JP4592069B2 - Image forming apparatus - Google Patents

Description

The present invention, a copier, a printer, a facsimile, or relates to an image forming apparatus such as those of the MFP, and in particular relates to an image forming apparatus including a cleaning device having a cleaning blade.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a cleaning device that removes deposits such as toner adhered on an image carrier by a cleaning blade that abuts on the image carrier such as a photosensitive drum or a transfer belt. Are often used (see, for example, Patent Document 1).

  Patent Document 1 and the like disclose a technique for heating a cleaning blade based on a temperature drop in the vicinity of the cleaning blade in order to prevent the cleaning blade from being deformed due to deformation in a low temperature environment. .

  Specifically, in the vicinity of the cleaning blade, a sensor for detecting temperature and a heater are installed. When the sensor detects that the temperature in the vicinity of the cleaning blade has become equal to or lower than the reference temperature, the heater generates heat and raises the temperature in the vicinity of the cleaning blade.

JP-A-6-324612

  In the conventional technique described above, first, when the temperature of the cleaning blade rises to a predetermined temperature, there is a possibility that the cleaning blade may be caught in the image carrier.

  The cleaning blade is made of a rubber material such as polyurethane rubber, and the tip thereof is in contact with the image carrier at an optimum angle (cleaning angle) and contact pressure. Due to the characteristics of the rubber material, the cleaning blade malfunctions not only in a low temperature environment but also in a high temperature environment.

Specifically, when the temperature of the cleaning blade becomes a predetermined temperature or lower in a low temperature environment, the cleaning blade is cured and the optimum cleaning angle and contact pressure cannot be maintained. For this reason, a deposit such as untransferred toner adhered on the image carrier slips through the tip of the cleaning blade (the contact portion with the image carrier), resulting in poor cleaning.
On the other hand, when the temperature of the cleaning blade exceeds a predetermined temperature in a high temperature environment, the cleaning blade is softened and the optimum cleaning angle and contact pressure cannot be maintained. For this reason, the tip of the cleaning blade that comes into contact with the image carrier is caught in the image carrier in the traveling direction of the image carrier. In such a case, in addition to the occurrence of defective cleaning, abnormal noise due to entrainment occurs.

Secondly, the conventional technology may not be able to sufficiently prevent a cleaning failure when it suddenly changes to a low temperature environment.
In other words, since the heater for heating the cleaning blade is disposed away from the cleaning blade, the heater is heated after the sensor detects that the temperature in the vicinity of the cleaning blade is lower than the reference temperature. Responsiveness until the temperature of the cleaning blade itself was raised was insufficient.

  The problems as described above are various cleaning apparatuses used in the image forming apparatus, and are common to cleaning apparatuses having a cleaning blade. That is, a cleaning device that removes untransferred toner on the surface of a photoreceptor such as a photoreceptor belt or a photoreceptor drum, a transfer belt that transfers a toner image formed on the photoreceptor to a transfer material (recording medium), A cleaning device that removes deposits on the surface of a transfer member such as a transfer drum, or an intermediate that carries the toner image secondarily before transferring the toner image formed on the photoreceptor onto a transfer material (recording medium). This is a common problem with cleaning devices that remove deposits on the surface of intermediate transfer members such as transfer belts and intermediate transfer drums.

The present invention has been made in order to solve the above-described problems. An image forming apparatus in which a defect such as a cleaning defect is reliably suppressed without causing a defect of a cleaning blade even when an environmental change occurs. It is to provide.

According to a first aspect of the present invention, there is provided an image forming apparatus comprising: a cleaning device that includes a cleaning blade that contacts an image carrier and removes deposits attached to the image carrier; and the cleaning device and a transfer target A blower installed between the fixing unit for fixing the toner image on the material and configured to be able to switch the blowing direction, and the amount of deposits on the image carrier not removed by the cleaning blade are detected. An amount-of-attachment detection means; and a deformation amount detection means for detecting the amount of deformation of the cleaning blade, wherein the blower has a direction of blowing when the detection result of the amount-of-attachment detection means is a predetermined value or more is controlled from the side of the fixing portion so as to be directed to the side of the cleaning device, when the detection result of said deformation amount detecting means is a predetermined value or more, the feed In which the direction is controlled so as to be directed to the side of the fixing portion from the side of the cleaning device.

According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein the toner for forming a toner image on the image carrier has an average circularity of 0.90 to 0. .99 range.

