JP2007086591A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To execute a sure and uniform cleaning by preventing peeling up in both ends of a cleaning blade due to a difference in temperature on both ends of the cleaning blade brought into a sliding contact with an image carrier. <P>SOLUTION: The image forming apparatus which cleans toner remaining on an image carrier 1 with the blade 81 is provided with: a frictional force detecting means 8A for detecting frictional force in both ends where surrounding of both ends on an outer periphery of the image carrier 1 and the blade 81 is brought into the sliding contact; and a frictional force varying means 8B for varying the frictional force between the image carrier 1 and the blade 81. When the frictional force between the image carrier 1 and both ends of the blade 81 is detected to be uneven by the frictional force detecting means 8A, one of the frictional forces on both ends of the blade 81 is varied by the frictional force varying means 8B and control is carried out so that the frictional force over the whole length of the blade 81 may be uniform. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multi-function machine having a plurality of these functions, and more particularly, to image formation using a cleaning blade in a cleaning device for cleaning residual toner on an image carrier. Relates to the device.

  In general, in an image forming apparatus using an electrophotographic process or the like, an electrostatic latent image corresponding to a document screen is formed on the surface of an image carrier (photosensitive member) charged to a predetermined potential, and a visible image ( Toner image) is formed. The toner image formed on the photoconductor reaches the transfer unit by the rotation of the photoconductor, and is transferred to the transfer material conveyed to the transfer unit. The toner image transferred to the transfer material is fixed to the transfer material by the fixing unit. After the toner image is transferred, residual toner on the photoconductor is removed by a cleaning device arranged at a predetermined position around the photoconductor.

  In an image forming apparatus in which a cleaning blade is pressed against a rotating photoreceptor surface in a counter form to clean toner remaining on the photoreceptor, turning is generated by friction between the photoreceptor and the cleaning blade.

  In order to prevent the cleaning blade from turning over, the image forming apparatus disclosed in Patent Document 1 uses a laser to remove a portion of the drum surface excluding a contact portion with which a peeling claw contacts, when forming a belt-like toner image on the surface of the photosensitive drum. The exposure is selectively performed by an exposure device, and the exposed portion is developed by a developing device.

  In the image forming apparatus disclosed in Patent Document 2, the edge portion of the cleaning blade outside the image forming region is chamfered with heat to reduce the friction at the end portion.

  The image forming apparatus of Patent Document 3 has a temperature adjustment mechanism that adjusts the temperature of the region where the cleaning blade contacts the rotating member, and sets the set temperature by the temperature adjusting mechanism according to the number of rotations of the rotating member per fixed time. To change.

  The image forming apparatus of Patent Document 4 includes a detection unit that detects a temperature around the image carrier, and at least a non-image portion of the image carrier on which an electrostatic latent image is not formed according to the temperature detected by the detection unit. Part of the toner is attached from the developing device.

The image forming apparatus disclosed in Patent Document 5 includes an image forming apparatus including a plurality of image forming units. The image forming apparatus includes a cooling unit in a cleaning device close to the fixing device, and a plurality of cooling units in the main scanning direction. The temperature is made uniform.
JP-A-8-6441 Japanese Patent Laid-Open No. 11-73072 Japanese Patent No. 3530736 JP 2001-356642 A JP-A-4-369678

  In order to prevent the counter type cleaning blade from turning up, in Patent Document 1, toner is forcibly supplied to the cleaning blade or a lubricant is supplied. Further, when the temperature of the cleaning blade rises, the torque with the image carrier increases due to the change in rubber characteristics, and the probability of turning up increases. In recent years, the particle size of toner tends to be reduced to improve the image quality. To cope with this, the use of a rubber material having high rebound resilience is particularly likely to be turned up at high temperatures in order to improve the cleanability at low temperatures. For this reason, in Patent Document 4, it is often performed to arrange the fans and ducts at appropriate positions in the machine so as to reduce the temperature rise of the cleaning blade as much as possible to avoid the above problems.

  Although these measures greatly reduce the probability of turning the cleaning blade, the above-mentioned problem may occur suddenly as image formation continues. This is partly because the frictional force of the cleaning blade in the main scanning direction is unbalanced. When the frictional force becomes unbalanced, the cleaning blade is twisted in the main scanning direction, and the setting conditions (contact angle, etc.) with respect to the image carrier change in the main scanning direction. When the frictional force becomes imbalanced, the torsion is maximized, and turning is likely to occur from the end portion having the larger frictional force. Reasons for the frictional force to be unbalanced include bias in processing accuracy (length, angle, etc.) of the cleaning blade in the main scanning direction, imbalance in the printing rate on the image carrier in the main scanning direction, and temperature rise imbalance in the main scanning direction. There is.

  In Patent Document 2, the end of the cleaning blade is chamfered to reduce friction at the end, thereby preventing abnormal noise and chipping of the cleaning blade. It does not eliminate the turning of the blade.

  In Patent Document 3, a temperature adjustment mechanism that adjusts the temperature of a region where the cleaning blade contacts the image carrier is arranged inside the image carrier, and does not eliminate the frictional force imbalance at both ends of the cleaning blade. Absent.

  In the specification of Patent Document 5, it is described that the temperature is made uniform with a plurality of fans. In addition, there was an invention in which a heat pipe was attached in the vicinity of the cleaning blade to equalize the heat, but the temperature balance error was merely reduced, and it was not a drastic measure.

  In order to solve these problems, the cleaning blade is required to have high processing accuracy, or the main scanning direction printing rate is stored in a large-capacity memory, and the main scanning direction toner supply amount (toner band of the toner band) to the cleaning blade accordingly. Width) and the like, and the duct is complicatedly wound in the machine to suppress the temperature rise, so that the freedom of layout in the machine is reduced. These can reduce the probability of sudden turning of the cleaning blade. However, since the state of the cleaning blade is not detected, the turning is not controlled and a margin for turning is not secured.

  The present invention prevents the turning of the cleaning blade due to the difference in the rubber characteristics at both ends of the cleaning blade due to the temperature difference between the both ends of the cleaning blade that is in sliding contact with the image carrier, and performs reliable and uniform cleaning. It is the purpose.

  The above object is solved by the image forming apparatus described below of the present invention.

  (1) In the image forming apparatus of the present invention, after the electrostatic latent image formed on the image carrier is developed with toner in the developing device and transferred to a transfer material, the toner remaining on the image carrier In an image forming apparatus that cleans the image with a cleaning blade, frictional force detecting means for detecting a frictional force at both ends of the outer peripheral surface of the image carrier and both ends where the cleaning blade is in sliding contact, the image carrier and the image carrier Frictional force changing means for changing the frictional force with the cleaning blade, and the frictional force detecting means detects that the frictional forces at both ends of the image carrier and the cleaning blade are unbalanced. The frictional force changing means changes the frictional force of each part of the cleaning blade so that the frictional force over the entire length of the cleaning blade is uniform. It is characterized in that the control.

  (2) In the image forming apparatus according to the aspect of the invention, in (1), the frictional force changing unit performs control so as to change a frictional force on one end side of the both ends of the cleaning blade. It is a feature.

  (3) In the image forming apparatus of the present invention, in (1) or (2), the frictional force detecting means is provided in the vicinity of both ends of the outer peripheral surface parallel to the rotation axis direction of the cleaning blade or the image carrier. It is a means for detecting a frictional force between the cleaning blade and the image carrier, which is disposed in contact with or near the both end portions.

  (4) In the image forming apparatus of the present invention, in (1) or (3), the frictional force detection means is disposed in the vicinity of both ends of the cleaning blade in the longitudinal direction parallel to the rotation axis direction of the image carrier. This is a vibration sensor.

  (5) In the image forming apparatus of the present invention, in any one of (1) to (4), the frictional force detecting means is arranged in a longitudinal direction parallel to the rotational axis direction of the image carrier of the cleaning blade. It is a temperature sensor arranged near both ends.

