JPH01108592A - Lubricating property holding device for blade - Google Patents

Abstract

PURPOSE:To supply a toner to a blade to match a state of an image formation processing by providing a toner quantity control means for controlling the quantity of the toner which is allowed to adhere onto a latent image carrying body in accordance with a series of image forming frequency. CONSTITUTION:The title device is provided with a toner quantity control means 4 for controlling the quantity of a toner 2 which is allowed to adhere onto a latent image carrying body 1 in accordance with a series of image forming frequency. As for a control state by this toner quantity control means 4, generally speaking, the more the image forming frequency becomes, the more the toner supply quantity becomes. That is, until the machine stops after a series of image formation processings is ended, the toner quantity control means 4 controls the quantity of the toner 2 which is allowed to adhere to the latent image carrying body 1 in accordance with the image forming frequency in the image formation processing. In such a way, the toner 2 whose quantity is controlled in accordance with the image forming frequency is supplied to a blade 3.

Description

[Detailed Description of the Invention] U Industrial Application] The present invention relates to a device for maintaining the lubricity of a blade that scrapes off toner remaining on a latent image carrier after transfer in a copying machine or the like. relates to a blade lubricating device that deposits toner on a latent image carrier and supplies it to a blade for removing residual toner between the end of a series of image forming processes and the stop of the machine.

[Prior Art] In electrophotographic image forming apparatuses such as copying machines and printers, a latent image formed on a latent image carrier such as a photoconductor is converted into a toner image, and this toner image is transferred onto paper or the like. to form the desired image. Further, since toner remains on the latent image carrier after the toner image F is transferred, so-called toner cleaning is required in this type of image forming apparatus to remove this residual toner.

There are various methods for this toner cleaning, but if we focus on the blade cleaning method in which the toner adhering to the latent image bearing member is scraped off with a blade, the toner cleaning method is based on the sliding friction between the latent image bearing member and the blade. In order to prevent blade curling, chattering, etc., it is necessary to maintain lubricity between the blade and the latent image carrier.

Therefore, in conventional devices that maintain the lubricity of this blade, for example, in an electronic copying machine, the amount of lubricity on the photoreceptor is removed from the time when a series of copies of a set number of sheets is completed until the machine stops. The toner is attached to the blade and the toner is forcibly applied to the blade. This results in
The lubricating component contained in the toner smoothes the sliding property between the photoconductor and the blade, preventing wear on the blade edge, and also prevents the blade from curling up or chattering, thereby reducing the toner flow during the image forming process. It has a reliable scraping effect. In addition, in the case of this type of copying machine, the normal copy size (A4° 84, etc.) is generally smaller than the maximum copy size (A3, etc.).
In this case, there is almost no chance that a toner image will be formed in the area of the photoreceptor corresponding to the difference between the maximum copy size and the normal size, and the supply of residual toner during normal copying cannot be expected; Forced toner supply is especially necessary in order to maintain the lubricity of the blade.

Forcible adhesion of toner onto the photoreceptor is carried out, for example, by simultaneously turning off a charger and an erase lamp disposed upstream of the developing device after copying is completed and immediately before the machine is stopped.

That is, when the charger and erase lamp are turned off, the photoreceptor between them is charged, and when that area passes through the developing device, toner is attached and supplied to the blade as it is. Therefore, in conventional devices, each time a series of copies corresponding to the set number of sheets is completed, a toner image with a width corresponding to the distance between the charger and the erase lamp is formed on the photoreceptor, and a certain amount of toner is It was supplied to the blade.

[Problems to be Solved by the Invention] As mentioned above, a certain amount of toner is deposited on the latent image forming carrier between the end of a series of image forming processes and the stop of the machine. Conventional devices that supply toner to the blade do not properly supply toner to the blade.

This is because toner is always supplied at a constant level even if the number of times of image formation in a series of image forming processes is large or small. In other words, a large number of image formations in a series of image forming processes means that the sliding time between the blade and the latent image carrier is long, and a large amount of toner is originally required to maintain lubricity. Conversely, if the number of times of image formation is small, the amount of toner may also be small.

Therefore, if the number of image formations in a series of image forming processes is large, there is a risk that the supplied toner may become insufficient and lubricity cannot be ensured, whereas if the number of image formations is small, the supplied toner may become excessive. This can also cause the inside of the aircraft to get dirty.

Therefore, an object of the present invention is to make it possible to supply toner to a blade in accordance with the mode of a series of image forming processes.

