide an image forming apparatus capable of performing good image formation over time.

  The intermediate transfer member carries a reference toner image in a region in which the recording medium can pass in the width direction, and the lubricant applying means is a region in which the intermediate transfer member carries a reference toner image in the width direction of the intermediate transfer member. If the lubricant is supplied to the transfer member correspondingly, the amount of lubricant on the intermediate transfer member when the reference toner image is carried while using the minimum lubricant can be secured. An image forming apparatus capable of forming a state in which the transfer member is satisfactorily cleaned and capable of forming a good image over time can be provided.

  If the lubricant contains an inorganic lubricant, and this inorganic lubricant contains boron nitride, the amount of lubricant on the intermediate transfer member when the reference toner image is carried can be ensured. By the action, it is possible to form a state in which the intermediate transfer member is more satisfactorily cleaned, and thus it is possible to provide an image forming apparatus capable of performing good image formation over time.

  The present invention provides a transfer member for enabling transfer of a toner image on an intermediate transfer member to a recording medium passing between the intermediate transfer member and a lubricant supplied to the transfer member, thereby passing the transfer member through the transfer member. The lubricant supply means for supplying the lubricant to the intermediate transfer member, and the mode of passage of the recording medium between the intermediate transfer member and the transfer member, the lubrication on the intermediate transfer member at the portion carrying the reference toner image In the method for adjusting the amount of lubricant on the intermediate transfer member using the recording medium passage mode control means for controlling the amount of agent to increase, the intermediate transfer member in the case of carrying a reference toner image The amount of lubricant above can be ensured, and it is possible to form a state where the intermediate transfer member is satisfactorily cleaned, which contributes to enabling good image formation over time. Do It is possible to provide a lubricant amount adjustment method.

1 is a schematic front view of an image forming apparatus to which the present invention is applied. FIG. 10 is a schematic front view showing a modification of the secondary transfer device provided in the image forming apparatus shown in FIG. 1. FIG. 5 is a correlation diagram illustrating a correlation between a lubricant component and cleaning performance. It is the schematic for demonstrating that an indirect application method can reduce an apparatus size rather than a direct application method, Comprising: (a) employs the indirect application method which applied this invention shown in FIG. FIG. 6 is a schematic front view showing a part of a modified example of the image forming apparatus, and FIG. 5B is a schematic front view showing a configuration corresponding to the configuration shown in FIG. In the image forming apparatus shown in FIG. 1, a partially broken schematic plan view for explaining control for increasing the amount of lubricant on the intermediate transfer member at a portion carrying the reference toner image by reducing the width of the recording medium. It is. FIG. 2 is a schematic plan view illustrating a configuration example in which a lubricant is supplied to a transfer member corresponding to a region where an intermediate transfer member carries a reference toner image in the image forming apparatus illustrated in FIG. 1. It is a schematic front view for demonstrating the malfunction in the case of employ | adopting a direct application | coating system.

  FIG. 1 shows an outline of an image forming apparatus to which the present invention is applied. The image forming apparatus 100 is a color laser printer, but may be other types of image forming apparatuses such as other types of printers, facsimile machines, copiers, and multifunction machines of copiers and printers. The image forming apparatus 100 performs an image forming process based on an image signal corresponding to image information received from the outside. The image forming apparatus 100 can form an image using plain paper generally used for copying, OHP sheets, thick paper such as cards and postcards, and envelopes as sheet-like recording media. .

  The image forming apparatus 100 is a photoconductor that is a latent image carrier as a first image carrier that can form an image as an image corresponding to each color separated into yellow, magenta, cyan, and black. A tandem structure in which the photosensitive drums 20Y, 20M, 20C, and 20BK are arranged in parallel, in other words, a tandem system is adopted.

  The photosensitive drums 20Y, 20M, 20C, and 20BK that are surface moving members are rotatably supported by a frame (not shown) of the main body 99 of the image forming apparatus 100, and are endless belts that are intermediate transfer members as a second image carrier. The transfer belts 11 are arranged in this order from the upstream side of the A1 direction which is the moving direction of the transfer belt 11 and is the counterclockwise direction in FIG. Y, M, C, and BK added after the numerals of the respective symbols indicate members for yellow, magenta, cyan, and black.

  Each of the photosensitive drums 20Y, 20M, 20C, and 20BK has image forming units 60Y, 60M, 60C, and 60BK for forming yellow (Y), magenta (M), cyan (C), and black (BK) images, respectively. Is provided.

  The photoconductive drums 20Y, 20M, 20C, and 20BK are positioned on the outer peripheral surface side of the transfer belt 11 that is configured as an endless belt disposed substantially at the center inside the main body 99, that is, on the image forming surface side.

  The transfer belt 11 is movable in the direction of the arrow A1 while facing the photosensitive drums 20Y, 20M, 20C, and 20BK. Visible images, that is, toner images formed on the respective photosensitive drums 20Y, 20M, 20C, and 20BK are respectively superimposed and transferred onto the transfer belt 11 that moves in the direction of the arrow A1, and then collectively onto the transfer sheet S that is a recording medium. It is designed to be transcribed. Therefore, the image forming apparatus 100 is an intermediate transfer type, in other words, an indirect transfer type image forming apparatus. Therefore, the image forming apparatus 100 is a tandem indirect transfer type image forming apparatus.

  The lower portion of the transfer belt 11 faces the photosensitive drums 20Y, 20M, 20C, and 20BK, and the opposed portions transfer the toner images on the photosensitive drums 20Y, 20M, 20C, and 20BK. A primary transfer portion 58 for transferring to the transfer belt 11 is formed.

  In the superimposing transfer to the transfer belt 11, the toner images formed on the photosensitive drums 20Y, 20M, 20C, and 20BK are transferred to the same position on the transfer belt 11 while the transfer belt 11 moves in the A1 direction. As described above, voltage application by the primary transfer rollers 12Y, 12M, 12C, and 12BK disposed at positions facing the photosensitive drums 20Y, 20M, 20C, and 20BK across the transfer belt 11 causes the A1 direction upstream. The timing is shifted toward the downstream side.

  The transfer belt 11 has a multilayer structure in which the base layer is made of a material with little elongation, the surface of the base layer is covered with a smooth material, and the coat layer is formed on the base layer. Examples of the material of the base layer include a fluororesin, a PVDF sheet, and a polyimide resin. Examples of the material of the coat layer include a fluorine resin.

  Each of the transfer belts 11 has a detent guide (not shown) as a detent member at each edge thereof. The detent guide is arranged to prevent the transfer belt 11 from being biased in any of the width directions perpendicular to the paper surface in FIG. 1 corresponding to the main scanning direction when the transfer belt 11 rotates in the A1 direction. It is installed. The stopper guide is made of urethane rubber, but can be made of various rubber materials such as silicon rubber.

