JP2013142861A - Image forming apparatus, control method thereof, computer-readable program, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable setting of an appropriate separation blow amount to a blow part even when a toner attachment amount is uneven in a tip area of a sheet, and accurate execution of the control for separation between the sheet after fixation and a fixation discharge roller and the like.SOLUTION: An image forming apparatus comprises: a blow control part 55 for setting a plurality of blow allotment areas corresponding to a tip area of a sheet P, and respective blow amounts therefor, and performing a blow control on motors 61-63 for blower fans so as to gain the set blow amounts; an area setting part 52 for setting determination areas by dividing, into eight areas, the blow allotment areas that is subjected to the aforementioned blow control; a printing ratio calculation part 53 for inputting density information of an image formed in the tip area of the sheet P, and calculating a printing ratio based on the density information of the image for each of the eight determination areas set in the blow allotment areas divided by the area setting part 52; and a blow amount setting part 54 for setting, to the blow control part 55, blow amounts corresponding to the printing ratio of the eight determination areas calculated as described above.

Description

  The present invention relates to a color or black-and-white printer, a copying machine, or a complex machine having a function of blowing air between a sheet on which an image is formed and a fixing discharge roller that conveys the sheet. The present invention relates to an image forming apparatus suitable for application, a control method thereof, a computer-readable program, and a recording medium.

  In recent years, there have been color printers that form color images based on color image information, color copiers that have a scan function that reads an image of an original and outputs an image signal for color image reproduction, and multifunction devices. It has been increasingly used. For example, digital color image forming apparatuses that acquire red (R), green (G), and blue (B) image data and form a color image based on the image data are widely used.

  In this type of tandem color image forming apparatus, an electrophotographic image forming unit is provided. In the image forming unit, RGB image data is color-converted into YMCK image data, and yellow ( A color toner image is formed based on image data for Y, magenta (M), cyan (C), and black (BK) colors. The image forming unit includes image forming units that share Y, M, C, and BK image forming output functions, and image data is applied to a photosensitive drum that is uniformly charged by the charging unit for each image forming color. Based on the above, an electrostatic latent image is formed by an optical writing unit (laser scanning type print head) using a polygon mirror and an optical writing unit (LPH: LED Print Head) using an LED array.

  The electrostatic latent image is developed by the developing device for each image forming color. The color toner image formed on the photosensitive drum by performing such charging, exposure and development is superimposed on the intermediate transfer belt, and the superimposed color toner image is transferred onto the sheet by the transfer unit. The sheet is transported from the sheet feeding tray to the transfer section by the sheet feeding section. The toner image transferred onto a predetermined sheet is fixed by a fixing device. Thereby, a color image based on the image data can be formed on a predetermined sheet.

  By the way, according to the color image forming apparatus, a function of separating the paper discharged from the image forming unit to the fixing device and subjected to the fixing process from the fixing paper discharge roller is used. With respect to an image forming apparatus having this type of sheet separation function, the stencil printing apparatus disclosed in Patent Document 1 includes a drum, a separation pump, a drum motor, and a sheet feeding device. The drum is driven by a drum motor, and a stencil sheet is mounted on the outer peripheral surface thereof and rotated. The paper feeding device feeds printing paper to the outer peripheral surface of the rotating drum. The paper feeding device conveys the printing paper along with the rotation of the drum while applying a printing pressure to the printing paper. A separation pump using a drum motor as a driving source generates a strong wind for separation, transfers the image from the stencil sheet to the printing paper, and when the printing paper conveyance tip comes downstream of the image transfer position, the printing paper conveyance tip A strong wind for separation is instantaneously blown between the drum and the outer peripheral surface of the drum.

  The control system of the separation pump controls the on / off of the separation pump according to the printing state of the printing paper. When the separation pump is turned on, the drum rotation speed is printed at an economy speed lower than the maximum speed or less. . On the premise of these, Patent Document 1 determines the printing state of the printing paper using the printing rate at the leading end side of the printing paper and the printing position in the vertical direction of the printing paper as judgment elements. When the stencil printing machine is configured in this way, when the separation pump is turned on, the load on the separation pump is applied to the drum motor, but the drum motor load is kept below the economy speed, so the load on the drum motor is kept to a small load. It can be done.

  Further, in relation to an image forming apparatus having a function of separating paper after fixing, the fixing device disclosed in Patent Document 2 is configured to include a heating member, a pressure member, a peeling device, and a control device. The In the fixing device, when the sheet is conveyed to the pressure contact portion between the heating member and the pressure member, the toner image on the processing surface of the sheet that contacts the heating member is thermally melted and fixed on the processing surface. The heating member heats and fixes the sheet after the toner image is formed. The pressure member is pressed against the heating member. The peeling device includes a plurality of nozzles arranged in parallel along a direction parallel to the leading edge of the conveyed sheet, and is disposed on the downstream side in the sheet conveying direction from the press contact portion. The peeling device blows compressed air from each nozzle toward the sheet and the heating member to peel the sheet from the heating member.

  Based on these assumptions, in Patent Document 2, the control device inputs position information indicating the toner image formation position on the processing surface from the image forming apparatus, and on / off of each nozzle of the peeling device based on the position information. And switch. At that time, the control device controls the peeling device so that the compressed air hits the toner image and a portion where the compressed air does not hit the region where the toner image is not formed on the processing surface. When the image forming apparatus is configured in this manner, the cooling of the heating member by the compressed air can be suppressed without reducing the sheet peeling effect.

JP 2004-106520 A JP 2011-017866 A

Incidentally, the image forming apparatus having a sheet separation function after the fixing process according to the conventional example has the following problems.
i. In general, when air is blown between a sheet and a fixing paper discharge roller to improve the separation of the sheet, the separation increases as the air volume increases. However, it is necessary to set the air volume small in terms of preventing hot air from flowing into other locations, preventing paper wrinkles, and reducing power consumption.

  ii. According to the stencil printing apparatus provided with the separation pump found in Patent Document 1, the separation pump is switched ON / OFF according to the printing rate of the leading end portion of the paper. However, according to Patent Document 1, since the air volume is set based on the full width of the paper, the current situation is that an appropriate air volume cannot be set.

  ii. According to the image forming apparatus that performs the separation control as described in Patent Document 2, the control apparatus switches the plurality of nozzle positions by controlling the ON / OFF of the air blowing section depending on the presence or absence of an image. However, if a portion where the toner adhesion amount is large is a part of the front end region of the paper, winding around the fixing paper discharge roller or the like is likely to occur. Moreover, when the air volume is set based on the blowing width of the nozzle, it is necessary to provide a large number of blowing sections. In particular, when there is a bias in the amount of toner adhering to the leading edge area of the paper, there is a problem that it is difficult to realize appropriate air volume control at low cost.

  Accordingly, the present invention solves the above-described problem, and even when there is a bias in the toner adhesion amount at the front end region of the paper, an appropriate separation air amount can be set in the air blowing unit, An object of the present invention is to provide an image forming apparatus, a control method thereof, a computer-readable program, and a recording medium capable of accurately performing separation control between a fixed sheet and a fixing discharge roller.

  In order to solve the above problem, the image forming apparatus according to claim 1 blows air between the image forming unit, a sheet on which an image is formed by the image forming unit, and a sheet conveying unit that conveys the sheet. In an image forming apparatus including a blower unit, a plurality of blower sharing areas are set with respect to a front end region of the paper, and an air volume is set, and the blower unit is controlled to blow so that the set air volume is obtained. A blower control unit, a region setting unit that sets a plurality of determination regions by dividing the blower assignment region controlled by the blower control unit into two or more, and density information of an image formed in the leading end region of the paper A print rate calculation unit that calculates a print rate based on the density information of the image for each of the plurality of determination regions set in the air distribution region divided by the region setting unit, and the print rate calculation Calculated by part It is characterized in further comprising an air volume setting unit for setting a flow rate corresponding to the printing rate of the plurality of determination areas, which are in the air blow control unit.

  According to the image forming apparatus of the first aspect, the image forming unit forms an image on the paper. The blower blows air between a sheet on which an image is formed by the image forming unit and a sheet conveying unit that conveys the sheet. The air blowing control unit sets a plurality of air blowing sharing regions with respect to the front end region of the paper, sets the air volume, and controls air blowing of the air blowing unit so that the air volume is set. The region setting unit sets a plurality of determination regions by dividing a blower assignment region that is controlled by the blow control unit into two or more. The printing rate calculation unit inputs density information of the image formed in the leading end area of the paper, and prints based on the density information of the image for each of a plurality of determination areas set in the air distribution area divided by the area setting unit. Calculate the rate. Based on these assumptions, the air volume setting unit sets the air volume corresponding to the printing rates of the plurality of determination areas calculated by the printing rate calculation unit in the air blowing control unit.

