JP6805976B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus, and more particularly to a technique for optimizing refreshing of a photoconductor drum.

In an image forming apparatus such as a laser printer or a digital compound machine, first, the surface of a photoconductive photoconductor is uniformly charged by a charging means, and then exposed by an exposure means to form an electrostatic latent image. , This electrostatic latent image is developed into a toner image by a developing means. Next, the toner image is transferred to the surface of a printed matter such as paper by a transfer means, and then fixed to the surface of the printed matter by a fixing means to complete a series of image forming steps. Further, the photoconductor after the toner image transfer is prepared for the next image formation by removing the toner remaining on the surface of the photoconductor by a cleaning means and, if necessary, exposing the photoconductor with a static elimination lamp to eliminate static electricity.

As the photoconductor used in the image forming apparatus, those having various structures made of various materials having photoconductivity have been put into practical use, and in particular, the amorphous silicon photoconductor has high strength and durability. It is known to have excellent and practical sensitivity. However, the amorphous silicon photoconductor has a problem that image flow is likely to occur.

That is, when the charging device as the charging means or the transfer means is energized and discharged, the components in the air are decomposed by the ozone generated at that time, and ion products such as NOx and SOx are generated. At the same time, the surface of the amorphous silicon photoconductor is oxidized to form an oxide film that easily adsorbs ion products and water molecules. Then, the ion product generated by the electric discharge is adsorbed on this oxide film. Then, since the ion product is water-soluble and easily takes in water in the air, and the oxide film itself easily adsorbs water, it adsorbs a large amount of water especially under high humidity conditions, and the surface resistance of the photoconductor. Is significantly reduced. In addition, paper dust generated from the paper to be printed and adhering to the surface of the photoconductor is also water-absorbent and easily adsorbs water, which causes a decrease in the surface resistance of the photoconductor. Therefore, a lateral flow (leakage) of the potential occurs at the edge portion of the electrostatic latent image formed on the surface of the photoconductor, and as a result, an image flow occurs in the formed image.

Therefore, in order to prevent the occurrence of image flow, the surface of the amorphous silicon photoconductor is periodically refreshed (polished) to remove adsorbed ion products, water, paper dust, etc. together with the oxide film on the surface. Has been proposed (for example, Patent Document 1). According to this, the cleaning means of the image forming apparatus is provided with a polishing member (polishing roller or the like) that is the same as or separate from the member (cleaning blade or the like) for removing toner. Then, at any time, for example, at the start of operation or the end of operation of the image forming apparatus, an abrasive or waste toner to which the abrasive is added is present at the contact portion of the polishing member with the photoconductor. The surface of the photoconductor is refreshed by rotating the photoconductor for a certain period of time with the abrasive member in contact with the surface of the photoconductor.

Next, in recent years, instead of the corotron or scorotron type charging means, a charging means (charging roller or the like) that charges the photoconductor by contact arrangement or proximity arrangement with a small amount of ozone generated has become mainstream. Some of these charging means charge the photoconductor by applying a vibration voltage in which a DC voltage and an AC voltage are superimposed, but the accuracy is not affected by environmental changes such as temperature and humidity and aging of the photoconductor and the charging member. Providing a charging means for an image forming apparatus capable of setting an appropriate inter-peak voltage value of a good AC voltage (for example, Patent Documents 2 and 3) has been proposed.

Japanese Unexamined Patent Publication No. 11-3014 JP-A-2007-199094 Japanese Unexamined Patent Publication No. 2012-47879

The surface condition of the photoconductor, that is, the thickness of the oxide film formed on the surface of the photoconductor, the amount of ion products and paper dust adsorbed on the surface, the degree of moisture absorption, etc., are the environmental conditions in which the image forming apparatus is used. In particular, it varies greatly depending on the humidity and the material of the paper used. Therefore, in the methods described in Patent Documents 1 to 3, in order to prevent image flow from occurring under any usage environment, the polishing time and the like are such that the surface of the photoconductor is excessively polished. It is common to set the refresh conditions for.