[Means for Solving the Problems] As shown in FIG. 1, the present invention, as shown in FIG. Blade 3 for adhering and removing residual toner
The technical means for solving the above problem in the blade lubricity maintaining device is to adjust the speed of the latent image carrier according to the number of times of image formation described above. The apparatus is equipped with a toner amount control means 4 for controlling the amount of toner 2 deposited on the toner 1. The control mode of the toner amount control means 4 is such that the amount of toner supplied generally increases as the number of times a series of image formation increases.

Further, the toner amount control means 4 may be configured to control the area of toner adhering to the latent image carrier 1 according to the number of consecutive image formations, or to control the density of toner adhering to the latent image carrier 1. is possible. In the former case, for example, in the example mentioned above, this can be achieved by controlling the timing of shutting off the charger and erase lamp, and in the latter case,
For example, this can be achieved by controlling the stop timing of the toner developing device, the amount of irradiation from the erase lamp, the amount of charging, and the like.

[Operation] The toner amount control means 4 causes the toner amount to adhere to the latent image carrier 1 in accordance with the number of times of image formation in the series of image forming processes from the end of the series of image forming processes until the machine stops. 2m, and the amount of toner 2 is controlled according to the number of times of image formation.
is provided to the blade 3.

[Example] Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a diagram showing an example of an image forming apparatus to which the blade lubricity maintaining device according to the present invention is applied.

This is an example of a two-color copying machine,
In FIG. 2, below the platen 11 there are mirrors 13, 14, 15, 17, 18, 19 along with the exposure lamp 12.
and an exposure optical system such as a lens 16 are arranged, and the platen 1
When scanning the original 110 on 1, the light reflected from the surface of the original 10 from the exposure lamp 12 is reflected by the mirror 13.14.
15, a lens 16, and mirrors 17, 18, and 19 to guide the photosensitive drum 20 to the exposure position. Around the photosensitive drum 10, a charger 21 and a first developing device 22 for red toner are installed to execute the image forming process.
a, a second developing device 22b1 for black toner, a transfer device 23, a peeling corotron 24, and a peeling claw 25 at the rear stage.
, a cleaning device 26 having a blade 26a that slides on the surface of the photoreceptor 20 is disposed. Further, an erase lamp 27 for optically eliminating charges in the interimage portion of the photosensitive drum 20 is arranged upstream of the first developing device 22a. Then, the paper sent out from the cassette 30 is supplied to the transfer position (transfer unit 23 and peeling corotron 24 arrangement position) via the paper feed conveyance path 32, and after transferring the toner image, the paper is fed to the fixing device 35 via the conveyance path 34. The image is fixed by being sent to Thereafter, the paper on which the image has been fixed is discharged to the tray 38 via the discharge conveyance path 36.

Note that a return conveyance path 33 is provided downstream of the fixing device 35 to return the fixed paper to an intermediate tray (not shown) for multiple copies or backside copying, and the return conveyance path 33 Gate 37 is discharge conveyance route 3
6 and the return conveyance path 33.

FIG. 3 is a block diagram showing an example of the basic configuration of a toner supply control system related to maintaining lubrication of the blade 26a.

In the same figure, 40 is a CPL that performs overall overall control.
J, 41 is a ROM that stores programs, tables, etc.
42 is a RAM for reading necessary data etc. obtained as a result of the operation by the CPU 40;
The RAMs 42 are each connected to a bus. Operation signals from the numeric keypad switch 45 and mode switch 46 provided on the console panel of the copying machine are input to the CPU 40 side via the input interface 43, and various modes,
The number of copies etc. are recognized. In addition, a power source 47 for the main motor 48 of the machine, a high voltage power source 49 for the charger 21, a power source 501 for the erase lamp 27, and a power source 501 for the second developing device 22b for black toner are supplied to the drum 20 from the CPU 40 side via the output interface 44. Control signals relating to toner image formation thereon are provided.

The ROM 41 has a relationship between the number of copies and the difference Δt between the cutoff timings of the charger 21 and the erase lamp 27 at the end of copying, for example, according to a linear characteristic Q shown in FIG.
is stored as a table corresponding to In other words, when the number of copies is m, both cutoff timings are simultaneous (Δt=0)
Therefore, when the number of bee sheets is more than m, the timing to shut off the erase lamp 27 is early (Δt>O), and when the number of bee sheets is less than m, the timing to shut off the erase lamp 27 is late (Δt<Q). It is something.

Next, the operation will be explained according to the timing chart shown in FIG.

