JP2010211068A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus, capable of shortening the time required for starting of the image forming apparatus, by making the heating time of a photoreceptor in starting of the image forming apparatus shorter. <P>SOLUTION: The image forming apparatus 100, having the photoreceptor 1; electrostatic image formation means 2, 3 for forming an electrostatic image in the photoreceptor: a developing means 4 for developing the electrostatic image formed in the photoreceptor by a developer; a heating means 11 for heating the photoreceptor; and an adjustment means 21 for adjusting time for heating the photoreceptor by the heating means, has a photoreceptor used amount detection means 23 for detecting a used amount of the photoreceptor, wherein the adjustment means adjusts the time for heating the photoreceptor by the heating means, before the image forming apparatus goes into a state where the image can be formed in power application of the image forming apparatus by the used-amount of the photoreceptor detected by the photoreceptor used-amount detection means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printer, a copying machine, and a facsimile using an electrophotographic system.

  In an electrophotographic image forming apparatus, a corona charger having a wire electrode and a shield plate as constituent members is used as a charging unit and a discharging unit of a photosensitive member (electrophotographic photosensitive member). In this corona charger, a corona current generated by applying a high voltage of about 4 to 8 kv to the wire electrode is applied to the surface of the photoconductor to charge and neutralize the surface of the photoconductor.

However, ozone (O ₃ ) is generated with corona discharge. The generated ozone oxidizes nitrogen in the air to generate nitrogen oxides (NOx) and the like. Furthermore, the generated nitrogen oxides react with moisture in the air to generate nitric acid and the like. Corona discharge products such as nitrogen oxides and nitric acid adhere to and accumulate on the photoreceptor and peripheral devices and contaminate their surfaces. In particular, when the image forming apparatus is installed in a high-humidity environment, the corona discharge product has a high hygroscopic property. Therefore, the surface of the photoreceptor on which the corona discharge product is adsorbed is absorbed by the adsorbed corona discharge product. Reduce resistance. As a result of such a reduction in resistance, the surface of the photoreceptor is substantially or partially reduced in charge retention capability, and image defects (hereinafter referred to as white spots, image blur, or image flow) It is simply called “image flow”).

  Further, the corona discharge product adhering to the inner surface of the shield plate of the corona charger is volatilized and released not only during the operation of the image forming apparatus but also during a long period of rest of the image forming apparatus such as at night. Then, it adheres to the surface of the photoconductor near the discharge opening of the corona charger and further absorbs moisture, thereby reducing the resistance of the surface of the photoconductor. Therefore, for the first image or several tens of images that are output first after the image forming apparatus is stopped for a long time, the image flow is in an area corresponding to the discharge opening of the corona charger that is stopped. It is likely to occur. In addition, this phenomenon is remarkable in the case of a corona charger using AC charging or negative charging as a charging method.

  In order to solve this image flow problem, a method of drying the surface of the photosensitive drum by a photosensitive heater (drum heater) that heats the photosensitive drum, which is a commonly used drum-type photosensitive member, from the inside is used. (Internal heating method). Further, in order to prevent the image from flowing when the image forming apparatus is started up with a short start-up time, a method of heating the photosensitive drum while the image forming apparatus is stopped has been used. However, since a large amount of energy is consumed during standby, in recent years, from the viewpoint of energy saving, it is required to turn off the photoconductor heater during standby.

  When the photoreceptor heater is not used during standby, image flow occurs when the image forming apparatus is started up. Therefore, it is necessary to form an image after recovering the image flow by heating the photosensitive drum.

  When such a method is used, not only the time required for starting up the fixing device but also the time for restoring the image flow greatly affects the start-up time and power consumption of the image forming device.

  In the internal heating method, it takes time until the surface temperature of the photosensitive drum rises, and power is consumed. Patent Document 1 discloses a technique for controlling a drum heater by detecting an installation environment using a temperature and humidity sensor. This is a technique in which the drum heater is activated based on the moisture amount information obtained from the temperature and humidity sensor at the time of start-up, and the photosensitive drum is heated for a period of time until the image flow is restored under the worst condition.

JP 2002-040876 A

  As described above, there is a technique for controlling the drum heater according to the temperature and humidity. However, the level of occurrence of image flow varies greatly depending on the deterioration or contamination state of the photosensitive drum or corona charger, and the stop time of the image forming apparatus main body. To do. For this reason, if only the control according to the temperature and humidity is performed, even if the degree of image flow is slight, extra power is consumed and the start-up time may be long.

