JP2002311771A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of maintaining excellent cleaning performance over a long term by changing the cleaning interval of a cleaning blade in consideration of the number of image forming sheets and an environmental condition such as temperature and humidity, in the image forming device constituted so that a foreign matter such as paper dust adhering to the edge of the cleaning body is removed by reversely rotating a photoreceptor. SOLUTION: This image forming device is equipped with a controller 39 performing the cleaning of the cleaning blade by rotating the photoreceptor in the reverse direction to that at the time of forming an image, and a blade cleaning counter 40 for setting the cleaning interval of the blade based on the number of image forming sheets. In the device, the set value of the counter 40 is alternatively selected and the photoreceptor is reversely rotated so that the blade may be cleaned every time the number of image forming sheets reaches a set value, and the interval that the blade is cleaned is selected in accordance with the number of image forming sheets.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a copying machine and a printer.
The present invention relates to an electrophotographic image forming apparatus such as a facsimile apparatus, and more particularly, to an improved cleaning method of a cleaning blade provided for cleaning a photosensitive member.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus,
An electrostatic latent image formed by irradiating optical image information such as reflected light of a document on the surface of a photoreceptor uniformly charged in advance is developed with a toner supplied from a developing device to form a toner image. An image is formed by transferring and fixing an image on transfer paper. Since foreign matter such as residual toner and paper dust adheres to the photoreceptor after transfer, the residual toner and foreign matter are removed by a cleaning device including a cleaning blade and the like in preparation for the next image forming operation. . That is, the cleaning blade is a means for scraping residual toner and the like adhered to the surface of the photoconductor when the photoconductor rotates by bringing the tip of the cleaning blade into contact with the surface of the photoconductor. By the way, when the number of continuous images formed becomes large, the amount of foreign matter such as paper dust accumulated at the tip of the cleaning blade becomes large, and the cleaning performance is reduced. Therefore, it is general that the photoreceptor is rotated reversely after the completion of a certain amount of print job to clean the cleaning blade. The cleaning performance of the cleaning blade of the photoconductor is reduced due to wear of the blade, and in an apparatus that performs toner recycling, the cleaning performance is reduced over time due to an increase in paper dust contained in toner to be developed. If the cleaning blade is not sufficiently cleaned and foreign matters remain attached, good cleaning properties cannot be maintained, and black streak images due to poor cleaning are likely to occur. Further, the cleaning property of the cleaning blade by reversing the photoreceptor is not constant because the characteristics of the rubber constituting the cleaning blade and the toner charge amount change depending on the use environment such as temperature and humidity. Generally, a low-temperature, low-humidity environment tends to have poor cleaning properties.

Japanese Patent Application Laid-Open No. 9-204127 discloses a counter which can set a plurality of types according to the difference in the paper quality (the amount of generated paper dust) of the transfer paper using the interval at which the cleaning blade is cleaned. There has been disclosed a technique in which the cleaning blade is cleaned by selectively rotating the photoconductor in an alternate manner. However, the cleaning property of the cleaning blade by reversing the photoreceptor as described above is a condition other than the paper quality of the transfer paper, that is, the number of image formation, the temperature inside and outside the apparatus,
Although the present invention does not take these conditions into account despite the fact that it greatly changes depending on environmental conditions such as humidity, sufficient cleaning properties cannot be obtained.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and has been made in consideration of the above circumstances, and has a photosensitive member which is rotationally driven in both forward and reverse directions, and a cleaning device which abuts a tip of the photosensitive member surface to clean the surface. An image forming apparatus having a blade, configured to clean foreign matter such as paper dust attached to the tip of the cleaning blade by reversing the photoconductor, under conditions other than the paper quality of the transfer paper, that is, By changing the cleaning interval of the cleaning blade in consideration of environmental conditions such as the number of formed images and the temperature and humidity, it is possible to maintain good cleaning performance over a long period of time and prevent black streaks from being generated due to poor cleaning. It is an object to provide a forming device.