According to a third aspect of the present invention, there is provided the image forming apparatus according to the first or second aspect , wherein the toner for forming a toner image on the image bearing member has a shape factor SF-1. Is in the range of 120 to 180, and the shape factor SF-2 is in the range of 120 to 190.

According to a fourth aspect of the present invention, in the image forming apparatus according to the first to third aspects, the toner for forming a toner image on the image carrier is a volume average. When the particle diameter is Dv μm and the number average particle diameter is Dn μm,
1.05 ≦ Dv / Dn ≦ 1.30
It is formed so that the following relationship is established.

An image forming apparatus according to a fifth aspect of the present invention is the image forming apparatus according to any one of the first to fourth aspects, wherein the cleaning device is provided close to the fixing portion.

An image forming apparatus according to a sixth aspect of the present invention is the image forming apparatus according to any one of the first to fifth aspects, wherein the image carrier is a photosensitive belt, a photosensitive drum, a transfer belt, or a transfer. At least one of a drum, an intermediate transfer belt, and an intermediate transfer drum is used.

  In the present application, the “process cartridge” refers to a charging unit that charges an image carrier, a developing unit that develops a latent image formed on the image carrier, and a cleaning device (cleaning device) that cleans the image carrier. Part) and an image carrier are defined as a unit that is integrated and detachable from the main body of the image forming apparatus.

In the present invention, the temperature of the cleaning blade is raised or lowered so that the temperature of the cleaning blade falls within a predetermined range. As a result, it is possible to provide an image forming apparatus in which defects such as a cleaning defect are reliably suppressed without causing a defect of the cleaning blade even when an environmental change occurs.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

Embodiment 1 FIG.
A first embodiment of the present invention will be described in detail with reference to FIGS.
First, the configuration and operation of the entire image forming apparatus will be described with reference to FIGS.
FIG. 1 is a block diagram showing a laser printer as an image forming apparatus, and FIG. 2 is an enlarged view showing an image forming unit thereof.

  As shown in FIG. 1, process cartridges 6Y, 6M, 6C, and 6K as image forming units corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged so as to face the intermediate transfer belt 8 of the intermediate transfer unit 15. It is installed side by side. The four process cartridges 6Y, 6M, 6C, and 6K installed in the apparatus main body 100 have substantially the same structure except that the toner colors used in the image forming process are different. The alphabet (Y, M, C, K) of the reference numerals for the photosensitive drum 1 and the primary transfer bias roller 9 is omitted.

  Referring to FIG. 2, the process cartridge 6 includes a photosensitive drum 1 as an image carrier, a charging unit 4, a developing unit 5, and a cleaning device (cleaning unit) 2 disposed around the photosensitive drum 1. Are integrated, and are configured to be detachable from the apparatus main body 100. Then, an image forming process (charging process, exposure process, developing process, transfer process, cleaning process, charge eliminating process) is performed on the photosensitive drum 1 to form a desired toner image on the photosensitive drum 1. It will be.

  In the first embodiment, the photosensitive drum 1, the charging unit 4, the developing unit 5, and the cleaning device 2 are integrated to form the process cartridge 6. However, the apparatus main body 100 includes each component as a single unit. It can also be installed detachably.

Referring to FIG. 2, the photosensitive drum 1 is rotationally driven in a clockwise direction in FIG. 2 by a drive unit (not shown). Then, the surface of the photosensitive drum 1 is uniformly charged at the position of the charging unit 4 (a charging process).
Thereafter, the surface of the photosensitive drum 1 reaches the irradiation position of the laser beam L emitted from the exposure unit 7 (see FIG. 1), and an electrostatic latent image is formed by exposure scanning at this position. (It is an exposure process.)

Thereafter, the surface of the photosensitive drum 1 reaches a position facing the developing unit 5, and the electrostatic latent image is developed at this position to form a desired toner image (developing process).
Specifically, the developing unit 5 contains a developer G composed of toner and a carrier. The developer G in the developing unit 5 is adjusted so that the ratio (toner concentration) of the toner in the developer G detected by the toner concentration sensor 57 falls within a predetermined range. That is, according to the consumption of toner in the developing unit 5, toner is supplied from the toner transport pipe 43 into the developer containing unit 54 through the toner supply port 44.

