JPH11272137A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stabilized image by preventing the degradation of an image by accurately setting the timing of filming removing operation by executing the filming removal operation again when potential on an image carrier is set to be equal to or above a predetermined value. SOLUTION: A surface potential meter 25 as a measuring means to measure the potential on a photoreceptor 1 is arranged. A latent image to be a reference is formed on the photoreceptor 1, and the change of the potential with time is sampled by taking the potential as a reference value, and the forming state of a filming material is judged by comparing them. Then, the potential of the latent image on the photoreceptor 1 is measured by the surface potential meter 25 after a filming removing device 5 removes filming, and if a measured value is raised to be equal to or above specified value by comparing it with the reference value previously set, the filming removal operation is executed again by the filming removal device 5. Thus, the timing of the filming removal operation is set to be accurate without being caused by filming formation by the operation condition of an image forming device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electronic copier, a printer, a facsimile, and the like.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus such as an electronic copying machine, a printer, and a facsimile,
The filming substance may adhere to the image carrier in a film form. The filming may be caused by, for example, a developer carrier or NO generated by corona discharge.
x (nitrogen oxide) and the like on the mechanism of the image forming apparatus, and, for example, those depending on the use environment conditions such as the type of transfer material (paper type, additives contained in paper), temperature, and operating conditions. Divided. Since this filming substance causes deterioration of the image quality of the toner image, it is better to remove it at an early stage. Therefore, conventionally, the filming substance attached to the image carrier is removed by a filming removal brush,
The image quality of the toner image is prevented from deteriorating.

Conventionally, as a timing of removing the filming, as disclosed in Japanese Patent Application Laid-Open No. 2-191980, the number of processed sheets at which an image is adversely affected by the filming is estimated, and this estimated value is set in advance in image formation. When the number of processed sheets reaches the set expected value, the filming removal brush is operated by manually turning on a main switch again or pressing an operation input key.

[0004]

However, the above-mentioned filming formation is largely caused by the above-mentioned use environment conditions. Before the value reaches the expected value, filming may affect the image.
That is, the effect of the filming removal changes depending on the degree of filming fixation of the image carrier, the degree of brush deterioration such as falling of the brush of the scraping brush, and hair loss. This allows
Under the same operating conditions every time, filming cannot be removed at an appropriate time for filming removal, and thus there is a problem that a stable image cannot be obtained.

[0005] The effect of removing filming is judged by the user looking at the image. However, if the user does not notice any abnormality in the image, there is also a problem that a large number of abnormal images appear. Yes (miscopy, misprint increase).

Accordingly, it is an object of the present invention to provide an image forming apparatus capable of obtaining a stable image.

[0007]

According to a first aspect of the present invention, there is provided an image carrier on which an electrostatic latent image is formed, and a filming removing means for scraping off a filming substance formed on the image carrier. A measuring means for measuring a potential of a latent image on an image carrier, and an image forming apparatus comprising a control means for performing various controls of the apparatus, after the filming removing means removes filming, the measuring means The potential of the latent image on the image carrier is measured, and when the measured value is higher than a predetermined reference value by a predetermined value or more, the control unit re-fills the filming removing unit with the film. It is characterized by performing a mining removal operation.

According to the first aspect of the present invention, when the potential on the image carrier becomes a predetermined value or more, the filming removing operation is performed again. Since the potential measurement is based on the potential measurement as described above, the timing of the filming removing operation can be accurately determined without being caused by the filming formation due to the operation conditions of the image forming apparatus. In addition, since filming can be removed at an appropriate time, deterioration of an image due to filming can be prevented, and a stable image can be obtained. Further, since the filming removal operation is performed again, the filming removal failure is prevented.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a notifying means for notifying the state of the apparatus, and the control means controls the number of times of the filming removing operation by the filming removing means. When the number of times equal to or more than a predetermined number is counted, the operation of the apparatus is stopped, and the notification unit is notified.

