JP2005202026A - Cleaning apparatus, cleaning method, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To always demonstrate a good cleaning function by solving defects such as occurrence of cleaning failure, blade squeaking or chattering, blade curling up or filming in a cleaning apparatus. <P>SOLUTION: A friction force detection means 42, detecting the friction force of a cleaning blade 35 against a photoreceptor (image carrier) 10 is provided. The friction force detection means can be constituted from a pressure-sensitive element 40 attached to the cleaning blade and a detection circuit 41 detecting variation in its electrical property. Or the means can be constituted from conductive particles provided dispersed in the cleaning blade and a detection circuit detecting the variation in the electrical property of the cleaning blade. Or the means can be constituted by forming a detection circuit by resistive thin film on the cleaning blade. Or the means can be constituted from a distortion sensor attached to the cleaning blade and a detection circuit detecting the variation in the electrical property. Then, on receiving an output signal from the detection circuit, an appropriate control is carried out by a control circuit 43 based on the variation pattern. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, or a complex machine thereof. Among them, in particular, an electrophotographic method, an electrostatic recording method, an electrostatic printing method, etc., in which a toner image formed on an image carrier is directly or indirectly transferred and recorded on a recording medium such as a sheet / OHP film. The present invention relates to an image forming apparatus. In addition, in such an image forming apparatus, the present invention relates to a cleaning apparatus, a cleaning method, and a process cartridge for removing toner remaining on an image carrier after image transfer using a cleaning blade.

  Conventionally, in an electrophotographic image forming apparatus, the surface of a drum-like or belt-like image carrier is uniformly charged positively or negatively using a charging device, and optical writing is performed by an exposure device. After the electrostatic latent image is formed, the developing device attaches toner having a polarity opposite to that of the electrostatic latent image to make the image visible, and the transferred image is directly or via an intermediate transfer member using the transfer device. It was indirectly transferred to a recording medium such as a sheet / OHP film.

  Then, the recording medium after image transfer is placed in a fixing device, and for example, heat and pressure are applied to fix the transferred image. On the other hand, the image carrier and the intermediate transfer member after the image transfer are prepared for re-image formation by removing the toner remaining on the surface by using a cleaning device along with the rotation of the image carrier and the intermediate transfer member.

  The cleaning device is a cleaning blade type in which the cleaning blade is held by a cleaning holder and the tip is pressed against the image carrier, and the peripheral surface of a conductive or insulating fur brush roller contacts the surface of the image carrier and rotates. There are a fur brush roller method, a magnetic brush cleaning method in which magnetic powder is magnetized on the surface of the magnetic roller, and the like.

  Here, the fur brush roller method, the magnetic brush cleaning method, and the like have a problem in that the configuration and the like are complicated, and the apparatus becomes large and the cost increases. Therefore, an inexpensive cleaning blade method has been often used.

JP 2000-112187 A JP-A-6-9555 JP-A-9-258627

  However, in recent years, the toner particle size has been reduced in order to achieve high image quality such as 2400 dpi. From the viewpoint of energy saving, it is becoming mainstream to produce toner by a polymerization method. In the polymerization method, it is the cheapest to use the toner shape in a spherical state that does not require a deforming step. By making it spherical, the transfer efficiency can be improved, the amount of toner discarded as a transfer residual toner can be reduced, and the energy saving effect can be further improved.

  However, when the toner particle size is reduced, it becomes difficult to remove the toner by the amount of toner, and the cleaning ability is lowered. Further, when the toner is spheroidized, it becomes easy to pass through the cleaning blade, and defective cleaning tends to occur. For this reason, the hardness, material, thickness, free end length (projection amount from the cleaning holder), contact pressure, contact angle, and the like of the cleaning blade have been optimized in accordance with the linear velocity of the image carrier.

