JP3673736B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a cleaning for cleaning the surface of an image carrier in a printer, a copying machine, a facsimile, or the like.Equipped with equipmentThe present invention relates to an image forming apparatus.
[0002]
[Prior art]
2. Description of the Related Art A cleaning device in an image forming apparatus such as a printer, a copying machine, or a facsimile is known that has a cleaning blade as a cleaning member for cleaning an image carrier.
[0003]
For example, in an electrophotographic image forming apparatus, a toner image is formed on a photosensitive drum (image carrier) through image forming processes such as a charging process, an exposure process, and a developing process, and the toner image is exposed by a transfer process. It is transferred from the body drum onto a transfer material (for example, paper). In this transfer process, not all of the toner constituting the toner image on the photosensitive drum is transferred, and a small amount of toner remains on the surface of the photosensitive drum. The toner remaining on the surface of the photosensitive drum in this manner (hereinafter referred to as “residual toner”) is removed by the above-described cleaning blade.
[0004]
As shown in FIG. 14, the edge 61 a of the cleaning blade 61 is brought into contact with the surface of the photosensitive drum 11, thereby scraping off residual toner adhering to the surface of the photosensitive drum 11.
[0005]
[Problems to be solved by the invention]
However, the conventional example described above has the following problems.
[0006]
As shown in FIG. 14, residual toner scraped from the surface of the photosensitive drum 11 is aggregated in the vicinity of the edge 61 a of the cleaning blade 61 that is in contact with the photosensitive drum 11. Normally, the aggregated residual toner falls into a cleaning container (not shown) of the cleaning device with a certain size, so that there is no problem.
[0007]
However, depending on the influence of the increase in the peripheral speed (process speed) of the photosensitive drum 11 due to the recent increase in the speed of the image forming apparatus and the environmental conditions, the aggregated residual toner (hereinafter referred to as aggregated mass) does not drop and grows. It has been found that a phenomenon occurs in which the nip N of the edge 61a of the cleaning blade 61 passes through. The problem is that the residual toner slipped through in this way is transferred to the subsequent transfer material (sheet material) in the form of a streak during the next image formation, resulting in an image defect.
[0008]
On the other hand, in an environment other than a low-humidity environment where the temperature is 25 ° C. and the humidity is 50%, when the image forming operation is not performed, the humidity is high, so that moisture including ozone and the like generated by image formation is present. As a result, there is a problem that a part of the photosensitive drum is not charged when an image forming operation is performed. As a countermeasure, there is a countermeasure of heating the photosensitive drum to evaporate the moisture on the surface. Furthermore, when using a blade whose temperature characteristics are optimal at around 30 ° C, the function of the cleaning blade may not be fully demonstrated even in a normal temperature environment of 23 ° C. Arise. From the above, a method of heating the photosensitive drum can be considered.
[0009]
However, when the temperature of the photosensitive drum is high, the toner near the edge of the cleaning blade tends to aggregate. The cause is considered to be that the aggregation between the toners becomes strong because the toners are in a molten state as the temperature rises due to the thermal characteristics of the toners. Further, in recent years, low-melting toners are used for energy saving, and this tendency becomes remarkable in such low-melting toners. On the other hand, it is considered that when the humidity is low, the electrostatic attraction between the toners increases, and the degree of aggregation between the toners increases.
[0010]
Further, as a means for improving the cleaning performance of the cleaning blade, there is a method of applying a vibration by a piezoelectric element to the cleaning blade as proposed in JP-A-6-4014 and JP-A-11-174922. However, in this method, since the piezoelectric element is attached to the cleaning blade that deteriorates due to durability, the piezoelectric element is also replaced at the same time when the deteriorated cleaning blade is replaced, resulting in an increase in cost. In addition, there is a drawback that it is difficult to give sufficient vibration to remove the aggregates that have agglomerated and grown. Further, the method of applying collision vibration to the cleaning blade as proposed in Japanese Patent Laid-Open No. 9-160455 may be able to give sufficient vibration to remove agglomerates, Depending on the behavior of the cleaning blade at the time of input, there may be adverse effects such as slipping of residual toner.
[0011]
Japanese Patent Laid-Open No. 2000-112187 discloses that when continuous image formation is greater than or equal to a predetermined number of sheets, the rotation of the photosensitive drum is temporarily stopped for each predetermined number of image formations so that the shape of the cleaning member is The shape of the nip portion between the photosensitive drum and the cleaning member changes due to a slight change during the stop from the rotation. As a result, there is also considered a method in which the rotation of the photosensitive drum is temporarily stopped to change the shape of the nip portion, whereby the toner fixed to the nip portion can be dropped from the nip portion. In this method, it is possible to remove the light agglomerates generated when the image is formed intermittently. However, it is difficult to completely remove the agglomerates that continue to grow in the continuous image formation.
[0012]
Further, when a means for providing a method for removing agglomerates is introduced into a product, it is indispensable to reduce the cost to extend the life.
[0013]
  Accordingly, the present invention has been made in view of the above-described circumstances, and it has been attempted to extend the life of the means for applying vibration to the cleaning member, and also agglomerates at the nip portion of the cleaning member that is in contact with the surface of the image carrier. Cleaning that can remove residual toner wellEquipped with equipmentAn object of the present invention is to provide an image forming apparatus.
