JP2014137382A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To identify, more accurately than prior art, a time point in a continuous image forming job at which an abnormal image with white streaks is generated, so as to stably suppress the generation of the abnormal image with white streaks without reducing productivity of image formation.SOLUTION: An image forming apparatus, upon reception of input of a continuous image forming job, determines a time point to interrupt the continuous image forming job from the average image area ratio in the continuous image forming job and the estimated wear amount of a cleaning blade, and performs idle rotation to rotate a photoreceptor while inhibiting a developing device from supplying toner to the photoreceptor during the interruption period of the continuous image forming job, so as to perform cleaning processing with the cleaning blade.

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and the like. Specifically, a toner image obtained by developing a latent image on a latent image carrier is finally transferred onto a recording material and the latent image is transferred. The present invention relates to an image forming apparatus that performs a cleaning process on a carrier.

  It is known that when a toner having a spherical shape and a small particle size is used, it is difficult to perform proper cleaning with a widely used blade cleaning method. This is due to the following reason. That is, in the blade cleaning method, the latent image carrier is driven to rotate, so that the cleaning blade removes the toner while rubbing the surface of the latent image carrier. Therefore, the contact edge portion of the cleaning blade is deformed by the frictional resistance with the latent image carrier, and a minute space is generated between the latent image carrier and the cleaning blade. The smaller the toner particle size, the easier it is to enter this space. Further, the closer the toner that has entered the shape to be spherical, the smaller the rolling frictional force, so that it easily rolls through the space between the latent image carrier and the cleaning blade. Therefore, when using a toner having a spherical shape and a reduced particle size, a large amount of toner passes through the cleaning blade. The toner that has passed through the cleaning blade remains on the surface of the latent image carrier without being removed from the latent image carrier, and the release agent or fluidizer contained in the toner causes the latent image. So-called filming that adheres to the surface of the carrier in the form of a film is generated. When such filming occurs, a white spot abnormality image is generated, such as a white spot in the solid portion of the image.

FIG. 8 is an explanatory diagram showing an example of a white spot abnormality image generated in a state where filming occurs due to the release agent or fluidizing agent in the toner adhering to the surface of the latent image carrier.
This white spot abnormality image is a solid part of a medaka shape in the solid portion of the image, and appears on the image at a cycle corresponding to the circumference of the latent image carrier. The white spot abnormal image is particularly noticeable when a uniform halftone image is printed on the entire surface of the paper.

  Conventionally, a lubricant composed of a fatty acid metal salt or the like is applied to the surface of the latent image carrier in order to improve the cleaning property of the latent image carrier and suppress the occurrence of filming when using a toner having a spherical or small particle size. An image forming apparatus for coating is known (Patent Document 1). In this image forming apparatus, by forming a thin film of a lubricant on the surface of the latent image carrier, the friction coefficient between the toner and the surface of the latent image carrier can be reduced, and the cleaning performance by the cleaning blade is improved. improves.

  Further, Patent Document 2 discloses an image forming apparatus that can suppress the occurrence of an abnormal white spot image even when an image is formed under conditions that are likely to cause an abnormal white spot image. In Patent Document 2, the following two conditions are shown as conditions for easily generating a white spot abnormality image.

  The first is a case where images having a high image area ratio are continuously formed. Since a large amount of untransferred toner is generated when an image with a high image area ratio is formed, a large amount of toner passes through the cleaning blade. As a result, if a large amount of toner is input to the lubricant application brush and such a state continues, the toner may solidify with the lubricant application brush. In addition, in the case of applying a powdered lubricant scraped from a solid lubricant by a lubricant application brush, a large amount of toner input to the lubricant application brush is also input to the solid lubricant. The toner may solidify. Once in such a state, the lubricant cannot be applied uniformly and stably, and a portion with a high friction coefficient is locally generated on the surface of the latent image carrier, and filming occurs in such a portion. Deposits that are the core of generation are likely to adhere. As a result, filming occurs and an abnormal image as shown in FIG. 8 is generated.

  Also. The second case is a case where images having a low image area ratio are continuously formed. At the time of image formation with a low image area ratio, the amount of toner remaining after transfer is small, so that there is little toner that passes through the cleaning blade, and there is little toner that is input to the lubricant application brush. When the amount of toner input to the lubricant application brush is small, the amount of lubricant scraped by the lubricant application brush may be reduced in a configuration in which the powdered lubricant scraped from the solid lubricant is applied by the lubricant application brush. Are known. In general, since the amount of lubricant supplied from the lubricant application brush is uneven, if the amount of lubricant scraped by the lubricant application brush decreases and the supply amount of lubricant from the lubricant application brush decreases, A portion where the lubricant is insufficient is formed on the surface of the latent image carrier, and the friction coefficient of the portion is increased. Therefore, when images with a low image area ratio are continuously formed, portions having a high friction coefficient are created on the surface of the latent image carrier, and deposits that are the core of filming adhere to such portions. It becomes easy to do. As a result, filming occurs and an abnormal image as shown in FIG. 8 is generated.

