JPH06110330A - Image forming device - Google Patents

Abstract

PURPOSE:To steadily carry out initial development when a toner supply part is replaced, in an image forming device provided with a development device which supplies one-component toner from the toner supply part to a development roller and develops an electrostatic latent image on an image carrier. CONSTITUTION:The image forming device which is provided with the development device for developing an electrostatic latent image on the image carrier 40 by supplying one-component toner in the toner supply part 56 to the development roller 50, a development device drive part 110 for driving the development device, a toner sensor 54a for detecting the presence/absence of toner in the development device, and mechanisms 59 and 19 for bringing the development device into contact with the image carrier 40 and separating it therefrom; and which, in the image formation, carries out development by the contact of the development roller 50 with the image carrier 40 is further provided with a control part 120 which, in response to the detection of an insufficiency of toner by the toner sensor 54a, drives the development device drive part 110 with the development roller 50 separated from the image carrier 40, supplies toner to the development roller 50, and then accepts an order to carry out image formation.

Description

Detailed Description of the Invention

(Table of Contents) Industrial Application Field of the Prior Art Problems to be Solved by the Invention Means for Solving the Problems (FIG. 1) Action Example (a) Description of Image Forming Apparatus (FIGS. 2 to 7) (b) Description of configuration of one embodiment (FIGS. 8 to 14) (c) Description of processing of one embodiment (FIGS. 15 to 16) (d) Description of another embodiment

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a developing device for replenishing a developing roller with a one-component toner from a toner replenishing portion to develop an electrostatic latent image on an image carrier.

In an image forming apparatus such as a copying machine, a printer or a facsimile machine, an electrophotographic apparatus or the like is used in order to record plain paper. The principle is that a photosensitive drum is charged, imagewise exposed and electrostatically charged. Form a latent image, develop with a developing device,
The process of transferring the toner image to the sheet and obtaining the toner image on the sheet is taken.

In such an image forming apparatus, a developing device using a one-component developer which can be inexpensively constructed and is easy to maintain is widely used, and one using a non-magnetic one-component toner is particularly used. Attention has been paid.

In the developing device using the non-magnetic one-component toner, the toner can be replenished by the toner replenishing device to continue the development, but it is advantageous in running cost to extend the replacement of the toner replenishing device as much as possible. Is.

[0006]

2. Description of the Related Art In a one-component developing device, a developing roller is brought into contact with a photosensitive drum, and toner carried by the developing roller is electrically moved to an electrostatic latent image on the photosensitive drum to perform development.

Since the developing roller comes into contact with the photosensitive drum, it is necessary that the developing roller has elasticity. The developing roller is retracted from the photosensitive drum except during printing to prevent plastic deformation of the developing roller. .

In such a one-component developing device, the toner can be replenished by the toner cassette, and the toner can be continuously replenished by exchanging the toner cassette. In a conventional image forming apparatus using such a developing device, printing is enabled at the same time as the toner cassette is replaced, a print command is accepted, and a printing operation including development by a developing roller is performed.

[0009]

However, the prior art has the following problems. In such a developing device, when toner in the toner cassette is exhausted, a method of issuing a toner cassette replacement instruction and urging the toner cassette to replace the toner cassette allows the developing device to have sufficient toner and printing about ten or more sheets. However, since it is disadvantageous in terms of running cost, it is desirable to adopt a method of issuing a toner cassette replacement instruction when the toner in the developing device is insufficient.

According to this method, if printing can be performed immediately after the replacement of the toner cassette as in the prior art, the amount of toner on the developing roller is insufficient even if the toner supply is started. The toner amount on the developing roller becomes non-uniform for a while, and the print image is disturbed at the start of printing.

Further, if the amount of toner on the developing roller becomes insufficient, the amount of sufficiently charged toner will decrease, and the printed image will be further disturbed at the start of printing. Therefore, it is an object of the present invention to provide an image forming apparatus capable of stably performing initial development when the toner replenishing section is replaced.

Another object of the present invention is to provide an image forming apparatus capable of accelerating the start time of image formation when the toner supply section is replaced.

[0013]

FIG. 1 shows the principle of the present invention. Claim 1 of the present invention provides an endless image carrier 4
0, the latent image forming portions 41 and 7 that form an electrostatic latent image on the image bearing member 40, and one component toner of the toner replenishing portion 56 to the developing roller 50 to electrostatically charge the image bearing member 40. Developing device 5 for developing a latent image, and developing device drive unit 11 for driving the developing device 5.
0, a toner sensor 54a for detecting the presence / absence of toner in the developing device 5, and separating / contacting mechanisms 59, 19 for separating / contacting the developing device 5 to / from the image carrier 40. In the image forming apparatus for developing by bringing the developing roller 50 of the developing device 5 into contact with the image carrier 40 by the contact mechanisms 59 and 19, the toner shortage is detected by the output of the toner sensor 54a. By the separating / connecting mechanism 59, 19,
With the developing roller 50 separated from the image carrier 40,
A control unit 120 is provided for driving the developing device driving unit 110 to supply toner to the developing roller 50 and then receiving an image forming command.