[0014]
[Means for Solving the Problems]
  To achieve the above purposeA typical configuration of the present invention includes an image carrier, a transfer unit that transfers a toner image formed on the image carrier to a transfer material, a fixing unit that fixes the toner image to the transfer material, and the image carrier. An image forming apparatus comprising: a cleaning member that contacts a body to remove transfer residual toner; and a vibration unit that vibrates the cleaning member. A heating unit that heats the image carrier when the power is turned off, and the fixing unit Detecting means for detecting the temperature of the image bearing member, and control means for controlling the number of vibration operations to be executed when the image carrier is stopped according to the temperature detected by the fixing means. The temperature detected by the fixing means is a predetermined temperature. In the following cases, the vibration operation is executed a plurality of times.
[0016]
  According to the above configuration, it is possible to extend the life of the excitation means that applies vibration to the cleaning member, andImage carrier surfaceAt the nip of the cleaning member in contact withAggregated residual tonerCan be removed satisfactorily.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition,In the following description, first a reference example will be described, and then an embodiment according to the present invention will be described. Also,In the drawings, the same reference numerals denote the same configuration or action, and repeated descriptions thereof are omitted as appropriate.
[0018]
[Reference example]
  Reference examples with reference to the drawingsAn image forming apparatus provided with the cleaning device according to the above will be described in detail.
[0019]
[Image forming apparatus]
  FIG. 1 shows an image forming apparatus.An example is shown. The image forming apparatus shown in the figure is a laser beam printer, and the figure is a longitudinal section showing a schematic configuration thereof. In the following, a case where the cleaning target object to be cleaned by the cleaning device 17 (described later) according to the present invention is the photosensitive drum 11 will be described as an example.
[0020]
The laser beam printer (hereinafter referred to as “image forming apparatus”) shown in FIG. 1 includes a printer unit (image forming unit) 1 and a reader unit (image reading unit) 2.
[0021]
Among them, the printer unit 1 is provided with a drum-type electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 11 as an image carrier, and around the photosensitive drum 11, its rotating direction ( A primary charger (primary charging means) 12, an exposure device (exposure means) 13, a developing device (developing means) 14, a transfer charger 15, a separation charger 16, and a cleaning device (cleaning means) are sequentially arranged along the arrow direction. ) 17 is provided. Further, in the order from the upstream side along the conveying direction of the transfer material (for example, paper) P, the sheet feeding cassettes 18a and 18b, the sheet feeding rollers 19a and 19b, the registration rollers 20, the conveying belt 21, the fixing roller 22a, and the pressure roller. A fixing device (fixing means) 22 having 22b and a discharge roller 23 are disposed.
[0022]
On the other hand, the reader unit 2 is provided with a platen glass 31, a document pressing plate 32, a light source 33, reflection mirrors 34a, 34b, 34c, a lens 35, a CCD (photoelectric conversion element) 36, an image processing unit 37, and the like. .
[0023]
  In the image forming apparatus having the above-described configuration, in the printer unit 1, the photosensitive drum 11 is driven in a direction indicated by an arrow by a driving unit (not shown).hereIt is rotationally driven at 480 mm / sec, and its surface is uniformly charged to a predetermined polarity and potential by the primary charger 12. On the other hand, in the reader unit 2, a document (not shown) placed on the platen glass 31 and pressed by the document pressing plate 32 is irradiated with the image surface (lower surface) by the light source 33, and the reflected light is reflected. The light is reflected by the mirrors 34 a, 34 b and 34 c, further passes through the lens 35, and is input to the CCD 36. The light thus input to the CCD 36 is subjected to various well-known image processing by the image processing unit 37, is converted into an electric signal 38, and is input to the exposure device 13 on the printer unit 1 side as image information.
[0024]
The laser scanner 13a of the exposure device 13 is modulated according to the image information, and exposes the surface of the photosensitive drum 11 after the above-described exposure via the reflection mirror 13b. By this exposure, an electrostatic latent image is formed on the surface of the photosensitive drum 11.
[0025]
This electrostatic latent image is developed by the developing device 14. A developer (toner) is stored in the developing device 14, and this toner is attached to the electrostatic latent image on the surface of the photosensitive drum 11 by applying a developing bias to the developing sleeve 14a, and the electrostatic latent image. The image is developed as a toner image.
[0026]
The toner image thus formed on the photosensitive drum 11 is transferred to the transfer material P. The transfer material P is fed from the paper feed cassette 18a or the paper feed cassette 18b by the paper feed roller 19a or the paper feed roller 19b. It is supplied to a transfer portion between the body drum 11 and the transfer charger 15. The toner image on the photosensitive drum 11 is transferred onto the transfer material P by applying a transfer bias to the transfer charger 15.
[0027]
The transfer material P after the toner image is transferred is separated from the surface of the photosensitive drum 11 by the separation charger 16 and is transported to the fixing device 22 by the transport belt 21, where it is heated and pressed by the fixing roller 22a and the pressure roller 22b. After the toner image is fixed on the surface, it is discharged out of the image forming apparatus main body by the discharge roller 23.
[0028]
On the other hand, after the toner image is transferred, the residual toner (adhered matter) remaining on the surface of the photosensitive drum 11 that is not transferred to the transfer material P at the time of transfer is removed by the cleaning device 17 and used for the next image formation. The cleaning device 17 will be described in detail later.
[0029]
In FIG. 1, two automatic document feeders 39 for automatically supplying a document on the platen glass 31 and automatically discharging the document from the platen glass 31 are provided above the document pressing plate 32. It is indicated by a dotted line.
[0030]
Reference numeral 71 denotes temperature detecting means for detecting the temperature of the outside air. Reference numeral 72 denotes humidity detection means for detecting the humidity of the outside air. The detection information of the temperature detection means 71 and the humidity detection means 72 is sent to a control circuit 55 as a control means shown in FIG. 5, which will be described later, and the control circuit 55 generates vibration means based on the detection information. The operation of 51 is controlled.
