JP2005134413A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus surely cleaning excessive toner by varying transferring and attracting voltage at the time when transfer paper is passed by a transfer means and at other times and also stably carrying the transfer paper. <P>SOLUTION: When detected temperature and humidity inside and outside of an apparatus by an apparatus interior temperature sensor 34 and an apparatus exterior temperature sensor 35 are fed to environmental compensation table storing memory 27, whether the apparatus is in a state of having the transfer paper passed or in any other state is judged. In the time of transfer paper passing, the temperature and the humidity of the outside of the apparatus are used to select a compensating value in the environmental compensation table and output to an operation part 28, and in the time of other than transfer paper passing such as paper interval the temperature and the humidity of the inside of the apparatus are used to select the compensating value in the environmental compensation table and output to the operation part 28. A reference current value or reference voltage value is compensated in the operation part 28 by using the selected compensation values. The transfer voltage and the attracting voltage are controlled by outputting the best current value or voltage value to a transfer roller 4 or an attracting roller 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus using electrophotography.

  An image forming process of a conventional image forming apparatus will be described with reference to FIG. FIG. 5 is a schematic diagram showing the configuration of the color image forming apparatus. In the color image forming apparatus main body, four image forming portions Pa, Pb, Pc and Pd are located upstream of the conveying belt 8 (right side in FIG. 5). Are arranged in order. These image forming portions Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and cyan, magenta, and yellow are respectively performed by charging, exposure, development, and transfer processes. And a black image are sequentially formed.

  Photosensitive drums 1a, 1b, 1c, and 1d that carry visible images (toner images) of the respective colors are disposed in the image forming portions Pa to Pd, and are formed on the photosensitive drums 1a to 1d. The transferred toner image is transferred onto a transfer paper 6 carried and conveyed by a conveyor belt 8 that moves adjacent to each image forming unit, and further fixed on the transfer paper 6 by a fixing unit 7. It is configured to be discharged from the main body. An image forming process is performed on each of the photosensitive drums 1a to 1d while rotating the photosensitive drums 1a to 1d clockwise in FIG.

  Next, the image forming units Pa to Pd will be described. Around and around the photosensitive drums 1a to 1d rotatably arranged, image information is supplied to the chargers 2a, 2b, 2c and 2d for charging the photosensitive drums 1a to 1d and the photosensitive drums 1a to 1d. LED heads 17a, 17b, 17c and 17d to be exposed, developing devices 3a, 3b, 3c and 3d for forming toner images on the photosensitive drums 1a to 1d, and a developer remaining on the photosensitive drums 1a to 1d ( Cleaning portions 5a, 5b, 5c and 5d for removing toner are provided.

  First, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the chargers 2a to 2d, then irradiated with light by the LED heads 17a to 17d, and electrostatic charges corresponding to the image signals are applied to the photosensitive drums 1a to 1d. A latent image is formed. Each of the developing devices 3a to 3d is filled with a predetermined amount of cyan, magenta, yellow, and black toner by a replenishing device (not shown). The toner is supplied onto the photosensitive drums 1a to 1d by the developing units 3a to 3d and electrostatically attached to the toner corresponding to the electrostatic latent images formed by exposure from the LED heads 17a to 17d. An image is formed.

  The transfer paper 6 onto which the toner image is transferred is accommodated in a paper cassette 16 at the lower part of the apparatus, and is supplied onto the conveyor belt 8 via a paper feed roller 13a and a registration roller 13b, and the photosensitive drums 1a to 1d. It is conveyed to the position. A sheet made of dielectric resin is used for the conveyor belt 8, and a belt in which both ends thereof are overlapped and joined to form an endless shape or a seamless belt is used.

  The conveyor belt 8 is stretched between an upstream conveyor roller 10 and a downstream drive roller 11. When the conveyor belt 8 starts to rotate counterclockwise, the transfer paper 6 is transferred from the registration roller 13b to the conveyor belt. Is conveyed onto the conveyor belt 8 via a suction roller 14 provided on the most upstream side. A predetermined voltage is applied to the suction roller 14, and the transfer paper 6 is held on the transport belt 8 by an electrostatic suction force. At this time, the image writing signal is turned ON, and an image is formed on the uppermost photosensitive drum 1a at a predetermined timing. The cyan toner image on the photosensitive drum 1a is transferred onto the transfer paper 6 by applying an electric field to the lower portion of the photosensitive drum 1a with the transfer roller 4a to which a predetermined transfer voltage is applied. Thereafter, the transfer paper 6 is conveyed to the next image forming portion Pb, and a magenta toner image is transferred by the photosensitive drum 1b in the same manner as described above.

