JP2011203679A - Image forming apparatus, image forming method and image formation control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus, an image forming method and an image formation control program capable of reducing resonant sound generated from respective devices such as a developing device or a charging device included in the image forming apparatus while handling changes in situation of the devices.SOLUTION: The image forming apparatus 1 includes: a photoreceptor 3 on a surface of which a latent image is formed; voltage control sections 31, 35 for outputting bias voltage by superposing DC voltage and AC voltage; a sound pressure detecting section 38 for detecting sound pressure generated in the image forming apparatus 1; a charging section 4 for charging the surface of the photoreceptor 3; an exposure section 5 for forming the latent image by exposing the surface of the photoreceptor 3 which is charged by the charging section 4; and a developing section 6 for forming a toner image by supplying toner to the latent image on the surface of the photoreceptor 3. In this case, voltage control sections 31, 35 output bias voltage of respectively different phases to a developing section 6 or the charging section 4 when the sound pressure in a prescribed frequency range detected by the sound pressure detecting section 38 is higher than a prescribed threshold.

Description

  The present invention relates to a technique for reducing resonance noise generated from each device such as a developing device and a charging device provided in an image forming apparatus.

  Conventionally, in an electrophotographic image forming apparatus such as a copying machine or a printer, as a power supply device for applying a driving voltage to a developing device or a charging device, a DC voltage obtained by rectifying an AC voltage and an AC generated by boosting are used. A power supply device that supplies a voltage superimposed with a voltage is used.

  However, when a driving voltage is applied to the developing device or the charging device by such a power supply device, each device vibrates in response to the voltage change of the AC voltage included in the driving voltage, and an unpleasant resonance sound is generated. There was a problem. Thus, for example, Patent Document 1 below describes a technique for reducing resonance noise by setting the AC voltage applied to neighboring devices in different phases.

JP 2003-66794 A

  However, in the technique described in Patent Document 1, since the phase of the AC voltage applied to neighboring devices is preset, there is a problem that it cannot cope with changes in the status of the device due to deterioration over time, fluctuations in outside air temperature, and the like. there were.

  Therefore, the present invention has been made in view of such circumstances, and has been designed to generate resonance noise generated from each device such as a developing device and a charging device provided in the image forming apparatus while responding to changes in the status of the device. An object of the present invention is to provide an image forming apparatus, an image forming method, and an image forming control program that can be reduced.

The invention according to claim 1 is a photoconductor on which a latent image is formed;
A voltage controller that outputs a bias voltage obtained by superimposing a DC voltage and an AC voltage;
A sound pressure detector that detects sound pressure generated in the image forming apparatus;
A charging unit for charging the surface of the photoreceptor;
An exposure unit that exposes the surface of the photoreceptor charged by the charging unit to form a latent image;
A developing unit for supplying toner to the latent image on the surface of the photoreceptor to form a toner image;
With
When the sound pressure in the predetermined frequency range detected by the sound pressure detection unit is higher than a predetermined threshold, the voltage control unit changes the phase of the bias voltage to each of the developing unit and the charging unit. An image forming apparatus for outputting.

Further, the invention described in claim 6 is generated in the image forming apparatus, a photoreceptor on which a latent image is formed, a voltage control unit that outputs a bias voltage obtained by superimposing a DC voltage and an AC voltage, and the image forming apparatus. A sound pressure detecting unit that detects a sound pressure to be applied; a charging unit that charges the surface of the photoconductor; an exposure unit that exposes the surface of the photoconductor charged by the charging unit to form a latent image; An image forming apparatus comprising: a developing unit that supplies toner to a latent image on a body surface to form a toner image;
An image forming method in which when the sound pressure in a predetermined frequency range detected by the sound pressure detection unit is higher than a predetermined threshold, the phase of the bias voltage is varied and output to the developing unit or the charging unit. is there.

Further, the invention described in claim 7 is generated in the image forming apparatus, a photoreceptor on which a latent image is formed, a voltage control unit that outputs a bias voltage obtained by superimposing a DC voltage and an AC voltage, and the image forming apparatus. A sound pressure detecting unit that detects a sound pressure to be applied; a charging unit that charges the surface of the photoconductor; an exposure unit that exposes the surface of the photoconductor charged by the charging unit to form a latent image; A computer built in an image forming apparatus comprising: a developing unit that supplies toner to a latent image on a body surface to form a toner image;
When the sound pressure in the predetermined frequency range detected by the sound pressure detection unit is higher than a predetermined threshold, the voltage control unit changes the phase of the bias voltage to each of the developing unit and the charging unit. An image formation control program that functions to output.

  When the developing unit or charging unit vibrates in response to a change in the bias voltage output to the developing unit or charging unit, a resonance sound is generated, and when the phase of the bias voltage is superimposed, Will be annoying noise.

  However, in these inventions, the voltage control unit outputs the bias voltage to the developing unit or the charging unit with different phases of the bias voltage based on the sound pressure actually detected in the image forming apparatus by the sound pressure detecting unit. be able to. For this reason, the sound pressure generated in the image forming apparatus can be reduced as compared with the case where the phase of the bias voltage output to the developing unit or the charging unit is superimposed while corresponding to the change in the sound pressure state in the image forming apparatus. Can be reduced.

