JP3706328B2 - Residual toner recovery device for image forming machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention removes residual toner adhering to the peripheral surface of a toner image forming body such as a photosensitive member and an intermediate transfer member in an image forming machine such as a printer, a copying machine, and a facsimile, and collects the removed residual toner. The present invention relates to a residual toner collecting device.
[0002]
[Prior art]
In image forming machines such as printers, copiers, and facsimiles, a cleaning mechanism that removes residual toner adhering to the peripheral surface of a toner image forming body such as a photosensitive member or an intermediate transfer member, and the cleaning mechanism removes the residual toner. A residual toner collecting device including a residual toner collecting container for containing the residual toner and a residual toner carrying mechanism for carrying the residual toner removed by the cleaning mechanism to the residual toner collecting container is provided. The residual toner transport mechanism is disposed in the transport path, a residual toner dropping path for dropping the residual toner removed by the cleaning mechanism, a transport path connecting the residual toner drop path and the residual toner collection container, and the transport path. It comprises a conveying screw having spiral blades formed on the peripheral surface of the rotating shaft, and the residual toner dropped through the residual toner dropping passage is conveyed to the residual toner collecting container along the conveying path by the conveying action of the conveying screw. It is like that.
[0003]
However, when the residual toner transported by the transport screw of the residual toner transport mechanism is significantly reduced in fluidity due to paper dust mixing, temperature, humidity, or the like, it adheres to the lower part of the residual toner dropping passage and accumulates. Aggregation causes toner clogging in the residual toner conveyance mechanism. In addition, when the residual toner fluidity is significantly reduced as described above, the residual toner adheres to the side surface of the spiral blade of the conveying screw, the conveying force of the conveying screw is reduced, and toner clogging occurs in the residual toner conveying mechanism. Cause. Thus, when toner clogging occurs in the residual toner transport mechanism, there is a problem that the load on the drive system of the image forming machine increases and the inside of the machine is contaminated.
[0004]
In order to prevent the residual toner from adhering to the lower portion of the residual toner dropping path described above, a sphere having a diameter larger than the pitch of the spiral blades of the conveying screw is placed in contact with the conveying screw in the conveying residual toner falling path. The provided technology is disclosed in Japanese Patent Laid-Open No. 7-92875.
[0005]
[Problems to be solved by the invention]
Thus, the technique described in the above publication prevents the toner from accumulating in the residual toner dropping passage, and the toner attached to the spiral blade of the conveying screw may be broken by vibration. The toner adhering to the toner cannot be positively removed, and it is impossible to prevent the toner adhering to the spiral blade from being deposited.
[0006]
The present invention has been made in view of the above facts, and the main technical problem thereof is that residual toner removed from the peripheral surface of the toner image forming body by a cleaning mechanism and conveyed to a residual toner collecting container by a conveying screw. Another object of the present invention is to provide a residual toner recovery device for an image forming machine, which is prevented from adhering to and depositing on a spiral blade of a conveying screw.
[0007]
[Means for Solving the Problems]
In order to solve the main technical problem, according to the present invention, a cleaning mechanism that removes residual toner adhering to the peripheral surface of a toner image forming body, and a residual that contains residual toner removed by the cleaning mechanism are provided. In a residual toner recovery device of an image forming machine, comprising: a toner recovery container; and a residual toner transport mechanism that transports residual toner removed by the cleaning mechanism to the residual toner recovery container;
The residual toner transport mechanism includes a residual toner dropping path for dropping the residual toner removed by the cleaning mechanism, a transport path connecting the residual toner falling path and the residual toner collection container, and a transport path disposed in the transport path. And a conveying screw having a spiral blade formed on the peripheral surface of the rotating shaft, and a sphere disposed on the conveying screw facing the residual toner dropping passage,
The relationship between the diameter (D) of the sphere and the pitch (p) of the spiral blade is set to p>D> 0.8P , and the relationship between the diameter (D) of the sphere and the height (h) of the spiral blade The relationship is set to h <1 / 2D,
A residual toner recovery device for an image forming machine is provided.
[0008]
The relationship between the diameter (D) of the sphere and the pitch (p) of the spiral blade is preferably set to p>D> 0.8P, and the specific gravity of the sphere is greater than the specific gravity of the residual toner. It is desirable to set it large.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of a residual toner recovery device for an image forming machine constructed according to the present invention will be described below with reference to the accompanying drawings.