  Thereafter, yellow and black toner images are transferred by the photosensitive drums 1c and 1d by the same method as described above. These four-color images are formed with a predetermined positional relationship that is predetermined with respect to the transfer paper 6 in order to form a predetermined full-color image. Reference numerals 4b, 4c and 4d denote transfer rollers located below the photosensitive drums 1b to 1d. The transfer paper 6 onto which the four color toner images have been transferred is separated from the transport belt 8 and transported to the fixing unit 7. In addition, the photosensitive drums 1a to 1d after the toner images are transferred are prepared by the cleaning units 5a to 5d in preparation for new electrostatic latent images to be subsequently formed.

  The transfer paper 6 transported from the transport belt 8 to the fixing unit 7 is heated and pressed by the fixing roller 18 so that the toner image is fixed on the surface of the transfer paper 6 and a predetermined full-color image is formed. The transfer paper 6 on which the full color image is formed is then discharged out of the apparatus main body by the discharge roller 19.

  In an image forming apparatus using an electrophotographic process, in order to form an optimum image, it is necessary to control a transfer voltage to be applied when toner is transferred according to an environment such as temperature and humidity inside the apparatus. Generally, an environmental correction table is used for controlling the transfer voltage. Patent Document 1 discloses a method of applying a transfer voltage corresponding to the humidity detected by a humidity sensor using a humidity correction table, as shown in FIG. Specifically, a correction value corresponding to the humidity detected by the humidity sensor is selected from one humidity correction table with respect to a reference voltage determined by the type and size of the paper, and a final output value is determined by calculation. It is a method.

  In the block diagram shown in FIG. 6, the color image forming apparatus includes an interface control unit 20, a data analysis unit 21, an output mechanism control unit 22, an operation panel 23, and an output mechanism unit 24. The interface unit 20 is an interface unit that accepts print data from a host device (not shown). The data analysis unit 21 is a part that analyzes the print data sent by the drawing command, converts it into bitmap data, and transmits it to the output mechanism unit 24 via the output mechanism control unit 22.

  The output mechanism control unit 22 controls the output mechanism unit 24, and includes an AD converter 25, a reference value storage memory 26, an environment correction table storage memory 27, a calculation unit 28, and a DA converter 29. Has been. The output mechanism control unit 22 will be described below.

  The AD converter 25 receives a measured value of the humidity inside the apparatus from an after-mentioned humidity sensor 30 as an analog signal, converts it into a digital signal, and sends it to the environment correction table storage memory 27. The environmental correction table storage memory 27 stores an environmental correction table that records a correction value of a voltage corresponding to the humidity inside the apparatus, and outputs a correction value corresponding to the humidity to the calculation unit 28.

  The reference value storage memory 26 is a memory for storing a reference voltage corresponding to a humidity value inside the apparatus that is predetermined as a reference humidity. The calculation unit 28 performs calculation using the reference voltage value stored in the reference value storage memory 26 and the correction value output from the environment correction table storage memory 27 to determine the optimum transfer voltage value. . The voltage value determined by the calculation unit 28 is converted again into an analog signal via the DA converter 29 and sent to the output mechanism unit 24. The operation panel 23 includes an input unit through which an operator inputs operation conditions to the apparatus, and a display unit that notifies the operator of the operation state of the apparatus.