According to claim 2 of the present invention, in claim 1,
The controller 120 drives the developing device driver 110 at a higher speed than when an image is formed by the toner shortage output of the toner sensor 54a.

According to a third aspect of the present invention, in the first or second aspect, the control unit 120 stops the driving of the developing device driving unit 110 when the presence of toner is detected by the output of the toner sensor 54a. Then, the image forming command is received.

According to a fourth aspect of the present invention, in the first, second or third aspect, the control section 120 is the developing unit driving section 1.
Within a predetermined time from the start of driving 10, the toner sensor 5
Since the presence of toner is not detected by the output of 4a, the driving of the developing device driving unit 110 is stopped and the image forming command is accepted.

According to a fifth aspect of the present invention, in the fourth aspect,
The control unit 120 performs a toner shortage display by not detecting the presence of toner from the output of the toner sensor 54a within a predetermined time after the driving of the developing device drive unit 110 is started.

A sixth aspect of the present invention is the toner sensor 54a according to the first, second, third, fourth, or fifth aspect, in which the control unit 120 receives the toner sensor 54a after power-on or after receiving a replacement instruction of the toner replenishing unit 56. It is characterized in that the toner shortage is detected by the output of.

[0019]

According to the first aspect of the present invention, the control unit 120 detects the toner shortage from the output of the toner sensor 54a, so that the developing roller 50 is separated from the image carrier 40, and the toner replenishment unit 56 is operated. By driving the developing device drive unit 110 that drives the developing roller 50 to replenish the developing roller 50 with toner, the image forming command is accepted.
Until the developing roller 50 is sufficiently replenished with toner and the toner on the developing roller 50 becomes uniform, the acceptance of the image formation is prohibited so that the developing roller 5 can be formed before the image formation.
The toner of 0 can be made uniform, and stable image formation can be performed in the initial image formation.

In the second aspect of the present invention, the toner sensor 54
Due to the toner shortage output of a, the developing device driving unit 110 is driven at a higher speed than during image formation. Therefore, the toner is rapidly replenished to the developing roller 50 to make the toner on the developing roller 50 uniform at high speed, and wait for image formation. It saves time.

In the third aspect of the present invention, the toner sensor 54
When the presence of toner is detected by the output of a, the driving of the developing device drive unit 110 is stopped and the image forming command is accepted. Therefore, if the toner on the developing roller 50 becomes uniform, the image forming command is accepted immediately. Thus, the waiting time for image formation is shortened.

According to a fourth aspect of the present invention, the developing device driving section 11
Since the presence of toner is not detected by the output of the toner sensor 54a within a predetermined time from the start of driving 0,
Since the driving of the developing device driving unit 110 is stopped and the image forming command is accepted, the wasteful toner replenishing operation is not continued when the toner replenishing unit 56 is not replaced.

According to a fifth aspect of the present invention, the developing device drive section 11 is provided.
Since the presence of toner is not detected by the output of the toner sensor 54a within a predetermined time from the start of driving 0,
By displaying the toner shortage, it is detected that the toner replenishment portion 56 has not been replaced by the toner replenishment operation, and the toner replacement instruction is given.

According to the sixth aspect of the present invention, after the power is turned on or after the replacement instruction of the toner replenishing section 56 is received, the toner replenishing section 56 is replaced by detecting the toner shortage by the output of the toner sensor 54a. By executing the process when it is likely to be performed, the prohibition of acceptance of image formation is performed only when necessary.

[0025]

【Example】

(a) Description of Image Forming Apparatus FIG. 2 is an external view of an image forming apparatus of an embodiment of the present invention, FIG. 3 is a sectional view of an image forming apparatus of an embodiment of the present invention, and FIG. 4 is a process cartridge of an embodiment of the present invention. 5 is an explanatory view of an image forming apparatus according to an embodiment of the present invention, and FIGS. 6 and 7 are operation explanatory views (No. 1) and (No. 2) according to an embodiment of the present invention. The printer device is shown.

FIG. 2 is a perspective view of the apparatus as viewed from the front side of the apparatus, in which 10 is a front cover, which opens to the front to open the transport path 3, and 11 is an upper cover.
A device that covers the upper part of the device and opens the upper part of the device to open the upper part of the device; 12 is a paper feeding cassette, which is set from the front of the device; 13 is a paper feeding cassette insertion port; It is for.

Reference numeral 14 denotes a stacker, which is provided on the upper surface of the apparatus and accommodates printed paper, 15 is a paper guide, which guides the paper with the stacker 14, 16 is an operation panel, and various switches and A controller box 17 has a display section and accommodates a control circuit of the printer.