  According to the above-mentioned Patent Document 2, the time when an abnormal white-out image is generated in a continuous image forming job having such a high image area ratio or a low image area ratio is formed in the continuous image forming job by a prior experiment or the like. It can be specified with high accuracy from the image area ratio of a toner image and a predetermined number of image formations in which a predetermined abnormal image is generated when continuous image formation is performed at the image area ratio. In the image forming apparatus disclosed in Patent Document 2, based on this knowledge, when an input of a continuous image forming job is received, an image area ratio of a toner image formed on the latent image carrier in the continuous image forming job, The timing for interrupting the continuous image forming job is determined based on a predetermined number of image formations (number of sheets to be passed) in which a white spot abnormal image is generated when continuous image formation is performed at the image area ratio. Then, during the interruption period, the cleaning process is performed by performing idling rotation that rotates the latent image carrier in a state where the toner supply to the latent image carrier by the developing unit is prohibited.

  Here, the idle rotation of the latent image carrier means that the latent image carrier is rotated in a state where the toner supply to the latent image carrier by the developing unit is prohibited. Accordingly, during the idling of the latent image carrier, there is almost no toner on the latent image carrier. Under such circumstances, the rubbing force of the cleaning member against the latent image carrier is It is better than the situation where toner is supplied. As a result, the filming-causing substance on the latent image carrier that could not be removed during image formation can be removed by rubbing the cleaning member. Therefore, according to the image forming apparatus disclosed in Patent Document 1, the film on the latent image carrier grown by the continuous image formation in the continuous image forming job by the cleaning process performed during the interruption period. It is possible to remove the cause of filming and reset the surface state related to filming on the latent image carrier.

  However, as a result of the inventor's research, it has been found that in the image forming apparatus disclosed in Patent Document 2 described above, the accuracy of specifying the timing of occurrence of a white spot abnormal image in the continuous image forming job is not yet sufficient. Therefore, if priority is given to suppressing the occurrence of white spot abnormal images and the interrupt timing is determined earlier with a sufficient margin than the specified white spot abnormal image occurrence timing, There is a problem that the frequency increases and the productivity of image formation decreases. On the other hand, when priority is given to suppressing the decrease in image formation productivity and the interruption time is determined immediately before the specified white defect abnormal image occurrence time, a white defect abnormal image occurs before the interruption. There is a problem that there is a risk of it.

  As a result of earnest research, the present inventor has found that the timing of occurrence of an abnormal white image during a continuous image forming job varies significantly depending on the cleaning performance (adhesion removal performance by the cleaning member) during the continuous image forming job. I found it. As described above, the white spot abnormality image generated during a continuous image forming job with a high image area ratio is caused by filming, and the occurrence of filming depends on the amount of toner that has passed through the cleaning blade. In general, the amount of toner that passes through the cleaning blade varies depending on the cleaning performance (attachment removal performance) of the cleaning blade. Therefore, for example, a new cleaning blade with high cleaning performance and a cleaning blade that has deteriorated due to wear over time are different in cleaning performance, and the amount of toner that passes through the cleaning blade differs. As a result, due to the difference in cleaning performance, the timing of occurrence of an abnormal white spot image during a continuous image forming job changes.

  The above problems are not limited to the blade cleaning method using a cleaning blade as a cleaning member, but also occur in a cleaning method in which a latent image carrier is cleaned by rubbing using another cleaning member such as a cleaning brush. It is a problem to get.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and the object of the present invention is to specify the time when a white spot abnormal image occurs in a continuous image forming job with higher accuracy and reduce the productivity of image formation. It is an object of the present invention to provide an image forming apparatus that can stably suppress the occurrence of white spot abnormal images.

  In order to achieve the above object, the present invention develops a latent image on a latent image carrier to be rotationally driven with toner by a developing means upon receipt of an image forming job, and a toner image obtained thereby Is finally transferred onto the recording material, and when a continuous image forming job for continuously forming images on a plurality of recording materials is received, the continuous image forming job is Cleaning during which the latent image carrier is rubbed with a cleaning member while rotating the latent image carrier while the toner is not supplied to the latent image carrier by the developing means during the interruption period. In the image forming apparatus that performs the processing, the deposit removing performance value calculating unit that calculates the deposit removing performance value by estimating the deposit removing performance by the cleaning member, and the continuous image forming job If the force is received, based on the image area ratio of the toner image formed on the latent image carrier in the continuous image forming job and the deposit removal performance value calculated by the deposit removal performance value calculation means, Job interruption control means for determining the interruption timing of the continuous image forming job and performing the cleaning process during the interruption period of the continuous image forming job is provided.