  However, due to poor cleaning due to toner slipping, blade squeaking and chatter occurring between the image carrier and the cleaning blade, blade turning up of the cleaning blade, toner additives, paper dust, etc. adhering to the surface of the image carrier There was a problem that caused problems such as filming.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to eliminate such problems in the cleaning device and always exhibit good cleaning performance.

  In order to achieve such an object, the first aspect of the present invention is to detect the frictional force of the cleaning blade against the image carrier in a cleaning device that removes toner remaining on the image carrier after image transfer using the cleaning blade. And a frictional force detecting means.

  The frictional force detecting means is composed of a pressure-sensitive element attached to the cleaning blade and a detection circuit for detecting a change in electrical characteristics thereof, or conductive particles provided dispersed in the cleaning blade, and a change in electrical characteristics of the cleaning blade. It is composed of a detection circuit that detects a change in the electrical characteristics of the cleaning blade, a strain sensor attached to the cleaning blade, and a detection circuit that detects a change in its electrical characteristics. Or

  Then, the cleaning blade is driven based on the output signal of the detection circuit to change the contact pressure of the cleaning blade to the image carrier, or the replacement time of the image carrier is determined based on the output signal of the detection circuit. Informing means for informing, or removing blade driving means for contacting and separating the filming removing blade from the image carrier based on the output signal of the detection circuit is provided.

  In order to achieve the above-mentioned object, a second aspect of the present invention is a cleaning method, wherein a constant image pattern is formed on an image carrier, and the image carrier at the constant image pattern forming position is formed. The frictional force of the cleaning blade is detected by the frictional force detection means, and control is performed based on the output signal of the frictional force detection means, and the toner remaining on the image carrier after image transfer is removed using the cleaning blade. It is characterized by that.

  Furthermore, in order to achieve the above-mentioned object, a third aspect of the present invention is a process cartridge, comprising the cleaning device according to any one of claims 1 to 8.

  Furthermore, in order to achieve the above-mentioned object, a fourth aspect of the present invention is an image forming apparatus, comprising the cleaning device according to any one of claims 1 to 8.

  Furthermore, in order to achieve the above object, a fifth aspect of the present invention is an image forming apparatus, comprising a plurality of process cartridges according to claim 10.

  According to the first aspect of the present invention, the frictional force of the cleaning blade against the image carrier is detected by the frictional force detection means, and the frictional force of the cleaning blade against the image carrier is optimized based on the output signal of the frictional force detection means. Therefore, there are poor cleaning due to toner slipping, blade noise and chatter generated between the image carrier and the cleaning blade, blade turning up of the cleaning blade, toner additives and paper dust on the surface of the image carrier. Problems such as the occurrence of filming due to adhesion can be solved, and a good cleaning performance can always be exhibited. Toner remaining on the image carrier after image transfer can be removed using a cleaning blade.

  According to the second aspect of the present invention, since the frictional force detecting means is composed of the pressure sensitive element attached to the cleaning blade and the detection circuit for detecting the change in the electric characteristic, the change in the electric characteristic of the pressure sensitive element is detected. By means of detection by a circuit and control based on the output signal, it is possible to eliminate the above-mentioned problems and always exhibit good cleaning performance by means that does not narrow the selection range of the material of the cleaning blade.

  According to the third aspect of the present invention, the frictional force detecting means is composed of conductive particles provided dispersed in the cleaning blade and a detection circuit for detecting a change in electrical characteristics of the cleaning blade. By means of detecting a change in electrical characteristics by a detection circuit and performing control based on the output signal to reduce the size of the cleaning blade, it is possible to solve the above-described problems and always exhibit good cleaning performance.

  According to the fourth aspect of the present invention, the frictional force detecting means is formed on the cleaning blade by forming a detection circuit with a resistive thin film. Control is performed based on the output signal, batch processing is possible, and mass production is good and inexpensive means can solve the above-described problems and always exhibit good cleaning performance.