[0005]

In order to solve the above-mentioned problems, a first aspect of the present invention is a photoreceptor which is rotationally driven by a driving source, and a cleaning blade which abuts a tip of the photoreceptor surface to clean the surface. And a control device for controlling the drive source to rotate the photoconductor in both forward and reverse directions and to rotate the photoconductor in a direction opposite to the image forming direction to clean the cleaning blade. An image forming apparatus, comprising: a replacement detection device for detecting the attachment / detachment of the process cartridge to / from the image forming apparatus main body; and a blade cleaning counter for setting a cleaning interval of the cleaning blade based on the number of formed images. The controller selectively selects the set value of the blade cleaning counter and the number of image formation reaches the set value. Each time that the photosensitive member is reversed performs cleaning of the cleaning blade, and selects the interval for cleaning the cleaning blade in accordance with the number of image formation by the process cartridge. That is, the cleaning performance of the cleaning blade of the photoreceptor is worn,
In particular, in an apparatus that recycles toner, it decreases over time due to an increase in paper dust contained in the toner to be developed. According to the present invention, by changing the cleaning interval of the cleaning blade in accordance with the number of used process cartridges (the number of formed images), it is possible to maintain good cleaning performance over a long period of time and prevent black streak images due to poor cleaning. it can. In the invention according to claim 2, the image forming apparatus main body includes a temperature detecting device for detecting the temperature inside and outside the device main body, or a humidity detecting device for detecting humidity inside and outside the device main body, and the control device is configured to detect each temperature. The cleaning interval of the cleaning blade is selected according to the detection result of the apparatus. That is, the cleaning property of the cleaning blade by reversing the photoreceptor fluctuates when the rubber characteristics of the blade and the toner charge amount change depending on the use environment. Generally, a low-temperature, low-humidity environment tends to have poor cleaning properties. The present invention can maintain good cleaning performance over a long period of time by changing the cleaning interval of the cleaning blade according to the detection result of the temperature and humidity detection unit,
It is possible to prevent the occurrence of black streak images due to defective cleaning.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. FIGS. 1A and 1B show the main part (image forming part) of a laser copying machine according to the present invention.
The schematic configuration of is shown. In the drawing, reference numeral 10 denotes a drum-shaped photoconductor serving as an image carrier. A roller-shaped charging device 11 is provided around the photoreceptor 10, and a developing device 12, a transfer device 13, a paper separating device 14, and the like are arranged in this order from the charging device 11 along the rotation direction O of the photoreceptor 10. Cleaning device 15
Is provided. To make a copy, set the original on a contact glass (not shown) and then press the copy switch.
Then, the image of the document is read by an optical reading device (not shown), and at the same time, the paper P is transported between the photoconductor 10 and the transfer device 13. On the other hand, as the photoconductor 10 rotates, the charging device 1
1, the surface is uniformly charged, the surface is irradiated with laser light L from an optical writing device (not shown) to perform writing, and an electrostatic latent image of the read original image is formed on the photoconductor 10; Subsequently, when the toner passes through the developing device 12, toner is adhered to sequentially visualize the electrostatic latent image. Then, the transfer device 13 transfers the visible toner image formed on the paper P conveyed between the photoconductor 10 and the transfer device 13 as described above. After the transfer, the paper P is separated from the electrostatically adhered photoreceptor 10 by discharge in the paper separating device 14,
The sheet is conveyed to a fixing device (not shown), where the transferred image is fixed, and is discharged to a sheet discharging unit (not shown). Paper separation device 14
Alternatively, a separating claw may be provided to mechanically separate the photosensitive member 10 from the photosensitive member 10. On the other hand, the photoconductor 10 after image transfer
After the residual toner on the surface is scraped off by a cleaning blade 17 provided in the cleaning device 15 and the surface is cleaned, the surface is initially discharged by a discharging lamp (not shown) to initialize the surface potential. Be transformed into By the way, in this laser copying machine, the above-described photoconductor 10, charging device 11, developing device 12, cleaning device 15 and the like are integrated by one unit case 19 shown in FIG. The unit (process cartridge) 20 is configured. Although not shown, the photoreceptor unit 20 is replaceable by being attached between side plates provided to face each other in the main body of the copying machine.