[0010]
FIG. 1 shows a schematic cross-sectional view of a laser beam printer as an image forming machine equipped with a residual toner collecting apparatus constructed according to the present invention.
The illustrated laser beam printer includes a rectangular parallelepiped housing 2 made of synthetic resin. In the substantially central portion of the housing 2, there is a space between a front side plate and a rear side plate made of a metal plate (not shown) arranged in the housing 2 at a predetermined interval in the front-rear direction (direction perpendicular to the paper surface in FIG. 1). A photosensitive drum 3 as a toner image forming member is rotatably disposed. The photosensitive drum 3 is driven to rotate by sequentially passing through a charging area, an electrostatic latent image forming area, a developing area, an image transfer area, and a cleaning area in a direction indicated by an arrow by a gear transmission (not shown). Around the photosensitive drum 3, a charging corona discharge device 4 is provided in a charging area, a developing device 5 is provided in a developing area, an intermediate transfer body 6 as a toner image forming body is provided in an image transferring area, and a photosensitive drum is provided in a cleaning area. Each of the cleaning mechanisms 7 is provided. In the illustrated embodiment, the developing device 5 includes a yellow toner developing unit 5a, a magenta toner developing unit 5b, a cyan toner developing unit 5c, and a black toner developing unit 5d. Further, the intermediate transfer member 6 is connected to the front and rear side plates disposed at a predetermined interval in the front-rear direction (direction perpendicular to the paper surface in FIG. 1) in the housing 2 in the same manner as the photosensitive drum 3. It is rotatably arranged between them and is driven to rotate in the direction indicated by the arrow by a gear transmission (not shown). A cleaning mechanism 8 for the intermediate transfer member is disposed at the lower left portion of the intermediate transfer member 6 in FIG. The cleaning mechanism 7 and the cleaning mechanism 8 may have a known configuration, and include a cleaning fur brush, a cleaning blade, and a conveying screw in cleaning cases 71 and 81, respectively.
[0011]
A laser unit 9 serving as an electrostatic latent image forming unit is disposed in the upper part of the housing 2. The laser unit 9 projects laser light based on image information output from a computer, for example, onto the peripheral surface of the photosensitive drum 3 in an electrostatic latent image forming area between the charging area and the developing area. In addition, a secondary transfer roller 10 is disposed below the intermediate transfer body 6 in the lower part of the housing 2, and is conveyed downstream of the secondary transfer roller 10 (left side in FIG. 1). A belt mechanism 11 and a fixing unit 12 are provided.
[0012]
Next, the operation of the laser beam printer described above will be briefly described.
While the photosensitive drum 3 is rotated in the direction indicated by the arrow, the charging corona discharger 4 charges the photosensitive layer of the photosensitive drum 3 to a specific polarity. Next, laser light is projected onto the photosensitive drum 3 from the laser unit 9 in the electrostatic latent image forming area between the charging area where the charging corona discharger 4 is disposed and the developing area where the developing device 5 is disposed. Then, an electrostatic latent image corresponding to the image information is formed on the peripheral surface of the photosensitive drum 3. Thereafter, the developing device 5 causes toner to act on the electrostatic latent image on the photosensitive drum 3 to visualize the electrostatic latent image. The toner image formed on the photosensitive drum 3 in this way is transferred to an intermediate transfer member 6 as a toner image forming member. In the case of color printing, the photosensitive drum 3 is charged by the corona discharger 4 for charging for each color, the exposure by the laser unit 9, the developing unit 5a for yellow toner, the developing unit 5b for magenta toner, and the developing unit for cyan toner. Development is performed by the developing unit 5d and the black toner developing unit 5d, and is transferred to the intermediate transfer member 6 each time. As a result, a multicolor toner image corresponding to the image signal for one sheet is transferred to the intermediate transfer body 6.