However, in that case, when high humidity conditions such as summer and rainy weather continue and the degree of moisture absorption is extremely high, the amount of polishing is set based on the fact that users who require high quality images can also follow. Therefore, for other users who are in a normal state where the degree of moisture absorption is not very high (rather, it is often in this state), general image quality, or the minimum necessary image quality is required. Will scrape the photoconductor too much, which may shorten the life of the photoconductor more than necessary. In addition, power consumption, refresh time, and toner are wasted.

An object of the present invention is to more accurately refresh a photoconductor in response to the surrounding environment and user requirements without shortening the life of the photoconductor more than necessary and wasting power consumption, refresh time, and toner. The purpose.

The image forming apparatus according to one aspect of the present invention has a photoconductor drum on which a toner image is formed on the surface, measures an image forming unit that forms an image on a recording medium, and measures the ambient temperature and humidity of the photoconductor drum. The temperature and humidity sensor, the timer that measures the time that the photoconductor drum is left in a predetermined ambient temperature and humidity environment, and the image forming unit are controlled to attach the surface of the photoconductor drum. The refresh to be performed on the photoconductor drum according to the control unit for performing the refresh operation for removing the kimono, the ambient temperature and humidity of the photoconductor drum, and the leaving time in the environment of the ambient temperature and humidity. A refresh table that defines a refresh amount of operation and a storage unit that stores a cumulative amount of refreshes that have been performed so far on the photoconductor drum are provided, and the control unit is obtained from the temperature / humidity sensor and the timer. The refresh amount corresponding to the temperature, humidity and leaving time, and the refresh cumulative amount are read from the storage unit, and the larger the refresh cumulative amount, the smaller the refresh amount to be performed on the photoconductor drum. The read refresh amount is adjusted, and the image forming unit is made to perform the refresh operation according to the refresh amount after the adjustment.

According to the above invention, the photoconductor can be refreshed more accurately according to the surrounding environment and user's request without shortening the life of the photoconductor more than necessary and wasting power consumption, refresh time, and toner. be able to.

It is a figure which shows the structure of the image forming apparatus which concerns on one Embodiment of this invention. It is a functional block diagram which shows the internal structure of an image forming apparatus. It is a figure which shows the correspondence relationship between the ambient temperature, humidity and the leaving time of a photoconductor drum, and a refresh mode. It is a flowchart of the refresh process of a photoconductor drum. It is a figure which shows the adjustment example of a refresh mode.

Hereinafter, the image forming apparatus according to the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front sectional view showing the structure of an image forming apparatus according to an embodiment of the present invention.

The image forming apparatus 1 according to the embodiment of the present invention is a multifunction device having a plurality of functions such as a copy function, a printer function, a scanner function, and a facsimile function. The image forming apparatus 1 includes an operation unit 47, an image forming unit 12, a fixing unit 13, a paper feeding unit 14, a document feeding unit 6, a document reading unit 5, and the like in the apparatus main body 11.

The operation unit 47 receives instructions such as an image formation operation execution instruction and a document reading operation execution instruction from the operator regarding various operations and processes that can be executed by the image forming apparatus 1. The operation unit 47 includes a display unit 473 that displays operation guidance and the like to the operator. The display unit 473 is provided with a touch panel, and the operator can operate the image forming apparatus 1 by touching the keys displayed on the screen.

When the image forming apparatus 1 performs the document reading operation, the document reading unit 5 optically reads the image of the document fed by the document feeding unit 6 or the document placed on the document mounting glass 161. Generate image data. The image data generated by the document reading unit 5 is stored in the built-in HDD, a computer connected to the network, or the like.

When the image forming apparatus 1 performs the image forming operation, it is based on the image data generated by the document reading operation, the image data received from the computer connected to the network, the image data stored in the built-in HDD, and the like. The image forming unit 12 forms a toner image on the recording paper P as a recording medium to be fed from the paper feeding unit 14. In the case of color printing, the image forming unit 12M for magenta, the image forming unit 12C for cyan, the image forming unit 12Y for yellow, and the image forming unit 12B for black of the image forming unit 12 are each the above-mentioned image. A toner image is formed on the surface of the photoconductor drum 121 by the steps of charging, exposing, and developing based on the image composed of each color component constituting the data, and the toner image is transferred to the intermediate transfer belt 125 by the primary transfer roller 126. Transfer to top.