In the apparatus sectional view of FIG. 3, reference numeral 2 is a process cartridge, which is provided above the paper cassette 12 and will be described later with reference to FIG. 4, and 6 is a heat fixing device, which is a heat roller 60 and a backup roller. The heat roller 6 is used to fix the toner image on the sheet by sandwiching it between the heat roller 6 and the heat roller 6.
A cleaning roller 62 for removing the attached toner of 0 is provided.

Reference numeral 7 denotes an optical unit, which scans light of a semiconductor laser driven by image information with a polygon mirror, passes over the developing device 5 as shown by a dotted arrow in the figure, and passes through the photosensitive drum of the process cartridge 2. 40 is a unit for irradiating the sheet, and 8 is a sheet separating unit, which has a discharge electrode, discharges electric charges having a polarity opposite to the sheet back surface potential on the back side of the sheet after transfer, and neutralizes the back side of the sheet to remove the sheet. It is separated from the photosensitive drum 40.

Reference numeral 30 is a pickup roller for picking up the paper in the paper cassette 12, 31 is a registration roller for conveying the paper picked up by the pickup roller 30 with the leading ends thereof aligned, and 32 is a manual feed guide. , Which is opened to the right side of the drawing, guides the manually fed paper to the manual feed roller 33, and 33 is a manual feed roller which conveys the paper inserted from the manual feed guide 32 to the process cartridge 2.

Reference numeral 34 is a cover shaft, and the front cover 1
A discharge roller 36 serves as a rotation shaft of 0, and is for discharging the paper having passed through the thermal fixing device 6 to the stacker 14.

In the configuration diagram of the process cartridge of FIG. 4, the process cartridge 2 is composed of a drum cartridge 4 and a developing device 5, and the developing device 5 is attached to the drum cartridge 4 by a pin described later with reference to FIG. It is separated from the drum cartridge 4 by removing the pin.

Explaining the structure of the drum cartridge 4, reference numeral 40 denotes a photosensitive drum, which is formed by forming an organic photosensitive material layer (OPC or the like) on the surface of a cylindrical substrate such as aluminum, and rotates counterclockwise as shown in the drawing. What is done, 41
Is a charging roller, which is composed of a conductive rotating brush charger in which conductive rayon fiber is woven into a core metal and is planted, and uniformly charges the photosensitive drum 40 to about -600V.

A transfer roller 42 is provided on the drum cartridge 4 and is made of a conductive porous sponge material, for example, a porous polyurethane sponge material,
The photosensitive drum 40 is pressed against the photosensitive drum 40 and a transfer voltage is applied to transfer the toner image on the photosensitive drum 40 onto a sheet. Reference numeral 43 denotes a waste toner box (cleaner).
The residual toner of 0 is scraped by the scraping blade 44 and accommodated therein, and 45 is a grip, and the drum cartridge 4
And a roller cover 46 for protecting the transfer roller 42.

Next, the structure of the developing device 5 will be described.
Is a developing roller, which is made of a conductive elastic roller, preferably a conductive porous sponge material, for example, a conductive porous polyurethane foam sponge material, and rotates in a clockwise direction as shown in FIG. The component toner is held by its surface holding force and is conveyed to the photosensitive drum 40. The component toner is pressed against the photosensitive drum 40 so as to have a predetermined nip width, and a developing bias voltage of −300 V is applied. is there.

A layer thickness regulating blade portion 51 regulates the layer thickness of the toner adhering to the developing roller 50 to a predetermined thickness, and is composed of a stainless plate having a thickness of 0.1 mm. Is pressed to, for example, negative -400V
When the toner layer thickness is regulated, a negative charge is injected into the toner, and the toner is forcibly charged negatively to stably charge the toner even at high humidity and high temperature.

Reference numeral 52 denotes a reset roller, which is made of a conductive sponge material, is in contact with the developing roller 50, is rotated in the same direction as the developing roller 50, and is applied with a bias voltage of -400 V. To scrape off the toner from the developing roller 50 and to supply the toner to the developing roller 50 at the left side of the drawing.

Numerals 53 and 54 are paddle rollers, which rotate to agitate the non-magnetic one-component toner in the developing device 5 to charge it and convey it toward the reset roller 52, and 54a denotes a toner sensor. , A transmissive photosensor for detecting the presence or absence of toner agitated by the paddle roller 54, and 55 is a cassette housing portion,
It accommodates the toner cassette 56.

Reference numeral 56 denotes a toner cassette (toner replenishing section) for accommodating a one-component non-magnetic toner, and a cassette accommodating section 5
5, 57 is a toner supply lever, which is provided in the toner cassette 56 and rotates to supply the toner in the toner cassette 56 into the developing device 5. 58 is a grip. Yes, provided on the toner cassette 56 and used to hold the toner cassette 56 by hand, 5a is a paper guide rib, and the roller cover 4
Along with 6, the sheet is guided between the photosensitive drum 40 and the transfer roller 42.