[0031]
[Cleaning device]
Next, the cleaning apparatus 17 according to the present invention will be described in detail with reference to FIG. FIG. 2 is a longitudinal sectional view of the cleaning device 17 in a direction perpendicular to the longitudinal direction (axial direction) of the photosensitive drum 11.
[0032]
The cleaning device 17 includes a frame (first frame) 41, a frame (second frame) 42, a cleaning blade (cleaning member) 43, a magnet roller 44, a conveying screw 45, a sheet 46, a holder 47, shafts 48 and 49, A tension spring (biasing means) 50 and a vibration means 51 are provided.
[0033]
Of these, the cleaning blade 43 is formed of a plate-like elastic body, and is held so as to be sandwiched between the frame 41 and the holder 47 by screwing the holder 47 to the frame 41. The cleaning blade 43 has one edge 43 a in contact with the surface of the photosensitive drum 11. The contact direction is the counter direction with respect to the movement direction (arrow direction) of the surface of the photosensitive drum 11. The contact surface 41a of the frame 41 with the back surface of the cleaning blade 43 and the contact surface 47a of the holder 47 with the end surface of the cleaning blade 43 are processed with high accuracy and are arranged with high positional accuracy. Therefore, the cleaning blade 43 can be realized with high positional accuracy with respect to the photosensitive drum 11 by being sandwiched by the holder 47 in a state where a part of the cleaning blade 43 is in contact with the contact surfaces 41a and 47a. Yes. The frame 41 holding the cleaning blade 43 also holds the vibration means 51.
[0034]
  The frame 41 is swingably attached to the frame 42 via a shaft 48.hereAlthough the photoconductor drum can swing in the longitudinal direction, a configuration in which the photoconductor drum does not swing in the longitudinal direction is also possible. One end of the tension spring 50 is connected to a part of the frame 42, and the other end is attached to a part of the frame 41. Therefore, the frame 41 is urged counterclockwise in the figure by the tension spring 50 around the shaft 48. Accordingly, the edge 43a of the cleaning blade 43 is in contact with the surface of the photosensitive drum 11 with an appropriate pressing force.
[0035]
The frame 42 extends downward on the side far from the photoconductive drum 11 and extends toward the photoconductive drum 11 at the bottom. The magnet roller 44 and the conveying screw 45 are rotatably supported by this portion of the frame 42. The magnet roller 44 and the conveying screw 45 are rotationally driven by driving means (not shown).
[0036]
The magnet roller 44 is disposed below the cleaning blade 43, and forms a toner layer of residual toner scraped off by the cleaning blade 43 on the surface thereof. The toner layer thickness is regulated by the sheet 46 and the shaft 49. The magnet roller 44 recoats the toner on the surface of the photosensitive drum 11 by bringing the toner layer into contact with the longitudinal direction of the photosensitive drum 11 (the direction along the generatrix). This is an adverse effect when the residual toner is scraped off by the cleaning blade 43 without recoating, that is, the frictional force between the cleaning blade 43 and the photosensitive drum 11 differs depending on whether the residual toner is present or not. This is to prevent the negative effect that unnecessary chatter (fine vibration) occurs. By recoating the residual toner in the longitudinal direction of the photosensitive drum 11 in this manner, the frictional force between the cleaning blade 43 and the photosensitive drum 11 can be stabilized in the longitudinal direction, and chattering of the cleaning blade 43 can be prevented. . The residual toner is scraped off by the cleaning blade 43 together with the recoated toner, and is collected by the magnet roller 44.
[0037]
The rotation direction of the magnet roller 44 is preferably forward with respect to the photosensitive drum 11 as shown in FIG. 2, but the same effect can be obtained when it is in the reverse direction with respect to the photosensitive drum 11. Is possible.
[0038]
The sheet 46 is in contact with the shaft 49. The sheet 46 is collected by the magnet roller 44 and has a function of sending excess residual toner to the conveying screw 45 to form a toner layer. The conveying screw 45 conveys residual toner to a toner collecting container (not shown).
[0039]
[Heating means]
  FIG. 3 shows the heating means 81.thisThe heating unit 81 mainly heats the photosensitive drum 11, and the temperature detection unit 82 controls the temperature of the photosensitive drum 11 heated by the heating unit 81.hereThe temperature heated and controlled by the heating means 81 is 40 ° C.thisThe heating means 81 is of a cylindrical type and covers the inside of the photosensitive drum 11. Of course, there is no problem with other types of heating means.
[0040]
[Excitation means]
  FIG. 5 shows the vibration means.The structure of 51 is shown.
[0041]
The vibration means 51 includes a motor 52, a weight 53 attached to the output shaft 52a, and a case 54. The motor 52 is housed and fixed in the above-described case 54 in a state where it is connected to a control circuit 55 serving as control means. Further, the case 54 with the motor 52 fixed inside is fixed to the frame 41 as shown in FIG. Since the weight 53 is fixed in a state where the center of gravity is biased to one side with respect to the output shaft 52 a, vibration is generated from the motor 52 when the output shaft 52 a of the motor 52 is rotationally driven by the control circuit 55. This vibration propagates to the case 54 and the frame 41 and further to the cleaning blade 43. The case 54 has a function of preventing toner from entering the motor 52 and a function of efficiently transmitting vibration to the frame 41 by restraining the motor 52. The control circuit 55 is also connected to a drum motor 56 for driving the photosensitive drum 11 to rotate, and controls the rotation of the photosensitive drum 11.
[0042]
The vibration means 51 having the above-described configuration is not limited to the above-described configuration as long as it can apply sufficient vibration to the cleaning blade 43 to remove agglomerates.