  (6) In the image forming apparatus of the present invention, in (1), the frictional force changing means is provided on a developing device on at least a part of the non-image forming portion on the image carrier where an electrostatic latent image is not formed. Thus, the toner is attached to form a belt-like toner image.

  (7) In the image forming apparatus of the present invention, in (1), the frictional force changing means is a lubricant on at least a part of the non-image forming portion on the image carrier where an electrostatic latent image is not formed. It is a means to apply | coat.

  (8) The image forming apparatus of the present invention is characterized in that, in (1), the frictional force changing means is a temperature changing means for changing a temperature of a contact portion between the cleaning blade and the image carrier. To do.

  (9) In the image forming apparatus of the present invention, in any one of (6) to (8), the frictional force changing unit continuously changes in a longitudinal direction parallel to the rotation axis direction of the image carrier. Thus, the frictional force is controlled as described above.

  (10) In the image forming apparatus of the present invention, after the electrostatic latent image formed on the image carrier is developed with the toner in the developing device and transferred to the transfer material, the toner remaining on the image carrier In an image forming apparatus that cleans the image with a cleaning blade, frictional force detecting means for detecting a frictional force at both ends of the outer peripheral surface of the image carrier and both ends where the cleaning blade is in sliding contact, the image carrier and the image carrier Friction force changing means for changing the friction force with the cleaning blade, and a friction force detection signal from the friction force detection means, the cleaning blade and the vicinity of one end in the rotation axis direction of the outer peripheral surface of the image carrier Friction force comparison means for comparing the friction force in the vicinity of the other end, and the friction force comparison means compares the output from the friction force detection means by the control means. And it is characterized in and.

  (11) The image forming apparatus of the present invention is characterized in that, in (10), the frictional force changing means is operated by a signal from the frictional force comparing means.

  (12) In the image forming apparatus of the present invention, in (10), the frictional force changing unit does not form an electrostatic latent image on the image carrier by a frictional force detection signal from the frictional force detecting unit. The toner is attached to at least a part of the image area from the developing device.

  (13) In the image forming apparatus of the present invention, the electrostatic latent image formed on the rotating image carrier is developed with toner in the developing device and transferred to the intermediate transfer member, and then remains on the intermediate transfer member. In the image forming apparatus for cleaning the toner to be cleaned by a cleaning blade, friction force detecting means for detecting a friction force at both ends of the outer peripheral surface of the intermediate transfer member and both ends where the cleaning blade is in sliding contact, and the intermediate transfer Frictional force changing means for changing the frictional force between the body and the cleaning blade, and the frictional force detecting means is that the frictional force at both ends of the intermediate transfer body and the cleaning blade is unbalanced. When detected, the frictional force changing means is provided for each part of the cleaning blade so that the frictional force over the entire length of the cleaning blade is uniform. It is characterized in that the control to change the friction force.

  As described above in detail, according to the present invention, the frictional resistance between the surface of the image carrier and the cleaning blade at the end of the image carrier is made uniform, the turning of both ends of the cleaning blade in the main scanning direction, and the cleaning blade It was possible to stably provide a cleaning blade excellent in durability by preventing edge chipping and abnormal noise generation of the cleaning blade. As a result, it is possible to provide an image forming apparatus that stably forms an image with high image quality and high reliability.

  Embodiments of the present invention will be described below. The description in this column does not limit the technical scope of the claims or the meaning of terms.

[Image forming apparatus]
FIG. 1 is an overall configuration diagram of an image forming apparatus including an image forming apparatus main body A, an image reading apparatus SC, and an automatic document feeder DF.

  The illustrated image forming apparatus main body A includes an image forming unit including an image carrier 1, a charging unit 2, an image exposing device 3, a developing unit 4, a transfer unit 5, a charge eliminating unit 6, a separation claw 7, a cleaning unit 8, and the like. The fixing device 9 and a paper transport system are included.

  The paper transport system includes a first transport unit including a paper feed cassette 10, a first paper feed unit 11, a second paper feed unit 12, a transport unit 13, a paper discharge unit 14, and a manual paper feed unit 15; It is composed of a circulation refeeding unit for recirculation refeeding.

  The paper feed cassette 10 and the first paper feed means 11 are formed by a plurality of paper feed means (three stages in the figure), and accommodate and feed a plurality of types of paper P. The paper size is input by manual setting by the operation unit 21 or automatic paper size setting by the paper size detecting means.

  The sheet P that has passed through the conveying means 13 and has been fixed by the fixing device 9 is conveyed by the conveying path switching means 16 so that the straight discharge path conveying path r1, the reverse discharging path conveying path r2, and the double-sided circulation path conveying path. One of r3 is selected and conveyed.

  The paper P passing through the transport path r1 is discharged with the image forming surface facing up (face up). The paper P passing through the transport path r2 advances to the transport paths r3 and r4 of the double-sided circulation path, and is then transported in reverse, passes through the transport path r2, and is discharged with the image forming surface facing down (face down). .

  The second transport unit branches the paper P on which the image has been formed by the image forming unit, before the paper discharge unit 14 by the transport path switching unit 16, transports the paper P along the circulation refeeding path, and recirculates the paper. The paper P is reversed by the reverse conveying roller 17 in the middle of the paper path, and then fed again to the image forming unit via the second paper feeding unit 12.

  The document d placed on the document table of the automatic document feeder DF is transported by the paper feeding means, and one or both side images of the document d are read by the optical system of the image reading device SC and read by the image sensor CCD. It is. The analog signal photoelectrically converted by the image sensor CCD is subjected to analog processing, A / D conversion, shading correction, image compression processing and the like in the image processing unit 20 and then sent to the image exposure apparatus 3.

  In the image exposure apparatus 3, the output light from the semiconductor laser is irradiated to the image carrier 1 of the image forming unit to form a latent image. In the image forming unit, processes such as charging, exposure, development, transfer, separation, and cleaning are performed. An image is transferred by the transfer means 5 on the paper P fed from the paper feed cassette 10 and the manual paper feed means 15. The paper P carrying the image is fixed by the fixing device 9 and discharged from the paper discharge means 14.

  Alternatively, the single-sided image processed paper P sent to the circulation refeed unit by the conveyance path switching unit 16 is reversed by the reverse conveyance roller 17 and then subjected to double-sided image processing in the image forming unit, and then fixed by the fixing device 9. The paper is processed and discharged by the paper discharge means 14.

[Cleaning device]
FIG. 2 is a sectional view of the cleaning device 8.

  In the figure, reference numeral 81 denotes a cleaning blade (hereinafter referred to as a blade) made of an elastic material, which peels off transfer residual toner remaining on the image carrier 1 after transfer from the image carrier 1. The tip of the blade 81 is in pressure-contact with the outer peripheral surface of the rotating image carrier 1 on the upstream side of the vertical upper position that is the antigravity direction of the rotation center of the image carrier 1.

  The blade 81 is made of polyurethane rubber or silicone rubber having moderate elasticity.

  The blade 81 is pressed by the weight 84 held at the other end of the blade support member 82 that holds the blade 81, and comes into pressure contact with the image carrier 1. Alternatively, the other end of the blade support member 82 is urged by a coil spring (not shown) and presses the tip of the blade 81 against the image carrier 1.

  The assembly unit including the blade 81, the blade support member 82, and the weight 84 rotates about the rotation shaft body 85 as a rotation center, and presses the blade 81 against the image carrier 1.

  The untransferred toner peeled off by the blade 81 is collected by the illustrated counterclockwise rotation of the guide roller 86 disposed below the blade 81 and conveyed in the direction of the toner conveying screw 87.

  The brush-shaped guide roller 86 and the spiral-shaped toner conveying screw 87 are rotatably supported at a predetermined position of the housing 83 and are rotated by a driving unit (not shown).

  The transfer residual toner transported by the toner transport screw 87 is transported to the developing device 4 via a toner recycle device (not shown) or is transported to a waste toner box (not shown) and collected.

  The cleaning device 8 of the present invention includes a friction force detection means 8A, a friction force change means 8B, and a friction force comparison means 8C.