  The toner transport pipe 43 communicates with the corresponding toner bottle among the toner bottles 32Y, 32M, 32C, and 32K installed in the bottle container 31 above the apparatus main body 100 with reference to FIG. As a result, the respective color toners are conveyed from the toner bottles 32Y, 32M, 32C, and 32K containing the respective color toners to the respective developing units 5 via the toner conveyance pipes 43.

  Thereafter, the toner replenished in the developer accommodating portion 54 circulates through the two developer accommodating portions 53 and 54 while being mixed and stirred together with the developer G by the second conveying screw 56 and the first conveying screw 55. (This is a movement in the direction perpendicular to the paper surface of FIG. 2). The toner in the developer G is attracted to the carrier by frictional charging with the carrier, and is carried on the developing roller 51 together with the carrier by the magnetic force formed on the developing roller 51.

  The developer G carried on the developing roller 51 is conveyed in the direction of the arrow in FIG. 2 and reaches the position of the doctor blade 52. Then, after the developer G on the developing roller 51 is regulated to an appropriate amount at this position, the developer G is conveyed to a position facing the photosensitive drum 1 (developing area). The toner is attracted to the latent image formed on the photosensitive drum 1 by the electric field formed in the development area.

  After the development process described above, the surface of the photosensitive drum 1 reaches a position facing the intermediate transfer belt 8 and the first transfer bias roller 9, and the toner image on the photosensitive drum 1 is transferred to the intermediate transfer belt 8 at this position. Transferred upward (this is a primary transfer step). At this time, a small amount of untransferred toner (adhered matter) remains on the photosensitive drum 1.

Thereafter, the surface of the photoreceptor 1 reaches a position facing the cleaning device 2, and untransferred toner remaining on the photoreceptor drum 1 at this position is collected by the cleaning blade 2a (cleaning process). The cleaning blade 2a is made of a rubber material such as polyurethane rubber, and its tip is in contact with the photosensitive drum 1 at an optimal cleaning angle and contact pressure.
Finally, the surface of the photosensitive drum 1 reaches a position facing a neutralization unit (not shown), and the residual potential on the photosensitive drum 1 is removed at this position.
Thus, a series of image forming processes performed on the photosensitive drum 1 is completed.

  The image forming process described above is performed by each of the four process cartridges 6Y, 6M, 6C, and 6K. That is, referring to FIG. 1, laser light L based on image information is directed onto the photosensitive drums of the process cartridges 6Y, 6M, 6C, and 6K from the exposure unit 7 disposed below the process cartridge. Is irradiated. Specifically, the exposure unit 7 emits laser light L from a light source, and irradiates the photosensitive drum through a plurality of optical elements while scanning the laser light L with a polygon mirror that is rotationally driven. Thereafter, the toner images of the respective colors formed on the respective photosensitive drums through the developing process are transferred onto the intermediate transfer belt 8 in an overlapping manner. In this way, a color image is formed on the intermediate transfer belt 8.

  Here, referring to FIG. 1, the intermediate transfer unit 15 includes an intermediate transfer belt 8 as an image carrier, four primary transfer bias rollers 9Y, 9M, 9C, and 9K, a secondary transfer backup roller 12, and a counter roller. 13, a tension roller 14, a cleaning device 10, and the like. The intermediate transfer belt 8 is stretched and supported by the three roller members 12 to 14 and is endlessly moved in the direction of the arrow in FIG.

The four primary transfer bias rollers 9Y, 9M, 9C, and 9K respectively sandwich the intermediate transfer belt 8 with the photosensitive drums 1Y, 1M, 1C, and 1K to form a primary transfer nip. A transfer bias having a polarity opposite to the polarity of the toner is applied to the primary transfer bias rollers 9Y, 9M, 9C, and 9K.
The intermediate transfer belt 8 travels in the direction of the arrow and sequentially passes through the primary transfer nips of the primary transfer bias rollers 9Y, 9M, 9C, and 9K. In this way, the toner images of the respective colors on the photosensitive drums 1Y, 1M, 1C, and 1K are primarily transferred while being superimposed on the intermediate transfer belt 8.

  Thereafter, the intermediate transfer belt 8 (image carrier) onto which the toner images of the respective colors are transferred in an overlapping manner reaches a position facing the secondary transfer roller 19. At this position, the secondary transfer backup roller 12 sandwiches the intermediate transfer belt 8 with the secondary transfer roller 19 to form a secondary transfer nip. The color toner image formed on the intermediate transfer belt 8 is transferred onto a transfer material P such as transfer paper conveyed to the position of the secondary transfer nip. At this time, deposits such as untransferred toner that has not been transferred to the transfer material P remain on the intermediate transfer belt 8.