Now, in such a laser copying machine,
As shown in FIG. 1A, the developing device 12 has a developer accommodating portion 21 provided on a lower side and a developer carrying portion 2 provided on an upper side.
2 is provided. The developer accommodating section 21 is provided with a first agitating member 23 and a second agitating member 24 for accommodating a two-component developer and conveying the developer while agitating the developer. Although not shown, a toner concentration sensor for detecting a mixture ratio of toner and carrier in the developer is provided. Before use, the space between the developer holding portion 22 and the developer carrying portion 22 is sealed with a sealing member (not shown). The developer accommodating section 21 is provided with a new toner supply port and a recycled toner supply port on one side in the longitudinal direction thereof, each opening upward. Then, the toner entering through the supply ports is conveyed by the first stirring member 23 and the second stirring member 24 so as to circulate toward the other end in the longitudinal direction. On the other hand, as shown in FIG. 1A, a developing roller 28 is provided in the developer carrying portion 22 at a position facing the photoconductor 10 through a developing window 27. Further, a developing doctor 29 for controlling the supply amount of the developer to the photoconductor 10 is provided. The cleaning device 15 has a cleaning device 15a in its case 15a.
A transport screw (rotary transport member) 30 for transporting the remaining toner scraped off by the blade 17 is disposed parallel to the axial direction of the photoconductor 10. The transfer screw 30 is shown in FIG.
As shown in (b), one end 31a of the shaft portion 31 is provided so as to enter the fall path 35 from a fall path entrance 33 provided above the front plate 19a of the unit case 19. The falling path 35 is formed by attaching the peripheral wall 36 to the front
The cover is provided on the outer surface of a, and a front side thereof is removed and a cover is omitted in FIG. Fall path 35
The peripheral wall 36 is partially inclined on the bottom surface a of the peripheral wall 36 between the fall path exit 37 and the fall path entrance 33 leading to the recycle toner supply port 26 of the developing device 12 described above, and remains on the inner surface of the inclined portion. A falling surface 36b of the toner is formed. And
In the developing device 12, at the time of copying, a drive motor (not shown) is driven, the drive is transmitted to rotate the developing roller 28, and the stirring members 23 and 24 are rotated to stir the developer.
The toner and the carrier are conveyed to the developing roller 28 while being frictionally charged. On the other hand, by applying a predetermined bias to the developing roller 28, toner in the developer is electrostatically attached to the surface of the photoreceptor 10, and the latent image on the surface is visualized. On the other hand,
In the tanning device 15, the rotational force of the photoconductor 10 is transmitted via a gear to drive the transport screw 30 to rotate.
The residual toner removed from the cleaning case is conveyed by the conveying screw 30 and collected on the front side in the cleaning case 15a.
(B) As shown by an arrow in the figure, it is dropped on the falling surface 36b from the falling path entrance 33, and further dropped by the falling surface 36 as shown by the arrow.
(b) and is collected in the developer accommodating section 21 from the falling path exit 37 through the recycling toner supply port. Photoconductor 1
Numeral 0 is driven by a driving device (drive source) using a motor (not shown) capable of rotating forward and backward, and when the image is formed, the rotating direction is O.
The paper dust gradually accumulates at the tip of the cleaning blade while rotating in the same direction. On the other hand, by rotating in the reverse direction O ′, paper dust attached to the blade tip can be removed. The reverse rotation operation is set so as to be continuously performed every time the normal rotation operation of the motor is stopped.