  The frictional force detection means 8 </ b> A detects the frictional force at both ends of the blade 81 in the main scanning direction. The frictional force changing means 8B changes the frictional force at either end when the frictional force is unbalanced at both ends of the blade 81, and the frictional force in the main scanning direction of the blade 81 is always substantially the same. Control to be. The frictional force comparison means 8C compares the frictional force of one end and the other end of the blade 81 in the main scanning direction.

[Cleaning blade friction force detection means]
For detecting the frictional force, the vibration and temperature of the blade 81 are used. The frictional force detecting means 8A has a vibration measurement by the vibration sensor S1 in contact with the rubber portions near the edge portions at both ends in the main scanning direction of the blade 81, or a temperature by the temperature sensor S2 in contact with or near the same place. Use measurement.

  Indirectly, the frictional force can be detected without changing the behavior of the blade 81 and affecting the cleaning performance. Although the displacement sensor may be brought into contact with the blade 81, it is necessary to pay attention to the arrangement and contact method of the sensor because the behavior of the blade 81 is disturbed and the possibility of affecting the cleaning performance is increased. In a general optical sensor combining a light emitting diode (LED) and a phototransistor or a photodiode, it is difficult to accurately detect the amount of displacement when the frictional force is high and the blade 81 is slightly displaced. Although detection can be performed using a laser, the sensor itself becomes large-scale, resulting in a significant increase in cost and size of the apparatus.

  In vibration measurement, if the vibration amplitude is monitored and the average value within a certain unit time (for example, 1 second) is set as the amplitude at that time, the average amplitude value can be indirectly set as the frictional force. In temperature measurement, by monitoring the frictional heat, the temperature at that time can be indirectly set as the frictional force.

  In general, the blade 81 is made of an elastic material such as urethane rubber. However, when the frictional force is increased, the abutment to the surface of the image bearing member that occurs when the tip of the blade 81 is turned up and the springing and returning movement due to the elasticity are increased and vibration is increased. . If this vibration is detected using the vibration sensor S1 or the like, the frictional force can be indirectly detected.

  It is a well-known fact that frictional heat is generated where there is friction. If the temperature near the edge of the blade 81 in contact with the image carrier 1 is detected using the temperature sensor S2 or the like, the frictional force can be detected indirectly. By installing the frictional force detecting means 8A such as the vibration sensor S1 and the temperature sensor S2 near both ends of the blade 81 in the main scanning direction, it is possible to detect the frictional force imbalance at both ends of the blade 81 in the main scanning direction.

[Cleaning blade friction force change means]
For the frictional force changing means 8B, toner band formation or lubricant application on the image carrier 1 or temperature control of the contact portion (edge portion) of the blade 81 with the image carrier 1 is used. Changing the setting conditions (change in contact force, etc.) of the blade 81 to the image carrier 1 is not preferable because the cleaning property also changes. The frictional force changing means 8B changes substantially continuously in the main scanning direction. If there is a large step or breaks, the frictional force imbalance of the blade 81 in the main scanning direction cannot be corrected stably.

  The frictional force of the blade 81 can be generally changed by means such as toner band formation or lubricant application on the image carrier 1 or temperature control of the blade 81. The frictional force in the main scanning direction of the blade 81 can be changed by operating the frictional force changing means 8B that is asymmetric in the main scanning direction. Specifically, for example, in the case of a toner band, a toner band in which the band width sequentially changes in two or more main scanning directions selected according to the direction of frictional force imbalance, or in the case of lubricant application, the main scanning direction. There are two coating mechanisms that change the coating amount sequentially, and each direction is staggered in the main scanning direction, and either one of the coating mechanisms is selected according to the direction of frictional force imbalance, If necessary, it is sufficient to have a cooling means or a heating means that reduces the frictional force imbalance in the main scanning direction. If it is a heating means, the exhaust heat from the fixing device 9 can be used.

[Cleaning blade frictional force comparison means]
The output from the frictional force detecting means 8A is input to the frictional force comparing means 8C to the CPU that controls the image forming apparatus A and compared by arithmetic processing (software). When using a level changing means described later, it is necessary to detect which level of frictional force imbalance at both ends of the blade 81 is detected. With software, leveling can be easily performed.

  FIG. 3 is a block diagram showing the frictional force control of the blade 81 according to the present invention.

  The frictional force changing means 8B is provided with an asymmetric level changing means 8D that can change the level of the frictional force changing, and the frictional force comparing means 8C is a frictional force imbalance level detecting means 8E that can detect the frictional force imbalance level. The asymmetric level changing means 8D is controlled by the unbalance level detected by the frictional force imbalance level detecting means 8E.

  The frictional force imbalance of the blade 81 can be corrected more stably without the frictional force changing means 8B acting excessively or insufficiently. The asymmetric level changing means 8D changes, for example, the sub-scanning direction width of the toner band that is asymmetric in the main scanning direction, or changes the amount of lubricant applied by changing the pressing force of the lubricant asymmetrically in the main scanning direction. The conditions of the means for cooling or heating the vicinity of the blade 81 asymmetrically in the main scanning direction (for example, the air volume at the exhaust port described later) are changed.

[Image forming apparatus]
Image formation method: electrophotography (Carlson process) dry two-component magnetic brush reversal development method,
Image carrier 1: negatively charged OPC drum (film thickness 30 μm), φ80 mm, rotation linear velocity 280 mm / sec, charging potential −750 V, photosensitive layer main scanning direction length 350 mm,
Charging means 2: scorotron, charging current value of −800 μA, grid voltage of −730 V,
Image exposure apparatus 3: laser scanning method, wavelength 780 nm, 600 dpi, laser power 300 μW, beam diameter main scanning direction 60 μm, sub-scanning direction 80 μm, incident angle to OPC 10 °, PWM 256 exposure level, scanning width 310 mm,
Developer: carrier particle size 60 μm, toner particle size 6.5 μm (non-magnetic, manufactured by emulsion polymerization method), toner concentration 5%, shape factor SF-1 120, shape factor SF-2 110,
SF-1 indicates the degree of spherical shape, and SF-2 indicates the degree of unevenness. It is given by the following formula.

SF-1 = (Lmax ² / A) × (π / 4) × 100
SF-2 = (round ² / A) × (1 / 4π) × 100
Lmax; Maximum diameter Round; Perimeter A; Toner projection area Developing device 4: Bias -600V, sleeve diameter φ40mm, rotational linear velocity 560mm / sec, developing magnetic angle + 6 °, transfer residual toner removed by cleaning to developer Toner recycling system to return, Peak magnetic flux density of developing magnet vertical magnetic field 100mT, OPC surface to developing sleeve surface distance 0.50mm, developer transport amount 900g / m ²
Toner density control: Detect the toner density using a magnetic permeability sensor and control the amount of replenished toner. Transfer means 5, charge removal means 6: electrostatic transfer, electrostatic separation system Separation claw 7: auxiliary separation, solenoid drive Cleaning device 8: Fixed counter system, using urethane rubber blade (product name 234700, manufactured by Hokushin Kogyo), hardness 70 ° (JIS A hardness), Young's modulus 65 kg / cm ² , rebound resilience 68% (25 ° C), contact angle 20 with drum °, the amount of biting of the blade 81 into the image carrier 1 is 1 mm, the thickness is 2 mm, and the length in the main scanning direction is 340 mm.
Friction force control of the blade 81: The output value from the friction force detection means 8A is compared by the friction force comparison means 8C, and the CPU controls the friction force imbalance at the end of the blade 81 in the main scanning direction.

  Fixing device 9: a heat roller fixing method in which a heating roller using a halogen lamp as a heat source and a pressure roller are combined, and the heating roller surface temperature is controlled at 170 ° C.

[Cleaning blade]
When the frictional force between the blade 81 and the image carrier 1 is changed by changing the biting amount of the blade 81, that is, the contact force, a change in the vibration of the blade 81 and a heater in the image carrier 1 are provided. FIG. 4 shows the result of preliminary measurement of the change in the friction force when the temperature is changed by changing the friction force between the blade 81 and the image carrier 1 by raising the temperature of the blade 81. FIG. 4 is a characteristic diagram of the blade 81.