According to the second aspect of the present invention, the upper limit (predetermined number) of the number of repetitions of the filming removing operation is set, and when the predetermined number or more is counted, the operation of the apparatus is stopped. Since the notification unit is notified, it is possible to determine the limit time of the filming removal capability of the filming removal unit. In addition, since the limit of the filming removal ability can be determined, the user can take measures such as maintenance, so that the filming removal means can always be in a good state.

According to a third aspect of the present invention, there is provided an image carrier on which an electrostatic latent image is formed, filming removing means for scraping off a filming substance formed on the image carrier, and an image carrier on the image carrier. In an image forming apparatus including a measuring unit for measuring a latent image potential and a control unit for performing various controls of the apparatus, after the filming removing unit removes filming, the measuring unit removes a latent image on the image carrier. The image potential is measured, and when the measured value has increased by a predetermined value or more compared to a preset reference value, the control unit extends the operation time of the filming removing unit from the previous time. It is characterized by the following.

According to the third aspect of the present invention, when the potential of the image carrier exceeds a predetermined value, the filming removal operation time is extended from the previous time, so that the image deterioration due to filming is prevented. And a stable image can be obtained. Further, since the time for the filming removal operation is extended, defective removal of the filming is prevented.

According to a fourth aspect of the present invention, in accordance with the third aspect of the present invention, there is provided a notifying means for notifying the state of the apparatus, and the control means controls a removal time of the filming removing operation by the filming removing means. When the extension time is extended for a predetermined time or more, the operation of the apparatus is stopped and the notification means is notified.

According to the fourth aspect of the present invention, since the upper limit value (predetermined time) of the filming removing operation time is set, it is possible to be notified when the removing capability of the filming removing means is limited. Further, the notification can be made at an appropriate time, and the user can take measures such as maintenance at that time, so that the filming removing means can always be kept in a good state.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram schematically showing a copying machine (image forming apparatus) 30 to which the present invention is applied. First, the overall configuration and operation will be briefly described. The copying machine 30 generally includes a photoconductor 1 (image carrier), a charger 3, an imaging optical system 4, a filming removing device (filming removing unit) 5, a developing device 6, and a transfer device 7. , A cleaning device 8, a paper feeding device 9, and a fixing device 11.

The photosensitive member 1 is wound around a driving roller 2a and a plurality of other supporting rollers 2, and is driven to run in the direction of arrow A by the rotation of the driving roller 2a. At this time, the photoreceptor 1 is uniformly charged to a predetermined polarity by the charger 3 constituted by a corona discharger. The charged photoconductor 1 is image-exposed by the imaging optical system 4, and a predetermined electrostatic latent image is formed on the photoconductor 1. This electrostatic latent image is visualized as a toner image when passing through the developing device 6.

The developing device 6 includes three developing sleeves 20.
Are arranged, and a magnet 21 is immovably arranged inside each developing sleeve 20. These developing sleeves 20
Is rotationally driven, so that the developer is carried and conveyed on each developing sleeve 20. As this developer,
At least a part of the magnetic material is used. For example, a two-component developer having a toner and a carrier or a one-component developer not containing a carrier is used. Regardless of which developer is used, the magnetic brush D is formed by the action of the magnetic force of the magnet 21 when the developer is carried on each developing sleeve 20 and transported. When the toner in the magnetic brush D adheres to the electrostatic latent image formed on the photoconductor 1, the electrostatic latent image is visualized as a toner image.

On the other hand, the transfer paper is fed from the paper feeding section 9 to the photosensitive member 1.
And the toner image on the photoreceptor 1 is transferred onto the transfer paper by the discharging action of the transfer device 7 composed of a corona discharger. Thereafter, the transfer paper is separated from the photoreceptor 1 while being subjected to the discharging action of the separation device 7 a also constituted by a corona discharger, and the separated transfer paper is conveyed to the fixing device 11 by the conveyance belt 10.