The operation of this printer will be described with reference to FIGS. 2 to 4. The paper in the paper cassette 12 is picked up by the pickup roller 30, abutted against the registration roller 31, and the leading end of the registration roller 31 is aligned.
The character transfer path 3 is transferred in the direction of the photosensitive drum 40.

On the other hand, when the paper is picked up by the registration roller 31, the image exposure of the photosensitive drum 40 by the optical unit 7 is started, and the potential of the image exposure portion of the photosensitive drum 40 charged to −600 V by the charging roller 41. Becomes zero, and an electrostatic latent image corresponding to the image is formed.

In the developing device 5, the developing roller 50 is -40.
Since the bias voltage of 0V is applied, the negatively charged toner adheres to the image-exposed portion of the photosensitive drum 40 where the potential is zero, and a toner image is formed.

The toner image on the photosensitive drum 40 is transferred onto the sheet conveyed by the registration roller 31 and transferred onto the transfer roller 42.
Is transferred by electrostatic force and pressure by the photosensitive drum 4
The paper electrostatically attracted to 0 is separated from the photosensitive drum 40 by removing the potential on the back surface of the paper by the electric charge supplied to the paper separating unit 8.

The separated sheet is sent to the heat fixing device 6, the toner image on the sheet is heat fixed by the heat roller 60 of the heat fixing device 6, and is discharged to the stacker 14 by the discharging roller 36.

Similarly, the paper inserted by tilting the manual feed guide 32 is inserted by the manual feed roller 33 into the photosensitive drum 40.
The toner image on the photosensitive drum 40 is conveyed by the transfer roller 42 by the electrostatic force and pressure, and the sheet electrostatically attracted to the photosensitive drum 40 is charged by the sheet separating section 8 to the photosensitive drum. The toner image on the paper is thermally fixed by the heat roller 60 of the heat fixer 6 and discharged to the stacker 14 by the discharge roller 36.

5, the front cover 10 is opened to the front surface on the right side of the drawing around the cover shaft 34, and the front cover 10 has a manual feed guide 32 and a manual feed roller. 33 and the paper separating section 8
The heat fixing device 6 and the discharge (drive) roller 36a on the upper side of the discharge rollers 36 are provided.

Further, the upper cover 11 is opened at the upper part of the apparatus in the upper part of the drawing centering on a shaft (not shown), and among the discharging rollers 36, a lower discharging (pinch) roller 36b is provided.

Therefore, as shown in FIG. 6A, when the front cover 10 is opened, the U-shaped conveyance path 3 from the registration roller 31 to the discharge roller 36 is opened, which is convenient for removing jammed paper.

At this time, since the transfer roller 42 is provided on the process cartridge 2 side, the portion of the photosensitive drum 40 is not opened, but the transfer roller 42 is opposed (parallelism, position) to the photosensitive drum 40. If there is a misalignment, the transfer operation cannot be performed well, and therefore it is provided on the process cartridge 2 side. Even if this part is not opened, there is no problem in removing the jammed paper.

Similarly, the reason why the entire heat fixing device 6 is provided on the front cover 10 is that when the heat fixing device 6 is divided so that the conveying path can be opened, a part of the heat fixing device 6 is placed on the process cartridge 2. This is because it has to be installed in the process cartridge 2, which makes it inconvenient to take out the process cartridge 2. Even if this portion is not opened, there is no problem in removing the jammed paper.

In opening the cover, as shown in FIG. 3, the front cover 10 is opened so that the upper cover 11 is not opened unless the front cover 10 is opened.
Is disposed on the upper cover 11 at the discharging portion.

Therefore, as shown in FIG. 6 (B), when the front cover 10 is opened and the upper cover 11 is opened, as shown in FIG. With the process cartridge 2 installed from the front side, the toner cassette 56 can be easily taken out and attached, and only the toner cassette 56 can be replaced.

Further, as shown in FIG. 7, the front cover 1
Since the front side of the apparatus is opened by 0 and the upper side of the apparatus is opened by the upper cover 11, the process cartridge 2 can be easily taken out and attached.
Even if it is large, it is easy to replace.

For this reason, the process cartridge 2 can be made large, and the developing device 5 in the process cartridge 2 can be made large, so that the amount of developer accommodated can be increased and the replacement cycle can be greatly extended.

Also, by replacing only the toner cassette 56,
Since the developer can be replenished, the exchange period can be further extended. Further, the discharge roller 36 is separated and the cover 1
Since 0 and 11 are opened, the entire U-shaped transport path 3 can be opened and the jammed paper can be taken out more easily.