  According to the fifth aspect of the present invention, the frictional force detecting means is composed of the strain sensor attached to the cleaning blade and the detection circuit for detecting the change in the electrical characteristics. Detection is performed and control is performed based on the output signal, and the above-described problems can be solved and inexpensive cleaning performance can always be exhibited by inexpensive means.

  According to the sixth aspect of the invention, since the cleaning blade is driven based on the output signal of the detection circuit to change the contact pressure of the cleaning blade against the image carrier, the output signal of the detection circuit is provided. Based on the above, the cleaning blade driving means is controlled to adjust the frictional force of the cleaning blade with respect to the image bearing member, so that the above-mentioned problems can be solved and always good cleaning performance can be exhibited. For example, when a cleaning failure occurs due to insufficient frictional force, the cleaning blade is driven by the cleaning blade driving means to increase the contact pressure. On the other hand, when excessive blade friction or blade turning occurs due to excessive frictional force, cleaning is performed by the cleaning blade driving means. Drive the blade to reduce the contact pressure.

  According to the seventh aspect of the present invention, since the notification means for notifying the replacement timing of the image carrier based on the output signal of the detection circuit is provided, the notification means notifies the image carrier based on the output signal of the detection circuit. It is possible to prompt replacement, and for example, it is possible to quickly eliminate a deterioration in cleaning performance due to filming.

  According to the eighth aspect of the invention, since the removal blade driving means for contacting and separating the filming removal blade with respect to the image carrier based on the output signal of the detection circuit is provided, the removal blade drive is performed based on the output signal of the detection circuit. By means of this, the filming removal blade can be brought into contact with and separated from the image carrier to effectively eliminate the occurrence of filming and always exhibit good cleaning performance.

  According to the ninth aspect of the present invention, a fixed image pattern is formed on the image carrier, and the frictional force of the cleaning blade against the image carrier at the fixed image pattern forming position is detected by the frictional force detecting means. Since the control is performed based on the output signal of the frictional force detecting means, it is possible to improve the detection accuracy by eliminating the variation due to the image pattern, and to exhibit better cleaning performance.

  According to a tenth aspect of the present invention, the process cartridge includes the cleaning device according to any one of the first to eighth aspects, so that miniaturization and maintainability are improved, and a good cleaning performance is always obtained. It is possible to provide a process cartridge provided with a cleaning device to be exhibited.

  According to the eleventh aspect of the present invention, since the image forming apparatus includes the cleaning apparatus according to any one of the first to eighth aspects, the image includes the cleaning apparatus that always exhibits good cleaning performance. A forming apparatus can be provided.

  According to the invention described in claim 12, since the image forming apparatus includes a plurality of process cartridges according to claim 10, the process cartridge is improved in size and maintenance, and always exhibits good cleaning performance. For example, a color image forming apparatus can be provided.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 shows an overall schematic configuration of an internal mechanism of an electrophotographic image forming apparatus according to the present invention.

  Reference numeral 100 in the figure denotes an image forming apparatus main body. The image forming apparatus main body 100 is placed on a sheet bank 200.

  The image forming apparatus main body 100 is provided with a drum-shaped photoconductor 10 as an image carrier. Around the photoconductor 10, in order from the roller-shaped charging device 11 arranged on the upper side in the figure, in the rotation direction (clockwise) of the photoconductor 10, the developing device 12 on the right side, the transfer device 13 on the lower side, and the left side In addition, a cleaning device 14 is disposed, and a neutralization device 15 is disposed on the upper left side.

  Among them, in the developing device 12, a polymerized toner manufactured by a polymerization method is used as the toner, and the polymerized toner is attached using a developing roller 16 to visualize the electrostatic latent image on the photoconductor 10. Reference numeral 17 denotes a toner supply device for supplying new toner to the developing device 12.

  Further, the transfer device 13 is configured by winding a transfer belt 20 between two left and right rollers 18 and 19 and pressing the transfer belt 20 against the peripheral surface of the photoconductor 10 at a transfer position. Reference numeral 21 denotes a belt cleaning device that removes toner and paper dust adhering to the transfer belt 20. Of course, the transfer device 13 is not limited to a belt shape as illustrated, but may be a roller shape or a non-contact transfer charger.

