JP5668427B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Image forming apparatuses that use toner to form an image widely use an image carrier that has a photoreceptor layer on an endless peripheral surface. This image carrier is exposed on the basis of image information after the peripheral surface is charged, and a latent image is formed by the difference in electrostatic potential. The toner is transferred to the image portion of the latent image to visualize the image. The visualized toner image is directly transferred from the image carrier directly to the recording medium or from the image carrier to the intermediate transfer member, and then further transferred to the recording medium. Then, the toner image on the recording medium is heated and fixed on the recording medium.

  For the exposure of the image carrier, many exposure apparatuses using laser light are employed. This exposure apparatus irradiates a rotating polygonal mirror with a flashing laser beam based on image information, rotates the laser beam whose incident angle on the mirror surface fluctuates, and scans the peripheral surface of the image carrier. The rotary polygon mirror has a plurality of mirror surfaces around it and is driven to rotate around a central axis by a motor. When the rotary polygon mirror starts driving from a stationary state, it takes time to reach the scanning speed of the laser beam, and when the image forming operation starts, the rotary polygon mirror starts driving in advance. Is done.

  On the other hand, as a fixing device that fixes a toner image transferred onto a recording medium to the recording medium, a fixing device that heats and fixes the toner image in contact with the recording medium is widely used. The fixing member includes a heating unit, and it takes time to heat the fixing member to a temperature at which the toner image can be fixed. For this reason, preheating is performed during standby, and heating by the heating unit is started in advance before the image forming operation is started.

  As described above, when the rotation of the rotary polygon mirror is maintained so that the image carrier can be exposed and the temperature of the fixing member is maintained so that the toner image can be fixed, the image forming operation starts immediately. However, if the rotating polygon mirror rotates and the fixing member is heated for a long time, the amount of power consumed increases. Also, if the operator starts to rotate the polygon mirror and starts heating from the standby temperature of the fixing member immediately after or immediately before trying to form an image, the exposure and fixing cannot be performed immediately, and the first image is formed. It takes a long time to do so. For this reason, for example, Patent Document 1 proposes a method for shortening the time until the first image is formed and reducing power consumption.

Japanese Patent Application Laid-Open No. 07-036353

  SUMMARY An advantage of some aspects of the invention is that it is possible to reduce both the time required for forming the first image after the operation of the image forming apparatus is paused and the reduction of power consumption.

  In order to solve the above-mentioned problems, an invention according to claim 1 includes an image holding body on which a latent image is formed due to a difference in electrostatic potential between an exposed portion and a non-exposed portion, a plurality of mirrors around the motor, and a motor An exposure apparatus that irradiates a rotating polygon mirror that is rotationally driven by a laser beam that blinks based on image information and that scans and exposes the laser beam reflected by the rotating polygon mirror on the image carrier; and A developing device that transfers toner to a latent image on the image carrier formed by exposure by the apparatus and develops it, and an image (hereinafter referred to as a toner image) formed by adhesion of toner formed on the image carrier is directly Alternatively, a fixing device that contacts and heats the recording medium transferred via the intermediate transfer member, a heating unit that heats the fixing member that contacts the recording medium of the fixing device, and a temperature of the fixing member With temperature sensor to detect A human detection sensor that detects a person approaching, and a control device that controls at least heating by the heating means and rotational driving of the motor, wherein the control device is configured to control the temperature when the power is on. The heating means is controlled with a detection value of the sensor as a target at a first temperature set in advance, and when the human detection sensor detects a state where a person is approaching, driving of the motor is started. A second temperature that is higher than the first temperature is set as a target temperature for controlling the heating means when a predetermined time C elapses while the detection sensor detects a state where a person is approaching. The present invention provides an image forming apparatus characterized in that

  The invention according to claim 2 is the image forming apparatus according to claim 1, wherein the human detection sensor includes a light emitting portion and a light receiving portion, and light emitted from the light emitting portion is reflected by a person, Assume that a state in which a person is approaching is detected by a change in time until light is received by the light receiving unit.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, after the image forming operation is started and the image forming operation is ended, or the temperature targeted for the control is changed to the second temperature. After that, when the predetermined time A2 has elapsed without the input of the signal to start the next image forming operation, if the person detection sensor has not detected a person, the control When the target temperature is changed to the first temperature and the human detection sensor detects a person, the target temperature for the control is maintained at the second temperature to detect the person. It is assumed that the driving of the motor is stopped when a predetermined time B2 elapses after it has disappeared.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the first aspect, the human detection sensor includes a sound collecting device, and detects that a repeated sound or a continuous sound in the collected sounds increases. It is assumed that a person is approaching.

