JP2004341220A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of further shortening a period of time required for filling toner than heretofore and remarkably shortening by which installation time and replacement time when newly installing the image forming apparatus and when newly replacing only a developing device. <P>SOLUTION: The image forming apparatus comprises a mode changeover control means to switch an initialization mode in which image forming is made feasible by replenishing the toner from a toner container when a developing container does not have the toner at all, and a standard mode in which the toner is replenished to the developing container from the toner container in an image formation enable state. A toner replenishing amount in the initialization mode is set larger than that in the standard mode, and the driving speed of a developing roller 16 in the initialization mode is set lower than that of the developing roller 16 in the standard mode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Industrial applications]
The present invention relates to an image forming apparatus provided with a developing unit for developing an electrostatic latent image formed on an image bearing unit into a toner image.
[0002]
[Prior art]
As an image forming apparatus such as a copying machine, a printer, and a facsimile, an electrostatic latent image is formed on an image carrier, the electrostatic latent image is developed into a toner image, and the toner image is formed on a sheet member (for example, plain paper). 2. Description of the Related Art An image forming apparatus of a transfer type has been widely put to practical use.
The image forming apparatus includes, in addition to the image carrying unit, an electrostatic latent image forming unit for forming an electrostatic latent image on the image carrying unit, and an electrostatic latent image on the image carrying unit for developing the electrostatic latent image on the image carrying unit into a toner image. Developing means, transferring means for transferring the toner image on the image bearing means onto the sheet member, and transferring the toner image on the image bearing means onto the sheet member and transferring the toner remaining on the image bearing means to the image bearing means A cleaning unit for removing from above is provided (the cleaning unit may be omitted).
[0003]
As a developing means, a two-component developing method using a two-component developer composed of toner and carrier particles and a one-component developing method using a magnetic or non-magnetic toner are generally known. The one-component developing system is superior in terms of the life of the developer and the like.
[0004]
In the one-component developing system, for example, a so-called process unit system in which a developing unit, an image carrying unit (for example, a photosensitive drum), a cleaning unit, and the like are integrally united and detachable from an image forming apparatus is often used. . In this method, the developing device is pre-filled with toner, and the process unit is replaced when the toner is consumed by the image formation and becomes empty. The used process units are refilled with toner, replaced with photosensitive drums, etc., and are reused or discarded.
On the other hand, in the two-component developing method, a method in which a toner container filled with a replenishing toner is mounted on a developing device to replenish the toner has conventionally been used. By using a long-life photoreceptor such as an amorphous silicon photoreceptor, a system for replenishing such a toner in a one-component developing system is increasing. In such a replenishment method, since only the toner container is replaced, it is possible to reduce member costs, toner refilling costs, disposal costs, and the like as compared with the process unit method, and to reduce image forming costs. A great effect is expected.
[0005]
In the toner supply method, various methods have been proposed for toner supply. Japanese Patent Application Laid-Open No. 8-15984 discloses a method of supplying toner from above to a conveying / stirring mechanism arranged in parallel with a developing roller. When the agent setting mode is selected, the toner replenishing unit is continuously driven for a predetermined time (for example, three minutes) from the start of toner filling, and thereafter, the hopper is turned on (for example, two seconds) and OFF (for example, one second) intermittently. There is disclosed a control for shortening the time until an image can be formed.