  The output mechanism unit 24 is a mechanism unit that transfers the toner image onto the transfer paper based on the control of the output mechanism control unit 22, and the humidity sensor 30 and the transfer unit unit 31 are arranged. The transfer unit 31 includes a high voltage controller 32 that controls a transfer voltage when transferring the toner, a high voltage power supply circuit 33 that supplies a transfer voltage to the photosensitive drum, and a toner image transferred onto the transfer paper together with the photosensitive drum. A transfer roller 4 is provided. The transfer unit 31 is provided for each of the image forming portions Pa to Pd, and the four transfer rollers 4a to 4d are arranged in each of the image forming portions Pa to Pd as shown in FIG. However, only one transfer unit 31 is described here for convenience of description. The voltage value set by the output mechanism control unit 22 is sent to the high voltage control unit 32, and an optimum voltage corresponding to the humidity inside the apparatus is supplied from the high voltage power supply circuit 33 to the transfer roller 4. Form an image with high image quality.

  Usually, since the setting of the transfer voltage greatly depends on the moisture absorption of the transfer paper, the temperature / humidity detecting means is often provided at a position as close to the outside of the machine as possible. However, when the transfer voltage during non-sheet passing, such as between sheets during continuous printing, is set according to the output of the temperature / humidity detection means located near the outside of the machine, the inside of the machine is warmed by the heat of the fixing unit, etc. The proper transfer voltage cannot be applied to the image, resulting in degradation of image quality, and the toner on the transport belt other than the transfer paper cannot be returned to the photosensitive drum, causing the paper to become dirty. There is a problem of doing.

In addition, in order to prevent the toner from adhering to the adsorption roller and to surely return the adhering toner to the belt, it is necessary to apply a voltage to the adsorption roller even between the papers. Similarly to the above, unless an appropriate voltage is applied to the suction roller with respect to the temperature inside the machine, the toner cannot be surely prevented from adhering to the suction roller, and the toner attached to the suction roller at the time of paper passing Will transfer to the transfer paper and stain will occur.
JP 2001-66834 A

  SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an image forming apparatus capable of selecting optimum transfer and suction conditions according to environmental conditions inside and outside the apparatus, when the transfer paper is passing and when it is not. For the purpose.

  In order to achieve the above object, the present invention provides an image forming unit including a photosensitive drum and a developing device, a transfer unit that transfers a toner image developed on the photosensitive drum onto a transfer sheet, and a temperature inside the device. And / or a first detecting means for detecting humidity and a second detecting means for detecting temperature and / or humidity outside the apparatus, and the apparatus detected by the first and second detecting means. In the image forming apparatus that controls the transfer voltage applied to the transfer unit according to internal and external temperature and / or humidity, the transfer voltage while the transfer sheet passes through the transfer unit is the second voltage. Control is performed according to the detection result of the detection means, and the transfer voltage in other cases is controlled according to the detection result of the first detection means.

  The present invention also provides a plurality of image forming units including a photoconductive drum and a developing device, transfer means for transferring a toner image developed on the photoconductive drum onto transfer paper, and transfer paper for each image forming unit. Conveying means for sequentially conveying, an adsorbing means for adsorbing the transfer paper to the conveying means, a first detecting means for detecting the temperature and / or humidity inside the apparatus, and a first detecting means for detecting the temperature and / or humidity outside the apparatus. And an image forming apparatus for controlling an adsorption voltage to be applied to the adsorption unit in accordance with temperature and / or humidity inside and outside the apparatus detected by the first and second detection units. In this case, the suction voltage while the transfer paper passes through the transfer means is controlled according to the detection result of the second detection means, and the suction voltage in the other cases is the first detection voltage. Control according to the detection result of the means It is characterized by a door.

  In the image forming apparatus having the above-described configuration, the transfer voltage or the suction voltage is controlled by controlling a current value or a voltage value output to the transfer unit or the suction unit. .

  According to the present invention, in the image forming apparatus configured as described above, a reference value storage memory for storing a reference current value or a reference voltage value necessary for setting the current value or the voltage value for controlling the transfer voltage or the adsorption voltage, Stores an environmental correction table used to correct the reference current value or reference voltage value according to the temperature and / or humidity inside and outside the apparatus detected by the detection means, and to set the necessary current value or voltage value. And an environmental correction table storage memory.

  According to the first configuration of the present invention, the transfer voltage when the transfer paper is passing through the transfer unit is changed according to the output of the unit for detecting the temperature or humidity outside the apparatus, and the optimum state is maintained. In other cases, however, the toner on the conveyor belt can be reliably returned to the photosensitive drum by changing the temperature or humidity in accordance with the output of the means for detecting the temperature or humidity in the machine, and the back side of the transfer paper. Dirt can be prevented.