  In the image forming apparatus according to the first aspect, compared to an image forming apparatus that does not include this configuration, the time from when the operation of the image forming apparatus is paused to when the first image is formed can be shortened. it can.

  In the image forming apparatus according to the second aspect, it is possible to discriminate and detect a person approaching the image forming apparatus and a person who only passes.

  In the image forming apparatus according to claim 3, compared with an image forming apparatus that does not include this configuration, the time until the next image is formed after the image forming operation is completed, and the power consumption is reduced. It is possible to achieve both.

  In the image forming apparatus according to the fourth aspect, it is possible to discriminate and detect a person approaching the image forming apparatus and a person who only passes.

1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram showing a reference example over time of temperature control of a heating roll of a fixing device and control of a motor that drives a rotary polygon mirror of an exposure device in the image forming apparatus shown in FIG. 1. FIG. 2 is a diagram illustrating, over time, temperature control of a heating roll and control of a motor that drives a rotary polygon mirror in the image forming apparatus illustrated in FIG. 1, and illustrates a reference example of control when an image forming operation is not performed. FIG. FIG. 2 is a diagram showing a reference example of the temperature control of the heating roll when the image forming apparatus shown in FIG. 1 functions as a printer or a facsimile and the control of the motor that drives the rotary polygon mirror over time. FIG. 5 is a diagram illustrating, over time, temperature control of a heating roll of a fixing device and control of a motor that drives a rotary polygon mirror of an exposure device in an image forming apparatus that is an embodiment of the present invention . FIG. 6 is a diagram illustrating the temperature control of the heating roll and the control of the motor that drives the rotary polygon mirror over time in the image forming apparatus according to the embodiment of the present invention, and a diagram illustrating when the image forming operation is not performed. is there.

Hereinafter, embodiments of the invention according to the present application will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.
This image forming apparatus includes an image reading unit 1 and an image forming unit 2 and functions as a copying machine. That is, an image optically read by the image reading unit 1 is converted into an electrical image signal, and the image forming unit can form an image on a recording medium based on the image signal. The image forming unit can also form an image based on a signal input from an external device, and functions as a printer or a facsimile.

The image reading unit 1 includes an image detection unit in which the exposure lamp 11 and the image reading sensor 14 are housed, and a document holding unit that holds a document to be read.
The image detection unit irradiates the document with reading light from the exposure lamp 11 and guides the reflected light to the image reading sensor 14 via the reflecting mirror 12 and the lens 13. Then, it is converted into an electrical signal by the image reading sensor 14.
The document holding unit includes a platen glass 15 that comes into contact with the document surface to be read, a document cover 16 that suppresses the document placed thereon, and a document feeding device 17 that transports the document and passes the position exposed by the exposure lamp 11. And. The document holding section is operated when the document cover 16 is pushed up to open the upper surface of the platen glass 15 or is closed to suppress the document, or when the document is set on the document feeder 17. When this occurs, this can be detected and a detection signal can be output.

  An operation panel and a display screen (not shown) are provided on the front side of the image reading unit to input signals necessary for operation of the image forming apparatus, display necessary for signal input, and the like. It has become.

The image forming unit 2 forms a color image using four color toners, and outputs an image of each color of yellow (Y), magenta (M), cyan (C), and black (K). Photographic image forming units 20Y, 20M, 20C, and 20K, and an intermediate transfer belt 31 facing these units are provided. The intermediate transfer belt 31 is stretched so as to face each of the image forming units 20, and the peripheral surface is driven to rotate. In order from the upstream side in the circumferential movement direction of the intermediate transfer belt 20, an image forming unit 20Y that forms a yellow toner image, an image forming unit 20M that forms a magenta toner image, and an image forming unit 20C that forms a cyan toner image. An image forming unit 20K for forming a black toner image is arranged, and on the downstream side thereof, a secondary transfer roll 35 for performing secondary transfer is disposed so as to face the intermediate transfer belt 31. A sheet-like recording medium is fed from the sheet storage portion 42 to the secondary transfer position where the secondary transfer roll 35 faces the intermediate transfer belt 31 through the conveyance path 41. On the downstream side of the secondary transfer position in the recording medium conveyance path, a recording medium conveyance device 36 to which the toner image has been transferred and a fixing device 37 that heats and pressurizes the toner image and presses the toner image onto the recording medium are provided. Yes. Further, a paper discharge holding unit 39 is provided on the downstream side to hold the recording medium on which the toner image is fixed in an overlapping manner.
Further, a human detection sensor 40 is provided on the front side of the image forming unit 2, that is, on the surface facing the position where the operator operates the image forming apparatus.
Further, the image forming unit 2 is provided with a control device 43 that controls the operation of each unit.