  The vibration is measured by using the vibration sensor “NP-3211 (manufactured by Ono Sokki Co., Ltd.)” to measure the average of the amplitude of all waveforms within 1 second. With only the body 1 set, the brushless DC drum motor torque was converted into torque using the current probe “AP015 (manufactured by LeCroy)” and the oscilloscope “LT344 (manufactured by LeCroy)”.

  FIG. 4A is a characteristic diagram showing the average vibration intensity (G) with respect to the amount of biting (mm) of the blade 81 into the image carrier 1. As illustrated, when the amount of biting of the blade 81 increases, the average vibration strength of the blade 81 increases.

  FIG. 4B is a characteristic diagram showing the torque (N · cm) of the blade 81 with respect to the temperature (° C.) of the blade 81. As illustrated, when the temperature of the blade 81 increases, the torque of the blade 81 increases.

  Thus, if the vibration and temperature of the blade 81 or the temperature in the vicinity thereof can be detected, the frictional force can be indirectly detected.

  The following examples were all performed in a high-temperature and high-humidity (30 ° C./80% RH) environment in which the blade 81 was easily turned up.

  Further, in order to appropriately accelerate the occurrence of turning of the blade 81, the embodiment was performed by the following two means.

  5A is a cross-sectional view of the blade 81 held by the blade support member 82, and FIGS. 5B and 5C are front views of the blade 81 held by the blade support member 82. FIG.

  [Acceleration 1] As shown in FIG. 5B, the free length L of the blade 81 held by the blade support member 82 was continuously changed slightly in the main scanning direction (from the left end to the right end in the figure). A blade 81 was used.

  Further, as shown in FIG. 5C, the blade 81 was used in which the free length L of the blade 81 was slightly changed continuously in the main scanning direction (9.5 mm → 9 mm from the left end portion to the right end portion in the drawing). .

  In the configuration of the blade 81 of the image forming apparatus A, generally, the longer the free length L, the larger the amount of biting, and thus the greater the frictional force.

  A sheet-passing test was conducted by continuous printing on A4 size paper P having a printing rate of 6% per sheet.

  [Acceleration 2] Although the free length L of the blade 81 is the same (9 mm) in the main scanning direction, printing on the image carrier 1 is performed only in the range from the center to one end of the image carrier 1 in the main scanning direction. (See FIG. 6A). In addition, printing was performed only in the range from the center of the image carrier 1 to the other end on the opposite side (see FIG. 6B).

  A sheet-passing test was conducted by continuous printing on A4-size paper P having a print printing rate of 3% per sheet.

  FIG. 6 is a front view showing the printing range on the image carrier 1 and the blade 81.

[Example 1]
FIG. 7 is a front view of the blade 81 to which the vibration sensor S1 is attached.

  Friction force detecting means 8A: The vibration sensor S1 was affixed to both ends of the rubber part in the main scanning direction of the blade 81.

  FIG. 8A is a perspective view of the image carrier 1 and the blade 81.

  Friction force changing means 8B: A belt-like toner image having an asymmetric width in the sub-scanning direction is formed in the non-image area of the image carrier 1 at a rate of once per 10 prints. The belt-like toner image is effective not only in turning over but also in stabilizing the friction force in the main scanning direction of the edge portion where the blade 81 abuts the image carrier 1 and preventing abnormal vibrations. In this case, a belt-like toner image symmetrical in the main scanning direction (width in the sub-scanning direction 0.5 mm) was created at the same rate.

  FIG. 9A is a diagram showing the band width (two steps) of the belt-like toner image and the average vibration intensity difference between both ends of the blade 81 in the frictional force changing means 8B.

  According to FIG. 9A, the band width of the belt-like toner image is changed by the output from the frictional force detecting means 8A.

  The friction force comparison means 8C is provided with the friction force imbalance level detection means 8E, and the friction force change means 8B is provided with the asymmetric level change means 8D.

  Asymmetric level changing means: According to the table of FIG. 9B, the asymmetric belt-like toner image selected by the frictional force imbalance level detecting means 8E in the frictional force comparing means 8C inputted with the output from the frictional force detecting means 8A. The band width of was changed.

  FIG. 9B shows the band width (four steps) of the belt-like toner image and the average vibration intensity difference between both ends of the blade 81 in the asymmetric level changing means 8C.

  As a reference, it is confirmed that there is no frictional force changing means 8B and a conventional case where a belt-like toner image (band width in the sub-scanning direction 0.5 mm) that is always symmetrical in the main scanning direction is created at a rate of once every 10 sheets is printed. did.

[In the case of the present invention]
Regardless of the presence or absence of the asymmetric level changing means 8D, the blade 81 was not turned up after printing 10,000 sheets in the [Acceleration 1] and [Acceleration 2] tests.

  The average vibration intensity difference monitored was 0.25 G or less without the asymmetric level changing means 8D, and 0.2 G or less with the asymmetric level changing means 8D.

[Conventional case]
[Acceleration 1] In the test, the blade 81 was turned from the long side of the free length L after printing 3000 sheets. The average vibration intensity difference just before turning over was about 0.31 G.

  [Acceleration 2] In the test, the blade 81 turned up from the non-printing area side after printing 6000 sheets. The average vibration intensity difference just before turning over was about 0.34G.

  In the conventional case, the same test was performed for the blade 81 with the long end of the free length L in the [acceleration 1] test as the opposite end, but this was also performed with 3300 prints and [acceleration 2] test. The printing area was set to the opposite end side in the main scanning direction in the same way, but this also caused the blade 81 to be turned over from the long free length L side or the non-printing area side when printing 6400 sheets. The average vibration intensity difference at the time was about 0.33 G and 0.35 G, respectively.

  In the case of the present invention, the test was performed in the same manner. In the [acceleration 1] and [acceleration 2] tests, there was no occurrence of turning of the blade 81 when printing 10,000 sheets, and the average vibration intensity difference was 0. 25G or less, and 0.2G or less with the asymmetric level changing means 8D.

[Example 2]
FIGS. 8B and 8C are front views of a width-asymmetric lubricant formed on the image carrier 1.

(A) Friction force detecting means 8A: same as in the first embodiment (B) Friction force changing means 8B: The width of the sub-scanning direction is asymmetrical across the entire width of the blade 81 in the main scanning direction, and the asymmetric directions are opposite to each other The two lubricants (metal soaps) 88A and 88B are selected in the friction force comparison means 8C to which the output from the friction force detection means 8A is input, and one of them is pressed against the brush-shaped application member 88C. Then, the brush is pressed against the image carrier 1.

  FIG. 10 is a side view of the width asymmetric lubricant applying means 88. There are various methods for selecting the lubricant to be pressed. For example, there is a combination of a stepping motor M1, a pinion gear G1, and a rack gear G2.

  FIG. 11 is a front view of the width asymmetric lubricant applying means 88.

  Table 1 shows the lubricant application control with respect to the average vibration intensity difference (G) at both ends of the blade 81 in the frictional force changing means 8B.

  Since the lubricant also has the effect of reducing the adhesion force of the toner to the image carrier 1, the sub-scan in the main scanning direction is different from the asymmetric level changing means 8D so that a constant amount is always applied to the image carrier 1. Lubricant 88D whose direction width is symmetrical is pressed against application member 88C. According to the above Table 1, the lubricant application was changed by the output from the frictional force detecting means 8A.

Lubricant supply member: zinc stearate (ZnSt), pencil hardness F to HB equivalent (product name Zinc stearate (manufactured by NOF Corporation)), main scanning direction length 340 mm, sub-scanning direction width 2 to 6 mm (main Two lubricant supply members 88A and 88B (see FIG. 11) continuously changing from one end to the other in the scanning direction), one lubricant supply member 88D having a constant width of 2 mm, and a pressing force of 2.9 N / m
Application member (brush) 88C: outer diameter φ16 mm, main scanning direction length 340 mm, hair length 4.5 mm, fiber diameter 6.25 d, fiber density 100,000 pieces / inch ² (1 inch is 25.4 mm) (Product name) SA-7 (manufactured by Toray)), the amount of biting into the image carrier 1 is 1 mm, the image carrier 1 is rotated in reverse, the rotational linear velocity ratio with respect to the image carrier 1 is −0.5,
The friction force comparison means 8C is provided with the friction force imbalance level detection means 8E, and the friction force change means 8B is provided with the asymmetric level change means 8D.