[0043]
Further, even if one vibration means 51 is arranged at the center in the longitudinal direction of the frame 41 of the cleaning device 17, it is effective. However, in this case, the vibration is effectively propagated to the end of the cleaning blade 43. Requires a lot of vibration. For this reason, as shown in FIG. 6, by arranging a plurality of excitation means 51 at both ends in the longitudinal direction of the frame 41, the vibration can be propagated to the cleaning blade 43 evenly with a relatively small vibration. It becomes possible. In this case, the vibration means 51 is arranged at a position distributed to both ends with respect to the center L in the longitudinal direction of the frame 41 so that the variation in the contact pressure of the cleaning blade 43 to the photosensitive drum 11 is reduced. It is desirable to do so.
[0044]
  Note that the cleaning performance of the above-described cleaning blade 43 gradually decreases due to wear associated with long-term use. Therefore, replacement is necessary at an appropriate time. Even at this timeConfiguration as described aboveThen, only the cleaning blade 43 can be easily replaced simply by removing the holder 47. In addition to minimizing the cost of parts required for replacement and the number of replacement steps, the contact surface 41a of the frame 41 can be reduced. Since the mounting surface accuracy of the cleaning blade 43 can be guaranteed by the surface accuracy, it is devised to increase the stability. In order to increase the reproducibility of the behavior of the cleaning blade 43 when vibration is input by the vibration means 51, it is important that the mounting state is stable.
[0045]
[Blade edge]
  4 (a), (b), (c), (d)And photosensitive drum11 is an enlarged view of a contact portion (nip) N between the surface 11 and the edge 43 a of the cleaning blade 43.
[0046]
As shown in FIG. 4A, residual toner scraped off from the surface of the photosensitive drum 11 is aggregated at the edge 43 a of the cleaning blade 43 that is in contact with the photosensitive drum 11. As shown in FIG. 4B, when the aggregated residual toner continues to grow, the toner passes through the nip N between the edge 43a of the cleaning blade 43 and the surface of the photosensitive drum 11, and the toner adheres to the transfer material P. As a result, the image may be defective. For this reason, it is necessary to remove the residual toner that has grown into aggregates from the edge 43 a of the cleaning blade 43.
[0047]
Therefore, by operating the vibration means 51 (see FIG. 5) to propagate the vibration to the cleaning blade 43 through the frame 41 (FIG. 4C), an image defect occurs from the edge 43a of the cleaning blade 43. The residual toner aggregates are removed before the process (FIG. 4D). By the way, when the vibration means 51 is operated, the vibration propagates to the photosensitive drum 11 via the cleaning blade 43, and therefore it is not desirable to perform it during image formation. When the vibrating means 51 is operated while the photosensitive drum 11 is rotating, the edge 43a of the cleaning blade 43 is partially separated from the photosensitive drum 11 due to vibration, so that the transfer residual toner on the photosensitive drum 11 is removed from the cleaning blade. 43 slips out of the image and an image defect occurs. Therefore, the timing for operating the vibration means 51 needs to be when the photosensitive drum 11 is completely stopped.
[0048]
When the image forming apparatus shifts from the operation to the stop stage, the photosensitive drum 11 rotates for a while due to inertia until the photosensitive drum 11 is completely stopped. Accordingly, a predetermined time is required from the time when the signal for stopping the photosensitive drum 11 is issued to the time when the photosensitive drum 11 is completely stopped.
[0049]
  there,hereThe operation timing of the vibration means 51 is shown below.
[0050]
[At the time of operation of heating means to the photosensitive drum]
First, an operation example of a heating unit for heating the photosensitive drum will be described. As an example of the operation of the heating means, in an environment other than low humidity, when the image forming operation is not performed, the humidity is high. As a result, when the image forming operation is performed, it is necessary to heat the photosensitive drum to evaporate the moisture on the surface as a countermeasure against the problem that a part of the photosensitive drum is not charged. That was mentioned earlier. Therefore, as a result of experiments on the boundary of humidity, it was found that the above-mentioned problem does not occur when the humidity is less than 20%. Therefore, when the humidity is 20% or more, the heating means can be turned on. is necessary.
[0051]
Therefore, when the humidity detected by the humidity detecting means 72 shown in FIG. 1 is 20% or more, the heating means 81 for the photosensitive drum 11 is turned on when the power is turned on. Therefore, the heating means 81 for the photosensitive drum 11 is turned on not only during the image formation but also when the image forming operation is not performed.
[0052]
As another example of the operation of the heating unit, when the image forming apparatus main body is turned on, the elastic modulus of the cleaning blade decreases because the temperature of the cleaning blade is low depending on the environment. To do. As a result, the cleaning function may not be fully exhibited. And if the process speed is high, this tendency becomes remarkable. Accordingly, when the temperature detected by the temperature detecting means 71 shown in FIG. 1 is 23 ° C. or lower, that is, the so-called normal temperature or lower, the heating means 81 is operated.
[0053]
Furthermore, if the transfer material is continuously passed on one side, the transfer material is at room temperature, so the temperature of the photosensitive drum remains at room temperature, and the temperature of the cleaning blade remains low, so that the cleaning function is sufficient. You may not be able to demonstrate it. Therefore, when the transfer material is continuously passed on one side, the heating means 81 is operated.
[0054]
Note that ON / OFF of the heating unit 81 when the power of the image forming apparatus main body is not turned on can be set in the service mode. When set in the service mode, it is always ON when the power is not turned on.
[0055]
The operation of the heating means is an example, and the heating means may operate depending on the situation in other cases.
[0056]
  hereWhen the heating unit 81 operates as described above, the vibration unit 51 is configured to operate at a timing described later.