[0013]
On the other hand, the sheet P fed from a sheet feeding device (not shown) is temporarily stopped by a pair of registration rollers (not shown), and the intermediate transfer member 6 is timed with the intermediate transfer member 6 to which the toner image is transferred as described above. And the secondary transfer roller 10 are conveyed to a secondary transfer area facing each other. A toner image formed on the peripheral surface of the intermediate transfer member 6 by the action of the transfer roller 10 is transferred to the surface of the paper P conveyed to the secondary transfer area. The sheet P on which the toner image has been transferred is peeled off from the intermediate transfer member 6 and conveyed to the fixing unit 12 by the conveying belt mechanism 11, where the toner image is heated and fixed on the surface of the sheet and then discharged out of the housing 2. Is done.
[0014]
The residual toner adhering to the surface of the photosensitive drum 3 after the toner image is transferred from the photosensitive drum 3 to the intermediate transfer body 6 as described above is removed by the cleaning mechanism 7. On the other hand, residual toner adhering to the surface of the intermediate transfer body 6 after the toner image is transferred from the intermediate transfer body 6 to the paper P is removed by the cleaning mechanism 8. Hereinafter, a residual toner collecting device removed by the cleaning mechanism 7 and the cleaning mechanism 8 will be described with reference to FIGS. 1 and 2.
[0015]
The residual toner recovery device 20 in the illustrated embodiment includes a residual toner recovery container 21 for storing residual toner removed by the cleaning mechanism 7 and the cleaning mechanism 8, and residual toner removed by the cleaning mechanism 7 and the cleaning mechanism 8. A residual toner transport mechanism 30 for transporting the toner to the toner recovery container 21 is provided. The residual toner collection container 21 is formed of an appropriate synthetic resin, and a joint portion 212 including a residual toner introduction port 211 is provided on the upper portion thereof. This joint portion 202 is connected to a connection portion, which will be described later, of the residual toner transport mechanism 30.
[0016]
The residual toner transport mechanism 30 includes a casing 31 including a transport path 310 extending in a direction perpendicular to the axial direction of the cleaning mechanism 7 and the cleaning mechanism 8 below the cleaning mechanism 7 and the cleaning mechanism 8. The casing 31 includes a first casing member 32 and a second casing member 33 that are formed of an appropriate synthetic resin.
[0017]
The first casing member 32 includes a receiving portion 321 that fits the inner portion of the cleaning case 81 of the cleaning mechanism 8 on the upper side in FIG. The receiving portion 321 is formed with a residual toner dropping passage 322 that communicates the toner discharge port 811 formed in the inner portion of the cleaning case 81 and the conveyance passage 310. On the other hand, the second casing member 33 includes a connecting portion 331 that is connected to the rear portion of the cleaning case 71 of the cleaning mechanism 7 on the upper side in FIG. The connecting portion 331 is formed with a residual toner dropping passage 332 that communicates a toner discharge port (not shown) formed in the inner portion of the cleaning case 71 with the conveyance passage 310.
Further, the second casing member 33 includes a connection portion 333 that connects to the residual toner collecting container 20 on the lower side in FIG. 2 on the connection side with the first casing member 32. The connecting portion 333 is formed with a residual toner discharge port 334 that communicates with the conveyance path 310 between the residual toner dropping passages 322 and 332.
[0018]
A conveyance path 34 formed by the first casing member 32 and the second casing member 33 is provided with a conveyance screw 34 formed of an appropriate synthetic resin. The conveying screw 34 includes a rotation shaft 341 and a first spiral blade 342 and a second spiral blade 343 formed on the peripheral surface of the rotation shaft 341. A support portion 345 having a non-circular connecting hole 344 is provided at one end portion (left end portion in FIG. 2) of the rotation shaft 341, and the support bush 345 is mounted on the first casing member 32. 35 is rotatably supported.
On the other hand, the other end portion (right end portion in FIG. 2) of the rotating shaft 341 is rotatably supported by a bearing bush 36 attached to the second casing member 33. In addition, a snap ring 37 for retaining is attached to the right side of the bearing bush 36 of the rotating shaft 341 in FIG.