  Each of the image forming units 20 has a photosensitive drum 21 that functions as an image holding member with an electrostatic latent image formed on the surface thereof, and around each photosensitive drum 21, A charging device 22 for charging the surface, a developing device 23 for selectively transferring toner to a latent image formed on the photosensitive drum to form a toner image, and a toner image on the photosensitive drum 21 being transferred to an intermediate transfer belt A primary transfer roll 24 that performs primary transfer onto 31 and a cleaning device 25 that removes toner remaining on the photosensitive drum after transfer are provided. Further, each charged photosensitive drum 21 is provided with an exposure device 26 that emits image light based on an image signal, and the photosensitive drum 21 is irradiated with image light upstream of the position where the developing device 25 faces. To write an image.

  The photoreceptor drum 21 is formed by laminating an organic photoreceptor layer on the peripheral surface of a metal cylindrical member, and the metal portion is electrically grounded. Further, a bias voltage may be applied.

  The charging device 22 has an electrode wire stretched with a space from the surface of the photosensitive drum 21, and corona discharge is generated between the electrode wire and the surface of the photosensitive drum 21 to thereby generate a photosensitive drum. The surface of 21 is charged. Instead of the charging device, a roll-shaped member that comes into contact with the surface of the photosensitive drum may be used, and discharge may be generated in a minute gap with respect to the photosensitive drum 1.

  The developing device 23 uses a two-component developer containing toner and a magnetic carrier, is supported at a position facing the photosensitive drum 1, and transfers the toner to an image portion on the photosensitive drum 1. The latent image is visualized.

  The primary transfer roll 24 is formed by coating the outer peripheral surface with a rubber material in which conductive particles are added to a metal core, and the image forming units 20Y, 20M, 20C, and 20K are opposed to the photosensitive drum 21. It is arranged on the back side of the intermediate transfer belt 31 at the position. Then, a transfer bias voltage is applied between the primary transfer roll 24 and the photosensitive drum 21, and the toner image on the photosensitive drum is electrostatically transferred to the passing intermediate transfer belt 31 at the primary transfer position where they face each other. Is to be transferred to.

  The cleaning device 25 removes toner remaining on the photosensitive drum after transfer by a cleaning blade and a cleaning brush arranged in contact with the peripheral surface of the photosensitive drum 1.

  The exposure device 26 generates a flashing laser beam based on an image signal, and scans this in the main scanning direction (axial direction) of the photosensitive drum 1 by a rotating polygon mirror 27 (polygon mirror). The rotary polygon mirror 27 has a plurality of mirror surfaces around it, and is driven to rotate around the central axis by a motor 28. The laser beam incident on the mirror surface is scanned on the photosensitive drum by changing the angle of the mirror surface. As a result, electrostatic latent images corresponding to the images of the respective colors are formed on the surfaces of the respective photosensitive drums 21.

The intermediate transfer belt 31 is formed by endlessly forming a film-like member in which a plurality of layers are stacked. Each layer has a predetermined surface resistivity, for example, by adding a substance for imparting conductivity such as carbon or an ion conductive substance to a resin material such as polyimide, polyamideimide, polycarbonate, or fluorine resin. Have been adjusted so that.
Such an intermediate transfer belt 31 is stretched around a drive roll 32 that is rotationally driven, an adjustment roll 33 that adjusts the deviation of the intermediate transfer belt 31 in the width direction, and a counter roll 34, and is shown in FIG. It moves around in the direction of arrow A.