[0057]
[sequence]
Hereinafter, the timing at which the vibration means 51 operates will be described. However, the following sequence is an example in which the vibration means 51 operates, and the operation may be performed by selecting any one of the sequences. Of course, the following plural sequences can be selected and operated.
[0058]
(1) When the vibration means is operated first in the morning
For example, when the power is turned on first in the morning, the fixing device temperature does not reach the predetermined temperature in the first morning, so the fixing device reaches the predetermined temperature. Typically, the rollers are heated in a stopped state and then both rollers are idled. When both rollers are idly rotated, the photosensitive drum 11 is also usually rotated at the same time.
[0059]
In this configuration, the timing for operating the vibration means 51 is effective after the photosensitive drum 11 is stopped because it is easy to take the timing. Of course, there is no change with respect to the effect of operating the vibration means 51 before the photosensitive drum 11 rotates.
[0060]
The vibration means operates at the timing as in this example when the heating means 81 operates at night or after the power is turned on.
[0061]
As shown in the timing chart of FIG. 7, energization to the drum motor is stopped after a drum signal for stopping the drum is generated while the drum is rotating. For this reason, the photosensitive drum 11 is stopped, but the rotation due to the inertia of the photosensitive drum 11 remains, so that the photosensitive drum 11 is stopped after a predetermined time A from the absence of energization. The value of the predetermined time A is about 0.5 second to about 2 seconds although it cannot be generally described because it is influenced by the torque of the photosensitive drum, the process speed, and the like. Of course, it is possible to adopt other values without affecting the effect or the like.
[0062]
Therefore, in consideration of the rotation due to the inertia of the photosensitive drum 11, the photosensitive drum 51 is operated by performing the operation of the vibration means 51 after B seconds (predetermined timing) from the time when the drum signal is turned from ON to OFF. 11, the vibration means 51 can be operated.
[0063]
  In addition, C second in FIG. 7 is the operation time of the vibration means 51, and the value is arbitrary.hereThe operation is performed for about 0.7 seconds.
[0064]
Here, the value of B seconds, which is the predetermined timing after the photosensitive drum 11 is stopped, at which the vibration means 51 operates, can be, for example, (A seconds + 0.1 seconds to around 1 second). Here, which value from 0.1 second to 1 second is different depending on the model. Of course, it is possible to adopt a value higher than that without affecting the effect.
[0065]
  D seconds is the time between operations when the vibration means 51 is operated. The value of D is arbitrary,hereFor example, about 1 second. In addition, if this time is D seconds> 0 seconds, there is no effect regardless of which value is adopted.
[0066]
(2) When the image forming operation is interrupted and the vibrating means operates Here, the interruption of the image forming operation will be described. When the continuous image formation is a predetermined number of sheets, for example, 1000 or more continuous image formations,hereFor example, by temporarily stopping the rotation of the photosensitive drum 11 every 1000 image formations, the shape of the cleaning blade 43 slightly changes during the stoppage from the rotation of the photosensitive drum 11. The shape of the nip portion between the body drum 11 and the cleaning blade 43 changes. Thus, once the rotation of the photosensitive drum 11 is stopped, the shape of the nip portion is changed, so that the toner fixed to the nip portion can be dropped from the nip portion. However, in order to further remove the residual toner aggregated on the edge 43a of the cleaning blade 43,hereThe vibration means 51 is operated when the image forming operation is interrupted.
[0067]
The vibration means operates at the timing as in this example when the heating means 81 is always ON during continuous image formation or at some time during continuous image formation. This is the case.
[0068]
As shown in the timing chart of FIG. 8, energization to the drum motor is stopped after a drum signal for stopping and interrupting the drum is generated while the drum is rotating. For this reason, the photosensitive drum 11 stops. However, since the rotation due to the inertia of the photosensitive drum 11 remains, the photosensitive drum 11 stops after a predetermined time A seconds. The value of the predetermined time A is about 0.5 second to about 2 seconds, although it cannot be generally stated because it is affected by the torque of the photosensitive drum 11 and the process speed. Of course, it is possible to adopt other values without affecting the effect or the like.
[0069]
Therefore, in consideration of the rotation due to the inertia of the photosensitive drum 11, the photosensitive drum 51 is operated by performing the operation of the vibration means 51 after B seconds (predetermined timing) from the time when the drum signal is turned from ON to OFF. 11, the vibration means 51 can be operated.
[0070]
  In addition, C second in FIG. 8 is the operation time of the vibration means 51, and the value is arbitrary.hereThe operation is performed for about 0.7 seconds.
[0071]
Here, the value of B seconds, which is the predetermined timing after the photosensitive drum 11 is stopped, at which the vibration means 51 operates, can be, for example, (A seconds + 0.1 seconds to around 1 second). Here, which value from 0.1 second to 1 second is different depending on the model. Of course, it is possible to adopt a value higher than that without affecting the effect.
[0072]
Thereafter, after the operation of the vibration means 51 is completed, the photosensitive drum 11 is rotated again in order to continue the image forming operation after D seconds. Here, although it is the value of D seconds, turning on the drum rotation signal simultaneously with the end of the operation of the vibration means 51 may cause a residual vibration due to the vibration of the vibration means 51, and therefore a predetermined time. It is desirable to have an interval of
[0073]
Therefore, the value of D seconds corresponding to the predetermined time interval may be around 0.1 to 1 second. It should be noted that which value from 0.1 second to 1 second is different depending on the model, and of course, it is possible to adopt a value higher than that without affecting the effect or the like.
[0074]
(3) When vibration means operates during wire cleaning
A sequence in the case of activating the vibration means 51 during the operation of interrupting the image forming operation and cleaning the wire of the corona charger (primary charger 12) is shown.