(B) Description of Configuration of One Embodiment FIG. 8 is an exploded configuration diagram of a process cartridge of one embodiment of the present invention, FIG. 9 is a united configuration diagram of a process cartridge of one embodiment of the present invention, and FIG. FIG. 11 is a cross-sectional view of an embodiment separation / contact mechanism of the present invention, FIG. 12 is a front view of the embodiment separation / contact mechanism of the present invention, and FIG. It is a block diagram of an Example separation / contact mechanism.

As shown in FIG. 8, the drum cartridge 4
Then, on the upper part of the unit frame 47, the photosensitive drum 40
A charging roller 41, a transfer roller 42, a waste toner box 43, a roller cover 46, an engagement pin 49 for separating and contacting the developing device 5, and an abutment for a pressing spring of the developing device 5. An abutting portion 470 is provided, a lower portion serves as a housing portion for the developing device 5, and a fulcrum hole 48 into which the locking pin P shown in FIG. 10 is inserted is provided at the center of the unit frame 47.

On the other hand, the developing device 5 includes a developing device frame 50.
A fitting hole 501 into which the locking pin P is fitted is provided in the center of 0, and a pressing spring (coil spring) 512 is provided on the left side of the fitting hole 501.

The blade portion 51 of the developing device 5 has a blade main body 510 supported by an L-shaped blade holder 511, which is rotatable about a rotation shaft 512 and a leaf spring 513. The blade body 510 is pressed against the developing roller 50 by pressing one end of the blade holder 511.

Further, the developing device 5 is provided with a movable retracting lever 510. The developing device 5 is inserted into the drum cartridge 4 from the lower side of the drum cartridge 4, and the fitting hole 501 of the developing device 5 and the drum cartridge 4 are inserted.
Align with the fulcrum hole 48 of, and as shown in FIG.
When the locking pin P is inserted into the fulcrum hole 48 of the drum cartridge 4 from both sides, the locking pin P penetrates the fulcrum hole 48 and is fitted into the fitting hole 501 of the developing device 5, and the locking pin P is Locked to the unit frame 47 of the fulcrum hole 48,
To unite.

As a result, as shown in FIG.
Are housed in the drum cartridge 4, mounted, and united. At this time, the developing device 5 becomes rotatable about the locking pin P as a fulcrum by fitting the locking pin P into the fitting hole 501, and the pressing spring 502 abuts against the abutting portion 470 of the drum cartridge 4. , The counterclockwise rotation moment in FIG. 9 is applied, and the developing roller 50 can be pressed against the photosensitive drum 40.

Therefore, by aligning the fitting hole 501 of the developing device 5 with the fulcrum hole 48 of the drum cartridge 4,
The developing roller 50 and the photosensitive drum 40 can be aligned with each other, and the alignment mechanism is unnecessary.

On the other hand, from the drum cartridge 4 to the developing device 5
To remove the lock pin P, the lock pin P is released from the fulcrum hole 48 of the unit frame 47 of the drum cartridge 4 and the lock pin P is pulled out as shown by the arrow in FIG. Then, the drum cartridge 4 and the developing device 5 are separated.

As described above, since the drum cartridge 4 and the developing device 5 can be combined and separated, the drum cartridge 4 with the developing device 5 can be held by the handle 45, removed from the apparatus, and attached to the apparatus.

Thus, in order to replace only the developing device 5, the drum cartridge 4 is pulled out from the apparatus and the locking pin P is pulled out to separate the developing device 5 from the drum cartridge 4 and to replace the new developing device 5. Drum cartridge 4
The locking pin P may be inserted into and attached to and the drum cartridge 4 may be set in the apparatus.

Even when only the drum cartridge 4 is replaced, the developing device 5 is separated from the drum cartridge 4 by pulling out the drum cartridge 4 from the apparatus and pulling out the locking pin P, and a new drum is added to the developing device 5. The cartridge 4 may be inserted by inserting the locking pin P, and the drum cartridge 4 may be set in the apparatus.

Similarly, the drum cartridge 4 and the developing device 5
To replace both of them, the drum cartridge 4 incorporating the developing device 5 may be removed from the apparatus, and the drum cartridge 4 incorporating the new developing device 5 may be set in the apparatus.

Therefore, in any case, the drum cartridge 4 need only be attached to and detached from the apparatus once, and the replacement work is facilitated and even if the drum cartridge 4 can be separated, the developing device 5 and the photosensitive drum 40 can be separated from each other. Alignment becomes unnecessary.

Next, the separating / contacting mechanism of the developing device 5 will be described with reference to FIGS. 11, 12, and 13. 11 and 1
2, the tip of the evacuation lever 590 has a protruding portion 59.
0a is formed and engages with the engaging pin 49 provided on the frame 47 of the drum cartridge 4, the developing device 5 is rotated clockwise in the drawing, and the developing roller 50 is separated from the photosensitive drum 40.