  The secondary transfer roll 35 disposed at a position facing the opposing roll 34 and the intermediate transfer belt 31 forms an outer peripheral layer of rubber material to which conductive particles are added on the outer peripheral surface of the metal core material. It is a thing. A transfer bias voltage for forming an electric field for transfer is applied between the secondary transfer roll 35 and the counter roll 34. This transfer vise voltage is applied so that the potential of the opposing roll 34 is on the same polarity side as the toner.

  The facing roll 34 is formed by forming an outer peripheral layer on the outer peripheral surface of a metal core, and the outer peripheral layer is formed of silicone rubber, urethane rubber, EPDM or the like to which conductive particles such as carbon black are added. can do.

  The fixing device 37 includes a heating roll 37a incorporating a halogen lamp as a heating source and a pressure roll 37b pressed against the heating roll 37a, and these are in contact with each other to form a nip portion. . The recording medium onto which the toner image has been transferred is fed into the nip portion and heated and pressurized between the heated heating roll 37a and the pressure roll 37b, and the toner image is pressed onto the recording medium. Has become. As the heating source of the heating roll 37a, various sources that can heat the heating roll 37a to a temperature at which the heating roll 37a can be fixed, such as a resistance wire that generates heat, an electromagnetic induction heating device, and the like can be adopted in addition to the halogen lamp. Then, by controlling the ON / OFF of such heating means, the temperature is adjusted to a predetermined temperature.

The human detection sensor 40 can detect a person approaching the front side of the image forming apparatus, and can employ a person that optically detects a person, a person that detects a person by sound, or the like. it can. An optically detecting person is provided with a light emitting part and a light receiving part, and the presence of a person is detected when light emitted from the light emitting part, for example, a light pulse is reflected by the person and detected by the light receiving part. To do. The distance can be detected by the time from light emission to light reception. Further, it is determined that the person is approaching when it is detected that the time until the light emitted from the light emitting unit is received by the light receiving unit gradually decreases. Accordingly, it is possible to discriminate between a person who passes near the image forming apparatus and a person who approaches to operate the image forming apparatus.
In addition, the detection by sound is provided with a sound collecting device that collects sound generated by the movement of a person or the like, and it can be determined that the person is approaching by detecting the increase in sound. For example, repeated sounds such as footsteps and continuous sounds such as speaking voice are collected, and it is detected that this sound is increasing. As a result, it is possible to discriminate between sudden sounds and irregular sounds and sounds approaching people. It can also be determined from the frequency of the sound that is generated outside the audible range and reflected by a person.

The control device 43 controls the operation of each part of the image forming unit 2. And the detection signal by the said human detection sensor 40, the signal to the effect that the image reading part 1 was operated, and the signal from an operation panel are input. The signal indicating that the image reading unit 1 has been operated is sent when the document cover 16 is pushed up so as to open the upper surface of the platen glass 15 or is closed so as to suppress the document, or the document is fed. This is a signal that is detected and output when a document is set on the apparatus 17. Based on these signals, the start of the motor 28 that drives the rotary polygon mirror 27 of the exposure device 26 and the temperature control of the heating roll 37a can be performed before the image forming operation is started in the image forming unit 2. It is possible. On the other hand, even after the image forming operation is completed, the timing for stopping the driving of the motor 28 and the temperature control of the heating roll 37a are performed.
Note that the start of the image forming operation is a time when a signal to start the image forming operation is input, and the photosensitive drum 21 is activated based on the start signal to start exposure or the like. . Further, at the end of the image forming operation, the fixing of the toner image formed on the recording medium is completed and the recording medium is discharged. For example, a sensor 44 for detecting the recording medium is provided in the discharge path. The time when the passage of the rear end of the recording medium is detected can be the end of the image forming operation.

A reference example of the operation of such an image forming apparatus will be described next.
As shown in FIG. 2, when the main power supply is turned on, power is supplied to a halogen lamp that is a heating source of the fixing device 37, and the heating roll 37a is heated. Then, ON / OFF of power supply is controlled with a predetermined first temperature as a target. For example, an upper control value and a lower control value are set above and below the first temperature. When the detected value of the temperature sensor 38 exceeds the upper control value, the halogen lamp is turned off, and when the detected temperature decreases and falls below the lower control value. Turn on. The control upper value and the control lower value may be set to other values such as setting the control upper value to a temperature higher than the first temperature as the control lower value. The first temperature is set as a standby temperature, and when the main power supply is turned on and no image forming operation is performed, the temperature of the heating roll 37a detected by the temperature sensor 38 is the first temperature. The temperature is maintained in a control range targeted by the temperature, that is, a range controlled by the control upper value and the control lower value. Here, the temperature within the control range includes a temperature higher than an upper control value and a temperature lower than a lower control value caused by a time lag between ON / OFF of power supply and the detected temperature. That is, the range in which the temperature sensor detects the control upper value and the power supply is cut off and then becomes higher than the control upper value, and the temperature sensor detects the control lower value and the power supply is started and then the temperature is lower than the control lower value. including.

