JP2004341004A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that it is very difficult to remove impurities when a lot of impurities adhere to one spot of a photoreceptor drum made of hard material used recently. <P>SOLUTION: In the image forming apparatus, the photoreceptor drum is rotated at specified intervals regardless of image formation after the image formation so as to prevent a lot of impurities from adhering to one spot of the photoreceptor drum. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus having a printing function, such as a copier, a printer, and a multifunction peripheral.
[0002]
[Prior art]
In an electrophotographic printing process, a latent image is formed on the photoconductor drum after the photoconductor drum is uniformly charged by a charger, and then the toner is attached to the latent image to form a visible image on the photoconductor drum. Is formed.
[0003]
When charging the photoreceptor drum, a high voltage is applied to the charger, so that impurities such as NOx are generated around the charger. The impurities adhere to a portion of the photosensitive drum near the charger. The portion of the photosensitive drum to which the impurity adheres cannot be charged or a latent image cannot be formed, and thus the impurity causes a deterioration in the quality of a visible image formed on the photosensitive drum.
[0004]
Conventionally, in order to prevent the quality of a visible image from deteriorating, impurities attached to the photosensitive drum are removed together with the toner by a cleaner that removes excess toner and the like attached to the photosensitive drum. .
[0005]
[Patent Document 1]
JP 09-106216 A
[Problems to be solved by the invention]
Some of the impurities generated during charging stay around the charger for a long time and then adhere to the photosensitive drum. Therefore, if the state in which the photosensitive drum does not rotate continues for a long time after the formation of the visible image, a large amount of impurities adhere to a portion of the photosensitive drum near the charger.
[0007]
In recent years, a hard material such as amorphous silicon has been used for the photosensitive drum. When impurities adhere to the photosensitive drum made of a hard material, it is more difficult to remove the impurities by the cleaner than when impurities are attached to the photosensitive drum made of a soft material as in the related art.
[0008]
Therefore, if a large amount of impurities adhere to one location of the photosensitive drum made of a hard material, it becomes very difficult to remove the impurities.
[0009]
Therefore, an object of the present invention is to provide an image forming apparatus that does not cause a large amount of impurities to adhere to one portion of a photosensitive drum.
[0010]
[Means to solve the problem]
The image forming apparatus of the present invention includes a rotation control unit that rotates the photosensitive drum at a predetermined interval after image formation, regardless of image formation, in order to prevent a large amount of impurities from adhering to one location of the photosensitive drum.
[0011]
By rotating the photoconductor drum in this manner, a specific portion of the photoconductor drum is not positioned near the charger for a long time. Therefore, it is possible to prevent a large amount of impurities from adhering to a specific portion of the photosensitive drum.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is an overall view of an image forming apparatus 100 according to the present embodiment.
[0013]
When a print request is issued to the image forming apparatus 100, the control unit 201 provided in the image forming apparatus 100 shown in FIG. 2 issues a rotation instruction of the photosensitive drum 101 to the rotation control unit 202 for image formation. give. Next, the control means 201 applies a voltage to the charger 102 to uniformly charge the surface of the photosensitive drum 101.
[0014]
A laser beam is applied to the charged portion of the photosensitive drum 101 according to an instruction from the control unit 201, and a latent image is formed on the photosensitive drum 101. The control unit 201 forms a visible image on the photosensitive drum 101 by attaching toner to the latent image. The visible image formed on the photosensitive drum 101 is once transferred to the transfer drum 104. When the visible images of four colors of cyan, magenta, yellow, and black are sequentially transferred from the photosensitive drum 101 to the transfer drum 104, the visible images are transferred between the transfer drum 104 and the transfer roller 105 on the recording paper M. Is transferred to The toner and electric charges remaining on the photosensitive drum 101 are removed by the cleaner 111, and the photosensitive drum 101 returns to a state before being charged by the charger 102.
[0015]
In the present embodiment, the recording paper M is supplied from a paper supply cassette 106 provided in the image forming apparatus 100. The recording paper M is transported from the paper feed cassette 106 to between the transfer drum 104 and the transfer roller 105 by the rotation control unit 202 rotating the transport roller 107 in accordance with an instruction from the control unit 201.
