JP2530715B2 - Electrophotographic equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrophotographic apparatus.

[Prior Art] FIG. 3 shows a general structure of a conventional electrophotographic apparatus. Reference numeral 1 denotes a drum-shaped image bearing member rotatably provided. Around the image carrier 1, a charger 2 that evenly charges the surface of the image carrier 1, a laser beam is applied to the charged surface of the image carrier 1 based on print data, and electrostatic latent images are generated. An exposure unit 3 for forming an image, a developing device 4 for adhering toner (developer) to the image carrier 1 on which the electrostatic latent image is formed and developing the image carrier 1.
A transfer device 5 for transferring the toner image formed on the image carrier 1 onto the sheet 9 and a static eliminator 6 for neutralizing the image carrier 1 charged after the transfer are sequentially arranged.

By the way, if toner or paper dust of paper remains or adheres to the image carrier 1 after the transfer, a printing surface of the paper 9 to be printed next is partially darkened and a printing failure often occurs. Therefore, the electrophotographic apparatus is provided with cleaning means for cleaning the image carrier 1 after transfer.

Conventionally, as a cleaning means, development and image carrier 1
Cleaning means for cleaning the surface, that is, toner that is provided integrally with the developing device 4 and performs development in cooperation with the developing device 4 and that remains on the image carrier 1.
There is known a magnetic cleaning unit 10 configured to collect 12 in the developing device 4 by a magnetic action and clean the image carrier 1.

As the cleaning means, as shown in FIG. 4, there is also known a mechanical cleaning means 20 in which a blade 22 is brought into contact with the surface of the image carrier 1 to scrape residual toner off the surface and store it in a waste toner storage 23. Has been.

Since the mechanical cleaning means 20 scrapes off the residual toner directly by the blade 22, it is possible to perform good cleaning for a long time, but the blade 22 vibrates or the contact pressure becomes excessive during cleaning. Carrier 1
However, there is a drawback that the surface of the is easily scratched and it is difficult to maintain good print quality.

On the other hand, the magnetic cleaning unit 10 tends to be more complicated in control than the mechanical cleaning unit 20, but since the residual toner can be collected and reused without contacting the image carrier 1, it can be used in a recent electrophotographic apparatus. As the cleaning means, a large number of magnetic cleaning means 10 are selected and used.

In the electrophotographic apparatus, the image carrier 1 rotates twice to perform development and cleaning.
There are also those in which development and cleaning are carried out by rotating once (see, for example, JP-A-59-133573).

[Problems to be Solved by the Invention] When the residual toner adheres strongly to the image carrier 1, even if the magnetic cleaning unit 10 cleans the image carrier 1, the cleaning ability is insufficient. Therefore, the residual toner cannot be removed, and the toner may cause printing failure such as partial darkening of the printing surface of the paper 9. In particular, magnetic cleaning means 10
However, if the cleaning performance deteriorates due to use and the cleaning ability decreases, the above-mentioned printing failure easily occurs.

On the other hand, the magnetic cleaning means 10 cannot be adjusted due to its structure when the electrophotographic apparatus is continuously operated.

Therefore, in order to eliminate the above print failure,
It is necessary to interrupt the operation of the apparatus and adjust the magnetic cleaning means 10 to enhance the cleaning ability, which lowers the printing efficiency. Therefore, it is conceivable to adjust the magnetic cleaning means 10 from the beginning so that the cleaning ability is maximized, but this will accelerate deterioration and shorten the service life.

An object of the present invention is to provide an electrophotographic apparatus capable of stably cleaning an image carrier without damaging the image carrier for a long period of time and preventing deterioration of print quality and printing efficiency.

[Means for Solving the Problems] According to the present invention, the image carrier is cleaned by a cleaning unit that can perform development and cleaning, and the mechanical cleaning unit is operated automatically and intermittently to clean the cleaning unit. It is configured to supplement the ability and perform stable cleaning over a long period of time. Further, when printing failure occurs due to insufficient cleaning, the mechanical cleaning means is immediately operated to eliminate the insufficient cleaning.

That is, the present invention has a cleaning means for developing and cleaning the surface of the image bearing member, and a mechanical cleaning means formed by including a blade for contacting the surface of the image bearing member to remove the developer. Then, after printing a set number of sheets, an automatic control means is provided to bring the blade of the mechanical cleaning means into contact with or separate from the surface of the image carrier to supplement the cleaning ability of the cleaning means. An operation pause means for gradually lengthening the operation time in a state where the contact and the separation from the image carrier are repeated at a predetermined time interval and the pause time is constant,
During the rest period, the blade is brought into contact with the image carrier according to an arbitrary command signal.