  The transfer belt 11 has a width corresponding to the A4-sized transfer sheet S in the width direction. Therefore, the image forming apparatus 100 can form an image on the transfer sheet S of A4 horizontal size at the maximum.

  The image forming apparatus 100 is disposed in the main body 99 so as to oppose the four image forming units 60Y, 60M, 60C, and 60BK and the respective photosensitive drums 20Y, 20M, 20C, and 20BK. A transfer belt unit 10 as an intermediate transfer unit provided, a secondary transfer device 5 disposed on the right side of the transfer belt 11 in FIG. 1 so as to face the transfer belt 11, and image forming units 60Y, 60M, 60C, 60BK. And an optical scanning device 8 serving as an exposure device, which is an optical writing unit as a latent image forming means disposed facing the lower side.

  The image forming apparatus 100 also serves as a paper feed cassette capable of stacking a large number of transfer sheets S conveyed toward the secondary transfer unit 57 between the transfer belt 11 and the secondary transfer apparatus 5 in the main body 99. The sheet transfer device 61 and the recording sheet S conveyed from the sheet supply device 61 are transferred at a predetermined timing in accordance with the toner image formation timing by the image forming units 60Y, 60M, 60C, and 60BK. A registration roller pair 4 that is fed out toward the registration roller 57 and a sensor (not shown) that detects that the leading edge of the transfer sheet S has reached the registration roller pair 4 are provided.

  The image forming apparatus 100 also includes a fixing device 6 as a roller fixing type fixing unit for fixing the toner image on the transfer sheet S to which the toner image is transferred, and a fixed transfer sheet S in the main body 99. A discharge roller 7 as a discharge roller pair that is a discharge roller that discharges to the outside of the main body 99, and a toner that is disposed above the transfer belt unit 10 and is filled with toners of yellow, cyan, magenta, and black. It has bottles 9Y, 9M, 9C, and 9BK, and a paper discharge tray 17 that is disposed above the main body 99 and on which the transfer paper S discharged from the main body 99 by the discharge roller 7 is stacked.

  The image forming apparatus 100 is also disposed opposite to the transfer belt 11 at a position upstream of the secondary transfer unit 57 and downstream of the primary transfer unit 58 in the A1 direction, and the image forming unit 60BK during process control to be described later. A toner sensor 90 as a reference toner image detecting means for detecting a reference toner image as a toner pattern as a reference pattern as an image adjustment pattern of each color formed in 60Y, 60M and 60C and transferred onto the transfer belt 11, and each photoconductor A driving device (not shown) that rotationally drives the drums 20Y, 20M, 20C, and 20BK, and a control unit 91 that includes a CPU (not shown), a memory, and the like that control the overall operation of the image forming apparatus 100 are provided.

  In addition to the transfer belt 11, the transfer belt unit 10 includes primary transfer rollers 12Y, 12M, 12C, and 12BK as primary transfer bias rollers, and a drive roller 72 that is a drive member around which the transfer belt 11 is wound. A counter roller 74 as a stretching roller, tension rollers 75 and 33 as support rollers for stretching the transfer belt 11 together with the driving roller 72 and the cleaning roller 74, and the transfer belt 11. And a cleaning device 13 as a belt cleaning device which is an intermediate transfer member cleaning device for cleaning the surface of the transfer belt 11.

  The transfer belt unit 10 also includes a drive system (not shown) that includes a drive motor (not shown) that rotationally drives the drive roller 72, and a bias application (not shown) that applies a primary transfer bias to the primary transfer rollers 12Y, 12M, 12C, and 12BK. And a power source and bias control means.

  The driving roller 72, the cleaning facing roller 74, and the stretching rollers 75 and 33 are support rollers that are wound around the transfer belt 11 so as to be able to be rotated and conveyed. The cleaning facing roller 74 and the stretching rollers 75 and 33 are driven rollers that rotate with the transfer belt 11 that is rotationally driven by the driving roller 72. The primary transfer rollers 12Y, 12M, 12C, and 12BK press the transfer belt 11 from the back surface thereof toward the photosensitive drums 20Y, 20M, 20C, and 20BK to form primary transfer nips. The primary transfer nip is formed at a portion of the transfer belt 11 that is stretched between the stretching rollers 75 and 33. The tension rollers 75 and 33 have a function of stabilizing the primary transfer nip.

  In each primary transfer nip, a primary transfer electric field is formed between the photosensitive drums 20Y, 20M, 20C, and 20BK and the primary transfer rollers 12Y, 12M, 12C, and 12BK due to the influence of the primary transfer bias. . The toner images of the respective colors formed on the photosensitive drums 20Y, 20M, 20C, and 20BK are primarily transferred onto the transfer belt 11 due to the influence of the primary transfer electric field and nip pressure.

The tension roller 33 is brought into contact with the secondary transfer device 5 via the transfer belt 11 to form a secondary transfer portion 57. Therefore, the stretching roller 33 also serves as a secondary transfer counter roller.
The cleaning counter roller 74 has a function as a tension roller as a pressure member that gives the transfer belt 11 a predetermined tension suitable for transfer.

  The life of the transfer belt 11 is substantially an integral multiple of the life of the photosensitive drums 20Y, 20M, 20C, and 20BK. When replacing the transfer belt 11 due to the life of the transfer belt 11, if the photoreceptor drums 20Y, 20M, 20C, and 20BK have also reached the end of their lives, the photoreceptor drums 20Y, 20M, 20C, and 20BK are also replaced. As described above, the transfer belt 11 and the photosensitive drums 20Y, 20M, 20C, and 20BK are replaced at the same time by setting the lifetime of the transfer belt 11 to be approximately an integral multiple of the lifetime of the photosensitive drums 20Y, 20M, 20C, and 20BK. In addition to improving maintainability, the transfer due to an increase in the friction coefficient of the photosensitive drums 20Y, 20M, 20C, and 20BK when the photosensitive drums 20Y, 20M, 20C, and 20BK that have reached the end of their life are left unattended. The reduction in the rate and the occurrence of a hollow image are suppressed or prevented.

  However, even if the life of the transfer belt 11 is not substantially an integral multiple of the life of the photosensitive drums 20Y, 20M, 20C, and 20BK, when the transfer belt 11 is replaced due to the life of the transfer belt 11, the photosensitive drums 20Y, 20M, and 20C are replaced. If the photoconductor drums 20Y, 20M, 20C, and 20BK are also replaced when 20BK has reached the end of its life, or is approaching the end of its life, the maintenance performance is improved and the transfer rate is lowered. There is an advantage that the occurrence of a hollow image is suppressed or prevented.

