JP5896620B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus using an electrophotographic method, and more particularly to measures for noise reduction of an image forming apparatus.

  In an image forming apparatus using an electrophotographic process, noise such as paper conveyance sound (bounce sound) and polygon motor wind noise is generated with the recent increase in image processing speed. The bouncing sound is a so-called impulse response in which a high sound is generated instantaneously, and the wind noise of the polygon motor is a high frequency sound, which is very disturbing to the user. In recent years, the demand for noise reduction has increased, and these noise reduction measures have become important.

  However, when the image forming device is isolated in a separate room or when noise is generated due to other factors, image processing speed is given priority over noise reduction measures in environments where noise associated with image formation is not a concern. Sometimes. In addition, even if the noise is unacceptable during the day, it may be annoying to the surroundings at midnight.

  Therefore, an image forming apparatus capable of switching the image processing speed in accordance with the situation has been proposed. Patent Document 1 discloses a first print mode in which a normal print operation is performed when ambient brightness is equal to or higher than a predetermined value. An image forming apparatus is disclosed that operates in the second print mode when the ambient brightness is equal to or less than a predetermined value and the apparatus operating sound is lower than that in the first print mode.

  Further, in Patent Document 2, a plurality of paper transport speeds are set, and the driving means is controlled based on the paper transport speed selected by the operator using the operation unit, and the circumference of the transport roller from the paper feed unit to the registration roller is controlled. An image forming apparatus in which the speed is switched is disclosed. Further, Patent Document 3 discloses an image forming apparatus including a switch for switching the conveyance speed of a sheet conveyance member provided in a sheet reversal conveyance unit for performing image formation on both sides of a sheet in at least two stages. ing.

JP 2005-1255 A JP 2005-200130 A JP 2004-109846 A

  However, in the method of Patent Document 1, in order to reduce the device operation sound according to the ambient brightness, it is not possible to take sufficient measures in a use environment where noise reduction measures are given priority even during the daytime. could not. Further, in the methods of Patent Documents 2 and 3, in order to maintain the image forming efficiency, the conveying speed between the sheet feeding unit and the registration roller, which has little influence on the image forming operation, or the sheet reversing conveying unit is reduced. It is. Therefore, it is insufficient as a countermeasure when the demand for noise reduction is significantly higher than the image forming efficiency.

  On the other hand, if the image formation speed is reduced along with the paper conveyance speed, the wind noise of the polygon motor can be reduced, so that more effective noise reduction can be achieved in usage environments where noise reduction is given priority over image formation efficiency. It becomes a countermeasure. In this case, it is necessary to reduce the rotation speed (the number of rotations per unit time) of the polygon motor, but the polygon mirror is required to rotate with high accuracy. Therefore, a motor capable of maintaining high-precision rotation even when the rotation speed is greatly changed is required, and there is a problem that the cost of the image forming apparatus increases.

  In view of the above problems, the present invention can arbitrarily switch between a mode that prioritizes image formation efficiency and a mode that prioritizes silencing according to the user's usage environment, and a mode that prioritizes silencing is sufficient. An object of the present invention is to provide an image forming apparatus that can reduce noise and reduce costs.

  To achieve the above object, the present invention comprises an image carrier having a photosensitive layer formed on the surface thereof, a charging device for charging the surface of the image carrier, and a polygon mirror for deflecting and scanning beam light emitted from a light source. An exposure apparatus that irradiates a light beam onto the image carrier uniformly charged by the charging device to form an electrostatic latent image on the surface of the image carrier, and an electrostatic latent image formed by the exposure device. A developing device for forming a toner image on the image carrier by attaching toner to the image, and a toner image formed on the image carrier by the developing device on a recording medium directly or via an intermediate transfer member In an image forming apparatus including a transfer unit that transfers and a fixing unit that fixes a toner image transferred onto a recording medium by the transfer unit, a printing speed and a rotation speed of the polygon mirror are set to a constant reference speed. Standard mode A first silent mode in which the printing speed and the rotation speed of the polygon mirror are reduced from the reference speed by a predetermined rate; the printing speed is set to ½ of the reference speed; and the rotation speed of the polygon mirror is equal to the reference speed. A print mode comprising a second silent mode in which the reflecting surface is used while skipping the entire surface and a third silent mode in which the first silent mode and the second silent mode are simultaneously performed can be selectively set. It is a feature.