The invention according to claim 2 is the image forming apparatus according to claim 1, further comprising an input operation unit for inputting an operation command by a user,
The input operation unit includes a combination of the developing unit and the charging unit to be subjected to different bias voltage phases, and a bias voltage phase between each of the developing unit and the charging unit included in the combination. In order to be different, it is configured to input a delay time when delaying the supply start timing of the bias voltage,
When the sound pressure in the predetermined frequency range detected by the sound pressure detection unit is higher than a predetermined threshold, the voltage control unit changes the phase of the bias voltage input via the input operation unit. Based on the combination of the developing unit and charging unit to be applied and the delay time corresponding to the combination, the phases of the bias voltages are made different from each other and output to the developing unit or the charging unit.

  In the present invention, via the input operation unit, the bias voltage phase is set between the combination of the developing unit and the charging unit to be biased and the developing unit and the charging unit included in the combination. In order to make them different, the delay time when delaying the supply start timing of the bias voltage can be flexibly adjusted according to the user's desire.

According to a third aspect of the present invention, there is provided the image forming apparatus according to the first or second aspect, wherein the combination of the developing unit and the charging unit to be subjected to different bias voltage phases is combined with the combination. A phase storage unit for storing a delay time when delaying the supply start timing of the bias voltage in order to make the phase of the bias voltage different between each of the developing unit and the charging unit included,
When the sound pressure in the predetermined frequency range detected by the sound pressure detection unit is higher than a predetermined threshold, the voltage control unit changes the phase of the bias voltage to each of the developing unit and the charging unit. The phase storage unit stores a combination of the developing unit and the charging unit when output, and a delay time obtained by delaying the supply start timing of the bias voltage between the developing unit and the charging unit, Thereafter, when the sound pressure in the predetermined frequency range detected by the sound pressure detecting unit is higher than a predetermined threshold, the developing unit stored in the phase storage unit and having different bias voltage phases. In addition, the phase of the bias voltage is varied based on the combination of the charging units and the delay time corresponding to the combination, and is output to the developing unit or the charging unit.

  In the present invention, the voltage control unit develops the bias voltage with different phases stored in the phase storage unit when the sound pressure in the predetermined frequency range detected by the sound pressure detection unit is higher than the predetermined threshold. Using the combination of the developing unit and the charging unit when output to the charging unit or the charging unit, and the delay time in which the bias voltage supply start timing is delayed between the developing unit and the charging unit, The phase of the bias voltage can be efficiently varied and output to the developing unit or the charging unit.

According to a fourth aspect of the present invention, the image forming apparatus according to the third aspect further includes an environment detection unit that detects the temperature or humidity of the image forming apparatus,
When the sound pressure in the predetermined frequency range detected by the sound pressure detection unit is higher than a predetermined threshold, the voltage control unit changes the phase of the bias voltage to each of the developing unit and the charging unit. The combination of the developing unit and the charging unit to be made different from each other in the temperature or humidity detected by the environment detection unit and the phase of the bias voltage when output, and the developing unit and the charging included in the combination In order to make the phase of the bias voltage different between each part, the phase storage unit stores the bias voltage supply start timing in combination with a delay time, and then the sound pressure detection unit The phase corresponding to the temperature or humidity detected by the environment detection unit when the sound pressure in the predetermined frequency range detected by the is higher than a predetermined threshold The developing unit by varying the phase of the bias voltage based on the delay time corresponding to the combination of the developing unit and the charging unit to be made different from each other and the phase of the bias voltage stored in the storage unit Or it outputs to the said charging part.

  According to the present invention, the sound pressure detection unit according to the change in the temperature or humidity of the image forming apparatus is different in how the sound generated in the image forming apparatus is transmitted according to the change in the temperature or humidity of the image forming apparatus. Even when the sound pressure in the predetermined frequency range detected by the change is detected, the phase of the bias voltage stored in the phase storage unit corresponding to the temperature or humidity detected by the environment detection unit is made different. Based on the combination of the developing unit and the charging unit and the delay time corresponding to the combination, it is possible to efficiently output the bias voltage to the developing unit or the charging unit with different phases.

The invention according to claim 5 is the image forming apparatus according to any one of claims 1 to 4, further comprising a warning output unit for outputting a warning sound,
The sound pressure detection unit is also used as the warning output unit.

  In this invention, since the sound pressure detection unit is also used as a warning output unit that outputs a warning sound, for example, the image forming apparatus according to the present invention can be configured at low cost without newly providing a piezoelectric element or the like. become.

  According to the present invention, an image forming apparatus, an image forming method, and an image forming method capable of reducing resonance noise generated from each device such as a developing device and a charging device provided in the image forming device while responding to a change in the state of the device. An image formation control program can be provided.

1 is a schematic sectional view of a printer. FIG. 2 is a functional block diagram illustrating an electrical configuration of a printer. The circuit block diagram of a sound pressure detection part. Schematic explanatory drawing which shows the principal part structure of a voltage control part. FIG. 6 is a diagram illustrating an example of a bias voltage waveform supplied to a developing unit. It is a figure which shows an example of the bias voltage waveform output to the image development part by each voltage control part, (a) shows the bias voltage waveform when not adjusting the phase of the bias voltage output to the image development part of each color , (B) shows the bias voltage waveform when the phase of the bias voltage output to the developing section of each color is adjusted. 6 is a flowchart showing a flow of an image forming operation. The circuit block diagram of a warning output part.

  The image forming apparatus according to the present invention will be described below with reference to the drawings. In this embodiment, a printer is described as an example of an image forming apparatus. However, the present invention is not limited to this, and a copier, a facsimile machine, or a multifunction machine having various functions may be used in addition to the printer.