The toner images of the above colors transferred onto the intermediate transfer belt 125 are superposed on the intermediate transfer belt 125 by adjusting the transfer timing to obtain a color toner image. The secondary transfer roller 210 transfers the toner image of the color formed on the surface of the intermediate transfer belt 125 from the paper feed unit 14 to the transfer path 190 at the nip portion N with the drive roller 125A with the intermediate transfer belt 125 sandwiched therein. It is transferred to the transported recording paper P. After that, the fixing unit 13 fixes the toner image on the recording paper P to the recording paper P by thermocompression bonding. The color image-formed recording paper P for which the fixing process has been completed is discharged to the discharge tray 151.

The paper feed unit 14 includes a manual feed tray 141 and a plurality of paper feed cassettes. When the size of the recording paper is specified by the operator, the pickup roller 145 of the paper feed cassette containing the recording paper of the size is rotationally driven, and the recording paper P stored in each paper feed cassette is inserted into the nip. Transport toward part N.

When double-sided printing is performed in the image forming apparatus 1, the recording paper P on which an image is formed on one side of the image forming unit 12 is placed in a state of being nipped in a discharge roller pair 159, and then the recording paper is set. P is switched back by the discharge roller pair 159 and sent to the reverse transfer path 195, and is again conveyed to the nip portion N and the fixing portion 13 in the upstream region in the transfer direction of the recording paper P by the transfer roller pair 19. As a result, the image forming unit 12 forms an image on the other surface of the recording paper.

In the image forming operation described above, after the toner image formed on the surface of the photoconductor drum 121 is transferred to the intermediate transfer belt 125 and before the next toner image is formed on the photoconductor drum 121, the toner image is formed on the surface of the photoconductor drum 121. The residual toner is removed by the cleaning device 127. More specifically, the cleaning device 127 has a illustrated cleaning blade having a tip edge that abuts on the outer peripheral surface of the photoconductor drum 121, and a illustrated polishing roller that abuts on the outer peripheral surface of the photoconductor drum 121. The polishing roller rotates so as to have a peripheral surface velocity different from the velocity of the outer peripheral surface of the photoconductor drum 121 or a velocity vector in the opposite direction.

The toner supplied to the photoconductor drum 121 in the developing process is rubbed against the photoconductor drum 121 by the cleaning blade. As a result, the deposits adhering to the outer peripheral surface of the photoconductor drum 121 are preferably removed. Further, the polishing roller rubs the toner on the peripheral surface of the photoconductor drum 121. As a result, the deposits adhering to the outer peripheral surface of the photoconductor drum 121 are preferably removed.

When the image forming operation is repeated for a long period of time, paper dust or the like adheres to the surface of the photoconductor drum 121, which causes deterioration of print quality such as image flow. In particular, when the photoconductor drum 121 is made of amorphous silicon, an oxide film is formed on the surface of the photoconductor drum 121, and ion products generated in the charging process are adsorbed on the oxide film. When the photoconductor drum 121 in such a state is left in a hot and humid environment for a long period of time, moisture in the air, paper dust, etc. are adsorbed on the surface of the photoconductor drum 121, and the surface resistance is significantly reduced for printing. The quality deteriorates. Therefore, each of the image forming units 12B, 12Y, 12C, and 12M operates the photoconductor drum 121 and the cleaning device 127 at the timing when the image forming is not performed, such as when the operation of the image forming apparatus 1 starts or ends. Then (and in some cases, toner is also supplied), the surface of the photoconductor drum 121 is polished to perform a refresh operation to remove deposits.

Next, the electrical configuration of the image forming apparatus 1 will be described. FIG. 2 is a functional block diagram showing an internal configuration of the image forming apparatus 1.

The image forming apparatus 1 includes a control unit 10, an operation unit 47, a document feeding unit 6, a document reading unit 5, an image forming unit 12, a fixing unit 13, a temperature / humidity sensor 60, a timer 70, a storage unit 80, an HDD 90, and the like. Be prepared.