[Patent Document 1]
JP-A-8-15984
[Problems to be solved by the invention]
[0006]
However, as described in the above publication, generally, the driving of the developing roller and the driving of the conveying / stirring mechanism are controlled by the same driving system, and are driven to rotate at the same driving speed. However, in such a drive control, if the toner replenishment amount is increased and the filling time is reduced at the time of toner filling, the developing roller is also driven to rotate at the time of toner filling as well as at the time of image formation. The toner is overcharged on the roller, which causes a problem in image formation such as a decrease in image density.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, reduce the time required for toner filling, significantly reduce installation time and replacement time when newly installing an image forming apparatus or replacing only a developing device. Another object of the present invention is to provide an image forming apparatus capable of forming a good image.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, an image forming apparatus according to the present invention includes an image carrying unit, an electrostatic latent image forming unit for forming an electrostatic latent image on the image carrying unit, and an image forming unit on the image carrying unit. At least developing means for developing the electrostatic latent image into a toner image, and transfer means for transferring the toner image on the image carrying means onto a sheet member, wherein the developing means comprises A container, a developing application unit for applying the toner in the developing container onto the image bearing unit, and a conveying / stirring unit disposed in the developing container. A circulation path including an upstream path and a downstream path extending in parallel to each other is defined. The upstream path and the downstream path are communicated with each other at both ends in the width direction, and The agitating means is located upstream in the upstream path; A transport / stirring mechanism, a downstream transport / stirring mechanism disposed on the downstream path, wherein the developing application unit includes a developing roller extending in a width direction along the downstream path; The toner present in the developing roller is pumped to the peripheral surface of the developing roller and is applied to the image carrying means. In the image forming apparatus, a toner supply port is provided above the upstream path, and is detachably attached to the developing container. A toner container for storing replenished toner having a toner dropping port at a position facing the toner replenishing port, wherein toner can be supplied from the toner container into the developing container so that image formation is possible. And a mode switching control unit that switches between a normal mode in which toner is supplied from the toner container to the developing container in a state where image formation is possible. The toner supply amount in the initialization mode is set to be larger than the toner supply amount in the standard mode, and the driving speed of the developing roller in the initialization mode is set higher than the driving speed of the developing roller in the standard mode. Is also set to be small.
[0009]
Preferably, in the image forming apparatus of the present invention, the drive of the developing roller is stopped in the initialization mode.
[0010]
More preferably, in the image forming apparatus of the present invention, the drive speed of the developing roller is changed to be the same as the drive speed in the standard mode after a lapse of a predetermined time from the start of toner supply in the initialization mode. I do. Alternatively, a toner amount detecting unit is provided on an upstream side path of the developing container, and in the initialization mode, when the toner amount detecting unit detects a toner amount in a state where an image can be formed after toner supply is started. The driving speed of the developing roller is changed to the same as the driving speed in the standard mode.
[0011]
[Operation of the present invention]
According to the present invention, the toner supply amount in the so-called initialization mode in which only the image forming apparatus or the developing device is newly installed is set to be larger than the toner supply amount in the standard mode in which image formation is repeatedly performed. The driving speed of the developing roller in the initialization mode is set lower than the driving speed of the developing roller in the standard mode, or the driving of the developing roller in the initialization mode is stopped. For this reason, it is possible to shorten the time for filling the toner into the vicinity of the developing roller inside the developing device, and to form a good image because the toner is not overcharged on the developing roller.
[0012]
Further, in the initialization mode, after a lapse of a predetermined time from the start of toner supply, the drive speed of the developing roller is changed to be the same as the drive speed in the standard mode, or the toner amount is changed to the upstream path of the developing container. A detection unit provided in the initialization mode, and when the toner amount detection unit detects the amount of toner in a state where an image can be formed after the toner supply is started, the driving speed of the developing roller is set to a value in the standard mode. Change to the same speed.
That is, as soon as toner filling is completed, the driving speed of the developing roller is changed to the same as the driving speed in the standard mode, and the toner on the developing roller can be charged so that an image can be formed.
[0013]
【Example】
The present invention is suitably used in an image forming apparatus having one-component developing means. However, even if a large amount of toner is replenished, for example, by improving the structure of the stirring mechanism, it is possible to efficiently mix and stir the carrier and the toner, and start up to a charge amount capable of forming an image in a short time. It is applicable also in.
As an example, a schematic sectional view of the image forming apparatus of the present invention is shown in FIG. The image forming apparatus has a photosensitive drum 2 as an image bearing unit that rotates in a direction indicated by an arrow 1. The surface of the photosensitive drum 2 is uniformly charged to, for example, a positive polarity by the action of the corona discharger 33, and then the photosensitive drum 2 is irradiated with light by the exposure means 34 according to the image to be formed, and the charge is selected. And an electrostatic latent image is formed on the photosensitive drum 2. The toner is applied to the electrostatic latent image on the photoreceptor drum 2 by the operation of the developing means indicated by reference numeral 3 as a whole, and the electrostatic latent image is developed into a toner image. The toner image on the photosensitive drum 2 is transferred to a sheet member (paper) 35 to be conveyed. At this time, a transfer discharge current is applied from the transfer roller 36 to the back surface of a sheet member such as plain paper. Then, the residual toner is removed from the photosensitive drum 2 by the action of the cleaning blade 37. In the one-component developing device, the cleaning unit may be omitted.