  FIG. 1 is a schematic sectional view of a printer 1 according to the present embodiment. As shown in FIG. 1, the printer 1 includes image forming units 2Y, 2M, 2C, and 2K (hereinafter referred to as “yellow” (Y), magenta (M), cyan (C), and black (K)). The image forming unit 2 is collectively provided.

  The image forming unit 2 forms (prints) a color image on a sheet. For example, the photosensitive drum 3, a charging unit 4 disposed around the photosensitive drum 3, an exposure unit 5, and a developing unit 6. (Developing units 6Y, 6M, 6C and 6K) and a photoconductor cleaning unit 7 are provided.

  The charging unit 4 applies a bias voltage to a charging roller (not shown) disposed around the photosensitive drum 3 to uniformly charge the surface of the photosensitive drum 3 to a predetermined potential. The bias voltage applied to the charging roller is supplied by a power supply device 35 described later.

  The exposure unit 5 irradiates the photosensitive drum 3 with light generated based on image data stored in an image memory 32 described later, and forms an electrostatic latent image on the surface of the photosensitive drum 3. .

  The developing unit 6 supplies toner from a cartridge 61 to a developing roller (not shown), applies a bias voltage to the developing roller, and generates a potential difference between the photosensitive drum 3 and the developing roller, thereby causing a photosensitive drum. The toner is attached to the electrostatic latent image formed on the photosensitive drum 3 to be manifested as a toner image on the photosensitive drum 3. The bias voltage applied to the developing roller is supplied by a power supply device 35 described later.

  The photosensitive member cleaning unit 7 removes toner adhering to the surface of the photosensitive drum 3 after primary transfer of a toner image to an intermediate transfer belt 10 described later.

  The cartridge 61 stores toners for yellow, magenta, cyan, and black corresponding to each developing unit 6 and is configured to be detachable from the apparatus main body. When the amount of toner in the cartridge 61 decreases, the toner is replenished in the apparatus main body by replacing with a new cartridge.

  Below the image forming unit 2, a primary transfer roller 9 and an intermediate transfer belt 10 are provided for performing intermediate transfer of a toner image that has become apparent on the surface of the photosensitive drum 3.

  The intermediate transfer belt 10 is formed of a predetermined belt body and is configured to rotate endlessly by driving rollers 11 to 13 while being pressed against the photosensitive drum 3 by a primary transfer roller 9 disposed to face each photosensitive drum 3. Has been. The toner images of the respective colors formed on the photosensitive drum 3 are transferred and superposed on the intermediate transfer belt 10 that is rotated endlessly in order of yellow, magenta, cyan, and black. As a result, a color image having four colors is formed on the intermediate transfer belt 10.

  A cleaning unit 18 that removes toner (residual toner) on the intermediate transfer belt 10 is provided at a position facing the driving roller 12. A secondary transfer roller 14 for transferring a color image on the intermediate transfer belt 10 to a sheet is provided at a position facing the drive roller 13.

The printer 1 also includes a paper feeding unit 15 that feeds paper toward the image forming unit 2. The paper feed unit 15 includes a paper feed cassette 151 that stores paper, a transport path 152 that is a path through which the paper is transported, a transport roller 153 that transports the paper in the transport path 152, and the like. The sheets taken out one by one are conveyed toward the image forming unit 2, that is, the position of the secondary transfer roller 14. Further, the paper feeding unit 15 conveys the paper subjected to the secondary transfer process to the fixing unit 16 and discharges the paper subjected to the fixing process to a discharge tray 17 at the upper part of the printer main body.

  The fixing unit 16 is provided at an appropriate position on the downstream side of the secondary transfer roller 14 in the conveyance path 152 and fixes the toner image transferred onto the sheet. The fixing unit 16 includes a pressure roller 161 and a heating roller 162. The toner on the paper is melted by the heat of the heating roller 162, and pressure is applied by the pressure roller 161 to fix the toner on the paper.

  FIG. 2 is a functional block diagram showing the electrical configuration of the printer 1. The printer 1 includes a control unit 31, an image memory 32, a storage unit 33, a paper feeding unit 15, an image processing unit 34, an image forming unit 2, a power supply device 35, an input operation unit 36, a network I / F unit 37, and sound pressure detection. A portion 38 is provided. In addition, the same code | symbol is attached | subjected to the same component as demonstrated in FIG. 1, and detailed description is abbreviate | omitted.

  The control unit 31 is configured by a CPU (Central Processing Unit) or the like, and executes processing based on a predetermined program according to an input instruction signal or the like, and outputs an instruction signal to each functional unit, data transfer, or the like. The printer 1 is controlled in an integrated manner.

  The image memory 32 is configured by a recording medium such as a RAM or a hard disk, and temporarily stores image data transmitted from an unillustrated external device (such as a personal computer) via the network I / F unit 37.

  The storage unit 33 is configured by a memory such as a ROM or a RAM, and data used in programs and control programs for realizing various functions of the printer 1 such as an image formation control program according to an embodiment of the present invention. Is temporarily stored.

  The image processing unit 34 performs image processing such as image correction and enlargement / reduction on the image data input via the network I / F unit 37.