  The cleaning device 13 is disposed to the left of the cleaning facing roller 74 and the stretching roller 75 in FIG. The cleaning device 13 is disposed so as to contact the transfer belt 11 at a position facing the cleaning counter roller 74, that is, at a position downstream of the secondary transfer portion 57 and upstream of the primary transfer portion 58 in the A1 direction. The cleaning blade 76 and a case 77 in which the cleaning blade 76 is housed.

  The cleaning device 13 cleans the transfer belt 11 by scraping and removing foreign matters such as residual toner on the transfer belt 11 with a cleaning blade 76. The cleaning device 13 also cleans a reference toner image that is a reference pattern of each color formed in the image forming units 60BK, 60Y, 60M, and 60C and transferred onto the transfer belt 11 during process control described later.

  The sheet feeding device 61 accommodates a plurality of transfer paper S in a state where a plurality of transfer papers S are stacked. The sheet feeding device 61 is arranged below the optical scanning device 8 at the lower part of the main body 99 in multiple stages, in this embodiment, in two stages. ing. A paper bank 31 serving as a paper feed table is formed at the bottom of the main body 99 by the multistage sheet feeding device 61. In this embodiment, it is assumed that the upper sheet feeding device 61 accommodates A4 horizontal size transfer paper S and the lower sheet feeding device 61 accommodates A4 vertical size transfer paper S.

The sheet feeding device 61 has a feeding roller 3 as a sheet feeding roller pressed against the upper surface of the uppermost transfer sheet S, and the feeding roller 3 is driven to rotate counterclockwise at a predetermined timing. Thus, the uppermost transfer sheet S is separated one by one and fed toward the registration roller pair 4. In this respect, the paper feed roller 3 also functions as a separation roller.
The transfer sheet S delivered from the sheet feeding device 61 reaches the registration roller pair 4 through the sheet feeding path 32 and is sandwiched between the rollers of the registration roller pair 4.

  The secondary transfer device 5 is disposed to face the stretching roller 33. The secondary transfer device 5 includes a secondary transfer belt 65 that is an endless belt disposed so as to sandwich the transfer belt 11 with the stretching roller 33, a drive roller 67 that spans the secondary transfer belt 65, and a follower. A roller 66, 68, 69, a lubricant application device 81 serving as a lubricant application unit disposed opposite to the secondary transfer belt 65 at a position facing the roller 66, and secondary transfer It has a cleaning device 64 that cleans the belt 65 and drive means as a drive system including a motor (not shown) that drives the drive roller 67 to rotate. The operation of the driving unit is controlled by the control unit 91, and the secondary transfer belt 65 is rotationally driven in the direction of the arrow in FIG. 1 by the rotation of the roller 67 and the driven rotation of the rollers 66, 68, 69. In this respect, the control unit 91 functions as a transfer member drive control unit.

  The secondary transfer belt 65 is pressed against the stretching roller 33 via the transfer belt 11 at the portion stretched between the rollers 68 and 69, and the toner image on the transfer belt 11 is transferred onto the transfer paper S at this portion. It is supposed to be transferred to. Therefore, the secondary transfer belt 65 functions as a transfer member that is a secondary transfer member for enabling transfer of the toner image on the transfer belt 11 to the transfer sheet S passing between the transfer belt 11 and the transfer belt 11.

  The secondary transfer device 5 also has a sheet conveying function for conveying the transfer paper S after the toner image is transferred to the fixing device 6. As the secondary transfer device 5, a transfer roller 70 that is a secondary transfer roller as a transfer member shown in FIG. 2 may be used. However, the sheet conveyance for conveying the transfer sheet S after image transfer to the fixing device 6 is possible. The secondary transfer device 5 of the type shown in FIG. 1 is preferable in that it has a function. When the transfer roller 70 shown in FIG. 2 is used, the drive roller 72 also serves as a secondary transfer counter roller.

  The cleaning device 64 cleans the secondary transfer belt 65 by removing foreign matters such as paper dust and toner adhering to the secondary transfer belt 65 at a portion facing the roller 67.

The lubricant application device 81 supplies the lubricant to the transfer belt 11 through the secondary transfer belt 65 by supplying the lubricant to the secondary transfer belt 65.
Details of the lubricant application device 81 will be described later.

  The fixing device 6 is disposed above the secondary transfer device 5. The fixing device 6 includes a heating roller 62 as a fixing roller having a heat source therein, and a pressure roller 63 pressed against and in pressure contact with the heating roller 62.

  The fixing device 6 passes the transfer paper S carrying the toner image in a manner to sandwich the fixing paper, which is a pressure contact portion between the heating roller 62 and the pressure roller 63, so that the toner image carried by the heat and pressure is applied. Is fixed to the surface of the transfer paper S.

  The yellow, cyan, magenta, and black toners in the toner bottles 9Y, 9M, 9C, and 9BK are polymerized toners in which the wax component is uniformly dispersed therein. Less precipitation to the outside. The toner of each color is supplied to the developing devices 80Y, 80M, 80C, and 80BK provided in the image forming units 60Y, 60M, 60C, and 60BK by a predetermined supply amount through a conveyance path (not shown).

  The toner sensor 90 is a primary transfer that is a position at which a reference toner image, which is a reference pattern of each color formed in the image forming units 60BK, 60Y, 60M, and 60C during process control, which will be described later, is transferred and carried on the transfer belt 11. A secondary transfer portion that is a position where a toner image on the transfer belt 11 formed on the transfer belt 11 formed during normal image formation from the portion 58 is transferred to the transfer paper S by the secondary transfer belt 65. Reference toner images on the transfer belt 11 are detected at positions up to 57.

  The image forming units 60Y, 60M, 60C, and 60BK have the same configuration. The image forming units 60Y, 60M, 60C, and 60BK are respectively arranged around the photosensitive drums 20Y, 20M, 20C, and 20BK along the rotation direction B1, which is the clockwise direction in FIG. 12C, 12BK, cleaning devices 71Y, 71M, 71C, 71BK as cleaning means, static elimination devices 78Y, 78M, 78C, 78BK as static elimination means, and charging devices 79Y, 79M, 79C as charging means for performing AC charging 79BK, developing devices 80Y, 80M, 80C, 80BK as developing means for performing development with a two-component developer, and a lubricant coating device (not shown) having the same configuration as the lubricant coating device 81. Note that the lubricant application device is located between the cleaning devices 71Y, 71M, 71C, and 71BK and the charge eliminating devices 78Y, 78M, 78C, and 78BK in the B1 direction.