  With this air volume setting, if the printing rate of the image formed in the leading edge area of the paper is high, it can be set so that the air volume increases, and if the printing rate is low, it can be set so that the air volume decreases. Even if there is a bias in the amount of toner adhering to the front end region of the paper, an appropriate separation air volume can be set in the blower.

  The image forming apparatus according to claim 2 is the image forming apparatus according to claim 1, wherein the air volume setting unit performs maximum printing for each of the blower sharing areas from among the printing rates of the plurality of determination areas calculated by the printing rate calculation unit. A rate is extracted, and an air volume corresponding to the maximum printing rate is set in the air blowing control unit.

  According to a third aspect of the present invention, in the first aspect, the air volume setting unit switches the setting of the air volume according to the printing rate according to the type and basis weight of the paper. Is.

  An image forming apparatus according to a fourth aspect of the present invention is the image forming apparatus according to the first aspect, wherein the air volume setting unit is configured to determine the determination area in the paper conveyance direction that is treated as an area for calculating the printing rate according to the type and basis weight of the paper. The length is switched.

  The image forming apparatus according to a fifth aspect of the invention is the image forming apparatus according to the first aspect, wherein the air volume setting unit is configured to determine the determination area in the paper width direction that is treated as an area for calculating the printing rate according to the type and basis weight of the paper. The number of divisions is switched.

  The image forming apparatus according to a sixth aspect is the image forming apparatus according to the first aspect, wherein a fan is provided in the air blowing unit, and the air blowing control unit controls the air volume based on the rotational speed of the fan.

  An image forming apparatus according to a seventh aspect is the image forming apparatus according to the first aspect, wherein a shutter having a shielding plate is provided in the air blowing unit, and the air blowing control unit controls an air volume by a degree of opening and closing of the shielding plate. To do.

  An image forming apparatus according to an eighth aspect of the present invention is the image forming apparatus according to the first aspect, wherein a pressure pump is provided in the air blowing unit, and the air blowing control unit controls an air volume by a pressure applied when the pressure pump is injected. It is what.

  According to a ninth aspect of the present invention, there is provided a control method for an image forming apparatus comprising: an image forming apparatus including a paper on which an image is formed and a blower that blows air between a paper transport unit that transports the paper; A step of setting a plurality of air blowing areas, setting an air volume, controlling the air flow of the air blowing unit so that the air volume is set, and dividing the air air sharing area to be air blown into two or more And a step of setting a plurality of determination areas, a step of inputting density information of an image formed in the leading edge area of the sheet, and a plurality of the determination areas set in the divided air-sharing area, The step of calculating the printing rate based on the density information of the image and the step of setting the air volume corresponding to the calculated printing rate of the plurality of determination areas in the blower unit are performed. .

  The computer-readable program according to claim 10 is a program for controlling an image forming apparatus including a sheet on which an image is formed and a blower unit that blows air between a sheet conveyance unit that conveys the sheet. A program capable of executing the control method of the image forming apparatus according to claim 9.

  The recording medium according to claim 11 is a recording in which a program for controlling an image forming apparatus including a sheet on which an image is formed and a blower that blows air between a sheet conveying unit that conveys the sheet is described. A computer-readable program for executing the image forming apparatus control method according to claim 9 is described.

  According to the image forming apparatus according to claim 1 and the control method of the image forming apparatus according to claim 9, the air blowing unit that blows air between the sheet on which the image is formed and the sheet conveying unit that conveys the sheet is blown. When performing the control, the air volume setting unit sets the air volume corresponding to the printing rate based on the density information of the image formed in the leading edge region of the paper in the air blowing control unit.

  With this configuration, when the printing rate of the image formed on the leading edge region of the paper is high, the air volume can be set to be increased, and when the printing rate is low, the air volume can be set to be low. Even when there is a bias in the amount of toner adhering to the tip region, an appropriate amount of separation air can be set in the blower. Therefore, separation control between the fixed paper and the fixing paper discharge roller can be executed with high accuracy. As a result, compared to the conventional method, it has become possible to improve in many aspects, such as an improvement in separability by blowing air, prevention of inflow of hot air, prevention of paper wrinkles, and reduction in power consumption, without unnecessarily increasing the number of air blowing units.

  According to the image forming apparatus of the second aspect, since the air volume setting unit sets the air volume corresponding to the extracted maximum printing rate in the air blowing control unit, the air volume setting unit sets a larger amount of air than the determination area where the printing rate is low. become able to.

  According to the image forming apparatus of the third aspect, since the air volume setting unit switches the setting of the air volume according to the printing rate according to the type and basis weight of the paper, it is difficult to wrap around the paper conveyance unit such as the fixing paper discharge roller. It is possible to set a larger amount of airflow to plain paper having a smaller basis weight (lighter) than paper having a paper type and basis weight.

  According to the image forming apparatus of the fourth aspect, since the air volume setting unit switches the length of the determination area in the paper conveyance direction, which is handled as the area for calculating the printing rate, according to the type and basis weight of the paper, The length of the determination region in the paper conveyance direction of plain paper having a small basis weight (light) can be expanded as compared with paper having a paper type and basis weight that is difficult to wind around a paper conveyance unit such as a roller. As a result, it is possible to set a large amount of air flow to plain paper with a small basis weight (light).

  According to the image forming apparatus of the fifth aspect, the air volume setting unit switches the number of divisions of the determination area in the paper width direction, which is handled as the area for calculating the printing rate, according to the type and basis weight of the paper. It is possible to set a larger number of divisions in the determination area in the paper width direction of plain paper having a small basis weight (lighter) than paper having a paper type and basis weight that are difficult to wind around a paper transport unit such as a paper discharge roller. As a result, it is possible to set a large amount of air flow to plain paper with a small basis weight (light).

  According to the image forming apparatus of the sixth aspect, since the fan is provided in the air blowing unit, and the air blowing control unit controls the air volume by the rotation speed of the fan, the paper type that is difficult to be wound around the paper conveying unit such as the fixing paper discharge roller. In addition, the air volume to plain paper having a small basis weight (light) can be set very finely as compared with paper having a basis weight.

  According to the image forming apparatus of the seventh aspect, the shutter having the shielding plate is provided in the air blowing unit, and the air blowing control unit controls the air volume by the degree of opening / closing of the shielding plate. Compared with paper with a paper type and basis weight that is difficult to wind around the paper transport unit, the air volume to plain paper with a small basis weight (light) can be set instantaneously.

  According to the image forming apparatus of the eighth aspect, since the pressure pump is provided in the blower unit, and the blower control unit controls the air volume by the pressure applied at the time of injection of the pressurization pump, Compared with paper of a paper type and basis weight that are difficult to wrap around the paper, it is possible to instantaneously set the air volume to plain paper with a small basis weight (light).

  According to a computer-readable program according to claim 10 and according to claim 11, the present invention includes an air blowing section that blows air between a sheet on which an image is formed and a sheet conveying section that conveys the sheet. Such an image forming apparatus can be controlled with good reproducibility.

1 is an explanatory diagram showing a configuration example of a color copying machine 100 as an embodiment according to the present invention. 3 is a block diagram illustrating a configuration example of a blower fan control unit 15 in the color copying machine 100 as the first embodiment. FIG. It is explanatory drawing which shows the setting example (the 1) of the determination area | region of ventilation allocation area | regions (1)-(3) and a printing rate. (A) And (B) is a table | surface figure which shows the example of storage of the setting value of the air volume corresponding to a printing rate. (A) And (B) is a table | surface figure which shows the example of data storage before and behind extraction of the maximum printing rate. It is explanatory drawing which shows the setting example (the 2) of the determination area | region of ventilation allocation area | regions (1)-(3) and a printing rate. (A) And (B) is explanatory drawing which shows the example of a data storage before and behind extraction of the maximum printing rate. It is explanatory drawing which shows the setting example (the 3) of the determination area | region of ventilation allocation area | regions (1)-(3) and a printing rate. (A) And (B) is explanatory drawing which shows the example of a data storage before and behind extraction of the maximum printing rate. 6 is a flowchart illustrating an example of air volume setting based on a maximum image printing rate in the blower fan control unit 15; It is a block diagram which shows the structural example of the shutter mechanism 70 as a 2nd Example.