  The power supply device 35 supplies a bias voltage to the developing unit 6 and the charging unit 4 of the image forming unit 2. Specifically, the control signal for each color of yellow (Y), magenta (M), cyan (C), and black (K) based on the image data subjected to image processing by the image processing unit 34 by the control unit 31. Is generated and output to the image forming unit 2 and the power supply device 35. In accordance with the control signals for the respective colors, the exposure unit 5 of the image forming unit 2 irradiates the surface of the photosensitive drum 3 with light, and the power supply device 35 supplies a bias voltage to the developing unit 6 and the charging unit 4.

  The input operation unit 36 inputs an operation command from the user. Specifically, the input operation unit 36 includes a power key, a start button, a setting key for setting various functions, and a display panel for displaying various messages. When the user performs an operation, the operation signal is transmitted to the control unit. To 31.

  The network I / F unit 37 includes a communication module such as a LAN board, and transmits / receives various data to / from an external device via a network (not shown) connected to the network I / F unit 37.

  The sound pressure detection unit 38 includes a piezoelectric element that detects sound pressure and outputs an electric signal (detection signal) indicating the detected sound pressure, such as a piezoelectric element or a condenser microphone, and outputs a detection signal of the piezoelectric element. By performing predetermined signal processing, an electrical signal corresponding to a sound pressure in a predetermined frequency range generated by the printer 1 is output to the control unit 31.

  For example, as shown in FIG. 3, the sound pressure detector 38 includes a power supply E1, a piezoelectric element 381, an amplifier 382, capacitors C1, C2, C3, C4, resistors R1, R2, diodes D1, D2, and an A / D converter. 383 is provided.

  The detection signal output from the piezoelectric element 381 has its DC component cut by the capacitor C1, amplified by the amplifier 382 via the resistor R1, integrated by the resistor R2 and the capacitor C2, and further removed noise including high frequency components. Is done. Next, the DC component is cut by the capacitor C3, rectified by the diodes D1 and D2, and smoothed by the capacitor C4 to be converted into a DC signal. The DC signal is converted into a digital signal by the A / D converter 383 and output to the control unit 31.

  The sound indicated by the electrical signal output from the sound pressure detection unit 38 to the control unit 31 by changing the set values such as the capacitances of the capacitors C1, C2, C3, and C4 and the resistance values of the resistors R1 and R2. The frequency range of the pressure can be adjusted. In the present embodiment, the set values of the respective elements are set in advance so that an electrical signal corresponding to the sound pressure in the audible region is output. However, the purpose is not limited to this. In addition, the circuit configuration of the sound pressure detection unit 38 illustrated in FIG. 3 is merely an example, and is not intended to be limited thereto.

  Next, the power supply device 35 will be described in detail. For example, as illustrated in FIG. 4, the power supply device 35 is provided for each developing unit 6 of each color of yellow (Y), magenta (M), cyan (C), and black (K) of the image forming unit 2, that is, a bias. For each voltage supply destination, a DC voltage control circuit 354 (354 Y, 354 M, 354 C, 354 K in the figure), an AC voltage control circuit 353 (353 Y, 353 M, 353 C, 353 K in the figure), and a DC power supply 351 (FIG. 351Y, 351M, 351C, 351K) and an AC power supply 352 (352Y, 352M, 352C, 352K in the figure).

  When a control signal is input from the control unit 31, the DC voltage control circuit 354 outputs a control signal indicating various parameters such as a voltage level of a DC voltage to be applied to the developing unit 6 based on the control signal. To do.

  When a control signal is input from the control unit 31, the AC voltage control circuit 353 generates control signals indicating various parameters such as the frequency and phase of the AC voltage to be applied to the developing unit 6 based on the control signal. Output.

  The DC power supply 351 receives a control signal output from the DC voltage control circuit 354, inputs an AC voltage supplied from an AC power supply such as a commercial power supply to a transformer (not shown), and is determined by the control signal. The voltage is transformed to a predetermined voltage level, and the transformed AC voltage is converted to a DC voltage by a rectifier circuit (not shown).

  The AC power source 352 receives the control signal output from the AC voltage control circuit 353, and converts the AC voltage supplied from the AC power source such as a commercial power source into an AC voltage having a frequency and phase determined by the control signal. The voltage is converted, the AC voltage is superimposed on the DC voltage input from the DC power supply 351, and a bias voltage in which the DC voltage and the AC voltage are superimposed is output to the developing unit 6.

  For example, as shown in FIG. 5, the DC power supply 351 converts an AC voltage supplied from an AC power supply such as a commercial power supply into a DC voltage of 200 V based on the control signal output from the DC voltage control circuit 354. The AC power supply 352 outputs an AC voltage supplied from an AC power supply such as a commercial power supply with a frequency of 4 KHz, a duty of 30%, and a peak voltage of 1.6 kV based on the control signal of the AC voltage control circuit 353. The bias voltage is converted to an AC voltage, and a bias voltage obtained by superimposing the AC voltage and the DC voltage of 200 V output from the DC voltage control circuit 354 is output to the developing unit 6.

  Various parameters such as the bias voltage frequency, duty, peak voltage, and shift amount for shifting the AC voltage waveform (voltage level of the superimposed DC voltage) are appropriately controlled according to the conditions at the time of image formation.

  Further, when the sound pressure in the predetermined frequency range detected by the sound pressure detection unit 38 is higher than a predetermined threshold, the control unit 31 outputs the bias voltage with different phases to the developing unit 6. It is configured.

