JP2004341221A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus by which installation time and replacement time are remarkably shortened in the case of newly installing the image forming apparatus and in the case of newly replacing only a developing device by shortening time required for filling toner more as compared with a conventional manner. <P>SOLUTION: The image forming apparatus incorporates a mode changeover control means to switch an initialization mode in which image forming is made feasible by replenishing 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 forming feasible state, and a developing roller 16 is stopped in the initialization mode, and the rotating/driving directions of feeding/stirring mechanisms 13 and 14 in the initialization mode are set reverse to those of them 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, according to the control described in the above publication, the time for replenishing the toner from the hopper into the developing device can be reduced, but the time for reaching the developing roller inside the developing device is not reduced so much. It was difficult to increase the speed.
Particularly, in the case of a developing device having two toner transport paths in a direction parallel to the developing roller, the toner supplied to the upstream transport path distant from the developing roller moves to the downstream transport path next to the developing roller and is transferred to the developing roller. It took a long time to reach.
[0007]
An object of the present invention is to solve the above problems, further reduce the time required for toner filling, and significantly reduce the installation time and replacement time when newly installing an image forming apparatus or replacing only a developing device. To provide an improved image forming apparatus.
[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 rotational drive direction of the transport and stirring mechanism in the initialization mode, and wherein the set in the rotary drive direction opposite the conveying and stirring mechanism of the standard mode.
[0009]
[Operation of the present invention]
According to the present invention, in the so-called initialization mode in which only the image forming apparatus or the developing device is newly installed, the rotational drive direction of the transport / stirring mechanism is changed to the transport / stirring in the standard mode in which image formation is repeatedly performed. It is set in the direction opposite to the rotational drive direction of the mechanism.
[0010]
More specifically, referring to FIG. 2, the toner supplied from the toner supply port 28 (arranged between the lines A and B) indicated by reference numeral 28 in FIG. In the standard mode, the actuator moves in the directions of arrows 20 and 21 in FIG. 2B, and in the initialization mode, moves in the direction of arrow 50 in FIG. 2A. The replenished toner moves directly to the developing roller 16 side.
That is, when the toner supply port 28 is disposed between the lines A and B in FIG. 2, the transport toner moves in the directions indicated by arrows 20 and 21 shown in FIG. In the case of moving in the direction of the arrow 50 shown in FIG. 2A, the moving distance of the transported toner until reaching the developing roller 16 can be set shorter, and the time until reaching the vicinity of the developing roller 16 is reduced.
Also, as can be easily inferred from FIG. 2, when the toner supply port 28 is disposed at one end in the width direction of the upstream path (near line B), the moving distance of the transported toner until it reaches the developing roller 16. Is the shortest, and the time to reach the vicinity of the developing roller 16 is also the shortest.
[0011]
【Example】
The present invention is suitably used in an image forming apparatus having one-component developing means. However, as described above, even if the moving distance of the toner is short, for example, by improving the structure of the stirring mechanism, it is possible to efficiently mix and stir the carrier and the toner, and to start up to a charge amount capable of forming an image in a short time. The present invention is also applicable to a two-component developing system.
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.
[0012]
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.
[0013]
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.
[0014]
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.
The repetition of image formation consumes the one-component toner 19, and replenishes the toner container 25 from the toner container 25 which is detachably installed in the developing container 4 by rotating the toner replenishing roller 26 serving as a toner replenishing means. The toner 27 is supplied. A toner replenishing port 28 is formed on the upstream path 11 side of the upper wall 9 of the toner developing container 4, and a toner dropping port 29 is formed on the toner container 25 at a position facing the toner replenishing port 28. Is supplied from the toner drop port 29 to the upstream path 11 through the toner supply port 28.
In this embodiment, the toner supply port 28 is formed at one end of the upper wall 9 in the width direction of the upstream path 11. If it is between them, it can be formed at any position (between the line A and the line B in FIG. 2A).
[0015]
The developing container 4 contains a one-component toner 19. According to the present invention, the rotational drive direction of the transport / stirring mechanisms 13 and 14 in the initialization mode (when newly installing the image forming apparatus and the developing device) is changed to the transport / stirring in the standard mode (during normal image formation). It is characterized in that it is set in a direction opposite to the rotational drive direction of the mechanisms 13 and 14.
In the standard mode, as shown in FIG. 2B, the one-component toner 19 flows through the upstream path 11 at one end as indicated by an arrow 20 while being stirred by the action of the upstream transport / stirring mechanism 13. From the other end of the upstream path 11 to the other end of the downstream path 12 as indicated by an arrow 21. 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 route to one end of the upstream route 11. Thus, the one-component toner 19 circulates through the upstream path 11 and the downstream path 12.