  Hereinafter, an image forming apparatus, a control method thereof, a computer-readable program, and a recording medium according to an embodiment of the present invention will be described with reference to the drawings. The descriptions in this section do not limit the technical scope described in the claims or the meaning of terms.

  A color copying machine 100 shown in FIG. 1 constitutes an example of an image forming apparatus according to the present invention, and includes a copying machine main body 101 and a large paper feeding device 200. The copier main body 101 includes, for example, a blower fan control unit 15 as shown in FIG. 2 in addition to the paper supply unit 20, the paper reversing mechanism 24, the operation display panel 48, the color printer 80, and the scanner 102. .

The paper supply unit 20 includes, for example, three paper supply trays 21, 22 and 23 in order to supply the paper P to the color printer 80. In the paper feed tray 21, for example, a sheet P of A3 size, plain paper is used, and a basis weight is 120 g / m ² is stored. In the paper feed tray 22, for example, a paper P having an A3 size, a paper type of coated paper, and a basis weight of 100 g / m ² is stored. In the paper feed tray 23, for example, paper P having A3 size, plain paper type, and basis weight of 70 g / m ² is stored.

  A color printer 80 constituting an example of an image forming unit is connected to the paper supply unit 20. The color printer 80 forms a color image on the paper P and discharges it. For the color printer 80, for example, a tandem type electrophotographic printer engine is used. According to the color printer 80, RGB image data is color-converted into YMCK image data, and the yellow (Y), magenta (M), cyan (C), and black (BK) colors after color conversion. A color toner image is formed based on the image data for use.

  The color printer 80 includes image forming units that share image forming output functions of Y, M, C, and BK colors, and image data is applied to a photosensitive drum that is uniformly charged by a charging unit for each image forming color. An electrostatic latent image is formed by an optical writing unit (laser scanning type print head) using a polygon mirror and an optical writing unit (LPH: LED Print Head: hereinafter referred to as LPH90) using an LED array. The

  The electrostatic latent image is developed by the developing device for each image forming color. The color toner image formed on the photosensitive drum after being charged, exposed and developed in this manner is superimposed on the intermediate transfer belt, and the superimposed color toner image is transferred onto the paper P by the transfer unit. . The paper P is conveyed from the paper feed tray 21 and the like to the transfer unit by the paper supply unit 20. The toner image transferred onto the predetermined paper P is fixed by the fixing device 17. The fixed sheet P is discharged to the discharge tray 25 by the fixing discharge roller 17a. Thereby, a color image based on the image data can be formed on the predetermined paper P.

  On the copying machine main body 101, an operation display panel 48, a scanner 102, and the like are provided. The operation display panel 48 is operated so as to set image forming conditions in the normal operation mode. The normal operation mode refers to an operation for forming an image on a sheet of a predetermined paper size based on image forming conditions set by the user. The image forming conditions include basic setting, output setting, application setting, paper setting, print mode, image quality adjustment, and the like.

  The operation display panel 48 includes a touch panel and a liquid crystal display (LCD). The operation display panel 48 uses GUI (Graphic User Interface) input means. For example, when paper is set, an operation for selecting the paper feed trays 21 to 23 in which the paper P is stored is performed.

  Of course, when selecting the type (paper) of the paper P, the paper size, or the like, or selecting the paper feed trays 21 to 23, “Auto” is touched, and the image forming conditions are set. The image forming conditions and paper feed tray selection information set on the operation display panel 48 are output to a higher-level image control control unit (not shown). Operation data indicating image forming conditions set on the operation display panel 48 is stored in a job management memory or the like for managing image forming jobs. The image forming conditions and the like are displayed on the operation display panel 48 based on the display data. The display data is output to the operation display panel 48 from an upper control unit for image control.

  The scanner 102 includes a line image sensor, a scanner control unit, and the like that constitute a document image scanning exposure apparatus (not shown). The line image sensor reads a document based on a reading instruction operation from the operation display panel 48 and the control of the scanner control unit, and outputs image data DIN obtained by the reading to a higher-level image control control unit.

A paper reversing mechanism 24 is provided on the left side of the paper supply unit 20. The paper reversing mechanism 24 reverses the front and back of the paper P after the fixing process and re-feeds it to the color printer 80. Further, a large paper feeder 200 (PFU) is connected to the copying machine main body 101, and in order to feed the paper P to the color printer 80 separately from the paper supply unit 20, for example, two paper feed trays 201. , 202. In the paper feed tray 201, for example, paper P having A3 size, plain paper type, and basis weight of 120 g / m ² is stored. In the paper feed tray 202, for example, a paper P having an A3 size, a paper type of coated paper, and a basis weight of 100 g / m ² is stored. Thus, the entire color copying machine 100 is configured.

  Next, a configuration example of the blower fan control unit 15 according to the first embodiment of the color copying machine 100 will be described with reference to FIG. The blower fan control unit 15 illustrated in FIG. 2 includes a memory unit 51, a region setting unit 52, a printing rate calculation unit 53, an air volume setting unit 54, and a blower control unit 55. The blower fan control unit 15 includes a central processing unit (CPU), and functions of storage, area setting, printing rate calculation, air volume setting, and blower control are implemented in the central processing unit.

  The memory unit 51 stores page-unit image data DIN. In the case of a color image, the image data DIN is obtained from image data Dy for Y color image formation, image data Dm for M color image formation, image data Dc for C color image formation, and image data Dk for BK color image formation. Composed. In the image data DIN, the image density is managed in units of lines in the sheet width direction (main scanning direction) and in units of lines in the sheet conveyance direction (sub-scanning direction) from the writing start position of the page. The image density information can be extracted. A general-purpose RAM or the like is used for the memory unit 51. Hereinafter, the image data Dy, Dm, Dc, and Dk are collectively referred to as RAM data D50.

  An area setting unit 52 is connected to the memory unit 51. The area setting unit 52 receives the RAM data D50, and divides each of the air blowing assigned areas controlled by the air blowing control unit 55 into two or more and sets a plurality of determination areas. The area setting unit 52 outputs determination area setting information D52 for setting a determination area to the printing rate calculation unit 53 and the air volume setting unit 54. Here, the blower sharing area refers to an area for sharing the air blown between the paper P on which the image is formed and the paper transport unit that transports the paper P. The determination area is an area for determining the printing rate [%] when evaluating the toner adhesion amount of the image formed on the leading end area of the paper P.

  A printing rate calculation unit 53 is connected to the area setting unit 52 and the memory unit 51. The printing rate calculation unit 53 receives the RAM data D50 and the determination area setting information D52, and is formed in the leading end area of the paper P for each of a plurality of determination areas set in the blower sharing area divided by the area setting unit 52. The printing rate based on the density information of the obtained image is calculated. The printing rate calculation unit 53 outputs printing rate calculation information D53 indicating the printing rate [%] obtained by the calculation to the air volume setting unit 54.

  The density information of the image at the time of calculating the printing rate is obtained by reading the RAM data D50 from the memory unit 51 and extracting the density information of the image formed in the leading end area of the paper P from the RAM data D50. An arithmetic unit (ALU) is used for the printing rate calculation unit 53. The printing rate [%] is calculated by setting the maximum density Dmax at which the toner adhesion amount is maximum to 100%, and the density of the image is calculated as a ratio to the maximum density Dmax.

  An air volume setting unit 54 is connected to the area setting unit 52 and the printing rate calculation unit 53 described above. The air volume setting unit 54 sets the air volume [%] corresponding to the printing rate [%] of the plurality of determination areas calculated by the printing rate calculating unit 53 in the air blowing control unit 55.

  For example, a ROM 56 constituting an example of a recording medium is connected to the air volume setting unit 54. The ROM 56 stores a reference table in which the range [%] of the printing rate [%] is associated with, for example, two kinds of setting values of the air volume [%] (see FIGS. 4A and 4B). The ROM 56 outputs the reference data D56 in which the range [%] of the printing rate [%] and the set values of the two types of air volumes [%] are associated to the air volume setting unit 54.