  For example, even when the amount of moisture is large, when the number of formed images is small, the photoconductive drum is not deteriorated, so that image flow does not occur or is often slight. However, since the drum heater is heated based on the judgment based on the temperature and humidity, the heating may be continued after the recovery of the image flow.

  Accordingly, an object of the present invention is to provide an image forming apparatus capable of shortening the time required for starting up the image forming apparatus by shortening the heating time of the photosensitive member when starting up the image forming apparatus. That is.

  The above object is achieved by the image forming apparatus according to the present invention. In summary, the present invention provides a photosensitive member, an electrostatic image forming unit that forms an electrostatic image on the photosensitive member, a developing unit that develops the electrostatic image formed on the photosensitive member with a developer, An image forming apparatus comprising: a heating unit that heats a photoconductor; and an adjustment unit that adjusts a time for heating the photoconductor by the heating unit. The image forming apparatus includes a photoconductor usage amount detection unit that detects a usage amount of the photoconductor. The adjusting means determines the time for heating the photosensitive member by the heating unit before the image forming apparatus is ready to form an image when the image forming apparatus is turned on. According to another aspect of the invention, there is provided an image forming apparatus that adjusts according to the detected amount of use of the photoconductor.

  According to the present invention, it is possible to shorten the time required to start up the image forming apparatus by shortening the heating time of the photosensitive member when the image forming apparatus is started up.

1 is a schematic cross-sectional view of an embodiment of an image forming apparatus according to the present invention. It is a graph which shows an example of the change of the surface temperature of the photoreceptor drum by the heating of a photoreceptor heater. It is a graph for explaining the difference in ease of recovery of image flow due to the heating of the photoreceptor heater due to the difference in the usage amount of the photoreceptor drum. It is a graph which shows an example of the relationship between the number of image formations and the heating time required to restore the image flow. FIG. 3 is a schematic control block diagram of temperature adjustment control of a photosensitive drum in an embodiment of the present invention. FIG. 3 is a flowchart showing a control flow when starting up the image forming apparatus according to an embodiment of the present invention. It is a graph which shows an example of the relationship between absolute moisture content and the heating time required in order to recover an image flow. It is a general | schematic control block diagram of the temperature adjustment control of the photosensitive drum in the other Example of this invention. FIG. 10 is a flowchart illustrating a control flow when starting up an image forming apparatus according to another embodiment of the present invention. It is a graph which shows an example of the relationship between a main body stop time and the heating time required in order to recover an image flow. It is a general | schematic control block diagram of the temperature adjustment control of the photoreceptor drum in the further another Example of this invention. FIG. 10 is a flowchart illustrating a control flow when starting up an image forming apparatus according to still another embodiment of the present invention.

  The image forming apparatus according to the present invention will be described below in more detail with reference to the drawings.

Example 1
1. Image Forming Apparatus FIG. 1 is a longitudinal sectional view schematically showing a schematic configuration of a main part in an embodiment of an image forming apparatus according to the present invention. The image forming apparatus 100 according to the present exemplary embodiment is an electrophotographic printer.

  The image forming apparatus 100 includes a drum-type photoreceptor (electrophotographic photoreceptor), that is, the photoreceptor drum 1 as an image carrier. The photosensitive drum 1 is rotatably supported by the main body of the image forming apparatus 100. The photosensitive drum 1 is driven to rotate in the direction indicated by the arrow R1 (clockwise).

  Around the photosensitive drum 1, the following units are arranged almost in order along the rotation direction. First, a primary charger (corona charger) 2 as primary charging means. Next, an image exposure apparatus 3 as an image exposure unit. Next, there is a developing device 4 as a developing unit. Next, a transfer charger 5 as a transfer unit. Next, the separation charger 6 is used. Next, the separation claw 7. Next, a cleaning device 8 as a cleaning means. Next, there is a pre-exposure device 9 as a charge eliminating unit. Further, a fixing device 10 including a fixing roller and a pressure roller is provided as a fixing unit in a portion through which the transfer material P after transfer passes.

  In the image forming apparatus 100, at the time of image formation, the photosensitive drum 1 is rotationally driven at a predetermined peripheral speed (process speed) in a direction indicated by an arrow R1 (clockwise) by a motor (not shown) as a driving unit. .