  In the image forming apparatus 100 having such a configuration, when a signal indicating that a color image should be formed is input, the driving roller 72 is driven, and the transfer belt 11, the cleaning facing roller 74, and the stretching rollers 75 and 33 are driven. At the same time, the photosensitive drums 20Y, 20M, 20C, and 20BK are driven to rotate in the B1 direction.

  The photosensitive drums 20Y, 20M, 20C, and 20BK are uniformly charged on the surface by the charging devices 79Y, 79M, 79C, and 79BK as the B1 rotates, and the laser beam exposure scanning from the optical scanning device 8 is performed. To form an electrostatic latent image corresponding to each color of yellow, magenta, cyan, and black, and the electrostatic latent image is developed with toners of yellow, magenta, cyan, and black by developing devices 80Y, 80M, 80C, and 80BK. As a result, a single-color image constituted by magenta, cyan, and black toner images is formed.

  The yellow, magenta, cyan, and black toner images obtained by development are sequentially transferred to the same position on the transfer belt 11 rotating in the A1 direction by the primary transfer rollers 12Y, 12M, 12C, and 12BK. As a result, a composite color image is formed on the transfer belt 11.

  On the other hand, when a signal indicating that a color image should be formed is input, one of the sheet feeding devices 61 provided in the paper bank 31 is selected, and a feeding roller provided in the selected sheet feeding device 61 is selected. 3 is rotated to feed out the transfer paper S and separated one by one and fed to the paper feed path 32. The transfer paper S fed into the paper feed path 32 is further conveyed by a conveyance roller (not shown) and hits the registration roller pair 4. Stop in the hit state.

  The registration roller pair 4 rotates in accordance with the timing at which the composite color image superimposed on the transfer belt 11 moves to the secondary transfer unit 57 as the transfer belt 11 rotates in the A1 direction. The composite color image is in close contact with the transfer sheet S sent to the secondary transfer unit 57, and is secondarily transferred and recorded on the transfer sheet S by the action of the nip pressure.

  The transfer paper S is transported by the secondary transfer device 5 and sent to the fixing device 6, and when the fixing device 6 passes through the fixing portion between the heating roller 62 and the pressure roller 63, it is caused by the action of heat and pressure. The carried toner image, that is, the synthesized color image is fixed.

  The transfer sheet S on which the composite color image has been fixed, which has passed through the fixing device 6, is discharged out of the main body 99 through the discharge roller 7 and stacked on the discharge tray 17 at the top of the main body 99.

  Photoreceptor drums 20Y, 20M, 20C, and 20BK remove the transfer residual toner remaining after the transfer by cleaning devices 71Y, 71M, 71C, and 71BK, and are neutralized by static eliminators 78Y, 78M, 78C, and 78BK, and charging devices 79Y, It is subjected to the next charging by 79M, 79C, 79BK.

  The transfer belt 11 that has passed the secondary transfer portion 57 after the secondary transfer is cleaned by removing the transfer residual toner remaining on the surface after the transfer by the cleaning blade 76 provided in the cleaning device 13, and the next transfer. Prepare for.

  On the other hand, in the image forming apparatus 100, in addition to normal image formation designated by the user, image formation of a reference toner image is performed at the time of process control called so-called adjustment operation. The process control corrects changes in image forming performance due to changes in each part of the image forming apparatus 100 over time, and forms toner on the photosensitive drums 20Y, 20M, 20C, and 20BK in order to form a uniform image over time. Conditions for forming an image, in other words, image forming conditions, for example, charging potentials of the photosensitive drums 20Y, 20M, 20C, and 20BK by the charging devices 79Y, 79M, 79C, and 79BK, and developing biases in the developing devices 80Y, 80M, 80C, and 80BK, for example. This is performed to control the developing performance based on the toner density and the like, the intensity of the laser beam in the optical scanning device 8, in other words, the potential of the image forming unit based on the latent image writing intensity.

  The control of the image forming conditions is performed so that, for example, the image density becomes a target image density that is set in advance and stored in the memory of the control unit 91, that is, a target adhesion amount as a reference image density that is a target image density. Is called. This control is performed by the control means 91. In this respect, the control unit 91 functions as an image formation condition control unit and an image formation condition setting unit, and the control unit 91 or the memory functions as a target image density storage unit.

  Further, the process control corrects a change in the formation position of each color toner image by each of the image forming units 60Y, 60M, 60C, and 60BK due to a change in each part of the image forming apparatus 100 over time, and the process control is uniform over time. In order to maintain the image forming position, it is performed to control the timing of forming the toner images of the respective colors by the image forming units 60Y, 60M, 60C, and 60BK.

  The control of the image forming timing is performed by the control unit 91. In this respect, the control unit 91 functions as an image formation position control unit, an image formation timing control unit, an image formation position setting unit, and an image formation timing setting unit.

  The reference toner image of each color is detected when the image forming apparatus 100 is switched to the process control mode when the image forming apparatus 100 is turned on, at the end of a predetermined number of image formations, or the like in order to detect such a change in image forming performance and a change in image forming position In addition, the image forming units 60BK, 60Y, 60M, and 60C are formed at different positions on the transfer belt 11 in the width direction or A1 direction of the transfer belt 11. The control unit 91 counts the number of image formations as a condition for starting process control. Since the transfer belt 11 has a width corresponding to the A4 horizontal size transfer sheet S in the width direction, the reference toner image of each color also has an A4 horizontal size on the transfer belt 11 in the width direction. The transfer paper S is formed in the passage region.

  When the process control is executed, the secondary transfer belt 65 is kept in contact with the transfer belt 11 in the secondary transfer portion 57. This is because the toner sensor 90 is disposed facing the transfer belt 11 at a position between the primary transfer portion 58 and the secondary transfer portion 57 in the A1 direction. Since the secondary transfer belt 65 is in contact with the transfer belt 11, even if the reference toner image is disturbed, detection of the reference toner image by the toner sensor 90 is not affected. ing.

  The toner sensor 90 detects the toner density or toner adhesion amount and position of the reference toner image of each color. Based on this, the control means 91 forms the above-mentioned image forming conditions so as to constitute an image having a good toner density or toner adhesion amount of an image to be formed thereafter, and so that the position of the image occupies a predetermined position. The charging potential of the photosensitive drums 20Y, 20M, 20C, and 20BK by the charging devices 79Y, 79M, 79C, and 79BK, the developing bias in the developing devices 80Y, 80M, 80C, and 80BK, the developing performance by the toner density, and the optical scanning device In other words, the intensity of the laser beam at 8, in other words, adjusts the potential of the image forming unit according to the latent image writing intensity and adjusts the image forming timing.

