JP2005331847A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus, in which dew condensation can be prevented and with which a image quality can be obtained stably. <P>SOLUTION: In an image forming apparatus, provided with an exposure device forming an electrostatic latent image on a photoreceptor and a development device supplying developer to the photoreceptor retaining the electrostatic latent image and forming a developed image on the photoreceptor, a control means is provided to drive at least one of the exposure device or the development device, regardless of the image forming action in a low-temperature environment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus typified by a laser printer and a copying machine, and more particularly to an image forming apparatus that is advantageous for preventing condensation.

  If the installation environment of the image forming apparatus changes from a low temperature environment to a normal temperature or a high temperature environment, condensation may occur inside the image forming apparatus, causing image defects or printing stoppage. In many cases, the image forming apparatus is left until condensation is eliminated, and printing is started in a state where condensation is eliminated.

  If the temperature inside the image forming device is lower than the outside air and the humidity of the outside air is high, the inside of the image forming device will be condensed, and once condensation occurs, it must be left for a long time for the dew to evaporate. End up.

  The present invention includes an exposure device that forms an electrostatic latent image on a photosensitive member, and a developing device that supplies a developer to the photosensitive member holding the electrostatic latent image and forms a developed image on the photosensitive member. The image forming apparatus further includes a control unit that drives at least one of the exposure device and the developing device regardless of the image forming operation in a low temperature environment.

  According to the present invention, it is possible to provide an image forming apparatus that can prevent condensation and can stably obtain image quality.

  An image forming apparatus to which the present invention is applied includes a photoreceptor 1, a charger 2, an exposure device 13, a developing device 10, a transfer device 4, and a fixing device 11, and an outside air temperature sensor 15. have.

  The surface of the photosensitive member 1 is charged by the charger 2, and an electrostatic latent image is formed on the photosensitive member 1 from the laser 13 serving as the light source of the exposure apparatus through the scanner motor 14, and the photosensitive member 1 holding the electrostatic latent image is developed. A developer (toner) is supplied by the apparatus 10 to form a developed image (toner image) on the photoreceptor 1.

  The toner image is transferred to a recording medium such as paper or film using a transfer belt 4 serving as a transfer device by using transfer belt supports 3 and 5 and a transfer roller 6, and the recording medium 7 holding the toner image is a fixing device. 11 is heated and fixed.

  The recording medium is fed by a pick roller 9 and the surface of the transfer belt 4 is cleaned by a cleaner 12. The respective driving sources are driven by a photosensitive member driving source 1d, a charging device driving source 2d, a developing device driving source 10d, a paper feeding driving source 9d, a cleaner driving source 12d, and a fixing device driving source 11d. These may be individually driven by a motor, but driving with a small number of motors using gears, clutches, and solenoids can provide parts at lower cost.

  A drive source may also be used for the transfer belt and the like. However, in a four-rotation type color printer, there is a configuration in which the transfer device can be operated in a driven configuration by widening the nip of the first transfer unit.

  When the outside air is at a low temperature, the entire image forming apparatus is cooled, and each component inside the image forming apparatus is at a low temperature. If air with high humidity enters the inside of the image forming apparatus in this state, each component is likely to condense. In particular, warm and humid air has a high absolute humidity and is susceptible to condensation. In the present invention, condensation is prevented by warming the inside of the image forming apparatus and reducing the temperature difference from the outside air.

  A first embodiment of the present invention is shown below. A description will be given using a laser printer as the image forming apparatus. The control unit 17 determines the operating conditions of the outside air temperature detected by the outside air temperature sensor 15 and operates the exposure device 13 as a result, thereby increasing the temperature around the exposure device and preventing condensation.

  In the laser printer, the exposure apparatus has a laser 13 and a scanner motor 14, and in particular uses the rotating operation of the scanner motor 14. As shown in FIG. 2, when the scanner motor 14 is rotated, the scanner motor generally generates heat in about 5 minutes, and the temperature rises by 10 ° C. or more. The operation of the scanner motor is continued for 5 minutes or more and 60 minutes or less, and preferably 30 minutes. The scanner motor and its driver may exceed 60 ° C. in an operation of 30 minutes or more, and the ambient temperature is raised, but generally the ambient temperature needs to be 60 ° C. or less. At a temperature of 60 ° C. or higher, the toner often exceeds the glass transition temperature and must be lower than this. Therefore, it is necessary to stop after performing the operation.

  If the outside air temperature continues to rise, the scanner motor is driven again. As described above, in order not to exceed 60 ° C., driving is performed after a predetermined stop time. Generally, the temperature inside the laser printer is lowered again after 30 minutes of stoppage, so that it is driven again after 30 minutes. The stop time and redrive time may be changed according to changes in the printer operating state and outside air temperature.

  The operating conditions for the above condensation prevention operation are shown below. Condensation occurs when the temperature difference is 4 ° C. or more with the components at a low temperature relative to the outside air. The higher the outside air humidity, the easier the condensation, and the higher the outside air temperature, the greater the amount of absolute moisture in the air.

  Accordingly, a rise in the outside air temperature around the printer during a predetermined time is detected, and this is used to drive each element to prevent condensation. Specifically, about 4 ° C. per hour is appropriate. If it operates with a fluctuation of about 2 ° C. per hour, the drive source inside the printer moves regardless of printing. Hereinafter, the case where it operates at 4 degreeC or more per hour is demonstrated.