  The surface of the photosensitive drum 1 is uniformly charged to a predetermined potential (400 V in this embodiment) by the primary charger 2. The surface of the charged photosensitive drum 1 is irradiated with light based on image information by the image exposure device 3. As a result, the charge at the irradiated portion is removed, and an electrostatic latent image (electrostatic image) is formed on the surface of the photosensitive drum 1. The electrostatic latent image is developed as a toner image (developer image) by a toner as a developer adhered by the developing device 4. As the developer, for example, a non-magnetic one-component developer can be used.

  The toner image formed on the photosensitive drum 1 reaches the transfer portion T between the photosensitive drum 1 and the transfer charger 5 by the rotation of the photosensitive drum 1 in the direction of the arrow R1 shown in the drawing. The transfer material P is supplied to the transfer portion T so as to match the timing of the toner image. The transfer charger 5 to which a transfer bias having a polarity opposite to the normal charging polarity of the toner is applied, and the electrostatic force generated between the photosensitive drum 1 and the transfer charger 5 is used on the photosensitive drum 1. The toner image is transferred to the transfer material P.

  The transfer material P after the transfer of the toner image is separated from the photosensitive drum 1 by the separation charger 6 to which a predetermined separation bias is applied, and is conveyed to the fixing device 10. The transfer material P conveyed to the fixing device 10 is heated and pressurized when passing between the fixing roller and the pressure roller, and the toner image is fixed on the surface thereof. Thereafter, the transfer material P is discharged to the outside of the image forming apparatus 100.

  On the other hand, the transfer residual toner remaining on the surface of the photosensitive drum 1 without being transferred to the transfer material P when the toner image is transferred is removed by the cleaning device 8. Further, the charge remaining on the surface of the photosensitive drum 1 is removed by the pre-exposure device 9. Thereafter, the photosensitive drum 1 is subjected to the next image formation.

  In the present embodiment, a sheet-like photoreceptor heater (drum heater) 11 that is a photoreceptor heating device is provided inside the photoreceptor drum 1 as a heating means. The photoconductor heater 11 is arranged for approximately one turn along the inner periphery of the photoconductor drum 1.

  In this embodiment, the photoconductor heater 11 uses a heating method using a heating wire. However, the present invention is not limited to this, and the heat generation method may use an induction heating (IH) method or a PTC heater.

  In the present embodiment, the primary charger 2 and the image exposure device 3 constitute an electrostatic image forming unit that forms an electrostatic image on the photosensitive drum 1.

2. Temperature adjustment control of the photosensitive drum 1 by the photosensitive heater 11 is performed by the temperature control device 12 as the temperature control means in accordance with an instruction from the CPU 21 (FIG. 5) as the adjustment means described later. To do so. The temperature of the photoconductor drum 1 heated by the photoconductor heater 11 is detected by a thermistor (not shown) as photoconductor temperature detection means provided inside the photoconductor drum 1. Based on the temperature information, the power supply from the power source (not shown) to the photoconductor heater 11 is controlled to control the temperature of the photoconductor drum 1 by the photoconductor heater 11.

  Here, as described above, there is a conventional technique for controlling the drum heater according to the temperature and humidity. However, it is unnecessary to control the drum heater according to the temperature and humidity even when the degree of image flow is slight. Power consumption and start-up time may be long.

  For example, even when the amount of moisture is large, when the number of formed images is small, the photoconductive drum is not deteriorated, so that image flow does not occur or is often slight. However, since the drum heater is heated based on the judgment based on the temperature and humidity, the heating may be continued after the recovery of the image flow.

  One of the objects of the present embodiment is to shorten the time required to start up the image forming apparatus 100 by shortening the heating time of the photosensitive drum 1 when the image forming apparatus 100 is started up. . One of the more detailed purposes of this embodiment is to recover an image flow that changes in accordance with the surface deterioration of the photosensitive drum 1 with a shorter start-up time.

  The image forming apparatus 100 according to the present exemplary embodiment simultaneously heats the photoconductor heater 11 and restores the fixing device 10 to restore the image flow after the power is turned on when the image forming apparatus 100 is started up. When both preparations are completed, a standby state in which image formation is possible is entered.