  The toner sensor 90 functions as a toner concentration detection unit, a toner adhesion amount detection unit, and a toner amount detection unit in that it detects the toner concentration or toner adhesion amount of each color toner image, and the transfer belt 11 of each color toner image. It functions as an image forming position detecting means in that the position on the upper side is detected.

  Here, as described above, conventionally, a cleaning method using a cleaning blade is known as a cleaning method generally used for a cleaning device. However, it has been used in the image forming apparatus 100 due to a recent demand for higher image quality. As is the case with the toners used, the spheroidization by the polymerized toner and the reduction in the particle size of the toner have progressed, and it has become difficult to clean the residual toner remaining on the image carrier. Further, as described above, the toner used in the image forming apparatus 100 is a polymerized toner in which the wax component is uniformly dispersed therein, and when the toner adheres to the transfer belt 11, the wax component is deposited on the outside. Therefore, the friction coefficient on the surface of the transfer belt 11 tends to increase with time.

  In addition, as in the image forming apparatus 100, in the configuration using the cleaning blade in the image carrier cleaning apparatus, stress due to friction between the surface of the image carrier and the cleaning blade is large. There is a problem that the wear of the image carrier occurs and the life of the image carrier is shortened, and the problem that the cleaning blade is involved, so that in order to extend the life of the image carrier and maintain high image quality over a long period of time, It is necessary to reduce the deterioration of members such as the image bearing member and the cleaning blade due to friction and improve the cleaning performance. Filming caused by the toner adhering to the surface of the image bearing member due to the contact of the cleaning blade is also of high image quality. It was necessary to prevent it because it was a factor of decline.

  Therefore, in recent image forming apparatuses, even if the coefficient of friction on the surface of an image carrier such as an intermediate transfer member increases with time due to the nature of the toner, the cleaning blade can be prevented from being caught or filming can be prevented. In order to improve cleaning performance and prevent filming, a technique of applying a lubricant to an image carrier to form a film of the lubricant is employed. The transfer device 5 includes a lubricant application device 81.

  The lubricant application device 81 is in contact with the lubricant material 82 as a lubricant solidified in a columnar shape, the lubricant material 82 and the secondary transfer belt 65, scrapes the lubricant material 82, and is applied to the secondary transfer belt 65. A brush roller 83 that is an application brush as an application member to be supplied and applied, a holding member 84 that holds the lubricating substance 82 and urges the brush roller 83, and a position where the brush roller 83 faces the secondary transfer belt 65. The secondary transfer belt 65 includes a driving unit (not shown) that rotates in the same direction.

The brush roller 83 is disposed so as to extend in the width direction of the secondary transfer belt 65, and is disposed so as to be in sliding contact with the surface of the secondary transfer belt 65 throughout the same direction. The brush material constituting the brush roller 83 is polyester, nylon, etc., 3 to 6 denier, 30 to 120 × 1000 [f / inch ² (f: abbreviation for filament, minimum unit as a fibrous body)] It is.

  The lubricating substance 82 has the same length of the brush roller 83 in the width direction, and is disposed in the same arrangement area as the arrangement area of the brush roller 83 in the same direction. The entire surface of the lubricating material 82 is in contact with the brush roller 83 with a uniform surface pressure due to the urging force of the holding member 84.

  The lubricating material 82 is a material such as a magnetic carrier contained in the developer together with the surfaces of the transfer belt 11 and the secondary transfer belt 65 and the toners and toners of the respective colors contacting the surfaces, or the cleaning blade 76 and the transfer belt 11. The component is a fatty acid metal salt excellent in film formability and is dammed at the contact portion of the cleaning blade 76 with the transfer belt 11 to quickly form a nip. In combination with an inorganic lubricant that provides a dam effect.

  Specifically, examples of fatty acid metal salts include barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, cadmium stearate, magnesium stearate. , Zinc stearate, zinc oleate, magnesium oleate, iron oleate, cobalt oleate, copper oleate, lead oleate, manganese oleate, zinc palmitate, cobalt palmitate, lead palmitate, magnesium palmitate, palmitate Aluminum oxide, calcium palmitate, lead caprylate, lead caprate, zinc linolenate, cobalt linolenate, calcium linolenate, zinc ricinoleate, cadmium ricinoleate and mixtures thereof There is a thing, but is not limited to this. Moreover, you may mix and use these. Among these, zinc stearate is most preferably used because it is particularly excellent in film formability on the intermediate transfer body 11.

  An inorganic lubricant refers to an inorganic compound that cleaves and lubricates itself or causes internal slip. Specific examples include talc, mica, boron nitride, molybdenum disulfide, tungsten disulfide, kaolin, smectite, hydrotalcite compound, calcium fluoride, graphite, plate-like alumina, sericite, and synthetic mica. However, it is not limited to this. Among these, boron nitride is most preferably used because hexagonal mesh surfaces in which atoms are firmly combined overlap with each other at a wide interval, and the force acting between the layers is only a weak van der Waals force. When boron nitride is used as an inorganic lubricant, toner slippage is satisfactorily suppressed or prevented by the dam effect that is dammed at the contact portion between the cleaning blade 76 and the transfer belt 11 and a nip is quickly formed.

  FIG. 3 shows data showing that the cleaning property is improved by the dam effect of boron nitride. In the figure, when a lubricant composed only of zinc stearate (ZnSt) is used, a lubricant obtained by mixing zinc stearate (ZnSt) and boron nitride (BN) at a ratio of 8: 2 is used. The same pattern (corresponding to the reference toner image) is input twice, and the result of a comparative experiment using a toner slipping ID to determine whether or not a cleaning failure has occurred is shown. From the figure, when a lubricant composed only of zinc stearate (ZnSt), which is a fatty acid metal salt, was used, cleaning failure occurred each time, but zinc stearate and boron nitride were mixed at 8: 2. In the case of using the lubricant, cleaning failure does not occur. This result shows that cleaning failure is prevented by the dam effect of boron nitride.

  However, inorganic lubricants typified by boron nitride have problems such as adhesion to an image carrier such as a photoreceptor, for example, filming of the photoreceptor, when applied in a large amount. Therefore, it is still mainstream to use zinc stearate as a lubricant, and it is mixed with a fatty acid metal salt in combination so that the coating ratio of the inorganic lubricant does not exceed the coating ratio of the fatty acid metal salt at most. It is normal. However, the smaller the application ratio of the inorganic lubricant, the smaller the effect of preventing the toner from slipping through the dam effect. Therefore, it is preferable that the inorganic lubricant can be applied as much as possible without limiting the application ratio.