Thereafter, the intermediate transfer belt 8 as the image carrier reaches the position of the cleaning device 10 for the intermediate transfer belt 8. At this position, the untransferred toner (adhered matter) on the intermediate transfer belt 8 is collected. The cleaning device 10 is made of polyurethane rubber or the like, and includes a cleaning blade 10a that makes contact with the intermediate transfer belt 8 at a predetermined cleaning angle and contact pressure, a cleaning roller 10b such as a fur brush roller that makes sliding contact with the intermediate transfer belt 8, It has. Deposits on the intermediate transfer belt 8 are removed by the cleaning blade 10a and the cleaning roller 10b.
Thus, a series of transfer processes performed on the intermediate transfer belt 8 is completed.

Here, the transfer material P transported to the position of the secondary transfer nip is transported from a paper feed unit 26 disposed below the apparatus main body 100 via a paper feed roller 27, a registration roller pair 28, and the like. It has been done.
Specifically, a plurality of transfer materials P such as transfer paper are stored in the paper supply unit 26 in a stacked manner. When the paper feed roller 27 is rotated in the counterclockwise direction in FIG. 1, the uppermost transfer material P is fed between the rollers of the registration roller pair 28.

  The transfer material P conveyed to the registration roller pair 28 is temporarily stopped at the position of the roller nip of the registration roller pair 28 that has stopped rotating. Then, the registration roller pair 28 is rotationally driven in synchronization with the color image on the intermediate transfer belt 8, and the transfer material P is conveyed toward the secondary transfer nip. In this way, a desired color image is transferred onto the transfer material P.

Thereafter, the transfer material P on which the color image has been transferred at the position of the secondary transfer nip is conveyed to the position of the fixing unit 20. At this position, the color image transferred to the surface is fixed on the transfer material P by heat and pressure generated by the fixing roller and the pressure roller.
Thereafter, the transfer material P is discharged out of the apparatus through the rollers of the discharge roller pair 29. The transferred P discharged from the apparatus main body 100 by the discharge roller pair 29 is sequentially stacked on the stack unit 30 as an output image.
Thus, a series of image forming processes in the image forming apparatus is completed.

In the first embodiment, the average circularity is 0.90 to 0.99 as the toner in the developer accommodated in the developing unit 5 and the toner accommodated in the toner bottles 32Y, 32M, 32C, and 32K. A substantially spherical toner formed so as to be in the range of is used. As a result, it is possible to obtain a fine output image with less dust and good transferability and high image density reproducibility.
Here, the circularity of the toner particles is defined by the following equation.
Circularity = (perimeter of a circle having the same area as the projected area of the particle) / (perimeter of the projected particle image)
Therefore, when the circularity is 1.00, the toner particles have a true spherical shape. The average circularity of the toner can be typically measured using a flow type particle image measuring device “FPIA-2100” (manufactured by Toa Medical Electronics Co., Ltd.).

In the first embodiment, the shape factor SF-1 is in the range of 120 to 180 as the toner in the developer stored in the developing unit 5 and the toner stored in the toner bottles 32Y, 32M, 32C, and 32K. In this case, a substantially spherical toner formed so that the shape factor SF-2 is 120 to 190 is used. As a result, it is possible to suppress a decrease in cleaning performance while maintaining high transfer efficiency.
Here, the shape factor SF-1 indicates the sphericity of the toner particles, and is obtained by the following equation.
SF-1 = (M ² / S) × (100π / 4)
In the above equation, M is the maximum particle size (the largest particle size among sparse particle sizes) on the toner particle projection surface, and S is the area of the toner particle projection surface. Therefore, toner particles having a shape factor SF-1 of 100 are true spheres, and the sphericity decreases as the value increases from 100.