  According to the present invention, in the image forming apparatus configured as described above, when any one of the first silent mode, the second silent mode, and the third silent mode is selected, the fixing unit corresponds to a decrease in printing speed. The fixing temperature is lowered.

  Further, according to the present invention, in the image forming apparatus having the above configuration, when any one of the first silent mode, the second silent mode, and the third silent mode is selected, the fixing temperature of the fixing unit is decreased. The image density is lowered.

  According to the present invention, in the image forming apparatus configured as described above, the rotational speed of the polygon mirror in the first silent mode is greater than ½ of the reference speed.

  Further, according to the present invention, in the image forming apparatus having the above configuration, an external input unit capable of inputting a print command and print setting from the outside is connected, and the print setting input from the external input unit is set in the image forming apparatus main body. If the print mode is different from the print mode, the print based on the print command is executed with the print setting input from the external input unit, and after the print based on the print command is completed, the print command is set in the image forming apparatus main body. It is characterized by automatically returning to the print mode.

  According to the first configuration of the present invention, when priority is given to image formation efficiency, the standard mode is set. When priority is given to noise reduction, the first mode is selected according to the required level of silence and the type of noise recognized. Any one of the first to third silent modes can be selected and set. Further, since the three-stage silent mode can be set only by changing the rotation speed of the polygon mirror in two stages, the polygon motor can be easily controlled.

  Further, according to the second configuration of the present invention, in the image forming apparatus having the first configuration, when any one of the first to third silent modes is selected, the fixing unit is set according to the decrease in the printing speed. By reducing the fixing temperature, it is possible to reduce power consumption while maintaining the fixing performance at the fixing unit.

  According to the third configuration of the present invention, in the image forming apparatus having the second configuration, when any one of the first to third silent modes is selected, the image density is adjusted according to the decrease in the fixing temperature. By reducing the power consumption, the toner consumption can be reduced in addition to the power consumption, and the operation considering energy saving and resource saving becomes possible.

  According to the fourth configuration of the present invention, in the image forming apparatus having any one of the first to third configurations, the rotational speed of the polygon mirror is always maintained at a speed larger than ½ of the reference speed. However, the printing speed can be reduced to ½ or less of the reference speed. Accordingly, since it is not necessary to use an expensive high-precision motor as the polygon motor, it is possible to improve silence while suppressing an increase in the cost of the image forming apparatus.

  According to the fifth configuration of the invention, in the image forming apparatus having any one of the first to fourth configurations, the print setting input from the external input means is set in the image forming apparatus main body. If it is different from the mode, the printer automatically returns to the print mode set in the main body of the image forming apparatus after printing based on the print command from the external input means is completed. Therefore, interrupt printing can be performed with a desired print setting.

1 is a schematic cross-sectional view showing the overall configuration of an image forming apparatus of the present invention. 1 is a block diagram showing a control path of an image forming apparatus of the present invention. The top view which shows an example of the operation part 60 mounted in the image forming apparatus of this invention 6 is a flowchart showing an example of speed control during image formation in the image forming apparatus of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of the image forming apparatus of the present invention. In FIG. 1, an image forming apparatus 8 (a monochrome multifunction device is shown as an example here) is provided with an image forming section 8 for forming a monochrome image by charging, exposing, developing, and transferring processes.