  The lubricant application device 81 rotates the brush roller 83 to scrape the lubricant substance 82 and supplies the scraped lubricant substance 82 to the surface of the secondary transfer belt 65. Specifically, the brush roller 83 scrapes the solid lubricating material 82 by rubbing. As a result, the lubricating substance 82 in the form of fine powder adheres to the brush roller 83. Then, the adhering fine powdery lubricating material 82 is conveyed to a region facing the surface of the secondary transfer belt 65 as the brush roller 83 rotates, and is supplied to the surface of the secondary transfer belt 65.

  When the lubricant 82 supplied to the surface of the secondary transfer belt 65 reaches the secondary transfer portion 57 as the secondary transfer belt 65 rotates, the transfer is in contact with the secondary transfer belt 65 at this position. By being transferred to the belt 11, it is supplied from the secondary transfer belt 65 to the transfer belt 11. As described above, the lubricant application device 81 employs an indirect application method in which the lubricant 82 is supplied and applied to the transfer belt 11 via the secondary transfer belt 65.

  By attaching the lubricating substance 82 to the surface of the transfer belt 11, mechanical stress applied to the transfer belt 11 and the cleaning blade 76 during the above-described image forming process is greatly reduced, and transfer is also performed from discharge received by AC charging. The belt 11 is protected and the winding of the cleaning blade 76 is prevented or suppressed, and the life of the transfer belt 11 and the cleaning blade 76 is extended. Thereby, the cleaning performance is good over time, and filming is prevented or suppressed.

  The secondary transfer belt 65 is in contact with the transfer belt 11 at the secondary transfer portion 57 upstream of the cleaning blade 76 and downstream of the primary transfer portion 58 in the A1 direction. Therefore, residual toner on the transfer belt 11 and toner constituting the reference toner image may be transferred to the secondary transfer belt 65 in the secondary transfer portion 57.

  The cleaning device 64 removes the toner adhering to the secondary transfer belt 64 in this way and cleans the secondary transfer belt 65. The cleaning device 64 cleans the secondary transfer belt 65 in the rotation direction of the secondary transfer belt 65 on the upstream side of the application position of the lubricant 82 by the lubricant application device 81 and on the downstream side of the secondary transfer portion 57. Therefore, the secondary transfer belt 65 is in a clean state at the application position of the lubricating material 82 by the lubricant application device 81. Therefore, the toner or the like adhering to the secondary transfer belt 65 does not contaminate the lubricant application device 81, and the application performance of the lubricating material 82 by the lubricant application device 81 is maintained well, and the cleaning device 64 The cleaning performance of the secondary transfer belt 65 is also maintained, and thereby the good circulation of maintaining the coating performance of the lubricating substance 82 by the lubricant coating device 81 is continued.

  The lubricating substance 82 applied to the transfer belt 11 is stretched by the cleaning blade 76 when the cleaning blade 76 removes the residual toner and the reference toner image, and thereby the film of the lubricating substance 82 on the transfer belt 11. The effect | action which forms is produced.

Here, the reason why the above-described indirect coating method is employed in the image forming apparatus 100 will be described.
In general, immediately after applying the lubricant, it adheres to the object in the form of powder or particles and is not yet in the form of a film, so it is easily peeled off from the object and easily transferred to another contact object. Therefore, when the lubricant material 82 is applied to the transfer belt 11 at an adjacent position on the upstream side or the downstream side of the cleaning blade 76 in the A1 direction by arranging the lubricant application device 81 in the cleaning device 13 or the like, There are the following problems.

  That is, as shown in FIG. 7A, when the lubricating material 82 is applied to the transfer belt 11 at an adjacent position downstream of the cleaning blade 76 in the A1 direction, it reaches the primary transfer portion 58 immediately after the application. Therefore, the lubricating substance 82 is easily transferred to the photosensitive drums 20Y, 20M, 20C, and 20BK in the form of powder and particles, and the filming of the photosensitive drums 20Y, 20M, 20C, and 20BK, the photosensitive drum 20Y, The possibility of sticking to 20M, 20C, 20BK is increased.

  On the other hand, when the lubricating substance 82 is applied to the transfer belt 11 at an adjacent position on the upstream side of the cleaning blade 76 in the A1 direction, as shown in FIG. Since the film reaches the photosensitive drums 20Y, 20M, 20C, and 20BK after being formed on the transfer belt 11, the risk of transfer to the photosensitive drums 20Y, 20M, 20C, and 20BK is reduced, but the transfer belt 11 is reduced. A large amount of the residual toner and the toner constituting the reference toner image can be input to the brush roller 83. Since the input toner becomes an abrasive and scrapes the lubricating material 82, the supply amount and the coating amount of the lubricating material 82 become unstable due to fluctuations in the toner input amount.

  Therefore, the image forming apparatus 100 employs the indirect coating method described above, supplies the necessary amount of the lubricant 82 to the transfer belt 11 without being restricted by the filming of the photosensitive drums 20Y, 20M, 20C, and 20BK, and performs cleaning. The improvement of the nature is aimed at. In the indirect application method, as shown in FIG. 4A, when the image forming apparatus 100 is configured such that the photosensitive drums 20Y, 20M, 20C, and 20BK are located above the transfer belt 11, FIG. Compared with the direct application method in which the lubricant application device 81 is disposed on the transfer belt 11, the space for the lubricant application device 81 is omitted above the transfer belt 11, so that the size of the device can be reduced. There is also an advantage.

  However, in the image forming apparatus 100 employing the indirect application method, the lubricating material 82 applied to the secondary transfer belt 65 when the transfer sheet S passes through the secondary transfer unit 58 during normal image formation. Since most of the material adheres to the back surface of the transfer paper S and is consumed, the lubricant 82 is supplied to the transfer belt 11 because the secondary transfer belt 65 is transferred to the transfer belt 11 at the break of the transfer paper S. The application efficiency of the lubricating substance 82 is not necessarily high. Therefore, when the indirect application method is simply employed, the lubricating material 82 necessary for cleaning the reference toner image, which is an untransferred toner carried on the transfer belt 11, is supplied to the transfer belt 11 for process control. May be insufficient. In such a case, when the reference toner image is formed during the process control, the amount of the lubricating material 82 on the transfer belt 11 is less than the amount necessary for cleaning the reference toner image, which hinders the cleaning of the transfer belt 11. There is a risk of coming.