  The predetermined threshold is determined in advance based on, for example, an experimental value such as a test operation of the printer 1 and stored in the storage unit 33. However, the predetermined threshold is not limited to this, and may be input by the user via the input operation unit 36.

  Specifically, for example, FIG. 6A shows that the power supply device 35 has a duty of 70% with respect to the developing unit 6 of each color of yellow (Y), magenta (M), cyan (C), and black (K). The voltage waveform of the bias voltage supplied to the developing unit 6 of each color when the bias voltage is output is shown. In this case, the phases of the bias voltages of yellow (Y) and cyan (C) are overlapped. Therefore, the yellow (Y) and cyan (C) developing units 6 are vibrated as the bias voltage changes. Resonant sound that is superimposed is also superimposed, and harsh noise is generated.

  Here, when the control unit 31 determines that the resonance sound becomes loud, that is, the sound pressure in the predetermined frequency range indicated by the output signal of the sound pressure detection unit 38 is higher than a predetermined threshold, for example, FIG. As shown in (b), the control signal is set so that the phases of the bias voltages supplied to the developing units 6 for the respective colors of yellow (Y), magenta (M), cyan (C), and black (K) are different. Is input to the AC voltage control circuit 353 for each color.

  Specifically, the control unit 31 uses an edge waveform Wy indicating the supply start timing of the yellow (Y) bias voltage and an edge waveform Wc indicating the supply start timing of the cyan (C) bias voltage for a predetermined delay time. By transmitting the control signal to the cyan (C) AC voltage control circuit 353 when the delay time Tyc elapses after transmitting the control signal to the yellow (Y) AC voltage control circuit 353 in order to shift Tyc, The phases of the bias voltages supplied to the developing units 6 for yellow (Y) and cyan (C) are made different from each other.

  Here, the predetermined delay time is determined in advance based on, for example, an experimental value such as a test operation of the printer 1, and is stored in the storage unit 33 in combination with a combination of colors to be subjected to different bias voltage phases. It is remembered. In the example shown in FIG. 6B, the combination of yellow (Y) and cyan (C) and the delay time Tyc are stored in the storage unit 33 in a combined form.

  The delay time Tyck (not shown) is not limited to this, so that the phases of the bias voltages supplied to the developing units 6 for the respective colors of yellow (Y), cyan (C), and black (K) are different. (Y), cyan (C), and black (K) may be combined and stored in the storage unit 33. That is, it is not intended to limit the combinations of colors to be subjected to different bias voltage phases and the delay times corresponding to the combinations to the above example.

  Next, the AC voltage control circuit 353 for each color generates a control signal indicating various parameters of the AC voltage to be applied to the developing unit 6 based on the control signal input from the control unit 31. The AC power source 352 for each color outputs bias voltages having different phases to the developing unit 6 based on the control signal input from the AC voltage control circuit 353 for each color.

  That is, the control unit 31 and the power supply device 35 constitute an example of the voltage control unit in the present invention.

  Hereinafter, the flow of the image forming operation in the above configuration will be described.

  As shown in FIG. 7, when a control signal based on image data to be formed is input from the control unit 31 to the power supply device 35, the power supply device 35 applies a DC voltage control to a predetermined bias voltage determined by the control signal. Output to the developing unit 6 via the circuit 354 and the AC voltage control circuit 353 (S1).

  When the control signal is input from the control unit 31 to the power supply device 35, that is, when the image forming operation is not completed (S2; NO), the sound pressure detection unit 38 detects the sound pressure generated in the printer 1. Then, an electric signal indicating the detected sound pressure is output to the control unit 31 (S3).

  When the control unit 31 determines that the sound pressure indicated by the electrical signal of the sound pressure detection unit 38 is higher than the predetermined threshold (S4; YES), the control unit 31 adjusts the bias voltage phases of the respective colors to be different as described above. A control signal is output to the power supply device 35 (S5), and the process of step S1 is executed.

  When the sound pressure indicated by the electrical signal from the sound pressure detection unit 38 is determined to be equal to or lower than the predetermined threshold (S4; NO), the control unit 31 does not adjust the phase of the bias voltage of each color to be different from each other. Then, a predetermined control signal is output to the power supply device 35, and the process of step S1 is executed.

  When the image formation is completed (S2; YES), the control unit 31 ends the input of the control signal to the power supply device 35 and ends the image formation process.

  That is, when the developing unit 6 vibrates in response to a change in the bias voltage output to the developing unit 6, a resonance sound is generated, and when the phase of the bias voltage is superimposed, the resonance sound overlaps. However, in the configuration of the present embodiment, the control unit 31 and the power supply device 35 (voltage control unit) are based on the sound pressure actually detected in the printer 1 by the sound pressure detection unit 38. The phase of the bias voltage can be made different and output to the developing unit 6.

  For this reason, the sound pressure generated in the printer 1 can be reduced as compared with the case where the phase of the bias voltage output to the developing unit 6 is superimposed while corresponding to the change in the sound pressure status in the printer 1. become able to.

  In the above description, when the sound pressure in the predetermined frequency range detected by the sound pressure detecting unit 38 is higher than the predetermined threshold, the voltage control unit outputs bias voltages having different phases to the developing units 6 of the respective colors. The DC voltage control circuit for supplying a bias voltage to the charging unit 4 of each color of yellow (Y), magenta (M), cyan (C), and black (K) is described. 354, an AC voltage control circuit 353, a DC power source 351, and an AC power source 352 are configured, and the voltage control unit has a predetermined frequency range detected by the sound pressure detection unit 38 as described above. When the sound pressure is higher than a predetermined threshold value, bias voltages having different phases may be supplied to the charging roller of the charging unit 4 of each color.