  The image forming apparatus 100 heats the photoconductor drum 1 to a predetermined temperature by the photoconductor heater 11, sufficiently evaporates the moisture adsorbed on the surface of the photoconductor drum 1 to restore the image flow, and then enters the standby state. Become. This prevents image flow (white spots, image blur, image flow, etc.) from occurring.

  The surface of the photosensitive drum 1 is deteriorated by image formation, and the degree of image flow is deteriorated. For this reason, in this embodiment, the heating time of the photosensitive drum 1 when the image forming apparatus 100 is started up is increased depending on the number of formed images. This will be described in more detail below.

  FIG. 2 shows a change in the surface temperature of the photoconductive drum 1 when heated by the 200 W photoconductive heater 11 used in this embodiment.

  In this embodiment, the temperature (surface temperature) of the photoconductive drum 1 is a temperature sufficient to recover the image flow by the temperature control device 12 installed in the photoconductive heater 11, and toner fusion or the like occurs. At a constant temperature of 42 ° C. The surface temperature of the photoconductive drum 1 can reach a predetermined temperature (42 ° C. in this embodiment) in about 2 minutes when power is supplied to the photoconductive heater 11.

  FIG. 3 shows the heating time of the photosensitive drum 1 under a predetermined temperature and humidity condition (in this embodiment, an environment with an absolute water content of 15 g) and an image ratio (%) which is an index indicating the degree of recovery of image flow. The relationship is shown for the initial use and after endurance of the photosensitive drum 1.

  Here, the degree of image flow is represented by an image ratio (%) which is the ratio of the printed portion of the output image. When a blank image is generated, the image ratio is low. Therefore, this image ratio (%) is an index of image flow.

  From FIG. 3, it can be seen that the photosensitive drum 1 whose durability has deteriorated takes time to evaporate moisture, and the time until the image flow is restored becomes longer. In such a photosensitive drum 1, ozone products and the like due to discharge accumulate on the surface of the photosensitive drum 1, and the amount of moisture adsorbed also increases, so the time until the moisture evaporates increases. Yes.

  Therefore, in this embodiment, when the image forming apparatus 100 is turned on, the photosensitive drum 1 is heated by the photosensitive heater 11. At this time, after the heating time determined by the number of image forming sheets counted as the usage amount of the photosensitive drum 1 has elapsed, the image forming apparatus 100 shifts to a state where image formation is possible.

  FIG. 4 shows the number of images formed (that is, the degree of deterioration of the surface of the photosensitive drum 1) in an environment with a predetermined absolute moisture content (absolute moisture content of 15 g in this embodiment) and a photoreceptor heater necessary for restoring the image flow. 11 shows the relationship with the heating time. Table 1 shows the heating time of the photoconductor heater 11 according to the number of images formed when the image forming apparatus 100 is started up in an environment with a predetermined absolute moisture content (absolute moisture content of 15 g in this embodiment).

  Note that the relationship of the heating time of the photoconductor heater 11 with respect to the number of image formations as shown in Table 1 may be used by linear interpolation.

  FIG. 5 shows a schematic control block relating to temperature adjustment control of the photosensitive drum 1 in this embodiment. In this embodiment, the CPU 21, which is an arithmetic processing unit of a control unit that performs overall control of the operation of the image forming apparatus 100 provided in the main body of the image forming apparatus 100, controls the temperature control device 12 to control the temperature adjustment of the photosensitive drum 1. Give instructions. The CPU 21 functions as an adjusting unit that adjusts the heating time of the photosensitive drum 1 by the photosensitive heater 11 that is executed under the control of the temperature control device 12. The CPU 21 gives an instruction to the temperature control device 12 according to the program and data stored in the storage device 22. Further, the image forming apparatus 100 according to the present exemplary embodiment is provided with a counter 23 that counts the number of formed images as a photoreceptor usage detection unit. The counter 23 counts and records the usage amount of the photosensitive drum 1 mounted on the image forming apparatus 100 from the initial use as the number of images formed and output using the photosensitive drum 1. In this embodiment, as shown in Table 1, the heating time of the photoconductor heater 11 when the image forming apparatus 100 is started up in accordance with the number of image forming sheets is preset and stored in the storage device 22. . Then, when the image forming apparatus 100 is started up, the CPU 21 selects the heating time of the photoconductor heater 11 from the information stored in the storage device 22 according to the information related to the number of formed images input from the counter 23. Then, the temperature control device 12 is given an instruction relating to the heating time.