  Further, according to the second configuration of the present invention, the adsorption voltage when the transfer paper passes through the transfer means is changed in accordance with the output of the means for detecting the temperature or humidity outside the apparatus and is in an optimum state. In other cases, the image is changed according to the output of the means for detecting the temperature or humidity in the apparatus, so that high-quality image formation is possible at the time of transfer. On the other hand, in other cases, scattering of the toner on the transfer paper and adhesion of the toner to the suction roller can be prevented, and the adhered toner can be reliably returned onto the belt.

  Further, according to the third configuration of the present invention, in the first or second configuration, the transfer voltage or the adsorption voltage can be controlled by any of the output current value or voltage value, and image formation is performed. Control mechanism choices when designing equipment.

  According to the fourth configuration of the present invention, in the third configuration, the environment for storing the environment correction table used for correcting the reference current value or the reference voltage value and setting the necessary current or voltage is stored. By providing the correction table storage memory, it becomes possible to control the transfer and adsorption voltage more quickly and accurately in accordance with the output of the means for detecting temperature and / or humidity.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the color image forming apparatus of the first embodiment. Portions common to FIG. 5 of the conventional example are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, an in-machine temperature / humidity sensor 34 that detects the temperature and / or humidity inside the apparatus and an outside temperature / humidity sensor 35 that detects the temperature / humidity outside the apparatus are provided. The in-machine temperature / humidity sensor 34 is, for example, around the driving roller 11 in FIG. 5 in the vicinity of the heat generating part such as a fixing unit or a motor, and the outside temperature / humidity sensor 35 is, for example, not easily affected by the heat generating part. It is installed near the intake duct (not shown) above the cassette 16, but it can also be installed in other places where the temperature and humidity inside and outside the apparatus can be accurately detected.

  The in-machine temperature / humidity sensor 34 and the out-of-machine temperature / humidity sensor 35 always detect the temperature / humidity inside and outside the apparatus at predetermined time intervals. The detected temperature and humidity are sent to the environment correction table storage memory 27 via the AD converter 25. In the environment correction table storage memory 27, as for the transfer voltage correction table and the adsorption voltage correction table, a total of four environment correction tables (one of which uses the outside temperature and humidity and one table which uses the inside temperature and humidity), respectively. (Not shown).

  When the detected temperature and humidity inside and outside the apparatus are sent to the environment correction table storage memory 27, the output mechanism control unit 22 causes the operation state of the apparatus to pass the transfer sheet on the transfer means. If the transfer paper is in the pass state, the correction value is selected by the corresponding environmental correction table using the temperature and humidity outside the apparatus detected by the external temperature and humidity sensor 35 and calculated. If it is in a state other than the transfer paper passing through, such as between papers, the correction value is selected by the corresponding environmental correction table using the temperature and humidity inside the apparatus detected by the temperature and humidity sensor 34 in the apparatus. The result is output to the calculation unit 28.

  For example, during continuous paper passing, the transfer voltage and adsorption voltage before passing the first transfer paper, between the papers during continuous paper passing, and after the last transfer paper passed, Correction is performed based on the temperature and humidity inside the apparatus detected by the humidity sensor 34. The correction of the transfer voltage and the adsorption voltage is preferably performed using the detection value immediately before the correction as much as possible, but the correction may be performed using the temperature and humidity detected at other timing. It is also possible to detect the temperature and humidity a predetermined number of times and use the average value of the detected values.

  Thereby, the transfer voltage and the suction voltage while the transfer paper is passing through the transfer means are changed according to the detection result of the outside temperature / humidity sensor 35, and the transfer voltage and the suction voltage in other cases are It can be changed according to the detection result of the temperature / humidity sensor 34, and the optimum transfer voltage and adsorption voltage are set for the transfer paper passing state and other states. The toner on the portion other than the latent image of the toner does not adhere to the conveyor belt, and a small amount of toner remaining on the conveyor belt can be returned to the photosensitive drum, so that the backside of the paper is not stained. Therefore, it is possible to provide a color image forming apparatus that can prevent and form a higher quality image.