  Alternatively, by combining them, the voltage control unit applies the bias voltages having different phases when the sound pressure in the predetermined frequency range detected by the sound pressure detection unit 38 is higher than the predetermined threshold value. In addition, the charging unit 4 may be supplied.

  In addition to the above-described configuration, the input operation unit 36 includes a combination of the developing unit 6 and the charging unit 4 to be subjected to different bias voltage phases, and each unit of the developing unit 6 and the charging unit 4 included in the combination. In order to make the phases of the bias voltages different from each other, a delay time when delaying the supply start timing of the bias voltage is input, and the voltage control unit is configured to input a predetermined time detected by the sound pressure detection unit 38. When the sound pressure in the frequency range is higher than a predetermined threshold, the combination of the developing unit 6 and the charging unit 4 that are input via the input operation unit 36 and whose bias voltage phases are different from each other corresponds to the combination. Based on the above delay time, the phase of the bias voltage may be varied and output to the developing unit 6 or the charging unit 4.

  Here, the combination of the developing unit 6 and the charging unit 4 to be subjected to different bias voltage phases is, for example, a combination of yellow (Y) and cyan (C) in the example shown in FIG. 6B. The delay time when delaying the supply start timing of the bias voltage so as to make the phase of the bias voltage different between the respective parts of the developing unit 6 and the charging unit 4 included in the combination is the bias of cyan (C) This is a delay time Tyc when the edge waveform Wc indicating the voltage supply start timing is delayed from the edge waveform Wy indicating the yellow (Y) bias voltage supply start timing.

  That is, in order to make the phase of the bias voltage different between the combination of the developing unit 6 and the charging unit 4 to be made different in the phase of the bias voltage, and each part of the developing unit 6 and the charging unit 4 included in the combination, The phase relationship of the bias voltage in the developing unit 6 or the charging unit 4 is shown by the delay time when the supply start timing of the bias voltage is delayed.

  In the present configuration, for example, the control unit 31 performs the development unit when the sound pressure in the predetermined frequency range detected by the sound pressure detection unit 38 is higher than a predetermined threshold in step S4 (FIG. 7). 6 or a display screen for performing an input operation on the phase relationship of the bias voltage in the charging unit 4 is displayed on the display panel. In step S5 (FIG. 7), the display screen is displayed via the input operation unit 36 by the user. In accordance with the phase relationship of the bias voltage input to, a control signal to be output to the developing unit 6 or the charging unit 4 is output by changing the phase of the bias voltage.

  According to this configuration, the combination of the developing unit 6 and the charging unit 4 to be made different in phase of the bias voltage via the input operation unit 36, and between the units of the developing unit 6 and the charging unit 4 included in the combination. Thus, in order to make the phases of the bias voltages different from each other, the delay time when delaying the supply start timing of the bias voltage can be flexibly adjusted according to the desire of the user.

  In addition to the above configuration, as shown by the broken line portion in FIG. 2, the combination of the developing unit 6 and the charging unit 4 to be subjected to different bias voltage phases, and the developing unit 6 and the charging unit included in the combination. A phase storage unit 331 for storing a delay time when delaying the supply start timing of the bias voltage may be further provided so that the phase of the bias voltage differs between the units of the unit 4.

  Accordingly, when the sound pressure in the predetermined frequency range detected by the sound pressure detecting unit 38 is higher than a predetermined threshold, the voltage control unit changes the bias voltage phase to change the developing unit 6 or the charging unit. The phase of the combination of the developing unit 6 and the charging unit 4 and the delay time in which the bias voltage supply start timing is delayed between the developing unit 6 and the charging unit 4 when output to the unit 4 When the sound pressure in the predetermined frequency range that is stored in the storage unit 331 and then detected by the sound pressure detection unit 38 is higher than the predetermined threshold, the phase of the bias voltage stored in the phase storage unit 331 is Based on the combination of the developing unit 6 and the charging unit 4 to be differentiated and the delay time corresponding to the combination, the phases of the bias voltages are varied and output to the developing unit 6 or the charging unit 4. Sea urchin may be configured.

  In the present configuration, in step S5 (FIG. 7), when the control unit 31 outputs a control signal that varies the phase of the bias voltage supplied to the developing unit 6 or the charging unit 4 of each color, Phase relationship of bias voltage in the developing unit 6 or the charging unit 4 (the bias voltage supply start timing is delayed between the combination of the developing unit 6 and the charging unit 4 and each unit of the developing unit 6 and the charging unit 4) The delay time) can be stored in the phase storage unit 331.

  Further, the controller 31 stores the phase relationship of the bias voltage from the phase storage unit 331 in step S1 (FIG. 7) after storing the phase relationship of the bias voltage in the developing unit 6 or the charging unit 4 of each color in the phase storage unit 331. The relationship is acquired, and a control signal for making the phase of the bias voltage different from each other based on the phase relationship of the acquired bias voltage is output to the power supply device 35. The power supply device 35 has a predetermined bias determined by the control signal. The voltage can be output to the developing unit 6 via the DC voltage control circuit 354 and the AC voltage control circuit 353.