  Therefore, in the image forming apparatus 100, in addition to the indirect application method, when the reference toner image is formed, the amount of the lubricating material 82 supplied to the transfer belt 11 is increased by the control by the control unit 91. Therefore, the amount of the lubricating material 82 on the transfer belt 11 is ensured, and the prevention of filming of the photosensitive drums 20Y, 20M, 20C, and 20BK and the ensuring of the cleaning property of the transfer belt 11 are achieved. Therefore, the control unit 91 controls the passage mode of the transfer sheet S in the secondary transfer unit 57 so that the amount of the lubricating material 82 on the transfer belt 11 in the portion carrying the reference toner image increases. In this regard, the control unit 91 functions as a recording medium passage mode control unit.

  Specifically, the control unit 91 functioning as the recording medium passage mode control unit sets the passage mode of the transfer sheet S in the secondary transfer unit 57 until the reference toner image is carried on the transfer belt 11. By making the transfer belt 11 idle, that is, without providing a special mechanism, the time and area where the secondary transfer belt 65 contacts the transfer belt 11 can be increased by changing the control sequence without providing a special mechanism. By increasing the supply amount of the lubricating material 82 on the next transfer belt 65 to the transfer belt 11, the amount of the lubricating material 82 on the transfer belt 11 in the portion carrying the reference toner image is increased.

  The transfer belt 11 may be idled after the start of process control or before the start of process control after the end of normal image formation. As described above, when the process control is executed, the secondary transfer belt 65 is kept in contact with the transfer belt 11 in the secondary transfer portion 57, so that the transfer belt 11 is idled after the process control is started. Thus, the supply amount of the lubricating substance 82 on the secondary transfer belt 65 to the transfer belt 11 is increased without providing a special mechanism.

  As described above, when the transfer belt 11 is idled, the control unit 91 functioning as a transfer member drive control unit increases the rotation speed of the secondary transfer belt 65. In this respect, the control unit 91 functions as a transfer member rotation speed control unit. As a result, the area where the secondary transfer belt 65 contacts the transfer belt 11 is further increased by changing the control sequence without providing a special mechanism, and the lubricant 82 on the secondary transfer belt 65 is transferred to the transfer belt 11. The supply amount of further increases. Even during normal image formation, the rotational speed of the secondary transfer belt 65, that is, the moving speed, that is, the rotational speed of the transfer belt 11, that is, the transfer speed of the transfer belt 11, that is, the transfer performance of the transfer sheet S in the secondary transfer unit 57 and the magnification error is limited. Since the linear velocity difference is provided between these moving speeds larger than the moving speed, the linear velocity difference becomes larger when the transfer belt 11 is idle, but the restriction is not imposed when the transfer belt 11 is idle. Regardless of the restrictions, the amount of the lubricating material 82 on the transfer belt 11 can be adjusted. However, such control is not essential, and when such control is not performed, the secondary transfer belt 65 or the transfer roller 70 shown in FIG.

  The time for which the transfer belt 11 is idled is set by the control unit 91 functioning as a recording medium passage mode control unit so that the amount of the lubricant 82 attached on the transfer belt 11 reaches the amount necessary for cleaning the reference toner image. Is done.

  Further, the control unit 91 functioning as a recording medium passage mode control unit increases the so-called inter-paper distance before the process control is started, so that the transfer mode of the transfer sheet S in the secondary transfer unit 57 is increased. By increasing the distance between the leading edge and the trailing edge of the transfer sheet S, the time and area for the secondary transfer belt 65 to contact the transfer belt 11 can be increased, and the lubricating material on the secondary transfer belt 65 can be obtained. By increasing the supply amount of 82 to the transfer belt 11, the amount of the lubricating material 82 on the transfer belt 11 at the portion carrying the reference toner image is increased. Thus, the amount can be increased by changing the control sequence without providing a special mechanism.

  As already described, since the control unit 91 counts the number of image formations as a condition for starting process control, the timing for increasing the inter-sheet distance is a predetermined number of times that the number of image formations starts process control. It is said that the number of times before.

  The number of times of image formation that starts process control and the amount of increase in the distance between sheets function as the recording medium passage mode control means. The controller 91 sets the adhesion amount of the lubricant 82 on the transfer belt 11 to an amount necessary for cleaning the reference toner image so that the decrease in the number of image formations per unit time is not excessive. .

  Further, as shown in FIG. 5, the control unit 91 functioning as the recording medium passage mode control unit sets the passage mode of the transfer sheet S in the secondary transfer unit 57 before the start of the process control. By changing the position of the transfer sheet S so that the width of the transfer sheet S in the width direction of the transfer belt 11 is decreased, the time and area where the secondary transfer belt 65 contacts the transfer belt 11 The amount of the lubricating material 82 on the transfer belt 11 in the portion carrying the reference toner image is increased by increasing the supply amount of the lubricating material 82 on the secondary transfer belt 65 to the transfer belt 11. In the drawing, a square area including the alphabets Y, M, C, and BK is a carrying area on the transfer belt 11 of the reference toner image of each color represented by each alphabet. As shown in the figure, the reference toner image of each color is formed in a difference area where the width of the transfer sheet S is reduced. In the difference area, after the sheet passing area is reduced, the lubricating material 82 of the secondary transfer belt 65 is supplied in the same state as when the transfer belt 11 is idle or the distance between the sheets is greatly increased. Therefore, it is possible to increase the amount of the lubricating material 82 on the transfer belt 11 at the portion carrying the reference toner image while performing normal image formation. Thus, the amount can be increased by changing the control sequence without providing a special mechanism. However, as a condition for performing this control, it is necessary that the transfer sheet S of the same size can be fed to the secondary transfer unit 57 in the vertical direction and the horizontal direction.

  As described above, since the control unit 91 counts the number of times of image formation as a condition for starting the process control, the timing for reducing the sheet passing area is a predetermined number of times for the number of times of image formation to start the process control. It is said that the number of times before. This suppresses a decrease in the number of image formations per unit time.

  Depending on the length of the transfer sheet S after the reduction of the sheet passing area, the timing for reducing the sheet passing area is set as the recording medium passing mode control means. The functioning control unit 91 is set so that the amount of adhesion of the lubricating substance 82 on the transfer belt 11 reaches the amount necessary for cleaning the reference toner image so that the decrease in the number of image formations per unit time is not excessive. Is done. In the case where the image formation is performed while the transfer sheet S is conveyed in the horizontal direction and the case where the image formation is performed while the transfer sheet S is conveyed in the vertical direction, the former requires a shorter time to complete the image formation. When forming an image on the transfer paper S, it is desirable to form the image while transporting it in the horizontal direction. Therefore, the timing for reducing the sheet passing area is set to be as late as possible. This control may be performed together with the control of the inter-paper distance, but the control is easy if the inter-paper distance is made constant.

