JP2007136847A - Image forming apparatus and method for controlling driving of mist suction fan - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To silence noise when a suction fan is driven. <P>SOLUTION: A controlling device 30 is equipped with a recording controlling part 31 which controls the printing operation to a recording medium of image data, a delivering amount calculating part 33 which calculates an ink delivering amount when printing is carried out, a mist suction fan controlling part 35 which controls rotational driving of the mist suction fan 43, and a mist suction fan controlling signal generating part 34 which generates a control signal of the mist suction fan control part 35. The mist suction fan control signal generating part 34 generates the control signal on the basis of the ink delivering amount calculated by the delivering amount calculating part 33. The mist suction fan controlling part 35 controls a rotating state of the suction fan on the basis of the generated control signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that records an image by ejecting ink onto a recording medium from a recording head having a plurality of ink ejection nozzles based on image data, and more specifically, the image forming apparatus floats in air during printing. The present invention relates to control of a suction fan that sucks ink.

  2. Description of the Related Art Image forming apparatuses such as printers and plotters used as recording apparatuses such as copying machines and facsimile machines, or output devices such as computers, workstations, and word processors use images (characters and symbols) on recording media such as paper based on image information. Is included). As such an image forming apparatus, there are an ink jet type, a wire dot type, a thermal type, a thermal transfer type, a laser beam type and the like depending on a recording method.

  The image forming apparatus records an image (including characters and symbols) by ejecting ink onto a recording medium such as recording paper. As the image forming apparatus, among various image forming apparatuses, a serial type recording apparatus that employs a recording method in which main scanning is performed in a direction intersecting with the conveyance direction (sub-scanning direction) of the recording medium (recording medium), There is also known a recording apparatus that employs a recording method in which the recording medium is moved in the conveying direction with respect to recording means in which the nozzles are arranged in a line over the entire width of the recording medium.

  For example, in a serial type recording apparatus, when an image is formed on a recording medium, the recording medium size is detected by an optical sensor or the like, and then the recording medium being conveyed is temporarily stopped by the recording medium conveying apparatus. An image forming area on the recording medium facing the ink ejection port of the nozzle group by ejecting ink from the nozzle based on the image signal carrying the image information defined by the recording paper size while moving the image in a predetermined direction An image for one band is formed in (band region).

  Next, the recording medium is transported by the width of one band and stopped, and again, the carriage is reciprocated in the predetermined direction, and ink is ejected from the nozzle group based on the image signal to form an image on the recording medium. The entire image is formed in a new band area located in the area. By repeating such an operation, an image for one page is formed on the recording medium, and after the image for one page is formed, the trailing edge of the sheet is cut as necessary.

  Further, in a recording apparatus using a recording unit having a nozzle in which a plurality of nozzles are arranged in a line over the entire width of the recording medium, after the recording medium is set at a predetermined recording position, the recording unit is arranged in a line. An image is recorded on the recording medium by printing in a line and repeating the operation of printing in a line after feeding a predetermined amount of paper.

  When printing is performed by the ink jet recording apparatus, some of the ink ejected from the nozzles does not adhere to the output paper and floats in the air. Thus, the ink component that floats in the air during printing by ink ejection is called mist.

  If the mist is left without any treatment, the inside of the recording apparatus is contaminated by the mist. Also, if a large amount of mist adheres to the linear scale, which is a means for knowing the position information of the carriage unit, the linear scale sensor may erroneously detect and the carriage may malfunction.

  In order to prevent such contamination of the recording machine due to mist and malfunction of the carriage, the current product is provided with a suction fan for collecting mist. Before starting printing, the driving of the mist suction fan is turned on, and after the completion of printing, for example, a mist suction fan control is performed such that the driving is turned off after a predetermined time such as 1 minute has passed, Mist is sucked when ink is ejected.

  However, noise such as wind noise due to rotation of the fan is a problem when the suction fan is driven, and noise reduction is required when the suction fan is driven.

  Therefore, the present invention is to solve the above-described problems, and an object thereof is to reduce noise during driving of a suction fan.

  An image forming apparatus according to the present invention is an image forming apparatus that records an image by ejecting ink onto a recording medium from a recording head having a plurality of ink ejection nozzles based on the image data. The controller includes a control device that controls ejection, and a mist suction fan that sucks mist of ink floating in the air during printing. The control device determines the rotation state of the mist suction fan according to the amount of ink ejected during printing. Control.

  The inventor of the present application has found that the mist generated during printing does not necessarily occur in a certain amount during printing, but depends on the image data to be printed. In view of this viewpoint, the present invention reduces noise generated by driving the suction fan by controlling the mist suction fan.

  In the image forming apparatus of the present invention, as in the conventional control, the mist suction fan is controlled to be turned on / off between an off state (0% drive) in which the mist suction fan is stopped and an on state (100% drive) in which the suction fan is driven. Is based on the print density of the image data corresponding to the print density and the drive frequency of the head that performs printing by performing duty control between 0% and 100% by pulse width control (PWM control) Control the mist suction fan.