The shape factor SF-2 indicates the degree of unevenness of the toner particles, and is obtained by the following equation.
SF-2 = (N ² / S) × (100 / 4π)
In the above equation, N is the circumference of the toner particle projection surface, and S is the area of the toner particle projection surface. Therefore, the toner particles having the shape factor SF-2 of 100 have no irregularities, and the irregularities increase as the value increases from 100.
The shape factor SF-1 and the shape factor SF-2 are obtained by analyzing a toner particle photograph taken with a scanning electron microscope “S-800” (manufactured by Hitachi, Ltd.) and an image analyzer “LUSEX3” (manufactured by Nireco). )

In the first embodiment, the toner in the developer accommodated in the developing unit 5 and the toner accommodated in the toner bottles 32Y, 32M, 32C, and 32K have a volume average particle diameter of Dv μm and a number average particle diameter. Is Dn μm,
1.05 ≦ Dv / Dn ≦ 1.30
The one formed so that the relationship is established is used. As a result, the toner particles are selected according to the image pattern during the development process to maintain good image quality, and good developability is maintained even if the developing unit 5 is stirred for a long time.
The volume average particle diameter and number average particle diameter of the toner are typically measured by a coal counter type particle size distribution measuring device “Coulter Counter TA-2” (manufactured by Coulter Co.) or “Coulter Multisizer 2” (Coulter). Can be used.

  Next, the configuration and operation of the cleaning apparatuses 2 and 10 that are characteristic of the first embodiment will be described in detail with reference to FIGS. FIG. 3 is a partially enlarged view showing the vicinity of the cleaning device 10 for the intermediate transfer belt 8.

As shown in FIG. 2, a temperature sensor 60 as temperature detecting means and a Peltier element 61 are disposed on the cleaning blade 2 a in the cleaning device 2 for the photosensitive drum 1.
The temperature sensor 60 detects the temperature of the cleaning blade 2 a and transmits the detection result to the control unit 70.

  The Peltier element 61 is configured to be able to turn on and off the input of current to the junction of two kinds of metals and to switch the current direction. Thereby, when a current is passed in a predetermined current direction, the Peltier element 61 functions as a heating means for heating the cleaning blade 2a. On the other hand, when a current is passed in the opposite current direction, the Peltier element 61 functions as a cooling means for cooling the cleaning blade 2a.

  Specifically, when the temperature sensor 60 detects that the temperature of the cleaning blade 2a is equal to or lower than the lower limit value of the predetermined range, the control unit 70 causes the Peltier element 61 to function as a heating unit based on the detection result. To control. As a result, the cleaning blade 2a is heated to prevent the cleaning blade 2a from being hardened, and deposits such as untransferred toner adhering to the photosensitive drum 1 are adhered to the tip of the cleaning blade 2a (with the photosensitive drum 1). This prevents the occurrence of defective cleaning due to slipping through the contact portion.

  On the other hand, when the temperature sensor 60 detects that the temperature of the cleaning blade 2a is equal to or higher than the upper limit of the predetermined range, the control unit 70 causes the Peltier element 61 to function as a cooling unit based on the detection result. To control. Thereby, the cleaning blade 2a is cooled, the softening of the cleaning blade 2a is suppressed, and the trouble that the cleaning blade 2a is caught in the photosensitive drum 1 is prevented.

  In the first embodiment, the temperature of the cleaning blade 2a is controlled to be within a predetermined range by using one Peltier element 61 that functions as a heating unit and a cooling unit. On the other hand, it is also possible to control the temperature of the cleaning blade 2a within a predetermined range using a Peltier element that functions only as a heating means and a Peltier element that functions only as a cooling means.

  In the first embodiment, the temperature sensor 60 is installed on the cleaning blade 2a, and the temperature of the cleaning blade 2a is directly detected. On the other hand, the temperature sensor 60 can be installed in the vicinity of the cleaning blade 2a to indirectly detect the temperature of the cleaning blade 2a.

  As shown in FIG. 3, on the cleaning blade 10a in the cleaning device 10 for the intermediate transfer belt 8, a heater 62 that functions as a heating unit, a cooler 63 that functions as a cooling unit, and a temperature sensor (not shown). ) And are arranged. Further, a photosensor 64 as an adhering amount detection unit is disposed at a position facing the intermediate transfer belt 8.

  The photosensor 64 optically detects the amount of deposits such as untransferred toner that are not removed by the cleaning device 10 (cleaning blade 10a). Specifically, the photosensor 64 includes a light emitting element such as a laser diode and a light receiving element such as a photodiode. The photosensor 64 irradiates the light emitted from the light emitting element onto the intermediate transfer belt 8 and receives the reflected light amount received by the light receiving element. Detect the amount of deposits. A detection result relating to the amount of deposit detected by the photosensor 64 is transmitted to the control unit 70.