  FIG. 2 is an explanatory diagram showing an example of an environmental correction table for correcting a transfer voltage used in the present invention. Here, the correction table in the case of using the outside temperature / humidity will be described, but the case of using the inside temperature / humidity is also explained in exactly the same way. In the figure, the environmental humidity H is assigned to each row of the environmental correction table from 4% to 98% at intervals of 4%, and the environmental temperature T is assigned to each column at intervals of 4 ° C. from 7 ° C. to 39 ° C. . When the external temperature and humidity sensor 35 detects the environmental temperature and humidity in the apparatus, a correction value at a position where rows and columns intersect corresponding to the detected temperature and humidity is selected. This example shows a correction table when the transfer voltage is controlled by correcting the current value output to the transfer roller, and the unit of each correction value in the correction table is μA (microampere). For example, when the temperature detected by the external temperature / humidity sensor 35 is 18 ° C. and the humidity is 50%, the correction value at the position where the row of 50 ≦ H <54 and the column of 15 ≦ T <19 intersect. -1 μA is selected.

  Based on the correction value selected by the environment correction table shown in FIG. 2, the calculation unit 28 corrects the reference current value and sets an optimum current value. For example, when the temperature detected by the external temperature / humidity sensor 35 is 15 ° C. and the humidity is 10%, the correction value −4 μA selected by the environment correction table 35 in FIG. Is added to set the current value. The set current value is transmitted to the high voltage controller 32, and an optimum current is output from the high voltage power supply circuit 33 to the transfer roller 4.

  In this example, the transfer voltage is controlled by selecting a correction value according to the temperature and humidity inside and outside of the apparatus from the environment correction table, and correcting the reference current value and outputting the optimum current. The data to be corrected is not limited to the current value, but can be a voltage value. The control using the voltage value is the same as the case of the current value except that a correction table for correcting the reference voltage value is used, and the description thereof will be omitted.

  FIG. 3 is an explanatory diagram showing an example of an environmental correction table for correcting the attracting voltage used in the present invention. Here, only the correction table when using the outside temperature / humidity will be described, and the same applies when the inside temperature / humidity is used. In the figure, the environmental humidity H is assigned to each row of the environmental correction table from 0% to 100% at intervals of 4%, and the environmental temperature T is assigned to each column at intervals of 4 ° C. from 9 ° C. to 37 ° C. . When the external temperature and humidity sensor 35 detects the environmental temperature and humidity in the apparatus, a correction value at a position where rows and columns intersect corresponding to the detected temperature and humidity is selected. This example shows a correction table in the case where the voltage value output to the suction roller is corrected to control the voltage applied to the suction roller, and the unit of each correction value in the correction table is V (volts). For example, when the temperature detected by the external temperature / humidity sensor 35 is 18 ° C. and the humidity is 50%, the correction value at the position where the row of 48 ≦ H <52 and the column of 17 ≦ T <21 intersect. -100V is selected.

  Based on the correction value selected by the environment correction table shown in FIG. 3, the calculation unit 28 corrects the reference voltage value and sets an optimum voltage value. For example, when the temperature detected by the external temperature / humidity sensor 35 is 15 ° C. and the humidity is 10%, the correction value −400 V selected by the environment correction table of FIG. The voltage value is set by addition. The set voltage value is transmitted to the high voltage control unit 32, and an optimum voltage is output from the high voltage power supply circuit 33 to the suction roller 14. In this example as well, the data to be corrected is not limited to the voltage value in the same way as the transfer voltage control, but can be a current value. The control using the current value is exactly the same as the case of the voltage value except that a correction table for correcting the reference current value is used.

  Next, the operation of the image forming apparatus of this embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing the operation at the time of image output in the color image forming apparatus of this embodiment. The operation at the time of image output will be described according to the steps of FIG. 4 with reference to FIG. Although the transfer voltage control operation will be described here, the adsorption voltage control can be performed in exactly the same manner.