[0075]
  Here, the operation of interrupting the image forming operation and cleaning the wire of the corona charger will be described. When the continuous image formation is a predetermined number of images, for example, when 2000 or more continuous image formations,hereFor example, it is necessary to clean the wire of the corona charger every 2000 images formed. When the corona charger wire is not cleaned every predetermined number of times, discharge unevenness occurs due to the dirt on the wire, and as a result, problems such as uneven potential on the photosensitive drum 11 and uneven transfer occur. Accordingly, when a predetermined number of sheets are continuously formed, the temporary image forming operation is interrupted to perform such wire cleaning. Therefore,hereIn order to remove the residual toner aggregated on the edge 43a of the cleaning blade 43 by using the interruption of the image forming operation by the wire cleaning, the vibration means 51 is operated.
[0076]
The vibration means operates at the timing as in this example when the heating means 81 is operating during image formation or when it is turned on for some time during continuous image formation. .
[0077]
As shown in the timing chart of FIG. 9, energization to the drum motor is stopped after a drum signal for stopping and interrupting the drum is generated while the drum is rotating. For this reason, the photosensitive drum 11 stops. However, since the rotation due to the inertia of the photosensitive drum 11 remains, the photosensitive drum 11 stops after a predetermined time A seconds. The value of the predetermined time A is about 0.5 second to about 2 seconds, although it cannot be generally stated because it is affected by the torque of the photosensitive drum 11 and the process speed. Of course, it is possible to adopt other values without affecting the effect or the like.
[0078]
Therefore, in consideration of the rotation due to the inertia of the photosensitive drum 11, the photosensitive drum 51 is operated by performing the operation of the vibration means 51 after B seconds (predetermined timing) from the time when the drum signal is turned from ON to OFF. 11, the vibration means 51 can be operated.
[0079]
  In addition, C second in FIG. 9 is the operation time of the vibration means 51, and the value is arbitrary.hereThe operation is performed for about 0.7 seconds.
[0080]
Here, the value of B seconds, which is the predetermined timing after the photosensitive drum 11 is stopped, at which the vibration means 51 operates, can be, for example, (A seconds + 0.1 seconds to around 1 second). Here, which value from 0.1 second to 1 second is different depending on the model. Of course, it is possible to adopt a value higher than that without affecting the effect.
[0081]
Thereafter, the wire cleaning operation of the corona charger is performed after E seconds after the operation of the vibration means 51 is completed. Here, although it is the value of E seconds, there is no problem even if the wire cleaning (wire cleaning means) is turned on simultaneously with the end of the operation of the vibration means 51, and it may be around 0 seconds to 1 second. It should be noted that which value from 0 second to 1 second is different depending on the model, and of course, it is possible to adopt a value higher than that without affecting the effect or the like.
[0082]
  In addition,hereThe procedure for operating the vibration means 51 after the rotation of the photosensitive drum 11 and then performing wire cleaning is used. However, the procedure for performing the wire cleaning after the rotation of the drum and then operating the vibration means 51 is used. However, the effects and the like are the same and no problem occurs.
[0083]
As described above, by operating the vibration means 51 only in an environment of a necessary temperature, it is possible to extend the life of the vibration means 51 and maintain an appropriate image.
[0084]
[First embodiment]
  Next, the present inventionFirst embodimentAn image forming apparatus provided with the cleaning device according to the above will be described in detail. The schematic configuration of the image forming apparatus, the cleaning apparatus, and the vibration means is described above.Reference exampleIt is the same.
[0085]
In this embodiment, when the power of the image forming apparatus is OFF, the heating unit for the photosensitive drum operates. When the power is turned ON, the vibration of the vibration unit is determined according to the temperature of the fixing device. The number of operations is determined, and this is a sequence for the operation of the excitation means. In this embodiment, when the power supply is left off for a long time, the degree of aggregation of the toner near the edge of the cleaning blade becomes higher, so that the toner can be efficiently removed. is there.
[0086]
Therefore, in this embodiment, when the heating unit 81 is operating at night or when the power is turned on, the vibration unit is operated. When the temperature is lower than the temperature, it is recognized that it is first in the morning, and in this case, the vibration means is operated a plurality of times.
[0087]
(2) Fixing device
Here, the fixing device will be described. In FIG. 10, 22a is a fixing roller, 22a1 is a heating means, 22b is a pressure roller, and 22b1 is a metal core. Reference numeral 22c denotes temperature detecting means for detecting the surface temperature of the fixing roller. In the present embodiment, the fixing device having the configuration shown in FIG. 10 is illustrated. However, the fixing device is not limited to this. For example, a fixing device and a film having heating means for the fixing roller and the pressure roller are employed. Even in a fixing device having other temperature detecting means such as a film fixing device and an electromagnetic induction heating fixing device, the present invention has the same effect.
[0088]
Further, the temperature detecting means is not limited to the surface temperature of the fixing roller, and detects the temperature related to other fixing devices such as the surface temperature of the pressure roller, the surface temperature of the film fixing device, the surface temperature near the heater, and the film surface temperature. There is no problem.
[0089]
In the present embodiment, the temperature of the fixing roller is 200 ° C. during image formation, and the temperature that is recognized as the first morning is 170 ° C. or less.
[0090]
Note that the value for determining the temperature of the fixing device of the present embodiment differs depending on the configuration of the image forming apparatus, and thus cannot be determined unconditionally. Even if the value is different from that of the present embodiment, the effect does not change.
[0091]
(3) Timing of operation of the vibration means
(3-1) When the excitation means operates after multiple front rotations
A sequence in the case where the vibration means 51 operates after the previous multi-rotation will be described below.