[0016]
When the visible image is transferred between the transfer drum 104 and the transfer roller 105, the recording paper M is conveyed to the fixing unit 109 by the paper discharge belt 108 driven by the rotation control means 202 according to the instruction of the control means 201. You.
[0017]
The fixing device 109 includes a fixing roller 310 and a pressure roller 320. The fixing roller 310 and the pressure roller 320 are in pressure contact with each other, and are rotated by the rotation control unit 202 in accordance with an instruction from the control unit 201 to pinch and convey the recording paper M to fix the visible image transferred to the recording paper. It is possible.
[0018]
The image forming apparatus 100 switches to the standby mode when there is no print request for a predetermined time in order to avoid wasteful power consumption in the ready mode, which is an operation mode in which printing can be performed immediately when a print request is issued.
[0019]
For example, since the surface of the fixing roller 310 is always heated to a high temperature in the ready mode, if the print request is not issued for a predetermined time, the control unit 201 switches the operation mode to the preheat mode. In the preheat mode, the surface of the fixing roller 310 is ready to reduce power consumption of a heater provided in the fixing roller 310 and to enable printing as soon as a print request is issued. It is kept lower than in the mode.
[0020]
If a print request is not issued for a predetermined time after switching to the preheat mode, the control unit 201 switches the operation mode to the sleep mode.
[0021]
The sleep mode is an operation mode in which the fixing unit 109 is not heated and the power consumption of the entire image forming apparatus 100 is suppressed.
[0022]
When a print request is issued when a standby mode such as a preheat mode or a sleep mode is selected, the control unit 201 switches the operation mode to a ready mode, and the photoconductor is charged by the charger 102 for image formation. The drum 101 is charged. When the photosensitive drum 101 is charged, a high voltage is applied to the charger 102, so that impurities such as NOx are generated around the charger 102. This impurity adheres to a portion of the photosensitive drum 101 near the charger 102.
[0023]
If a print request is not issued for a predetermined time in the ready mode, the operation mode switches from the ready mode to the preheat mode. The continuation of the ready mode time longer than the predetermined time means that the photosensitive drum 101 rotates at predetermined time intervals at least for image formation based on a print request. Therefore, in the ready mode, there is a relatively small possibility that a large amount of impurities will adhere to one portion of the photosensitive drum.
[0024]
When the print request issuance interval is long and the operation mode is switched from the ready mode to the preheat mode, the photosensitive drum 101 does not rotate for a long time, so that a large amount of impurities adhere to the photosensitive drum 101 near the charger 102 in a large amount. .
[0025]
Therefore, even in the case where the print request is not issued for a long time, in order to prevent the impurities from concentrating and adhering, the rotation control unit 202 operates according to the instruction of the control unit 201 regardless of the image formation as follows. The photosensitive drum 101 is rotated.
[0026]
When switching the operation mode to the preheat mode, the control unit 201 first instructs the rotation control unit 202 to stop the rotation of the photosensitive drum 101 (S401 in FIG. 4). When the rotation control unit 202 is instructed to stop the rotation, the control unit 201 starts the first timer 221 and causes the first timer 221 to measure the stop time of the photosensitive drum 101. When the first timer 221 is started, the control means 201 sets 0 to the first flag 231 (FIG. 4, S402).
[0027]
When the stop time of the photosensitive drum 101 measured by the first timer 221 exceeds a predetermined time, the control unit 201 refers to the value of the first flag 231 (S403 in FIG. 4). When the value of the first flag 231 is 0, the control unit 201 sets 1 as the value of the first flag 231 and instructs the rotation control unit 202 to rotate the photosensitive drum 101. When the rotation is instructed, the control means 201 stops the first timer 221, resets the second timer 222, and causes the second timer 222 to measure the rotation time of the photosensitive drum 101 (FIG. 4, S404). .