  When the detected temperature of the heating roll 37a is maintained within the control range targeting the first temperature and the person detection sensor 40 detects that a person approaches the image forming apparatus in the standby state, this signal is The motor 28 of the rotary polygon mirror 27 is activated by being input to the control device 43. When the rotary polygon mirror 27 is activated, the rotation speed gradually increases and the surface of the photosensitive drum 21 can be exposed. Thereafter, when the image reading unit or the like is operated by a person approaching the image forming apparatus, that is, an operator who uses the image forming apparatus as a copying machine, a signal to that effect is input to the control device 43 and the heating roll 37a The target temperature for controlling the temperature (control temperature) is changed from the first temperature to the second temperature higher than this. Then, based on the temperature detected by the temperature sensor 38, control is performed to turn the halogen lamp on or off with the second temperature as a target. The second temperature is set as a temperature at which the image forming operation can be started. If the temperature is equal to or higher than the second temperature, the image forming operation is started and the recording medium reaches the fixing device. The heating roll 37a can be heated to a third temperature set as a temperature capable of fixing. Note that the control upper value and the control lower value are also set in advance for the second temperature and the third temperature, respectively, and the detected temperature is compared with the control upper value and the control lower value in the same manner as the first temperature. The heating is controlled.

  As described above, the control target temperature is changed from the first temperature to the second temperature when the image reading unit is operated, that is, when the document cover is opened, the document feeder. When a document is placed on the screen, any one of the keys, buttons, etc. on the operation panel is operated. Further, other settings may be added.

  When the control target temperature is set to the second temperature and a signal for starting the image forming operation is input, for example, when the start button on the operation panel is pressed, the image forming operation starts. Then, an image is formed based on the image signal read by the image reading unit 1. At the same time, the target temperature of the heating roll 37a, that is, the control temperature is changed from the second temperature to the third temperature. However, if the rotation of the rotary polygon mirror 27 has not reached the exposure speed when the start button is pressed, or the temperature of the heating roll 37a has not reached the second temperature, the holding state is set. The image forming operation is not started, and the rotational speed of the rotary polygon mirror 27 becomes a speed at which exposure is possible, and the image forming operation is started after the heating roll 37a reaches the second temperature.

  When the image forming operation is started, the photosensitive drums 21 are rotationally driven, and the surface of each photosensitive drum 21 is charged by the charging device 22. Then, a flashing laser beam is output from the exposure device 26 based on the image data, and scanned on the photosensitive layer on the surface of the photosensitive drum 21. As a result, the potential of the laser light irradiation position is attenuated, and an electrostatic potential difference is generated between the exposed position and the unexposed position, and a so-called electrostatic latent image is formed on the surface of the photosensitive drum 21. Is done.

  The electrostatic latent image formed on the photosensitive drum 21 in this way is conveyed to a developing position facing the developing device 23 by the rotation of the photosensitive drum 21. When passing through the developing position, the toner is electrostatically transferred from the developing roll provided in the developing device 23 to the image portion on the surface of the photosensitive drum, and a toner image is formed.

  At the primary transfer position, the photosensitive drum 21 and the primary transfer roll 24 face each other via the intermediate transfer belt 31, and a transfer bias voltage is applied between them. By applying the transfer bias voltage, an electrostatic force acts on the toner in an electric field formed between the photosensitive drum 21 and the primary transfer roll 24, and the toner image on the surface of the photosensitive drum 21 becomes a surface of the intermediate transfer belt 31. Is transferred to. The intermediate transfer belt 31 is sequentially opposed to the respective image forming units 20 to transfer the toner images of the respective colors in a superimposed manner. The intermediate transfer belt 31 onto which the toner image has been transferred in multiple rotations moves in the direction of arrow A shown in FIG. 1, and the opposing roll 34 that contacts the inner surface of the intermediate transfer belt 31 and the secondary transfer roll 35 face each other. The toner image is conveyed to the next transfer position.