When the transfer sheet passes through the fixing device 11, the toner image on the transfer sheet is fixed on the transfer sheet and discharged outside the apparatus. Further, the residual toner remaining on the photoconductor 1 after the transfer of the toner image is cleaned and removed by the cleaning device 8. Thus, the photoconductor 1 is used repeatedly.

When the above-described image forming operation is repeatedly performed, a filming substance adheres to the photoreceptor 1. The filming substance includes, for example, fine powder of toner and fine powder of carrier in developer, talc and other chemical components in transfer paper, NOx formed by O ₃ (ozone) released from a corona discharger, and the like. Is formed by adhering to the photoreceptor 1. If the filming substance is left untouched, the image quality of the toner image deteriorates. Therefore, it is desirable to remove the filming substance at an early stage. Since it is difficult to remove the filming substance by the cleaning device 8, the filming removing device 5 is disposed between the driving roller 2a and the developing device 6 separately from the cleaning device 8.

The film removing device 5 has a brush roller 22, and the brush roller 22 is a film removing brush 12 made of conductive metal fibers woven into a base cloth.
And a roller-shaped core material around which the base fabric is wound. The brush roller 22 is supported so as to be able to freely contact and separate from the photoconductor 1, and is configured to be driven to rotate in the direction of the arrow in the figure. A backup roller 13 is disposed at a position facing the brush roller 22 with the photoconductor 1 interposed therebetween.

Drive roller 2a and filming removing device 5
A surface voltmeter 25 is arranged between the photoconductor 1 and the photoconductor 1 as measuring means for measuring the potential on the photoconductor 1. In the present embodiment, the lines of electric force generated from the surface potential on the photoconductor 1
Although an electrode in which a potential is induced in the electrodes in the surface voltmeter 25 is used, other methods may be used as long as the measuring means has the same purpose of measuring the potential of the surface of the photoconductor 1.

Here, the relationship between the filming lamination amount and the surface potential will be described. FIG. 3 is a graph in which the vertical axis indicates the amount of attenuation of the surface potential of the photoconductor 1, and the horizontal axis indicates the amount of filming stacked on the photoconductor 1. FIG. 4 is a graph in which the vertical axis indicates the surface potential of the photoconductor 1 and the horizontal axis indicates the filming amount.

As is clear from the graph of FIG.
As the filming lamination amount increases, the attenuation amount of the surface potential decreases. That is, if the filming substance is the photoconductor 1
When formed on the surface, the surface potential is hardly attenuated by light irradiation during exposure, and the amount of attenuation further decreases as the filming stack amount (thickness) increases.

As a result, as can be seen from FIG. 4, the potential on the photosensitive member 1 after the exposure rises, and the transferred image has, for example, a black portion with no characters or pictures. Deterioration appears remarkably.

A reference latent image is formed on a photoreceptor,
Using the potential as a reference value (V1), a change in the potential over time is sampled, and these are compared to determine the formation state of the filming substance. In the case of the copying machine 30 of the analog optical device, the reference image is, for example, a white-painted one so that the surface potential can be sufficiently attenuated in a portion exposed and irradiated in a non-image area on the transfer paper. What is necessary is just to provide and provide a member with high light reflectance, such as white paper and white paper. Further, in the case of the copying machine 30 as a digital optical device, for example, a laser, an LED (light emitting diode), or the like may be kept constant in a non-image area at a certain pattern width as in the above-described case.

As shown in FIG. 2, the copying machine 30
The apparatus includes a CPU (microcomputer) 31 which is a control unit for controlling the entire copying machine 30. A ROM (memory) 32 in which an execution program is written, a RAM (input buffer) 33 in which potential data and the like of a reference image are written, and data is stored by a battery, and an analog signal are replaced with a digital signal for the CPU 31. The A / D converter 34 and the I / O port 35 of the input / output interface are connected by a parallel bus line 36. In addition, a display means (notification means) 40 is connected to the CPU 31.
The display data is sent to the display means 40. The display means 40
Although there is no particular limitation, it is preferable to use an LED or a liquid crystal, and it is preferable to use a parallel bus or a serial communication element to connect to the CPU.