  In the present invention, similar to the image forming apparatus disclosed in Patent Document 2, the job is interrupted during a continuous image forming job, and the latent image carrier is idled during the interruption period to perform cleaning by rubbing the cleaning member. Processing (hereinafter referred to as “refresh processing”) is performed. Thus, the filming-causing substance on the latent image carrier that has grown by the continuous image formation during the continuous image forming job is removed, and the surface state related to filming on the latent image carrier is reset. In the present invention, the interruption time at this time is determined from the image area ratio of the toner image formed on the latent image carrier in the continuous image forming job and the deposit removal performance value indicating the deposit removal performance by the cleaning member. ,It is determined. As described above, the timing of occurrence of a white spot abnormality image during a continuous image forming job varies depending on the difference in the deposit removal performance (cleaning performance). Therefore, in the present invention, even when the deposit removal performance (cleaning performance) changes, it is possible to specify with high accuracy the time when a white spot abnormal image occurs during a continuous image forming job, and the appropriate interruption time. Can be determined with high accuracy.

  As described above, according to the present invention, it is possible to specify the time when the white spot abnormal image occurs in the continuous image forming job with higher accuracy, and to perform the refresh process at an appropriate interruption time. An object of the present invention is to provide an image forming apparatus capable of stably suppressing the occurrence of a white spot abnormality image without dropping.

FIG. 2 is an explanatory diagram illustrating a schematic configuration of a main part of the printer according to the embodiment. FIG. 2 is an explanatory diagram illustrating a schematic configuration of an image forming unit of the printer. 6 is a graph showing a relationship between an image area ratio and the number of continuous sheets that pass until an abnormal white image is generated in the printer. It is a graph which shows the relationship between the surface friction coefficient of a photoreceptor, and the number of generation | occurrence | production of a white spot abnormal image. 6 is a graph showing the relationship between the cumulative travel distance of the photoconductor in the printer and the idling time of the photoconductor required for removing an abnormal white spot image. It is explanatory drawing for demonstrating the division | segmentation of a low-temperature low-humidity (LL) environment, middle temperature middle humidity (MM) environment, and high temperature high humidity (HH) environment. It is an example of the image in which the white spot abnormality image has generate | occur | produced in LL environment. It is an example of the image in which the white spot abnormality image has generate | occur | produced in the HH environment.

Hereinafter, an embodiment in which the present invention is applied to a printer which is an electrophotographic image forming apparatus will be described.
FIG. 1 is an explanatory diagram showing a schematic configuration of a main part of the printer according to the present embodiment.
As shown in FIG. 1, the printer includes image forming units 102Y (yellow) and 102M (magenta) along an intermediate transfer belt 101 as an intermediate transfer member that is a transfer material stretched by a plurality of stretching rollers. , 102C (cyan), 102K (black). The toner images formed by the image forming units 102Y, 102M, 102C, and 102K are transferred onto the intermediate transfer belt 101 by primary transfer devices 106Y, 106M, 106C, and 106K as transfer means. The intermediate transfer belt 101 is pressed toward the photoconductor 202 via the primary transfer device 106. Further, an image detection device 110 as a toner adhesion amount detection unit for detecting the toner adhesion amount of the toner image transferred onto the intermediate transfer belt is provided to face the intermediate transfer belt 101.

  The toner image on the intermediate transfer belt 101 is transferred by the secondary transfer device 111 to the transfer paper 112 as a recording material fed from the paper feeding device 115. Thereafter, the transfer paper 112 on which the toner image has been transferred undergoes a fixing process by the fixing device 116 and is discharged out of the apparatus.

FIG. 2 is an explanatory diagram showing a schematic configuration of the image forming units 102Y, 102M, 102C, and 102K. Since the image forming units 102Y, 102M, 102C, and 102K have the same configuration, the following description will be made without distinguishing each other.
Around the photoconductor 202 is a charging device 201 as a charging unit that charges the surface of the photoconductor to a negative polarity, and an exposure unit that writes an electrostatic latent image by reducing the potential of the photoconductor surface by exposure with the writing light L. Writing device 203, developing device 205 as a developing unit that develops an electrostatic latent image with negative polarity charged toner, photoconductor cleaner 300 as a cleaning unit that cleans transfer residual toner and the like on the photoconductor, friction on the surface of the photoconductor Lubricant application device 400 as a lubricant supply means for supplying a lubricant to lower the coefficient, erase (static elimination device) 207 as a static elimination means for removing static electricity by irradiating the surface of the photoreceptor with static elimination light, and potential measurement means The potential sensor 210 is provided.

  The charging device 201 according to the present embodiment is a non-contact type charger composed of a scorotron charger, and the grit voltage (charging bias) Vg of the scorotron charger is set to a target charging potential (in this embodiment, a negative potential). The surface potential of the photosensitive member 202 is set to the target charging potential. Further, the charging device 201 is not limited to this, and other non-contact chargers or contact chargers can also be used.

