JP5084361B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile machine, or a combination machine thereof, and in particular, automatically fills an empty developing unit with a new developer during installation or maintenance. The present invention relates to an image forming apparatus.

Conventionally, in an image forming apparatus such as a copying machine or a printer, an empty developing unit (developing apparatus) is supplied with toner and a carrier at the time of delivery (when the image forming apparatus is installed) or when a developer is replaced (at the time of maintenance). There is known a technique of filling a two-component developer (including cases where additives and the like are added) (see, for example, Patent Document 1).
Specifically, at the time of delivery, the two-component developer is filled (supplied) into the empty developing unit immediately before the initial setting and operation check of the image forming apparatus at the user installation location. In addition, when the developer is replaced, an existing developer (developer that has reached the end of its life) is taken out from the developing unit, and then a new developer is filled in the empty developing unit.

On the other hand, Patent Document 2 discloses a technique for operating a handle for manually driving the developing unit when the developing unit is filled with developer. That is, the developer is filled with the developer while manually turning the handle.
Japanese Patent Application Laid-Open No. H10-260260 discloses a technique for storing a developer in advance in a developing unit (developing device) installed in an image forming apparatus. Further, in Patent Document 3 and the like, a movable shutter is provided at the opening of the developing unit facing the image carrier, and when the use of the developing unit is started, the shutter is opened so that the developing process can be performed. ing.

Japanese Patent No. 35457779 JP-A-6-19324 JP 2006-84892 A

  In the conventional image forming apparatus described above, it is difficult to fill the developing portion with the developer with a simple configuration and operation without causing problems such as turning over of the cleaning blade.

Specifically, the technique disclosed in Patent Document 2 and the like is insufficient in workability because the handle must be manually operated to fill the developing portion with the developer. In particular, in the case of a large-sized apparatus and a large amount of developer filled in the developing unit, a large force is required to operate the handle, which is a problem that cannot be ignored.
Moreover, since the technique of patent document 3 etc. are provided with the shutter in the opening part of the image development part, it is based on the developer accommodated in the image development part beforehand (it is the developer carry | supported by the developer carrier). It can be expected that the defect that the surface of the image carrier is scratched is suppressed. However, since it is necessary to manually fill the developer when changing the developer, workability is insufficient. Further, since the movable shutter is provided in the developing unit, the configuration of the developing unit is complicated, and the distance between the image carrier and the developer carrier is limited.

  In order to solve such problems, during installation and maintenance, a developer container for filling is set in the image forming apparatus, and the drive unit of the image forming apparatus (image carrier, developing unit) is operated, It is conceivable to automatically fill the empty developing part with the developer. However, in that case, if you forget to remove the cap (or seal) installed in the opening of the developer container, the developer is not correctly charged in the developing unit even if the developer charging is started. Since the image carrier is driven for a long time without any toner being supplied to it, a cleaning blade that contacts the image carrier (to remove deposits such as untransferred toner adhering to the image carrier) In other words, there is a problem that the cleaning blade is turned over without sufficiently supplying toner to the edge portion. When the cleaning blade is turned over, secondary problems such as defective cleaning and abnormal noise occur.

  The present invention has been made to solve the above-described problems, and allows the developer to be filled in the developing section with a relatively simple configuration and operation without causing problems such as turning over of the cleaning blade. Another object is to provide an image forming apparatus.

  According to a first aspect of the present invention, an image forming apparatus includes an image carrier, a developing unit that develops a latent image formed on the image carrier, and a developing unit that drives the developing unit. A developer filling means for filling the developer, wherein the developing section includes a developer carrier that faces the image carrier and carries the developer, and is in a state where the developer is not accommodated. When the developer is newly filled with the developer, the developer is started to be driven and the developer is charged on the developer carrier even after a predetermined time has elapsed since the developer filling means started. When the developer is not carried, the driving of the developing unit and the image carrier is stopped.

  According to a second aspect of the present invention, there is provided an image forming apparatus according to the first aspect of the present invention, further comprising a toner concentration detecting means for detecting a toner concentration of the developer accommodated in the developing section. When a new developer is charged into the developing unit that is not accommodated, the driving of the developing unit is started and the developer charging unit starts charging the developer and a predetermined time has elapsed. When the detection result of the toner density detection means does not reach a predetermined value, the driving of the developing unit and the image carrier is stopped.

  According to a third aspect of the present invention, there is provided an image forming apparatus according to the first aspect of the present invention, further comprising torque detecting means for detecting a driving torque of the developing unit, wherein the developer is not accommodated. When the developer is newly filled with the developer, the detection result of the torque detector is started even when a predetermined time has elapsed after the developer is started to be driven and the developer is charged with the developer. When the value does not reach a predetermined value, the driving of the developing unit and the image carrier is stopped.

  According to a fourth aspect of the present invention, there is provided an image forming apparatus according to the first aspect of the present invention, further comprising an image density detecting means for detecting an image density of the toner image formed on the image carrier, and developing the image. When a new developer is filled in the developing unit in a state where no developer is accommodated, the driving of the developing unit is started and the charging of the developer by the developer filling unit is started and then the image carrier If the detection result of the image density detection means does not reach a predetermined value even after starting driving and forming a toner image on the image carrier, the drive of the developing unit and the image carrier is stopped. .

  An image forming apparatus according to a fifth aspect of the present invention is the image forming apparatus according to any one of the first to fourth aspects, wherein the abnormality of the apparatus occurs when the driving of the developing unit and the image carrier is stopped. Is provided with warning means for warning.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the untransferred toner contacts the image carrier and adheres to the image carrier. It is provided with a cleaning blade for removing water.

