JP2001331076A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely recover residual toner and paper fiber, etc., at a cleaning station by preventing foreign matters, such as a mass of paper fiber, sticking to a photoreceptor drum from becoming bigger. SOLUTION: The image forming device scrapes sticking matters, which remain on the photoreceptor drum 1 after a transfer process, with a blade 3 of the cleaning station 25 and recovers them as waste toner. In the image forming device, a non-transfer process is executed in such a manner that a transfer operation is stopped at fixed intervals and a toner image 6 on the photoreceptor drum 1 is sent to the cleaning section 25 without being transferred. Thus a mass of paper fiber accumulating on the photoreceptor drum 1 is pushed and demolished with a relatively large amount of toner of the untransferred toner image and recovered without leakage from the cleaning station 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a copying machine or a printer for forming an image in an electrophotographic system.

[0002]

2. Description of the Related Art In an image forming apparatus for forming an image by an electrophotographic method, untransferred toner and the like remain on a photosensitive member after a transfer process. For this reason, in the conventional image forming apparatus, as shown in FIG. 4, the blade 103 is obliquely applied to the photosensitive drum 101 after the transfer process to scrape off the residual toner on the photosensitive drum 101 and remove the waste toner. And a cleaning unit 102 that conveys and collects to a collection unit (not shown) by a waste toner conveyance screw 104.

In order to remove such residual toner, for example, Japanese Patent Application Laid-Open No. 60-131585 discloses a method in which a blade that slides relatively to a photosensitive drum is provided, and a minute vibration is applied to the blade by a piezoelectric element. Discloses a configuration for effectively removing residual toner on a photosensitive drum.

[0004]

The toner image on the photoreceptor drum 101 is transferred to a sheet of paper having a polarity opposite to that of the toner image in the transfer step. It will be adsorbed on the body drum 101. Some of these paper dusts are scraped off by the blade 103, but the paper dusts 5 are different from fine particles like toner,
It is fibrous and has poor fluidity. Even if vibration is applied as in the above-mentioned known example, it is not scooped by the toner conveying screw 104 but is entangled with one another and deposited to form a paper dust lump 5.

When the paper dust mass 5 grows until it hits the toner receiving seal member 105 elastically slidably in contact with the photosensitive drum 101 in opposition to the blade 103, the tip side of the toner receiving seal member 105 is lifted, and There is a possibility that the paper dust lump 5 leaks out and scatters around to impair image formation.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problem. The object of the present invention is to suppress the growth of extraneous matter such as a lump of paper adhering to a photoreceptor drum and properly recover the toner in a cleaning unit. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

[0007]

The present invention has the following arrangement as means for solving the above-mentioned problems.

(1) In an image forming apparatus in which an adhering matter remaining on a photoreceptor after a transfer step in an electrophotographic image forming process is removed from the photoreceptor by a cleaning unit and then collected as waste toner, a predetermined process is performed. A control unit is provided for executing a non-transfer process that causes a toner image formed on a photoconductor to reach a cleaning unit without performing a transfer process.

In this configuration, the non-transfer process is periodically executed by the control unit, and the toner image of the processing image formed on the photoconductor arrives at the cleaning unit in an untransferred state. Therefore, even if there is a lump of paper in front of the blade of the cleaning unit, a relatively large amount of toner of the toner image gives an impressive pressing force to the lump of paper. For this reason, the paper dust lump is in a collapsed state, and is smoothly collected without leaking from the cleaning unit.

(2) The control unit executes the non-transfer process at the start of the image forming operation.

In this configuration, non-transfer processing is executed in a relatively short cycle for each image forming operation (image forming job). Therefore, a large amount of toner reaches the cleaning section before the paper dust attached to the photoreceptor grows as a lump centering on the larger piece, and the paper dust attached to the photoreceptor is dislodged by the pressing force of the large amount of toner. Is collected smoothly.

(3) The control unit executes a non-transfer process every time a sheet is fed.

In this configuration, the cycle in which the toner image arrives at the cleaning section in an untransferred state is further shortened, and paper dust and the like are effectively removed.