[0014]
As an example, FIG. 2 shows a schematic plan view of a one-component developing device included in the image forming apparatus of the present invention. Referring to FIG. 2 together with FIG. 1, the developing means 3 has a developing container 4. The developing container 4 has a bottom wall 5, a rear wall 6, both side walls 7 and 8, and an upper wall 9. The bottom wall 5 is also integrally formed with a separation wall 10 protruding substantially vertically upward from the bottom wall 5 except for both side portions thereof, and a space in the developing container 4 is separated by the separation wall 10 into an upstream path 11. And a downstream path 12. The upstream path 11 is provided with an upstream transfer / stirring mechanism 13, and the downstream path 12 is provided with a downstream transfer / stirring mechanism 14. The transport / stirring mechanism includes, for example, a rotating shaft extending in the width direction in the path, and a spiral blade disposed on a peripheral surface of the rotating shaft.
[0015]
The developing container 4 is also provided with a developing applying means 15. The developing means 15 has a developing roller 16 extending in the width direction along the downstream-side conveying / stirring mechanism 14, and a stationary magnet member is disposed inside the developing roller 16. An opening 17 extending in the width direction is formed on the front surface of the developing container 4, and the developing roller 16 of the developer applying unit 15 partially protrudes forward through the opening 17 to form the photosensitive drum. 2 is close to the peripheral surface. A toner regulating member 18 is fixed to the upper wall 9 of the developing container 4. The toner regulating member 18 is disposed substantially vertically toward the developing roller 16, and a gap of about 0.2 to 0.4 mm is formed between the tip of the toner regulating member 18 and the peripheral surface of the developing roller 16. Have been.
[0016]
The developing container 4 contains a one-component toner 19. The one-component toner 19 is conveyed from one end to the other end of the upstream path 11 as indicated by an arrow 20 while being agitated by the action of the upstream conveying / stirring mechanism 13. The other end of the side path 11 is moved to the other end of the downstream path 12. In the downstream path 12, the downstream transport / stirring mechanism 14 transports the one-component toner 19 from the other end toward one end as shown by an arrow 22 while stirring the one-component toner 19, and then feeds the downstream toner as shown by an arrow 23. It moves from one end of the path 12 to one end of the upstream path 11. Thus, the one-component toner 19 circulates through the upstream path 11 and the downstream path 12.
[0017]
The developing roller 16 of the developer applying unit 15 rotates in a direction indicated by an arrow 24 in FIG. 1 and holds the one-component toner 19 on the peripheral surface thereof. The toner image is applied to the latent image, and is selectively adhered to the photosensitive drum 2 to be developed into a toner image. The toner regulating member 18 regulates the amount of the one-component toner 19 held on the peripheral surface of the developing roller 16 and carried to the development area, and additionally charges the one-component toner 19.
By repeating the image formation, the one-component toner 19 is consumed, and the toner replenishing means, for example, the toner replenishing roller 26 is rotated from the toner storage container 25 removably installed in the developing container 4 into the developing container 4. The supply toner 27 is supplied. A toner supply port 28 is formed in the upper wall 9 of the toner developing container 4, and a toner drop port 29 is formed in the toner storage container 25 at a position facing the toner supply port 28. The toner is supplied to the upstream path 11 through the toner supply port 28.
[0018]
FIG. 3 is a block diagram showing a part of control-related elements provided in the image forming apparatus of the present invention. The image forming apparatus according to the present invention includes an initialization mode 42 in which toner is supplied from the toner storage container 25 into the developing container 4 so that an image can be formed, and a toner storage in the developing container 4 when an image can be formed. The toner replenishment control unit 40 includes a mode switching control unit 41 that switches between a standard mode 43 for replenishing toner from the container 25 and the standard mode 43.
The initialization mode 42 is a mode in which toner is supplied into the developing container 4 when the image forming apparatus is newly installed or when only the developing device is newly replaced due to a problem occurring in the developing device. This is a mode in which image formation is possible. The standard mode 43 is a mode in which the toner is replenished when the toner in the developing container 4 is consumed by the repetition of the image formation as described above.
