JP2007094075A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of surely collecting residual toner on a photoreceptor. <P>SOLUTION: An electrophotographic recording apparatus is configured to collect the residual toner 28a left on the photoreceptor 19 after a toner image formed on the rotating photoreceptor 19 is transferred to a medium. A first cleaning member is, for example, a brush member 22 for scraping the residual toner 28a while fitting to the surface of the photoreceptor 19. A second cleaning member is a cleaning blade 25, the second cleaning member is arranged on the downstream side of the first cleaning member in the rotating direction of the photoreceptor 19, and also, the second cleaning member is provided to scrape the residual toner 28a while coming in contact with the surface of the photoreceptor 19. A toner conveyance member 24 is arranged between the first cleaning member and the second cleaning member while leaving a space between the photoreceptor 19 and the toner conveyance member 24. The toner conveyance member 24 is provided to convey the residual toner 28a removed from the photoreceptor 19. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as an electrophotographic recording apparatus, and more particularly to an image forming apparatus that removes toner remaining on a photoreceptor after image transfer.

  In the conventional electrophotographic recording apparatus, the surface of the rotating photoreceptor is uniformly charged by the charging unit. Thereafter, an electrostatic latent image is formed on the charged surface by irradiating light according to the print data by the exposure unit. Next, the developing unit uses the electrostatic force to attach toner to the electrostatic latent image to form a toner image. The toner image is transferred to a medium by a transfer unit and then fixed by a fixing device. A cleaning member is provided on the downstream side of the transfer portion in the rotation direction of the photosensitive member. The developing unit is detachably provided in the image forming apparatus. Further, the developing unit may be detachably provided with an unused toner container.

  After transfer to the print medium, a small amount of toner remains attached to the photoreceptor. In order to scrape off the toner, a cleaning blade as a cleaning member is provided in contact with the photosensitive member. The toner scraped off by the cleaning blade is stored in a residual toner chamber provided below the cleaning blade.

JP 2000-259057 A

  In the above-described conventional cleaning apparatus, the toner scraped off by cleaning is stored in a toner chamber provided below, so that a relatively large storage chamber is required around the photosensitive member. Providing a large storage chamber in order to store residual toner that has not been used will hinder downsizing of the apparatus.

  An object of the present invention is to provide an electrophotographic recording apparatus that solves the above-described problems and can reliably collect residual toner on a photoreceptor.

In order to solve the above-described problems, the image forming apparatus of the present invention is configured to collect residual toner remaining on the photosensitive member after transferring the toner image formed on the rotating photosensitive member to a medium,
A first cleaning member that engages on the photoreceptor to wipe off residual toner;
A second cleaning member disposed on the downstream side of the first cleaning member with respect to the rotation direction of the photoconductor, and contacting the photoconductor to scrape residual toner;
The toner that is between the first cleaning member and the second cleaning member and is disposed with a gap between the photosensitive member and a toner conveying member that conveys residual toner removed from the photosensitive member. And a conveying member.

  The volume occupied by the cleaning device is reduced, and the device can be miniaturized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1
FIG. 1 shows an image forming apparatus according to the present invention. Image forming portions 40 a, 40 b, 40 c, and 40 d for forming yellow (Y), magenta (M), cyan (C), and black (K) images are respectively 1 along the transfer belt 5 a of the transfer unit 5. They are arranged in rows, and are arranged at a slightly higher position from the lower right in FIG. 1 toward the upper left. The image forming units 40a, 40b, 40c, and 40d include developing units 11a, 11b, 11c, and 11d and cleaning units 12a, 12b, 12c, and 12d, respectively. The developing rollers of the developing units 11a, 11b and 11c are in contact with the corresponding photoreceptors 19a, 19b, 19c and 19d. The cleaning units 12a, 12b, 12c, and 12d come into contact with the corresponding photoreceptors 19a, 19b, 19c, and 19d to collect residual toner.