  With this duty control, when printing image data with a low printing duty, it is possible to suppress the rotation speed and driving time of the mist suction fan, and to suppress noise during driving of the mist suction fan. When printing image data with a low printing duty, since the amount of mist discharged is small, the mist can be sufficiently sucked even by the control for suppressing the rotation speed and driving time of the mist suction fan. The control device can reduce noise generated by driving the mist suction fan by controlling the mist suction fan in a rotation state corresponding to the ink discharge amount generated at the time of printing.

  The control device of the present invention includes a recording control unit that controls a printing operation of image data on a recording medium, a discharge amount calculation unit that calculates an ink discharge amount at the time of printing, and a mist suction unit that controls rotational driving of a mist suction fan. A fan control unit, and a mist suction fan control signal generation unit that generates a control signal of the mist suction fan control unit. The mist suction fan control signal generation unit generates a control signal based on the ink discharge amount calculated by the discharge amount calculation unit, and the mist suction fan control unit determines the rotation state of the mist suction fan based on the generated control signal. Control.

  The present invention finds that there is a linear relationship between the amount of ink discharged during printing and the number of dots during printing. Based on this relationship, the amount of ink discharged during printing is counted as the number of dots during printing. To calculate. The discharge amount calculation unit of the present invention includes dot counter means, and thereby calculates the ink discharge amount by counting the number of dots output from the recording control unit.

  The mist suction fan control signal generation unit includes a print duty calculation unit that calculates a print duty and a control signal generation unit that generates a control signal based on the calculated print duty. Here, the print duty is a ratio of the ink discharge amount when the image data is printed to the ink discharge amount when the nozzle of each color of the head is printed at 100%, and the print duty of the image data with respect to the maximum ink discharge amount. This represents the ratio of the amount of mist generated by printing. By generating the control signal based on the print duty, the mist suction fan is driven according to the ink discharge amount actually generated, and unnecessary high-speed rotation and long-time rotation are suppressed to reduce noise. be able to.

  The print duty calculating means obtains the ink discharge amount when all the nozzles of the head print at 100% by the product of the number of dots representing the data length of the image data and the number of nozzles of each head, and the dot counter means calculates it. The ink discharge amount when image data is printed is obtained from the sum of the number of dots of each head, and the print duty is calculated by dividing the obtained sum by the product.

  Further, the print duty calculation means obtains the ink discharge amount when the image data is printed by calculating the sum of values obtained by multiplying the number of dots of each color nozzle by a predetermined coefficient set for each nozzle and performing weighting. Also good. In this way, by weighting the number of dots of the nozzles of each color, it can be applied to the ink discharge amount characteristics from the nozzles. For example, if the ink discharge amount varies depending on the color, setting the weighting coefficient according to the discharge amount characteristic makes it possible to set the print duty smaller than when handling the number of dots uniformly, and to reduce noise. Further reduction can be achieved.

  The control signal generating means is a suction fan duty generating means for generating a mist suction fan duty for determining a PWM ratio of a drive signal for controlling the pulse width of the rotation speed of the mist suction fan, or a rotation for generating a rotation driving time of the mist suction fan. It can be set as a drive time production | generation means. The suction fan duty generation means can control the rotation speed of the mist suction fan, and the rotation drive time generation means can control the rotation drive time of the mist suction fan.

  Further, the mist suction fan control signal generating means of the present invention comprises parameter setting means for setting a parameter for determining the relationship of the control signal with respect to the print duty.

  The control signal generating means can generate a control signal for the print duty in accordance with the parameter set by the parameter setting means, and can change the print duty by changing the parameter.

  The parameter setting means can use a scanning speed for moving the head in the main scanning direction as a parameter. When the scan speed is used as a parameter, the suction fan duty generation unit generates a mist suction fan duty for the print duty according to the magnitude of the scan speed.

  For example, when the scan speed is high, the mist suction fan duty ratio with respect to the print duty is set to a large parameter, so that even when the print duty is small, the rotation speed of the mist suction fan is increased to suck the mist. Speed up to support high-speed scanning.

  When the scan speed is low, the mist suction fan duty ratio with respect to the print duty is set to a small parameter so that the rotation speed of the mist suction fan is compared with that during high-speed scan even when the print duty is large. To keep it low and to support low-speed scanning.

  In addition to the above, the parameter setting means can use the number of bands or the time width as a parameter. When the number of bands or the time width is used as a parameter, the suction fan duty generation unit changes the time width for generating the mist suction fan duty according to the number of bands or the time width.

  Here, the number of bands can be one band or a plurality of bands. The suction fan duty generation means generates a mist suction fan duty for each band printing or in units of a plurality of bands. Thereby, the drive control interval of the mist suction fan can be set in band units. For example, in the case of image data in which the change in shading or color changes within a short width, it is possible to generate a mist suction fan duty for each band printing to improve the response to image changes. Further, in the case of image data in which the change in shading or color changes over a long width, even if the mist suction fan duty is generated in units of multi-band printing, the response to the image change can be improved.