The document reading unit 5 includes a reading mechanism 163 (FIG. 1) having a light irradiation unit, a CCD sensor, and the like under the control of the control unit 10. The document reading unit 5 irradiates the document with the light irradiation unit and receives the reflected light with the CCD sensor to read the image from the document.

As shown in FIG. 1 in addition to FIG. 2, the operation unit 47 receives instructions from the operator regarding various operations and processes that can be executed by the image forming apparatus 1. The operation unit 47 includes a (touch panel type) display unit 473 having a touch panel function.

The temperature / humidity sensor 60 measures the temperature and humidity inside the apparatus main body 11 of the image forming apparatus 1. That is, the temperature / humidity sensor 60 is a sensor that measures the ambient temperature and humidity of the photoconductor drum 121.

The timer 70 is left in an environment where the photoconductor drum 121 has a predetermined ambient temperature and humidity (for example, the ambient temperature and humidity of the photoconductor drum 121 detected by the temperature / humidity sensor 60 at the timing when refreshing should be performed). Time the time.

The storage unit 80 is composed of a non-volatile memory such as a flash memory, and can continue to hold the stored contents even when the power of the image forming apparatus 1 is turned off. More specifically, the storage unit 80 stores the refresh table 81, the cumulative refresh amount 82, the number of manual refreshes 83, and the like.

The refresh table 81 is a table in which the refresh amount (time for performing the refresh operation) to be performed on the photoconductor drum 121 is defined and stored. In the present embodiment, the refresh amount is expressed as a refresh mode (sometimes simply referred to as a mode) for convenience. For example, there are 11 modes from 0 to 10, and mode {1} means that the photoconductor drum 121 is refreshed with an operating time of 1 minute and a toner supply amount of 100 mg, and the operating time is 1 for each mode up. The amount of toner supplied increases by 100 mg. That is, the refresh amount in the mode {10} is the largest, and the photoconductor drum 121 is refreshed with an operating time of 10 minutes and a toner supply amount of 1000 mg. On the contrary, the operation time of the mode {0} is 0 minutes, and the toner supply amount is 0 mg. That is, the mode {0} indicates that refreshing is not performed.

The refresh mode is determined according to the ambient temperature and humidity of the photoconductor drum 121 and the time that the photoconductor drum 121 is left in an environment of the ambient temperature and humidity. FIG. 3 is a diagram showing the correspondence between the ambient temperature, humidity and leaving time of the photoconductor drum 121 and the refresh mode. The higher the ambient temperature, the higher the ambient humidity, and the longer the standing time of the photoconductor drum 121, the larger the refresh amount is selected. The refresh table 81 maintains a correspondence between the ambient temperature, humidity and leaving time of the photoconductor drum 121 and the refresh mode, that is, the refresh amount.

The refresh cumulative amount 82 is data representing the cumulative amount of refreshes performed so far (that is, from the time when the photoconductor drum 121 is replaced to the present time) on the photoconductor drum 121. For example, the number of refreshes is set to the cumulative refresh amount 82.

The user can input a refresh instruction of the photoconductor drum 121 to the image forming apparatus 1 through the operation unit 47 at an arbitrary timing, and when the refresh instruction is given, the image forming units 12B to 12B under the control of the control unit 101. 12M performs a refresh operation. The manual refresh count 83 is data representing the number of refresh operations performed according to the instruction of such a user. In the manual refresh, the image forming units 12B to 12M refresh the photoconductor drum 121 under the control of the control unit 101, for example, with an operating time of 2 minutes and a toner supply amount of 200 mg.

The HDD 90 is a large-capacity storage device that stores a document image or the like read by the document reading unit 5.

The control unit 10 is composed of a processor, RAM, ROM, a dedicated hardware circuit, and the like. The processor is, for example, a CPU, an MPU, an ASIC, or the like. The control unit 10 includes a control unit 101. The control unit 10 functions as a control unit 101, for example, by operating the processor according to a control program stored in the HDD 90.