  The air volume setting unit 54 receives, for example, the determination area setting information D52, the printing rate calculation information D53, and the reference data D56, and blows air from the printing rates [%] of the plurality of determination areas calculated by the printing rate calculation unit 53. The maximum printing rate [%] is extracted for each sharing area, and the air volume [%] corresponding to the maximum printing rate [%] is set in the blower control unit 55. The air volume setting unit 54 outputs air volume setting information D54 for setting the air volume [%] corresponding to the maximum printing rate [%] to the air blow control unit 55.

  In addition to the reference table, the ROM 56 stores a control program. The control program is control information for realizing a blower fan control method in the color copying machine 100, for example. For example, when the power is turned on, the control program is read from the ROM 56 to the memory unit 51 including a general-purpose RAM, and the area setting unit 52, the printing rate calculation unit 53, and the like are based on the control program. Setting, printing rate calculation, etc. are executed.

  In this ROM 56, the color copying machine 100 having a blower for blowing air between the sheet P on which the image is formed and the fixing sheet discharge roller 17a that discharges the fixed sheet P is stored in the ROM 56. A step of setting a plurality of air-sharing regions (1) to (3) with respect to the tip region, setting an air volume [%], and controlling air flow of the air-blowing unit so that the air volume [%] is set; A step of dividing the air blowing control areas (1) to (3) to be blown into two or more and setting a plurality of determination areas; and a step of inputting density information of an image formed in the leading edge area of the paper P; Calculating a printing rate [%] based on image density information for each of a plurality of determination areas set in the divided air distribution areas (1) to (3), and calculating the plurality of determination areas The air volume [%] corresponding to the printing rate [%] is set in the blower section. And-up, the computer executable control program is written.

  The air volume control unit 55 is connected to the air volume setting unit 54, and the air flow control unit 55 inputs the air volume setting information D54 and, for example, three air distribution areas as shown in FIG. (1) to (3) are set, and the air volume [%] is set in the air blower, and the air flow is controlled so that the air flow [%] is set in the air blower. The blower share areas (1) and (3) are set at the end of the printable width, and the blower share area (2) is set at the center of the printable width sandwiched between the blower shared areas (1) and (3). Is done. Here, the printable width refers to a width depending on an image forming effective area in the main scanning direction of the photosensitive drum in the image forming unit 80.

  The blower control unit 55 is connected with three blower fan driving motors 61 to 63 that constitute a part of the blower unit. The motor 61 is connected to a blower fan 64 that constitutes an example of a blower, and drives the blower fan 64 at a predetermined rotational speed based on a motor drive signal S61. The motor drive signal S61 is a signal for controlling the motor 61, and is output from the blow control unit 55 to the motor 61. The blower fan 64 is provided in the blower sharing area (1), and blows air between the paper P on which an image is formed by the image forming unit and a paper transport unit that transports the paper P, for example, a fixing paper discharge roller. To blow.

  The motor 62 is connected to the blower fan 65, and drives the blower fan 65 at a predetermined rotational speed based on the motor drive signal S62. The motor drive signal S <b> 62 is a signal for controlling the motor 62 and is output from the blow control unit 55 to the motor 62. The blower fan 65 is provided in the blower sharing area (2) and blows air between the paper P on which an image is formed and the fixing paper discharge roller.

  The motor 63 is connected to the blower fan 66, and drives the blower fan 66 at a predetermined rotational speed based on the motor drive signal S63. The motor drive signal S63 is a signal for controlling the motor 63, and is output from the blow control unit 55 to the motor 63. The blower fan 66 is provided in the blower sharing area (3) and blows air between the paper P on which the image is formed and the fixing paper discharge roller. As a result, the blower fan control unit 15 capable of controlling the separation air volume according to the rotational speed of the blower fans 64 to 66 can be configured.

Here, with reference to FIG. 3, the setting example (the 1) of the determination area | region of three ventilation division | segmentation area | regions (1)-(3) and printing rate [%] is demonstrated. According to the setting example of the determination area of the printing rate [%] shown in FIG. 3, the paper P is plain paper, the basis weight is 120 g / m ² or more, the paper P is coated paper, and the basis weight is 100 g / m. Applies to the case of ² or more.

  In this example, eight determination areas for determining the printing rate [%] are set in the three air-blowing sharing areas (1) to (3). For example, the full width of the air distribution areas (1) to (3) and the full width of the determination areas “1 to 8” are set equal to the printable width w. The width of one determination area is a length obtained by dividing the printable width w into 1/8.

  In order to cover the printable width w, three blower fans 64 to 66 are arranged in the three blower assignment areas (1) to (3). The blower sharing area (1) is provided with a blower fan 64, and two determination areas “1, 2” are set. The width of the ventilation sharing area (1) is equal to the width of the determination area “1, 2”. The blower sharing area (2) is provided with a blower fan 65, and four determination areas “3, 4, 5, 6” are set. The width of the air distribution area (2) is equal to the width of the determination area “3, 4, 5, 6”.

  The blower sharing area (3) is provided with a blower fan 66, and two determination areas “7, 8” are set. The width of the air distribution area (3) is equal to the width of the determination area “7, 8”. Compared with the determination area “3, 4, 5, 6” of the air distribution area (2), the determination areas of the air distribution area (1), (3) are less as “1, 2” and “7.8”. This is because the end of the paper P is often not printed. As a result, eight determination areas “1, 2, 3, 4, 5, 6, 7, 8” for determining the printing rate [%] are set in the three air distribution areas (1) to (3). become able to.

  Next, an example of storing the set value of the air volume [%] corresponding to the printing rate [%] will be described with reference to FIGS. 4A and 4B. The setting value of the appropriate air volume for the printing rate [%] shown in FIGS. 4A and 4B is stored as a reference table in the ROM 56 shown in FIG. 2, for example. The ROM 56 adopts a format in which the set value of the air volume [%] is read with the range of the printing rate [%] as an address.

  This storage example is a case where the paper P on which the image is formed has high (good) separability with respect to the fixing paper discharge roller or the like, and the air volume is in the range of the printing rate [%] from 0 to 10%. A set value of 10% is stored. When the range of the printing rate [%] is 11 to 30%, the set value of the air volume 20% is stored. When the printing rate [%] is in the range of 31 to 50%, the set value of the air volume 40% is stored. For the printing rate [%] range of 51 to 80%, the set value of the air volume 60% is stored. For the printing rate [%] range of 81 to 100%, the set value of the air volume 80% is stored.

  On the other hand, when the paper P on which the image is formed is low (poor) in separation performance with respect to the fixing paper discharge roller or the like, the setting value of the air volume [%] with respect to the printing rate [%] is shown in FIG. 4B. ing. In FIG. 4B, the set value of 10% of air volume is stored for the range of the printing rate [%] from 0 to 10%. When the range of the printing rate [%] is 11 to 30%, the set value of the air volume 30% is stored.

  For the printing rate [%] range of 31 to 50%, the set value of the air volume 60% is stored. For the range of the printing rate [%] of 51 to 80%, the set value of the air volume 80% is stored. For a printing rate [%] range of 81 to 100%, a setting value of 100% of air volume is stored. The set values of these two types of airflow [%] are applied to the three blower fans 64 to 66, and the blower control is executed.

  Next, an example of data storage before and after extracting the maximum printing rate [%] will be described with reference to FIGS. 5A and 5B. The data storage example shown in FIG. 5A is when the paper P on which the image is formed has good (high) separability with respect to the fixing paper discharge roller or the like, and the three blower sharing areas (1) to (3). Is a memory development image before extraction of the maximum printing rate [%] for the eight discriminating areas “1 to 8” in FIG.

  This memory expanded image is expanded in the memory unit 51, for example. According to the memory development image before the extraction of the maximum printing rate [%], eight determination areas “1 to 8” are provided for the three blower assignment areas (1) to (3). For these eight discriminating areas “1 to 8”, a data description column for each of the printing rate [%] [%] and the air volume [%] is provided. In the figure, the data description column is shown as blank.

  The data storage example shown in FIG. 5B is the above-described example, and is the case where the separability is good (high), and is the maximum for the eight discriminating areas “1-8” in the three air-sharing areas (1) to (3). It is a memory development image after extracting the printing rate [%] and setting the air volume [%].

  According to the data storage example after extraction of the maximum printing rate [%] and at the time of setting the air volume [%], first, in the ventilation sharing region (1), the printing rate 5 [%] in the determination region “1”. And a printing rate of 7 [%] is described in the determination area “2”. Since the maximum printing rate (indicated by the satin in the drawing) in the air distribution area (1) is 7 [%], the set value of the air volume 0 [%] is set based on FIG. 4A. The set value of the air volume 0 [%] means that the state where the blower fan 64 is stopped is maintained.