  Asymmetric level changing means 8D: A mechanism for changing the pressing force of the selected and pressed width asymmetric lubricant in the main scanning direction and comparing the frictional force inputted with the output from the frictional force detecting means 8A according to the table of Table 2. The pressing force is selected by the frictional force imbalance level detecting means 8E in the means 8C.

  Table 2 shows the lubricant pressing control with respect to the average vibration intensity difference (G) at both ends of the blade 81 in the asymmetric level changing means 8D.

  In Table 2, it is expressed as a pressing force when the pressing force without the asymmetric level changing means 8D is 100%.

  FIG. 12A is a front view of the frictional force changing means 8B in the main scanning direction. FIG. 12B is a front view of the oscillated friction force changing means 8B.

  The pressing force in the main scanning direction was changed using a mechanism that swings the entire mechanism holding the width asymmetric lubricant by a combination of a pinion gear G3 driven by a stepping motor M2 and a rack gear G4.

  The rack gear G4 is rotated by the rotation of the pinion gear G3, and the frame body 89 integral with the rack gear G4 swings about the rotation shaft 88E.

  As a reference, the conventional case in which only the lubricant 88D having a symmetrical (2 mm) width in the sub-scanning direction is pressed against the application member 88C without the frictional force changing means 8B was also confirmed.

[In the case of the present invention]
Regardless of the presence or absence of the asymmetric level changing means 8D, in the [Acceleration 1] and [Acceleration 2] tests, the blade 81 was not turned up after printing 10,000 sheets.

  The average vibration intensity difference monitored was 0.25 G or less without the asymmetric level changing means 8D, and 0.2 G or less with the asymmetric level changing means 8D.

[Conventional case]
[Acceleration No. 1] In the test, the blade 81 was turned up from the longer free length side after printing 3200 sheets. The average vibration intensity difference just before turning over was about 0.34G.

  [Acceleration 2] In the test, the blade 81 turned over from the non-printing area side after printing 6300 sheets. The average vibration intensity difference just before turning over was about 0.36G.

  In the conventional case, the same test was performed for the blade 81 with the long side of the free length L in the [acceleration 1] test as the opposite end, but this was also performed with 3200 prints and [acceleration 2] test. The printing area was set to the end side opposite to the main scanning direction in the same manner, but this also caused the blade 81 to turn over from the long side of the free length or the non-printing area side when printing 6000 sheets. The difference in average vibration intensity was about 0.32G and 0.34G, respectively.

  In the case of the present invention, the test was performed in the same manner. However, in the [acceleration 1] and [acceleration 2] tests, the blade 81 was not turned up after printing 10,000 sheets, and the average vibration intensity difference was 0.25 G without the asymmetric level changing means 8D. Hereinafter, it was 0.2 G or less with the asymmetric level changing means 8D.

[Example 3]
Friction force detecting means 8A: same as in the first embodiment Friction force changing means 8B: A blowing device 90 for taking in outside air from the outside of the image forming apparatus A is installed in the cleaning device 8.

  FIG. 13 is a cross-sectional view of the blower 90. Fig.14 (a) is a front view which shows the X direction arrow of the air blower 90 shown in FIG. 14, and shows the exhaust port of an equilibrium state. FIG. 14B and FIG. 14C are front views showing asymmetric exhaust ports. FIG. 14D is an explanatory diagram of the exhaust rate of the asymmetric exhaust port.

  The air blower 90 can open and close the duct 91 serving as the air passage, the fan 92 provided at one air blow end of the duct 91, and the air outlet 93 and air outlet 93 of the other air blow end of the duct 91 in the vicinity of the blade 81. A shutter 94 is provided.

  The exhaust port 93 of the duct 91 is divided into ten locations, and the blade 81 is asymmetrically cooled in the main scanning direction by controlling a shutter 94 that can apply the outside air taken in with an asymmetrical air volume in the main scanning direction of the blade 81. I do. The movement control of the shutter 94 is performed by a stepping motor M3 that drives a pinion gear G5 that meshes with a rack gear G6 connected to both ends of the shutter 94.

The duct 93 has a duct sub-scanning direction width of about 10 mm, a main scanning direction width of 340 mm, and a DC axial fan (maximum air volume 1.3 m ³ / min., Maximum static pressure 49 Pa, rotation speed 3400 rpm).

  The air volume is theoretically the product of the wind speed and the cross-sectional area of the exhaust port, so it should not change even if a part of the partitioned exhaust port is blocked, but the pressure loss of the blocked exhaust port actually increases. An exhaust port that is blocked by the occurrence of turbulence in the event tends to increase the wind resistance and flow to the lower resistance exhaust port. The air velocity in the vicinity of each partitioned [asymmetric 1] exhaust port 93 in FIG. 14 was measured to determine the cross-sectional area of each partitioned exhaust port 93 and the multiplied air volume. The following results were obtained for the equilibrium state. . That is, the air volume difference can be set at both ends in the main scanning direction. [Asymmetric 2] had the same result although the direction was opposite.

  Therefore, with such a shutter structure, the cooling of the blade 81 can be asymmetrical in the main scanning direction, and the frictional forces at both ends can be balanced. According to Table 3 below, the cooling air volume in the main scanning direction of the blade 81 is changed by the output from the frictional force detecting means 8A.

  Table 3 shows the average vibration strength (two steps) at both ends of the blade 81 in the frictional force changing means 8B and the cooling air volume control at the side ends.

  The friction force comparison means 8C is provided with the friction force imbalance level detection means 8E, and the friction force change means 8B is provided with the asymmetric level change means 8D.

  Asymmetry level changing means 8D: By changing the angle of the shutter 94, the exhaust ports 93 of the ten ducts 91 are changed, and the asymmetric level of the cooling air volume of the blade 81 can be changed.

  The main scanning of the blade 81 selected by the frictional force imbalance level detection means 8E in the frictional force comparison means 8C to which the output from the frictional force detection means 8A is input according to the shutter angle and the air volume measured in advance in Table 4 below. Change the directional cooling airflow.

  Table 4 shows the average vibration intensity (four steps) at both ends of the blade 81 in the asymmetric level changing means 8D and the cooling air volume control at the side ends.

  As a reference, the conventional case where the blade 81 is cooled evenly symmetrically in the main scanning direction without the frictional force changing means 8B was also confirmed.

[In the case of the present invention]
Regardless of the presence or absence of the asymmetrical level changing means 8D, the blade 81 was not turned up after printing 10,000 sheets in both [Acceleration 1] and [Acceleration 2] tests.

  The average vibration intensity difference monitored was 0.25 G or less without the asymmetric level changing means 8D, and 0.2 G or less with the asymmetric level changing means 8D.

[Conventional case]
[Acceleration 1] In the test, the blade 81 was turned up from the long free side after printing 3000 sheets. The average vibration intensity difference immediately before turning is about 0.35 G.

  [Acceleration 2] In the test, the blade 81 turned over from the non-printing area side after printing 5800 sheets. The average vibration intensity difference just before turning is about 0.33G.

  In the conventional case, the same test was performed with the blade 81 having the long side of the free length L as the opposite end in the [Acceleration 1] test, but this was also performed with 2900 prints and [Acceleration 2] test. The printing area was set to the end opposite to the main scanning direction in the same manner, but this also caused the turning of the blade 81 from the long side of the free length L or the non-printing area side when printing 6100 sheets. The average vibration intensity difference at that time was about 0.36 G and 0.35 G, respectively.

