JPS6395488A - Method for improving cleaning capacity of copying machine - Google Patents

Abstract

PURPOSE:To control the sticking quantity of toner with the width dimension of a toner picture smoothing area so as to prevent a secondary fault, by forming the toner picture smoothing area by delaying the turning off timing of a destaticizing lamp from the turning off timing of an electrifier by a prescribed time. CONSTITUTION:When a toner picture smoothing area A, in which toner is stuck to a photosensitive body over its full width, is formed just before a copying machine is stopped after completion of copying operations, the toner picture smoothing area A is formed by delaying the turning off of a destaticizing lamp 6 from the turning off timing of an electrifier 5 by a prescribed time. Since the width dimension of the toner smoothing area A formed on the surface of the photosensitive body is controlled by means of the turning off timing of the electrifier 5 and destaticizing lamp 6 in such way, the quantity of the toner sticking to the toner picture smoothing area A can be controlled by means of the width dimension of the area A and the turning off timing of the drive of a developing device can also be set after the toner picture smoothing area A is formed. Therefore, occurrence of a secondary fault can be prevented.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a copying machine that can use copy paper of multiple sizes and employs a blade cleaning method as a photoreceptor cleaning method. Relates to methods for improving performance.

[Prior Art] In a copying machine that can use multiple sizes of copy paper, a static elimination lamp for erasing interim images is provided in front of the developing unit, and a portion located outside the width of the copy paper used is This discharge lamp is turned on to prevent an excess toner image from being formed on the photoreceptor beyond the width of the copy paper. In such a copying machine, for example, B
When only relatively small size copy paper such as 4 or A4 is used intensively, a toner image is formed in the area of the photoreceptor corresponding to the difference between the maximum size that can be copied, for example A3. Opportunities will be almost gone.

By the way, when a blade cleaning method is adopted as a photoconductor cleaning method, the toner adhering to the photoconductor is scraped off with a cleaning blade, but at this time, the lubricant contained in the toner is removed from the photoconductor. This ensures smooth sliding between the cleaning blade and the cleaning blade, prevents wear on the cleaning blade's cutting edge, and ensures uniform and smooth contact with the photoreceptor to reliably scrape off toner, providing a cleaning effect. .

For this reason, as described above, if an area is formed on the photoreceptor over a long period of time in which there is no opportunity for a toner image to be formed, the lubricating effect of the toner between the photoreceptor and the cleaning blade disappears in this area. The cutting edge of the cleaning blade may be damaged or the surface of the photoreceptor may be damaged, resulting in, for example, horizontal lines appearing on the copy, making it impossible to obtain good copies from now on.

Therefore, as a means to solve such problems,
Immediately before stopping the machine after copying, the power to the charger and charge removal lamp are turned off at the same time.At the same time as the charger and charge removal lamp are turned off, the magnet roll of the developer is driven for a predetermined time, thereby reducing the width of the photoreceptor. proposed a method for improving cleaning performance by forming a toner image lubricating area with toner attached over the entire length (Japanese Patent Application Laid-Open No. 60-194-484).
Publication No.).

According to this method for improving cleaning performance, a toner image is always formed over the entire width of the photoconductor immediately before the copying machine stops, and by scraping this toner image with the cleaning blade, the toner image is formed across the entire width of the photoconductor and the cleaning blade. The lubricant in the toner is spread over the entire length, achieving the same effect as periodically supplying lubricant, and making it possible to obtain good copies over a long period of time.

[Problems to be Solved by the Invention] However, in the cleaning performance improvement method described above, a toner image lubricated area with a width corresponding to the distance between the charger and the static elimination lamp is formed, and this toner image If the lubrication area becomes too large, an excessive amount of toner will adhere, which may cause problems such as an increase in the amount of recovered toner, dirt inside the machine, and even insufficient supply of toner to the developer. After being stopped, the magnet roll must be driven again for a predetermined period of time, which not only imposes an extra rotational load on the magnet roll, but also poses a risk that secondary failures may occur due to this load fluctuation.

Therefore, an object of the present invention is to improve the previously proposed method for improving the cleaning performance of a copying machine, and to provide a method for improving the cleaning performance of a copying machine that does not have the above-mentioned problems.

[Means for Solving the Problems] That is, the present invention is a copying machine that is capable of using copy paper of multiple sizes and that employs a blade cleaning method as a photoconductor cleaning method.
In a method for improving cleaning performance in which a toner image lubrication area with toner adhered to the photoreceptor is formed over the entire length of the photoreceptor in the width direction immediately before stopping a multi-machine, the off-timing of the static elimination lamp is delayed by a predetermined period of time from the off-timing of the charger. A method for improving the cleaning performance of a copying machine by forming a toner image lubrication area.

In the present invention, the off-timing of the static elimination lamp and the off-timing of the charger can be controlled with high accuracy using, for example, a timer or a delay circuit, and thereby the width dimension on the photoreceptor can be accurately controlled. A charged region can be formed.

The charged area thus formed on the surface of the photoreceptor is then developed with a developing device and becomes a toner image lubricated area with toner attached. At this time, the amount of toner adhering to the photoreceptor is This can be easily controlled by controlling the width of the charged area, so there is no need for special control to reduce the amount of toner adhesion compared to normal image forming, and it is possible to turn off the developing device drive. The timing can be freely selected after the charged area for forming the toner image lubricating area has been charcoalized and does not adversely affect the copied image or the like.