(4) The control unit receives a setting input of a printing rate in the processing image, and executes a non-transfer process using the processing image of the set printing rate.

In this configuration, the printing rate of the toner image to be transferred to the cleaning section in the untransferred state can be set arbitrarily by the user. For this reason, if the printing rate of the processing image is increased or decreased according to the characteristics of the paper to be used, for example, the generation of paper dust, the amount of collected toner is minimized, and the amount of toner consumption is reduced. Powder and the like are reliably eliminated.

(5) The control unit receives a setting input of an execution frequency of the non-transfer process, and executes the non-transfer process at the set execution frequency.

In this configuration, the user can arbitrarily set the execution interval and execution stop of the non-transfer process. Therefore, depending on the type of paper to be used, for example, depending on the occurrence of paper dust, by shortening the collection interval or stopping collection, the amount of collected toner can be minimized, and toner consumption can be reduced. The amount is saved.

(6) The control unit executes the non-transfer process when the load torque at the time of collecting the waste toner in the cleaning unit exceeds a predetermined value.

In this configuration, when the load torque of the waste toner transport mechanism in the cleaning unit exceeds a predetermined value, the control unit determines that the amount of accumulated paper dust on the photosensitive drum has increased, The toner image arrives at the cleaning unit in an untransferred state. For this reason, paper dust collection is executed at an appropriate timing, and the amount of toner is saved.

(7) When the frequency of execution of the non-transfer process exceeds a predetermined value, the control unit performs a warning display on the sheet in use.

In this configuration, if the frequency of execution of the non-transfer process increases, it is determined that the paper that generates a large amount of paper dust is used, and the user is notified by a warning to that effect that the toner consumption increases. recognize.

[0022]

FIG. 1 is a schematic sectional view showing the configuration of a copying machine which is an image forming apparatus according to an embodiment of the present invention. The copying machine M includes a scanner unit 10, an image forming unit 2,
0, a paper feeding unit 30, a paper discharging unit 40, and the like. The scanner section 10 includes a hard transparent glass platen 11 exposed above the copier body M1.
A scanner optical system 12 is provided below the scanner 1.
The scanner optical system 12 includes a light source 1 that irradiates light to a document image.
3. First to first reflected light from a document image in a predetermined direction
It comprises third mirrors 14 to 16, an imaging lens 17, and a CCD 18 as a photoelectric conversion element.

The scanner unit 10 includes a light source 24 and a mirror 1
4 to 16 are moved in parallel with the original table 11 on the lower surface of the original table 11, and the light of the light source 13 is irradiated on the entire image surface of the original placed on the upper surface of the original table 11. The reflected light of the light of the light source 13 on the original image surface is reflected by the mirrors 14 to 16 in order, and then is imaged on the light receiving surface of the CCD 18 by the imaging lens 17. The CCD 18 outputs an electric signal according to the amount of reflected light received on the light receiving surface.

The image forming unit 20 includes the photosensitive drum 1, a charger 21, a laser scanning unit (LSU) 22, a developing unit 23, a transfer roller 24, a cleaning unit 25, a fixing roller pair 26, and the like. The photosensitive drum 1 is formed by forming a photosensitive layer on the surface of a cylindrical conductive base made of aluminum or the like. Charger 21
Charges the surface of the photoreceptor drum 1 uniformly to a predetermined charge with a charge of a single polarity.

The LSU 22 includes a semiconductor laser 27 for emitting laser light, a polygon mirror 28, and mirrors 29 and 30.
After the A / D conversion of the output signal of the CCD 18 and the supply of image data that has been subjected to predetermined image processing, the photosensitive drum 1 is irradiated with a laser beam corresponding to the image data. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 1 by the photoconductive action. The developing device 23 supplies toner to the surface of the photosensitive drum 1 to visualize the electrostatic latent image into a toner image. The transfer roller 24 applies a predetermined transfer potential to the paper P supplied from the paper supply unit 30, and transfers the toner image carried on the surface of the photosensitive drum 1 to the surface of the paper P.