The heater 62 is configured to be able to switch input power on and off. Thus, when the heater 62 is turned on, the heater 62 functions as a heating unit that heats the cleaning blade 10a.
The cooler 63 is also configured to be able to switch input power on and off. Thereby, when the cooler 63 is turned on, the cooler 63 functions as a cooling means for cooling the cleaning blade 10a.

  Specifically, when the photo sensor 64 detects that the amount of deposits on the intermediate transfer belt 8 is greater than or equal to a predetermined value and is likely to cause a cleaning failure, the controller 70 heats the heater 62 based on the detection result. Control to function as a means. As a result, the cleaning blade 10a is heated, and the curing of the cleaning blade 10a is suppressed, and deposits such as non-transferred toner adhering to the intermediate transfer belt 8 pass through the tip of the cleaning blade 10a, resulting in poor cleaning. The trouble to do is prevented.

  On the other hand, when the temperature sensor (not shown) detects that the temperature of the cleaning blade 10a is equal to or higher than a predetermined value, the controller 70 causes the cooler 63 to function as a cooling unit based on the detection result. Control. As a result, the cleaning blade 10a is cooled, and the problem of the cleaning blade 10a being caught in the intermediate transfer belt 8 is prevented.

  As described above, in the first embodiment, the temperature of the cleaning blades 2a, 10a is adjusted by increasing / decreasing the temperature so that the temperature of the cleaning blades 2a, 10a falls within a predetermined range. Thereby, even if the environmental change occurs, it is possible to surely prevent problems such as the cleaning blades 2a and 10a being caught and defective cleaning.

Embodiment 2. FIG.
A second embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 4 is a cross-sectional view showing the vicinity of the transfer belt of the image forming apparatus according to the second embodiment. FIG. 5 is a partially enlarged view showing the vicinity of the cleaning device facing the transfer belt of FIG. The second embodiment is mainly characterized in that the transfer belt 88 is disposed on the main body of the image forming apparatus and the cleaning device 10 for removing deposits attached to the transfer belt 88 is disposed. It differs from one.

  As shown in FIG. 4, the photosensitive drums 1Y, 1M, 1C, and 1K of the image forming units corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged in parallel so as to face the transfer belt 88 of the transfer belt unit 80. It is installed. Although not shown, a charging unit, a developing unit, a cleaning device, and a charge eliminating unit are disposed around each of the photosensitive drums 1Y, 1M, 1C, and 1K, as in the first embodiment.

  The transfer belt unit 80 includes a transfer belt 88 as an image carrier, four transfer bias rollers 9Y, 9M, 9C, and 9K, four backup rollers 11Y, 11M, 11C, and 11K, a counter roller 81, and a plurality of roller members 82˜. 86, a suction roller 90, a cleaning device 10 and the like. The transfer belt 88 is stretched and supported by a plurality of roller members 82 to 86 and a counter roller 81, and is moved endlessly in the direction of the broken arrow in FIG. One roller member 83 among the plurality of roller members 82 to 86 functions as a tension roller that abuts the outer peripheral surface of the transfer belt 88 with a predetermined spring force.

The four transfer bias rollers 9Y, 9M, 9C, and 9K sandwich the transfer belt 88 between the photosensitive drums 1Y, 1M, 1C, and 1K to form a transfer nip.
The transfer belt 88 travels in the direction of the broken line arrow and conveys the transfer material P in the direction of the solid line arrow. The material P to be transferred conveyed to the transfer belt 88 is fed from a paper feeding unit (not shown) and fed from between the suction roller 90 and the fixing belt 88, and then the transfer bias rollers 9Y, 9M, and 9C. , And 9K transfer nip sequentially. Thus, the toner images of the respective colors on the photosensitive drums 1Y, 1M, 1C, and 1K are transferred onto the transfer material P in an overlapping manner. The backup rollers 11Y, 11M, 11C, and 11K are installed to maintain the transfer nip between the photosensitive drums 1Y, 1M, 1C, and 1K and the transfer belt 88 with high accuracy.

Thereafter, the transfer material P onto which the toner images of the respective colors are transferred in an overlapping manner is separated from the transfer belt 88 and conveyed to the position of the fixing unit 20. At this position, the color image transferred to the surface is fixed on the transfer material P by heat and pressure generated by the fixing belt and the pressure roller.
Thereafter, the transfer material P is discharged out of the apparatus, and a series of image forming processes is completed.