[Operation] In the present invention having the above-described configuration, the image carrier is cleaned by the cleaning unit, and the automatic control unit automatically moves the blade of the mechanical cleaning unit toward and away from the image carrier to perform auxiliary cleaning. Done,
The cleaning ability of the cleaning means is supplemented.

At this time, the operation pause means constituting the automatic control means repeats contact and separation of the blade with the image carrier at predetermined time intervals, and gradually lengthens the operation time while keeping the pause time constant. As a result, the image carrier can be supplementarily cleaned by the blade at the optimum time interval, and the cleaning ability of the cleaning means can be supplemented without damaging the surface of the image carrier.

Further, in the case where printing failure occurs due to insufficient cleaning, an optional command signal is output to the automatic control means so that the occasional operation means constituting the automatic control means
The blade is brought into contact with the image carrier even during the rest period,
Auxiliary cleaning is performed to eliminate the lack of cleaning.

[Embodiment] An embodiment of the present invention will be described with reference to the drawings.

In this embodiment, as shown in FIG. 1, a developing means and an image bearing body as a cleaning means and a process means comprising an image bearing body 1, a charging device 2, an exposing device 3, a developing device 4, a transfer device 5 and a static eliminator 6. 1 cleaning means 10 for cleaning the surface.

The same components as those shown in FIGS. 3 and 4 are designated by the same reference numerals, and the description thereof will be omitted or simplified.

Here, the magnetic cleaning means 10 is formed so as to cooperate with the developing device 4 to alternately perform the developing action and the cleaning action at predetermined time intervals t, as shown in FIG. Here, the predetermined time t is selected so as to correspond to the time required for the image carrier 1 to make one rotation.

Further, the electrophotographic apparatus is provided with a mechanical cleaning means 20 to supplement the cleaning ability of the magnetic cleaning means 10.

In this embodiment, the mechanical cleaning means 20 is
The blade 22, the lever 24, the solenoid 25, and the like are included, and the blade 22 is formed so as to be in contact with and away from the surface of the image carrier 1.

More specifically, the blade 22 is provided at the lower end of a rotatably provided lever 24, so that the blade 22 comes into contact with or separates from the image carrier 1 by rotating the lever 24. Has been formed. The blade 22 is formed in a plate shape or a brush shape. A solenoid 25 is connected to the lever 24 to rotate the lever 24 to bring the blade 22 into contact with or away from the image carrier 1.

Here, the solenoid 25 is drive-controlled by the automatic control means 30 described later via the drive circuit 26. Further, the blade 22 is normally separated from the image carrier 1 by the cooperation of the lever 24 and the spring 27, and the solenoid 25 is driven to rotate the lever 24 counterclockwise to move the image carrier. It is formed so as to come into contact with 1 at a predetermined pressure. In the present embodiment, the blade 22 is not in constant contact with the image carrier 1 and does not damage the image carrier 1.
The contact pressure of the blade 22 is set to be strong so that the residual toner that cannot be removed by 10 can be easily scraped off.

Further, in the electrophotographic apparatus, the mechanical cleaning means 20 is operated at appropriate time intervals so that the magnetic cleaning means is operated.
The blade 22 is attached to the image carrier 1 so as to supplement the cleaning ability of 10 and realize stable cleaning over a long period of time.
An automatic control means 30 for contacting / separating from the surface of the is provided. Here, in this embodiment, the automatic control means 30 is a part of the automatic control device (CPU, RO
It is formed using M, RAM, operation panel, timer, etc.).

The automatic control means 30 is composed of operation stopping means and occasional operation means.

The operation stopping means is formed so as to repeat contact and separation of the blade 22 with the image carrier 1 at predetermined time intervals. That is, the operation pause means drives the solenoid 25 via the drive circuit 26 to keep the blade 22 for a predetermined time (pause time t ₀ , t ₁ , t ₂ , t ₃ ) as shown in FIG. 2 (c). ...) at predetermined intervals for each predetermined time (operating time T ₀ , T ₁ , T ₂ , T ₃ ...)
The ROM has a built-in auxiliary cleaning program that involves touching the.

Here, the rest time and the operation time are selected so that the residual toner that cannot be completely collected by the magnetic cleaning means 10 can be scraped off without damaging the surface of the image carrier 1 by the blade 22. . In the present embodiment, the respective pause times t ₀ , t ₁ , t ₂ , t _3, ... Are made constant as shown in FIG. 2 (c), and are set as the operating time required to print 600 sheets of paper. In addition, each operating time T ₀ , T ₁ ,
T _2, T ₃ ... and the constant is set to both the image bearing member 1 is to take time over one rotation of less (operating time required for printing 2 sheets of paper in this embodiment). The numerical values selected as the pause time and the operation time are stored in the RAM of the automatic control means 30 via the operation panel. Note that these numerical values can be set and changed via the operation panel.