  Next, the image forming unit 8 will be described. Around the photosensitive drum 1 rotatably disposed, a charging device 2 for charging the photosensitive drum 1, an exposure device (laser scanning unit or the like) 4 for exposing image information to the photosensitive drum 1, and photosensitive A developing device 3 that forms a toner image on the body drum 1 and a cleaning device 5 that removes toner remaining on the photosensitive drum 1 are disposed. Further, a static elimination device (not shown) for removing residual charges on the surface of the photosensitive drum 1 is provided on the downstream side of the cleaning device 5 with respect to the rotation direction of the photosensitive drum 1 (the direction of arrow A in FIG. 1). . An image forming process is performed on the photosensitive drum 1 while rotating the photosensitive drum 1 in the direction of arrow A.

  The paper P on which the toner image is transferred is accommodated in a paper feed cassette 16 at the lower part of the apparatus, and passes through the paper feed roller 12 and the registration roller pair 13 to the nip between the photosensitive drum 1 and the transfer roller 9. It is conveyed.

  The image reading unit 20 includes a scanner lamp that illuminates the document during copying, a scanning optical system equipped with a mirror that changes the optical path of reflected light from the document, and a condensing lens that focuses the reflected light from the document to form an image. , And a CCD sensor or the like (not shown) that converts the imaged image light into an electrical signal. The image signal read by the image reading unit 20 is converted into a digital signal and then sent to the temporary storage unit 94 (see FIG. 2). An operation unit 60 is disposed on the front side of the image reading unit 20.

  When performing the copying operation, the image reading unit 20 reads the image data of the document and converts it into an image signal. On the other hand, in the image forming unit 8 in the main body of the image forming apparatus 100, the photosensitive drum 1 rotating in the direction A in the drawing is uniformly charged by the charging device 2, and the original image data read by the image reading unit 20 is converted into the original image data. An electrostatic latent image is formed on the photosensitive drum 1 by the laser beam from the exposure device 4 based on this, and toner is attached to the electrostatic latent image by the developing device 3 to form a toner image. The toner is supplied to the developing device 3 from the toner container 6.

  The sheet is conveyed from the sheet feeding cassette 16 to the image forming unit 8 via the sheet feeding roller 12, the sheet conveying path 19, and the resist roller pair 13 toward the photosensitive drum 1 on which the toner image is formed as described above. In the image forming unit 8, the toner image formed on the surface of the photosensitive drum 1 by the transfer roller 9 is transferred to the paper. Thereafter, the toner remaining on the surface of the photosensitive drum 1 is removed by the cleaning device 5 in preparation for the subsequent formation of a new electrostatic latent image.

  Then, the paper P is conveyed from the registration roller pair 13 to the nip portion (secondary transfer nip portion) between the transfer roller 9 and the intermediate transfer belt 8 at a predetermined timing, and the toner image is transferred onto the paper P at the nip portion. The paper P on which the toner image is transferred is conveyed to the fixing unit 7.

  The sheet P conveyed to the fixing unit 7 is heated and pressurized when passing through the nip portion (fixing nip portion) of the pair of fixing rollers 14 to fix the toner image on the surface of the sheet P, thereby forming a predetermined image. Is done. The paper P on which the image is formed is distributed in the transport direction by the transport guide member 21 disposed in the branch portion of the paper transport path 19 through the transport roller pair 15 and is sent as it is (or sent to the reverse transport path 23 to both sides. After being copied), the sheet is discharged to the discharge tray 18 via the discharge roller pair 25.

  Specifically, the sheet conveyance path 19 is bifurcated into the left and right forks on the downstream side of the conveyance roller pair 15, and one path (path that branches rightward in FIG. 1) communicates with the discharge tray 18. ing. The other path (the path branched in the left direction in FIG. 1) is configured to communicate with the reverse conveyance path 23.

  The exposure apparatus 4 will be further described with reference to FIG. The exposure device 4 is a light source that emits a light beam modulated based on an image signal, a collimator lens, an aperture, a cylindrical lens (all not shown), and a light beam deflecting means, and is rotated by a polygon motor 55. Thus, a polygon mirror 41, a scanning lens (fθ lens) 43, and a folding mirror 45 that deflect the light beam incident on the reflecting surface at a constant angular velocity are provided.