The paper feed section 30 is provided with a pickup roller 31, a paper feed detection sensor 32, and the like for feeding the paper P one by one. Pickup roller 31
Is fed between the photosensitive drum 1 and the transfer roller 24 at a timing synchronized with the rotation of the photosensitive drum 1 based on a detection signal from the feed detection sensor 32.

The sheet P after the transfer of the toner image is heated and pressed by the fixing roller pair 26, and the toner image is melted on the surface of the sheet P and is fixed firmly. Fixing roller 2
The paper P having passed through 6 is discharged to the outside of the copying machine M by the rotation of the discharge roller 42.

On the other hand, the surface of the photosensitive drum 1 after the transfer process is opposed to the cleaning unit 25, and the residual toner, paper dust and the like adhering to the surface of the photosensitive drum 1 are removed by the cleaning unit 25. The cleaning unit 25 is configured as shown in FIG.
As shown in the figure, the residual toner is collected in a predetermined collecting section (not shown).
A cleaning blade 3 that slides relative to the photosensitive drum 1 in an inclined posture from a direction opposite to the rotation direction of the photosensitive drum 1, and a tip of the blade 3 The photosensitive drum 1 is held by a frame 7 opposed to the
And a toner receiving seal member 4 that elastically contacts the toner receiving member. The toner receiving seal member 4 prevents residual toner, paper dust, and the like scraped off from the surface of the photosensitive drum 1 from leaking downstream in the rotation direction of the photosensitive drum 1.

FIG. 3 is a block diagram showing an electrical configuration of the copying machine. The control unit 50 includes a ROM 53 in which a processing program is written, and a RAM 54 for storing data.
It is configured by a CPU 51 having CPU5
1 includes a scanner unit 10, an image forming unit 20, a sheet feeding sensor 32, a sheet discharging sensor 41, a conveying screw 2 of a cleaning unit 25, a printing number counter 55, a printing rate setting unit 56, and a collection interval setting via a bus 54. Unit 56 and warning display unit 5
8 are connected. The CPU 51
In accordance with the processing program stored in the ROM 51, these input / output devices are generally controlled.

The control unit 50 controls the scanner unit 1 during the copying operation.
0, by controlling the operations of the image forming unit 20 and the paper feeding unit 30 to copy a copy of the image of the document and reading the document from the document on the surface of the photosensitive drum 1 at regular intervals, for example, printing Each time the count value of the number counter 55 exceeds a predetermined value, the transfer operation is stopped, and a toner image formed on the surface of the photosensitive drum 1 for a processing image having a solid black state or a printing rate of about 20% Is transferred to the blade 3 of the cleaning unit 25 in a state where it is not transferred to the sheet, and is transferred as it is.

In the above configuration, the residual toner not transferred to the paper P and the paper powder separated from the paper P adhere to the photosensitive drum 1 after the transfer process as described above. The residual toner and paper dust are scraped off from the surface of the photosensitive drum 1 by the blade 3 after passing through the toner receiving seal member 4 as the photosensitive drum 1 rotates. The residual toner scraped off from the surface of the photosensitive drum 1 accumulates on the upstream side of the blade 3 and is transported as waste toner by the waste toner transport screw 2 to the waste toner collecting section.

The paper dust accumulated in a portion that does not reach the waste toner conveying screw 2 is entangled with the fibers, and the paper dust lump 5
The toner receiving seal member 4 may be lifted up as it is. When the distal end of the toner receiving seal member 4 is lifted away from the surface of the photosensitive drum 1 in this manner, the residual toner and paper dust scraped off the surface of the photosensitive drum 1 cause the rotation direction of the photosensitive drum 1 to rotate. Can no longer be prevented from leaking downstream of
The inside of the copier body M1 and the paper P are soiled.