  In addition, the sheet (recording medium) S sent from the sheet bank 200 is transported inside the image forming apparatus main body 100, passes through the transfer position described above, and is discharged from the image forming apparatus main body 100 to the outside of the image forming apparatus main body 100. The sheet conveying path R for discharging is provided.

  In the sheet conveyance path R, a pair of registration rollers 22 and a pair of conveyance rollers 23 are provided upstream of the transfer position. Further, a fixing device 24 is provided downstream of the photoreceptor 10. The fixing device 24 includes a heating roller 25 that heats to a fixing temperature and a pressure roller 26 that presses the heating roller 25.

  On the other hand, in the sheet bank 200, sheets S as recording media are stacked and stored. A calling roller 27, a supply roller 28, and a separation roller 29 are provided to form a supply path R 1 that leads to the sheet conveyance path R of the image forming apparatus main body 100.

  Now, when forming an image using this image forming apparatus, a main switch (not shown) is turned on and then a start switch (not shown) is pressed. Then, the photosensitive member 10 is rotated clockwise by a photosensitive member driving motor (not shown) at a predetermined timing, the surface is uniformly charged by the charging device 11, and then the laser beam L is irradiated by an exposure device (not shown). Optical writing is performed to form an electrostatic latent image on the surface of the photosensitive member 10, and then the developing device 12 attaches toner by the developing roller 16 to visualize the electrostatic latent image.

  Further, when the start switch is pressed, the sheet S is sent out by the calling roller 27 in the sheet bank 200 at a predetermined timing, and the image is supplied from the supply path R1 while being separated and conveyed one by one by the subsequent supply roller 28 and separation roller 29. The sheet is placed in the sheet conveyance path R of the forming apparatus main body 100, conveyed by the pair of conveyance rollers 23, and abutted between the pair of registration rollers 22 and stopped. Then, the registration roller 22 is rotated in synchronization with the above-described toner image on the photoconductor 10 and sent to the lower transfer position of the photoconductor 10.

  Then, the toner image on the photoreceptor 10 is transferred to the sheet S fed to the transfer position by the transfer device 13 to form an image. The sheet S after the image transfer is conveyed by the transfer belt 20 and guided to the fixing device 24. The sheet S passes between the rotating heating roller 25 and the pressure roller 26 and is conveyed by both the rollers while applying heat and pressure. After fixing the toner image, the toner image is discharged out of the image forming apparatus main body 100.

  On the other hand, the residual toner on the photoconductor 10 after image transfer is removed by the cleaning device 14 to clean the surface of the photoconductor 10, and the residual potential on the photoconductor 10 is removed by the static eliminator 15 to start from charging. Prepare for image formation.

  FIG. 2 shows a process cartridge P provided in the image forming apparatus main body 100 shown in FIG.

  As shown in FIG. 2, in the illustrated example, the above-described photoreceptor 10, charging device 11, developing device 12, cleaning device 14, and static eliminator 15 are housed and integrated in one cartridge case 30 to reduce the size. At the same time, the process cartridge P is formed in order to improve maintainability. Then, the image forming apparatus main body 100 is detachable in a lump.

  By the way, as can be seen from FIG. 2, the cleaning device 14 is provided with an opening 33 on the photosensitive member 10 side of the cleaning case 32, and a base edge of the cleaning blade 35 is attached to the upper edge of the opening via a blade holder 34. The edge is pressed against the peripheral surface of the photoconductor 10.

  FIG. 3 shows the positional relationship between the photoconductor 10 provided in the process cartridge P and the cleaning blade 35 of the cleaning device 14.