On the other hand, the surface of the transfer belt 88 after the transfer material P is separated reaches the position of the cleaning device 10 for the transfer belt 88. At this position, deposits such as untransferred toner on the transfer belt 88 are collected. The cleaning device 10 includes a cleaning blade 10 a made of polyurethane rubber or the like that contacts the transfer belt 88 with a predetermined cleaning angle and contact pressure, and a cleaning roller 10 b that slides on the transfer belt 88. Deposits on the transfer belt 88 are removed by the cleaning blade 10a and the cleaning roller 10b. On the transfer belt 88, a toner image for sampling is formed at a predetermined timing in order to optimally adjust and control the image density. The image density of this sampling toner image is detected by a photosensor (not shown) facing the transfer belt 88 as an image carrier.
Thus, a series of transfer processes performed on the transfer belt 88 is completed.

  Here, as shown in FIG. 5, on the cleaning blade 10a in the cleaning device 10 for the transfer belt 88, a heat pipe 68 functioning as a cooling means, a strain sensor 67 as a deformation amount detecting means, and a temperature sensor ( (Not shown). In addition, a heater 69 that functions as a heating unit is disposed inside the opposing roller 81. Further, a fan 65 (blower) functioning as a heating unit and a cooling unit is disposed between the fixing unit 20 and the cleaning device 10.

  The strain sensor 67 detects that the amount of deflection of the cleaning blade 10 a exceeds a predetermined value, and detects the winding of the cleaning blade 10 a with respect to the transfer belt 88. The detection result detected by the strain sensor 67 is transmitted to the control unit 70.

  The heat pipe 68 is a planar heat pipe, and is moved by the drive unit 95 so as to be able to contact with and separate from the cleaning blade 10a as an object to be cooled. Thus, when the heat pipe 68 comes into contact with the cleaning blade 10a, the heat pipe 68 functions as a cooling means for cooling the cleaning blade 10a.

  The heater 62 provided in the facing roller 69 is configured to be able to switch on / off of input power. Thereby, when the heater 69 is turned on, the heater 69 functions as a heating means for heating the cleaning blade 10a. In the second embodiment, since the heater 69 is not directly installed on the cleaning blade 10a, the heating efficiency is lower than when the heater 69 is installed directly, but the installation space for the heater 69 is placed on the cleaning blade 10a. This is effective when it cannot be secured.

Further, not only the heating means but also the cooling means, if the installation space on the cleaning blade 10a cannot be secured, the heating means or the cooling means are provided on the cleaning roller 10b, the roller member 83, etc. that are provided close to the cleaning blade 10a. It can also be arranged.
In the second embodiment, since the cleaning device 10 is located close to the fixing unit 20, the temperature of the cleaning blade 10a can be kept relatively high. Therefore, the load on the heating means for raising the temperature of the cleaning blade 10a is reduced.

  The fan 65 as a blower disposed between the fixing unit 20 and the cleaning device 10 is configured to be able to switch the blowing direction by reversing the rotation direction of the wings. Accordingly, when the blowing direction of the fan 65 is changed from the fixing unit 20 side to the cleaning device 10 side, the fan 65 sends heat generated in the fixing unit 20 to the cleaning device 20 as heating means for heating the cleaning blade 10a. Function. On the other hand, when the blowing direction of the fan 65 is changed from the cleaning device 10 side to the fixing unit 20 side, the fan 65 convects the heat generated in the cleaning device 10 to the fixing unit 20 side and cools the cleaning blade 10a. Functions as a cooling means.

  When the fan 65 is located away from the fixing unit 20 and close to the cleaning device 10, the fan 65 moves to the cleaning device 20 when the fan 65 is directed toward the cleaning device 10. It functions as a cooling means for sending cold air to cool the cleaning blade 10a.

  Specifically, when the distortion sensor 67 detects a state in which the cleaning blade 10 a is likely to be caught in the transfer belt 8, the control unit 70 controls the drive unit 95 based on the detection result to heat pipe 68. Is moved to function as a cooling means. Furthermore, the control unit 70 controls the fan 65 to function as a cooling unit. Thereby, the cleaning blade 10a is cooled, and the trouble that the cleaning blade 10a is caught in the transfer belt 88 is prevented.