  According to a seventh aspect of the present invention, there is provided the image forming apparatus according to any one of the first to sixth aspects, wherein the developing unit is replenished with toner or developer consumed in the developing step. And the developer filling means fills the developing section with a developer from a developer container installed in the supply path.

  An image forming apparatus according to an eighth aspect of the present invention is the image forming apparatus according to any one of the first to seventh aspects, wherein the developer is a two-component developer having a toner and a carrier. It is.

  In the present application, the “state in which no developer is accommodated” in the developing unit is defined to include a case where a slight amount of developer remains in the developing unit. That is, when the developer housed in the developing section is replaced with a new one (when the developer is replaced), the developer in the developing section is not completely removed and a little developer remains. The state is also “a state where no developer is accommodated”.

  In the present invention, when the developing unit is automatically filled with the developer, the developing unit is started to be driven and the developing unit is started to fill the developing unit with the developer filling means, and the development is performed even after a predetermined time has elapsed. When the developer is not carried on the developer carrier, it is assumed that an abnormality has occurred in the developer filling operation, and the drive of the developing unit and the image carrier is stopped. The problem that the image carrier is driven for a long time without being interposed is suppressed. Therefore, it is possible to provide an image forming apparatus in which the developer is charged into the developing portion with a relatively simple configuration and operation without causing problems such as turning over of the cleaning blade.

Embodiment.
Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

First, the configuration and operation of the entire image forming apparatus will be described with reference to FIG.
In FIG. 1, reference numeral 1 denotes an apparatus main body of a tandem color copier as an image forming apparatus, 2 a writing unit that emits laser light based on input image information, and 3 an original conveying unit that conveys an original D to an original reading unit 4. 4 is a document reading unit that reads image information of the document D, 7 is a paper feeding unit that accommodates a recording medium P such as transfer paper, 9 is a registration roller that adjusts the conveyance timing of the recording medium P, and 11Y, 11M, and 11C. , 11BK is a photosensitive drum as an image carrier on which toner images of each color (yellow, magenta, cyan, black) are formed, 12 is a charging unit that charges the photosensitive drums 11Y, 11M, 11C, and 11BK, 13 Is a developing unit (developing device) that develops the electrostatic latent image formed on each of the photosensitive drums 11Y, 11M, 11C, and 11BK, and 14 is each of the photosensitive drums 11Y, 11M, 11C, and 11 A transfer bias roller (primary transfer bias roller) 15 for transferring a toner image formed on K to be superimposed on the recording medium P, 15 collects untransferred toner on each of the photosensitive drums 11Y, 11M, 11C, and 11BK. A cleaning unit is shown.

Reference numeral 16 denotes an intermediate transfer belt cleaning unit that cleans the intermediate transfer belt 17, 17 an intermediate transfer belt on which toner images of a plurality of colors are transferred and superimposed, and 18 a color toner image on the intermediate transfer belt 17 on the recording medium P. A secondary transfer bias roller 20 for transferring the toner image onto the recording medium P indicates a fixing device for fixing an unfixed image on the recording medium P.
Although not shown in the drawing, a carrier (magnetic carrier) and toner (toner particles) of each color (yellow, cyan, magenta, black) are developed above the photosensitive drums 11Y, 11C, 11M, and 11BK. Each color developer container to be supplied to 13 is installed.

Hereinafter, an operation during normal color image formation in the image forming apparatus will be described. Note that FIG. 2 can also be referred to for the image forming process performed on the photosensitive drums 11Y, 11M, 11C, and 11BK.
First, the document D is transported from the document table in the direction of the arrow in the drawing by the transport rollers of the document transport unit 3 and placed on the contact glass 5 of the document reading unit 4. Then, the document reading unit 4 optically reads the image information of the document D placed on the contact glass 5.

  Specifically, the document reading unit 4 scans the image of the document D on the contact glass 5 while irradiating light emitted from an illumination lamp. Then, the light reflected by the document D is imaged on the color sensor via the mirror group and the lens. The color image information of the document D is read for each RGB (red, green, blue) color separation light by the color sensor, and then converted into an electrical image signal. Further, color conversion processing, color correction processing, spatial frequency correction processing, and the like are performed by the image processing unit based on the RGB color separation image signals to obtain yellow, magenta, cyan, and black color image information.

  Then, the image information of each color of yellow, magenta, cyan, and black is transmitted to the writing unit 2. The writing unit 2 emits laser light L (see FIG. 2) based on the image information of each color toward the corresponding photosensitive drums 11Y, 11M, 11C, and 11BK.

On the other hand, the four photosensitive drums 11Y, 11M, 11C, and 11BK (image carriers) rotate in the clockwise direction in FIG. Referring to FIG. 2, a drum drive motor 91 as a first drive unit that rotationally drives the photosensitive drum 11 is driven independently of a development drive motor 92 as a second drive unit that drives the developing unit 13. The charging unit 12 (charging roller) is also rotationally driven.
First, the surfaces of the photoconductor drums 11Y, 11M, 11C, and 11BK are uniformly charged at a portion facing the charging unit 12 (this is a charging process). Thus, a charged potential is formed on the photosensitive drums 11Y, 11M, 11C, and 11BK. Thereafter, the charged surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK reach the irradiation positions of the respective laser beams.
In the writing unit 2, laser light corresponding to the image signal is emitted from the four light sources corresponding to each color. Each laser beam passes through a separate optical path for each of the yellow, magenta, cyan, and black color components (this is an exposure process).