  The medium tray 1 accommodates the medium 2. The separation roller 3a cooperates with the separation piece 3b and feeds the medium 2 to the transport rollers 4a and 4b while separating the medium 2 one by one. The transport rollers 4a and 4b transport the medium 2 and feed it to the transfer belt 5a. The transfer unit 5 includes a transfer belt 5a, a driving roller 5c, an idle roller 5b, and transfer rollers 20a, 20b, 20c and 20d. The transfer belt 5a is suspended from a drive roller 5c and an idle roller 5b. When the driving roller 5c rotates, the transfer belt 5a sequentially passes through the image forming unit in the direction of arrow A while placing the medium 2 thereon. The transfer rollers 20a, 20b, 20c, and 20d transfer the toner images from the photoconductors 19a, 19b, 19c, and 19d to the medium 2. The fixing unit 6 is a fixing unit that fixes the toner image transferred onto the medium 2, and includes a heating roller 6b, an idle roller 6c, and a fixing belt 6a suspended on the heating roller 6b and the idle roller 6c. The idle roller 6c and the pressure roller 6d sandwich the fixing belt 6a. The idle roller 6c may be heated with a heater. The discharge rollers 7a, 7b, 8a, and 8b discharge the medium 2 that has exited the fixing unit to the stacker 9.

  In FIG. 2, a cleaning brush 22, a toner conveying member 24, and a cleaning blade 25 are arranged along the circumferential surface of the photoconductor 19. The developing unit 11 includes a container 14, a toner storage container 13, a toner conveying member 15, and a developing roller 16. The toner conveying member 15 is a screw conveyor extending in the longitudinal direction, and transfers the toner from the center to the end of the developing unit. The developing roller 16 supplies the toner 28 to the photoconductor 19. The developing blade 17 forms a thin layer of toner 28 on the developing roller 16. The photoconductor 19 extends in a longitudinal direction (perpendicular to the paper surface) parallel to the rotation axis thereof, and in the direction of arrow B through a gear 19g (FIG. 4) provided at an end in the longitudinal direction. Driven by rotation. The transfer roller 21 is disposed so that the transfer belt 20 is sandwiched between the transfer roller 21 and the photoconductor 19. When the photoconductor 19 and the transfer roller 21 rotate in the directions of arrows B and C, respectively, and the transfer belt 5a runs in the direction of arrow D, the toner image is transferred from the photoconductor 19 to the medium 2 on the transfer belt. The

  The cleaning units 12a, 12b, 12c, and 12d come into contact with the corresponding photoreceptors 19a, 19b, 19c, and 19d to collect residual toner. The cleaning brush 22 is made of, for example, nylon, and the tip of the brush hair engages with the photoconductor. The cleaning brush 22 has a gear 22g (FIG. 4) provided at the end in the longitudinal direction, extending in the longitudinal direction (direction perpendicular to the paper surface) parallel to the rotation axis thereof. The gear 22g meshes with the gear 19g of the photoconductor 19. The toner conveying member 24 is made of, for example, coil-shaped stainless steel, and is disposed with a certain gap from the photoreceptor 19. The toner conveying member 24 has a gear 24g (FIG. 4) that extends in the longitudinal direction parallel to the rotation axis and is provided at an end in the longitudinal direction. The gear 24g meshes with the gear 22g of the cleaning brush 22. The cleaning blade 25 is made of an elastic material such as urethane, and an end portion thereof abuts on the photoconductor 19. The sheet metal member 25a (FIG. 2) supports the cleaning blade 25. The charging roller 27 rotates in contact with the surface of the photoconductor 19 to charge the surface of the photoconductor 19. The cover 26 surrounds the cleaning brush 22, the cleaning blade 25, the charging roller 27 and the toner conveying member 24, and forms an outer wall of the cleaning unit 12. The cover 26 has a rib 26 b (FIG. 8) that protrudes from the inner wall surface so as to hit the tip of the bristle of the cleaning brush 22. The rib 26 b extends in a direction parallel to the longitudinal direction of the cleaning brush 22.