The A / D converter 34 includes a surface voltmeter 2
5 is input. That is, the surface voltmeter 25 converts the measured potential (analog value) to a potential on the order of the TTL signal level and inputs the potential to the A / D converter.

On the other hand, to the I / O port 35, a set sensor 37, which is a means for detecting the attachment / detachment of the photosensitive member 1, is input and connected.
A motor 38 for driving the photoconductor 1 and a motor 39 for driving the filming removing brush 12 are connected to the output.

Next, the operation of the copying machine 30 in the first embodiment based on the above configuration will be described with reference to the flowchart shown in FIG.

First, the reference potential (reference value) V0 of the reference image
Is set in the program. In step S1,
When the copying machine 30 starts performing image formation (print job),
In step S2, a reference image is formed during the image forming operation. In step S3, the potential V of the reference image is formed.
Measure 1.

In step S4, the potential V1 of the reference image measured in step S3 is compared with a preset reference potential V0. Here, the potential V1 of the reference image
Is determined to be higher than the value of the reference potential V0 by a predetermined value a (V1-V0> a). If it is not higher, the process returns to step S1. If it is higher, step S5 is performed.
Proceed to.

In step S5, it is determined whether or not the print job being executed has been completed. If the print job has been completed, the process proceeds to step S6, and if not, the process proceeds to step S7.

At step S7, it is determined whether or not there is a large amount of print job remaining. If there is no large amount of print job remaining, at step S8, the print job is executed as it is, and the process returns to step S5. If a large number of print jobs remain, the flow advances to step S6 to start the filming removal operation. That is, if a large number of print jobs remain, if the filming removal operation is performed after the print job is completed, the image may be adversely affected. Therefore, the filming removal operation is performed with priority. .

In step S6, the photosensitive member 1 and the brush roller 22 of the filming removing device 5 are rotated to
The operation proceeds to the filming removal operation.

In step S9, it is determined whether or not the photosensitive member 1 has been rotated a set number of times (operated for a predetermined time). If not, the process returns to step S6, and if the photosensitive member 1 has been rotated a set number of times. Goes to step S10.

In step S10, the surface potential V2 of the photosensitive member 1 is measured again. Here, to measure again,
Whether the filming removal operation has been completed successfully
This is because it changes depending on the degree of fixation of the filming forming substance and the degree of deterioration of the filming removing brush 12, and it is not known whether the measurement is completed successfully unless the measurement is performed again.

In step S11, the reference potential V0
And the measured value V2 measured in step S10. Here, it is determined whether or not the measured value V2 in step S10 has increased by a predetermined value b (b ≧ 0) or more (V2−V0 ≧ b) from the value of the reference potential V0. Proceed to S12. Then, in step S12, it is recognized that the filming removal has failed, and the process returns to step S6. If it has risen, the process proceeds to step S13. Note that the value of b is preferably set to a level that is larger than the reference potential V0 and does not affect the image.

In step S13, it is determined whether or not a print job remains. If a print job remains, the process proceeds to step S14.
The print job is continued, and the process returns to step S13. Also,
If no print job remains, the control ends. If the threshold potential of the filming removing operation is slightly margined from the level at which the image is affected, there is no problem in removing after the remaining job is completed. It is preferable to secure a margin so that processing of several hundred sheets can be sufficiently performed.

In addition to the above, the timing of the potential measurement of the reference image over time may be set immediately after the completion of the job when the number of processed jobs in one job is small, or, for example, by operating the copier 30 only in the daytime. In the case where the main switch is turned off at night and the number of processed sheets per day is so small that it does not reach the level required for filming removal, it may not be sufficient for the measurement even when the main switch of the device is turned on. is there.