  Laser light corresponding to the yellow component is irradiated on the surface of the first photosensitive drum 11Y from the left side of the drawing. At this time, the yellow component laser light is scanned in the rotation axis direction (main scanning direction) of the photosensitive drum 11Y by a polygon mirror that rotates at high speed. Thus, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 11Y charged by the charging unit 12.

  Similarly, the laser beam corresponding to the magenta component is irradiated onto the surface of the second photosensitive drum 11M from the left side of the paper, and an electrostatic latent image corresponding to the magenta component is formed. The cyan component laser light is applied to the surface of the third photosensitive drum 11C from the left side of the paper, thereby forming an electrostatic latent image of the cyan component. The black component laser beam is applied to the surface of the fourth photosensitive drum 11BK from the left side of the paper, and an electrostatic latent image of the black component is formed.

Thereafter, the surfaces of the photoconductive drums 11Y, 11M, 11C, and 11BK on which the electrostatic latent images of the respective colors are formed reach positions facing the developing unit 13, respectively. Then, the respective color toners are supplied from the developing units 13 onto the photosensitive drums 11Y, 11M, 11C, and 11BK, and the latent images on the photosensitive drums 11Y, 11M, 11C, and 11BK are developed (development process). .)
Thereafter, the surfaces of the photoconductive drums 11Y, 11M, 11C, and 11BK after the development process reach the facing portions of the intermediate transfer belt 17, respectively. Here, a transfer bias roller 14 is installed at each facing portion so as to contact the inner peripheral surface of the intermediate transfer belt 17. Then, the toner images of the respective colors formed on the photosensitive drums 11Y, 11M, 11C, and 11BK are sequentially superimposed and transferred onto the intermediate transfer belt 17 at the position of the transfer bias roller 14 (in the primary transfer process). is there.).

Then, the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK after the transfer process reach positions facing the cleaning unit 15, respectively. Then, the untransferred toner remaining on the photosensitive drums 11Y, 11M, 11C, and 11BK is collected by the cleaning unit 15 (this is a cleaning process). Specifically, referring to FIG. 2, the untransferred toner adhering to the photosensitive drum 11 is mechanically scraped by the cleaning blade 15 a that contacts the photosensitive drum 11 and collected in the cleaning unit 15. .
Thereafter, the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11BK pass through a static elimination lamp (static elimination unit) (not shown), and a series of image forming processes on the photosensitive drums 11Y, 11M, 11C, and 11BK is completed.

On the other hand, the intermediate transfer belt 17 on which the toners of the respective colors on the photosensitive drums 11Y, 11M, 11C, and 11BK are transferred (carrying) are run in the clockwise direction in the drawing and are connected to the secondary transfer bias roller 18. Reach the opposite position. Then, a color toner image carried on the intermediate transfer belt 17 is transferred onto the recording medium P at a position facing the secondary transfer bias roller 18 (secondary transfer step).
Thereafter, the surface of the intermediate transfer belt 17 reaches the position of the intermediate transfer belt cleaning unit 16. Then, the untransferred toner adhered on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaning unit 16, and a series of transfer processes in the intermediate transfer belt 17 is completed.

Here, the recording medium P transported between the intermediate transfer belt 17 and the secondary transfer bias roller 18 (secondary transfer nip) is transported from the paper supply unit 7 via the registration roller 9 and the like. It is a thing.
Specifically, the recording medium P fed by the paper feeding roller 8 from the paper feeding unit 7 that stores the recording medium P is guided to the registration roller 9 after passing through the conveyance guide. The recording medium P that has reached the registration roller 9 is conveyed toward the secondary transfer nip at the same timing.

Then, the recording medium P on which the full-color image is transferred is guided to the fixing device 20 by the transport belt. In the fixing device 20, the color image (toner) is fixed on the recording medium P at the nip between the fixing belt and the pressure roller.
Then, the recording medium P after the fixing step is discharged as an output image outside the apparatus main body 1 by a paper discharge roller, and a series of image forming processes is completed.

Next, the image forming unit in the image forming apparatus will be described in detail with reference to FIGS.
FIG. 2 is a configuration diagram illustrating the image forming unit and the developer container 28. 3A is a schematic cross-sectional view of the upper part of the developing unit 13 (the position of the first conveying screw 13b1) in the longitudinal direction, and FIG. 3B is the lower part of the developing unit 13 (second conveying unit). It is the position of the screw 13b2 and the 3rd conveyance screw 13b3.) It is the schematic sectional drawing which looked at the longitudinal direction. FIG. 4 is a cross-sectional view showing the end of the developing unit 13 (the position of the third relay unit 13h).
Since each image forming unit has almost the same structure and each developer container has almost the same structure, the image forming unit and the developer container are denoted by reference characters (Y, C, M and BK) are shown in the figure.

As shown in FIG. 2, the image forming unit includes a photosensitive drum 11 as an image carrier, a charging unit 12, a developing unit 13 (developing device), a cleaning unit 15, and the like.
The photosensitive drum 11 as an image carrier is a negatively charged organic photosensitive member, and is rotated counterclockwise by a rotation driving mechanism (not shown).