FIG. 3 shows the cleaning unit according to the first embodiment. The cleaning brush 22, the cleaning blade 25, the toner conveying member 24, and the photoconductor 19 are arranged so as to satisfy the following conditions.
Lb ≦ 10mm
La ≦ 15mm
Lc ≦ 15mm
La + Lc ≦ 25mm
Here, a straight line connecting the point d and the point b on the line connecting the rotation center of the photosensitive member 19 and the rotation center of the toner conveying member 24 is Lb (that is, the shortest distance between the cleaning brush 22 and the photosensitive member 19). Distance), a straight line connecting the point c where the cleaning brush 22 is in contact with the photoconductor 19 and the point d is Lc, and the point a where the cleaning blade 25 is in contact with the photoconductor 19 and the point d are Let the connecting straight line be La.

  When the image forming apparatus receives a print command from an external device (not shown), in FIG. 1, the separation roller 3a cooperates with the separation piece 3b to separate the medium 2 one by one, and to the conveyance rollers 4a and 4b. Feed paper. The conveyance rollers 4 a and 4 b convey the medium 2 to the transfer belt 5. It is placed on the transfer belt and passes through each image forming unit. At this time, the exposure light 18 irradiates the surfaces of the photoconductors 19a, 19b, 19c, and 19d according to the print data to form an electrostatic latent image. The potential of the exposed part drops to around 0V.

  On the other hand, in the developing unit 11, the toner conveying member 15 is rotated in the direction of arrow E by a driving source (not shown) to supply toner onto the developing roller 16. The toner on the developing roller 16 is formed into a thin layer by the developing blade 17 and is charged. Since the photoconductor 19 continues to rotate, the thinned toner on the developing roller 16 is adsorbed to the exposed portion of the photoconductor 19 by electrostatic force, and as a result, the electrostatic latent image is developed with the toner and the toner image It becomes.

  This toner image is transferred by the transfer roller 21 from the direction of arrow D onto the medium conveyed by the transfer belt 20. Thereafter, the medium 2 is conveyed to the fixing unit 6 and the toner image is fixed in the fixing unit. The medium 2 is left in the stacker 9 provided outside the image forming apparatus by the discharge rollers 7a, 7b, 8c and 8b.

  FIG. 4 is a perspective view showing the positional relationship between the cleaning brush 22 and the toner conveying member 24. A small amount of toner remains on the photoreceptor 19 after the toner image is transferred. The cleaning brush 22 is rotated in the direction of the arrow G (FIG. 2) via the gear 22g to wipe off the residual toner on the photoconductor 19. The peripheral speed of the cleaning brush 22 is equal to or higher than the peripheral speed of the photoconductor 19. Further, the cleaning blade 25 comes into pressure contact with the surface of the photoreceptor 19 and scrapes the remaining residual toner. The toner conveying member 24 is driven to rotate in the direction of arrow H (FIG. 2) via the gear 24g, and the residual toner removed from the photoconductor 19 is conveyed in the direction of arrow I and discharged from the discharge port.

FIG. 5 is a detailed view of the cleaning unit 12. Residual toner 28 a on the photoreceptor is removed by the cleaning brush 22 and the cleaning blade 25. The removed residual toner 28a is accumulated between the toner conveying member 24 and the cleaning blade 25. When the toner conveying member 24 rotates in the direction of the arrow H, a part of the residual toner 28a moves onto the rib 26a protruding inward of the cover 26, and becomes a collected toner 28b and is discharged from the discharge port. That is, the residual toner 28a is accumulated between the toner conveying member 24 and the cleaning blade 25 and is conveyed by the toner conveying member 24 so as not to increase further.

  Table 1 shows the transport performance of the collected toner 28b using Lb as a parameter. The evaluation was performed at a drum duty of 30,000 with a printing duty of 5%. ○ indicates good. A cross indicates that the toner is clogged, causes a cleaning failure, and the printing is smudged (no limitation on environmental conditions). The Δ mark indicates that the toner is clogged in a high temperature and high humidity environment (28 ° C., 80%), causing a cleaning failure, and smearing occurs in printing. From Table 1, if the value of Lb is 10 mm or less, good toner conveyance performance can be obtained regardless of the environmental conditions in which the cleaning unit operates, and no smearing occurs during printing.