The control unit 101 controls the overall operation of the image forming apparatus 1. The control unit 101 is connected to a document reading unit 5, a document feeding unit 6, an image forming unit 12, a fixing unit 13, an operation unit 47, a temperature / humidity sensor 60, a timer 70, a storage unit 80, an HDD 90, and the like. The control unit 101 controls each of the above-mentioned mechanisms to be connected, and transmits / receives a signal or data to / from each mechanism. In particular, the control unit 101 controls the image forming units 12B to 12M to perform the refresh operation of the photoconductor drum 121.

Next, the refresh process of the photoconductor drum 121 in the image forming apparatus 1 will be described. FIG. 4 is a flowchart of the refresh process of the photoconductor drum 121.

First, the control unit 101 determines the timing at which the photoconductor drum 121 should be refreshed (S1). For example, the control unit 101 does not set the time when the operation of the image forming apparatus 1 starts or ends as the timing when the photoconductor drum 121 should be refreshed, and does not set the timing when the refresh should be performed at other times.

When it is not the timing to refresh the photoconductor drum 121 (NO in S1), the control unit 101 determines whether or not there is a refresh instruction from the user (S2). If there is a refresh instruction from the user (YES in S2), the control unit 101 refreshes the photoconductor drum 121 with a predetermined refresh amount (S7). On the other hand, if there is no refresh instruction from the user (NO in S2), the process returns to step S1 and the refresh timing of the photoconductor drum 121 is determined again.

When it is time to refresh the photoconductor drum 121 (YES in S1), the control unit 101 obtains the ambient temperature and humidity of the photoconductor drum 121 from the temperature / humidity sensor 60 at this time and also from the timer 70. The time that the photoconductor drum 121 is left in the environment of the temperature and humidity is acquired (S3).

When the ambient temperature, humidity, and leaving time of the photoconductor drum 121 are acquired, the control unit 101 refers to the refresh table 81 of the storage unit 80, and sets a refresh mode (refresh amount) corresponding to the temperature, humidity, and leaving time. Acquire (S4).

Further, the control unit 101 acquires the cumulative refresh amount 82 and the manual refresh count 83 from the storage unit 80 (S5), and the refresh mode acquired from the refresh table 81 according to the refresh count and the manual refresh count so far (S5). The refresh amount) is adjusted (S6). Then, the control unit 101 refreshes the photoconductor drum 121 in the adjusted refresh mode (S7).

FIG. 5 is a diagram showing an adjustment example of the refresh mode, and shows an adjustment example of the mode {6} (refresh operation time 6 minutes, toner supply amount 600 mg). The vertical axis represents the refresh mode, that is, the refresh amount to be performed on the photoconductor drum 121, and the horizontal axis represents the number of refreshes, that is, the cumulative amount of refreshes performed on the photoconductor drum 121 so far.

When the refresh is performed for the first time (first time), the control unit 101 applies the mode {6} as it is to refresh the photoconductor drum 121. In the second refresh, the control unit 101 reduces the mode by a predetermined amount A2 (an example of a predetermined second amount). In the example of FIG. 5, the control unit 101 lowers the mode by one step, that is, shortens the operation time by 1 minute and reduces the toner supply amount by 100 mg to the mode {5} (refresh operation time 5 minutes, toner supply amount). The photoconductor drum 121 is refreshed with (500 mg). After that, similarly, the control unit 101 refreshes the photoconductor drum 121 by lowering the mode one step at a time as the number of refreshes increases by one (an example of a predetermined first amount). For example, in the fifth refresh, the control unit 101 refreshes the photoconductor drum 121 in the mode {2} (operating time 2 minutes, toner supply amount 200 mg).

Here, it is assumed that the user performs the first manual refresh after the fifth refresh is performed. In that case, in the sixth refresh, the control unit 101 increases the mode by a predetermined amount A3 (an example of a predetermined third amount). In the example of FIG. 5, the control unit 101 raises the mode by one step, that is, extends the operation time by 1 minute and increases the toner supply amount by 100 mg to the mode {3} (refresh operation time 3 minutes, toner supply amount). The photoconductor drum 121 is refreshed with 300 mg).