The recording medium P is fed between the secondary transfer roll 35 and the intermediate transfer belt 31 in accordance with the timing at which the toner image on the intermediate transfer belt 31 is conveyed, and the secondary transfer bias voltage is set to the secondary transfer roll 35. And the counter roll 34. The electrostatic force acts on the toner in the electric field formed at this time, and the toner image on the surface of the intermediate transfer belt 31 is transferred to the recording medium P.
Thereafter, the recording medium P is sent to the fixing device 37 by the transport device 36. The heating roller 37a of the fixing device 37 is controlled so as to be within a control range in which the third temperature is a target, and is in contact with the toner image on the recording medium to heat and pressurize the toner image. As a result, the toner image in which a plurality of colors are superimposed is fixed on the surface of the recording medium.
In this way, the recording medium on which the color image has been fixed is conveyed toward the paper discharge holding unit 39, and a series of image forming operations is completed. The image forming operation is terminated when, for example, the sensor 44 for detecting the recording medium on the downstream side of the fixing device 37 detects the passage of the trailing end of the recording medium. At this time, the photosensitive drum 21, the intermediate transfer belt 31, etc. Stop driving. Further, the control temperature of the heating roll 37a is changed from the third temperature to the second temperature.

  If the motor 28 that drives the rotary polygon mirror 27 of the exposure device 26 is stopped immediately after the end of the image forming operation or the temperature of the heating roll 37a of the fixing device 37 is lowered below the second temperature, the next image forming operation is performed. It will take time to start. For this reason, the rotary polygon mirror 27 is continuously driven even after the image forming operation is completed, and the temperature of the heating roll 37a is maintained within the control range targeting the second temperature. When a signal for performing the next image forming operation is input, the photosensitive drum 21 is activated without requiring a waiting time, and the image forming operation is started.

  When the predetermined time A1 has elapsed without the input of the signal for performing the next image forming operation after the image forming operation has been completed, the human detection sensor 40 has not detected the operator, The control temperature of the heating roll 37a is changed from the second temperature to the first temperature regardless of whether the person is in front of the image forming apparatus. Then, when a predetermined time B1 elapses from when the human detection sensor 40 no longer detects the operator, the driving of the rotary polygon mirror motor is stopped.

  On the other hand, when the operator approaches the image forming apparatus and operates any one of the document cover 16 and the like of the image reading apparatus 1 but does not input a signal to start the image forming operation as it is, for example, a start button is pressed. When not pressed, as shown in FIG. 3, the control temperature of the heating roll 37a is maintained at the second temperature, and the state in which the rotary polygon mirror 27 is driven is maintained until a predetermined time A1 elapses. When the predetermined time A1 has elapsed, as in the case after the image forming operation is performed, when the human detection sensor 40 does not detect the operator, the operator is in front of the image forming apparatus. In any case, the control temperature of the heating roll 37a is changed from the second temperature to the first temperature. Further, when the predetermined time B1 has elapsed since the human detection sensor 40 no longer detects the operator, the driving of the motor 28 of the rotary polygon mirror 27 is stopped.

  When this image forming apparatus functions as a printer or a facsimile, an image signal and a control signal attached thereto are input from an external device. When a signal indicating that image formation is to be performed in the image forming unit is input together with the image signal, as shown in FIG. 4, the control temperature of the heating roller 37a of the fixing device 37 that is in a standby state at the first temperature. Is changed from the first temperature to the second temperature. Further, the driving of the motor 28 of the rotary polygon mirror 27 is started with the change of the temperature. Then, when the temperature sensor 38 detects that the rotational speed of the rotary polygon mirror 27 is a speed at which laser light scanning is possible and the temperature of the heating roll 37a has reached the second temperature, the image forming operation is started. The At the same time, the control temperature of the heating roll 37a is changed from the second temperature to the third temperature.