  As is apparent from the above description, the reference toner image is formed in the maximum sheet passing area, that is, the area corresponding to the area where the transfer sheet S can pass, in the width direction of the transfer belt 11. In other words, the transfer belt 11 carries the reference toner image in the area where the transfer paper S can pass in the width direction. Therefore, as compared with the case where the reference toner image is formed in an area outside the maximum sheet passing area in the width direction of the transfer belt 11, the width of the transfer belt 11 and the photosensitive drums 20Y, 20M, 20C, and 20BK are included. The width of each element constituting the image forming units 60Y, 60M, 60C, and 60BK, the exposure width of the optical scanning device 8, and the like are small, and the image forming apparatus 100 is reduced in size and cost.

  Therefore, for example, as shown in FIG. 6, when the region where the transfer belt 11 carries the reference toner image is intermittent in the width direction, the lubricant 82 is disposed only in the region in the width direction. If the lubricant material 82 is supplied to the secondary transfer belt 65 corresponding to the region where the transfer belt 11 carries the reference toner image in the width direction of the transfer belt 11 in the width direction of the transfer belt 11, It is possible to ensure the cleaning performance of the reference toner image while minimizing the amount of the lubricating material 82 to be disposed.

  The control means 91 stores in the memory the passage mode of the transfer sheet S between the transfer belt 11 and the secondary transfer belt 65 described above in accordance with the lubricating material 82 on the transfer belt 11 at the site carrying the reference toner image. A lubricant amount control program is stored as a lubricant amount adjustment program for executing a lubricant amount adjustment method for adjusting the amount of the lubricant material 82 on the transfer belt 11 by controlling so that the amount of toner increases. is doing. In this respect, the control means 91 or the memory functions as a lubricant amount adjustment program storage means or a lubricant amount control program storage means. Such a lubricant amount adjustment program or lubricant amount control program is not limited to the memory provided in the control means 91, but also a semiconductor medium (for example, ROM, nonvolatile memory, etc.), an optical medium (for example, DVD, MO, MD, CD-R, etc.), magnetic media (for example, hard disk, magnetic tape, flexible disk, etc.) and other storage media, and such memory and other storage media can store such lubricant amount adjustment program or lubricant amount control. When the program is stored, a computer-readable recording medium storing the lubricant amount adjustment program or the lubricant amount control program is configured.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention described in the claims is not specifically limited by the above description. Various modifications and changes are possible within the scope of the above.

For example, the transfer member may be an endless belt like the secondary transfer belt 65 or a roller like the transfer roller 70.
In the embodiment described above, a two-component developer is used, but the developer may be a one-component developer. Further, the present invention is not a so-called tandem image forming apparatus such as the image forming apparatus 100 as long as the above-described indirect coating method can be adopted, and sequentially applies toner images of respective colors on a single photosensitive drum. The present invention can be similarly applied to a so-called one-drum type image forming apparatus that forms and superimposes each color toner image and obtains a color image, and also applies to a monochrome image forming apparatus instead of a color image forming apparatus. be able to.

  The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

DESCRIPTION OF SYMBOLS 11 Intermediate transfer body 65, 70 Transfer member 81 Lubricant supply means 82 Lubricant 90 Reference toner image detection means 91 Recording medium passage mode control means, transfer member rotation speed control means 100 Image forming apparatus A1 Movement direction of intermediate transfer body S Recording Medium

JP 2006-91179 A Japanese Patent Laid-Open No. 5-323704 JP 2007-272187 A JP 2008-134467 A JP 2008-96727 A JP 2003-330320 A JP 2002-244485 A JP 2008-304707 A JP 2008-233238 A Japanese Patent Laid-Open No. 11-174868 Japanese Patent Laid-Open No. 2007-140085 JP 2006-3859 A JP 2002-351258 A JP 2002-229341 A

Claims (9)

A transfer member for enabling transfer of a toner image on the intermediate transfer member to a recording medium passing between the intermediate transfer member, and
Lubricant supply means for supplying a lubricant to the intermediate transfer body via the transfer member by supplying a lubricant to the transfer member;
Recording medium passing mode control means for controlling the passing mode of the recording medium between the intermediate transfer member and the transfer member so as to increase the amount of lubricant on the intermediate transfer member at the portion carrying the reference toner image. Image forming apparatus. The image forming apparatus according to claim 1.
The recording medium passage mode control means sets the passage mode to a state where the intermediate transfer member is idle until the reference toner image is carried, so that the portion on the intermediate transfer member carrying the reference toner image is placed. An image forming apparatus characterized in that the amount of lubricant is increased. The image forming apparatus according to claim 2.
An image forming apparatus comprising transfer member rotation speed control means for increasing the rotation speed of the transfer member in the state. The image forming apparatus according to any one of claims 1 to 3,
The recording medium passage mode control means is configured to increase the interval of the recording medium passing between the intermediate transfer member and the transfer member so that the intermediate transfer at the portion carrying the reference toner image is performed. An image forming apparatus characterized in that the amount of lubricant on the body is increased. The image forming apparatus according to any one of claims 1 to 4,
The recording medium passage mode control means changes the position of the recording medium so that the width of the recording medium passing between the intermediate transfer member and the transfer member is reduced. An image forming apparatus characterized by increasing the amount of lubricant on an intermediate transfer member at a portion carrying a toner image. The image forming apparatus according to any one of claims 1 to 5,
The reference toner on the intermediate transfer member from the position where the intermediate transfer member carries the reference toner image in the moving direction of the intermediate transfer member to the position where the toner image on the intermediate transfer member is transferred to the recording medium by the transfer member. A reference toner image detecting means for detecting an image;
The image forming apparatus, wherein the transfer member is in contact with the intermediate transfer member in a state where the intermediate transfer member carries the reference toner image. The image forming apparatus according to any one of claims 1 to 6,
The intermediate transfer member carries a reference toner image in a region where the recording medium can pass in the width direction.
The image forming apparatus according to claim 1, wherein the lubricant applying unit supplies the lubricant to the transfer member in a width direction of the intermediate transfer member corresponding to a region where the intermediate transfer member carries a reference toner image. The image forming apparatus according to any one of claims 1 to 7,
The image forming apparatus, wherein the lubricant includes an inorganic lubricant, and the inorganic lubricant includes boron nitride. A transfer member for enabling transfer of a toner image on the intermediate transfer member to a recording medium passing between the intermediate transfer member, and
Lubricant supply means for supplying a lubricant to the intermediate transfer body via the transfer member by supplying a lubricant to the transfer member;
Using a recording medium passing mode control means for controlling the passing mode of the recording medium between the intermediate transfer member and the transfer member so that the amount of lubricant on the intermediate transfer member at the portion carrying the reference toner image is increased. A method for adjusting the amount of lubricant on the intermediate transfer member.

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