Next, an embodiment corresponding to claim 1 will be described based on a block diagram of a control system shown in FIG. An embodiment corresponding to claim 1 is a photoconductor 10 that is rotationally driven by a drive source, and a cleaning blade 1 that abuts a tip of the photoconductor surface to clean the surface.
And a control for cleaning the cleaning blade by controlling the driving source to rotate the photoconductor in both forward and reverse directions and to rotate the photoconductor in a direction opposite to that during image formation. The image forming apparatus includes a device (control unit) 39, an exchange detecting device for detecting the attachment / detachment of the process cartridge to / from the image forming apparatus main body, and a blade cleaning counter 40 for setting a cleaning interval of the cleaning blade based on the number of formed images. Related to an image forming apparatus. In the present embodiment, the control device 39 alternately selects the set value of the counter 40 and reverses the photoconductor 10 to clean the cleaning blade 17 every time the number of image formations reaches the set value, thereby performing the process. The feature is that the interval at which the cleaning blade is cleaned is selected according to the number of images formed by the cartridge.

In FIG. 1, reference numeral 40 denotes a blade cleaning counter. The blade cleaning counter 40 counts the number of sheets of transfer paper counted by a paper passage counter (not shown). The drive device 41 is controlled to rotate the photoreceptor 10 in the reverse direction to set an interval for blade cleaning (blade cleaning). Reference numeral 42 denotes a used number counter of the process cartridge. When a new process cartridge is set, the counter is cleared mechanically by a push switch (exchange detection device) or electrically by a bar code or the like (not shown). The total number of used process cartridges is counted. The blade cleaning counter 40 is based on the numerical value counted by the process cartridge counter 42 as shown in FIG.
From Table.1 shown in FIG. 7A, the number of sheets (M) until the photoreceptor 10 is reversed is automatically set. The number of sheets in Table 1 is set by dividing the number of used process cartridges by a predetermined number of sheets, such as 10,000 sheets or 20,000 sheets, and by keeping the number of sheets (M) constant within the range of each number of used sheets, the number of used sheets is regulated. When it exceeds the range, the interval (M) of the number of reverse rotations of the photoconductor is shortened. That is, the setting is such that the blade cleaning interval becomes shorter as the number of sheets used increases. That is, in this example, when the number of used sheets N1 is between 0 and 10,000 sheets, the number of sheets (M) until the photosensitive member is reversed is set to 300 sheets, but the number of used sheets exceeds 10,000 sheets. Range within 30,000 sheets, 3
Over 50,000 sheets and within 50,000 sheets, 5
When the number of sheets exceeds 0000, the interval between the sheets is 100
The number is set so as to gradually increase by 50 sheets or 50 sheets.
The blade cleaning counter 40 counts these 100 sheets and 50 sheets.

FIG. 4 is a block diagram of a control system according to a second embodiment of the present invention. In the invention of claim 2,
The control device 39 detects a temperature inside or outside the image forming main body (temperature sensor) 43 or a humidity detecting device (humidity sensor) 44 that detects humidity inside or outside the image forming main body.
The interval at which the cleaning blade 17 is cleaned is selected in accordance with the result of the detection. That is, in the figure, reference numeral 40 is a blade cleaning counter,
The blade cleaning counter 40 counts the number of transfer paper sheets counted by a sheet passing counter (not shown).
Based on this count result, the control device 39
1 to control the photoreceptor 10 in the reverse direction to set an interval for blade cleaning (blade cleaning) (photoreceptor reversal sheet number interval (M)). The photoreceptor reversal sheet number interval (M) counted by the blade cleaning counter 40 is set to be different depending on each temperature or humidity range measured by each of the sensors 43 and 44. FIG. 3 is based on numerical values obtained by the temperature sensor 43 or the humidity sensor 44, respectively.
(B) According to Table.2 or Table.3 shown in (c), the sheet interval until the photoreceptor 10 is reversed is automatically set. Tables 2 and 3 are set so that the reverse rotation interval of the photoconductor becomes shorter as the temperature and humidity conditions become more severe for photoconductor cleaning. That is, first, in the example of FIG. 3B, the measured value (T ° C.) of the temperature sensor is divided into a range of 15 ° C. or less, a range of 15 to 25 ° C., and a range of 25 ° C. or more. The photoreceptor reversal sheet number interval (M) is made different in each temperature range, the sheet number interval is set to a constant value in one temperature range, and the sheet number interval becomes longer as the temperature range becomes higher. This is the same for the measurement value (H% Rh) of the humidity sensor shown in FIG. Also,
As shown in Table 4 in FIG. 3D, when the measured value of the temperature sensor 43 and the measured value of the humidity sensor 44 are combined to set the interval of the photosensitive member reversal, the blade can be more effectively cleaned. Furthermore, it is more effective to provide a table in which the number of used process cartridges and all the measured values of the temperature sensor 43 and the humidity sensor 44 are combined and set the number of sheets until the photosensitive member is reversed. still,
The numerical values shown in each of the above Tables are merely examples.