Further, the occasional operation means constituting the automatic control means 30 is configured so that the solenoid 25 operates even when the blade 22 is separated from the image carrier 1 when the arbitrary command signal is interrupted and the blade 22 is separated from the image carrier 1.
The ROM has a built-in program for driving the blade to bring the blade 22 into contact with the image carrier 1 for a predetermined time Tr. In the present embodiment, the CPU of the automatic control means 30 gives priority to the execution of the auxiliary cleaning program based on an arbitrary command signal input via a key (for example, the key 31) provided on the operation panel, and the solenoid 25 Is driven to bring the blade 22 into contact with the image carrier 1 for a predetermined time Tr, as shown by the chain double-dashed line in FIG. 2 (c).

 Next, the operation will be described.

When a start command is issued from the operation panel, the automatic control device controls the rotation of the image carrier 1 and the drive control of the charger 2, the exposure unit 3, the developing device 4 and the like in a predetermined procedure,
The toner image is developed on the image carrier 1, the toner image is transferred onto the paper 9 fed by the transfer device 5, and after the transfer, the charge eliminator 6 is driven to remove the residual charge of the image carrier 1. I do.

Thus, at the end of the developing cycle, the automatic control device (30) stops the driving of the charging device 2, the exposure unit 3, the developing device 4, the transfer device 5, and the like, while controlling the rotation of the image carrier 1. The magnetic cleaning means 10 is caused to perform a cleaning action for a predetermined time t, and the magnetic powder toner 12 remaining on the image carrier 1 is collected in the developing device 4.

In this way, printing is continuously performed while alternately performing the developing cycle and the cleaning cycle. By the way, during operation, the operation pause means constituting the automatic control means 30 drives the solenoid 25 to move the blade 22 to the image carrier 1 when the operation time reaches the pause time t ₀ (that is, printing of 600 sheets of paper).
To the operating time T ₀ (that is, printing of two sheets of paper). As a result, the auxiliary cleaning is performed by the blade 22 and the residual toner that cannot be removed by the magnetic cleaning unit 10 is scraped off.

In the following, the operation pause means is configured such that the operation time is the pause time t ₁ , t ₂ , t ₃
, The blade 22 is brought into contact with the image carrier ₁ for each operation time T ₁ , T ₂ , T _3, ... For auxiliary cleaning. As a result, the image carrier 1 is stably cleaned over a long period of time.

At this time, as the operating time becomes longer, the amount of the adhered residual toner and the like increases and the cleaning ability of the cleaning means 10 decreases. Therefore, as shown in FIG. (Corresponding to printing), and the operating times T ₀ , T ₁ , T ₂ , T ₃ ... Are gradually increased (for example, T ₀ is equivalent to printing two sheets of paper, and T ₁ , T ₂ , T ₃ ...
It is selected so that it can print 3,4,5 sheets.

By the way, when the operator presses the key 31 on the operation panel of the automatic control means 30 when a printing defect such as blackening of the printing surface of the paper occurs due to insufficient cleaning during operation of the apparatus, the automatic control means 30 is operated through the panel. An arbitrary command signal is input to the automatic control means 30, and the occasionally operating means that constitutes the automatic control means 30 drives the solenoid 25 even during the rest period of the mechanical cleaning means 20, so that 2 in FIG. 2 (c). As indicated by the dotted line, the blade 22 is brought into contact with the image carrier 1 for a predetermined time Tr to perform auxiliary cleaning. As a result, the cleaning ability can be quickly increased without interrupting the operation.

Therefore, according to this embodiment, the cleaning means 10 for developing and cleaning the surface of the image carrier 1 and the blade 22 for contacting the surface of the image carrier 1 and removing the toner (developer) are formed. And the blade 22 of this mechanical cleaning means 20.
Control means for bringing the surface of the image carrier 1 into contact with and separating from
Since the image carrier 1 is provided with the cleaning means 10, the cleaning means 10 cleans the image carrier 1, and the blade 22 of the mechanical cleaning means 20 automatically and intermittently supplements the cleaning ability of the cleaning means 10. You can Therefore, it is possible to perform stable cleaning over a long period of time and prevent deterioration of print quality and print efficiency.