  According to this configuration, the sound pressure in the predetermined frequency range is not necessarily equal to or lower than the threshold value depending on changes in the temperature and humidity of the image forming apparatus, but the bias voltage stored in the phase storage unit 331 in advance. Since bias voltages having different phases are supplied to the developing unit 6 based on the phase relationship, the sound pressure in the predetermined frequency range detected by the sound pressure detecting unit 38 in step S4 during the image forming operation is greater than or equal to the threshold value. The possibility of becoming is reduced. For this reason, the opportunity to perform the process of step S5 is reduced, and the phase of the bias voltage can be made different from each other and output to the developing unit 6 or the charging unit 4 efficiently.

  Further, in addition to this configuration, an environment detection unit that detects the temperature or humidity of the printer 1 is further provided, and the voltage control unit detects that the sound pressure in the predetermined frequency range detected by the sound pressure detection unit 38 is greater than a predetermined threshold. In the case where the phase of the bias voltage is different and the temperature or humidity detected by the environment detection unit when the bias voltage is output to the developing unit 6 or the charging unit 4 and the phase of the bias voltage is different. The delay time when delaying the supply start timing of the bias voltage so that the phase of the bias voltage differs between the combination of the unit 6 and the charging unit 4 and the developing unit 6 and the charging unit 4 included in the combination. Is stored in the phase storage unit 331, and then the environment detection is performed when the sound pressure in the predetermined frequency range detected by the sound pressure detection unit 38 is higher than a predetermined threshold. The combination of the developing unit 6 and the charging unit 4 to be made different from each other in the phase of the bias voltage stored in the phase storage unit 331 corresponding to the temperature or humidity detected by the unit, and the delay time corresponding to the combination. Based on this, the phase of the bias voltage may be varied and output to the developing unit 6 or the charging unit 4.

  In this configuration, for example, as shown by a broken line portion in FIG. 2, the environment detection unit 30 provides a sensor for detecting the temperature or humidity around the developing unit 6 or the charging unit 4, and detection output from the sensor. The signal may be output to the control unit 31.

  In accordance with this, when the control unit 31 outputs a control signal that varies the phase of the bias voltage supplied to the developing unit 6 or the charging unit 4 of each color in step S5 (FIG. 7), the environment detection is performed. The phase relationship between the temperature or humidity indicated by the detection signal of the unit 30 and the bias voltage in the developing unit 6 or the charging unit 4 of each color (the combination of the developing unit 6 and the charging unit 4, the developing unit 6 and the charging unit) 4 can be configured to be stored in the phase storage unit 331 in combination with a delay time when delaying the supply start timing of the bias voltage.

  Further, the control unit 31 stores the temperature or humidity indicated by the detection signal of the environment detection unit 30 and the phase relationship of the bias voltage in the developing unit 6 or the charging unit 4 of each color in the phase storage unit 331 in combination. In step S1 (FIG. 7), the phase relationship of the bias voltage corresponding to the temperature or humidity indicated by the detection signal of the environment detection unit 30 is acquired from the phase storage unit 331, and based on the acquired phase relationship of the bias voltage. A control signal for making the phase of the bias voltage different can be output to the power supply device 35.

  The way in which sound is transmitted differs depending on the change in the temperature or humidity of the printer 1. In the present invention, however, the predetermined frequency range detected by the sound pressure detection unit 38 in accordance with the change in the temperature or humidity of the printer 1. Even when the sound pressure changes, the developing unit 6 and the charging unit 6 are charged with different phases of the bias voltage stored in the phase storage unit 331 corresponding to the temperature or humidity detected by the environment detection unit 30. Based on the combination of the units 4 and the delay time corresponding to the combination, the bias voltage phases can be efficiently varied and output to the developing unit 6 or the charging unit 4.

  In addition to the above configuration, a warning output unit that outputs a warning sound may be provided, and the sound pressure detection unit 38 may also be configured to be used as the warning output unit.

  For example, as shown in FIG. 8, the warning output unit 39 includes a speaker unit 392 that generates a warning sound and a transistor 391 that drives the speaker unit 392 based on a control signal from the control unit 31 described later. When the controller 31 detects the occurrence of an error based on various detection signals, such as an unillustrated double feed detection sensor that detects that a plurality of sheets are conveyed in a superimposed manner, the control unit 31 indicates a warning sound generation instruction. The control signal is output to the warning output unit 39.

  Here, the speaker unit 392 is configured to generate a warning sound by vibrating the speaker in accordance with the electric signal. On the contrary, when the electric signal is not input, the speaker unit 392 corresponds to the vibration of the speaker. An electrical signal is generated. Therefore, the speaker unit 392 can also be used as the piezoelectric element 381 provided in the sound pressure detecting unit 38 as having the same function as the piezoelectric element 381 provided in the sound pressure detecting unit 38 shown in FIG.

  According to this configuration, for example, when an error such as a paper jam occurs during an image forming operation, the warning output unit that outputs a warning sound to inform the operator of the error occurrence state is generally an image. Since it is provided in the forming apparatus, the sound pressure detection unit of the present invention can be configured at low cost without newly providing a piezoelectric element or the like.

  In the above embodiment, as an example of the image forming apparatus according to the present invention, a color printer capable of forming an image with each color of yellow (Y), magenta (M), cyan (C), and black (K) is shown. The image forming apparatus according to the invention may be a monochrome printer. In this case, the voltage control unit makes the phase of the bias voltage output to the developing unit 6 different from the phase of the bias voltage output to the charging unit 4. The resonance noise generated in the developing unit 6 and the charging unit 4 can be reduced.