  The image forming operation is performed in the same manner as when functioning as a copying machine. When the image forming operation is completed, the driving of the photosensitive drum 1, the intermediate transfer belt 31, and the like are stopped, and the control temperature of the heating roll 37a is changed from the third temperature to the second temperature. Then, when a predetermined time A1 has elapsed since the end of the image forming operation, the control temperature of the heating roll 37a of the fixing device 37 is changed from the second temperature to the first temperature, and the rotary polygon mirror 27 is changed. The driving of the motor 28 is stopped synchronously. Thereafter, as the temperature of the heating roll 37a gradually approaches the first temperature, the rotational speed of the rotary polygon mirror gradually decreases and stops and returns to the standby state.

Next, the operation of the image forming apparatus according to the embodiment of the present invention will be described.
This image forming apparatus has the configuration shown in FIG. 1. In this control, the heating control of the heating roll 37 a and the control of the motor 28 of the rotary polygon mirror 27 are performed using detection signals from the human detection sensor 40. This is different from the reference example described above in that the signal indicating that the image reading apparatus 1 is operated is not used.
In this image forming apparatus, as shown in FIG. 5, the human detection sensor 40 is in a standby state in which the temperature of the heating roll 37 a detected by the temperature sensor 38 is maintained within a control range targeting the first temperature. When a state where a person is approaching is detected, driving of the motor 28 of the rotary polygon mirror 27 is started. Then, when a predetermined time C elapses with the human detection sensor 40 detecting a state in which a person is approaching, the control temperature of the heating roll 37a is changed from the first temperature to the second temperature. The image forming operation is performed in a state where the rotational speed of the rotary polygon mirror 27 is a speed at which the laser beam can be scanned and the temperature of the heating roll 37a detected by the temperature sensor 38 is within the control range targeting the second temperature. The image forming operation is started when a signal to start the operation is input. The image forming operation is started before the rotational speed of the rotary polygon mirror 27 reaches a speed at which the laser beam can be scanned or before the temperature of the heating roll 37a detected by the temperature sensor 38 reaches the second temperature. When the signal is input, as in the reference example described above, the signal for starting the image forming operation is temporarily held, and the rotational speed of the rotary polygon mirror 27 is the speed at which the laser beam can be scanned. Thus, the image forming operation is started after the temperature of the heating roll 37a detected by the temperature sensor 38 reaches the second temperature. Further, the control temperature of the heating roll 37a is changed from the second temperature to the third temperature.
The image forming operation is performed in the same manner as the reference example described above.

  After the image forming operation is completed, the driving of the photosensitive drum 1, the intermediate transfer belt 31, and the like are stopped, and the control temperature of the heating roll 37a is changed from the third temperature to the second temperature. Until the predetermined time A2 elapses after the image forming operation is completed, the rotational speed of the rotary polygon mirror 27 is set to a speed at which the laser beam can be scanned, and the heating roll 37a detected by the temperature sensor 38. Is maintained within a control range that targets the second temperature, and when a signal to start the next image forming operation is input within this time, the next image forming operation is performed without waiting time. . If the human detection sensor 40 no longer detects the operator when the predetermined time A2 has passed without the input of the signal for starting the image forming operation, the control temperature of the heating roll 37a is set. Change from the second temperature to the first temperature. In this embodiment, if the human detection sensor 40 detects the operator before the image forming apparatus when a predetermined time A2 has elapsed, the control temperature of the heating roll 37a is set to the second temperature. The control temperature of the heating roll 37a is changed from the second temperature to the first temperature when the operator is no longer detected. When the human detection sensor 40 no longer detects the operator, whether this time is before or after the predetermined time A2 has elapsed, a predetermined time B2 from this time has elapsed. When the time has elapsed, the drive of the motor 28 of the rotary polygon mirror 27 is cut off, and the state returns to the standby state.

  On the other hand, as shown in FIG. 6, after a person approaches the image forming apparatus, the motor 28 of the rotary polygon mirror 27 is driven, and the control temperature of the heating roll 37a is changed to the second temperature, the image forming operation is performed. If a predetermined time A2 has passed without the input of the start signal, and the operator is not detected in front of the image forming apparatus, the control temperature of the heating roll 37a is changed from the second temperature to the second temperature. Change to 1 temperature. When the operator is detected before the image forming apparatus, the control temperature of the heating roll 37a is maintained at the second temperature, and when the operator is no longer detected, the control temperature of the heating roll is set to the second temperature. To the first temperature. Then, when a predetermined time B2 has elapsed from when the human detection sensor 40 no longer detects the operator, the driving of the motor 28 of the rotary polygon mirror 27 is stopped and the process returns to the standby state.