The charging unit 12 is a charging roller having elasticity in which a foamed urethane layer having a medium resistance in which a urethane resin, carbon black as conductive particles, a sulfurizing agent, a foaming agent, and the like are formed in a roller shape on a core metal. The material of the middle resistance layer of the charging unit 12 is urethane, ethylene-propylene-diene polyethylene (EPDM), butadiene acrylonitrile rubber (NBR), silicone rubber, isoprene rubber, etc. It is also possible to use a rubber material in which a conductive material such as the above is dispersed or a foamed material of these materials.
The cleaning unit 15 is provided with a cleaning blade 15 a that is in sliding contact with the photosensitive drum 11, and mechanically removes and collects untransferred toner on the photosensitive drum 11. The cleaning blade 15a is formed of a rubber material such as urethane, EPDM, NBR, silicone, or isoprene. In this embodiment, the contact direction of the cleaning blade 15a with respect to the photosensitive drum 11 is the counter direction, but the contact direction of the cleaning blade 15a with respect to the photosensitive drum 11 can also be the trading direction.

  The developing unit 13 is arranged so that a developing roller 13a as a developer carrying member is close to the photosensitive drum 11, and a developing region where the photosensitive drum 11 and the magnetic brush are in contact with each other is formed. Is done. In the developing unit 13, a developer G (two-component developer) composed of toner T and carrier C is accommodated. The developing unit 13 develops the electrostatic latent image formed on the photosensitive drum 11 (forms a toner image). The configuration and operation of the developing unit 13 will be described in detail later.

Here, the developing unit 13 in the present embodiment is of a premix developing system, and a new carrier C (developer G) is appropriately supplied from the developer container 28 into the developing unit 13. The deteriorated developer G is discharged toward the agent storage container 70 installed outside the developing unit 13.
Referring to FIG. 2, developer container 28 contains developer G (toner T and carrier C) for replenishing the developer consumed in developing unit 13 by the developing process. The developer container 28 functions as a toner cartridge that supplies new toner T to the developing unit 13, and also functions as a supply unit that supplies new carrier C to the developing unit 13. Specifically, the toner concentration (toner in the developer G) detected by a magnetic sensor 86 (installed in the transport path of the third transport screw 13b3) serving as a toner concentration detection unit installed in the developing unit 13. And the image density detected by the optical sensor 40 as the image density detection means facing the photosensitive drum 11 (an image of a patch pattern formed on the photosensitive drum 11 at a predetermined timing). The shutter mechanism 80 is opened / closed by the shutter driving unit 81 based on the information of the density), and the developer G is appropriately replenished from the developer container 28 through the replenishment path into the developing unit 13. .
In the present embodiment, the mixing ratio (toner concentration) of the toner T with respect to the carrier C in the developer G in the developer container 28 is set to be relatively high.

  The supply pipe 29 as a supply path is for reliably guiding the developer G (toner T and carrier C) supplied from the developer container 28 into the developing unit 13. That is, the developer G discharged from the developer container 28 is supplied into the developing unit 13 from the supply port 13 e via the supply pipe 29.

Hereinafter, the developing unit 13 (developing device) in the image forming apparatus will be described in detail.
2 to 4, the developing unit 13 includes a developing roller 13a as a developer carrying member, transport screws 13b1 to 13b3 (auger screws) as a transport member, a doctor blade 13c, and the like.
The developing roller 13 a is configured such that a sleeve formed of a non-magnetic material such as aluminum, brass, stainless steel, or conductive resin in a cylindrical shape is rotated clockwise by a developing drive motor 92. Referring to FIG. 3, a magnet 13 a 1 that forms a magnetic field is fixed in the sleeve 13 a 2 of the developing roller 13 a so as to cause the developer G to rise on the peripheral surface of the sleeve. The carrier C in the developer G rises in a chain shape on the sleeve 13a2 so as to follow the normal line of magnetic force emitted from the magnet 13a1. The charged toner T is attached to the carrier C that is spiked in a chain shape to form a magnetic brush. The magnetic brush is transferred in the same direction (clockwise) as the sleeve 13a2 by the rotation of the sleeve 13a2.

Referring to FIG. 2, the doctor blade 13c is installed on the upstream side of the developing area, and regulates the developer G on the developing roller 13a to an appropriate amount.
The three conveying screws 13b1 to 13b3 stir and mix the developer G accommodated in the developing unit 13 while circulating in the longitudinal direction (the direction perpendicular to the paper surface of FIG. 2).
The first conveying screw 13b1 is disposed at a position facing the developing roller 13a, and conveys the developer G in the horizontal direction (conveying in the right direction indicated by a broken line arrow in FIG. 3A). Then, the developer G is supplied onto the developing roller 13a (the supply in the direction of the white arrow in FIG. 3A).

  The second conveying screw 13b2 is disposed below the first conveying screw 13b1 and at a position facing the developing roller 13a. Then, the developer G separated from the developing roller 13a (the developer G forcibly separated from the developing roller 13a by the agent separation pole after the developing step, and separated in the direction of the white arrow in FIG. 3B). Is transported in the horizontal direction (the transport in the right direction indicated by the broken line arrow in FIG. 3B).

The third transport screw 13b3 is a position adjacent to the second transport screw 13b2, and is disposed obliquely below the first transport member 13b1. The third transport screw 13b3 transports the developer G transported by the second transport screw 13b2 to the upstream side of the transport path by the first transport member 13b1, and from the downstream side of the transport path by the first transport screw 13b1. The developer G circulated through the first relay portion 13f is transported to the upstream side of the transport path by the first transport member 13b1 (the transport in the left direction indicated by the broken-line arrow in FIG. 3B).
The three conveying screws 13b1 to 13b3 are arranged so that the rotation shaft is substantially horizontal, like the developing roller 13a and the photosensitive drum 11. The developing roller 13a and the three conveying screws 13b1 to 13b3 are rotationally driven by a developing driving motor 92 as a second driving unit through a gear train (not shown).