After the manual refresh is performed at least once, the control unit 101 gradually reduces the amount of refresh to be performed on the photoconductor drum 121 as the number of refreshes increases by one. For example, in the seventh refresh, the control unit 101 reduces the mode by a predetermined amount A4 (an example of a predetermined fourth amount). In the example of FIG. 5, the control unit 101 shortens the operation time by 10 seconds, reduces the toner supply amount by 100 mg, and refreshes the photoconductor drum 121.

Further, it is assumed that the user performs the second manual refresh after the ninth refresh is performed. In that case, in the 10th and subsequent refreshes, the control unit 101 refreshes the photoconductor drum 121 by fixing the refresh amount to a predetermined amount A5 (an example of a predetermined fifth amount).

In the example of FIG. 5, the manual refresh is performed twice, but if the manual refresh is not performed even once, the mode decreases as the number of refreshes increases, and when the mode {0} is reached, the control unit 101 changes. , The photoconductor drum 121 is no longer refreshed. As a result, frequent refreshing of the photoconductor drum 121 is suppressed, downtime can be eliminated, power consumption can be reduced, toner waste can be prevented, and the life of the photoconductor drum 121 can be extended. On the other hand, when the manual refresh is performed a plurality of times as in the example of FIG. 5, the photoconductor drum 121 is refreshed with a reduced refresh amount, and the print image quality can be improved.

As described above, according to the present embodiment, the situation and the user's request can be made more accurately without shortening the life of the photoconductor drum 121 more than necessary and causing waste of power consumption, refresh time, and toner. It is possible to refresh the photoconductor drum 121 corresponding to the above.

The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, the configurations and treatments shown in the above embodiments with reference to FIGS. 1 to 5 are merely one embodiment of the present invention, and the present invention is not intended to be limited to the configurations and treatments.

1 Image forming device 60 Temperature / humidity sensor 70 Timer 80 Storage unit 81 Refresh table 82 Refresh cumulative amount 83 Manual refresh count 101 Control unit 12B to 12M Image forming unit 121 Photoreceptor drum

Claims (3)

An image forming unit having a photoconductor drum on which a toner image is formed on the surface and forming an image on a recording medium,
A temperature / humidity sensor that measures the ambient temperature and humidity of the photoconductor drum,
A timer that measures the time that the photoconductor drum is left in a predetermined ambient temperature and humidity environment, and
A control unit that controls the image forming unit to perform a refresh operation for removing deposits on the surface of the photoconductor drum.
A refresh table that defines the refresh amount of the refresh operation to be performed on the photoconductor drum according to the ambient temperature and humidity of the photoconductor drum and the leaving time in the environment of the ambient temperature and humidity, and the photosensitivity. It is equipped with a storage unit that stores the cumulative amount of refreshes performed so far for the body drum.
The control unit
The refresh amount corresponding to the temperature, humidity and leaving time obtained from the temperature / humidity sensor and the timer, and the refresh cumulative amount are read from the storage unit, and the larger the refresh cumulative amount, the more the photoconductor drum is subjected to. The read-out refresh amount is adjusted so that the power refresh amount is reduced, and the image forming unit is made to perform the refresh operation according to the adjusted refresh amount .
Each time the cumulative refresh amount increases by a predetermined first amount, the refresh amount to be performed on the photoconductor drum is reduced by a predetermined second amount.
Further, the storage unit stores the number of manual refreshes, which is the number of times the refresh operation is performed according to the user's instruction.
The control unit is an image forming apparatus that increases the refresh amount to be performed on the photoconductor drum by a predetermined third amount each time the number of manual refreshes is increased by one . After the manual refresh is performed at least once, the control unit determines the amount of refresh to be performed on the photoconductor drum each time the number of refreshes is increased by the predetermined second. The image forming apparatus according to claim 1 , wherein a predetermined fourth amount is reduced, which is smaller than the amount of. When the number of manual refreshes exceeds a predetermined number, the control unit determines a predetermined refresh amount to be performed on the photoconductor drum regardless of the cumulative refresh amount. The image forming apparatus according to claim 2 , which is fixed to a quantity.