  The light beam emitted from the light source is made into a substantially parallel light beam by the collimator lens, and after the beam light that has become the substantially parallel light beam is made a predetermined optical path width by the aperture, it is converted into a cylindrical lens having refractive power only in the sub-scanning direction. Incident. The parallel light beam incident on the cylindrical lens is in the state of a parallel light beam as it is in the main scanning section, converged and emitted in the sub-scanning direction, and is incident on the reflection surface (deflection surface) of the polygon mirror 41. The incident light beam is deflected at a constant angular velocity by the polygon mirror 41 and then deflected at a constant velocity by the scanning lens 43. Then, the light beam deflected at a constant speed is folded back a predetermined number of times by a folding mirror 45 which is a reflecting means arranged in the optical path, and then irradiated onto the surface of the photosensitive drum 1.

  Next, the control path of the image forming apparatus of the present invention will be described. FIG. 2 is a block diagram showing an example of a control path used in the image forming apparatus of the present invention. It should be noted that since various control of each part of the apparatus is performed when the image forming apparatus 100 is used, the control path of the entire image forming apparatus 100 becomes complicated. Therefore, here, a portion of the control path that is necessary for the implementation of the present invention will be mainly described.

  The control unit 90 includes a central processing unit (CPU) 91 as a central processing unit, a read only memory (ROM) 92 that is a read-only storage unit, a random access memory (RAM) 93 that is a read / write storage unit, A plurality of (two in this case) that transmit control signals to and receive input signals from the operation unit 60, such as a temporary storage unit 94 that stores image data and the like, a counter 95, and each device in the image forming apparatus 100. The I / F (interface) 96 is provided. Further, the control unit 90 can be arranged at an arbitrary location inside the apparatus main body.

  The ROM 92 stores a control program for the image forming apparatus 100, data necessary for control, and the like that are not changed during use of the image forming apparatus 100. The RAM 93 stores necessary data generated during the control of the image forming apparatus 100, data temporarily required for controlling the image forming apparatus 100, and the like. The counter 95 adds up the number of printed sheets and counts it.

  In addition, the control unit 90 transmits a control signal from the CPU 91 to the respective units and apparatuses in the image forming apparatus 100 through the I / F 96. In addition, a signal indicating the state and an input signal are transmitted from each part or device to the CPU 91 through the I / F 96. Examples of each part and device controlled by the control unit 90 include the image forming unit 8, the exposure device 4, the fixing unit 7, the transfer roller 9, the image reading unit 20, the motor control circuit 51, and the operation unit 60.

  The operation unit 60 is provided with a liquid crystal display unit 61, a function setting key 62, a numeric keypad 63, and a silence setting key 64, and the user operates the operation unit 60 to input an instruction so that the image forming apparatus 100 can be operated. Various settings are made and various functions such as image formation are executed. FIG. 3 is a plan view of the operation unit 60. The liquid crystal display unit 61 displays the setting mode of the image forming apparatus 100, the image forming status, the number of copies to be printed, and the like. The function setting key 62 selects and sets various functions such as a copy function, a printer function, a scan function, and a facsimile function. The numeric keypad 63 is used to set the number of copies to be printed or to input the fax number of the other party when the facsimile mode is set. The silent setting key 64 is used when setting a silent mode (described later).

  In addition, the operation unit 60 includes functions such as double-sided printing and black-and-white reversal, function keys for performing various settings such as magnification setting and density setting, a start button for instructing the user to start image formation, and when stopping image formation. And a stop / reset button used for setting various settings of the image forming apparatus 100 to a default state.

  A personal computer 50 is connected to the I / F 96. When the printer function is selected by the function setting key 62, various settings of the image forming apparatus 100 can be input from the printer driver of the personal computer 50. That is, the personal computer 50 functions as an external input unit that inputs print settings and print commands from the outside of the image forming apparatus 100.

  The motor control circuit 51 is connected to the drum motor 52, the development motor 53, the cleaning motor 54, the polygon motor 55, the transfer drive motor 56, and the fixing drive motor 57, and each of the motors 52 to 57 is output by an output signal from the control unit 90. Control the drive.