  As shown in FIG. 3, the leading edge of the cleaning blade 35 is pressed against the peripheral surface of the photoconductor 10. Then, along with the rotation of the photoconductor 10 as the image carrier, the toner remaining on the photoconductor 10 after the image transfer is removed using the cleaning blade 35. The general dimensions of the cleaning blade 35 are a width a of 320 mm, a length b of 10 mm, and a thickness c of 2 mm.

  In the present invention, the cleaning device 14 is provided with a frictional force detecting means for detecting the frictional force of the cleaning blade 35 against the photosensitive member 10 as an image carrier.

FIG. 4 shows the configuration of the cleaning device 14 according to the present invention.
In the example shown in FIG. 4, the frictional force detecting means 42 is configured by the pressure-sensitive element 40 attached to the cleaning blade 35 and the detection circuit 41 that detects a change in electrical characteristics thereof. A control circuit 43 is connected to the detection circuit 41 of the frictional force detection means 42, and a cleaning blade drive means 44 is connected via the control circuit 43.

  Then, the frictional force of the cleaning blade 35 against the photosensitive member 10 is directly detected by the frictional force detecting means 42, and the cleaning blade driving means 44 is feedback-controlled by the control circuit 43 based on the fluctuation pattern of the frictional force based on the output signal of the detection circuit 41. Then, the cleaning blade 35 is driven in the Y direction by the cleaning blade driving means 44 to change the contact pressure of the cleaning blade 35 with respect to the photoreceptor 10.

FIG. 5 shows an example of how the pressure sensitive element 40 is attached to the cleaning blade 35.
The pressure-sensitive element 40 in the illustrated example is made of rubber, has a rectangular shape, and is attached to both sides of the back surface of the cleaning blade 35 using an elastic adhesive so as not to prevent the blade from being deformed. Of course, the number is not limited to two and may be one or three or more.

In FIG. 6, the other example of the attachment state of the pressure sensitive element 40 is shown.
As shown in FIG. 6 (A), the pressure sensitive element 40 is attached to the cleaning blade 35, and the back-up material 45 is attached to the back surface of the pressure sensitive element 40 as shown in FIG. 6 (B). As shown, the pressure sensitive element 40 may be sandwiched between the cleaning blade 35 and the backup material 45 to increase the detection output.

  As the backup material 45, a material having high rigidity is used so as not to be deformed. Accordingly, the resistance is not changed by the deformation compressive force generated when the cleaning blade 35 is deformed, but the sensitivity is increased by increasing the resistance change amount by compressive deformation that reduces the volume in the thickness direction.

  FIG. 7 shows an output pattern of the frictional force detection means 42 when normal cleaning and poor cleaning development occur.

  In the normal cleaning state, the pressure is almost constant and shows a small pressure fluctuation. However, when a cleaning failure occurs, the toner slips through, causing the pressure to drop for a moment, indicating a pressure fluctuation with no regularity. In such a variation pattern, the cleaning blade driving means 44 is driven to increase the contact pressure of the cleaning blade 35 with respect to the photoreceptor 10 so that good cleaning performance can be obtained.

FIG. 8 shows another output pattern of the frictional force detection means 42.
As shown in FIG. 8, when a pressure higher than the output pattern in the normal cleaning state is regularly generated, chattering occurs, and particularly when the pressure is severe, blade squeal occurs. At this time, no defective cleaning occurs, but it becomes a problem as noise. Therefore, in the case of such a variation pattern, the cleaning blade driving unit 44 is driven to move the cleaning blade 35 in a direction in which the contact pressure with respect to the photoreceptor 10 is weakened.

  In addition, there may be a case where a stable value is shown while slightly fluctuating with a pressure smaller than the output pattern in the normal cleaning state. In such a variation pattern, filming occurs and cleaning is performed, but the toner hardly adheres to the photosensitive member 10 during development, resulting in development failure. This is because the toner resin is fixed to the photosensitive member 10 by being pressed by the development pressure.