A return spring 593 is provided at the rear end of the retract lever 590 and is connected to the frame 500 of the developing device 5. Normally, as shown in the figure, the retract spring 593 causes the retract lever 590 to protrude. The portion 590a is in the retracted position in which the developing roller 50 is separated from the photosensitive drum 40 by engaging with the engaging pin 49 provided on the frame 47 of the drum cartridge 4.

A spur gear 591 is formed in the central portion of the retract lever 590, meshes with the gear 595b of the blade retract member 595, and a rear portion is provided with a pressing portion 592 that is pushed by the drive mechanism 19 described later. It is supported by being sandwiched between the gear 595b of the blade retracting member 595 and the guide roller 594 at the center.

The blade retracting member 595 is a spur gear 591.
A lever 595a is provided on a gear 595b that meshes with the lever 595a.
13 is engaged.

In the retracted state of FIG. 11, the lever 595a is directed sideways, and the leaf spring 513 is loosely pressed, so that the leaf spring 5 is released.
The pressure contact force of the blade main body 510 to the developing roller 50 by 13 is reduced.

In FIG. 13, a drive mechanism 19 provided on the apparatus side includes a separation / connection motor 100, a motor gear 102 provided on the shaft of the separation / connection motor 100, and a motor gear 102.
A drive gear 103 that meshes with the drive gear 103, a gear 104 that is provided coaxially with the drive gear 103, a drive lever 105 that is rotatable about a rotation shaft 105, and a half-moon shape that is provided at the lower end of the drive lever 105 and that meshes with the gear 104. Tooth 106 and a recovery spring 108 that urges the drive lever 105 in a clockwise direction about the rotation shaft 107.

The operation of this separating / connecting mechanism will be described with reference to FIG.
In the retracted state of the motor 10, as shown in FIG.
When 0 is rotated in the counterclockwise direction, the gear 104 rotates clockwise through the gears 102 and 103, and the engagement with the teeth 106 of the drive lever 105 causes the drive lever 105 to move to the recovery spring 108 about the rotation shaft 107. It counterclockwise rotates.

By this rotation of the drive lever 105, the pushing portion 592 at the rear end of the retract lever 590 is pushed to move the retract lever 590 rightward in FIG.
The engagement between the protruding portion 590a and the engaging pin 49 of the drum cartridge 4 is released.

As a result, the developing device 5 is provided with a rotational moment about the fitting hole 501 by the pressing spring 502 (see FIG. 11), and the developing roller 50 is pressed against the photosensitive drum 40 and brought into contact with it.

At the same time, the movement of the spur gear 591 of the drive lever 590 causes the gear 5 of the blade retracting member 595 to move.
95b rotates clockwise, and as shown in FIG. 13, the lever 595a is oriented vertically, the leaf spring 513 is pressed, and the pressing force of the blade main body 510 to the developing roller 50 is strengthened, so that the toner can be regulated.

On the contrary, the motor 100 is used to return to the retracted state.
To rotate the gear 104 in the counterclockwise direction via the gears 102 and 103 to rotate the teeth 1 of the drive lever 105.
The drive lever 105 is engaged with the rotary shaft 1 by engaging with 06.
It rotates clockwise about 07.

By the rotation of the drive lever 105, the pressing of the pressing portion 592 at the rear end of the retract lever 590 is released,
The return spring 593 moves the retreat lever 590 to the left in FIG. 13, and the protruding portion 590 a of the retreat lever 590 is moved.
And the engagement pin 49 of the drum cartridge 4 is engaged.

As a result, the developing device 5 rotates counterclockwise around the fitting hole 501, and the developing roller 50 separates from the photosensitive drum 40 and is in a retracted state. With this,
By the movement of the spur gear 591 of the drive lever 590, the gear 595b of the blade retracting member 595 rotates counterclockwise, and as shown in FIG. 11, the lever 595a is turned sideways and the leaf spring 513 is released and the blade main body is released. 51
The pressure contact force of the developing roller 50 of 0 to the developing roller 50 is weakened,
It enables high speed rotation.

In such a separating / contacting mechanism, the developing roller 50
Since the pressure contact force of the blade main body 510 is released when the blade is retracted, the developing roller 50 can be prevented from being plastically deformed and rotated at a high speed at the retracted position.

When the power is turned off and the rotational driving force of the motor 100 is lost in the contact state, the recovery spring 108 forcibly rotates the drive lever 105 in the clockwise direction to set the retracted state. can do.

FIG. 14 is a block diagram of an embodiment of the present invention. In the figure, reference numeral 120 denotes a control unit, which is composed of a microprocessor, receives a print command, drives a drum motor (not shown) that drives the photosensitive drum 40 and the like, and receives and outputs the toner sensor 54a. A motor 100 and a developing motor 110 are drive-controlled, and 110 is a developing motor, which drives the developing device 5. In the developing device 5, the developing roller 50, the reset roller 52, the paddle roller 53, 54, the supply lever 57 of the toner cassette 56 is rotated synchronously.