  In the case of the present invention, the test was performed in the same manner, but in the [acceleration 1] and [acceleration 2] tests, there was no occurrence of turning of the blade 81 after printing 10,000 sheets, and the average vibration intensity difference was 0.25 G without the asymmetric level changing means 8D. Hereinafter, it was 0.2 G or less with the asymmetric level changing means 8D.

[Example 4]
Friction force detecting means 8A: Same as in the first embodiment Friction force changing means 8B: The structure is the same as that in the third embodiment (see FIGS. 13 and 14), but the atmosphere taken in by the fan 92 is not the outside air but the fixing device 9 It has a shutter 94 that can capture an ambient atmosphere having a high temperature and can apply the ambient atmosphere of the fixing device 9 captured with an asymmetric air volume in the main scanning direction of the blade 81, and the blade 81 is controlled by controlling the shutter 94. Heating is performed asymmetrically in the main scanning direction. In this embodiment, the air temperature at the exhaust port 93 was about 60 ° C. By increasing the temperature on the side where vibration is small, the frictional force is increased and the frictional force at both ends in the main scanning direction is balanced. Further, since the temperature of the blade 81 does not need to be raised when the frictional forces at both ends are balanced, the exhaust port 93 is closed by the shutter 94 and the fan 92 is stopped.

  Table 5 shows the average vibration intensity difference (two steps) at both ends of the blade 81 in the frictional force changing means 8B and the heating air volume at the side ends.

  According to Table 5, the amount of heating air in the main scanning direction of the blade 81 is changed by the output from the frictional force detecting means 8A.

  The friction force comparison means 8C is provided with the friction force imbalance level detection means 8E, and the friction force change means 8B is provided with the asymmetric level change means 8D.

  Asymmetry level changing means 8D: By changing the angle of the shutter 94, the exhaust ports 93 of ten ducts are changed, and the asymmetric level of the heating air volume of the blade 81 can be changed.

  The friction force imbalance level detection means 8E in the friction force comparison means 8C inputted with the output from the friction force detection means 8A in the following Table 6 is selected by the friction force imbalance level detection means 8E according to the angle and air volume of the shutter 94 measured in advance. Change the main scanning direction heating air volume.

  Table 6 shows the average vibration intensity (4 stages) at both ends of the blade 81 in the asymmetric level changing means 8D and the control of the heating air volume at both ends.

  As a reference, a conventional case in which the blade 81 is simply cooled symmetrically in the main scanning direction without the frictional force asymmetry changing means was also confirmed.

[In the case of the present invention]
Regardless of the presence / absence of the asymmetric level changing means 8D, the blade 81 is not turned over when printing 10,000 sheets in both [Acceleration 1] and [Acceleration 2] tests.

  The average vibration intensity difference monitored was 0.25 G or less without the asymmetric level changing means 8D, and 0.2 G or less with the asymmetric level changing means 8D.

[Conventional case]
[Acceleration 1] In the test, the blade 81 turned over from the long free length L side after printing 3300 sheets. The average vibration intensity difference just before turning over was about 0.31 G.

  [Acceleration 2] In the test, the blade 81 turned over from the non-printing area side after printing 6200 sheets. The average vibration intensity difference just before turning is about 0.32G.

  In the conventional case, the same test was performed for the blade 81 with the end of the longer free length in the [Acceleration 1] test, but this was also done with 3100 prints and in the [Acceleration 2] test. The printing area is the same as the end on the opposite side of the main scanning direction, but this is also the case when 5700 sheets are printed and the blade 81 is turned over from the long free length L side or the non-printing area side. The difference in average vibration intensity was about 0.33 G and 0.33 G, respectively.

  In the case of the present invention, the test was performed in the same manner, but in the [acceleration 1] and [acceleration 2] tests, there was no occurrence of turning of the blade 81 after printing 10,000 sheets, and the average vibration intensity difference was 0.25 G without the asymmetric level changing means 8D. Hereinafter, it was 0.2 G or less with the asymmetric level changing means 8D.

[Example 5]
Friction force detecting means 8A: A temperature sensor (thermocouple) S2 was affixed to the extreme ends of the rubber part in the main scanning direction of the blade 81.

  FIG. 15 is a front view of the blade 81 to which the temperature sensor S2 that is the frictional force detecting means 8A is attached.

  Friction force changing means 8B: same as in the first embodiment. However, the following FIG. 16A was used.

  FIG. 16A is a diagram showing the band width of the belt-like toner image in the frictional force changing means 8B and the temperature difference (two steps) at both ends of the blade 81. FIG.

  The friction force comparison means 8C is provided with the friction force imbalance level detection means 8E, and the friction force change means 8B is provided with the asymmetric level change means 8D.

  Asymmetric level changing means 8D: according to FIG. 16B below, the asymmetric belt-like toner selected by the frictional force imbalance level detecting means 8E in the frictional force comparing means 8C inputted with the output from the frictional force detecting means 8A. Changed the width of the image.

  FIG. 16B shows the band width of the belt-like toner image in the asymmetric level changing means 8D and the temperature difference (four steps) at both ends of the blade 81.

  As a reference, the conventional case in which the frictional force changing means 8B is not provided and a belt-like toner image (width in the sub-scanning direction 0.5 mm) that is always symmetrical in the main scanning direction at a rate of once every 10 sheets is confirmed. .

[In the case of the present invention]
Regardless of the presence or absence of the asymmetric level changing means 8D, in the [Acceleration 1] and [Acceleration 2] tests, the blade 81 was not turned up after printing 10,000 sheets.

  The temperature difference between both ends monitored was 4 ° C. or less without the asymmetric level changing means 8D, and 3.5 ° C. or less with the asymmetric level changing means 8D.

[Conventional case]
[Acceleration 1] In the test, the blade 81 was turned from the long side of the free length L after printing 3000 sheets. The temperature difference at both ends just before turning over was about 4.7 ° C.

  [Acceleration 2] In the test, the blade 81 turned up from the non-printing area side after printing 6000 sheets. The temperature difference at both ends just before turning over was about 5.1 ° C.

  In the conventional case, the same test was performed for the blade 81 with the long end of the free length L in the [acceleration 1] test as the opposite end, but this was also performed with 3300 prints and [acceleration 2] test. The printing area was set to the end opposite to the main scanning direction in the same manner, but this also caused the blade 81 to be turned over from the longer free length L side or the non-printing area side when printing 5900 sheets. The temperature difference at both ends was about 4.7 ° C. and 4.8 ° C., respectively.

  In the case of the present invention, the test was performed in the same manner, but in the [acceleration 1] and [acceleration 2] tests, there was no occurrence of turning of the blade 81 after printing 10,000 sheets, and the temperature difference between both ends was 4 ° C. or less without the asymmetric level changing means 8D. The temperature was 3.5 ° C. or less with the asymmetric level changing means 8D.

[Example 6]
Friction force detecting means 8A: same as in the fifth embodiment Friction force changing means 8B: same as in the second embodiment. However, Table 7 below was used.

  Table 7 shows the temperature difference (° C.) at both ends of the blade 81 in the frictional force changing means 8B and the lubricant supply control.

  The friction force comparison means 8C is provided with the friction force imbalance level detection means 8E, and the friction force change means 8B is provided with the asymmetric level change means 8D.

  Asymmetric level changing means 8D: The configuration is the same as that of the second embodiment, and the pressing force is changed according to Table 8 below.

  Table 8 shows the temperature difference (° C.) at both ends of the blade 81 in the asymmetric level changing means 8D and the pressing force control.

  As a reference, a conventional case was also confirmed in which the friction force changing means 8B was not provided and only the lubricant 88D having a symmetrical width (2 mm) in the sub-scanning direction was pressed against the application member (brush) 88C.

[In the case of the present invention]
Regardless of the presence or absence of the asymmetric level changing means 8D, the blade 81 was not turned up after printing 10,000 sheets in the [Acceleration 1] and [Acceleration 2] tests.

  The temperature difference between both ends monitored was 4 ° C. or less without the asymmetric level changing means 8D, and 3.5 ° C. or less with the asymmetric level changing means 8D.