[Function] In the method for improving the cleaning performance of a copying machine according to the present invention, the width dimension of the toner image lubricated area formed on the surface of the photoreceptor is controlled by the off timing of the charger and the static elimination lamp. The amount of toner that adheres can be controlled by the width dimension of the toner image lubricating area, and the off-timing of the driving of the developing device can also be set after the toner image lubricating area is formed.

[Example] Hereinafter, the method of the present invention will be specifically explained based on the example shown in the attached drawings.

FIG. 1 is an explanatory diagram schematically showing the internal structure of a copying machine to which the cleaning performance improvement method of the present invention is applied, and which can use copy paper of multiple sizes.
A platen cover 1, an exposure lamp 2 which is movable back and forth in the directions of arrows a and b and which illuminates a document (not shown) placed on the bottom side of the platen cover 1, and reflected light from the document passes through an optical path 3 and is irradiated with the exposure lamp 2. A photoreceptor drum 4 is exposed to light by the photoreceptor drum 4, a charger 5 is disposed around the photoreceptor drum 4 and forms a charged area on the surface of the photoreceptor drum 4, and a The charged area is exposed to light reflected from the document to form an electrostatic latent image, and then the electrostatic latent image is formed, and then the electrostatic latent image is formed. A developing device 8 that develops the image to form a toner image, a transfer device 10 consisting of a transfer corotron and a peeling corotron that transfer the toner image onto copy paper conveyed from a paper tray 9, and a photosensitive drum 4 after transfer. A cleaner 12 that cleans the surface of the photoreceptor drum 4 by scraping off residual toner remaining on the surface with a cleaning blade 11, a conveyance device 14 that conveys the copy paper onto which the toner image has been transferred by the transfer section 10, and this conveyance device. A fixing device 15 for fixing the toner image on the copy paper conveyed by 14 is provided.

In this embodiment, the charger 5, the charge eliminating lamp 6, and the magnet roll 7 of the developing device 8 are arranged around the photosensitive drum 4 with the charge eliminating lamp 6 as a reference. are spaced apart by an angle θ1, and magnet rolls 7 are spaced apart by an angle θ2, and the photosensitive drum 4 has an angular velocity of θ0/S.
The charger 5 and the static elimination lamp 6 are used when stopping the machine after copying is completed.
The off-timing of each of the magnetic rolls 7 of the developing device 8 is set to the off-timing t of the charger 5 by means such as a delay circuit, as shown in the timing chart of FIG. The off-timing of the static elimination lamp 6 is set to be jISeC, and the off-timing of the magnet roll 7 is set to be 12 sec later. Note that the settings of tl and t2 at this time are set so as to satisfy the following conditions: 1l-1o<θ1/θ0 and t2-to>θ2/θO.

Therefore, in this embodiment, the width dimension (angle θ,) of the toner image lubrication area A to which toner is attached, which is formed over the entire length of the photoreceptor drum 4 in the width direction immediately before stopping the machine after copying is completed, is θ. , = (θ1− (tl−t□ )θ0), and by appropriately setting 11 within the range of the above setting conditions for t1, the width dimension (angle θ,) of the toner image lubrication area A is adjusted. be able to.

[Effects of the Invention] According to the method for improving the cleaning performance of a copying machine of the present invention,
Immediately before stopping the copying machine, a toner image lubricating area is always formed across the entire length of the photoreceptor in the width direction, so the lubricant in the toner can be supplied between the photoreceptor and the cleaning blade in contact with its surface. This not only prevents damage to the edge of the cleaning blade and makes copies with good image quality over a long period of time, but also controls the width of the toner image lubrication area by adjusting the off timing of the charger and static elimination lamp. Therefore, the amount of toner adhering to this toner image lubrication area can be controlled by the width dimension of the toner bath lubrication area, and if this toner image lubrication area becomes too large, the amount of toner adhesion will be excessive, and the amount of collected toner will be reduced. This eliminates problems such as an increase in water, dirt inside the machine, and insufficient supply of toner to the developer, and the timing for turning off the drive of the developer can be set after the toner image lubrication area is formed. It is possible to prevent an extra load caused by once stopping the developing device and then driving it again for a predetermined period of time, as well as secondary troubles caused by this load fluctuation.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of the interior of a copying machine to which the method for improving cleaning performance of the present invention is applied, and Fig. 2 shows the arrangement of the charger, the static elimination lamp, and the magnet roll of the developer around the photoreceptor drum. The explanatory diagram shown in FIG. 3 is a timing chart showing the relationship between the off timing of the charger, the static elimination lamp, and the magnet roll of the developing device. Explanation of symbols (4)...Photosensitive drum, (5)...Charger, (6) Static elimination lamp, (A)...Toner image lubrication area

Claims (1)

[Claims] This is a copying machine that can use multiple sizes of copy paper and uses a blade cleaning method to clean the photoconductor, and toner adheres to the entire length of the photoconductor in the width direction immediately before stopping the machine after copying is complete. A method for improving cleaning performance of a copying machine, the method comprising: forming a toner image lubricated area by delaying the off timing of a static elimination lamp by a predetermined period of time from the off timing of a charger. .