  The writing device 203 of the present embodiment uses a laser diode (LD) as a light source, and irradiates intermittent writing light, that is, repetitive pulsed writing light L, so that electrostatic charge for each dot is formed on the surface of the photoreceptor. A latent image (hereinafter referred to as “1-dot electrostatic latent image”) is formed. In this embodiment, gradation control is performed by changing the exposure time (unit exposure time) when forming a 1-dot electrostatic latent image to control the amount of toner attached to the 1-dot electrostatic latent image. It is possible. In the present embodiment, the maximum unit exposure time is divided into 15 (each unit exposure time is hereinafter referred to as “exposure duty”), and gradation control of 16 gradations is possible. Therefore, in the present embodiment, the exposure duty can be adjusted in 16 steps from 0 (not exposed) to 15 (maximum unit exposure time).

  The developing device 205 according to the present embodiment includes a developing roller as a developer carrying member disposed opposite to the surface of the photosensitive member 202, and includes a toner charged with a predetermined polarity (in this embodiment, a negative polarity) and a magnetic carrier. The two-component developer thus formed is carried on the developing roller, and toner is supplied to the surface of the photoreceptor 202. A developing bias Vb whose absolute value is sufficiently larger than the exposed portion potential VL and sufficiently smaller than the charging potential Vd is applied to the developing roller. As a result, in the developing area where the surface of the photoconductor 202 and the developing roller face each other, the toner is moved toward the electrostatic latent image (exposed portion) on the surface of the photoconductor, and the non-electrostatic latent image on the surface of the photoconductor 202 is obtained. An electric field that does not move the toner can be formed on the image (non-exposed portion), and the electrostatic latent image can be developed with the toner.

  When image formation is performed, first, the surface of the photoconductor 202 is charged by the charging device 201 so that the surface of the photoconductor 202 is uniformly at a target charging potential (negative potential). Next, the surface portion of the charged photoconductor 202 is exposed to the photoconductor 202 from the light source (LD) of the writing device 203 with the writing light L corresponding to the image data, whereby the exposed portion on the surface of the photoconductor 202 is exposed. As a result, the electrostatic latent image is formed on the surface of the photoconductor 202. Thereafter, the electrostatic latent image (exposed portion in this embodiment) formed on the surface of the photosensitive member 202 is developed into a toner image by toner carried on a developing roller which is a developer carrying member of the developing device 205. Is done. Specifically, a developing bias Vb having an absolute value larger than the exposure portion potential VL and smaller than the charging potential Vd is applied to the developing roller, and the toner charged to a predetermined polarity (negative polarity in this embodiment) is applied. Development is performed by electrostatically attaching to the electrostatic latent image.

  The toner image formed on the photoreceptor 202 is transferred onto the intermediate transfer belt 101 by the primary transfer device 106. Untransferred toner remaining on the photoconductor 202 without being transferred to the intermediate transfer belt 101 is collected by the photoconductor cleaner 300. Lubricant is applied to the surface portion of the photoconductor cleaned by the photoconductor cleaner 300 by the lubricant application device 400, and the static electricity is uniformly irradiated by the eraser 207 to remove the non-electrostatic latent image portion. Is uniformly discharged.

  The toner images of the respective colors formed by the image forming units 102Y, 102M, 102C, and 102K in this way are primarily transferred onto the intermediate transfer belt 101 so as to overlap each other. Thereafter, each color toner image transferred onto the intermediate transfer belt 101 is transferred from the intermediate transfer belt 101 to the transfer paper 112 by the secondary transfer device 111. At this time, the transfer residual toner that is not transferred onto the transfer paper 112 but remains on the intermediate transfer belt 101 is collected by the intermediate transfer belt cleaner 114.

FIG. 3 is a schematic diagram showing the configuration of the photoreceptor cleaner 300 and the lubricant application device 400.
The photoconductor cleaner 300 according to the present exemplary embodiment includes a cleaning fur brush 332 that is a cleaning member that contacts the photoconductor 202 and a transfer roller 334 that transfers transfer residual toner removed from the photoconductor 202 in the case 331. A cleaning blade 335 as a cleaning member is incorporated. Further, the case 331 is provided with an inlet seal 333 to prevent the transfer residual toner collected by the fur brush 332 and the cleaning blade 335 from scattering.

  Further, the lubricant application device 400 according to the present embodiment includes a brush roll 415 that is a rotating member as a lubricant supply member that contacts both the solid lubricant 420 and the photoreceptor 202. A solid lubricant 420 is pressed against the brush roll 415 by pressing means, and a powdery lubricant scraped off from the solid lubricant 420 by the brush roll 415 is applied to the photoreceptor 202. The pressing means is disposed between the unit main body member 411 and the solid lubricant 420, and between the compression spring 412 that presses the solid lubricant 420 toward the brush roll 415, and between the compression spring 412 and the solid lubricant 420. And a holder 414 which is a holding portion for the solid lubricant 420.

  Further, the lubricant application device 400 includes a leveling member 416 formed of a thermoplastic or thermosetting urethane blade that uniformly levels the lubricant applied to the photoreceptor 202 by the brush roll 415. By providing the leveling member 416, the lubrication effect can be improved. The leveling member 416 may not be used as long as the lubricant applied by the brush roll 415 and the lubrication state can sufficiently withstand the required specifications without the leveling member.