[0092]
It is assumed that at least when the fixing roller 22a and the pressure roller 22b start to rotate when the temperature detection means 22c of the fixing device 22 reaches a predetermined temperature, at least the photosensitive drum 11 is rotated (hereinafter, the former many) Called rotation). In that case, the timing at which the fixing roller 22a and the like and the photosensitive drum 11 start to rotate does not necessarily have to be the same. In this embodiment, the predetermined temperature is 170 ° C.
[0093]
As shown in the timing chart of FIG. 11, energization to the drum motor is stopped after a drum signal for stopping the drum is generated while the drum is rotating. For this reason, the photosensitive drum 11 is stopped, but the rotation due to the inertia of the photosensitive drum 11 remains, so that the photosensitive drum 11 is stopped after a predetermined time A from the absence of energization. The value of the predetermined time A is about 0.5 second to about 2 seconds, although it cannot be generally stated because it is affected by the torque of the photosensitive drum 11 and the process speed. Of course, it is possible to adopt other values without affecting the effect or the like.
[0094]
Therefore, in consideration of the rotation due to the inertia of the photosensitive drum 11, the photosensitive drum 51 is operated by performing the operation of the vibration means 51 after B seconds (predetermined timing) from the time when the drum signal is turned from ON to OFF. 11, the vibration means 51 can be operated.
[0095]
In addition, C second in FIG. 11 is the operation time of the vibration means 51, and the value is arbitrary. In this embodiment, the operation is performed for about 0.7 seconds.
[0096]
Here, the value of B seconds, which is the predetermined timing after the photosensitive drum 11 is stopped, at which the vibration means 51 operates, can be, for example, (A seconds + 0.1 seconds to around 1 second). Here, which value from 0.1 second to 1 second is different depending on the model. Of course, it is possible to adopt a value higher than that without affecting the effect.
[0097]
D seconds is the time between operations when the vibration means 51 is operated. The value of D is arbitrary, and is set to about 1 second in this embodiment, for example. In addition, if this time is D seconds> 0 seconds, there is no effect regardless of which value is adopted.
[0098]
(3-2) When the vibration means operates before multiple front rotations
A sequence when the vibration means 51 operates before the front multi-rotation will be described below.
[0099]
In the case of this sequence, the vibration means 51 is operated before the pre-multi-rotation, and as the operation timing, the temperature detected by the temperature detection means 22c reaches a predetermined temperature, for example, 150 ° C. When it is time. In this sequence, the operation timing is the temperature of the fixing device. However, even if the operation is performed at a predetermined timing using other signals, the effect of the operation of the vibration means 51 is not affected.
[0100]
As shown in the timing chart of FIG. 12, the photosensitive drum 11 is stopped until the temperature by the temperature detecting means 22c of the fixing device 22 reaches 150.degree. Thereafter, after the temperature by the temperature detection means 22c reaches 150 ° C., the vibration means 51 operates after E seconds. Although the value of E is not a problem even if the vibration means 51 is operated at the same time as the temperature reaches 150 ° C., the value of E is an arbitrary value of 0 seconds or more and there is no problem. In this embodiment, for example, about 0.5 seconds.
[0101]
In FIG. 12, C seconds is the operating time of the vibration means 51, and the value is arbitrary. In this embodiment, the operation is performed for about 0.7 seconds.
[0102]
D seconds is the time between operations when the vibration means 51 is operated. The value of D is arbitrary, and is set to about 1 second in this embodiment, for example. In addition, if this time is D seconds> 0 seconds, there is no effect regardless of which value is adopted.
[0103]
  According to this embodiment, the aforementionedReference exampleIn addition to the above effects, the cleaning blade 43 can be vibrated sufficiently to remove the deposits, and can prevent the deposits from slipping through when the vibration is input to the cleaning blade 43. The deposits on the photosensitive drum 11 can be removed well without a large cost increase.
[0104]
[Second embodiment]
  Next, the present inventionSecond embodimentAn image forming apparatus provided with the cleaning device according to the above will be described in detail. The schematic configuration of the image forming apparatus, the cleaning apparatus, and the vibration means is described above.Reference exampleIt is the same.
[0105]
In the present embodiment, when the vibration unit 51 operates first in the morning when the heating unit 81 operates by the operation of the heating unit 81, the vibration unit 51 depends on the state of the fixing device 22. This is a case where the number of operations is different.
[0106]
That is, in the present embodiment, when the vibration unit 51 is operated by the operation of the heating unit 81, the number of times the vibration unit 51 is operated according to the temperature detected by the temperature detection unit 22c of the fixing device 22. Is determined, and the vibration means 51 is operated by the determined number of times.
[0107]
[Determination of the number of operations of the vibration means]
FIG. 13 shows a flowchart for determining the number of times the vibrating means 51 operates.
[0108]
First, the temperature of the temperature detection means 22c of the fixing device 22 is detected at a predetermined timing. The predetermined timing is, for example, when operating first in the morning, when the power is turned on, when returning from the standby state, when returning after a paper jam occurs in the transport unit, etc., when the error occurs. Time. When the temperature of the fixing device 22 is detected at such a predetermined timing, when the temperature is 150 ° C. or less, the number of operations of the vibration means 51 is five, and when the temperature is 170 ° C. or less, the vibration means 51 is operated. The number of operations is 3 times, and when the temperature is 180 ° C. or less, the number of operations of the vibration means 51 is 1, and when the number is more than 0 ° C. Note that the temperature and number of times are just an example, and of course, the effect does not change even if another temperature and number of times are set.