[Conventional case]
[Acceleration 1] In the test, the blade 81 was turned over from the long free length L side after printing 3500 sheets. The temperature difference at both ends immediately before turning was about 4.8 ° C.

  [Acceleration 2] In the test, the blade 81 turned over from the non-printing area side after printing 5700 sheets. The temperature difference at both ends just before turning over was about 4.7 ° C.

  In the conventional case, the same test was performed for the blade 81 with the long end of the free length L on the opposite side in the [Acceleration 1] test, but this was also performed with 3000 prints and [Acceleration 2] test. The printing area was set to the opposite end side in the main scanning direction in the same manner, but this also caused the blade 81 to turn over from the long free length L side or the non-printing area side when printing 6000 sheets. The temperature difference at both ends was about 5.0 ° C. and 4.7 ° C., respectively.

  In the case of the present invention, the test was performed in the same manner, but in the [acceleration 1] and [acceleration 2] tests, there was no occurrence of turning of the blade 81 after printing 10,000 sheets, and the temperature difference between both ends was 4 ° C. or less without the asymmetric level changing means 8D. The temperature was 3.5 ° C. or less with the asymmetric level changing means 8D.

[Example 7]
Friction force detecting means 8A: same as in the fifth embodiment Friction force changing means 8B: same as in the third embodiment. However, Table 9 below was used.

  Table 9 shows the control of the temperature difference (° C.) at both ends of the blade 81 and the air volume at the side ends in the frictional force changing means 8B.

  The friction force comparison means 8C is provided with the friction force imbalance level detection means 8E, and the friction force change means 8B is provided with the asymmetric level change means 8D.

  Asymmetric level changing means 8D: The configuration is the same as that of the third embodiment, and the amount of cooling air in the main scanning direction of the blade 81 is changed according to Table 10 below.

  Table 10 shows the temperature difference (° C.) at both ends of the blade 81 in the asymmetric level changing means 8D and the air flow force control at the side ends.

  As a reference, the conventional case where the blade 81 is cooled evenly symmetrically in the main scanning direction without the frictional force changing means 8B was also confirmed.

[In the case of the present invention]
Regardless of the presence or absence of the asymmetrical level changing means 8D, the blade 81 was not turned up after printing 10,000 sheets in both [Acceleration 1] and [Acceleration 2] tests.

  The temperature difference between both ends monitored was 4 ° C. or less without the asymmetric level changing means 8D, and 3.5 ° C. or less with the asymmetric level changing means 8D.

[Conventional case]
[Acceleration 1] In the test, the blade 81 turned over from the long free length L side after printing 3100 sheets. The temperature difference at both ends just before turning over was about 4.7 ° C.

  [Acceleration 2] In the test, the blade 81 turned over from the non-printing area side after printing 5900 sheets. The temperature difference at both ends immediately before turning was about 4.8 ° C.

  In the conventional case, the same test was performed for the blade 81 with the long end of the free length L in the [acceleration 1] test as the opposite end. The printing area was set to the end opposite to the main scanning direction in the same manner, but this also caused the blade 81 to turn over from the long side of the free length L or the non-printing area side when printing 6100 sheets. The temperature difference at both ends was about 4.9 ° C. and 4.8 ° C., respectively.

  In the case of the present invention, the test was performed in the same manner, but in the [acceleration 1] and [acceleration 2] tests, there was no occurrence of turning of the blade 81 after printing 10,000 sheets, and the temperature difference between both ends was 4 ° C. or less without the asymmetric level changing means 8D. The temperature was 3.5 ° C. or less with the asymmetric level changing means 8D.

[Example 8]
Friction force detecting means 8A: the same as that of the fifth embodiment Friction force changing means 8B: the same as that of the fourth embodiment. However, Table 11 below was used.

  Table 11 shows the control of the temperature difference (° C.) at both ends of the blade 81 and the air volume at the side ends in the frictional force changing means 8B.

  Asymmetric level changing means 8D: The configuration is the same as that of the fourth embodiment, and the amount of heating air in the main scanning direction of the blade 81 is changed according to Table 12 below.

  Table 12 shows the control of the temperature difference (° C.) at both ends of the blade 81 and the air volume at the side ends in the asymmetric level changing means 8D.

  As a reference, it was also confirmed that the blade 81 is simply cooled symmetrically in the main scanning direction without the frictional force changing means 8B.

[In the case of the present invention]
Regardless of the presence or absence of the asymmetrical level changing means 8D, the blade 81 was not turned up after printing 10,000 sheets in both [Acceleration 1] and [Acceleration 2] tests.

  The temperature difference between both ends monitored was 4 ° C. or less without the asymmetric level changing means 8D, and 3.5 ° C. or less with the asymmetric level changing means 8D.

[Conventional case]
[Acceleration 1] In the test, the blade 81 turned over from the long free length L side after printing 3000 sheets. The temperature difference at both ends just before turning over was about 5.1 ° C.

  [Acceleration 2] In the test, the blade 81 turned over from the non-printing area side after printing 6100 sheets. The temperature difference at both ends immediately before turning was about 4.8 ° C.

  In the conventional case, the same test was performed with the blade 81 having the long side of the free length L as the opposite end in the [Acceleration 1] test, but this was also performed with 2900 prints and [Acceleration 2] test. The printing area was set to the end side opposite to the main scanning direction in the same way, but this also caused the blade 81 to be turned over from the longer free length side or the non-printing area side when printing 5800 sheets. The temperature difference between both ends was about 4.7 ° C. and 4.7 ° C., respectively.

  In the case of the present invention, the test was performed in the same manner. However, in the [Acceleration 1] and [Acceleration 2] tests, there was no occurrence of turning of the blade 81 after printing 10,000 sheets, and the temperature difference between both ends was 4 ° C. or less without the asymmetric level changing means 8D The temperature was 3.5 ° C. or less with the asymmetric level changing means 8D.

  In Examples 5 to 8, thermocouples were attached to both ends of the blade 81 to monitor the temperature. However, the temperature may be monitored by installing the thermocouple near both ends of the blade 81, or both ends of the blade 81 may be monitored. Any position can be used as long as the temperature change can be detected even if it is installed in the vicinity of the image carrier 1 in the vicinity of the image forming unit or brought into contact with the image carrier 1.

  Further, although the accuracy of correcting the frictional force imbalance is slightly rough, it can be said that it is effective to use the frictional force changing means 8B in a binary manner without providing the asymmetric level changing means.

  From the results of these embodiments, the frictional force at both ends in the main scanning direction of the blade 81 is detected, and the frictional force changing means 8B that is asymmetrical in the main scanning direction is operated when the frictional force is unbalanced at both ends. By changing the frictional force on one of the ends and controlling the frictional forces on both ends to be substantially the same, it is possible to effectively prevent the blade 81 from turning over.

[Color image forming apparatus]
FIG. 17 is a configuration diagram of a color image forming apparatus according to the present invention. In addition, about the code | symbol used in drawing, the same code | symbol is attached | subjected to the part which has the same function as FIG. Further, differences from FIG. 1 will be described.

  The image forming apparatus main body A is called a tandem color image forming apparatus, and is composed of a plurality of sets of image forming means AY, AM, AC, AK, a transfer material feeding / conveying means, and a fixing device 9.

  The image forming unit AY that forms a yellow (Y) image includes a charging unit 2Y, an image exposing unit 3Y, a developing unit 4Y, and a cleaning unit 8Y disposed around the image carrier 1Y. The image forming unit AM that forms a magenta (M) color image includes an image carrier 1M, a charging unit 2M, an image exposure unit 3M, a developing device 4M, and a cleaning device 8M. An image forming unit AC that forms a cyan (C) color image includes an image carrier 1C, a charging unit 2C, an image exposing unit 3C, a developing device 4C, and a cleaning device 8CN. The image forming unit AK that forms a black (K) image includes an image carrier 1K, a charging unit 2K, an image exposure unit 3K, a developing device 4K, and a cleaning device 8K.

  The charging unit 2Y and the image exposing unit 3Y, the charging unit 2M and the image exposing unit 3M, the charging unit 2C and the image exposing unit 3C, and the charging unit 2K and the image exposing unit 3K constitute a latent image forming unit.