Along with the start operation, the main motor 48 and the charger 21 are turned on, and in synchronization with the scanning of the original by the optical system, the developer mag roll is used to supply toner to the image area, and the ink image area is used to remove static electricity. The erase lamp 27 does not turn on and off alternately. And for example,
When the set number of copies is m and the erase lamp 27 is turned on at the end of m image formation, Δ is calculated based on the table in the ROM 41 corresponding to the characteristic Q shown in FIG.
1=0 is set, and the power source 49.50 to the charger 21 and the erase lamp 27 is cut off at the same time (time ts in FIG. 5). Then, at the time ts when the power is cut off, as shown in FIG. 6, an area having a width l formed between the charger 21 and the erase lamp 27 on the photosensitive drum 20 remains in a charged state.

Then, the mag roll is temporarily driven at a timing (time to) immediately before the area is expected to reach the second developing device 22b position due to the rotation of the photosensitive drum 20.
When the area passes through the second developing device 22b position in this state, black toner in the developing device 22b adheres to the area of width l, and as the photosensitive drum 20 rotates, the blade 26a of the cleaning device 26 is supplied to Thereafter, when time te is reached, the power supply 47 to the main motor 48 is cut off, resulting in the aircraft stopping.

In the above example, the erase lamp 27 and charger 21 were turned off at the same time;
The relationship between the off-timing difference Δt between the charger 7 and the charger 21 and the toner area formed on the photosensitive drum 20 is as shown in FIG. That is, when Δ1=0, as described above, the toner area TO of width p is created as shown in FIG. 8(b).
is formed, and the off timing of the erase lamp 27 is Δ
When the circumferential speed of the photosensitive drum 20 is increased by t1, the charging area increases by .DELTA.t1 until the charger 21 is turned off, so as shown in FIG. 8(a), the width (1+
On the other hand, when the off timing of the erase lamp 27 is delayed by Δt1, a toner area Td with a width (Ij+v·Δti) is formed as shown in FIG. 8(c). . The relationship between this Δt and the toner area width is linear.

Therefore, by shifting the off-timing of the erase lamp 27 back and forth around the off-timing ts of the charger 21 as shown in FIG. 5 according to the number of copies, based on the characteristic Q shown in FIG. The width of the region is controlled,
As a result, the amount of toner supplied to the blade 26a of the cleaning device 26 is controlled.

As mentioned above, the relationship between the number of copies and Δt shown in FIG. 4 is determined by considering the characteristics of the copying machine shown in FIG. 7, the properties of the toner used, etc. The toner supply is determined in such a way that just the right amount of toner can be supplied to maintain the quality.

In the above embodiment, the amount of toner supplied to the blade 26a is controlled by controlling the width, that is, the area, of the toner area formed on the photosensitive drum 20 according to the number of copies to be made on the photosensitive drum 20. It is also possible to control the supply amount by controlling the toner concentration adhering to the toner.

For example, the specific control is as follows. In Figure 5,
The operation of the developing machine 22b mag roll immediately before the machine stops is performed at a time to just before the toner area formed on the photosensitive drum 20 reaches the position of the second developing machine 22b by controlling the off timing of the erase lamp 27. When the toner area passes through the second developing device 22a position, the mag roll is in a state of rotation due to inertia. Therefore, if the mag roll is operated at 11 before the above time to, the speed of the mag roll when the toner area passes becomes slower and the toe density from the second developing device 22b becomes lower. If the mag roll is operated in the latter step 12, the speed of the mag roll when the toner area passes becomes higher, and the toner concentration from the second developing device 22a becomes higher. As a result, the adhesion toner concentration is controlled by controlling the operation timing of the second developing device 22b mag roll when the machine is stopped according to the number of copies in a series, and as a result, the amount of toner supplied to the blade 268 is controlled. become. The concentration of the adhered toner can also be controlled by controlling the emission of the erase lamp 27 or by controlling the amount of charge in the charger 21.

Incidentally, when the paper is supplied to the transfer position, it is subjected to the feeding action of a feed roll or the like, and due to the friction between the roll and the paper surface, paper dust is likely to be generated at the position where the paper comes into contact with the roll. Then, when the paper is fed to the transfer position, this paper powder adheres to the photosensitive drum, and it is further transferred to the cleaning device 26.
When reaching the blade 26a, the lubricity of the blade decreases.In order to prevent the lubricity of the blade from decreasing due to this paper powder, the toner supply control according to the number of copies as described above is performed in accordance with the position of paper roll contact. Control is added to increase the amount of toner supplied onto the photosensitive drum 20.