  Further, in the blower sharing area (2), the printing area 20 [%] is described in the determination area “3”, and the printing area 28 [%] is described in the determination area “4”. The print rate 38 [%] is described in the determination region “5”, and the print rate 35 [%] is described in the determination region “6”. Since the maximum printing rate (indicated by a satin in the drawing) in the air distribution area (2) is 38 [%], the set value of the air volume 40 [%] is set based on FIG. 4A. The set value of the air volume 40 [%] means that air is blown while maintaining the rotation speed of the blower fan 65 at 40 [%].

  Further, in the air distribution area (3), the printing area 9 [%] is described in the determination area “7”, and the printing area 5 [%] is described in the determination area “8”. Since the maximum printing rate (indicated by a satin in the drawing) in the air distribution area (3) is 9 [%], the set value of the air volume 0 [%] is set based on FIG. 4A. The blower fan 66 is stopped by the set value of the air volume 0 [%].

Here, with reference to FIG. 6, the setting example (the 2) of the determination area | region of three ventilation distribution areas (1)-(3) and a printing rate [%] is demonstrated. In this example, the air volume setting unit 54 switches the length of the determination area in the paper conveyance direction that is handled as an area for calculating the printing rate [%] according to the type and basis weight of the paper P. According to the setting example of the determination area of the printing rate [%] shown in FIG. 6, the paper P is plain paper, the basis weight is less than 120 g / m ² , the paper P is coated paper, and the basis weight is 100 g / m. Applies to cases where it is less than ² .

  In this example as well, eight determination areas for determining the printing rate [%] are set in the three air distribution areas (1) to (3). However, the determination areas in one row described in FIG. Switch to two rows. Also in this example, the full width of the air distribution areas (1) to (3) and the full width of the determination areas “1 to 8” are set equal to the printable width w. The width of one determination area is also a length obtained by dividing the printable width w into 1/8. However, two rows A and B of the determination area “1-8” are set continuously in the paper conveyance direction. Is done.

  In order to cover the printable width w, three blower fans 64 to 66 are arranged in the three blower assignment areas (1) to (3). The blower sharing area (1) is provided with a blower fan 64, and four determination areas “1A, 2A, 1B, 2B” in two rows A and B are set. The width of the air distribution area (1) is equal to the width of “1A, 2A” in the determination area A and “1B, 2B” in the determination area B.

  The blower sharing area (2) is provided with a blower fan 65, and eight determination areas “3A, 4A, 5A, 6A, 3B, 4B, 5B, and 6B” in two rows A and B are set. The width of the air distribution area (2) is equal to the width of “3A, 4A, 5A, 6A” in the determination area A and “3B, 4B, 5B, 6B” in the determination area B.

  The blower sharing area (3) is provided with a blower fan 66, and four determination areas “7A, 8A, 7B, 8B” in two rows A and B are set. The width of the air distribution area (3) is equal to the width of the determination area A “7A, 8A” and the determination area B “7B, 8B”.

  Compared with the determination area “3A, 4A, 5A, 6A, 3B, 4B, 5B, 6B” of the ventilation sharing area (2), the determination area of the ventilation sharing area (1), (3) is “1A, 2A, 1B, The reason why the numbers “2B” and “7A, 8A, 7B, 8B” are small is that the end of the paper P is often not printed. As a result, 8 × 2 rows of determination areas “1A to 8A, 1B to 8B” for determining the printing rate [%] can be set in the three air-blowing assignment areas (1) to (3).

  Next, an example of data storage before and after extracting the maximum printing rate [%] will be described with reference to FIGS. 7A and 7B. The data storage example shown in FIG. 7A is when the paper P on which the image is formed is low (bad) in separability with respect to the fixing paper discharge roller or the like, and is divided into three air-blowing sharing areas (1) to (3). 4 is a memory development image before extraction of the maximum printing rate [%] for the discrimination areas “1A to 8A, 1B to 8B” of 8 × 2 columns of A and B in FIG.

  This memory development image is also developed in the memory unit 51. According to the memory development image before extraction of the maximum printing rate [%], A and B for the discriminating areas “1 to 8” in one row with respect to the three air-sharing areas (1) to (3) The data description columns for the two rows of print ratio [%] and the air volume [%] of one row are provided. In the figure, the data description column is shown as blank.

  The data storage example shown in FIG. 7B is the above-described example, and is a case where the separability is low (bad), and the 8 × 2 columns of discrimination areas “1A to 8A in the three blower assignment areas (1) to (3)”. , 1B to 8B "after extracting the maximum printing rate [%] and setting the air volume [%].

  According to the data storage example after extraction of the maximum printing rate [%] and at the time of setting the air flow [%], first, in the ventilation sharing area (1), the printing rate 5 in the column A of the determination area “1”. [%] Is described, and the printing rate 12 [%] is described in the B column. The printing rate 7 [%] is described in the A column of the determination area “2”, and the printing rate 9 [%] is described in the B column.

  Since the maximum printing rate (indicated by a satin in the drawing) in the air distribution area (1) is 12 [%], the set value of the air volume 30 [%] is set based on FIG. 4B. The set value of the air volume 30 [%] is set so as to blow with the rotation speed of the blower fan 64 being 30%.

Further, in the ventilation sharing area (2), the printing rate 20 [%] is described in the A column of the determination area “3”, and the printing rate 15 [%] is described in the B column. The printing rate 28 [%] is described in the A column of the determination area “4”, and the printing rate 53 [%] is described in the B column. The print rate 38 [%] is described in the A column of the determination area “5”, and the print rate 53 [%] is described in the B column.
The print rate 35 [%] is described in the A column of the determination area “6”, and the print rate 35 [%] is described in the B column.

  Since the maximum printing rate (indicated by a satin in the drawing) in the air distribution area (2) is 53 [%], the set value of the air volume 80 [%] is set based on FIG. 4B. The set value of the air volume 80 [%] is set so as to blow with the rotational speed of the blower fan 65 being 80 [%].

  Further, in the blower sharing area (3), the printing rate 9 [%] is described in the A column of the determination area “7”, and the printing rate 3 [%] is described in the B column. The printing rate 5 [%] is described in the A column of the determination area “8”, and the printing rate 0 [%] is described in the B column. Since the maximum printing rate (indicated by a satin in the drawing) in the air distribution area (3) is 9 [%], the set value of the air volume 10 [%] is set based on FIG. 4B. According to the set value of the air volume 10 [%], the blower fan 66 is blown with the rotational speed of 10 [%].

  Next, with reference to FIG. 8, a description will be given of a setting example (No. 3) of the three air distribution areas (1) to (3) and the determination area of the printing rate [%]. In this example, according to the type and basis weight of the paper P, the air volume setting unit 54 switches from “8” to “16” as the number of divisions in the determination area in the paper width direction that is treated as an area for calculating the printing rate [%]. I did it. In the example described with reference to FIGS. 3 to 7, the number of divisions in the paper width direction orthogonal (perpendicular) to the paper conveyance direction is “8” as a standard. On the other hand, the number of divisions is increased according to the paper type and basis weight of the paper P.

In this example, when the paper P is plain paper and the basis weight is less than 70 g / m ² , it is determined that the separability is extremely low. Compared to the example described with reference to FIGS. 3 to 7, the number of divisions of the discrimination region in the paper width direction is set to “16” which is double.

  In the three blower assignment areas (1) to (3) shown in FIG. 8, the two rows of determination areas described in FIG. 6 are doubled, and 16 determinations for determining the printing rate [%]. An area is set. Also in this example, the full width of the air distribution areas (1) to (3) and the full width of the determination areas “1 to 16” are set to be equal to the printable width w. The width of one determination area is a length obtained by dividing the printable width w by 1/16. Two rows A and B of the determination area “1 to 16” are set continuously in the paper conveyance direction. The

  In order to cover the printable width w, three blower fans 64 to 66 are arranged in the three blower assignment areas (1) to (3). The blower sharing area (1) is provided with a blower fan 64, and eight determination areas “1A, 2A, 3A, 4A, 1B, 2B, 3B, 4B” in two rows A and B are set. The width of the air distribution area (1) is equal to the width of “1A, 2A, 3A, 4A” of the determination area A, “1B, 2B, 3B, 4B” of the determination area B, or the like.

