JPH0322630B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for improving the cleaning performance of image recording devices such as copying machines and printers, and in particular, in a type that records images using an electrophotographic process. The present invention relates to an improvement in a cleaning performance improvement method for improving cleaning performance when cleaning residual toner on a toner image carrier with a blade.

[Prior Art] Conventionally, copy paper of multiple sizes, such as A3,
In a copier that can use copy paper of various sizes such as B4, A4, B5, etc., the following processing is applied to the photoreceptor after the exposure process of the original and before the development process, regarding the difference in paper size. There is something to do. In other words, when using multiple sizes of copy paper, the difference in paper size is detected by detecting the paper size of the copy paper being used, and adjusting the size of the drum on the photoreceptor drum according to the size of the copy paper. By lighting the lamp so that the remaining portion in the axial direction is irradiated with light before development, the latent image on the photoreceptor drum is erased and no toner image is formed on the photoreceptor drum. In other words, by using a lamp for erasing interim images provided on the front side of the developing machine, the light-emitting element of the lamp located outside the width of the copy paper being used is turned on outside the original image area. According to
Even if copying is performed with the platen cover open, the toner image is prevented from being formed on the photosensitive drum beyond the width of the copy paper, and this prevents the toner image from being formed on the photoreceptor drum when making reduced copies. This is to prevent unnecessary images from being formed on the copy paper.

[Problem to be solved by the invention]

However, some users may frequently use copy paper of smaller sizes, for example, B5 or A4 in the above example, among the large and small sizes of copy paper. For example, B5, A4,
Copying machines that can make full size copies or reduced copies of B4 and A3 size originals, mainly use B5 and A4 full size copies and B4 and A3 reduced copies, that is, B5 and A4 copy paper. This is the case for users who use it to make copies. Therefore, in a copier that performs processing such as erasing latent images before development depending on the copy paper size used as described above, if small-sized copy paper is frequently used, the photoreceptor drum There are many chances that toner will not adhere to areas outside the upper document image area. That is, in the case of center registration, for example, the rate at which toner images are formed on both sides of the photosensitive drum is lower than that at the center.

By the way, one method of cleaning the photoconductor of a copying machine is to use a cleaning blade to scrape off the toner from the surface of the photoconductor, and this type of blade cleaning method has been adopted as a method for cleaning the photoconductor. In this case, if the rate at which toner images are formed on both sides of the photoreceptor drum decreases as described above, this will lead to problems with the cleaner. In other words, toner contains lubricant, which maintains the sliding properties of the photoreceptor drum and cleaning blade, but as mentioned above, users mainly use B5 and A4 copy paper. If you use small-sized copy paper frequently, such as when making copies,
As mentioned above, there are many chances that toner containing lubricant will not adhere to areas outside the original image area on the photoreceptor drum, so lubricant will not be supplied to the entire edge of the cleaning blade, and toner will not adhere to areas outside the original image area. The frictional force between the photoreceptor drum portion and the cleaning blade becomes large, thereby damaging the edge portion of the cleaning blade.
If the edge of the cleaning blade is damaged, defects such as horizontal lines will appear on the copy, making it impossible to make good copies.

Conventional techniques for solving such technical problems include, for example, forming an area where charges are held uniformly over the entire length of the photoreceptor in the width direction for each copy cycle, and applying a developing device or A device has already been provided in which toner is attached by a developer supply means in a cleaning device, and a lubricant contained in the toner is supplied to the entire edge portion of the cleaning blade to prevent damage to the cleaning blade. (JP-A-56-80079, JP-A-59-
13265, JP-A-60-8887).

However, for this type of
Because toner is actively deposited on the charge retention area of the photoreceptor during each copy cycle,
Not only does the amount of toner consumed become extremely large, but in the case of the type disclosed in JP-A-60-8887, the device configuration is unnecessarily complicated due to the separate attachment of a developer supply means. creates new technical challenges.

Note that such technical problems may occur not only in copying machines but also in general image recording apparatuses that utilize an electrophotographic process, such as printers.

The present invention was made to solve the above technical problems, and aims to optimize the amount of toner consumed to be supplied to the cleaning blade while suppressing the complexity of the device configuration, thereby avoiding wasteful toner consumption. The present invention provides a method for improving the cleaning performance of an image recording apparatus.

[Means to solve the problem]

That is, the present invention is based on an image recording apparatus that can use recording sheets of a plurality of sizes and uses a blade cleaning method. A characteristic feature is that a band-shaped uniform charge holding area is formed over the entire widthwise length of the non-image area of the carrier, and a smaller amount of toner from the developing machine is attached to this uniform charge holding area than during development. That is.