FIG. 9 shows a control block diagram when filming is detected.
When filming occurs, for example, as shown in FIG. 9A, control is performed by the control circuit 43 based on the output signal of the detection circuit 41 of the frictional force detection means 42, for example, an alarm provided on the operation panel. The notification means 47 is driven to notify that it is time to replace the photosensitive member 10.

  For example, as shown in FIG. 9B, based on the output signal of the detection circuit 41 of the frictional force detection means 42, the filming blade driving means 48 is driven under the control of the control circuit 43. The ming removal blade is brought into contact with and separated from the photoreceptor 10.

  By the way, in the above-described example, the case where the frictional force detecting means 42 is configured by the pressure-sensitive element 40 attached to the cleaning blade 35 and the detection circuit 41 that detects a change in its electrical characteristics has been described. However, the frictional force detecting means 42 may have another configuration.

  FIG. 10 is an enlarged view of a part of the cleaning blade 35 used in the frictional force detecting means 42 having another configuration.

The cleaning blade 35 shown in FIG. 10 includes an insulating rubber material 50 and conductive particles 51. The frictional force detecting means 42 is composed of conductive particles 50 that are distributed in the cleaning blade 35 and a detection circuit that detects a change in electrical characteristics of the cleaning blade 35. In the natural state, as shown in the drawing, the conductive particles 51 are almost uniformly dispersed in the rubber material 50 and are not in contact with each other, and no conduction path is formed. ^It shows a very high electric resistance value of ⁷ Ω or more.

FIG. 11 shows a state where pressure is applied to the cleaning blade 35.
When pressure is applied to the cleaning blade 35 shown in FIG. 10, a conduction path is formed as shown in FIG.

FIG. 12 shows the relationship between the load F and the resistance R of the cleaning blade shown in FIG.
As can be seen from FIG. 12, when the pressure is reduced and no pressure is applied, the restoring force of the cleaning blade 35 returns to the state shown in FIG. 10, and the electrical resistance value becomes 10 ⁷ Ω or more. On the other hand, when the pressure is applied, the electrical resistance value decreases rapidly.

  In addition, the outer side of the rubber material 50 is covered with polyurethane used for a general blade material to form a double structure, so that the wear resistance can be improved.

FIG. 13 shows a cleaning blade 35 and a detection circuit used in the frictional force detection means 42 of still another configuration.
In the example shown in FIG. 13, the frictional force detection means 42 is configured on the cleaning blade 35 by forming a detection circuit with the resistive thin film 53. The resistive thin film 53 has a configuration in which Ta, Ta—N, Ta—Si, Ni—Cr, Ta—Al, etc. are deposited to form a bridge circuit as shown in FIG. And

FIG. 14 shows a cleaning blade 35 used in the frictional force detecting means 42 of still another configuration.
The frictional force detection means 42 includes a strain sensor 54 attached to the cleaning blade 35 and a detection circuit 41 that detects a change in its electrical characteristics. The strain sensor 54 in the illustrated example has a rectangular shape, and is attached to both sides of the back surface of the cleaning blade 35 using an elastic adhesive so as not to prevent the blade from being deformed. The number of strain sensors 54 is not limited to two, and may be one or three or more.

  FIG. 15 shows the difference in detection output of the frictional force detection means 42 depending on the presence / absence of an image pattern.

  The image on the photoconductor 10 is transferred to the sheet S at the transfer position. At this time, the toner transfer rate is about 95%, and the remaining 5% of the remaining toner is removed from the surface of the photoconductor 10 by the cleaning device 14. To do. However, since the remaining toner is 0% in the area where there is no image pattern, the frictional force of the cleaning blade 35 against the photoconductor 10 is naturally different from the area where there is no image pattern. This becomes an output error of the frictional force detecting means 42, resulting in control variation. Therefore, it is necessary to eliminate such an input error to the frictional force detecting means 42 to eliminate the output error and to eliminate the control variation.