FIG. 5 is a flowchart of an embodiment according to the first aspect. First, in step 101, the control device 39 checks the count value of the process cartridge counter 42 for counting the number of process cartridges used, and from Table.1 in FIG. The interval (M) is read, and the blade cleaning counter is set to the number interval (M) (step 103). Next, the operator who is about to make a copy sets the number of copies (the number of images formed) n (105). At this time, the controller 39 compares the number n of copies with the interval M (107). If the number n of copies is smaller, the controller 39 copies n sheets as they are (109). Give instructions,
The photosensitive member 10 is reversed, the blade is cleaned (111), and the process ends. When the number of copies n exceeds the set value (interval) M in step 107, M copies are made (113), and the copying is interrupted once to clean the blade (115). Thereafter, the number of remaining copies is checked (11
7) If the number of remaining copies is larger than the number M, the process returns to step 113; if not, the copy is completed (11).
9), cleaning of the blade is completed (111).

FIG. 6 is a flowchart corresponding to claim 2. First, in step 201, the control device 39
Confirms the measurement value of the temperature sensor 43, and confirms Tabl in FIG.
From e.2, the photoconductor reverse rotation number interval (M) corresponding to the current temperature range is read, and the blade cleaning counter 4 is read.
0 is set as the number interval (M) (step 20).
3). Next, the operator who is about to make a copy,
Set the number of copies (number of images formed) n (20
5). At this time, the controller 39 compares the number n of copies with the interval M (207). If the number n of copies is smaller, the controller 39 copies n sheets as they are (209). An instruction is issued, the photoconductor 10 is reversed, the blade is cleaned (211), and the process ends. If the number of copies n exceeds the set value (interval) M in step 207, M copies are made (213), and the copying is interrupted once to clean the blade (215). Thereafter, the remaining copy number is checked (217). If the remaining copy number is larger than the number M, the process returns to step 213. If the remaining copy number is smaller, the copy is completed (219), the blade is cleaned (211), and the process ends.

As described above, according to the present invention, the photosensitive member 10
In the image forming apparatus configured to clean foreign matter such as paper dust adhered to the tip of the cleaning blade 17 by reversing the conditions, conditions other than the paper quality of the transfer paper, that is, environmental conditions such as the number of formed images, temperature and humidity, etc. By sufficiently changing the cleaning interval of the cleaning blade in consideration of the above, it is possible to provide an image forming apparatus which can maintain good cleaning performance for a long period of time and can prevent generation of a black stripe image due to poor cleaning.

[0014]