Reference numeral 121 denotes a motor driver which operates the developing motor 110 in response to a command from the control unit 120.
0 is rotationally driven, and 122 is a timer, which provides time information for the control unit 120.

(C) Description of Processing of One Embodiment FIGS. 15 and 16 are processing flow diagrams (No. 1) and (No. 2) of an embodiment of the present invention.

The pre-printing process will be described with reference to FIG. The control unit (hereinafter referred to as a processor) 120 receives the toner replenishment command from the operation panel (see FIG. 2) 16 at the time of initialization when the power is turned on or after the toner cassette 56 is replaced, and the toner sensor 54a of the developing device 5 is received. Is read to determine whether the toner is at the position of the paddle roller 54 of the developing device 5.

When the processor 120 determines that there is toner, it proceeds to the print command waiting state of step. On the other hand, when the processor 120 determines that there is no toner, it issues a high-speed command to the motor driver 121 to speed up the developing motor 110 (for example, 1.2 times the speed at normal times).
To rotate the timer 122 and start the timer 122.

At this time, the developing device 5 is in the retracted position as described with reference to FIG. 16, and the developing roller 50, the reset roller 52, the paddle rollers 53 and 54, and the supply lever 57 are
If the toner cassette 56 contains toner in the high speed rotation, the toner is charged at high speed and is supplied to the developing roller 50.

The processor 120 reads the output of the toner sensor 54a of the developing unit 5 and determines whether the toner is at the position of the paddle roller 54 of the developing unit 5. When the processor 120 determines that the toner is at the position of the paddle roller 54 of the developing device 5, a part of the toner will be part of the developing roller 50.
And it is determined that the toner on the developing roller 50 has become uniform, and the process proceeds to step.

On the other hand, if the processor 120 determines that the toner is at the position of the paddle roller 54 of the developing device 5,
It is determined whether or not the timer 122 has timed out (60-second time count output), and if there is no time-out output, the process returns to the step.

On the contrary, if there is a time-out output, the toner is not replenished even if it is driven for 60 seconds.
Displays toner low (insufficient toner) on the operation panel 16 and proceeds to step.

The processor 120 uses the motor driver 1
21 is instructed to turn off the motor, the developing motor 110 is stopped, and the process proceeds to step. The processor 120 waits for a print command from the host.

Next, the print command processing will be described with reference to FIG. When the processor 120 receives a print command from the host,
By driving the separation / contact motor 100 in the contact direction, the developing device 5 is moved to the contact position, the developing roller 50 is brought into contact with the photosensitive drum 40, and the blade main body 510 is pressed as shown in FIGS. Strengthen.

Next, the processor 120 determines the developing motor 1
10 is driven at a constant speed via the motor driver 121. At this time, at the same time, the drum motor of the photosensitive drum 40 (not shown) is also driven.

The processor 120 reads the output of the toner sensor 54a of the developing unit 5 and determines whether the toner is at the position of the paddle roller 54 of the developing unit 5. When the processor 120 determines that the toner is not at the position of the paddle roller 54 of the developing unit 5, it displays a toner low (insufficient toner) on the operation panel 16, and proceeds to step, where the toner is at the position of the paddle roller 54 of the developing unit 5. If there is,
Since there is no toner shortage, the process proceeds to step.

Even when the toner is in short supply, it is possible to print several sheets, and it is not necessary to stop printing. The processor 120 drives the optical unit 7 according to the print data following the print command, writes the image on the photosensitive drum 40, develops the image with the developing device 5, and transfers the image onto the sheet with the transfer roller 4.
A series of printing operations of transferring with 2 and fixing with the thermal fixing device 6 are performed, and when the printing is completed, the developing motor 110 is stopped via the motor driver 121, the drum motor is also stopped, and the separation / contact motor 100 is retracted. 11 to 13, the developing device 5 is moved to the retracted position, the developing roller 50 is separated from the photosensitive drum 40, and the pressure contact force of the blade main body 510 is weakened. Return.

When the toner cassette 56 is replaced in this manner, the developing device 5 is driven at high speed to supply the toner in the toner cassette 56 to the developing roller 50,
Since the toner of 0 is made uniform and waiting for the print command to receive the print command, stable development is possible from the initial stage.

Further, since the developing device 5 is driven at high speed, the toner is transferred from the cassette 56 to the developing roller 50 at high speed even if the developing device 5 is enlarged in order to increase the amount of developer accommodated and the toner path is lengthened. It is moved and charged, and the time until waiting for a print command is not lengthened.

Further, when the toner reaches a predetermined position, the driving of the developing device 5 is stopped and the print command is waited, so that the time until the print command is waited is not lengthened. (d) Description of Other Embodiments In addition to the above embodiments, the present invention can be modified as follows.