[Effect]

According to the above-mentioned technical means, immediately before the job of the image recording device is completed and the image recording device is stopped, a band-like uniform charge is held across the entire widthwise length of the non-image area of the toner image bearing member. A region is formed.

Thereafter, when the uniform charge holding area passes through the development area of the developing machine, a smaller amount of toner is attached to the uniform charge holding area than during development,
A pale toner image is formed over the entire width of the toner image carrier, and then the image recording apparatus is stopped.

When the next job is started, the toner image carrier rotates, and the pale toner image formed on the toner image carrier passes the cleaning blade. The lubricant contained in the toner is supplied to the entire length of the part.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 schematically shows the inside of a copying machine to which the present invention can be used, which can use copy paper of multiple sizes and uses a blade cleaning method. In the figure, 1 is a platen cover, 2 is an arrow The exposure lamp is provided so as to be able to reciprocate in directions a and b, and the reflected light obtained when the exposure lamp 2 moves forward in the direction of arrow a passes through an optical path 3 to the surface of the photoreceptor, in the illustrated example, the photoreceptor drum 4. Exposure is performed by irradiating the surface.

Around the photoreceptor drum 4, there is a developing machine equipped with a charging corotron 5 that uniformly charges the surface of the photoreceptor drum 4, and a magnet roll 6 that performs development by depositing toner on the surface of the photoreceptor drum 4. 7. A transfer section 10 having a transfer corotron for transferring the toner onto the copy paper sent out from each tray 8, 9 and a peeling corotron for peeling the toner, and a cleaning blade 11 to remove toner from the surface of the photoreceptor drum 4 after transfer. A cleaner 12 for scraping off the intermediate image is provided, and a lamp (IIL) 13 for erasing the interimage is arranged in front of the developing device 7 so as to face the surface of the photoreceptor drum 4. has been done. Also,
Inside the copying machine, there is a transport mechanism 14 that transports the copy paper onto which the toner image has been transferred by the transfer section 10 and has been peeled off from the surface of the photoreceptor drum 4, and a transport mechanism 14 that transports the copy paper that has been peeled off from the surface of the photoreceptor drum 4. A fixing device 15 that performs fixing is provided.

The lamp 13 is a light source for erasing an interim image, and during a period after the original exposure process and before the latent image development process, the photosensitive drum 13 is
It also serves as a light source for irradiating light onto the remaining part of the drum in the direction of the drum axis to erase the latent image in that part, and as shown in FIG. It is composed of a lamp element 16 for emitting light. The case shown in the figure is an example of the arrangement of the lamp elements 16 for each light emission when the document is set using the center registration method. They are arranged symmetrically, and when A4 copy paper is used, for example, each lamp element 16 on both sides outside the A4 vertical feed width is controlled to be lit. Regarding this lamp 13 and the above-mentioned charging corotron 5, when making a single copy, the copy cycle for that one copy, and when making multiple copies, the copy cycle for the last number of copies. Then, just before the machine stops, both of them are turned off at the same time, for example, so that an area A on the surface of the photoreceptor drum 4 between the charging corotron 5 and the lamp 13 is charged, as shown in FIG. I try to leave it. Furthermore, in this embodiment, since the drive of the magnet roll 6 of the developing device 7 is stopped at the end of the copy cycle, the above-mentioned electric charge is The remaining area A of the photosensitive drum 4 is developed so that the toner adheres to the entire length of the drum in the axial direction.
The magnet roll 6 of the developing machine 7 is driven again for a predetermined period of time.

Next, the lamp 13 erases the latent image on both sides of the photoreceptor drum 4 corresponding to the size of the copy paper used, and the surface of the photoreceptor drum 4 is erased immediately before the job of the copying machine is completed and the machine is stopped. The operation of forming a toner image over the entire length of the drum in the axial direction will be explained with reference to the timing chart shown in FIG.

First, when copying a document using A4 copy paper, as shown in FIG.
The lamp element 16 located outside the vertical feed width of A4 copy paper is turned on outside the original image area, and the surface of the photoreceptor drum 4 on which a latent image is formed by exposure of the original is in such a lighting state. It passes under the lamp 13 and reaches the developing device 7.
By doing this, even if a copy is made with the platen cover 1 open, the photosensitive drum 4
No toner images are formed on either side of the image. Therefore, in the case of this copier, the maximum size of copy paper that can be used is A3, but as mentioned above,
If you use small size copy paper such as A4 frequently,
The rate at which toner images are formed on the surface of the photoreceptor drum 4 is lower at both sides than at the center of the photoreceptor drum 4, leading to trouble with the cleaner 12. Therefore, it is possible to prevent this and improve the cleaning performance. To achieve this, the copy cycle is changed as follows.