As described above, according to the present invention, an image forming apparatus provided with a photoreceptor driven to rotate in both forward and reverse directions and a cleaning blade for abutting the tip of the photoreceptor surface to clean the surface. In the apparatus configured to clean foreign matter such as paper dust attached to the tip of the cleaning blade by reversing the photoconductor, conditions other than the paper quality of the transfer paper, that is, the number of formed images, temperature and humidity, etc. The present invention provides an image forming apparatus capable of maintaining good cleaning performance over a long period of time and preventing the occurrence of a black streak image due to poor cleaning by changing the cleaning interval of the cleaning blade in consideration of the environmental conditions. Aim. That is, according to the first aspect of the invention, the image forming unit is formed of a process cartridge, the apparatus main body is provided with a process cartridge replacement detection device and a used sheet counter, and an interval for cleaning the cleaning blade according to the used number of the process cartridge is set. By choosing
Without deteriorating the cleaning performance of the cleaning blade over time,
Good cleaning properties can be maintained over a long period, and black streak images due to poor cleaning can be prevented.
That is, not only the cleaning performance of the cleaning blade of the photoreceptor deteriorates due to abrasion, but also in an apparatus that recycles toner, in particular, decreases over time due to an increase in paper dust contained in the toner to be developed. According to the present invention, by changing the cleaning interval of the cleaning blade in accordance with the number of used process cartridges (the number of formed images), it is possible to maintain good cleaning performance over a long period of time and prevent black streak images due to poor cleaning. it can.

According to a second aspect of the present invention, the apparatus main body is provided with a temperature detecting device and / or a humidity detecting device for the outside air or the machine, and an interval for cleaning the cleaning blade is selected in accordance with a detection result of the detecting device. Therefore, regardless of the change in cleaning performance of the cleaning blade due to environmental changes,
Good cleaning properties can be maintained over a long period, and black streak images due to poor cleaning can be prevented.
That is, the cleaning property of the cleaning blade by reversing the photoreceptor fluctuates when the rubber characteristics of the blade and the toner charge amount change depending on the use environment. Generally, a low-temperature, low-humidity environment tends to have poor cleaning properties. In the present invention, by changing the cleaning interval of the cleaning blade based on the detection result of the temperature / humidity detecting means, it is possible to maintain good cleaning performance over a long period of time, and to prevent the occurrence of black streak images due to poor cleaning.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams illustrating a schematic configuration of a main part (image forming unit) of an image forming apparatus according to an embodiment of the present disclosure.

FIG. 2 is a block diagram showing a control system of the image forming apparatus according to one embodiment of the present invention.

FIGS. 3A to 3D are tables showing tables corresponding to each embodiment.

FIG. 4 is a block diagram showing a control system of an image forming apparatus according to another embodiment of the present invention.

FIG. 5 is a flowchart showing a control procedure according to an embodiment of the present invention.

FIG. 6 is a flowchart showing a control procedure according to another embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 10 photoconductor, 11 charging device, 12 developing device, 13
Transfer device, 14 paper separating device, 15 cleaning device, 15a case, 17 cleaning blade,
19 Unit Case, 20 Photoconductor Unit (Process Cartridge), 39 Controller, 40 Blade Cleaning Counter, 41 Drive, 42 Process Cartridge, 43 Temperature Detector (Temperature Sensor), 44
Humidity detector (humidity sensor).

Claims (2)

[Claims] A process cartridge provided with a photoreceptor rotatably driven by a driving source, a cleaning blade for abutting a tip of the photoreceptor surface to clean the surface, and controlling the driving source to remove the photoreceptor. A control device for cleaning the cleaning blade by rotating the photosensitive member in both forward and reverse directions and rotating the photosensitive member in a direction opposite to the direction of image formation, and a replacement detection device for detecting attachment and detachment of the process cartridge to and from the image forming apparatus main body. And a blade cleaning counter for setting a cleaning interval of the cleaning blade based on the number of formed images, wherein the controller selectively selects a setting value of the blade cleaning counter. Each time the number of sheets to be formed reaches the set value, the photosensitive member is reversed to clean the cleaning blade. It was carried out, the image forming apparatus and selects the interval for cleaning the cleaning blade in accordance with the number of image formation by the process cartridge. 2. The image forming apparatus main body includes a temperature detecting device for detecting a temperature inside and outside the device main body, or a humidity detecting device for detecting humidity inside and outside the device main body, and the control device includes a detecting device for each of the detecting devices. 2. The image forming apparatus according to claim 1, wherein an interval at which the cleaning blade is cleaned is selected according to a detection result.