  The blower sharing area (2) is provided with a blower fan 65, and 16 determination areas “5A, 6A, 7A, 8A, 9A, 10A, 11A, 12A, 5B, 6B, and 7B in two rows A and B”. , 8B, 9B, 10B, 11B, 12B "are set. The width of the air blowing area (2) is “5A, 6A, 7A, 8A, 9A, 10A, 11A, 12A” in the determination area A and “5B, 6B, 7B, 8B, 9B, 10B, 11B” in the determination area B. , 12B ".

The blower sharing area (3) is provided with a blower fan 66, and eight determination areas “13A, 14A, 15A, 16A, 13B, 14B, 15B, 16B” in two rows A and B are set.
The width of the air distribution area (3) is equal to the width of the determination area A “13A, 14A, 15A, 16A” and the determination area B “13B, 14B, 15B, 16B”.

  Compared with the determination area “5A, 6A, 7A, 8A, 9A, 10A, 11A, 12A, 5B, 6B, 7B, 8B, 9B, 10B, 11B, 12B” of the air distribution area (2) ), (3) has a small determination area of “1A, 2A, 3A, 4A, 1B, 2B, 3B, 4B” and “13A, 14A, 15A, 16A, 13B, 14B, 15B, 16B”. This is because the end of P is often not printed. As a result, 16 × 2 determination areas for determining the printing rate [%] can be set in the three air distribution areas (1) to (3).

  Next, an example of data storage before and after extracting the maximum printing rate [%] will be described with reference to FIGS. 9A and 9B. The data storage example shown in FIG. 9A is a case where the paper P on which an image is formed is low (bad) in separability with respect to the fixing paper discharge roller or the like, and is divided into three blower sharing areas (1) to (3). 4 is a memory development image before extraction of the maximum printing rate [%] for the discrimination areas “1A to 16A, 1B to 16B” of 16 × 2 columns of A and B in FIG.

  This memory development image is also developed in the memory unit 51. According to the memory development image before the extraction of the maximum printing rate [%], A and B for the discriminating areas “1 to 16” in one row with respect to the three air distribution areas (1) to (3) The data description columns for the two rows of print ratio [%] and the air volume [%] of one row are provided. In the figure, the data description column is shown as blank.

  The data storage example shown in FIG. 9B is the above-mentioned example, and is a case where the separability is low (bad), and the 16 × 2 column discrimination areas “1A to 16A in the three air-blowing sharing areas (1) to (3)”. , 1B to 16B ”after extracting the maximum printing rate [%] and setting the air volume [%].

  According to the data storage example after extraction of the maximum printing rate [%] and at the time of setting the air volume [%], first, in the ventilation sharing area (1), the printing rate is 0 in the A column of the determination area “1”. [%] Is described, and the printing rate 0 [%] is described in the B column. The print rate 10 [%] is described in the A column of the determination area “2”, and the print rate 24 [%] is described in the B column. The printing rate 6 [%] is described in the A column of the determination area “3”, and the printing rate 11 [%] is described in the B column.

  The print rate 8 [%] is described in the A column of the determination area “4”, and the print rate 7 [%] is described in the B column. Since the maximum printing rate (indicated by a satin in the drawing) in the air distribution area (1) is 24 [%], the set value of the air volume 30 [%] is set based on FIG. 4B. The set value of the air volume 30 [%] is set so as to blow with the rotation speed of the blower fan 64 being 30%.

Further, in the blower sharing area (2), the printing rate 15 [%] is described in the A column of the determination area “5”, and the printing rate 12 [%] is described in the B column. The printing rate 25 [%] is described in the A column of the determination area “6”, and the printing rate 18 [%] is described in the B column. The print rate 26 [%] is described in the A column of the determination area “7”, and the print rate 40 [%] is described in the B column.
The printing rate 30 [%] is described in the A column of the determination area “8”, and the printing rate 66 [%] is described in the B column.

  The print rate 34 [%] is described in the A column of the determination area “9”, and the print rate 60 [%] is described in the B column. The print rate 42 [%] is described in the A column of the determination area “10”, and the print rate 46 [%] is described in the B column. The print rate 43 [%] is described in the A column of the determination area “11”, and the print rate 42 [%] is described in the B column. The printing rate 27 [%] is described in the A column of the determination area “12”, and the printing rate 28 [%] is described in the B column. Since the maximum printing rate (indicated by the satin in the drawing) in the air distribution area (2) is 66 [%], the set value of the air volume 80 [%] is set based on FIG. 4B. The set value of the air volume 80 [%] is set so as to blow with the rotational speed of the blower fan 65 being 80 [%].

  Further, in the air distribution area (3), the printing rate 16 [%] is described in the A column of the determination area “13”, and the printing rate 6 [%] is described in the B column. The print rate 2 [%] is described in the A column of the determination area “14”, and the print rate 0 [%] is described in the B column. The print rate 2 [%] is described in the A column of the determination area “15”, and the print rate 0 [%] is described in the B column. The print rate 0 [%] is described in the A column of the determination area “16”, and the print rate 0 [%] is described in the B column.

  Since the maximum printing rate (indicated by the satin in the drawing) in the air distribution area (3) is 16 [%], the set value of the air volume 30 [%] is set based on FIG. 4B. According to the set value of the air volume 30 [%], the blower fan 66 is blown with the rotational speed of 30 [%].

  Next, an example of air flow control based on the maximum image printing rate [%] in the blower fan control unit 15 will be described with reference to FIG. 10 regarding the control method of the image forming apparatus according to the present invention. In this embodiment, the air volume setting unit 54 switches the setting of the air volume [%] corresponding to the printing rate [%] according to the type and basis weight of the paper P. In this example, the following criteria are provided for setting the air volume [%] of the blower fans 64 to 66.

According to this criterion, when the paper type of the paper P is plain paper and the basis weight is less than 120 g / m ^2, or the paper type is coated paper and the basis weight is less than 100 g / m ² Judge that the separability is low. As a result of this determination, the paper P having low separability is determined in two rows, and in other cases, one row of determination areas is set to determine the air volume [%]. The blower control unit 55 sets a plurality of blower sharing areas (1) to (3) for the leading end area of the paper P, sets the air volume [%], and sets the air volume [%]. An example of controlling the blower fans 64 to 66 by controlling the blower fan driving motors 61 to 63 will be described as an example.

  Under these control conditions, in the blower fan control unit 15, the memory unit 51 inputs the image data DIN in step ST1 shown in FIG. 10 in order to determine whether or not the separation property of the paper P is low. The memory unit 51 stores image data DIN for each page from an image memory (not shown) or the like.

In step ST2, the blower fan control unit 15 branches the control depending on whether the paper type of the paper P is coated paper and the basis weight is less than 100 g / m ² . Information such as the paper type and the basis weight of the paper P is acquired from a job management memory or the like that manages the image data DIN in units of pages. Operation data indicating image forming conditions set on the operation display panel 48 is stored in the job management memory.

When the paper P is coated paper and the basis weight is 100 g / m ² or more, the process proceeds to step ST3, and the blower fan control unit 15 further determines that the paper P is a plain paper, and Control branches depending on whether the basis weight is less than 120 g / m ² . When the paper P is plain paper and the basis weight is 120 g / m ² or more, the process proceeds to step ST4, and in the blower fan control unit 15, the region setting unit 52 sets the determination region to “one row”. At this time, as shown in FIG. 3, the area setting unit 52 includes eight determination areas “1, 2, 3” for determining the printing rate [%] in the three air-sharing areas (1) to (3). , 4, 5, 6, 7, 8 ". Thereafter, the process proceeds to step ST7.

When the paper P is coated paper and has a basis weight of less than 100 g / m ^{2 in the} above-mentioned step ST2,
When the paper P is coated paper and has a basis weight of less than 120 g / m ² in step ST3 described above, the process proceeds to step ST5, and the area setting unit 52 sets the determination area to “two rows”. At this time, as shown in FIG. 6, the area setting unit 52 determines 8 × 2 rows A and B for determining the printing rate [%] in the three air-sharing areas (1) to (3). Regions “1A-8A, 1B-8B” are set.