Therefore, the control unit 50 executes the non-transfer process every time the count value of the print number counter 55 exceeds a predetermined value, and performs the sheet feeding operation of the sheet P between the photosensitive drum 1 and the transfer unit 22. Once stopped, the photosensitive drum 1
A toner image 6 of a processing image is formed on the
The toner is guided to the cleaning unit 25 without being transferred to the surface of the photosensitive drum 1 by the blade 3. As a result, a larger amount of toner than the residual toner scraped off from the surface of the photosensitive drum 1 during the normal copying operation collides with the paper dust lump 5 that has been scraped off and grown by the blade 3.
Due to this collision, the paper dust mass 5 is broken and flows, and is pressed against the waste toner conveying screw 2. As a result, the paper dust mass 5 can be conveyed and collected by the waste toner conveyance screw 2 without providing a vibration mechanism or the like, so that the paper dust mass 5 is moved between the tip end side of the toner receiving seal member 4 and the photosensitive drum 1. It is prevented from leaking from and scattering around.

The number of print counts until the paper dust grows and lifts the toner receiving seal member 4 is usually on the order of thousands of sheets. If the toner image 6 in the untransferred state is collected every time the number reaches 1,000, the paper dust lump 5 can be collected well.

Incidentally, a piece of paper larger than the paper dust may be mixed in the paper P. If the piece of paper adheres and accumulates on the photosensitive drum 1, the toner is received before the predetermined count number is reached. There is a risk of hitting the seal member 4. Therefore, each time one copy operation constituted by an image forming operation on one or a plurality of sheets is completed, or each time the image forming operation on one sheet is completed, the control unit 50 executes a shorter cycle. A non-transfer process may be performed.

As a result, before the toner receiving seal member 4 prevents the leakage of residual toner and the like from leaking out earlier due to the entanglement of the scraps other than the paper dust and the like, the impact of the toner image 6 on the untransferred state is reduced. The toner can be pushed out to the waste toner conveying screw 2 by a proper pressing force and quickly collected.

The amount of paper dust varies depending on the type of paper P. For example, recycled paper tends to generate paper dust more easily than virgin paper. On the other hand, the amount of toner that collides with the paper mass 5 changes according to the printing rate of the processing image formed during the non-transfer process, and the collision force with the paper mass 5 changes.
Therefore, the execution frequency of the non-transfer process and the printing rate of the processing image should be adjusted according to the type of the paper P used for the copying operation, and the amount of toner consumed without being transferred to the paper should be reduced as much as possible. Therefore, a printing rate setting unit 56 and a collection interval setting unit 57 are provided in a part of the operation panel, and the paper P
Depending on the type, the user may arbitrarily set the execution cycle of the non-transfer process or the printing rate of the processing image within a predetermined range.

With this configuration, for example, when using paper P that generates little paper dust, the count value of the number-of-prints counter 55 is increased to reduce the execution frequency of the non-transfer process, or to print the image for processing. The rate can be reduced, and wasteful consumption of toner can be reduced while the paper powder 5 is reliably collected. In this case, the printing rate of the processing image is 20 to 100.
It is appropriate to be able to adjust in the range of%. The user may be allowed to cancel the execution of the non-transfer process when it is determined that the generation of paper dust is extremely small continuously.

On the other hand, when the paper P, which generates a lot of paper dust, is used, if the frequency of the non-transfer process is set to increase, the toner consumption increases and the running cost increases. . Therefore, when the execution frequency of the non-transfer process is higher than the set value, it is considered that the paper P in which paper dust is likely to be generated is used. Message may be displayed, or a lamp indicating a warning may be turned on.

When a large amount of paper dust accumulates in front of the blade 3 and the paper dust 5 reaches the waste toner conveying screw 2, the rotational load of the waste toner conveying screw 2 increases.
Therefore, the control unit 50 controls the waste toner conveying screw 2
If the non-transfer process is executed when the rotational load torque value is detected and the load torque value exceeds a preset load torque value, the rotational load of the toner conveying screw 2 in the paper dust mass 5 becomes excessive, Before the toner amount is excessively consumed, the paper dust 5 can be accurately removed at an appropriate timing.

[0041]

According to the present invention, the following effects can be obtained.

(1) A non-transfer process in which the transfer operation is stopped and the toner image on the photosensitive drum is transferred to the cleaning section in an untransferred state is executed, whereby the paper dust lump deposited on the photosensitive drum is executed. Can be destroyed with a relatively large amount of toner in the untransferred toner image. As a result, the paper dust lump can be satisfactorily collected with proper timing without leaking from the cleaning unit, and the inside of the apparatus and the paper can be prevented from being stained without adding a complicated mechanism.