  First, the operator operates the operation panel 23 to select a desired paper type and size (step 1). Next, the data of the selected paper type and size are transmitted to the reference value storage memory 26, and a reference current corresponding to the paper type and size is determined (step 2) and sent to the calculation unit 28. When printing is started by the operation panel 23 (step 3), the temperature and humidity inside and outside the apparatus detected by the in-machine temperature / humidity sensor 34 and the outside temperature / humidity sensor 35 are sent to the environment correction table storage memory 27. (Step 4). On the other hand, conveyance of transfer paper by the paper conveyance means is also started at the same time.

  Next, it is determined whether or not the state of the apparatus is a state where the transfer paper is passing the transfer roller (step 5). If it is determined that the transfer paper has passed, the correction value is selected by the transfer voltage correction table in the environment correction table storage memory 27 based on the temperature and humidity outside the apparatus detected by the external temperature and humidity sensor 35. (Step 6). The transfer control value is calculated by the calculation unit 28 using the correction value selected in step 6 (step 7), the reference current determined in step 2 is corrected by this transfer control value, and the optimum current value is set. (Step 8).

  By outputting the set current value to the high voltage control unit 32 in the transfer unit unit 31, transfer is performed to the transfer paper that has been carried out by applying an optimum transfer voltage to the transfer roller 4 from the high voltage power supply circuit 33. (Step 9). The transferred transfer paper passes through a fixing unit (not shown) and is discharged to the outside of the apparatus (step 10).

  If it is determined in step 6 that the transfer paper has not passed, the correction value is determined by the transfer voltage correction table in the environment correction table storage memory 27 based on the temperature and humidity inside the apparatus detected by the in-machine temperature / humidity sensor 34. Selected (step 11). The control value is calculated by the calculation unit 28 using the correction value selected in step 11 (step 12), the reference current determined in step 2 is corrected by this control value, and the current value when no paper is passed is set. (Step 13).

  By outputting the set current value to the high voltage control unit 32 in the transfer unit 31, an optimum voltage is applied to the transfer roller 4 from the high voltage power supply circuit 33 (step 14). As a result, the toner remaining on the conveyance belt can be reliably returned to the photosensitive drum, and the toner returned on the photosensitive drum is not reattached to the conveyance belt (step 15). In this example, the transfer voltage at the time of passing the transfer paper and at other times is controlled by outputting an optimum current value, but a voltage value may be outputted instead of the current value.

  In each of the above embodiments, the optimum transfer voltage is set using an environment correction table corresponding to temperature and humidity, but for example, either temperature or humidity is detected by a temperature sensor or humidity sensor, It is also possible to set the transfer voltage using an environment correction table corresponding to only one of temperature and humidity.

  In each of the above embodiments, the voltage applied to both the transfer roller and the suction roller is controlled. However, only the voltage applied to either the transfer roller or the suction roller is controlled. You can also In addition, although a color image forming apparatus including a plurality of image forming units has been described, the present invention is not limited to this, and can be applied to an image forming apparatus for forming a monochrome image.

  The present invention detects an image forming unit including a photosensitive drum and a developing device, transfer means for transferring a toner image developed on the photosensitive drum onto transfer paper, and temperature and / or humidity inside the device. A first detection means and a second detection means for detecting temperature and / or humidity outside the apparatus, and the temperature inside and outside the apparatus detected by the first and second detection means and / or Alternatively, in the image forming apparatus that controls the transfer voltage applied to the transfer unit according to humidity, the transfer voltage while the transfer sheet passes through the transfer unit is determined according to the detection result of the second detection unit. The transfer voltage in other cases is controlled according to the detection result of the first detection means. As a result, for example, when the sheet is not passed between sheets, the residual toner on the conveying unit is reliably removed by returning it to the photosensitive drum, and the toner returned on the photosensitive drum is reattached to the conveying unit. Therefore, the present invention provides a color image forming apparatus that forms a high-quality image that does not cause paper back stain.