That is, just before the copy cycle ends and the machine stops, the charging corotron 5 is turned off by cutting off the power supply from the high voltage power source to the charging corotron 5 as shown in FIG. As shown in b, all the lamp elements 16 of the lamp 13 are also turned off at this point, and furthermore, in this example, at the same time as these charged corotrons 5 and the lamp 13 are turned off, the mag of the developing machine 7, which has already been stopped at the end of the copy cycle, is turned off. The network controller 6 is driven by X msec as shown in c in the figure. Charged corotron 5
When the lamp 13 and lamp 13 are turned off at the same time, electric charge remains on the entire surface of the photoreceptor drum 4 in area A shown in FIG. As it rotates in the direction of arrow c, it continues to move clockwise in FIG.
In this case, since the exposure lamp 2 is no longer lit and all the lamp elements 16 of the lamp 13 are also turned off as described above, the area A moves with charges remaining on the entire surface, and the photoreceptor moves. When the drum 4 rotates by an angle θ and the tip of the area A reaches the magnet roll 6, the drive of the magnet roll 6 is stopped, and thereafter the magnet roll 6 rotates in the direction of arrow d due to its inertia. Therefore, the portion of the region A where the charge remains passes through the portion of the magnet roll 6 that is rotating due to inertia. During this passage, toner is attached to area A, but unlike during normal development, the magnet roll 6 is rotating due to inertia.
Compared to the normal case, the amount of relative movement of the magnet roll 6 with respect to the photoreceptor drum 4 is reduced.
The amount of toner deposited is small, and a pale toner image is formed over the entire length of the drum in the axial direction in area A on the photoreceptor drum 4 where the charge remains. Therefore, if the toner adheres to the area A over the entire length of the drum in the axial direction just before the copying machine stops, then when the toner passes through the cleaning blade 11 of the cleaner 12, the cleaning blade 11 The lubricant contained in the toner is supplied to the entire length of the edge portion of the photosensitive drum 4 and the cleaning blade 11, thereby ensuring slidability between the photosensitive drum 4 and the cleaning blade 11.

In this way, in a copying machine that can use multiple sizes of copy paper and employs a blade cleaning method, a toner image is always formed on the entire length of the photoreceptor drum 4 in the drum axial direction immediately before the copying machine stops. Therefore, even if small-sized copy paper is used frequently, lubricant is supplied to the entire edge portion of the cleaning blade 11 due to the presence of the toner image formed as described above. It is possible to have the opportunity to be Therefore, as in the past, if small-sized copy paper is frequently used, the cleaning blade 1
1 is not damaged and it becomes impossible to obtain good copies, it is possible to prevent failure of the cleaning blade 11 due to large frictional force between the photosensitive drum 4 and the cleaning blade 11, and to obtain good copies for a long period of time. can.

〔Effect of the invention〕

As explained above, according to the method for improving the cleaning performance of an image recording device according to the present invention,
Even when small-sized recording sheets are frequently used, lubricant can be supplied to the entire length of the cleaning blade edge, preventing damage to the cleaning blade edge and ensuring good image quality for a long time. A recorded image can be obtained.

Particularly, according to the present invention, a uniform charge holding area is formed in a non-image area of a toner image bearing member immediately before a job of an image recording apparatus is finished and the image recording apparatus is stopped; Since the toner from the developing machine is allowed to adhere to the area in a smaller amount than during development, it is possible to reduce the amount of toner to the minimum necessary to prevent damage to the cleaning blade, and toner in the developing machine is not wasted. It is possible to effectively avoid the situation where the cleaner is consumed over time, to suppress the amount of cleaner to be collected, and to prevent the inside of the image recording apparatus from being contaminated.

Further, in the present invention, since the existing developing machine is used to supply lubricating toner to the cleaning blade, there is no fear that the device configuration will become unnecessarily complicated.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of the interior of a copying machine to which the present invention is applied, and FIG. 2 is a lamp in the drum axis direction of a lamp consisting of a large number of lamp elements arranged along the drum axis direction of a photoreceptor drum. An explanatory diagram to show the lighting state and the width of the applicable copy paper, FIG. 3 is an enlarged view of the photoconductor drum portion to explain the case where toner is attached over the entire length of the photoconductor drum in the axial direction, and FIG. 4 is an enlarged diagram of the photoconductor drum portion. This is a timing chart for explaining the present invention. Explanation of symbols, 4...Photosensitive drum, 5...Charging corotron, 7...Developing machine, 11...Cleaning blade, 13...Lamp.

Claims (1)

[Scope of Claims] 1. In an image recording apparatus that can use recording sheets of a plurality of sizes and uses a blade cleaning method, the toner image carrier A band-shaped uniform charge retention area is formed over the entire length of the non-image area in the width direction, and a smaller amount of toner from the developing machine is attached to this uniform charge retention area than during development. A method for improving the cleaning performance of an image recording device.