  As shown in FIG. 3, the lowest outside air temperature until that time is one hour after the power is turned on, and the temperature rise for the past one hour is seen after one hour or more after the power is turned on. In general, it is only necessary to make a relative comparison of the temperature one hour ago, but if possible, the minimum outside air temperature of the past one hour is stored, and the difference from this is preferably used. The finer the temperature recording interval, the better every 10 minutes. 3A performs the condensation prevention operation because the temperature rise is 4 ° C. or more in one hour which is a predetermined time, but in the case of B, the condensation prevention operation may be stopped because the temperature rise is small. In the case of C, the condensation prevention operation is required again.

  As described above, the driving signal is output from the calculating means to each driving source using the temperature sensor shown in FIG. 1 under the operating condition shown in FIG. Another embodiment will be described below. In some cases, the drive source is a laser that is a light emitting element in the same optical system. A light emitting element such as a laser and its driver generate heat at the same time, and can contribute to dew condensation prevention operation. However, it generates less heat than a scanner motor, so its use is low.

  Next, there is a developing device as a drive source. Each developing device generates heat due to friction and may be used. When the developing device is driven, the influence on the photosensitive member may be less if it does not contact the photosensitive member.

  The next drive source can drive the transfer belt, which is a photoconductor and an intermediate transfer body, but if there is no positive heat generation, it is better to stop the photoconductor and stop the transfer belt. This prevents toner or the like from adhering to the surface of the photosensitive member or the transfer belt without being able to remove the condensation.

  As another driving source, there are a fixing device and a paper feeding unit. The temperature of the printer can be slightly increased by these drivings. As another embodiment, it is conceivable to operate an erase lamp 8 for erasing the photoreceptor potential. The light is emitted to generate heat, and the photoreceptor and the transfer belt can be prevented from dew condensation.

  The above operation performs the same driving as the driving method of the scanner motor, and warms the inside of the main body while repeating ON and OFF. Another example is to stop the fan. The fans include an optical fan 20, a fixing fan 18, a main body fan 19, and the like, which prevent excessive temperature rise. By stopping the fan, the temperature change inside the printer can be prevented from being influenced by the outside air.

  For example, if the outside air is warm and humid air, the cold main body will be condensed at once when the fan is operated. Therefore, when the printer body is at a low temperature, a method of stopping the fan is appropriate.

  As another example, the fan may be rotated in the reverse direction. In particular, by rotating the fuser fan in the reverse direction, sufficiently warm and low-humidity air can be supplied into the main body. Air flows from the fixing device to the photoconductor and the developing device, and condensation can be prevented.

  Condensation is prevented by warming as described above, but the temperature sensor 16 may be installed inside the main body in order to know the effect. As a result, when the dew condensation prevention operation is insufficient, there is a case where the operation is continuously warmed.

  As described above, it is possible to prevent image defects due to condensation by warming the inside of the main body, but after performing the condensation prevention operation for a predetermined period, the normal operation is resumed. The predetermined period includes the number of print images (for example, 500 images), the elapsed time after power-on (for example, 4 hours), the outside air temperature (for example, 30 degrees or more), and the dew condensation prevention operation is stopped in any case. it can. In addition, the printing operation during the dew condensation operation is basically permitted, and if the temperature rises rapidly, the printing operation may be disabled. It is desirable to stop this condensation prevention operation during the sleep operation.

  In addition to the laser printer, the image forming apparatus can be applied to an image forming apparatus using electrophotography such as a printer such as an LED printer or a copying machine.

It is a block diagram which shows one Example of this invention. It is explanatory drawing which shows the relationship of the ambient temperature rise with respect to a drive source. It is explanatory drawing which shows the relationship between outside temperature and an operating condition. It is a block diagram which shows the other Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 7 Recording medium 10 Developing device 11 Fixing device 13 Exposure device 17 Control means 18, 19, 20 Cooling fan

Claims (7)

An image forming apparatus comprising: an exposure device that forms an electrostatic latent image on a photoconductor; and a developing device that supplies a developer to the photoconductor that holds the electrostatic latent image and forms a developed image on the photoconductor In
An image forming apparatus comprising control means for driving at least one of an exposure device and a developing device in a low temperature environment irrespective of an image forming operation. An image forming apparatus comprising: an exposure device that forms an electrostatic latent image on a photoconductor; and a developing device that supplies a developer to the photoconductor that holds the electrostatic latent image and forms a developed image on the photoconductor In
An image forming apparatus comprising control means for driving at least one of an exposure device and a developing device independently of an image forming operation when a predetermined temperature rises.   3. The image forming apparatus according to claim 1, wherein the exposure device and the developing device are stopped after being driven for a predetermined time.   4. The image forming apparatus according to claim 3, wherein the exposure device and the developing device repeat the driving operation several times. An exposure device that forms an electrostatic latent image on the photoconductor, a developing device that supplies developer to the photoconductor that holds the electrostatic latent image, and that forms a developed image on the photoconductor, and holds the developed image An image forming apparatus comprising: a fixing device that heats the recorded medium and fixes the developed image on the recording medium;
An image forming apparatus comprising: control means for stopping at least one of a fan, an exposure device, and a developing device for cooling a fixing device in a low temperature environment regardless of an image forming operation. An exposure device that forms an electrostatic latent image on the photoconductor, a developing device that supplies developer to the photoconductor that holds the electrostatic latent image, and that forms a developed image on the photoconductor, and holds the developed image An image forming apparatus comprising: a fixing device that heats the recorded medium and fixes the developed image on the recording medium;
And a control unit that drives at least one of a fan, an exposure device, and a developing device for cooling the fixing device in a low temperature environment irrespective of the image forming operation and in a direction opposite to that during the image forming operation. Image forming apparatus. The image forming apparatus according to claim 6, wherein the driving direction is switched to forward rotation after a predetermined period.

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