[0019]
An example of a toner supply control method in the image forming apparatus of the present invention will be described with reference to a control-related block diagram shown in FIG. 3 and a flowchart shown in FIG. For example, when a new image forming apparatus is installed, a service person inputs a simulation number, which is not known to a general user, using an operation hard key of the image forming apparatus operation unit. On the operation liquid crystal panel, for example, operation soft keys for various settings such as “development bias setting”, “exposure amount setting”, and “developer initialization mode setting” are displayed. When the serviceman presses the "developer initialization mode setting" soft key, the display area of the soft key is displayed in reverse video from white to black, and the initialization mode shown in step N-1 (FIG. 4) is started. You.
In step N-2 (FIG. 4), the transport / stirring mechanism is controlled by the transport / stirring mechanism drive controller 44 (FIG. 3), the toner supply roller drive controller 45 (FIG. 3), and the developing roller drive controller 46 (FIG. 3). The driving of the mechanisms 13 and 14, the continuous driving of the toner supply roller 26, and the driving of the developing roller 16 are started.
At this time, the driving of the developing roller 16 and the driving of the conveying / stirring mechanisms 13 and 14 are controlled by different driving systems, and the driving speed of the developing roller 16 in the standard mode is controlled by the developing roller drive control means 46 (FIG. 3). It is set smaller than the driving speed.
In the case of this embodiment, the driving speed of the developing roller 16 in the standard mode is set to 300 rpm, and the driving speed in the initialization mode is set to 150 rpm. It is preferable that the drive speed in the initialization mode be set to 2/3 or less of the drive speed in the standardization mode. Further, as described above, the driving speed of the developing roller 16 in the initialization mode may be lower than the driving speed in the standardization mode, or the driving of the developing roller 16 in the initialization mode may be stopped.
To increase the toner supply amount in the initialization mode, the toner supply roller 26 is continuously driven in the present embodiment. For example, the driving speed of the toner supply roller 26 is set to be higher than in the standardization mode. Alternatively, when the toner supply roller 26 is intermittently driven, the ratio of the ON time to the drive OFF time may be larger than that in the standard mode.
[0020]
In step N-3 (FIG. 4), the transport / stirring mechanism driving time measurement control means 47 (FIG. 3) determines whether a predetermined time has elapsed since the start of driving of the transporting / stirring mechanisms 13 and 14. . In the present embodiment, the predetermined time is 180 seconds, and when 180 seconds have elapsed, the process proceeds to step N-4 (FIG. 4), and the driving speed of the developing roller 16 is standardized by the developing roller drive control means 46 (FIG. 3). The driving speed in the mode is increased (or the driving of the stopped developing roller 16 is started to increase the driving speed in the standardized mode), and the toner replenishing roller drive control means 45 (FIG. 3) continuously drives the developing roller 16. The toner supply roller 26 is driven intermittently to keep the toner conveyance amount constant.
In the present embodiment, step N-3 (FIG. 4) is used as a criterion for determining whether or not a predetermined time has elapsed since the start of driving of the transport / stirring mechanisms 13 and 14. 6 is provided with a toner amount detecting means such as a toner amount detecting sensor 30 (FIG. 1), and the output of the toner amount detecting sensor 30 with respect to a predetermined toner amount is replaced with the transport / stirring mechanism driving time measuring means 47 (FIG. 3). It is also possible to provide a toner amount detection voltage measuring means for measuring the voltage and determine whether the toner amount has reached an image-formable state.
[0021]
In step N-5 (FIG. 4), the transfer / stirring mechanism drive time measurement control means 47 (FIG. 3) sets the predetermined time after the start of driving the transfer / stirring mechanisms 13 and 14 at the drive speed in the standardized mode. Determine if it has passed. In order to stabilize the charge amount of the toner, the predetermined time in this embodiment is 180 seconds, and when 180 seconds have elapsed, the process proceeds to step N-6 (FIG. 4), and the developing roller drive control means 46 (FIG. 3) The driving of the developing roller 16, the conveying / stirring mechanisms 13, 14 and the toner supply roller 26 is stopped by the conveyance / stirring mechanism drive control means 44 (FIG. 3) and the toner supply roller drive control means 45 (FIG. 3). In step N-7 (FIG. 4), the initialization mode ends.
When the initialization mode ends, the soft key display area of the "Developer initialization mode setting" on the operation liquid crystal panel returns from black to the original white display, and notifies the service person that the initialization mode has ended. .