  Table 2 shows the transport performance of the collected toner 28b with La and Lc as parameters. From Table 2, if Lb ≦ 10 mm, La ≦ 15 mm, Lc ≦ 15 mm, and La + Lc ≦ 25 mm are satisfied, good toner conveyance performance can be obtained regardless of environmental conditions, and smearing during printing does not occur. Further, the occupation volume of the cleaning device is reduced, and the image forming apparatus can be downsized. Since the polymer toner has a small particle size, high cleaning performance is required. Therefore, if the present invention is applied to an apparatus using polymerized toner, high cleaning performance can be realized.

Embodiment 2
FIG. 6 is a side view showing the cleaning unit and the developing unit according to the second embodiment. The toner conveying member 24 and the lubricant installation place 26c are arranged around the cleaning brush 22, and the lubricant installation place 26c is provided on the downstream side of the toner conveying member 24 in the rotation direction of the arrow G of the cleaning brush 22. . A solid lubricant 31 and an elastic member 30 are accommodated inside the lubricant installation place 26 c, and the elastic member 30 biases the lubricant 31 toward the tip of the bristle of the cleaning brush 22. As the lubricant 31, for example, a lubricant obtained by melting a lubricant additive mainly composed of zinc stearate and then cooling and solidifying it is used. Since the other configuration of the second embodiment is the same as that of the first embodiment, description thereof is omitted.

  FIG. 7 shows a main part of the cleaning unit according to the second embodiment. As shown in FIG. 7, the minute particles 31a of the lubricant 31 adhere to the tip of the brush bristles of the cleaning brush 22, and the cleaning brush 22 sensitizes the minute particles 31a by a certain amount upstream of the contact portion c. The toner is supplied onto the body 19, and the residual toner 28 a is peeled from the photoreceptor 19 on the downstream side. The lubricant 31 adhering to the photoconductor 19 is not completely scraped off by the cleaning blade 25, and the lubricant 31 of the minute particles 31 a of the lubricant 31 continues to adhere to the photoconductor 19. Other operations in the embodiment are the same as those in the first embodiment, and the description thereof is omitted.

  By supplying the minute particles 31 a of the lubricant 31 onto the photoconductor 19, friction on the surface of the photoconductor 19 is reduced, and residual toner on the photoconductor 19 can be easily removed. Further, the lubricant 31 is provided on the downstream side of the toner conveying member 24 with respect to the arrow G. Therefore, after the removed residual toner 28 a is pushed out toward the toner conveying member 24 by the cleaning brush 22, the lubricant 31 adheres to the tip of the bristle of the cleaning brush 22. For this reason, the removed toner 28a does not stay at the place where the lubricant 31 is installed. Therefore, it is easy to supply the lubricant 31 to the surface of the photoreceptor 19. Further, since the residual toner tends to adhere to the portion of the cleaning brush 22 close to the surface of the photoconductor 19, the lubricant 31 is attached to the cleaning brush 22 at a position far from the surface of the photoconductor of the cleaning brush 22. I did it. Thereby, the lubricant 31 can be stably supplied onto the photoreceptor 19. Other effects of the second embodiment are the same as those of the first embodiment, and a description thereof will be omitted.

Embodiment 3
FIG. 8 is a side view showing the cleaning unit and the developing unit according to the third embodiment. In FIG. 8, the flicker 26 b is provided on the downstream side of the portion where the cleaning brush 22 engages with the photoconductor 19 with respect to the rotation direction of the cleaning brush 22. The flicker 26 b is provided in a part of the cover 26, extends in a direction substantially parallel to the rotation axis of the cleaning brush 22, and has the same length as or longer than the cleaning brush 22. The flicker 26b is slightly inserted so as to be able to engage with the bristle when the cleaning brush 22 is rotated. As the cleaning brush 22 rotates, it strikes the tip of the bristles, deflecting and releasing the bristles. As a result, the bristles vibrate and the attached toner particles are wiped off. Other configurations are the same as those in the first embodiment, and thus description thereof is omitted.