In the first embodiment, when the surface potential of the photosensitive member 1 becomes equal to or more than the predetermined value b, the filming removal operation is performed again, so that the filming can be formed under the operating conditions of the copying machine 30. Since the measurement is based on the measurement of the potential without being caused, the timing of the filming removing operation becomes accurate. As described above, since filming can be removed at an appropriate time, deterioration of an image due to filming can be prevented, and a stable image can be obtained. Further, since the filming removal operation is performed again, the filming removal failure is prevented.

Next, other embodiments of the present invention will be sequentially described. In the description, the same portions as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The operation of the copying machine 30 according to the second embodiment will be described with reference to the flowchart of FIG. 6, but the same operation is performed up to step S12 in FIG. Description is omitted.

In step S21, 1 is further counted in the number-of-times data n of the filming removal operation (n +
1). That is, in step S12, the failure of the filming removing operation is recognized, and the number of failures is counted in step S21. The count data N is sequentially overwritten on the RAM 33.

In step S22, step S21
Is compared with the upper limit value (predetermined number) c of the number of repetitions of the filming removing operation.
If the upper limit c does not count the number of failures or more, the process returns to step S6. Note that the upper limit value c is a value preset in the program, and the value is the number of times that it can be determined that the filming removal effect is not obtained even if the filming removal operation is performed any further.

In step S23, it is determined that the filming cannot be removed. In step S24, the copying operation of the copying machine 30 is stopped. In step S25, the filming removing brush 12, the photosensitive member 1, and the like are replaced. The message prompting maintenance such as
Is displayed and the control is terminated.

In the second embodiment, since the upper limit value c is set, maintenance can be prompted when the scraping ability of the filming removing brush 12 is limited. In addition, since maintenance can be prompted at an appropriate time, the filming removing device 5 and the photoconductor 1 can always be kept in a good state.

Next, a third embodiment of the present invention will be described with reference to the flowchart of FIG. 7. The operation of the copying machine 30 in the third embodiment is the same until step S10 of FIG. The description of the operation up to this point is omitted.

In step S31, step S10
Is compared with the reference potential V0.
Here, the measured value V2 is smaller than the value of the reference potential V0 by a predetermined value d.
It is determined whether or not (d ≧ 0) or more. If it is, the process proceeds to step S34. If it is not, the process proceeds to step S32. The value of the predetermined value d may be set to a level that can hold the image up to the next expected number of filming removal operations. When the predetermined value d is the same as the predetermined value b in the first embodiment, the level is such that the image cannot be held, so that it is preferable to perform the same control as in the first embodiment.

In step S32, it is recognized that the filming removing operation time t is insufficient, and step S3 is performed.
In 3, the filming removal operation time t is extended by the time e (t + e). The time e may be determined based on the time required for the photoconductor 1 to make one rotation.

Thereafter, the copying machine 30 performs the same operation as in step S13 and thereafter in the first embodiment, and ends the control.

In the third embodiment, when the surface potential of the photoreceptor 1 exceeds a predetermined value d, the filming removal operation time is extended by e from the previous time, thereby preventing image deterioration due to filming. Thus, a stable image can be obtained. Further, since the time for the filming removal operation is extended, defective removal of the filming is prevented.

Next, a fourth embodiment of the present invention will be described with reference to the flowchart of FIG. 8. The operation of the copying machine 30 in the third embodiment is the same up to step S33 of FIG. The description of the operation up to this point is omitted.

In step 41, the value (t + e) obtained by extending the time e in step S33 is compared with the upper limit value (predetermined time) T of the time preset in the program. Here, it is determined whether or not the extended value (t + e) is equal to or greater than the upper limit value T. If the extended value (t + e) is equal to or greater than the upper limit value T, the same control as in step S23 and subsequent steps in the second embodiment is performed. If it is not equal to or larger than the upper limit value T, the process returns to step S6 in the first embodiment. The extended time e
Are sequentially overwritten on the RAM 33, and the upper limit value T is a value set in advance in the program. is there.