  Next, with reference to FIG. 6, a control flow when starting up the image forming apparatus 100 in this embodiment will be described.

  When the power of the image forming apparatus 100 is turned on (S101), the CPU 21 supplies power to heat the fixing device 10 to a predetermined temperature, and heats the photoreceptor heater 11 to restore the image flow. Start (S102).

  The CPU 21 calculates the heating time of the photoconductor heater 11 according to the number of formed images from the information from the counter 23 and the information stored in the storage device 22 (S103).

  Then, the CPU 21 stops heating the photoconductor heater 11 after the calculated heating time has elapsed from the start of heating the photoconductor heater 11 (S104). As a result, the photosensitive drum 1 is ready for image formation.

  At this time, if the fixing device 10 is ready for image formation (S105), the main body of the image forming device 100 enters a standby state in which image formation can be started (S107). On the other hand, if the fixing device 10 is starting up (S105), the process waits until the fixing device 10 is ready to form an image (S106) and enters a standby state (S107).

  As described above, according to the present embodiment, the image flow that changes in accordance with the surface deterioration of the photosensitive drum 1 can be recovered in a shorter start-up time. That is, according to this embodiment, the heating time of the photosensitive drum 1 can be determined according to the degree of image flow, and the start-up time of the image forming apparatus 100 can be shortened. Therefore, according to this embodiment, even when the photosensitive drum 1 is heated by the photosensitive drum heater 11 when the image forming apparatus 100 is started up, the image flow can be recovered with less start-up time without using excessive power. Can be made.

Example 2
Next, another embodiment of the present invention will be described. The basic configuration and operation of the image forming apparatus of this embodiment are the same as those of the first embodiment. Accordingly, elements having the same functions and configurations as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The image forming apparatus 100 according to the present exemplary embodiment simultaneously heats the photoconductor heater 11 and restores the fixing device 10 to restore the image flow after the power is turned on when the image forming apparatus 100 is started up. When both preparations are completed, a standby state in which image formation is possible is entered.

  Also in the present embodiment, as in the first embodiment, the image forming apparatus 100 is heated to a predetermined temperature by the 200 W photoconductor heater 11, and the photoconductor drum is installed by the temperature control device 12 installed in the photoconductor heater 11. The surface temperature of 1 is kept at 42 ° C. Then, after the water adsorbed on the surface of the photosensitive drum 1 is sufficiently evaporated to restore the image flow, the standby state is set. This prevents image flow (white spots, image blur, image flow, etc.) from occurring.

  The surface of the photosensitive drum 1 is deteriorated by image formation, and the degree of image flow is deteriorated. Therefore, the heating time of the photosensitive drum 1 when the image forming apparatus 100 is started up is increased depending on the number of image formations.

  Similar to the first embodiment, it is necessary to restore the image flow and the number of images formed (that is, the degree of deterioration of the surface of the photosensitive drum 1) in an environment having a predetermined absolute moisture content (in this embodiment, an absolute moisture content of 15 g). The relationship with the heating time of the photoconductor heater 11 is as shown in FIG. Accordingly, in the present embodiment, first, as in the first embodiment, the image forming apparatus 100 in an environment having a predetermined absolute water content (in this embodiment, 15 g absolute water content) is obtained from the information shown in Table 1 above. The heating time of the photoconductor heater 11 corresponding to the number of images formed at the start-up time is obtained. Note that the relationship of the heating time of the photoconductor heater 11 with respect to the number of image formations as shown in Table 1 may be used by linear interpolation.

  Furthermore, the degree of image flow is worsened by the absolute water content calculated from the environmental temperature and humidity. Therefore, in this embodiment, the heating time of the photosensitive drum 1 when the image forming apparatus 100 is started up is also controlled based on the absolute water amount detected when the image forming apparatus 100 is started. This will be described in more detail below.

  FIG. 7 shows the relationship between the absolute water content of the environment where the image forming apparatus 100 is placed and the heating time of the photosensitive member heater 11 necessary for restoring the image flow.

  The image flow is generated by absorbing moisture in the air by contaminants on the surface of the photosensitive drum 1. The higher the amount of water in the air, the worse the degree and the longer it takes to restore the image stream. Therefore, in a low-humidity environment where no image flow occurs, the consumption of excess energy can be further reduced by not operating the photoconductor heater 11.