In addition, the conveyance path by the 1st conveyance screw 13b1, the conveyance path by the 2nd conveyance screw 13b2, and the conveyance path by the 3rd conveyance screw 13b3 are isolated by the wall part.
With reference to FIG. 3 (B), the downstream side of the conveyance path by the second conveyance screw 13b2 and the upstream side of the conveyance path by the third conveyance screw 13b3 communicate with each other via the second relay portion 13g. Also, referring to FIGS. 3A and 3B, the downstream side of the conveyance path by the first conveyance screw 13b1 and the upstream side of the conveyance path by the third conveyance screw 13b3 are the first relay portion 13f. It communicates through. Further, referring to FIGS. 3A, 3B, and 4, the downstream side of the transport path by the third transport screw 13b3 and the upstream side of the transport path by the first transport screw 13b1 are the third. It communicates via the relay part 13h. Referring to FIG. 4, the developer G staying and rising in the vicinity of the third relay portion 13 h in the transport route by the third transport screw 13 b 3 is transported by the first transport screw 13 b 1 via the third relay portion 13 h. It is conveyed (supplied) to the upstream side.

With such a configuration, a circulation path for circulating the developer G in the longitudinal direction in the developing unit 13 is formed by the three conveying screws 13b1 to 13b3. That is, when the developing unit 13 is driven by the developing drive motor 92 as the second driving unit, the developing roller 13a and the three transport screws 13b1 to 13b3 rotate, and the developer G accommodated in the apparatus is illustrated in FIG. It flows in the direction of the dashed arrow in 3. In this way, the developer G supply path to the developing roller 13a (the transport path by the first transport screw 13a1) and the developer G recovery path to be separated from the developing roller 13a (by the second transport screw 13a2). , The density deviation of the toner image formed on the photosensitive drum 11 can be reduced.
Although illustration is omitted, a magnetic sensor 86 as a toner concentration detecting means for detecting the toner concentration of the developer circulating in the apparatus is installed in the conveyance path by the third conveyance screw 13b3. Then, based on the toner density information detected by the magnetic sensor 86 (or the image density information detected by the optical sensor 40), the developer container 28 passes through the supply path (supply pipe 29, supply port 13e). Thus, a developer G having a predetermined toner concentration is supplied into the developing unit 13.

Here, referring to FIGS. 2 and 3, a part of the developer G accommodated in the developing unit 13 is discharged to the outside (agent storage container 70) in the transport path by the first transport screw 13b1. A discharge port 13d is provided. Specifically, the discharge port 13d has a developer surface (upper surface) of the developer that is supplied from the developer container 28 into the developing unit 13 to increase the amount of developer in the apparatus and is conveyed to that position. When the predetermined height is exceeded, the excess developer G is discharged toward the agent storage container 70. That is, the excess developer G exceeds the lower portion of the discharge port 13d, is discharged from the discharge port 13d, and falls by its own weight toward the agent storage container 70 via the discharge path. As described above, the carrier deteriorated by being contaminated by the base resin or the external additive of the toner T is automatically discharged to the outside of the developing unit, so that deterioration of the image quality can be suppressed even over time.
In the present embodiment, the replenishment port 13e and the discharge port 13d are disposed in the transport path by the first transport screw 13a1, but the positions of the replenishment port 13e and the discharge port 13d are not limited to this.

Hereinafter, the control performed when the developer is filled, which is characteristic in the present embodiment, will be described in detail.
FIG. 5 is a timing chart showing control at the time of developer filling, and will be referred to as appropriate in the following description.

  The image forming apparatus according to the present embodiment is shipped from the factory in a state where the developer is not contained in the developing unit 13 (the inside of the developing unit 13 is empty) in order to prevent the developer from scattering. Is done. Then, it is installed (delivered) under the user through a transportation process by land, air, etc. and a storage process at a store. Then, at the time of installation (delivery), the developer (initial agent) is filled (supplied) into the empty developing unit 13 immediately before the initial setting or operation check of the image forming apparatus is performed at the user installation location. .

In the present embodiment, the developer is charged into the developing unit 13 not automatically but automatically. The procedure will be described in detail below.
First, with the empty developing section 13 installed in the apparatus main body 1, the developer container for the initial agent is installed at the place where the developer container 28 is installed (not necessarily equivalent to the capacity of the developer container 28 described in FIG. 2). Is not necessary.) Then, using the supply paths 13e and 29 described with reference to FIG. 2, the developer is charged while the developing unit 13 is driven. That is, the developer filling unit in the present embodiment is a unit that operates the development driving motor 92 (second driving unit) to fill the developing unit 13 with the developer. In other words, the driving means used when the developer is filled is a driving means used during the developing process. The developer container is installed in the apparatus main body 1 after taking out the cap (or seal) installed in the opening (the opening for discharging the developer).

  Specifically, when a service man (or user) operates a button (an operation button for performing developer filling, which is not shown) of the operation unit of the apparatus main body 1, the shutter is controlled by the control unit 87. The mechanism 80 is opened and the developing drive motor 92 is operated. As a result, the developer in the developer container flows into the developing unit 13 through the replenishment path, and the developer in the developing unit 13 is driven by the rotation of the developing roller 13a and the three transport screws 13b1 to 13b3. Circulation starts. Thus, the amount of developer in the developing unit 13 gradually increases. In the present embodiment, the capacity of the developer stored in the developer container for filling is set to 500 to 600 grams.