In the fourth embodiment, since the upper limit value T of the filming removal operation time is set, maintenance can be prompted when the scraping ability of the filming removal brush 12 is limited. In addition, since maintenance can be prompted at an appropriate time, the filming removing device 5 can be used.
And the photoreceptor 1 can always be kept in a good state.

The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the paper of the present invention.

In the present embodiment, the present invention is applied to a copying machine 3
Although applied to 0, for example, the same effect can be obtained even when applied to a printer, a facsimile, or the like.

[0057]

According to the first aspect of the present invention, when the potential on the image carrier becomes a predetermined value or more, the filming removing operation is performed again, so that the timing of the filming removing operation can be accurately determined. That is, deterioration of an image can be prevented, and a stable image can be obtained. In addition, it is possible to prevent filming removal failure.

According to the second aspect of the present invention, the upper limit number (predetermined number) of the number of repetitions of the filming removal operation is set, and when the number of times exceeds the predetermined number, the operation of the apparatus is stopped to notify the user. Since the means is notified, it is possible to judge the limit of the filming removing ability of the filming removing means, and to always keep the filming removing means in a good state.

According to the third aspect of the present invention, when the potential of the image carrier exceeds a predetermined value, the time for the next filming removal operation is extended to prevent image deterioration due to filming. Thus, a stable image can be obtained, and defective removal of filming can be prevented.

According to the fourth aspect of the present invention, since the upper limit value (predetermined time) of the filming removal operation time is set, it is possible to notify when the removal capability of the filming removal means is at its limit, and to perform filming. The removal means can always be kept in a good state.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a copying machine to which the present invention is applied.

FIG. 2 is a control block diagram of the copying machine shown in FIG.

FIG. 3 is a graph showing a relationship between a filming lamination amount and an attenuation amount of a surface potential of a photoconductor.

FIG. 4 is a graph showing a relationship between a filming lamination amount and a surface potential of a photoconductor.

FIG. 5 is a flowchart of an operation of the copying machine according to the first embodiment.

FIG. 6 is a flowchart of an operation of the copying machine according to the second embodiment.

FIG. 7 is a flowchart of the operation of the copying machine according to the third embodiment.

FIG. 8 is a flowchart of an operation of a copying machine according to a fourth embodiment.

[Explanation of symbols]

Reference Signs List 1 photoconductor (image carrier) 5 filming removing device (filming removing means) 25 surface electrometer (measuring means) 30 copying machine (image forming apparatus) 31 CPU (control means) 40 display means (notifying means) b, d Predetermined value c Predetermined number of times T Predetermined time V0 Reference value

Claims (4)

[Claims] 1. An image carrier on which an electrostatic latent image is formed, filming removing means for scraping off a filming substance formed on the image carrier, and measurement for measuring a latent image potential on the image carrier. Means, and an image forming apparatus comprising control means for performing various controls of the apparatus, wherein after the filming removing means removes filming, the measuring means measures a latent image potential on the image carrier, and When the measured value is higher than a predetermined reference value by a predetermined value or more, the control means causes the filming removing means to perform the filming removing operation again. apparatus. 2. An informing means for informing a status of the apparatus,
When the number of times of the filming removing operation by the filming removing means is greater than or equal to a predetermined number, the control means stops the operation of the apparatus and causes the notifying means to notify. Item 2. The image forming apparatus according to Item 1. 3. An image carrier on which an electrostatic latent image is formed, filming removing means for scraping off a filming substance formed on the image carrier, and measurement for measuring a latent image potential on the image carrier. Means, and an image forming apparatus comprising control means for performing various controls of the apparatus, wherein after the filming removing means removes filming, the measuring means measures a latent image potential on the image carrier, and When the measured value has increased by a predetermined value or more compared to a preset reference value, the control means extends the operation time of the filming removing means from the previous time. apparatus. 4. A notifying means for notifying a status of the apparatus,
When the extension time of the removal time of the filming removal operation by the filming removal means is extended by a predetermined time or more, the control means stops the operation of the apparatus and notifies the notification means. The image forming apparatus according to claim 3.