[0016]
On the other hand, in the initialization mode, the rotational driving directions of the transport / stirring mechanisms 13 and 14 are set to be opposite to the rotational driving directions of the transporting / stirring mechanisms 13 and 14 in the standard mode. For this reason, as shown in FIG. 2A, the toner supplied to the upstream path 11 through the toner supply port 28 is stirred by the action of the conveying / stirring mechanisms 13 and 14 while the arrows 50 and 51 are being stirred. , 52, and 53, the toner supplied from the toner supply port 28 moves directly to the developing roller 16 side, and can reach the vicinity of the developing roller 16 in a very short time. .
At this time, as described above, when the toner supply port 28 is located between the line A and the line B, the rotation driving direction of the conveying / stirring mechanisms 13 and 14 is set to be opposite to that in the standard mode. Since the movement distance of the supplied toner from the toner supply port 28 to the developing roller 16 is reduced, the time required for the supplied toner to reach the vicinity of the developing roller 16 is also reduced.
[0017]
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.
In addition, the direction of rotation of the transport / stirring mechanisms 13 and 14 is changed (control means 44a), the driving of the transport / stirring mechanisms 13 and 14 is started or stopped (control means 44b), and the transport / stirring mechanism is controlled. It is characterized by having a drive control means 44.
As described above, the initialization mode 42 is a mode in which the toner is supplied into the developing container 4 when the image forming apparatus is newly installed or when only the developing apparatus is replaced due to a failure of the developing apparatus. This is a mode in which image formation is enabled. The standard mode 43 is a mode in which toner is replenished when toner in the developing container 4 is consumed due to repetition of image formation.
[0018]
The toner supply control method of the image forming apparatus according to 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 mechanisms 13 and 14 are driven and the toner supply roller 26 is driven by the transport / stirring mechanism drive control unit 44 (FIG. 3) and the toner supply roller drive control unit 45 (FIG. 3). Is started. At this time, the rotational drive direction of the transport / stirring mechanisms 13 and 14 is set by the transport / stirring mechanism drive control means 44 (FIG. 3) to be opposite to the rotational drive direction in the standard mode.
Further, by continuously driving the toner replenishing roller 26 as described above, more toner is replenished, and the rotational driving direction of the transport / stirring mechanisms 13 and 14 is set to be opposite to the rotational driving direction in the standard mode. This further reduces the toner filling time.
[0019]
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), where the transport / stirring mechanism 13 is controlled by the transport / stirring mechanism drive control unit 44 (FIG. 3). The rotation driving direction of the toner supply roller 14 is changed to the same as the rotation driving direction in the standardization mode, and the toner supply roller 26 which has been continuously driven by the toner supply roller drive control means 45 (FIG. 3) is intermittently driven to reduce the toner conveyance amount. Try to keep it 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 density sensor 30 for 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 to determine whether or not the toner amount has reached an image-formable state.
[0020]
In step N-5 (FIG. 4), the transport / stirring mechanism driving time measurement control means 47 (FIG. 3) controls the transport / stirring mechanism 13 and 14 in the rotational drive direction in the standardization mode for a predetermined time from the start of driving. To determine if has elapsed. 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 transport / stirring mechanism drive control means 44 ( 3), the driving of the conveying / stirring mechanisms 13, 14 and the toner supply roller 26 is stopped by the toner supply roller drive control means 45 (FIG. 3), and the initialization mode ends in step N-7 (FIG. 4). .
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. .
[0021]
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) The mode is automatically set to the standard mode by the mode switching means 41 (FIG. 3) at step N-10. At step N-10 (FIG. 4), the transport / stirring mechanism drive control means 44 (FIG. 3) and the toner supply roller drive control means 45 ( 3), the driving of the conveying / stirring mechanisms 13, 14 and the toner supply roller 26 is started. The toner supply roller 26 is driven intermittently to perform a normal image forming operation.
[0022]
【The invention's effect】
According to the image forming apparatus of the present invention, the time required for filling the toner is further reduced as compared with the related art, and when the image forming apparatus is newly installed or only the developing device is newly replaced, the installation time and the replacement time are reduced. Can be significantly reduced.
[0023]
[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 density sensor 33: Corona charger 34: Exposure means 35 : Sheet material (paper)
36: transfer roller 37: cleaning blade

Claims (2)

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,
An image forming apparatus, wherein a rotation drive direction of the transport / stirring mechanism in the initialization mode is set to be opposite to a rotational drive direction of the transport / stirring mechanism in the standard mode. 2. The image forming apparatus according to claim 1, wherein said developing unit is a one-component developing system.

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