  On the other hand, when the temperature sensor (not shown) detects that the temperature of the cleaning blade 10a is equal to or lower than a predetermined value, the control unit 70 uses the heater 69 and the fan 65 as heating means based on the detection result. Control to do. As a result, the cleaning blade 10a is heated, and the adhering matter adhering to the transfer belt 88 slips through the tip of the cleaning blade 10a, thereby preventing the occurrence of defective cleaning.

  As described above, also in the second embodiment, the temperature of the cleaning blade 10a is adjusted by increasing / decreasing the temperature so that the temperature of the cleaning blade 10a falls within a predetermined range. As a result, even if the environment changes, it is possible to reliably prevent problems such as the cleaning blade 10a being involved and defective cleaning.

  It should be noted that the present invention is not limited to the above-described embodiments, and within the scope of the technical idea of the present invention, the embodiments can be modified as appropriate in addition to those suggested in the embodiments. Is clear. In addition, the number, position, shape, and the like of the constituent members are not limited to the above embodiments, and can be set to a number, position, shape, and the like that are suitable for carrying out the present invention.

1 is an overall configuration diagram illustrating an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view showing the vicinity of a photosensitive drum cleaning device in the image forming apparatus of FIG. 1. FIG. 2 is a partially enlarged view showing the vicinity of a cleaning device for an intermediate transfer belt in the image forming apparatus of FIG. 1. It is sectional drawing which shows the transfer belt vicinity of the image forming apparatus in Embodiment 2 of this invention. FIG. 5 is a partially enlarged view showing the vicinity of the transfer belt cleaning device of FIG. 4.

Explanation of symbols

1, 1Y, 1M, 1C, 1K photosensitive drum (image carrier),
2 cleaning device,
2a cleaning blade, 2b cleaning roller,
6, 6Y, 6M, 6C, 6K process cartridge (imaging part),
8 Intermediate transfer belt,
9, 9Y, 9M, 9C, 9K primary transfer bias roller,
10 Cleaning device,
10a cleaning blade, 10b cleaning roller,
13 counter roller, 15 intermediate transfer unit, 20 fixing unit,
60 temperature sensor (temperature detection means),
61 Peltier elements (heating means, cooling means), 62 heaters, 63 coolers, 64 photosensors (attachment amount detection means), 65 fans (blowers),
67 strain sensor (deformation amount detection means), 68 heat pipe,
69 heater (heating means), 70 controller,
80 transfer belt unit, 81 facing roller, 81-86 roller member,
88 transfer belt, 90 suction roller, 95 drive unit,
100 Image forming apparatus main body (apparatus main body).

Claims (6)

A cleaning device provided with a cleaning blade that contacts the image carrier and removes deposits attached to the image carrier;
A blower that is installed between the cleaning device and a fixing unit that fixes a toner image on a transfer material, and is configured to be capable of switching a blowing direction;
A deposit amount detection means for detecting the amount of deposit on the image carrier that is not removed by the cleaning blade;
Deformation amount detecting means for detecting the deformation amount of the cleaning blade;
With
The blower is
The attachment when the amount detection means of the detection result is a predetermined value or more, the blowing direction is controlled so as to be directed from the side of the fixing portion on the side of the cleaning device,
Detection If the result is equal to or greater than a predetermined value, an image forming apparatus wherein the air blowing direction and said controlled is that to face the side of the fixing portion from the side of the cleaning apparatus of the deformation amount detecting means. 2. The image forming apparatus according to claim 1, wherein the toner for forming a toner image on the image carrier is formed so that an average circularity is in a range of 0.90 to 0.99. . The toner for forming a toner image on the image carrier is formed so that the shape factor SF-1 is in the range of 120 to 180 and the shape factor SF-2 is in the range of 120 to 190. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The toner for forming a toner image on the image carrier has a volume average particle diameter of Dv μm and a number average particle diameter of Dn μm.
1.05 ≦ Dv / Dn ≦ 1.30
The image forming apparatus according to claim 1, wherein the image forming apparatus is formed so that The image forming apparatus according to claim 1, wherein the cleaning device is disposed close to the fixing unit. 6. The image bearing member according to claim 1, wherein the image carrier is at least one of a photoreceptor belt, a photoreceptor drum, a transfer belt, a transfer drum, an intermediate transfer belt, and an intermediate transfer drum. The image forming apparatus described.

Images