[0019]
The first spiral blade 342 and the second spiral blade 343 formed on the peripheral surface of the rotating shaft 341 are formed so that the spiral winding directions are opposite to each other. The first spiral blade 342 is formed from the left end portion of the rotating shaft 341 in FIG. 2 to a position reaching the substantially central portion of the residual toner discharge port 334, and the second spiral blade 343 is illustrated in FIG. 2 of the rotating shaft 341. It is formed from the right end portion to a position reaching the substantially central portion of the residual toner discharge port 334. The conveying screw 34 configured in this manner is connected to a connecting hole 344 formed in a support portion 345 provided at one end of the rotating shaft 341 by connecting a driving shaft of a driving mechanism (not shown) with an arrow in FIG. It is driven to rotate in the direction shown. The first spiral blade 342 constituting the conveying screw 34 rotating in the direction indicated by the arrow moves the residual toner that has fallen into the conveying path 310 from the toner discharge port 811 of the cleaning mechanism 8 through the residual toner dropping path 322 in FIG. In other words, the toner is conveyed toward the residual toner discharge port 334. On the other hand, the second spiral blade 343 causes the residual toner that has fallen from the toner discharge port (not shown) of the cleaning mechanism 7 to the conveyance path 310 through the residual toner drop passage 332 toward the left side, that is, the residual toner discharge port 334 in FIG. Transport. As described above, the residual toner dropped into the conveyance path 310 through the residual toner dropping passages 322 and 332 is left as a residual toner discharge port 334 by the first spiral blade 342 and the second spiral blade 343 constituting the conveyance screw 34, respectively. And is discharged from the residual toner discharge port 334 to the residual toner collection container 20.
[0020]
On the conveying screw 34 facing the residual toner dropping passages 322 and 332, spheres 37 and 38 are disposed, respectively. The spheres 37 and 38 are configured such that the diameter (D) is smaller (p> D) than the pitch (p) of the first spiral blade 342 and the second spiral blade 343 of the conveying screw 34, and the radius (1). / 2D) is larger than the height (h) of the first spiral blade 342 and the second spiral blade 343 of the conveying screw 34 (h <1 / 2D). In the spheres 37 and 38, the relationship between the diameter (D) and the pitch (p) of the first spiral blade 342 and the second spiral blade 343 is set to p>D> 0.8P as described later. It is desirable to do. Furthermore, it is desirable that the specific gravity of the spheres 37 and 38 is larger than the specific gravity (1-2) of the residual toner, and steel, brass, aluminum alloy, synthetic resin, or the like can be used.
[0021]
The residual toner collecting device 20 in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
Since the diameters (D) of the spheres 37 and 38 are smaller than the pitch (p) of the first spiral blade 342 and the second spiral blade 343 of the conveying screw 34 (p> D), the first spiral It can be positioned between the blades of the blade 342 and the second spiral blade 343. In this state, when the conveying screw 34 is driven to rotate in the direction indicated by the arrow in FIG. 2, the spheres 37 and 38 together with the residual toner dropped into the conveying path 310 through the residual toner dropping passages 322 and 332 are residual toner discharge ports 334. In this case, the toner moves while scraping off residual toner adhering between the blades due to friction with the first spiral blade 342 and the second spiral blade 343. When the spheres 37 and 38 reach the wall surfaces 322a and 332a of the residual toner dropping passages 322 and 332 on the residual toner discharge port 334 side, the movement to the residual toner discharge port 334 side is restricted. However, since the conveying screw 34 continues to rotate, the spheres 37 and 38 temporarily escape upward along the wall surfaces 322a and 332a as shown by a two-dot chain line in FIG. In FIG. 2, it rolls back to the vicinity of the movement start position indicated by the solid line. When the spherical bodies 37 and 38 repeatedly perform this reciprocating motion, the residual toner attached between the first spiral blade 342 and the second spiral blade 343 is scraped off, and the residual toner is accumulated between the blades. Can be prevented.
[0022]
Here, the relationship between the diameters (D) of the spheres 37 and 38 and the pitch (p) and height (h) of the first spiral blade 342 and the second spiral blade 343 of the conveying screw 34 will be examined.
If the diameters (D) of the spheres 37 and 38 are smaller than the pitch (p) of the first spiral blade 342 and the second spiral blade 343, there is an action of scraping the residual toner to the root of the blade, Since the moving distance over the blades becomes long, the reciprocating motion of the sphere is not smoothly performed. Therefore, the relationship between the diameter (D) of the spheres 37 and 38 and the pitch (p) of the first spiral blade 342 and the second spiral blade 343 is preferably set to p>D> 0.8P.