Thereafter, the process proceeds to step ST6, and the blower fan control unit 15 branches the control depending on whether the paper P is plain paper and has a basis weight of less than 70 g / m ² . When the paper P is plain paper and has a basis weight of 70 g / m ² or more, the process proceeds to step ST7, and in the blower fan control unit 15, the area setting unit 52 sets the number of vertical divisions in the paper width direction of the determination area to “8”. Set. At this time, the area setting unit 52 divides the three air distribution areas (1) to (3) controlled by the air blowing control unit 55 into eight, and sets eight determination areas “1 to 8”. It becomes like this. Thereafter, the process proceeds to step ST9.

When the paper P is plain paper and the basis weight is less than 70 g / m ² in step ST6 described above, the process proceeds to step ST8 and the blower fan control unit 15 determines that the area setting unit 52 determines the paper width of the determination area. The number of vertical divisions in the direction is set to “16”. At this time, as shown in FIG. 8, the region setting unit 52 divides the three air-blowing sharing regions (1) to (3) controlled by the air-blowing control unit 55 into 16 pieces and determines 32 determination regions. “1A to 16A, 1B to 16B” is set.

  Thereafter, the process proceeds to step ST9, and in the blower fan control unit 15, the printing rate calculation unit 53 calculates the printing rate [%] of each region. At this time, the printing rate calculation unit 53 inputs density information of an image formed in the leading end region of the paper P, and sets a plurality of air distribution regions (1) to (3) divided by the region setting unit. For each determination area, the printing rate [%] based on the image density information is calculated.

  At this time, the printing rate calculation unit 53 inputs density information of the image formed in the leading end region of the paper P from the memory unit 51, and supplies the density distribution regions (1) to (3) divided by the region setting unit 52. The printing rate [%] based on the density information of the image is calculated for each of the eight determination areas “1 to 8” and 16 determination areas “1 to 16” for A and B. The printing rate [%] is calculated by setting the maximum density Dmax at which the toner adhesion amount is maximum to 100%, and the density of the image is calculated as a ratio to the maximum density Dmax.

  Thereafter, in step ST10, the blower fan control unit 15 extracts the maximum printing rate [%] for each of the blower fans 64-66. At this time, the maximum printing rate [%] in the delivery sharing areas (1) to (3) assigned corresponding to the blower fans 64 to 66 is extracted. In FIG. 5B, FIG. 7B, and FIG. 9B, the area | region where the maximum printing rate [%] is extracted in a memory expansion | deployment image is shown in the satin. The maximum printing rate [%] is extracted using the maximum value detection method. According to the maximum value detection method, all the print rates [%] to be detected are compared, and the largest print rate [%] (maximum value) is detected.

  In step ST <b> 11, in the blower fan control unit 15, the air volume setting unit 54 sets the air volume [%] corresponding to the maximum printing rate [%] in the blower control unit 55. At this time, the air volume setting unit 54 collates the maximum print rate [%] of each of the blower fans 64 to 66 with the set value of the air flow [%] with respect to the print rate [%] shown in FIGS. 4A and 4B. Determine the air flow [%]. The air blowing control unit 55 controls the air blowing fans 64 to 66 by controlling the air blowing fan driving motors 61 to 63 so that the air amount [%] determined (set) by the air amount setting unit 54 is obtained. The blower fans 64 to 66 blow air between the paper P on which an image is formed by the image forming unit 80 and the fixing paper discharge roller that conveys the paper P.

  As described above, according to the color copying machine 100 according to the first embodiment, the air volume setting unit 54 includes the eight determination areas “1 to 8” calculated by the printing rate calculation unit 53 and the sixteen A and B colors. The air volume [%] corresponding to the printing rate [%] of the determination areas “1 to 16” is set in the air blow control unit 55.

  When the print rate [%] of the image formed in the leading end region of the paper P is high by this air flow setting, a large air flow [%] is set, and when the print rate [%] is low, the air flow [%] is set. ] Can be set to a small value, so that even when there is a bias in the toner adhesion amount in the leading end region of the paper P, an appropriate separation air volume can be set in the blower section.

  Therefore, separation control between the fixed paper P and the fixing paper discharge roller can be performed with high accuracy. As a result, compared to the conventional method, it has become possible to improve in many aspects, such as an improvement in separability by blowing air, prevention of inflow of hot air, prevention of paper wrinkles, and reduction in power consumption, without unnecessarily increasing the number of air blowing units.

  According to the color copying machine 100, the air volume setting unit 54 sets the air volume [%] corresponding to the extracted maximum printing rate [%] in the blower control unit 55, so that the printing rate [%] is set to a determination region where the printing rate [%] is low. Compared to this, it is now possible to set more air volume [%] in the discrimination area where the printing rate [%] is high.

  According to the color copying machine 100, the fan is provided in the air blowing unit, and the air blowing control unit 55 controls the air volume [%] by the rotation speed of the fan. Compared to P, the air volume [%] for plain paper with a small basis weight (light) can be set very finely.

  According to the color copying machine 100, since the air volume setting unit 54 switches the setting of the air volume [%] according to the printing rate [%] according to the type and basis weight of the paper P, it is difficult to wind the paper around the fixing paper discharge roller. Compared to the paper P of seed and basis weight, it is possible to set a larger air volume [%] for plain paper having a small basis weight (light).

  According to the color copying machine 100, the air volume setting unit 54 switches the length of the determination area in the paper conveyance direction that is treated as the area for calculating the printing rate [%] according to the type and basis weight of the paper P. Compared with paper P having a paper type and basis weight that is difficult to wind around a paper roller or the like, the length of the determination region in the paper conveyance direction of plain paper having a small basis weight (light) can be expanded. As a result, it has become possible to set a large air volume [%] for plain paper with a small basis weight (light).

  According to the color copying machine 100, the air volume setting unit 54 switches the number of divisions of the determination area in the paper width direction that is treated as the area for calculating the printing rate [%] according to the type and basis weight of the paper P. The number of divisions of the determination area in the paper width direction such as plain paper having a small basis weight (light) can be set as compared with the paper P having a paper type and a basis weight that is difficult to wind around a paper roller or the like. As a result, it has become possible to set a large air volume [%] for plain paper with a small basis weight (light).

  Next, a configuration example of the shutter mechanism 70 as the second embodiment will be described. FIG. The shutter mechanism 70 shown in FIG. 11 constitutes another example of the blower unit, and includes a motor 67 for driving the blower fan, a blower fan 68, and a shutter main body 76. A blower control unit 55 ′ is connected to the shutter mechanism 70. The blower control unit 55 ′ is provided in place of the blower control unit 55 in the blower fan control unit 15 of the color copying machine 100 according to the first embodiment.

  The motor 67 is connected to a blower fan 68 that constitutes an example of the blower unit, and drives the blower fan 68 at a predetermined rotational speed based on the motor drive signal S67. The motor drive signal S67 is a signal for controlling the motor 67, and is output from the blow control unit 55 'to the motor 67.

  The air blow control unit 55 'is connected to the air volume setting unit 54 described in the first embodiment. The air blow control unit 55 ′ receives the air volume setting information D 54 from the air volume setting unit 54, and generates three shutter control signals S 71 to S 73 based on the set value of the air volume [%]. The shutter control signal S71 is a signal for setting the air volume [%] of the air to be blown to the air blowing area (1) as described in the first embodiment. Similarly, the shutter control signal S72 is a signal for setting the air volume [%] of the air to be blown to the air blowing area (2). Similarly, the shutter control signal S73 is a signal for setting the air volume [%] of the air to be blown to the air blowing area (3).

  In this example, the blower fan 68 has a blowout port 608. One end of a blower duct 77 is connected to the blowout port 608 of the blower fan 68, and the shutter main body 76 is connected to the other end. The blower duct 77 guides the air blown from the blower fan 68 to the shutter main body 76.

  The shutter main body 76 has a reverse hopper shape and has a shape that expands in a fan shape in the paper width direction w ′. The shutter main body 76 has an air intake port 704 that is substantially equal to the opening diameter of the blowout port 608 and a blowout port 705 that is substantially equal to the paper width direction w ′.

  The shutter main body 76 includes three shielding plates 71 to 73, three solenoid members 701 to 703, and two air blowing guide plates 74 and 75. The inside of the shutter main body 76 is partitioned by two blowing guide plates 74 and 75 at the blowout port 705 so as to form the blowing sharing areas (1) to (3).

  The air guide plate 74 extends radially from the air intake port 704 of the shutter main body 76 toward the air outlet 705 toward the left end portion thereof, and is disposed at a position that divides the air distribution areas (1) and (2). Is done. The air guide plate 75 extends radially from the air intake port 704 of the shutter main body 76 toward the air outlet 705 toward the right end side thereof, and is arranged at a position that divides the air distribution areas (2) and (3). Established.