  As the solid lubricant 420 in the present embodiment, for example, zinc stearate can be used. As this zinc stearate, a solid lubricant prepared by melting and solidifying zinc stearate manufactured by Nippon Oil & Fats Co., Ltd., SZ2000 manufactured by Sakai Chemical Co., Ltd., or the like can be used. The lubricant is not limited to zinc stearate, and other materials having a lubricating effect such as potassium stearate, aluminum stearate, calcium stearate and the like may be used.

  Further, the brush roll 415 of this embodiment is rotationally driven by a drive motor 512, and the rotational speed of the drive motor 512 is controlled by a rotation control device 520 independently of the rotation of the photoconductor 202.

  The brush roll 415 is formed into a roll shape by winding a brush in which 50000 filaments of PET fiber having a thickness of 6 denier and having a low resistance (order of 10 2) are implanted on a metal core. Something is used. The brush material of the brush roll 415 is not limited to PET fiber, and acrylic fiber, polyamide synthetic fiber, or the like may be used, or non-conductive fiber may be used. In addition to the brush roll, other members such as foamed urethane may be used as long as they have a solid lubricant scraping ability. Note that the lubricant scraping member and the lubricant application member may be configured separately.

Next, filming that suppresses the occurrence of filming, which is a feature of the present invention, so as not to generate an abnormal white spot image in which a solid white portion of the image is formed in the solid portion of the image by filming during a continuous image forming job. The suppression control will be described.
In the present embodiment, the timing at which a white spot abnormal image occurs in the continuous image forming job is specified in advance, the continuous image forming job is interrupted before the time comes, and the photosensitive member 202 is interrupted during the interruption period. Is rotated idly to perform a refresh process to be described later. More specifically, in this embodiment, each time 1000 sheets are passed, it is determined whether to interrupt the continuous image forming job and execute the refresh process.

Here, an example of a method for determining the interruption time for executing the refresh process, that is, an example of a method for determining whether or not to execute the refresh process when determining every 1000 sheets will be described.
As described in Patent Document 2, generally, the higher the image area ratio, the smaller the number of continuous sheets that pass until a white spot abnormality image occurs. That is, the higher the image area ratio, the earlier the white spot abnormal image occurs. Further, as described above, the timing of occurrence of an abnormal white image during a continuous image forming job varies depending on the cleaning performance during the continuous image forming job. Therefore, in the present embodiment, the deposit removal performance indicating the average value of the image area ratio (average image area ratio) after starting the continuous image forming job and the deposit removal performance (cleaning performance) by the cleaning blade 335. Whether or not to perform the refresh process is determined from the estimated cleaning blade wear amount.

FIG. 4 is a graph showing the relationship between the average image area ratio after the start of the continuous image forming job, the estimated wear amount of the cleaning blade, and the occurrence of filming (occurrence of a white spot abnormal image).
This graph shows an orthogonal coordinate system with the horizontal axis representing the average image area ratio after the start of the continuous image forming job and the vertical axis representing the estimated wear amount of the cleaning blade. It is divided into three areas A, B, and C according to the difference in the occurrence status). This classification is based on the experiment results of the present inventors.

  In this graph, a region A indicates a region where filming does not occur (a region where no white defect abnormal image occurs). A region B indicates a region where filming does not occur (a region where an abnormal white-out image does not occur) when the lubricant application amount is increased as compared with the normal image forming operation. A region C is a region where filming occurs only by increasing the lubricant application amount (a region where an abnormal white defect image occurs).

FIG. 5 is a flowchart showing a flow of filming suppression control in the present embodiment.
When an image forming job is input (S1), the main body control unit 500 performs an image forming operation according to the contents of the image forming job (S2). The main body control unit 500 increments the continuous sheet passing count value by one for each image forming operation (an operation for forming an image on one transfer sheet 112) (S5). The initial value of the continuous sheet passing count value is zero. The image forming operation is continuously performed according to the contents of the image forming job. When the image forming job is completed (Yes in S3), the continuous sheet count value is reset to the initial value (S4), and the control is ended.

  On the other hand, when a continuous image forming operation is performed and the continuous sheet passing count value reaches 1000 (Yes in S6), the main body control unit 500 calculates an average image area ratio at the time of image formation of the last 1000 sheets (S7). ). In addition, the main body control unit 500 calculates an estimated wear amount of the cleaning blade that has been worn by the last 1000 image formation (S8).