Here, in this embodiment, when the developer is newly filled in the developing unit 13 in a state where the developer is not accommodated (when the developer is filled), the development drive motor 92 (second drive unit). ) Is started to drive the developing unit 13, and after the developer filling unit starts to charge the developer, the drum driving motor 91 (first driving unit) is started to start driving the photosensitive drum 11. You are in control. That is, referring to FIG. 5, at the start of developer filling, drum driving motor 91 is not operated (photosensitive drum 11 is not rotationally driven), and only developing driving motor 92 is operated (developing unit). Only 13 is driven.). Then, after detecting that the operation time of the developing drive motor 92 has passed a predetermined time (2 seconds in the present embodiment) by the timer 85, the drum drive motor 91 is operated to rotate the photosensitive drum 11. Start driving.
In this way, the photosensitive drum 11 is not driven to rotate at the same time as the start of developer filling, but is driven after the developer has been charged for a while, so that the photosensitive drum 11 is driven to rotate so that the cleaning blade comes into contact with the photosensitive drum 11. The load on 15a is reduced. That is, the problem that the photosensitive drum 11 is driven for a long time in a state where no toner is present in the edge portion (contact portion) of the cleaning blade 15a is suppressed. Therefore, the trouble that the cleaning blade 15a is turned over is suppressed.

Further, in the present embodiment, the developer driving motor 92 is operated to start driving the developing unit 13 and the developer charging unit starts charging the developer, and the developer starts to be carried on the developing roller 13a. Immediately before, the drum drive motor 91 is operated so as to start driving the photosensitive drum 11. That is, the developer filling is started, the developer gradually spreads throughout the developing unit 13, and the rotation of the photosensitive drum 11 is started immediately before the developer is supplied onto the developing roller 13a.
As a result, when the developer starts to be carried on the developing roller 13a, the photosensitive drum 11 rotates, not stopped, so that the developer carried on the developing roller 13a is rotated. A problem that the surface of the drum is scratched intensively in contact with a part of the surface is suppressed. Further, since toner (toner due to background contamination) is immediately supplied onto the photosensitive drum 11 that has started rotating, the toner is also immediately applied to the edge portion (contact portion) of the cleaning blade 15a. As a result, the cleaning blade 15a is prevented from being turned over.
Note that the predetermined time detected by the timer 85 (2 seconds in the present embodiment) is the time from the start of developer filling to just before the developer is supplied onto the developing roller 13a. Therefore, it is a value determined by experiments and simulations during the development of the device.

In the present embodiment, after the developer filling is started, the rotation of the photosensitive drum 11 is started after the timer 85 detects that the operation time of the development drive motor 92 has reached a predetermined time.
On the other hand, after the developer filling is started, the rotation of the photosensitive drum 11 may be started after the detection result of the magnetic sensor 86 (toner density detecting means) reaches a predetermined value. Specifically, as shown in FIG. 6, when the developer is almost spread over the developing unit 13 after the empty developer unit 13 is started to be charged, the developing is also performed in the vicinity of the magnetic sensor 86. The agent spreads sufficiently and the sensor output rises rapidly. Therefore, when the output of the magnetic sensor 86 reaches the predetermined value A (a sufficiently increased value), it is assumed that the developer starts to be carried on the developing roller 13a, and the photosensitive drum 11 is rotationally driven. Start. Even in such a case, the same effect as the present embodiment can be obtained. In order to ensure such control, it is preferable to install the magnetic sensor 86 on the upstream side of the conveyance path by the first conveyance screw 13b1.

  In addition, referring to FIG. 2, a torque detection sensor 84 is installed as a torque detection means for detecting the driving torque of the developing unit 13, and the detection result of the torque detection sensor 84 (torque detection means) after starting the developer filling After reaching the predetermined value, the rotational drive of the photosensitive drum 11 may be started. Specifically, as shown in FIG. 7, when the developer is almost spread over the developing unit 13 after the empty developer unit 13 is started to be charged, the developing roller 13 a and the three conveying screws are used. The load applied to 13b1 to 13b3 increases, and the driving torque of the developing unit 13 increases rapidly. Therefore, when the output of the torque detection sensor 84 reaches the predetermined value B (a sufficiently increased value), it is assumed that the developer starts to be carried on the developing roller 13a, and the photosensitive drum 11 is rotationally driven. To start. Even in such a case, the same effect as the present embodiment can be obtained. As the torque detection sensor 84, a sensor that detects fluctuations in the current value supplied to the development drive motor 92 can be used.

Here, in the present embodiment, when the developer filling control described above is performed, the developer remains on the developing roller 13a even if a predetermined time (for example, 2 seconds later) elapses after the start of the developer filling. When the toner is not carried, it is assumed that an abnormality has occurred in the developer filling means, and the operations of the development drive motor 92 and the drum drive motor 91 are stopped. Then, a display (warning) that an abnormality has occurred in the developer filling operation is displayed on the display unit 88 of the apparatus main body 1.
Thereby, even if the developer filling is not performed correctly even if the developer filling is started, such as forgetting to remove the cap (or seal) installed at the opening of the developer container. The problem that the photosensitive drum 11 is driven for a long time without toner being supplied to the edge portion of the cleaning blade 15a is suppressed. That is, it is possible to accurately detect an abnormality in the developer filling unit and suppress the occurrence of a malfunction due to the abnormality.