When the height (h) of the first spiral blade 342 and the second spiral blade 343 is larger than the radius (1 / 2D) of the spheres 37 and 38, the action of scraping the residual toner to the root of the blade is However, when the spheres 37 and 38 get over the blades, the resistance force of the wall surfaces 322a and 332a acts above the center of the sphere in the horizontal direction. It becomes. Therefore, the relationship between the radii (1 / 2D) of the spheres 37 and 38 and the height (h) of the first spiral blade 342 and the second spiral blade 343 is preferably set to h <1 / 2D.
In order to smoothly perform the reciprocating motion of the spheres 37 and 38, the angle α with the axes of the first spiral blade 342 and the second spiral blade 343 also affects. The larger the angle α, the smoother the movement of the spherical blades is, but the larger the angle α, the lower the toner conveying force. Therefore, it is desirable that the angle α is appropriately set in consideration of the toner conveyance force and the smoothness of the reciprocating motion of the sphere.
[0023]
【Example】
Considering the above-mentioned matters, the diameter of the rotary shaft 341 is 10 mm, the pitch (p) of the first spiral blade 342 and the second spiral blade 343 is 10 mm, the height (h) is 2.5 mm, the blade and the shaft Was produced using a steel ball having a diameter (D) of 9.5 mm as the spheres 37 and 38, and the above reciprocating motion of the sphere was smoothly performed. Residual toner did not accumulate on the first spiral blade 342 and the second spiral blade 343.
[0024]
As described above, the residual toner collecting device configured according to the present invention has been described based on the embodiment applied to the color laser beam printer including the intermediate transfer member. However, the present invention is not limited to the embodiment, and the copying is performed. The present invention can be applied to various image forming machines such as a printer and a facsimile.
[0025]
【The invention's effect】
In the residual toner collecting device of the image forming machine according to the present invention, the relationship between the pitch (p) and height (h) of the helical screw and the spherical diameter (D) of the conveying screw constituting the residual toner conveying mechanism is p> Since D> 0.8P and h <1 / 2D are set, since the sphere is positioned between the blades, the residual toner adhered between the blades due to friction with the spiral blades can be scraped off. Therefore, it is possible to prevent problems caused by the accumulation of residual toner on the spiral blade of the conveying screw.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a laser beam printer as an image forming machine equipped with a residual toner collecting device constructed according to the present invention.
FIG. 2 is a cross-sectional view of a main part of a residual toner recovery device configured according to the present invention.
[Explanation of symbols]
2: Image forming machine housing 3: Photoconductor drum 4: Charging corona discharger 5: Developing device 5a: Yellow toner developing unit 5b: Magenta developing unit 5c: Cyan toner developing unit 5d: Black toner developing Unit 6: Intermediate transfer member 7: Cleaning mechanism for photosensitive drum 8: Cleaning mechanism for intermediate transfer member 9: Laser unit 10: Secondary transfer roller 11: Conveying belt mechanism 12: Fixing unit 20: Residual toner collecting device 21 : Residual toner collecting container 30: Residual toner transport mechanism 31: Casing 310: Transport path 32: First casing member 33: Second casing member 321: Receiving part 322: Residual toner dropping path 331: Connecting part 332: Residual toner Drop passage 333: Connection portion 334: Residual toner discharge port 34: Conveying screw 341: Rotating shaft 42: The first spiral blade 343: second spiral blade 35, 36: bearing bushes 37 and 38: spheres

Claims (1)

A cleaning mechanism that removes residual toner adhering to the peripheral surface of the toner image forming body, a residual toner collection container that stores residual toner removed by the cleaning mechanism, and residual toner removed by the cleaning mechanism In a residual toner recovery device of an image forming machine comprising a residual toner transport mechanism for transporting to a residual toner recovery container,
The residual toner transport mechanism includes a residual toner dropping path for dropping the residual toner removed by the cleaning mechanism, a transport path connecting the residual toner falling path and the residual toner collection container, and a transport path disposed in the transport path. And a conveying screw having a spiral blade formed on the peripheral surface of the rotating shaft, and a sphere disposed on the conveying screw facing the residual toner dropping passage,
The relationship between the diameter (D) of the sphere and the pitch (p) of the spiral blade is set to p>D> 0.8P , and the relationship between the diameter (D) of the sphere and the height (h) of the spiral blade The relationship is set to h <1 / 2D,
A residual toner recovery device for an image forming machine.

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