(2) Each time one image forming operation is completed, the non-transfer process is executed, so that a piece of a piece larger than the paper dust adheres to the photosensitive drum, and the lump grows and stays. Previously, the toner image can be recovered and recovered by using the toner image in the untransferred state.

(3) By executing the non-transfer process each time one sheet of paper is fed, the cycle in which the toner image in the untransferred state reaches the cleaning section is further shortened, and the elimination of paper dust and the like is further improved. It can be performed reliably.

(4) By providing a print rate setting unit that can arbitrarily set the print rate of a processing image for forming a toner image during non-transfer processing, the print rate of the processing image can be set according to the type of paper used. Can be adjusted, and the amount of toner collected during the non-transfer process can be minimized to suppress waste of toner.

(5) By providing a collection interval setting section that can arbitrarily set the execution frequency of the non-transfer process, the execution frequency of the non-transfer process can be adjusted according to the type of paper used. Thus, the amount of toner collected can be minimized, and waste of toner can be suppressed.

(6) The non-transfer process is executed when the load torque of the waste toner conveying mechanism in the cleaning section exceeds a predetermined value, so that the collection of paper dust and the like can be executed at an accurate timing. And the amount of toner can be saved.

(7) By providing a warning display unit for displaying a warning about a sheet in use when the frequency of execution of the non-transfer process exceeds a predetermined value, for example, for a sheet that generates a lot of paper dust, During use, a warning is displayed to that effect, and the user can be surely recognized that toner consumption will increase.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a copying machine to which an image forming apparatus according to an embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram of an operation of a cleaning unit in the copying machine.

FIG. 3 is a block diagram showing a configuration of a control unit of the copying machine.

FIG. 4 is an explanatory diagram of a conventional cleaning unit.

[Explanation of symbols]

 Reference Signs List 1-Photoconductor drum 2-Waste toner transport mechanism 3-Cleaning blade 6-Untransferred toner image 25-Cleaning unit 50-Control unit 56-Print rate setting unit 57-Recovery interval setting unit 58-Warning display unit

Continued on the front page (72) Inventor Hideki Goto 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside (72) Inventor Yasuji Yamachi 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Sharp (72) Inventor Minoru Tomi Minoru 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka F-term (reference) 2H027 DA45 DA50 DA01 DB01 DC03 DC11 EC03 EC10 ED10 ED17 ED24 ED27 ED28 EE02 EF06 EF12 EK06 GA30 GA47 GB07 GB10 2H032 AA05 BA13 CA04 CA12 CA15 2H034 AA02 BF00 CA02

Claims (7)

[Claims] 1. An image forming apparatus for removing, from a photoreceptor, a deposit remaining on a photoreceptor after a transfer step in an electrophotographic image forming process, and recovering it as waste toner, a preset processing process An image forming apparatus comprising: a control unit that executes a non-transfer process that causes a toner image formed on a photoconductor of an image to reach a cleaning unit without performing a transfer process. 2. The image forming apparatus according to claim 1, wherein the control unit executes a non-transfer process at the start of an image forming operation. 3. The image forming apparatus according to claim 1, wherein the control unit executes a non-transfer process each time a sheet is fed. 4. The control unit according to claim 1, wherein the control unit receives a setting input of a printing ratio in the processing image and executes a non-transfer process using the processing image with the set printing ratio. Image forming apparatus. 5. The image forming apparatus according to claim 1, wherein the control unit receives a setting input of an execution frequency of the non-transfer process, and executes the non-transfer process at the set execution frequency. 6. The image forming apparatus according to claim 1, wherein the control unit executes a non-transfer process when a load torque at the time of collecting waste toner in a cleaning unit exceeds a predetermined value. 7. The image forming apparatus according to claim 6, wherein the control unit displays a warning about the sheet in use when the execution frequency of the non-transfer process exceeds a predetermined value.