FIG. 6 is a graph showing the results of measuring the amount of cleaning blade wear when 1000 images were printed at a constant image area ratio.
In this graph, the horizontal axis represents the image area ratio and the vertical axis represents the amount of cleaning blade wear. This graph shows three cases in which the lubricant application amount by the lubricant application device 400 is different. The amount of wear of the cleaning blade varies depending on the image area ratio of the formed image and the amount of lubricant applied because the cleaning blade is worn by the passage of the toner and lubricant when the toner and lubricant pass through the cleaning blade. It is. The amount of toner and lubricant passing through the cleaning blade increases as the amount of toner and lubricant input to the cleaning blade increases. As the image area ratio of the formed image is higher, the amount of residual toner is increased and the amount of toner passing through the cleaning blade is increased, so that the amount of wear of the cleaning blade is increased. Further, as the lubricant application amount increases, the amount of lubricant passing through the cleaning blade increases, so that the amount of wear of the cleaning blade increases.

  As described above, the wear amount of the cleaning blade that is worn during the formation of 1000 images has a correlation between the image area ratio (average image area ratio) of the formed image and the lubricant application amount. Since this correlation can be grasped in advance by an experiment or the like, the wear amount of the cleaning blade that wears during an image forming job for forming 1000 images depends on the average image area ratio of the image forming job and the lubricant. It is possible to estimate with sufficient accuracy from the coating amount. When the amount of lubricant applied is considered to be substantially constant, the wear amount of the cleaning blade that wears during an image forming job for forming 1000 images is estimated from the average image area ratio of the image forming job. Is possible.

  When calculating the estimated wear amount of the cleaning blade during the image formation for the immediately preceding 1000 sheets (S8), the main body control unit 500 calculates the average image area ratio in the image formation for the immediately preceding 1000 sheets calculated in the processing step S7 and the previous 1000 sheets. The amount of lubricant applied during the image formation is acquired. The lubricant application amount can be estimated from, for example, the rotational speed information of the brush roll 415 during the image formation immediately before 1000 sheets. Then, the main body control unit 500 refers to the correlation information indicating the correlation as shown in FIG. 6 from the acquired average image area ratio and lubricant application amount, and estimated cleaning blade wear that has been worn by the last 1000 image formations. Calculate the amount.

  Thereafter, the main body controller 500 determines that the average image area ratio and the estimated wear amount of the cleaning blade at the time of image formation for the immediately preceding 1000 sheets calculated in this way are the three areas A and B in the orthogonal coordinate system shown in FIG. To which area C belongs. In this determination, if it is determined that it belongs to the region B (Yes in S9), as described above, filming does not occur if the lubricant application amount is increased as compared with the normal image forming operation. 500 increases the lubricant application amount to a set amount larger than the standard amount (S10). Thereafter, after resetting the continuous sheet passing count value to zero (S14), the process returns to the remaining image forming operation of the image forming job.

  As a method of increasing or decreasing the amount of applied lubricant, (1) a method of changing the pressing force of the solid lubricant 420 to the brush roll 415, (2) a method of changing the rotational speed of the brush roll 415, (3) a brush roll Examples include a method of changing the fiber type, fiber diameter, and flocking density of 415, and (4) a method of changing the hardness (easy to cut) of the solid lubricant 420. Among these methods, the methods (1), (3), and (4) are very difficult to change during the image forming job to increase or decrease the coating amount of the solid lubricant 420. Therefore, in the present embodiment, a method is adopted in which the rotational speed of the brush roll 415 can be controlled independently of the photoconductor 202, and the rotational speed of the brush roll 415 is changed to increase or decrease the coating amount of the solid lubricant 420. Adopted.

  Further, when the main body control unit 500 determines that it belongs to the region C (Yes in S11), as described above, filming occurs when the lubricant application amount increases, so the continuous image forming job is interrupted, During the interruption period, a refresh process for performing the idling operation of the photoconductor 202 is executed (S12). Thereafter, if necessary, the lubricant application amount is set to a standard amount (S13), the continuous sheet passing count value is reset to zero (S14), and the process returns to the remaining image forming operation of the image forming job.

  In this refresh process, during the idling operation of the photoconductor 202, the operations of the photoconductor cleaner 300 and the lubricant applying device 400 are normal, but the operations of the charging device 201, the writing device 203, and the developing device 205 are stopped. Let By doing so, the toner density and the toner charge amount of the developer do not change during the idling operation, and it is possible to prevent the deterioration of the photoreceptor due to the charging process. By such a refresh process, the filming-causing substance on the photoconductor 202 is removed, so that the filming that has been formed can be prevented from occurring and the filming state on the photoconductor can be reset.

  Here, the time during which the photoconductor 202 is idly rotated during the refresh process during the interruption period of the continuous image forming job may be a predetermined time. However, the cumulative travel distance of the photoconductor 202 (from the initial time point) may be used. The idling time may be changed according to the cumulative travel distance. Specifically, since the filming cause substance tends to be more difficult to remove as the cumulative travel distance of the photoconductor 202 becomes longer, the idling time is controlled to be longer as the cumulative travel distance of the photoconductor 202 becomes longer. .