  4Y, 4M, 4C, and 4K are developing devices that contain a two-component developer composed of a small particle size toner of yellow (Y), magenta (M), cyan (C), and black (K) and a carrier.

  The intermediate transfer member 5B is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming means AY, AM, AC, AK is sequentially transferred onto the rotating intermediate transfer body 5B by the primary transfer means 5Y, 5M, 5C, 5K, and a combined color image is obtained. It is formed.

  The paper P accommodated in the paper feeding cassette 10 of the transfer material paper feeding / conveying means is fed by the first paper feeding means 11, passed through the second paper feeding unit 12, and transported to the secondary transfer means 5 </ b> A. After the color image is transferred onto the paper P, the paper P on which the color image is transferred is sandwiched by the fixing device 9 and the toner image on the paper P is fixed by applying heat and pressure to the paper P. The sheet is fixed on P, pinched by the sheet discharge means 14, and discharged outside the apparatus.

  On the other hand, after the color image is transferred to the transfer material P by the secondary transfer means 5A, the residual toner is removed by the cleaning device 8X from the intermediate transfer body 5B from which the paper P is separated by curvature.

  The cleaning devices 8X, 8Y, 8M, 8CN, and 8K include frictional force detection means 8A that detects a frictional force at both ends of the outer peripheral surface of the intermediate transfer member 5B and both ends where the blade 81 is in sliding contact, and an intermediate transfer member. 5B and a frictional force changing means 8B for changing the frictional force between the blade 81 and the frictional force detecting means 8A detecting that the frictional forces at both ends of the intermediate transfer body 5B and the blade 81 are unbalanced. Then, the frictional force changing means 8 </ b> B changes the frictional force on either one of both end portions of the blade 81 and controls the frictional force over the entire length of the blade 81 to be uniform.

1 is an overall configuration diagram of an image forming apparatus including an image forming apparatus main body, an image reading apparatus, and an automatic document feeder. Sectional drawing of a cleaning apparatus. The block diagram which shows the frictional force control of the braid | blade which concerns on this invention. The characteristic diagram of a blade. Sectional drawing and the front view of a braid | blade currently hold | maintained at the braid | blade support member. FIG. 3 is a front view showing a printing range and a blade on an image carrier. The front view of the braid | blade which stuck the vibration sensor. FIG. 3 is a perspective view of an image carrier and a blade, and a front view of a width-asymmetric lubricant formed on the image carrier. The figure which shows the belt width of a belt-shaped toner image, and the average vibration intensity difference of the both ends of a braid | blade. The side view of a width | variety asymmetrical lubrication application means, and the front view of a lubricant asymmetrical in a scanning direction. The front view of a width | variety asymmetrical lubrication application means. The front view of the frictional force change means in the main scanning direction. Sectional drawing of an air blower. The front view which shows the exhaust port of the equilibrium state of an air blower, the front view which shows an asymmetrical exhaust port, and explanatory drawing of the exhaust rate of an asymmetrical exhaust port. The front view of the braid | blade which attached the temperature sensor. The figure which shows the belt width of a belt-shaped toner image, and the temperature difference of the both ends of a braid | blade. 1 is a configuration diagram of a color image forming apparatus according to the present invention.

Explanation of symbols

8, 8X, 8Y, 8M, 8CN, 8K Cleaning device 8A Friction force detection means 8B Friction force change means 8C Friction force comparison means 8D Asymmetric level change means 8E Friction force imbalance level detection means 9 Fixing device 81 Cleaning blade (blade)
82 Blade support member 88 Width asymmetric lubricant application means 88A, 88B Width asymmetric lubricant 88C Application member (brush)
88D Lubricant with constant width 90 Blower 91 Duct 92 Fan 93 Exhaust port 94 Shutter A Image forming apparatus main body G1, G3, G5 Pinion gear G2, G4, G6 Rack gear M1, M2, M3 Stepping motor S1 Vibration sensor S2 Temperature sensor (thermocouple )

Claims (13)

In the image forming apparatus, after the electrostatic latent image formed on the image carrier is developed with toner in the developing device and transferred to a transfer material, the toner remaining on the image carrier is cleaned by a cleaning blade.
Friction force detection means for detecting a friction force at both ends of the outer peripheral surface of the image carrier and both ends where the cleaning blade is in sliding contact;
Frictional force changing means for changing the frictional force between the image carrier and the cleaning blade;
With
When the frictional force detecting means detects that the frictional force at each end of the image carrier and the cleaning blade is unbalanced, the frictional force over the entire length of the cleaning blade is uniform. An image forming apparatus, wherein the frictional force changing means controls the frictional force of each part of the cleaning blade to change. 2. The image forming apparatus according to claim 1, wherein the frictional force changing unit controls the frictional force on one of the two end portions of the cleaning blade to change. The frictional force detecting means is disposed in contact with or near the both end portions of the outer peripheral surface parallel to the rotation axis direction of the cleaning blade or the image carrier, and the cleaning blade and the image carrier. The image forming apparatus according to claim 1, wherein the image forming apparatus detects a frictional force between the two. 4. The image according to claim 1, wherein the frictional force detecting means is a vibration sensor disposed in the vicinity of both ends in the longitudinal direction parallel to the rotation axis direction of the image carrier of the cleaning blade. Forming equipment. 5. The temperature sensor disposed in the vicinity of both ends of the cleaning blade in the longitudinal direction parallel to the rotation axis direction of the image carrier. The image forming apparatus described in the item. The frictional force changing means is a means for forming a belt-like toner image by attaching toner to at least a part of the non-image forming portion on which the electrostatic latent image is not formed on the image carrier. The image forming apparatus according to claim 1. 2. The frictional force changing means is means for applying a lubricant to at least a part of a non-image forming portion on which the electrostatic latent image is not formed on the image carrier. Image forming apparatus. The image forming apparatus according to claim 1, wherein the frictional force changing unit is a temperature changing unit that changes a temperature of a contact portion between the cleaning blade and the image carrier. The frictional force changing unit controls the frictional force so as to continuously change in a longitudinal direction parallel to a rotation axis direction of the image carrier. Image forming apparatus. In the image forming apparatus, after the electrostatic latent image formed on the image carrier is developed with toner in the developing device and transferred to a transfer material, the toner remaining on the image carrier is cleaned by a cleaning blade.
Friction force detection means for detecting a friction force at both ends of the outer peripheral surface of the image carrier and both ends where the cleaning blade is in sliding contact;
Frictional force changing means for changing the frictional force between the image carrier and the cleaning blade;
Friction force comparison means for comparing the friction force between one end portion and the other end portion of the cleaning blade and the outer peripheral surface of the image carrier in the rotation axis direction based on a friction force detection signal from the friction force detection means. And
The image forming apparatus, wherein the frictional force comparing means compares the output from the frictional force detecting means with a control means. 11. The image forming apparatus according to claim 10, wherein the frictional force changing unit is operated by a signal from the frictional force comparing unit. The frictional force changing unit causes the toner from the developing device to adhere to at least a part of the non-image area where the electrostatic latent image is not formed on the image carrier by the frictional force detection signal from the frictional force detecting unit. The image forming apparatus according to claim 10. Image formation in which an electrostatic latent image formed on a rotating image carrier is developed with toner in a developing device and transferred to an intermediate transfer member, and then the toner remaining on the intermediate transfer member is cleaned with a cleaning blade In the device
Friction force detecting means for detecting a frictional force at both end portions where the periphery of the outer peripheral surface of the intermediate transfer body and the cleaning blade are in sliding contact with each other;
Friction force changing means for changing the friction force between the intermediate transfer member and the cleaning blade,
When the frictional force detecting means detects that the frictional force at both ends of the intermediate transfer member and the cleaning blade is unbalanced, the frictional force is uniform so that the frictional force over the entire length of the cleaning blade is uniform. An image forming apparatus, wherein the force changing means controls to change the frictional force of each part of the cleaning blade.

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