Specifically, in the above-described abnormality detection control, when the detection result of the magnetic sensor 86 (toner density detection means) does not reach the predetermined value A even after a predetermined time has elapsed after the start of developer filling, the development drive motor 92 and The operation of the drum drive motor 91 is stopped. That is, the magnetic sensor 86 detects that the developer is not carried on the developing roller 13a even if a predetermined time has elapsed after the start of the developer filling.
When the detection result of the torque detection sensor 84 (torque detection means) does not reach the predetermined value B even after a predetermined time has elapsed after the start of charging the developer, the operation of the development drive motor 92 and the drum drive motor 91 is stopped. May be.
Further, the detection result of the optical sensor 40 (image density detection means) even after a toner image (patch pattern) is formed on the photosensitive drum 11 after the start of filling of the developer and the driving of the photosensitive drum 11 is started. When the toner does not reach the predetermined value (when the image density of the patch pattern is low), it is assumed that an abnormality has occurred in the developer filling means and a normal patch pattern cannot be formed on the photosensitive drum 11, and development drive is performed. The operation of the motor 92 and the drum drive motor 91 may be stopped.
In these cases as well, it is possible to accurately detect an abnormality in the developer filling means and suppress the occurrence of problems due to the abnormality.

  In the present embodiment, the display unit is used as a warning unit that warns of an abnormality in the apparatus when the driving of the developing unit 13 and the photosensitive drum 11 is stopped (when an abnormality in the developer filling operation is detected). Warning display to 88. However, the warning means is not limited to this, and may be a voice warning, for example. Also in this case, as in the present embodiment, it is possible to notify the service person or the user of the abnormality of the apparatus.

  Further, in the present embodiment, even if a predetermined time has elapsed after the start of developer filling, a state in which the developer is not carried on the developing roller 13a is detected and the developer filling operation is abnormal. It is possible to detect a state in which the developer is not discharged from the filling developer container even after a predetermined time has elapsed, and to make the developer filling operation abnormal. It is also possible to detect the state where the developer is not circulated in the state 13 and to make the developer filling operation abnormal. These technical meanings are almost the same as those of the abnormality detection control in the present embodiment.

Here, in the present embodiment, after the start of the developer filling, the period from the start of the driving of the photosensitive drum 11 to the end of the filling of the developer into the developing unit 13 (in the present embodiment, The toner image is formed on the photosensitive drum 11 in about 30 seconds.
Specifically, after a developer is carried on the developing roller 13a and driving of the photosensitive drum 11 is started, a belt-like toner image is formed over the entire image forming width of the photosensitive drum 11 at a predetermined timing. Specifically, referring to FIG. 5, a strip pattern is formed on the photosensitive drum 11 by turning off the charging DC bias for about 1 second 10 seconds after the start of developer filling.
Since the belt-like pattern reaches the cleaning blade 15a as it is, toner is positively supplied to the entire edge portion of the cleaning blade 15a, and the cleaning blade 15a is prevented from being turned over by the toner intervening in the edge portion.

Hereinafter, an example of the developer filling control described above will be described more specifically with reference to FIG.
First, when preparations such as setting of a developer container for filling are completed and an operation button for filling the developer is pressed, driving of the developing unit 13 is started, and developer filling from the developer container is started. Start (step S1 to step S2).

Thereafter, it is determined whether the developer filling time has reached a predetermined time T1 (for example, 2 seconds) (step S3). As a result, when it is determined that the developer filling time has reached the predetermined time T1, the toner concentration of the developer in the developing unit 13 is detected by the magnetic sensor 86 (toner concentration detecting means), and the detection result is determined in advance. It is determined whether the value A has been reached (step S4).
As a result, when it is determined that the detection result of the magnetic sensor 86 has not reached the predetermined value A, it is determined that an abnormality has occurred in the developer filling operation, and the operations of the development drive motor 92 and the drum drive motor 91 are stopped ( Step S10). Thereafter, an abnormality warning is given to the display unit 88 as a warning means (step S11), and this flow is ended (step S12). The “stop driving of the drum drive motor 91” in step S10 includes an operation that does not start driving a drum drive motor that has not started driving.

On the other hand, if it is determined in step S4 that the detection result of the magnetic sensor 86 has reached the predetermined value A, it is assumed that the developer filling operation is normally performed and the photosensitive drum 11 is driven. Is started (step S5).
Then, a belt pattern is formed on the photosensitive drum 11 (step S6), and toner is positively supplied to the edge portion of the cleaning blade 15a. Thereafter, after a predetermined time (about 30 seconds) has elapsed, the developer filling is finished (step S7), the driving of the developing unit 13 and the photosensitive drum 11 is stopped (step S8), and this flow is performed. The process ends (step S9).

  As described above, in the present embodiment, when the developing unit 13 is automatically filled with the developer, the driving of the developing unit 13 is started and the developing unit 13 is charged with the developer by the developer filling unit. When the developer is not carried on the developing roller 13a (developer carrying member) even after a predetermined time has elapsed since the start, it is assumed that an abnormality has occurred in the developer filling operation and the developing unit 13 and the photosensitive drum 11 Since the driving of the (image carrier) is stopped, the problem that the photosensitive drum 11 is driven for a long time without toner intervening at the edge portion of the cleaning blade 15a is suppressed. Therefore, the developer is charged into the developing unit 13 with a relatively simple configuration and operation without causing problems such as turning over of the cleaning blade 15a.

In the present embodiment, since a premix development method (a development method in which the developer is replenished / discharged with respect to the developing unit 13) is used, an empty development is performed at the time of installation (delivery). After the portion 13 is filled with the developer, the developer is not basically exchanged. Therefore, the developer filling control in this embodiment is performed only at the time of installation (during delivery).
However, with respect to a developing system that replaces the developer (a developing system that only replenishes the toner from the replenishment path in accordance with the developing process), the developer contained in the developing unit 13 (the existing deteriorated developer) )) Is taken out from the developing unit 13, and then the developer charging control in the present embodiment is performed on the empty developing unit 13. Even in that case, the same effect as the present embodiment can be obtained.
In this case, it is preferable that the operation of taking out the developer stored in the developing unit 13 from the developing unit 13 is automatically performed. Specifically, an openable and closable opening (normally closed) is provided at the bottom in the transport path of the developing unit, and the developer is discharged from the opening while driving the developing unit 13. In that case, it is preferable that the developer discharge control adopts the technical concept of the developer filling control in the present embodiment.