[0028]
When the rotation time measured by the second timer 221 exceeds a predetermined time, the control unit 201 refers to the value of the first flag 231 (S405 in FIG. 4). If the value of the first flag 231 is 1, the control unit 201 sets 0 as the value of the first flag 231 and instructs the rotation control unit 202 to stop the rotation of the photosensitive drum 101. When instructing to stop the rotation, the control unit 201 stops the second timer 222, resets the first timer, and causes the first timer 221 to measure the stop time of the photosensitive drum 101 (FIG. 4, S406). ).
[0029]
As described above, when the rotation of the photosensitive drum 101 is stopped for a predetermined time or more, the rotation control unit 202 rotates the photosensitive drum 101 even if there is no print request. Therefore, it is possible to prevent impurities such as NOx stagnating around the charger 102 from being concentrated on the photosensitive drum 101 near the charger 102. Therefore, the impurities adhere to the entire photosensitive drum 101 little by little, so that the impurities can be easily removed.
[0030]
The reason why the photosensitive drum 101 is rotated is to prevent a large amount of impurities from adhering to a specific portion of the photosensitive drum 101. Therefore, the rotation time of the photosensitive drum 101 may be long enough that the portion of the photosensitive drum 101 where the impurities adhere can rotate to a position where the impurities do not adhere by rotation.
[0031]
Also, by rotating the photoconductor drum 101 in this way, an air current is generated around the photoconductor drum 101, and the airflow causes impurities staying around the charger 102 to escape from the periphery of the charger 102. Can be.
[0032]
The control unit 201 monitors the first timer 221, the second timer 222, and the first flag 231 until the preheat mode ends. The preheat mode is ended when a print request is issued by a user or the like or continues for several hours, for example (FIG. 4, S411). When the preheat mode is completed by continuing for several hours, the image forming apparatus operates in the sleep mode in which the power consumption of the image forming apparatus is reduced as much as possible.
[0033]
In the sleep mode, since the operation of removing impurities has already been performed at the time of preheating, it can be said that the influence of the impurities on the photosensitive drum 101 is small. However, if there is no large space around the charger 102 due to the structure, the impurities may easily accumulate. In such a case, the photosensitive drum 101 may be rotated at a predetermined interval in the sleep mode as in the preheat mode.
[0034]
Although the case where the photosensitive drum 101 is rotated in the standby mode (preheat mode and sleep mode) has been described above, the photosensitive drum 101 may be rotated in the ready mode.
[0035]
In the ready mode, the photosensitive drum does not rotate between the time when printing is completed and the time when the mode is switched to the preheat mode. Therefore, when the photosensitive drum 101 is rotated in the ready mode, it is possible to prevent impurities from adhering to the portion of the photosensitive drum 101 near the charger 102 during this time.
[0036]
In the case of a tandem-type image forming apparatus including image forming units for each of the four colors, the same rotation control may be performed on the photosensitive drums of each image forming unit. In that case, each photosensitive drum does not have to be rotated simultaneously. Further, the present invention can be applied to an image forming apparatus that performs only monochrome printing.
[0037]
【The invention's effect】
As described above, by rotating the photoconductor drum, a specific portion of the photoconductor drum does not stay near the charging device for a long time. Therefore, it is possible to prevent a large amount of impurities from adhering to a specific portion of the photosensitive drum.
[Brief description of the drawings]
FIG. 1 is an overall view of an image forming apparatus according to the present invention.
FIG. 2 is a schematic block diagram of the image forming apparatus of the present invention.
FIG. 3 is a flowchart illustrating a procedure of rotation of a fixing roller and a pressure roller.
[Explanation of symbols]
REFERENCE SIGNS LIST 100 Image forming apparatus 101 Photoconductor drum 102 Charging device 104 Transfer drum 109 Fixing device 111 Cleaner 201 Control means 202 Rotation control means 310 Fixing roller 320 Pressure roller

Claims (2)

An image forming apparatus comprising: a rotation control unit configured to rotate the photosensitive drum at predetermined intervals after image formation. The image forming apparatus according to claim 1, wherein the rotation control unit rotates the photosensitive drum in a standby mode.

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