  These motors 52 to 57 are cleaned by the control signal from the motor control circuit 51, the drum motor 52 cleans the photosensitive drum 1, and the developing motor 53 cleans the stirring and conveying screw, magnetic roller and developing roller in the developing device 3. The motor 54 is a cleaning roller and a collecting screw in the cleaning device 5, the polygon motor 55 is the polygon mirror 41, the transfer drive motor 56 is the transfer roller 9, and the fixing drive motor 57 is the fixing roller pair 14. Drive with.

  The image forming apparatus according to the present invention can selectively execute a standard mode in which priority is given to image formation efficiency (number of printed sheets) and a silent mode in which quietness is given priority over image formation efficiency by a user operation.

  In the standard mode, the paper transport speed (printing speed) in the paper transport path from the paper feed cassette 16 to the discharge tray 18 (see FIG. 1) and the rotation speed of the polygon mirror 41 are set to a constant speed (reference speed). It is. The printing speed includes the linear speed of the transport roller including the paper feed roller 12, the registration roller pair 13, and the discharge roller pair 25 arranged in the paper transport path, the photosensitive drum 1 used for the image forming operation, and the developing device 3 (development). Roller), cleaning device 5 (cleaning roller), fixing device 7 (fixing roller pair 14) and other members used for image formation, and the driving speed (linear speed) of the device.

  In the silent mode, the printing speed is decreased from the reference speed at a predetermined rate. The driving of the polygon mirror 41 when the silent mode is executed will be described later.

  Next, the silent mode executed in the image forming apparatus of the present invention will be specifically described. The silent mode is a first silent mode in which the printing speed and the rotation speed of the polygon mirror 41 are reduced to a predetermined ratio larger than ½ of the normal speed (reference speed), and the printing speed is set to ½ of the reference speed. The rotational speed of the polygon mirror 41 is composed of a second silent mode in which the reflection surface is used while skipping the surface while maintaining the reference speed, and a third silent mode in which the first silent mode and the second silent mode are simultaneously performed. The first to third silent modes can be set by the number of times the silent setting key 64 (see FIG. 3) is pressed. For example, the first silent mode is set when the silent setting key 64 is pressed once, the second silent mode is set when pressed twice, the third silent mode is set when pressed three times, and the third silent mode is set.

  For example, in the first silent mode, the printing speed is set to 3/4 of the reference speed (3/4 speed), and the rotational speed of the polygon motor 55 is also reduced to the normal 3/4 according to the printing speed. In the second silent mode, the printing speed is set to 1/2 of the reference speed (1/2 speed), and the rotation speed of the polygon motor 55 is not decreased, and the reflection surface is skipped. In the third silent mode, the printing speed is set to the 3 / 8th speed (3/4 speed × 1/2 speed) of the reference speed, and the rotation speed of the polygon motor 55 is reduced to the normal 3/4 to use the entire surface. .

  When the first silent mode is selected, since both the printing speed and the rotational speed of the polygon motor 55 are reduced to 3/4, the polygon mirror 41 is added to the sheet conveying sound, each member used for image formation, and the driving sound of the apparatus. Wind noise (high-frequency sound) can be reduced. Therefore, it is effective as a noise reduction measure when the wind noise of the polygon mirror 41 is anxious.

  When the second silent mode is selected, the rotation speed of the polygon motor 55 does not decrease, but the printing speed decreases to ½. Therefore, the sheet conveyance sound and the driving sound of the apparatus are more worrisome than the wind noise of the polygon mirror 41. This is effective as a noise reduction measure.

  When the third silent mode is selected, the printing speed is reduced to 3/8 speed, and the rotation speed of the polygon motor 55 is reduced to 3/4. Therefore, the number of print processing sheets is 3/8 (normally 25 sheets / min. Is 9 sheets / min), but it is effective as a noise reduction measure when the noise reduction is required more than in the first and second noise reduction modes.