  When the main body control unit 500 determines that it belongs to the region A (No in S11), filming does not occur as described above, so the lubricant application amount is set to a standard amount as necessary (S13). ) After resetting the continuous sheet passing count value to zero (S14), the process returns to the remaining image forming operation of the image forming job.

  When continuously forming images with a low image area ratio with an image area ratio of 5% or less, the surface friction coefficient of the photosensitive member 202 increases due to insufficient toner input. Is likely to occur. However, in this embodiment, although a detailed description is omitted, a toner pattern is formed between images during continuous image formation for process control. Therefore, a toner input corresponding to an image area ratio of at least 5% is always input. As a result, no white defect abnormal image occurs.

  In addition, the occurrence of a white spot abnormality image may be affected by the environment of the printer (temperature, humidity, etc.) in which the printer is installed. It may be determined whether the job is interrupted and the refresh process is executed.

[Modification]
Next, a modified example of the photoreceptor cleaner 300 and the lubricant application device 400 in the above embodiment will be described.
FIG. 7 is a schematic diagram showing a lubricant application device in the present modification example in which the constituent members of the photoreceptor cleaner 300 and the lubricant application device 400 in the above-described embodiment are shared (shared).
The lubricant application device 600 of this modification is one in which the number of parts is reduced by using the constituent member also as a photoreceptor cleaner. Specifically, the blade member 616 in this modification serves as both the cleaning blade 335 in the photoreceptor cleaner 300 and the leveling member 416 in the lubricant applying device 400. However, in this modification, the variation in the amount of lubricant applied is more likely to be affected by the amount of residual transfer toner than in the above-described embodiment. Don't be.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
[Aspect A]
By receiving the input of the image forming job, the latent image on the latent image carrier such as the photosensitive member 202 that is driven to rotate is developed with toner by the developing unit such as the developing device 205, and the resulting toner image is finally obtained. In addition, the toner image is transferred onto a recording material such as the transfer paper 112, and the latent image carrier to be rotated is rubbed with a cleaning member such as the cleaning blade 335 and the blade member 616, thereby unnecessary attachment on the latent image carrier. In the image forming apparatus that performs the cleaning process for removing the kimono, the deposit removing performance of the main body control unit 500 or the like that calculates the deposit removing performance value such as the estimated amount of wear of the cleaning blade by estimating the deposit removing performance by the cleaning member Upon receipt of the value calculation means and a continuous image forming job for continuously forming images on a plurality of recording materials, The continuous image formation based on the image area ratio (average image area ratio, etc.) of the toner image formed on the latent image carrier with the deposit and the deposit removal performance value calculated by the deposit removal performance value calculation means. The timing for suspending the job is determined, and during the interruption period of the continuous image forming job, idle rotation is performed to rotate the latent image carrier in a state where the toner supply to the latent image carrier by the developing unit is prohibited. And a job interruption control unit such as a main body control unit 500 for performing the cleaning process.
According to this, even when the deposit removal performance (cleaning performance) changes, it is possible to identify with high accuracy the timing of occurrence of an abnormal white spot image in a continuous image forming job, and to set an appropriate interruption timing with high accuracy. It becomes possible to decide. As a result, since the refresh process can be performed at an appropriate interruption time, it is possible to stably suppress the occurrence of a white spot abnormality image without reducing the image formation productivity.

[Aspect B]
In the aspect A, the apparatus includes a lubricant supply unit such as a lubricant application device 400 or 600 that supplies a lubricant to the latent image carrier by a lubricant supply member such as a brush roll 415. Based on the image area ratio of the toner image formed on the latent image carrier in the continuous image forming job and the deposit removal performance value calculated by the deposit removal performance value calculation means, during the continuous image formation job, The amount of lubricant to be supplied is determined, and the lubricant supply means is controlled so that the determined amount of lubricant is supplied during the continuous image forming job.
According to this, the frequency of interrupting the continuous image forming job for the refresh process can be reduced by suppressing the occurrence of filming that is the cause of the white spot abnormality image by increasing the amount of lubricant supplied to the latent image carrier. Can be reduced.

[Aspect C]
In the aspect B, the lubricant supply member is a rotating member such as a brush roll 415 to which a lubricant is attached, and the job interruption control unit controls the rotation speed of the rotating member to thereby supply the lubricant. Controlling the amount of lubricant supplied by the means.
According to this, increase / decrease in the amount of lubricant supplied to the latent image carrier can be easily controlled.

[Aspect D]
In the aspect C, the rotating member is a brush-like member such as a brush roll 415.
According to this, the lubricant can be satisfactorily supplied to the latent image carrier.

[Aspect E]
In any one of the above aspects B to D, the deposit removal performance value calculation unit estimates the cumulative amount of lubricant input to the cleaning member within a predetermined period such as the image forming period of the last 1000 sheets. Then, the deposit removal performance by the cleaning member is estimated according to the estimated accumulated amount.
According to this, it is possible to appropriately estimate the deposit removal performance according to the amount of wear of the cleaning member that changes according to the amount of lubricant input to the cleaning member.