  In the above embodiment, the configurations and settings shown in FIGS. 1 to 8 are merely examples, and the present invention is not limited to the embodiment.

1 Printer (image forming device)
3 Photosensitive drum (photosensitive member)
4 Charging unit 5 Exposure unit 6 Development unit 30 Environment detection unit 31 Control unit (voltage control unit)
35 Power supply (voltage control unit)
36 Input operation unit 38 Sound pressure detection unit 39 Warning output unit 331 Phase storage unit

Claims (7)

A photoreceptor on which a latent image is formed;
A voltage controller that outputs a bias voltage obtained by superimposing a DC voltage and an AC voltage;
A sound pressure detector that detects sound pressure generated in the image forming apparatus;
A charging unit for charging the surface of the photoreceptor;
An exposure unit that exposes the surface of the photoreceptor charged by the charging unit to form a latent image;
A developing unit for supplying toner to the latent image on the surface of the photoreceptor to form a toner image;
With
When the sound pressure in the predetermined frequency range detected by the sound pressure detection unit is higher than a predetermined threshold, the voltage control unit changes the phase of the bias voltage to each of the developing unit and the charging unit. An image forming apparatus for outputting. An input operation unit for inputting an operation command by the user is further provided,
The input operation unit includes a combination of the developing unit and the charging unit to be subjected to different bias voltage phases, and a bias voltage phase between each of the developing unit and the charging unit included in the combination. In order to be different, it is configured to input a delay time when delaying the supply start timing of the bias voltage,
When the sound pressure in the predetermined frequency range detected by the sound pressure detection unit is higher than a predetermined threshold, the voltage control unit changes the phase of the bias voltage input via the input operation unit. The output from the developing unit or the charging unit with different phases of the bias voltage based on a combination of the developing unit and the charging unit to be applied and the delay time corresponding to the combination. Image forming apparatus. In order to make the phase of the bias voltage different between the combination of the developing unit and the charging unit to be made different from each other in the phase of the bias voltage, and each part of the developing unit and the charging unit included in the combination, A phase storage unit that stores a delay time when delaying the supply start time of
When the sound pressure in the predetermined frequency range detected by the sound pressure detection unit is higher than a predetermined threshold, the voltage control unit changes the phase of the bias voltage to each of the developing unit and the charging unit. The phase storage unit stores a combination of the developing unit and the charging unit when output, and a delay time obtained by delaying the supply start timing of the bias voltage between the developing unit and the charging unit, Thereafter, when the sound pressure in the predetermined frequency range detected by the sound pressure detecting unit is higher than a predetermined threshold, the developing unit stored in the phase storage unit and having different bias voltage phases. And a phase of the bias voltage is varied based on the combination of the charging units and the delay time corresponding to the combination and output to the developing unit or the charging unit. The image forming apparatus according to 2. An environment detection unit for detecting the temperature or humidity of the image forming apparatus;
When the sound pressure in the predetermined frequency range detected by the sound pressure detection unit is higher than a predetermined threshold, the voltage control unit changes the phase of the bias voltage to each of the developing unit and the charging unit. The combination of the developing unit and the charging unit to be made different from each other in the temperature or humidity detected by the environment detection unit and the phase of the bias voltage when output, and the developing unit and the charging included in the combination In order to make the phase of the bias voltage different between each part, the phase storage unit stores the bias voltage supply start timing in combination with a delay time, and then the sound pressure detection unit The phase corresponding to the temperature or humidity detected by the environment detection unit when the sound pressure in the predetermined frequency range detected by the is higher than a predetermined threshold The developing unit by varying the phase of the bias voltage based on the delay time corresponding to the combination of the developing unit and the charging unit to be made different from each other and the phase of the bias voltage stored in the storage unit The image forming apparatus according to claim 3, wherein the image forming apparatus outputs data to the charging unit. It further includes a warning output unit that outputs a warning sound,
The image forming apparatus according to claim 1, wherein the sound pressure detection unit is also used as the warning output unit. A photoreceptor on which a latent image is formed, a voltage control unit that outputs a bias voltage obtained by superimposing a DC voltage and an AC voltage, and a sound pressure detection unit that detects a sound pressure generated in the image forming apparatus. A charging unit for charging the surface of the photoconductor, an exposure unit for exposing the surface of the photoconductor charged by the charging unit to form a latent image, and supplying toner to the latent image on the surface of the photoconductor An image forming apparatus comprising: a developing unit that forms a toner image;
An image forming method in which, when a sound pressure in a predetermined frequency range detected by the sound pressure detection unit is higher than a predetermined threshold, the bias voltage is made different in phase and output to the developing unit or the charging unit. A photoreceptor on which a latent image is formed, a voltage control unit that outputs a bias voltage obtained by superimposing a DC voltage and an AC voltage, and a sound pressure detection unit that detects a sound pressure generated in the image forming apparatus. A charging unit for charging the surface of the photoconductor, an exposure unit for exposing the surface of the photoconductor charged by the charging unit to form a latent image, and supplying toner to the latent image on the surface of the photoconductor A computer built in an image forming apparatus comprising: a developing unit that forms a toner image;
When the sound pressure in the predetermined frequency range detected by the sound pressure detection unit is higher than a predetermined threshold, the voltage control unit changes the phase of the bias voltage to each of the developing unit and the charging unit. An image formation control program that functions to output.

Images