  Further, in the first to third silent modes, the decrease in the rotational speed of the polygon motor 55 is a normal 3/4 at the maximum. In other words, while maintaining the rotation speed of the polygon motor 55 that requires high-precision rotation at 3/4 or higher, the printing speed is reduced to three stages of 3/4 speed, 1/2 speed, and 3/8 speed. Can be made. Therefore, since it is not necessary to use an expensive high-precision motor as the polygon motor 55, it is possible to improve the quietness while suppressing the cost increase of the image forming apparatus 100.

  Although the printing speed in the first silent mode is 3/4 of the reference speed here, the printing speed is not limited to this, and the printing speed can be reduced at a predetermined rate. However, when the printing speed is reduced to ½ or less of the reference speed, it is necessary to reduce the rotational speed of the polygon motor 55 to ½ or less, and the rotational accuracy of the polygon motor 55 may be lowered. Therefore, it is preferable that the printing speed in the first silent mode is a speed smaller than the reference speed and larger than ½ of the reference speed.

  By the way, when the printing speed is lowered, the rotation speed of the fixing roller pair 14 through which the paper passes is also lowered. As a result, it takes a long time for the paper on which the toner image is formed to pass through the nip portion of the fixing roller pair 14, so that the toner image can be fixed at a temperature lower than the normal fixing temperature. Accordingly, by reducing the fixing temperature stepwise in accordance with the rate of decrease in the printing speed in the first to third silent modes, the power consumption in the fixing unit 7 can be reduced, and the running of the image forming apparatus 100 can be reduced. Costs can be reduced and energy can be saved.

  Further, by reducing the image density (toner adhesion amount per unit area) stepwise as the fixing temperature decreases, the toner consumption can also be reduced. As a result, the replacement cycle of the toner container 6 becomes longer, the running cost of the image forming apparatus 100 is further suppressed, and the operation in consideration of the environment is possible.

  When lowering the fixing temperature and the image density, it is necessary to select a temperature and density in a range that does not affect the image quality of the output image. For example, assuming that the fixing temperature in the standard mode is 195 ° C. and the image density is 100%, in the case of a character image, the fixing temperature is 180 ° C. and the image density is 90 ° in the first silent mode in which the printing speed is reduced to 3/4 speed. %. In the second silent mode in which the printing speed is reduced to 1/2 speed, the fixing temperature is reduced to 170 ° C. and the image density is reduced to 80%. In the third silent mode in which the printing speed is reduced to 3/8 speed, the fixing temperature is reduced to 160 ° C. and the image density is reduced to 70%.

  FIG. 4 is a flowchart showing an example of control during image formation of the image forming apparatus of the present invention. The image forming procedure will be described along the steps of FIG. 4 with reference to FIGS. First, when printing is started by the user (step S1), the control unit 90 determines whether or not individual print settings are input from the personal computer 50 (step S2). If no individual setting has been input, it is then determined whether the silent mode is set by the silent setting key 64 (step S3).

  Next, a control signal is transmitted from the control unit 90 to the motor control circuit 51, and the motors 52 to 57 rotate at a predetermined speed. Then, the respective devices and members used for image formation are driven by the motors 52 to 57 at a predetermined speed, and printing is performed at a predetermined printing speed.

  If the silent mode is not set in step S3, the standard mode is set, so printing is performed at a normal speed (for example, 25 sheets / min) (step S4). If the silent mode is set, printing is performed at a printing speed reduced by a predetermined rate from the reference speed (step S5). For example, when the first silent mode is set, the reference speed is 3/4 speed (18 sheets / min), and when the second silent mode is set, the reference speed is 1/2 speed (12 sheets). / Min) and the second silent mode is set, printing is performed at the reference speed of 3/8 speed (9 sheets / min). In addition, when a decrease in fixing temperature and a decrease in image density are also set in each silent mode, printing is performed at a predetermined fixing temperature and image density.

  On the other hand, if individual print settings are input from the personal computer 50 in step S2, printing is performed at the settings (print speed) input from the personal computer 50 (step S6). Then, after the printing is completed, the print setting is returned to the main unit setting (step S7). For example, if the silent mode has been set before the start of printing, the mode is returned to the silent mode, and if the standard mode has been set, the mode is returned to the standard mode.