FIG. 16 shows an example for eliminating the output error of the frictional force detecting means 42.
As shown in FIG. 16, apart from the normal image patterns 56 and 57, etc., a constant image pattern 58 such as a solid image is formed on the photosensitive member 10 in the circumferential direction of the photosensitive member 10, and the fixed image is displayed. The pressure sensitive element 40 is affixed to the cleaning blade 35 so as to face the pattern forming position, and the frictional force of the cleaning blade 35 with respect to the photoconductor 10 at the fixed image pattern forming position is detected by the frictional force detecting means 42. Control is performed based on the output signal of the detection means 42.

  By doing so, it is possible to eliminate the influence of the image pattern, improve the detection accuracy, and exhibit better cleaning performance.

FIG. 17 shows another example of the image forming apparatus according to the present invention.
In the image forming apparatus described above, the case where the present invention is applied to an image forming apparatus including one process cartridge has been described. However, the present invention can also be applied to a color image forming apparatus having a plurality of process cartridges as shown in FIG. 17, for example.

  In the color image forming apparatus shown in FIG. 17, a sheet conveyance belt 62 is wound around rollers 60 and 61 so as to be able to run in the horizontal direction, and magenta, cyan, yellow and black process cartridges Pm are placed on the sheet conveyance belt 62. , Ps, Py, and Pb are arranged in a tandem manner. Each process cartridge is provided with a photoconductor 10 in the same manner as described above, and is provided with a charging device 11, a developing device 12, a cleaning device 14, a static elimination device (not shown), and the like around the photoconductor 10.

  A transfer device 13 is provided around each photosensitive member 10 with a sheet conveying belt 62 interposed therebetween, and transfer positions of magenta, cyan, yellow, and black are formed. A belt cleaning device 21 is disposed around the sheet conveying belt 62.

  Below the sheet conveyance belt 62, the sheets S are stacked and stored, and a calling roller 27, a supply roller 28, and a separation roller 29 are provided. The sheet S is guided from there to the sheet conveyance belt 62, and each transfer position is set. A sheet conveyance path R is formed through which the sheet is discharged from the discharge port to the outside. A fixing device 24 is provided in front of the discharge port of the sheet conveyance path R.

  Then, the sheet S is sent out by the calling roller 27, separated one by one by the subsequent supply roller 28 and separation roller 29, guided to the sheet conveying belt 62 through the sheet conveying path R, and transferred while being conveyed by the sheet conveying belt 62. The toner images of magenta, cyan, yellow, and black are sequentially transferred at the position to form a composite color image, the transferred image is fixed by the fixing device 24, and the sheet S on which the image is recorded is discharged from the discharge port to the outside.

  In each of the process cartridges Pm, Ps, Py, Pb, the residual toner on the photoconductor 10 after image transfer is removed by the cleaning device 14 to clean the surface of the photoconductor 10, and the residual potential on the photoconductor 10 is removed by the static eliminator. To prepare for the next image formation starting from charging.

  Also in this example, the cleaning device 14 for each process cartridge Pm, Ps, Py, Pb is provided with a frictional force detecting means for detecting the frictional force of the cleaning blade 35 against the photosensitive member 10.

  As a result, poor cleaning due to slipping of toner, blade noise and chatter occurring between the photoconductor 10 and the cleaning blade 35, blade turning up of the cleaning blade 35, and toner additives and paper dust adhere to the surface of the photoconductor 10. Toners that occur on the photoconductor 10 after image transfer using the cleaning blade 35 are discovered by controlling defects as needed, such as occurrence of filming, and appropriately controlling them. Is effectively removed.