  FIG. 9 shows a main part of the cleaning unit according to the third embodiment. As shown in FIG. 9, the cleaning brush 22 engages with the surface of the photoconductor 19 to wipe off the residual toner 28 a on the photoconductor 19. Further, since the flicker 26b engages in the vicinity of the tip of the bristle of the cleaning brush 22, even if the toner removed from the photoconductor 19 adheres to the tip of the bristle or enters between the bristle and the bristle, the toner is removed. be able to. Therefore, the toner does not clog or remain fixed between the brush bristles of the cleaning brush 22, and the residual toner 28 a adhering to the surface of the photoreceptor 19 is not wiped off and the performance is not deteriorated. Other operations and effects are the same as those in the first embodiment.

  FIG. 10 shows a main part of a modification of the third embodiment. In this modification, the structure of the third embodiment is combined with the lubricant installation place 26 c of the second embodiment, the solid lubricant 31, and the elastic member 30. Since other operations and effects are the same as those in the third and second embodiments, detailed description thereof is omitted.

  The present invention can be applied to an image forming apparatus used for a copying machine, an LED printer, a laser beam printer, a facsimile, an MFP, and the like.

1 shows an image forming apparatus according to the present invention. 2 shows a positional relationship among the cleaning brush, the toner conveying member, and the cleaning blade according to the first embodiment. The main part of a cleaning unit is shown. FIG. 6 is a perspective view showing a positional relationship between a cleaning brush and a toner conveying member. 3 is a detailed view of the cleaning unit 12. FIG. 6 is a side view showing a cleaning unit and a developing unit according to Embodiment 2. FIG. The principal part of the cleaning unit which concerns on Embodiment 2 is shown. 10 is a side view showing a cleaning unit and a developing unit according to Embodiment 3. FIG. The principal part of the cleaning unit which concerns on Embodiment 3 is shown. The principal part of the modification of Embodiment 3 is shown.

Explanation of symbols

  19 Photoconductor, 22 Cleaning brush, 24 Recovery roller, 25 Cleaning blade, 31 Lubricant, 26b Rib.

Claims (5)

In an image forming apparatus for recovering residual toner remaining on the photosensitive member after transferring the toner image formed on the rotating photosensitive member to a medium,
A first cleaning member for recovering residual toner facing the photoreceptor;
A second cleaning member disposed on the downstream side of the first cleaning member in the rotational direction of the photoconductor, and contacting the photoconductor to scrape residual toner;
A toner conveying member positioned between the first cleaning member and the second cleaning member and provided with a gap between the photosensitive member and carrying the residual toner removed from the photosensitive member; An image forming apparatus comprising: a toner conveying member. The first cleaning member has a rotation axis parallel to the rotation axis of the photosensitive member. When the first cleaning member rotates, the outer peripheral portion of the first cleaning member engages with the photosensitive member and remains. Toner off,
The image forming apparatus according to claim 1, wherein the second cleaning member extends in a direction parallel to the rotation axis of the photosensitive member, and scrapes off toner remaining on the surface of the photosensitive member.   The first cleaning member is a brush having brush bristles, and when the first cleaning member rotates, an engagement portion that engages with the bristles and removes residual toner attached to the bristles is further provided. The image forming apparatus according to claim 2. The first cleaning member, the second cleaning member, and the toner conveying member are disposed so as to satisfy the following relationship:
Lb ≦ 10mm
La ≦ 15mm
Lc ≦ 15mm
La + Lc ≦ 25mm
Here, Lb is a point d on the surface of the toner conveying member that intersects a straight line connecting the rotation center of the photosensitive member and the rotation center of the toner conveying member, and a point b on the surface of the photosensitive member that intersects the straight line. La is a straight line connecting point c where the first cleaning member contacts the photoconductor and the point d, and La is a point a where the second cleaning member contacts the photoconductor. The image forming apparatus according to claim 2, wherein the image forming apparatus is a straight line connecting the point d.   The image forming apparatus according to claim 3, further comprising a solid lubricant disposed so as to be engaged with a front end portion of the brush bristles.

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