[Aspect F]
In any one of the above aspects B to E, it has a leveling member 416, 616 for leveling the lubricant supplied to the latent image carrier by the lubricant supply means.
According to this, the lubricating effect by the lubricant supplied to the latent image carrier can be enhanced.

[Aspect G]
In the aspect F, the leveling member is a thermoplastic or thermosetting urethane blade.
According to this, the lubricant supplied to the latent image carrier can be leveled well.

[Aspect H]
In any one of the above aspects B to G, the lubricant is composed of a higher fatty acid.
According to this, a good lubricating effect can be obtained.

[Aspect I]
In any one of the above aspects A to H, the adhering matter removal performance value calculating means estimates a cumulative amount of toner input to the cleaning member within a predetermined period such as the image forming period of the last 1000 sheets. The deposit removal performance of the cleaning member is estimated according to the estimated accumulated amount.
According to this, it is possible to appropriately estimate the deposit removal performance according to the amount of wear of the cleaning member that changes according to the amount of toner input to the cleaning member.

[Aspect J]
In the above aspect I, the deposit removal performance value calculating means estimates the cumulative amount of toner input to the cleaning member from the cumulative image area of the image formed within a predetermined period. apparatus.
According to this, the amount of toner input to the cleaning member can be easily estimated.

DESCRIPTION OF SYMBOLS 101 Intermediate transfer belt 102 Image forming part 112 Transfer paper 201 Charging device 202 Photoconductor 203 Writing device 205 Development device 300 Photoconductor cleaner 331 Case 332 Fur brush 333 Entrance seal 334 Transfer roller 335 Cleaning blade 400, 600 Lubricant application device 411 Unit body member 412 Compression spring 414 Holder 415 Brush roll 416 Leveling member 420 Solid lubricant 500 Main body controller 512 Drive motor 520 Rotation control device 616 Blade member

JP 2006-235563 A JP 2011-170320 A

Claims (10)

By receiving the input of the image forming job, the latent image on the latent image carrier to be rotated is developed with toner by the developing means, and the resulting toner image is finally transferred onto the recording material, When receiving a continuous image forming job for continuously forming images on a plurality of recording materials, the continuous image forming job is interrupted when a predetermined interruption time arrives, and the development is performed during the interruption period. In an image forming apparatus for performing a cleaning process for rubbing the latent image carrier with a cleaning member while rotating the latent image carrier in a state where toner supply to the latent image carrier is prohibited by means,
The deposit removal performance value calculating means for calculating the deposit removal performance value by estimating the deposit removal performance by the cleaning member,
Upon receiving the input of the continuous image forming job, the image area ratio of the toner image formed on the latent image carrier in the continuous image forming job and the attached matter removing performance value calculated by the attached matter removing performance value calculating unit. And a job interruption control means for determining the interruption time of the continuous image forming job based on the above and performing the cleaning process during the interruption period of the continuous image forming job. The image forming apparatus according to claim 1.
Having a lubricant supply means for supplying a lubricant to the latent image carrier by a lubricant supply member;
The job interruption control means is based on the image area ratio of the toner image formed on the latent image carrier in the continuous image forming job and the deposit removal performance value calculated by the deposit removal performance value calculation means. Determining the amount of lubricant to be supplied during the continuous image forming job, and controlling the lubricant supply means so that the determined amount of lubricant is supplied during the continuous image forming job. An image forming apparatus. The image forming apparatus according to claim 2.
The lubricant supply member is a rotating member to which a lubricant is attached,
The image forming apparatus, wherein the job interruption control unit controls the amount of lubricant supplied by the lubricant supply unit by controlling a rotation speed of the rotating member. The image forming apparatus according to claim 3.
The image forming apparatus, wherein the rotating member is a brush-like member. The image forming apparatus according to any one of claims 2 to 4,
The deposit removal performance value calculating means estimates a cumulative amount of lubricant input to the cleaning member within a predetermined period, and estimates the deposit removal performance by the cleaning member according to the estimated cumulative amount. An image forming apparatus. The image forming apparatus according to any one of claims 2 to 5,
An image forming apparatus comprising a leveling member for leveling the lubricant supplied to the latent image carrier by the lubricant supply means. The image forming apparatus according to claim 6.
The image forming apparatus, wherein the leveling member is a thermoplastic or thermosetting urethane blade. The image forming apparatus according to any one of claims 2 to 7,
An image forming apparatus, wherein the lubricant comprises a higher fatty acid. The image forming apparatus according to any one of claims 1 to 8,
The deposit removal performance value calculating means estimates a cumulative amount of toner input to the cleaning member within a predetermined period, and estimates the deposit removal performance of the cleaning member according to the estimated cumulative amount. An image forming apparatus. The image forming apparatus according to claim 9.
The image forming apparatus according to claim 1, wherein the deposit removal performance value calculating unit estimates a cumulative amount of toner input to the cleaning member from a cumulative image area of an image formed within a predetermined period.