1 is an overall schematic configuration diagram of an internal mechanism of an electrophotographic image forming apparatus according to the present invention. FIG. 2 is an enlarged configuration diagram of a process cartridge provided in the image forming apparatus main body illustrated in FIG. 1. FIG. 6 is a perspective view showing a positional relationship between a photoconductor provided in the process cartridge and a cleaning blade of a cleaning device. It is a block diagram of the cleaning apparatus by this invention. It is a perspective view which shows the example of the attachment state of the pressure sensitive element with respect to the cleaning blade. FIG. 6 shows another example of the pressure sensor mounting state, (A) is a state diagram in which the pressure sensitive device is mounted on the cleaning blade, (B) is a state diagram in which a back-up material is subsequently mounted on the back surface of the pressure sensitive device, (C ) Is an overall side view at that time. It is a figure which shows the output pattern of the frictional force detection means when normal cleaning and poor cleaning development occur. It is a figure which shows another output pattern of a frictional force detection means. FIG. 6 is a control block diagram when the occurrence of filming is detected. (A) shows a case where notification is given by the notification means, and (B) shows a case where filming is removed by a removal blade. It is the elements on larger scale of the cleaning blade used with the frictional force detection means of another structure. It is the elements on larger scale which show the state which applied the pressure to the cleaning blade. FIG. 11 is a relationship diagram between the load and resistance of the cleaning blade shown in FIG. 10. (A) is a perspective view of a cleaning blade used in a frictional force detecting means of still another configuration, and (B) is a detection circuit diagram thereof. FIG. 10 is a perspective view of a cleaning blade used in a frictional force detecting unit having still another configuration. It is a figure which shows the difference in the detection output of the frictional force detection means by the presence or absence of an image pattern. FIG. 5 is a perspective view of a photoconductor and a cleaning blade, illustrating an example of eliminating an output error of a frictional force detection unit. It is a whole schematic block diagram of the internal mechanism in the other example of the image forming apparatus which concerns on this invention.

Explanation of symbols

10 Photoconductor (image carrier)
DESCRIPTION OF SYMBOLS 14 Cleaning apparatus 35 Cleaning blade 40 Pressure sensitive element 41 Detection circuit 42 Frictional force detection means 44 Cleaning blade drive means 47 Notification means 48 Removal blade drive means 51 Conductive particle 53 Resistance thin film 54 Strain sensor 58 Constant image pattern P Process cartridge

Claims (12)

In a cleaning device for removing toner remaining on an image carrier after image transfer using a cleaning blade,
A cleaning device, comprising: a friction force detecting means for detecting a friction force of the cleaning blade with respect to the image carrier.   The cleaning apparatus according to claim 1, wherein the frictional force detection unit includes a pressure-sensitive element attached to the cleaning blade and a detection circuit that detects a change in electrical characteristics thereof.   2. The cleaning according to claim 1, wherein the frictional force detecting means includes conductive particles provided dispersed in the cleaning blade, and a detection circuit that detects a change in electrical characteristics of the cleaning blade. apparatus.   2. The cleaning apparatus according to claim 1, wherein the frictional force detection means is configured on the cleaning blade by forming a detection circuit with a resistive thin film.   The cleaning apparatus according to claim 1, wherein the frictional force detection unit includes a strain sensor attached to the cleaning blade and a detection circuit that detects a change in electrical characteristics thereof.   6. The cleaning blade driving means for driving the cleaning blade based on an output signal of the detection circuit to change a contact pressure of the cleaning blade with respect to the image carrier. 2. The cleaning device according to 1.   The cleaning apparatus according to claim 1, further comprising a notification unit that notifies a replacement timing of the image carrier based on an output signal of the detection circuit.   6. The cleaning device according to claim 1, further comprising a removal blade driving unit that contacts and separates the filming removal blade from the image carrier based on an output signal of the detection circuit.   A constant image pattern is formed on the image carrier, and the frictional force of the cleaning blade against the image carrier at the constant image pattern forming position is detected by a frictional force detection means, and an output signal of the frictional force detection means And a cleaning blade for removing toner remaining on the image carrier after image transfer using a cleaning blade.   A process cartridge comprising the cleaning device according to claim 1.   An image forming apparatus comprising the cleaning device according to claim 1.   An image forming apparatus comprising a plurality of process cartridges according to claim 10.

Images