[0109]
[Operation timing of vibration means]
  In the present embodiment, the sequence in which the vibration means 51 operates for the determined number of times is as described above.First embodimentAs shown in FIG. 5, the configuration of the present embodiment is established as in the case where the vibration means operates.
[0110]
With the above configuration, it is possible to further increase the efficiency of the operation of the vibration means, and not only obtain the same effects as the above-described embodiment, but also the life of the vibration means can be further extended.
[0111]
[Other Embodiments]
In the above-described embodiment, the image forming apparatus capable of forming a monochrome image has been described as an example. However, the present invention is not limited thereto, and the present invention is applicable to a cleaning device for an image forming apparatus capable of forming a color image. The same effect can be obtained even if is applied.
[0112]
In the above-described embodiment, the copying machine is exemplified as the image forming apparatus. However, the present invention is not limited to this. For example, other images such as a printer, a facsimile machine, or a multifunction machine combining these functions may be used. Forming on an image forming apparatus and an image carrier using a transfer device as a transfer material carrier and a transfer material belt as a transfer material carrier, and sequentially transferring toner images of respective colors onto a transfer material such as a sheet carried on the transfer material belt The image forming apparatus may be configured to temporarily transfer and carry the toner image to the intermediate transfer member, and transfer the toner images carried on the intermediate transfer member to the transfer material in a lump. The same effect can be obtained by applying the present invention to this cleaning apparatus.
[0114]
【The invention's effect】
  As described above, according to the present invention, by vibrating the cleaning member by the vibration means,Image carrierSince the adhering material aggregated in the vicinity of the contact portion between the cleaning member and the cleaning member can be shaken off, it is possible to prevent a cleaning failure such that the adhering material slips through the cleaning member.
[0115]
  Furthermore,Image carrierBy selecting the operation of the vibration means according to the heating means, it is possible to efficiently operate the vibration means, and as a result, it is possible to extend the life of the vibration means.
[0116]
In particular, by efficiently removing aggregated deposits that are difficult to remove when the image forming apparatus is left for a long period of time, it is possible to more effectively prevent a cleaning failure such that the deposits pass through the cleaning member.
[0117]
In addition, according to the present invention, it is possible to effectively prevent an image defect such that the transfer material is contaminated due to a cleaning defect.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a schematic configuration of an image forming apparatus according to the present invention.
FIG. 2 is a longitudinal sectional view showing a schematic configuration of a cleaning device according to the present invention.
FIG. 3 is a configuration diagram of a heating unit of the photosensitive drum according to the present invention.
FIGS. 4A to 4D are enlarged views illustrating how toner aggregated in the vicinity of the edge of the cleaning blade is removed by vibration. FIGS.
FIG. 5 is a perspective view of a motor and a case constituting the vibration means.
FIG. 6 is a perspective view showing a state in which two vibration means are attached to the frame.
[Fig. 7]Reference exampleIt is the sequence after the front multiple rotation in.
[Fig. 8]Reference example3 is an operation sequence of the vibration means in interruption of the image forming operation in FIG.
FIG. 9Reference exampleIt is the sequence at the time of wire cleaning in.
FIG. 10First embodiment2 is a cross-sectional view of the fixing device in FIG.
FIG. 11First embodimentFIG. 6 is an operation sequence when the vibration means in FIG.
FIG.First embodimentFIG. 6 is an operation sequence when the vibration means in FIG.
FIG. 13Second embodimentIt is a flowchart which determines the frequency | count of the vibration means in.
FIG. 14 is an enlarged view showing how toner aggregates in the vicinity of the edge of a conventional cleaning blade.
[Explanation of symbols]
L ... center
P: Transfer material
1 ... Printer section
2 ... Reader part
11: Photosensitive drum
12 ... Primary charger
13 ... Exposure apparatus
13a ... Laser scanner
13b ... Reflection mirror
14 ... Developer
14a: Development sleeve
15 ... Transfer charger
16: Separating charger
17 ... Cleaning device
18a, 18b ... paper feed cassette
19a, 19b ... paper feed roller
20: Registration roller
21 ... Conveyor belt
22: Fixing device
22a: fixing roller
22a1 ... heating means
22b ... pressure roller
22b1 ... cored bar
22c ... temperature detection means
23 ... discharge roller
31 ... Platen glass
32: Document pressing plate
33 ... Light source
34a, 34b, 34c ... reflection mirror
35 ... Lens
36 ... CCD
37 Image processing unit
38 ... Electric signal
39 ... Automatic document feeder
41 ... Frame
41a ... contact surface
42 ... frame
43 ... Cleaning blade
43a ... Edge
44… Magnet roller
45 ... Conveying screw
46 ... sheet
47… Holder
47a ... contact surface
48, 49 ... Shaft
50 ... tension spring
51 ... Excitation means
52 ... Motor
52a ... Output shaft
53… Weight
54… Case
55 ... Control circuit
56 ... drum motor
71 ... Temperature detection means
72. Humidity detection means
81. Heating means
82 ... temperature detection means

Claims (1)

An image carrier, a transfer unit that transfers the toner image formed on the image carrier to a transfer material, a fixing unit that fixes the toner image to the transfer material, and a transfer residual toner that contacts the image carrier. In an image forming apparatus having a cleaning member to be removed and a vibration means for vibrating the cleaning member,
A heating unit that heats the image carrier when the power is turned off, a detection unit that detects the temperature of the fixing unit, and the number of vibration operations that are performed when the image carrier is stopped according to the detected temperature of the fixing unit. An image forming apparatus comprising a control unit for controlling, and performing the vibration operation a plurality of times when the detected temperature of the fixing unit is equal to or lower than a predetermined temperature.

Images