  Therefore, in this embodiment, when the image forming apparatus 100 is turned on, the heating time of the photoconductor heater 11 corresponding to the number of images formed in the environment of the predetermined absolute moisture amount obtained as described above is used. Is corrected by the absolute water content which is temperature / humidity information detected using the temperature / humidity detecting means. Table 2 shows the ratio of the heating time according to the absolute water content. In this example, the final heating time is calculated by multiplying the heating time obtained according to Table 1 by a correction coefficient (ratio of heating time) according to the absolute water content as shown in Table 2.

The calculation method of the heating time is as the following formula 1.
(Time determined by the number of durable sheets) x (Ratio determined by the amount of absolute moisture) = Heating time Formula 1
The heating time ratio as shown in Table 2 may be a linearly complemented value.

  FIG. 8 shows a schematic control block relating to temperature adjustment control of the photosensitive drum 1 in this embodiment. The general control block in this embodiment is basically the same as that in the first embodiment. However, in this embodiment, the image forming apparatus 100 is further provided with a temperature / humidity sensor 24 as temperature / humidity detection means for detecting the temperature and humidity of the environment in the main body. The temperature / humidity sensor 24 detects the temperature and humidity of the environment of the image forming apparatus 100 and inputs information related to the detection result to the CPU 21. In this embodiment, the storage device 22 further stores a correction coefficient (ratio of heating time) according to the absolute moisture content of the environment as shown in Table 2 in advance. When the image forming apparatus 100 is started up, the CPU 21 calculates the absolute moisture content of the environment from the information related to the environmental temperature and humidity detection results input from the temperature / humidity sensor 24, and uses the information stored in the storage device 22. Select a correction factor (ratio of heating time). Then, the CPU 21 corrects the heating time of the photoconductor heater 11 at a predetermined absolute water content obtained in the same manner as in the first embodiment by multiplying the correction coefficient (ratio of heating time) selected as described above. . The CPU 21 gives an instruction relating to the corrected heating time to the temperature control device 12.

  Next, with reference to FIG. 9, a control flow when starting up the image forming apparatus 100 in the present embodiment will be described.

  When the power of the image forming apparatus 100 is turned on (S201), the CPU 21 supplies power to heat the fixing device 10 to a predetermined temperature, and heats the photoreceptor heater 11 to restore the image flow. Start (S202).

  The CPU 21 calculates the heating time of the photoconductor heater 11 according to the number of images formed and the absolute water content from the information from the counter 23, the information from the temperature / humidity sensor 24, and the information stored in the storage device 22. (S203). Here, the CPU 21 uses the number of images formed and the absolute moisture amount calculated from the temperature and humidity information detected by the temperature / humidity sensor 24 to perform the heating time according to the above-described heating time calculation method (Equation 1). Is calculated.

  Then, the CPU 21 stops heating the photoconductor heater 11 after the calculated heating time has elapsed from the start of heating the photoconductor heater 11 (S204). As a result, the photosensitive drum 1 is ready for image formation.

  At this time, if the fixing device 10 is ready for image formation (S205), the main body of the image forming device 100 enters a standby state in which image formation can be started (S207). On the other hand, if the fixing device 10 is starting up (S205), the process waits until the fixing device 10 is ready for image formation (S206), and enters a standby state (S207).

  In the present embodiment, the heating time is determined according to the result of detecting the absolute water content in the environment when the image forming apparatus 100 is powered on. However, the present invention is not limited to this, and the heating time can also be determined based on the absolute moisture content of the environment where the image is formed and the number of images formed based on the moisture content. A more specific example will be described as follows.

  In a high-humidity environment, even when one image is formed, the heating time corresponding to the degree of deterioration of the photosensitive drum 1 can be set by increasing the number of images formed. Table 3 shows the amount of water when an image forming job is input and the number of counts advanced per sheet.

  Counting the number of counts according to Table 3, multiplying the heating time determined from the number of counts using Table 1 by a correction coefficient (ratio of heating time) according to the absolute water content as shown in Table 2, Calculate the final heating time.

The calculation method of the heating time is as the following formula 2.
(Time determined by the number of durable sheets accumulated according to the amount of moisture) × (Ratio determined by the amount of absolute moisture) = Heating time ・ ・ ・ Equation 2
The heating time ratio as shown in Table 2 may be a linearly complemented value.