  According to the above procedure, the first to third silent modes can be set simply by pressing the silent setting key 64, so that the user's desired silent performance can be selected from the three levels (four levels including the standard mode). The printing speed can be selected. Also, by reducing the fixing temperature and image density according to the printing speed of each silent mode, it is possible to reduce power consumption and toner consumption, and it is possible to operate in consideration of the environment in addition to noise reduction. .

  In addition, when individual print settings are input from the personal computer 50, only the print operation (job) is valid for the input print settings, and after the completion of printing, the settings of the image forming apparatus 100 main body are restored. The interrupt printing can be performed with the desired print setting without changing the main body setting each time.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, the present invention is not limited to the monochrome MFP as shown in FIG. 1, but is also applied to other image forming apparatuses such as a tandem type or rotary type color copying machine, a color printer, a monochrome copying machine, a monochrome printer, and a facsimile. Is possible.

  The present invention is applicable to an image forming apparatus using an electrophotographic process. By using the present invention, it is possible to arbitrarily switch between a mode that prioritizes image formation speed and a mode that prioritizes silencing according to the user's usage environment, and sufficient silencing is possible in modes that prioritize silencing In addition, an image forming apparatus with reduced cost can be provided.

1 Photosensitive drum (image carrier)
2 Charging Device 3 Developing Device 4 Exposure Device 5 Cleaning Device 7 Fixing Unit 8 Image Forming Unit 9 Transfer Roller (Transfer Unit)
41 Polygon mirror 50 PC (external input means)
DESCRIPTION OF SYMBOLS 51 Motor control circuit 52 Drum motor 53 Developing motor 54 Cleaning motor 55 Polygon motor 56 Transfer drive motor 57 Fixing drive motor 60 Operation part 64 Silent setting key 90 Control part 100 Image forming apparatus

Claims (4)

An image carrier having a photosensitive layer formed on the surface;
A charging device for charging the surface of the image carrier;
A polygon mirror that deflects and scans the beam light emitted from the light source is provided, and the image carrier uniformly charged by the charging device is irradiated with the light beam to form an electrostatic latent image on the surface of the image carrier. An exposure device;
A developing device for forming a toner image on the image carrier by attaching toner to the electrostatic latent image formed by the exposure device;
Transfer means for transferring the toner image formed on the image carrier by the developing device onto a recording medium directly or via an intermediate transfer body;
A fixing unit for fixing the toner image transferred onto the recording medium by the transfer unit;
In an image forming apparatus comprising:
A standard mode in which the printing speed and the rotation speed of the polygon mirror are set to a constant reference speed, and a printing speed and a rotation speed of the polygon mirror are decreased from the reference speed to a predetermined speed higher than ½ of the reference speed . The first silent mode, the second speed mode in which the printing speed is set to ½ of the reference speed, the polygon mirror is rotated at the reference speed and the reflection surface is skipped, and the first printing speed is set to the first speed. It is possible to selectively set a print mode comprising a third silent mode in which the reflection speed is set to 1/2 while the polygon mirror is rotated in the first silent mode while the rotational speed of the polygon mirror is set to 1/2 of the silent mode. An image forming apparatus.   The fixing temperature of the fixing unit is decreased according to a decrease in printing speed when any one of the first silent mode, the second silent mode, and the third silent mode is selected. The image forming apparatus according to 1.   The image density is decreased according to a decrease in fixing temperature of the fixing unit when any one of the first silent mode, the second silent mode, and the third silent mode is selected. The image forming apparatus according to 2. External input means that can input print commands and print settings from outside is connected.
When the print setting input from the external input unit is different from the print mode set in the image forming apparatus main body, printing based on the print command is executed with the print setting input from the external input unit, and the print 4. The image forming apparatus according to claim 1 , wherein after the printing based on the command is completed, the image forming apparatus automatically returns to the printing mode set in the image forming apparatus main body .

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