  In the present embodiment, the present invention is applied to the developing unit 13 in which three conveying screws 13b1 to 13b3 as conveying members are installed. However, the developing unit in which two or four or more conveying screws are installed. The present invention can also be applied to. Moreover, in this Embodiment, although the 3rd conveyance screw 13b3 was arrange | positioned horizontally, the 3rd conveyance screw 13b3 can also be arrange | positioned diagonally with respect to a horizontal direction.

  In this embodiment, the developer G (toner T and carrier C) is supplied from the developer container 28 toward the developing unit 13, but only the carrier C is supplied from the developer container (carrier container) to the developing unit 13. It can also be supplied. In that case, a toner container containing only toner is installed separately from the developer container (carrier container), and the toner contained in the toner container based on the detection result of the magnetic sensor 86 or the optical sensor 40 is developed by the developing unit 13. It will be replenished appropriately toward the. Even in such a case, the same effect as in the present embodiment can be obtained.

  Further, in the present embodiment, the present invention is applied to an image forming apparatus in which the developing unit 13 is configured as a unit that is detachably attached to the main body of the image forming apparatus. However, the application of the present invention is not limited to this, and the present invention can naturally be applied to an image forming apparatus in which the image forming unit is a process cartridge. In the process cartridge, at least one of the charging unit 12, the developing unit 13, and the cleaning unit 15 and the image carrier 11 are integrated and detachably installed in the image forming apparatus main body 1. Is a unit.

  It should be noted that the present invention is not limited to the present embodiment, and it is obvious that the present embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in the present embodiment. is there. In addition, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, and the number, position, shape, and the like suitable for implementing the present invention can be achieved.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. It is a block diagram which shows an image creation part. (A) The schematic sectional drawing which looked at the upper part of the image development part in the longitudinal direction, (B) The schematic sectional drawing which looked at the lower part of the image development part in the longitudinal direction. It is sectional drawing which shows the edge part of the image development part. It is a timing chart which shows the control at the time of developer filling. It is a graph which shows the relationship between a developer filling time and a magnetic sensor output. It is a graph which shows the relationship between developer filling time and development torque. It is a flowchart which shows the control at the time of a developer filling.

Explanation of symbols

1 image forming apparatus body (apparatus body),
11, 11Y, 11C, 11M, 11BK Photosensitive drum (image carrier),
13 Developing section (developing device),
13a Development roller (developer carrier),
13e Supply port (supply route),
15a cleaning blade,
28 developer container,
29 Supply pipe (supply route),
40 Optical sensor (image density detection means),
84 Torque detection sensor (torque detection means),
85 timer,
86 Magnetic sensor (toner concentration detection means),
88 Display (warning means),
91 drum drive motor (first drive unit),
92 Development drive motor (second drive unit),
G developer (two-component developer), T toner, C carrier.

Claims (8)

An image carrier;
A developing unit for developing a latent image formed on the image carrier;
Developer filling means for filling the developer with developer while driving the developer;
With
The developing section includes a developer carrying body that faces the image carrying body and carries a developer,
When a new developer is filled in the developing unit in a state where the developer is not accommodated, the driving of the developing unit is started and filling of the developer by the developer filling unit is started and a predetermined time has elapsed. However, when the developer is not carried on the developer carrying member, the image forming apparatus stops driving the developing unit and the image carrying member. A toner concentration detecting means for detecting the toner concentration of the developer contained in the developing unit;
When a new developer is filled in the developing unit in a state where the developer is not accommodated, the driving of the developing unit is started and filling of the developer by the developer filling unit is started and a predetermined time has elapsed. 2. The image forming apparatus according to claim 1, wherein when the detection result of the toner density detection unit does not reach a predetermined value, the driving of the developing unit and the image carrier is stopped. A torque detecting means for detecting a driving torque of the developing unit;
When a new developer is filled in the developing unit in a state where the developer is not accommodated, the driving of the developing unit is started and filling of the developer by the developer filling unit is started and a predetermined time has elapsed. 2. The image forming apparatus according to claim 1, wherein when the detection result of the torque detection unit does not reach a predetermined value, driving of the developing unit and the image carrier is stopped. Image density detecting means for detecting the image density of the toner image formed on the image carrier,
In the case where a new developer is filled in the developing unit in a state where the developer is not accommodated, the image carrier is started after starting the driving of the developing unit and starting the filling of the developer by the developer filling unit. If the detection result of the image density detecting means does not reach a predetermined value even if the toner image is formed on the image carrier by starting the driving of the developing unit, the driving of the developing unit and the image carrier is stopped. The image forming apparatus according to claim 1, wherein:   5. The image forming apparatus according to claim 1, further comprising a warning unit that warns of an abnormality of the apparatus when driving of the developing unit and the image carrier is stopped.   The image forming apparatus according to claim 1, further comprising: a cleaning blade that contacts the image carrier and removes untransferred toner attached to the image carrier. A replenishment path for replenishing the developing unit with toner or developer consumed in the development process;
The image forming apparatus according to claim 1, wherein the developer filling unit fills the developing portion with a developer from a developer container installed in the replenishment path.   The image forming apparatus according to claim 1, wherein the developer is a two-component developer having a toner and a carrier.

Images