  The shielding plate 71 and the solenoid member 701 are provided at predetermined positions between the left inclined side wall portion of the shutter main body portion 76 and the air blowing guide plate 74. The shielding plate 71 is controlled to be opened and closed by a solenoid member 701. The solenoid member 701 operates to vary the degree of opening and closing of the shielding plate 71 based on the shutter control signal S71. The shielding plate 72 is provided between the air guide plate 74 and the air guide plate 75 of the shutter main body 76 and is controlled to be opened and closed by a solenoid member 702. The solenoid member 702 operates so as to vary the degree of opening and closing of the shielding plate 72 based on the shutter control signal S72.

  The shielding plate 73 is provided between the air blowing guide plate 75 and the inclined right side wall portion of the shutter main body portion 76 and is controlled to be opened and closed by a solenoid member 703. The solenoid member 703 operates so as to vary the degree of opening and closing of the shielding plate 73 based on the shutter control signal S73.

  In the second embodiment, when the color printer 80 forms an image on the paper P, the shutter mechanism 70 moves between the paper P on which the image has been formed by the color printer 80 and the fixing paper discharge roller 17a that conveys the paper P. To blow. The air blowing control unit 55 ′ sets a plurality of air blowing areas (1) to (3) for the leading end area of the paper P, sets the air volume [%], and becomes the set air volume [%]. In this manner, the shutter mechanism 70 is controlled to blow.

  The area setting unit 52 divides the air distribution areas (1) to (3) controlled by the air flow control unit 55 ′ into 8 or 16, and the determination areas “1 to 8” and “1 to 1”. 16 "etc. are set. The printing rate calculation unit 53 inputs density information of an image formed in the leading end region of the paper P, and the determination region “1” set in the air sharing regions (1) to (3) divided by the region setting unit 52. Print rate [%] based on image density information is calculated for each of “˜8” and “1-16”. Based on these assumptions, the air volume setting unit 54 blows the air volume [%] corresponding to the determination area “1-8” calculated by the printing rate calculation unit 53 and the printing rate [%] of “1-16”. The control unit 55 'is set.

  As described above, according to the color copying machine 100 according to the second embodiment, the shutter main body 76 is provided with the shutter mechanism 70 having the shielding plates 71 to 73, and the air blowing control unit 55 ′ is provided with the air volume setting unit 54. Since the air volume [%] is controlled by the degree of opening and closing of the shielding plates 71 to 73 corresponding to the printing rate [%] set by, the paper type and the basis weight of the paper P that is difficult to wind around the fixing paper discharge roller 17a, The air volume [%] for plain paper with a small basis weight (light) can be set instantly.

  Moreover, in the same way as in the first embodiment, the air volume setting unit 54 sets the air volume [%] to be increased when the printing rate [%] of the image formed in the leading edge region of the paper P is high. When the printing rate [%] is low, the air volume [%] can be set to be small. Therefore, even when the amount of toner adhering to the leading edge area of the paper is uneven, an appropriate separation air volume can be set. The shutter mechanism 70 can be set.

  Accordingly, the separation control between the fixed paper P and the fixing paper discharge roller 17a can be executed with high accuracy. Thereby, compared with the conventional system, it becomes possible to improve in many aspects, such as an improvement in separability by blowing air, prevention of inflow of hot air, prevention of paper wrinkles, and reduction of power consumption, without unnecessarily increasing the number of air blowing units.

  In the second embodiment, the case where the shutter mechanism 70 is provided for the blower unit has been described. However, the present invention is not limited to this. For example, instead of the shutter mechanism 70, a not-shown pressurizing pump, a blowing nozzle, and a blower control unit for the pressurizing pump are provided, and the air volume [%] is controlled by the pressure applied at the time of injection of the pressurizing pump. You may make it do. Even with this pressure control, the air flow [%] to plain paper having a smaller basis weight (lighter) than the paper P having a paper type and a basis weight that is difficult to be wound around the fixing paper discharge roller 17a is instantaneously set to control the air flow. Can be executed.

  The present invention is applied to color, black and white printers, copiers, and multifunction devices having a function of blowing air between a sheet on which an image is formed and a fixing discharge roller that conveys the sheet. Therefore, it is very suitable.

DESCRIPTION OF SYMBOLS 15 Air blow control part 17 Fixing device 17a Fixing discharge roller 20 Paper supply part 21-23, 201,202 Paper feed tray 25 Paper discharge tray 48 Operation display panel 51 Memory part 52 Area setting part 53 Print rate calculation part 54 Air volume setting part 55, 55 ', 75 Air blow control unit 56 ROM
61, 62, 63 Motor (blower)
64-66 Blower fan (Blower part)
70 Shutter mechanism (air blower)
71-73 Shielding plate 74,75 Blower guide plate 80 Color printer (image forming unit)
100 color copier (image forming device)
DESCRIPTION OF SYMBOLS 101 Copier main body part 102 Scanner 200 Large paper feeder 701-703 Solenoid member (blowing part)

Claims (11)

An image forming apparatus comprising: an image forming unit; and a blowing unit that blows air between a sheet on which an image is formed by the image forming unit and a sheet conveying unit that conveys the sheet.
A blower control unit that sets a plurality of blower sharing areas with respect to the front end region of the paper, sets a flow rate, and blows the blower unit so as to achieve the set flow rate;
An area setting unit that sets the plurality of determination areas by dividing the air distribution area that is controlled by the air flow control unit into two or more;
The printing rate based on the density information of the image is input for each of the plurality of determination areas set in the ventilation sharing area divided by the area setting unit by inputting density information of the image formed in the leading edge area of the paper A printing rate calculation unit for calculating
An image forming apparatus comprising: an air volume setting unit that sets an air volume corresponding to the print rates of the plurality of determination areas calculated by the print rate calculating unit in the air blowing control unit. The air volume setting unit
Extracting a maximum printing rate for each of the air-blowing shared areas from the printing rates of the plurality of determination areas calculated by the printing rate calculating unit, and setting an air volume corresponding to the maximum printing rate in the air blowing control unit. The image forming apparatus according to claim 1. The air volume setting unit
The image forming apparatus according to claim 1, wherein the setting of the air volume according to the printing rate is switched according to the type and basis weight of the paper. The air volume setting unit
The image forming apparatus according to claim 1, wherein the length of the determination area in the paper conveyance direction handled as the area for calculating the printing rate is switched according to the type and basis weight of the paper. The air volume setting unit
The image forming apparatus according to claim 1, wherein the number of divisions of the determination area in the paper width direction handled as the area for calculating the printing rate is switched according to the type and basis weight of the paper. A fan is provided in the blowing section,
The air blowing control unit
The image forming apparatus according to claim 1, wherein the air volume is controlled by the rotational speed of the fan. A shutter having a shielding plate is provided in the air blowing part,
The air blowing control unit
The image forming apparatus according to claim 1, wherein the air volume is controlled by an opening / closing degree of the shielding plate. A pressure pump is provided in the blowing section,
The air blowing control unit
The image forming apparatus according to claim 1, wherein the air volume is controlled by pressure applied at the time of injection of the pressurizing pump. An image forming apparatus including a sheet on which an image is formed and a blowing unit that blows air between a sheet conveying unit that conveys the sheet.
Setting a plurality of air-sharing areas with respect to the leading edge area of the paper, setting an air volume, and controlling the air flow of the air-blowing unit so that the air volume is set;
Dividing the air blowing area to be blown into two or more and setting a plurality of determination areas; and
Inputting density information of an image formed in the leading edge region of the paper;
Calculating a printing rate based on the density information of the image for each of the plurality of determination areas set in the divided air distribution area;
And a step of setting the air volume corresponding to the calculated printing rates of the plurality of determination areas in the blower unit. A program for controlling an image forming apparatus including a sheet on which an image is formed and a blowing unit that blows air between a sheet conveying unit that conveys the sheet,
10. A computer-readable program that is a program capable of executing the control method for an image forming apparatus according to claim 9. A recording medium on which a program for controlling an image forming apparatus including a paper on which an image is formed and a blower that blows air between a paper transport unit that transports the paper is described.
A recording medium in which a computer-readable program for executing the control method for an image forming apparatus according to claim 9 is described.

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