In order to realize this control, a plurality of erase lamps 27 are provided.
The LEDs are arranged in the axial direction of the photosensitive drum 20, forming a so-called LED array structure. In such an erase lamp 27, the LED at the position corresponding to the paper roll contact position on the photosensitive drum 20 is, for example, L in FIG.
E D (i) to LED (inn) (n pieces), and L E D (j) mustard ED (inn) (
Unlike other LEDs that are controlled mainly based on the off timing ts of the charger 21, such as n LEDs, the off timing is controlled in a range of Δt before and after the timing ts', which is earlier than this ts. .

As a result, as shown in Figure 10, the number of copies in a series is greater than m ((a) in the figure), m ((b) in the same figure), and less than m ((b) in the same figure). (C)) Both,
For the position corresponding to the paper roll contact position, please refer to ■・(
When ts-Ts'>thick, the toner area width increases, and the amount of toner supplied to the blade 26a at the relevant position is increased. This makes it possible to reliably maintain lubricity at the blade position corresponding to the paper roll contact position, which is particularly susceptible to the influence of paper dust.

In the above control, in which toner is supplied to the blade at the end of a series of copies, in principle, when a copying machine that has been stopped for a long time is started and the first copy is made, toner is not supplied to the blade for a long time. Copying will be performed without the In order to compensate for the lubricity of the blade during the first copy after being stopped for such a long time,
In an actual copying machine, in addition to the various controls mentioned above, for example, the charger and erase lamp are simultaneously turned off immediately before the machine stops during the warm-up cycle when the power is turned on, and the amount of toner is adjusted based on the off timing. may be supplied to the blade 26a.

Although the above embodiments have been described using a copying machine as an example, the present invention can also be applied to an electrophotographic printer or the like.

[Effects of the Invention] As explained above, according to the present invention, since the amount of toner to be supplied to the blade is controlled according to the number of times of image formation in a series, the blade can be adjusted to match the image formation mode in a series. It becomes possible to supply toner to Therefore, more appropriate toner is supplied to the blade from the end of a series of image forming processes until the machine stops, and the lubricity of the blade is maintained at an appropriate level at all times.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a diagram showing the configuration of the present invention, FIG. 2 is a diagram showing a structural example of an image forming apparatus in which the blade lubricity maintaining device according to the present invention is adopted, and FIG. Figure 4 is a block diagram showing an example of the basic configuration of a control system related to maintaining blade lubricity, and Figure 4 shows the number of copies and the off-timing difference Δ between the erase lamp and charger.
t. Figure 5 is a timing chart showing the operation up to the aircraft stop. Figure 6 is a diagram showing the positional relationship between the charger and erase lamp. Figure 7 is the erase lamp and charging. 8 is a characteristic diagram showing the relationship between the off-timing difference Δt of the device and the width of the toner area formed on the photosensitive drum. FIG. 8 is a diagram showing the state of the toner area formed on the photosensitive drum. FIG. FIG. 10 is a timing chart showing an example of control timing when configured with an LED array. FIG. 10 is a diagram showing the state of the toner area formed on the photosensitive drum by the operation of the erase lamp according to the timing chart shown in FIG. be. [Explanation of symbols] 1...Latent image carrier 2...Toner 3.26a...Blade 4...Toner amount control means 20...Photosensitive drum 21...Charger 22a...No. Developing machine 22b...Second developing machine 26...Cleaning device 27...Erase lamp Patent applicant Agent of Fuji Xerox Co., Ltd.
Patent attorney Tomohiro Nakamura (2 others) Figure 1-r\. Fig. 7 Fig. 8 (a) (b) (C) TuTO ball att ■・Δt1 Fig. 9 Δt4t] A

Claims (1)

[Scope of Claims] 1) After a series of image forming processes are completed and before the machine is stopped, toner (2) is deposited on the latent image carrier (1) and a blade for removing residual toner ( In the blade lubrication and maintenance device provided in 3), the toner (
2) A blade lubricity maintaining device characterized by comprising a toner amount control means (4) for controlling the amount of toner. 2) The blade according to claim 1, wherein the toner amount control means (4) controls the toner adhesion area to the latent image carrier according to the number of times the series of image formation is performed. lubricity retaining device. 3) The toner amount control means (4) controls the density of toner adhering to the latent image carrier in accordance with the number of times the series of image formation is performed.
A blade lubricity retaining device as described in .