Further, the operation pause means constituting the automatic control means 30 is such that the contact and separation of the blade 22 with respect to the image carrier 1 is repeated at predetermined time intervals and the operation time is gradually lengthened with the pause time kept constant. Since it is formed as described above, auxiliary cleaning can be performed by bringing the blade 22 into contact with the image carrier 1 at an optimum time interval, and compensating for a decrease in cleaning ability without damaging the surface of the image carrier 1. You can

Further, since the operation means constituting the automatic control means 30 is formed so as to bring the blade 22 into contact with the image carrier 1 by an arbitrary command signal even during the rest period of the mechanical cleaning means 20, printing due to insufficient cleaning is performed. When a defect occurs, by inputting an arbitrary command signal to the automatic control means 30, the occasional operation means that constitutes the automatic control means 30 can quickly eliminate the insufficient cleaning by performing auxiliary cleaning by the blade 22. You can As a result, it is possible to perform stable cleaning over a longer period of time.

Further, in view of the fact that the blade 22 is not always in contact with the image carrier 1, the contact pressure of the blade 22 with respect to the image carrier 1 is set to be strong, so that the residual toner that cannot be removed by the cleaning unit 10 is used. Can be easily scraped off by the blade 22, and from this point as well, stable cleaning can be performed over a long period of time.

Further, since the blade 22 is driven by the solenoid 25 via the lever 24, it is possible to reliably perform auxiliary cleaning with a simple structure, and from this point as well, stable cleaning can be performed over a long period of time. it can.

Further, since most of the residual toner is collected and reused by the cleaning means 10, it is not necessary to make the waste toner storage portion 23 of the mechanical cleaning means 20 large, which does not hinder the downsizing of the electrophotographic apparatus.

As shown in FIG. 2A, the operating time (T ₀ , T ₁ ,
T ₂ , T ₃ …) is kept constant, and the pause time (t ₀ , t ₁ , t ₂ , t ₃ …) is gradually shortened (for example, t ₀ is equivalent to printing 600 sheets of paper, and t ₁ , t ₂ , t ₃ ... Can correspond to printing of 400, 300, 200 ... sheets.

As described above, even when the pause time and the operation time are selected, the automatic operation means 30 which constitutes the automatic control means 30 on the basis of an arbitrary command signal as shown by a two-dot chain line in FIGS. 2 (a) and 2 (b). Can perform auxiliary cleaning by bringing the blade 22 into contact with the image carrier 1 for a predetermined time Tr even during a rest period in which the blade 22 is separated from the image carrier 1.

Further, the key 31 provided on the operation panel is used as a means for inputting an arbitrary command signal to the automatic control means 30,
A switch (not shown) for outputting an arbitrary command signal is provided in the vicinity of the lever 24 where the printed result can be directly observed, and the arbitrary command signal is input to the automatic control means 30 via the switch. Good. Thereby, it is possible to press the switch while observing the print result, and if it is found from the print result that cleaning is insufficient, the operator can immediately press the switch to perform auxiliary cleaning with the blade 22, Print defects can be eliminated more quickly.

At this time, the arbitrary command signal may be input to the automatic control means 30 only while the switch is manually pressed. Alternatively, the switch may be mechanically locked when pushed by hand so that an arbitrary command signal is continuously input.

[Advantages of the Invention] According to the present invention, a cleaning means for developing and cleaning the surface of an image bearing member and a mechanical cleaning means including a blade are provided side by side, and a blade is imaged after printing a set number of sheets. An automatic control means for contacting / separating the surface of the carrier is provided, and this automatic control means repeats contact and separation of the blade with the image carrier at a predetermined time interval and maintains the operation time in a state where the rest time is constant. Since it is composed of an operation pausing means for gradually lengthening and an operating means for bringing the blade into contact with the image carrier by an arbitrary command signal during the pausing period, the image carrier is not damaged for a long period of time. It is possible to perform stable cleaning and prevent deterioration of print quality and print efficiency.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a main part of one embodiment of the present invention, and FIG. 2 is a timing chart for explaining the operation. FIG. 3 and FIG. 4 are schematic views showing a main part of a conventional electrophotographic apparatus. FIG. 3 shows only a magnetic cleaning device as a cleaning means, and FIG. 4 shows only a mechanical cleaning device as a cleaning means. Is the case. 1 ... Image carrier, 4 ... Developing device, 10 ... Cleaning means, 20 ... Mechanical cleaning means, 22 ... Blade, 30 ... Automatic control means.

Claims (1)

(57) [Claims] 1. A cleaning means for developing and cleaning the surface of an image bearing member, and a mechanical cleaning means formed by including a blade for coming into contact with the surface of the image bearing member to remove the developer. After the set number of sheets of paper have been printed, an automatic control means for supplementing the cleaning ability of the cleaning means by bringing the blade of the mechanical cleaning means into contact with or away from the surface of the image carrier is provided. The operation pause means for gradually increasing the operation time in a state where the contact time and the separation from the image carrier are repeated at a predetermined time interval and the pause time is constant, and the blade is operated by an arbitrary command signal during the pause time. An electrophotographic apparatus comprising: an operating unit that contacts the image carrier at any time.