  As described above, according to the present embodiment, it is possible to recover the image degradation that changes in accordance with the surface deterioration of the photosensitive drum 1 and the absolute moisture content of the environment in a shorter start-up time. That is, according to this embodiment, the heating time of the photosensitive drum 1 can be determined according to the degree of image flow, and the start-up time of the image forming apparatus 100 can be shortened. Therefore, according to this embodiment, even when the photosensitive drum 1 is heated by the photosensitive drum heater 11 when the image forming apparatus 100 is started up, the image flow can be recovered with less start-up time without using excessive power. Can be made.

Example 3
Next, another embodiment of the present invention will be described. The basic configuration and operation of the image forming apparatus of this embodiment are the same as those of the first and second embodiments. Accordingly, elements having the same functions or configurations as those of the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  The image forming apparatus 100 according to the present exemplary embodiment simultaneously heats the photoconductor heater 11 and restores the fixing device 10 to restore the image flow after the power is turned on when the image forming apparatus 100 is started up. When both preparations are completed, a standby state in which image formation is possible is entered.

  Also in the present embodiment, as in the first and second embodiments, the image forming apparatus 100 is heated to a predetermined temperature by the 200 W photoconductor heater 11 and photosensitized by the temperature control device 12 installed in the photoconductor heater 11. The surface temperature of the body drum 1 is kept at 42 ° C. Then, after the water adsorbed on the surface of the photosensitive drum 1 is sufficiently evaporated to restore the image flow, the standby state is set. This prevents image flow (white spots, image blur, image flow, etc.) from occurring.

  Here, the temperature adjustment control of the photosensitive drum 1 in this embodiment is basically the same as that in the second embodiment, and the heating time of the photosensitive heater 11 is controlled by the number of images formed and the absolute water content.

  Furthermore, when the main body of the image forming apparatus 100 is stopped and the temperature of the photoconductive drum 1 is lowered, the surface of the photoconductive drum 1 starts to absorb moisture, and the degree of image flow deteriorates with time.

  FIG. 10 shows the relationship between the main body stop time of the image forming apparatus 100 and the heating time of the photoconductor heater 11 necessary for restoring the image flow.

  Therefore, in this embodiment, the heating time of the photosensitive drum 1 when the image forming apparatus 100 is started up is also controlled by the stop time from when the image forming apparatus 100 was previously stopped to when the power is turned on this time. To do. This will be described in more detail below.

  In this embodiment, similarly to the second embodiment, the heating time of the photoconductor heater 11 obtained from the number of images formed and the absolute water content is further corrected by the main body stop time. Table 4 shows the ratio of the heating time according to the absolute water content. In this example, the heating time obtained according to Table 1 is multiplied by a correction coefficient (ratio of heating time) according to the absolute water content as shown in Table 2, and further according to the main body stop time as shown in Table 4. The final heating time is calculated by multiplying the correction coefficient (ratio of heating time).

The calculation method of the heating time is as the following formula 3.
(Time determined by the number of durable sheets) × (Ratio determined by the absolute water content) × (Ratio determined by the time when the main body was stopped) = Heating time (Formula 3)
The heating time ratio as shown in Table 4 may be a linearly complemented value.

  FIG. 11 shows a schematic control block relating to temperature adjustment control of the photosensitive drum 1 in this embodiment. The general control block in this embodiment is basically the same as that in the second embodiment. However, in this embodiment, the image forming apparatus 100 further serves as a stop time measuring unit that measures the stop time of the main body of the image forming apparatus 100 (the time when the image forming apparatus 100 is left in a power-off state). A timer 25 is provided. The timer 25 measures the time from when the image forming apparatus 100 was previously stopped to when the power is turned on, and inputs information related to the measurement result to the CPU 21. In this embodiment, the storage device 22 further stores a correction coefficient (ratio of heating time) according to the main body stop time as shown in Table 4 in advance. The CPU 21 selects a correction coefficient (ratio of heating time) from the information stored in the storage device 22 according to the information related to the stop time input from the timer 25 when the image forming apparatus 100 is started up. Then, the CPU 21 corrects the heating time obtained in the same manner as in Example 2 by multiplying the correction coefficient (ratio of heating time) selected as described above. The CPU 21 gives an instruction relating to the corrected heating time to the temperature control device 12.