The sheet PP is not limited to paper, and other media can be used. Although the image forming apparatus is described as a printer, it may be another image forming apparatus such as a copying machine or a facsimile.

Although the separating / connecting mechanism has been described with reference to FIGS. 11 to 13, other structures may be used. The photosensitive member is not limited to the drum shape, and may have other endless shapes such as an endless belt shape.
Not limited to the charging roller, a corotron or the like may be used.

The present invention has been described above with reference to the embodiments.
Various modifications are possible within the scope of the invention, and these modifications are not excluded from the scope of the invention.

[0104]

As described above, according to the present invention,
It has the following effects. When the lack of toner is detected, the developing device is driven to form a uniform toner layer on the developing roller and then the development is started, so that stable development can be performed from the initial stage.

Further, since the toner shortage can be detected by the state of the toner in the developing device, the replacement cycle of the toner replenishing portion can be extended and the running cost can be reduced.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is an external view of an image forming apparatus according to an embodiment of the present invention.

FIG. 3 is a sectional view of an image forming apparatus according to an embodiment of the present invention.

FIG. 4 is a configuration diagram of a process cartridge according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram of an image forming apparatus according to an embodiment of the present invention.

FIG. 6 is an operation explanatory view (No. 1) of the image forming apparatus according to the embodiment of the present invention.

FIG. 7 is an operation explanatory view (No. 2) of the image forming apparatus according to the embodiment of the present invention.

FIG. 8 is an exploded configuration diagram of a process cartridge according to an embodiment of the present invention.

FIG. 9 is a schematic view of a combined process cartridge according to the embodiment of the present invention.

FIG. 10 is an explanatory view of a process cartridge according to an embodiment of the present invention, which is incorporated.

FIG. 11 is a sectional view of the separating / connecting mechanism according to the embodiment of the present invention.

FIG. 12 is a front view of a separating / connecting mechanism according to an embodiment of the present invention.

FIG. 13 is a configuration diagram of a separating / connecting mechanism according to an embodiment of the present invention.

FIG. 14 is a block diagram of an embodiment of the present invention.

FIG. 15 is a processing flowchart (1) of the embodiment of the present invention.

FIG. 16 is a processing flowchart (2) of the embodiment of the present invention.

[Explanation of Codes] 2 Process Cartridge 4 Drum Cartridge 5 Developing Device 7 Optical Unit 19 Driving Mechanism 40 Photosensitive Drum 41 Charging Roller 42 Transfer Roller 48 Support Point Hole 49 Engaging Pin 50 Developing Roller 54a Toner Sensor 56 Toner Cassette 59 Separation Mechanism 100 Separation motor 110 Development motor 120 Control unit 501 Fitting hole 502 Pressing spring P Locking pin

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G03G 15/00 301

Claims (6)

[Claims] 1. An endless image carrier (40) and a latent image forming section (4) for forming an electrostatic latent image on the image carrier (40).
1, 7), a developing device (5) for developing the electrostatic latent image on the image carrier (40) by replenishing the developing roller (50) with one-component toner of the toner replenishing section (56), and the developing device (5). A developing device driving section (110) for driving the developing device (5), a toner sensor (54a) for detecting the presence or absence of toner in the developing device (5), and the developing device (5) for the image carrier (40). ) And a separating / contacting mechanism (59, 19) for separating and contacting the developing roller (50) of the developing device (5) by the separating / contacting mechanism (59, 19) during image formation. 40), in the image forming apparatus for developing, when the toner shortage is detected by the output of the toner sensor (54a), the developing roller (50) is moved by the separating / contacting mechanism (59, 19). The developing device drive section (110) is driven in a state of being separated from the image carrier (40), and An image forming apparatus comprising a control unit (120) for receiving an image forming command after replenishing toner to the image roller (50). 2. The control unit (120) drives the developing device drive unit (110) at a higher speed than when an image is formed by the toner shortage output of the toner sensor (54a). Image forming device. 3. The control unit (120) stops the driving of the developing device driving unit (110) by detecting the presence of toner from the output of the toner sensor (54a), and issues an image forming command. The image forming apparatus according to claim 1, wherein the image forming apparatus receives the image. 4. The control unit (120) does not detect the presence of toner by the output of the toner sensor (54a) within a predetermined time after the driving of the developing device drive unit (110) is started, The image forming apparatus according to claim 1, wherein the driving of the developing device driving unit (110) is stopped to receive an image forming command. 5. The control unit (120) does not detect the presence of toner by the output of the toner sensor (54a) within a predetermined time from the start of driving the developing device drive unit (110), The image forming apparatus according to claim 4, wherein the toner shortage is displayed. 6. The control unit (120) detects shortage of toner by the output of the toner sensor (54a) after power-on or after receiving a replacement instruction of the toner replenishing unit (56). The image forming apparatus according to claim 1, 2 or 3 or 4 or 5.