When this image forming apparatus functions as a printer or a facsimile, as in the above-described reference example, when a signal from an external apparatus is input, the image forming apparatus enters a standby state within a control range targeting the first temperature. The control temperature of the heating roller 37a of the fixing device 37 is changed from the first temperature to the second temperature, and the driving of the motor 28 of the rotary polygon mirror 27 is started simultaneously with this temperature change. When the predetermined time A2 has elapsed after the end of the image forming operation, the control temperature of the heating roll 37a of the fixing device 37 is changed from the second temperature to the first temperature, and the rotary polygon mirror 27 is changed. The driving of the motor 28 is stopped synchronously.

The image forming apparatus described above forms a color image using a plurality of colors of toner, and superimposes the toner image on the intermediate transfer belt. However, the image forming unit has other configurations. Various types of can be applied. Alternatively, a single color image may be formed. The toner image is fixed by heating, and the latent image can be formed with various configurations within the scope of the present invention as long as the rotating polygon mirror is used to scan the laser beam. be able to.
Further, the present invention is not limited to the above-described embodiments, and can be implemented as other forms within the scope of the present invention.

1: image reading unit, 2: image forming unit,
11: Exposure lamp, 12: Reflecting mirror, 13: Lens, 14: Image reading sensor, 15: Platen glass, 16: Document cover, 17: Document feeder
20: Image forming unit, 21: Photosensitive drum, 22: Charging device, 23: Developing device, 24: Primary transfer roll, 25: Cleaning device, 26: Exposure device, 27: Rotating polygon mirror (polygon mirror), 28: motor,
31: Intermediate transfer belt, 32: Driving roll, 33: Adjustment roll, 34: Opposing roll, 35: Secondary transfer roll, 36: Conveying device, 37: Fixing device, 37a: Heating roll, 37b: Pressure roll, 38 : Temperature sensor, 39: Paper discharge holding unit, 40: Human detection sensor, 41 conveying path, 42: Sheet storage unit, 43: Control device, 44: Sensor for detecting recording medium

Claims (4)

An image carrier on which a latent image is formed by a difference in electrostatic potential between an exposed portion and a non-exposed portion;
A rotating polygon mirror that is provided with a plurality of mirrors around and is rotated by a motor is irradiated with a flashing laser beam based on image information, and the laser beam reflected by the rotating polygon mirror is scanned on the image carrier. An exposure apparatus that performs exposure,
A developing device that transfers toner to a latent image on the image carrier formed by exposure by the exposure device and develops the toner;
A fixing device in which an image formed by adhesion of toner formed on the image holding member (hereinafter referred to as a toner image) is brought into contact with a recording medium transferred directly or via an intermediate transfer member, and is fixed by heating;
Heating means for heating a fixing member in contact with the recording medium of the fixing device;
A temperature sensor for detecting the temperature of the fixing member;
A human detection sensor for detecting an approaching person;
A control device that controls at least heating by the heating means and rotational driving of the motor;
The controller is
When the power supply is in an ON state, the heating sensor is controlled with a detection value of the temperature sensor as a target at a first temperature,
When the human detection sensor detects the approaching person, it starts driving the motor,
While the human detection sensor detects a state where a person is approaching, when a predetermined time C has elapsed, a target temperature for controlling the heating means is set to a second temperature higher than the first temperature. The image forming apparatus is characterized in that the temperature is changed to the temperature. The human detection sensor has a light emitting part and a light receiving part,
2. The image according to claim 1, wherein the light emitted from the light emitting unit is reflected by a person and detects a state in which the person is approaching due to a change in time until the light receiving unit receives the light. Forming equipment. After the image forming operation is started and the image forming operation is ended, or after the temperature targeted for the control is changed to the second temperature, a signal for starting the next image forming operation is input. When the predetermined time A2 has passed without the human detection sensor detecting a human, the control target temperature is changed to the first temperature, and the human detection sensor When the person detects a person, the control target temperature is maintained at the second temperature, and when a predetermined time B2 elapses after no person is detected, The image forming apparatus according to claim 2, wherein the driving is stopped. Wherein the person detecting sensor which includes a sound collector, and wherein the by sound or sound to continue repeating the middle of the collected sound is detected that the increase is to detect that the approaching person Item 2. The image forming apparatus according to Item 1 .

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