  Next, with reference to FIG. 12, a control flow when starting up the image forming apparatus 100 in the present embodiment will be described.

  When the power of the image forming apparatus 100 is turned on (S301), the CPU 21 supplies power to heat the fixing device 10 to a predetermined temperature, and heats the photoreceptor heater 11 to recover the image flow. Start (S302).

  Based on the information from the counter 23, the information from the temperature / humidity sensor 24, the information from the timer 25, and the information stored in the storage device 22, the CPU 21 responds to the number of formed images, the absolute water content, and the main body stop time. The heating time of the photoconductor heater 11 is calculated (S303). Here, the CPU 21 uses the number of images formed, the absolute water amount calculated from the information related to the temperature and humidity detected by the temperature / humidity sensor 24, and the main body stop time measured by the timer 25, as described above. The heating time is calculated according to the heating time calculation method (formula 3).

  Then, the CPU 21 stops the heating of the photoconductor heater 11 after the calculated heating time has elapsed from the start of the heating of the photoconductor heater 11 (S304). As a result, the photosensitive drum 1 is ready for image formation.

  At this time, if the fixing device 10 is ready for image formation (S305), the main body of the image forming device 100 enters a standby state in which image formation can be started (S307). On the other hand, if the fixing device 10 is starting up (S305), the process waits until the fixing device 10 is ready for image formation (S306) and enters a standby state (S307).

  As described above, according to this embodiment, it is possible to recover the image flow that changes in accordance with the surface deterioration of the photosensitive drum 1, the absolute moisture content of the environment, and the main body stop time in a shorter start-up time. That is, according to this embodiment, the heating time of the photosensitive drum 1 can be determined according to the degree of image flow, and the start-up time of the image forming apparatus 100 can be shortened. Therefore, according to this embodiment, even when the photosensitive drum 1 is heated by the photosensitive drum heater 11 when the image forming apparatus 100 is started up, the image flow can be recovered with less start-up time without using excessive power. Can be made.

  In this embodiment, the control for determining the heating time in accordance with the main body stop time is combined with the temperature adjustment control of the photosensitive drum 1 described in the second embodiment, but the photosensitive member described in the first embodiment is used. It can be combined with the temperature control of the drum 1.

DESCRIPTION OF SYMBOLS 1 Photoconductor drum 2 Corona charger 3 Image exposure apparatus 4 Developing apparatus 5 Transfer charger 8 Cleaning apparatus 10 Fixing apparatus 11 Photoconductor heater 12 Temperature control apparatus 21 CPU

Claims (4)

A photosensitive member; an electrostatic image forming unit that forms an electrostatic image on the photosensitive member; a developing unit that develops the electrostatic image formed on the photosensitive member with a developer; and a heating unit that heats the photosensitive member. And an adjusting unit that adjusts a time for heating the photosensitive member by the heating unit.
Photosensitive material usage amount detecting means for detecting the usage amount of the photosensitive material is provided, and the adjusting means is controlled by the heating means before the image forming apparatus is ready to form an image when the image forming apparatus is turned on. An image forming apparatus, wherein a time for heating the photoconductor is adjusted in accordance with a usage amount of the photoconductor detected by the photoconductor usage amount detecting unit.   Temperature and humidity detecting means for detecting environmental temperature and humidity information; and the adjusting means is further adapted to the temperature and humidity information of the environment when the image forming apparatus is turned on detected by the temperature and humidity detecting means. 2. The image forming apparatus according to claim 1, wherein a time for heating the photosensitive member by the heating unit is adjusted before the image forming apparatus is ready to form an image when the image forming apparatus is turned on.   The image forming apparatus further includes stop time measuring means for measuring information relating to a stop time from when the image forming apparatus was previously stopped to when power is turned on, and the adjusting means is further measured by the stop time measuring means. The time for heating the photosensitive member by the heating means is adjusted before the image forming apparatus is ready to form an image when the image forming apparatus is turned on, according to the stop time. Item 3. The image forming apparatus according to Item 1 or 2.   Temperature / humidity detection means for detecting temperature / humidity information of the environment, and the adjusting means further includes the temperature / humidity information of the environment at the time of image formation, and the number of images formed under the temperature / humidity condition, 4. The time for heating the photosensitive member by the heating unit before the image forming apparatus becomes ready for image formation when the image forming apparatus is turned on is adjusted. Image forming apparatus.

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