[0022]
When the initialization mode ends and the "copy start button" on the operation unit of the image forming apparatus is pressed and an image forming signal is sent in step N-8 (FIG. 4), step N-9 (FIG. 4) In step N-10 (FIG. 4), the developing roller drive control means 46 (FIG. 3) and the transport / stirring mechanism drive control means 44 (FIG. 3) are automatically set to the standard mode by the mode switching means 41 (FIG. 3). The driving of the developing roller 16, the conveying / stirring mechanisms 13, 14 and the toner supply roller 26 is started by the toner supply roller drive control means 45 (FIG. 3). At this time, the driving speed of the developing roller 16 is set to 300 rpm in the standard mode, the toner supply roller 26 is driven intermittently, and a normal image forming operation is performed.
[0023]
【The invention's effect】
According to the image forming apparatus of the present invention, the time required until the developing device is filled with the toner and the image can be formed is reduced, and when the image forming device is newly installed or only the developing device is newly replaced. In addition, the installation time and replacement time can be significantly reduced, and a good image can be formed without overcharging the toner on the developing roller.
[0024]
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a main part of an image forming apparatus of the present invention.
FIG. 2 is a sectional plan view of a main part of a developing unit of the image forming apparatus shown in FIG.
FIG. 3 is a block diagram showing components related to toner supply control provided in the image forming apparatus of the present invention.
FIG. 4 is a flowchart illustrating toner supply control related to the image forming apparatus of the present invention.
[Explanation of symbols]
2: photosensitive drum 3: developing means 4: developing container 11: upstream transport path 12: downstream transport path 13: upstream transport / stirring mechanism 14: downstream transport / stirring mechanism 15: developer applying means 16: developing Roller 18: Toner regulating member 19: One-component toner 25: Toner container 26: Toner supply roller 27: Supply toner 28: Toner supply port 29: Toner drop port 30: Toner amount detection sensor 33: Corona charger 34: Exposure means 35: Sheet member (paper)
36: transfer roller 37: cleaning blade

Claims (5)

Image carrying means, electrostatic latent image forming means for forming an electrostatic latent image on the image carrying means, developing means for developing the electrostatic latent image on the image carrying means into a toner image, Transfer means for transferring the toner image on the image carrying means onto a sheet member,
The developing unit includes a developing container for storing toner, a developing application unit for applying the toner in the developing container onto the image bearing unit, and a conveying / stirring unit disposed in the developing container. Prepare
A circulation path including an upstream path and a downstream path extending in parallel in the width direction is defined in the developing container,
The upstream path and the downstream path are communicated with each other at both ends in the width direction,
The transport / stirring means includes an upstream transport / stirring mechanism disposed on the upstream path, and a downstream transport / stirring mechanism disposed on the downstream path.
An image forming apparatus, wherein the developing application unit includes a developing roller extending in a width direction along the downstream path, and applies the toner present in the downstream path to a peripheral surface of the developing roller to apply the toner to the image bearing unit. At
A toner replenishing port is provided above the upstream path, and a toner container that is removably attached to the developing container and stores replenished toner having a toner dropping port at a position facing the toner replenishing port. Prepare,
An initialization mode for replenishing toner from the toner storage container into the development container to enable image formation;
A mode switching control unit that switches between a standard mode for replenishing toner from the toner container to the developing container in a state where image formation is possible,
The toner supply amount in the initialization mode is set to be larger than the toner supply amount in the standard mode,
An image forming apparatus, wherein a driving speed of the developing roller in the initialization mode is set lower than a driving speed of the developing roller in the standard mode. 2. The image forming apparatus according to claim 1, wherein the drive of the developing roller is stopped in the initialization mode. 3. The device according to claim 1, wherein in the initialization mode, the drive speed of the developing roller is changed to be the same as the drive speed in the standard mode after a lapse of a predetermined time from the start of toner supply. Image forming device. A toner amount detecting unit is provided on the upstream side path. In the initialization mode, when the toner amount detecting unit detects a toner amount in a state where an image can be formed after toner supply is started, the developing roller 3. The image forming apparatus according to claim 1, wherein the driving speed is changed to the same as the driving speed in the standard mode. The image forming apparatus according to claim 1, wherein the developing unit is a one-component developing system.

Images