  In addition, a plurality of image forming units including a photosensitive drum and a developing device, transfer means for transferring a toner image developed on the photosensitive drum onto transfer paper, and transfer paper are sequentially conveyed to each image forming unit. A conveying means; an adsorbing means for adsorbing the transfer paper to the conveying means; a first detecting means for detecting the temperature and / or humidity inside the apparatus; and a second detection for detecting the temperature and / or humidity outside the apparatus. And an image forming apparatus for controlling an adsorption voltage to be applied to the adsorption means according to the temperature and / or humidity inside and outside the apparatus detected by the first and second detection means. The suction voltage while the paper is passing through the transfer means is controlled according to the detection result of the second detection means, and the suction voltage in other cases is detected by the first detection means. To control according to the results There. As a result, a high-quality image is formed at the time of transfer, and toner scattering on the transfer paper and toner adhesion to the suction roller can be prevented at the time of non-transfer, and the adhering toner can be reliably returned onto the belt.

  In addition, since the transfer voltage or the adsorption voltage can be controlled by using any of the output current value or voltage value, the options of the control mechanism are widened, and the image forming apparatus can be designed more freely.

  In addition, a current value for controlling the transfer voltage or the adsorption voltage, or a reference value storage memory for storing a reference current value or a reference voltage value necessary for setting the voltage value, and internal and external temperatures detected by the detection means and / or Or an environment correction table storage memory that stores an environment correction table used to correct a reference current value or a reference voltage value according to humidity and set a necessary current value or voltage value. Provided is an image forming apparatus capable of controlling a transfer voltage or an adsorption voltage more quickly and accurately according to the output of a means for detecting humidity.

FIG. 1 is a block diagram illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention. These are examples of a transfer current correction table used in the present embodiment. These are an example of the adsorption voltage correction table used in this embodiment. FIG. 5 is a flowchart illustrating an operation at the time of image output in the image forming apparatus of the present embodiment. FIG. 1 is a schematic configuration diagram showing a conventional image forming apparatus. FIG. 2 is a block diagram illustrating a configuration of a conventional image forming apparatus.

Explanation of symbols

1a-1d. Photosensitive drum 4. Transfer roller 8. 8. Conveyor belt Detection means 14. Adsorption roller 22. Output mechanism controller 24. Output mechanism section 26. Reference value storage memory 27. Environment correction table storage memory 28. Calculation unit 30. Humidity sensor 31. Transfer unit section 32. High pressure controller 33. High voltage power supply circuit 34. In-machine temperature and humidity sensor 35. External temperature and humidity sensor

Claims (4)

An image forming unit including a photosensitive drum and a developing device, transfer means for transferring a toner image developed on the photosensitive drum onto a transfer sheet, and a first detection for detecting temperature and / or humidity inside the device Means, and second detection means for detecting temperature and / or humidity outside the apparatus,
In the image forming apparatus for controlling the transfer voltage applied to the transfer unit according to the temperature and / or humidity inside and outside the apparatus detected by the first and second detection units,
The transfer voltage while the transfer paper is passing through the transfer means is controlled according to the detection result of the second detection means, and the transfer voltage in other cases is controlled by the first detection means. An image forming apparatus controlled according to a detection result. A plurality of image forming units including a photosensitive drum and a developing device; transfer means for transferring a toner image developed on the photosensitive drum onto transfer paper; and conveying means for sequentially transferring the transfer paper to each image forming unit An adsorbing means for adsorbing the transfer paper to the conveying means, a first detecting means for detecting the temperature and / or humidity inside the apparatus, and a second detecting means for detecting the temperature and / or humidity outside the apparatus. Have
In the image forming apparatus for controlling the suction voltage applied to the suction means according to the temperature and / or humidity inside and outside the apparatus detected by the first and second detection means,
The suction voltage while the transfer paper passes through the transfer means is controlled according to the detection result of the second detection means, and the suction voltage in the other cases is the same as that of the first detection means. An image forming apparatus controlled according to a detection result.   The image forming apparatus according to claim 1, wherein the transfer voltage or the suction voltage is controlled by controlling a current value or a voltage value output to the transfer unit or the suction unit. .   A current value for controlling the transfer voltage or the adsorption voltage, or a reference value storage memory for storing a reference current value or a reference voltage value necessary for setting the voltage value; and internal and external temperatures detected by the detection means; And / or an environment correction table storage memory for storing an environment correction table used for correcting the reference current value or the reference voltage value according to humidity and setting a necessary current value or voltage value. The image forming apparatus according to claim 3.

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