  Further, the control signal generating means can generate the control signal in a plurality of modes. In the first aspect, the control signal is accumulated to obtain an average value, and the obtained average value is used as a control signal to the mist suction fan control unit. The average value may be obtained by averaging the values obtained by multiplying the past cumulative value and the latest control signal by a predetermined coefficient, respectively, and performing weighting.

  In the second aspect, the control signal generating means compares the average value with the latest control signal, and when the average value is larger than the latest control signal, the average value is used as the control signal, and the average value is the latest control signal. When it is smaller than the signal, the latest control signal is used as a control signal to the mist suction fan control unit.

  According to the first aspect, by taking the average value, it is possible to suppress an excessive change in the rotational speed of the mist suction fan with respect to the change in the image data, and the discomfort caused by frequent rotational speed adjustments. The smooth rotation speed can be controlled.

  According to the second aspect, by appropriately using the average value and the latest control signal, it is possible to cope with sudden ink ejection, and both smooth control and rapid control of the rotation speed can be performed. Characteristics can be provided.

  Also, the drive control method of the mist suction fan in the inkjet image formation of the present invention is an inkjet image that records an image by ejecting ink from a recording head having a plurality of ink ejection nozzles onto a recording medium based on the image data. In the formation control, the method of calculating the ink discharge amount from the image data and the rotation of the mist suction fan according to the calculated discharge amount in the drive control method of the mist suction fan that sucks the mist of the ink floating in the air during printing A step of controlling the state and a step of suppressing the rotational speed or rotational driving time of the mist suction fan when the discharge amount is small are provided.

  As described above, according to the present invention, when data with a low print duty is printed, the noise generated when the fan motor is driven is reduced by suppressing the mist suction fan duty, and the noise when the suction fan is driven is reduced. It can be quiet.

  In addition, power consumption when the fan is driven can be suppressed.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. The embodiments described below are for explanation, and do not limit the scope of the present invention. Accordingly, those skilled in the art can adopt embodiments in which each of these elements or all of the elements are replaced with equivalent ones, and these embodiments are also included in the scope of the present invention.

  As an embodiment of an ink jet recording apparatus suitable for applying the present invention, a simple schematic diagram of an ink jet recording apparatus is shown in FIGS. 1 shows a front view of the image forming apparatus, FIG. 2 shows a view seen from the lateral direction, and FIG. 3 shows a view seen from the upper direction.

  In the ink jet recording apparatus, each of the plurality of heads has an ink discharge port 17 and is mounted on the carriage 15. The carriage 15 is supported so as to be movable in the main scanning direction along a guide (not shown), and the reciprocating operation of the carriage 15 is performed by a belt 13 suspended on a pulley 12 that is rotationally driven by a motor 11.

  2 and 3, an optical (photo) sensor unit 18 for measuring the end of the recording paper 19 and a cutter unit 24 are mounted on the carriage 15. The platen 20 is provided with an optical sensor unit 21 that detects the trailing edge of the cut sheet when the cut sheet is loaded, and a cutter groove 25 through which the blade of the cutter unit 24 passes when the sheet is cut.

  The carriage 15 is equipped with a linear scale sensor 16, and the linear scale 14 is arranged along the scanning direction of the carriage 15. The linear scale sensor 16 detects a slit of the linear scale 14 and thereby detects the scanning position of the carriage 15.

  Ink is ejected from the ink ejection port 17 of the head mounted on the carriage 15 at a predetermined timing. The ink ejection timing is determined based on the scanning position of the carriage 15 and is managed mainly based on the output of a linear encoder including the linear scale 14 and the linear scale sensor 16. For example, ink discharge control is started when the carriage 15 passes a certain point on the linear scale 14, and each color ink is discharged from the ink discharge port 17 according to the timing at which the carriage 15 passes a specific slit of the linear scale 14. Then, when a certain point on the linear scale 14 is passed, the ink ejection control is terminated.

  The ink discharge start and end positions are limited by the paper position detected by the optical sensors 18 and 21, the set margin amount, and the like, and are set based on image data created in advance.

  With the above configuration, the image forming apparatus discharges ink from the recording head to the recording medium based on the image data while moving the recording head including the plurality of ink discharge nozzles in the main scanning direction. After the image is recorded and the image for one band is recorded, the image is recorded on the recording medium by repeating the operation of transporting the recording medium by a predetermined amount in the sub-scanning direction.

  The operation of the image forming apparatus can be controlled by the CPU.

  The CPU controls the operation of the entire apparatus and controls each element connected via the system bus. As elements connected to the system bus, a RAM used as a work area of the CPU and a temporary data storage area, a firmware program for driving the image forming apparatus, and a boot program for controlling the firmware program are written. The image data is transferred via the interface unit (I / F) connected to the ROM used by the CPU, an external computer terminal device and the like.

  The CPU implements various processes by reading and executing a program written in the ROM.

  Also, the system bus has a panel operation unit for performing various settings of the image forming apparatus by the user, confirmation of the settings, etc., a non-volatile memory for storing the various settings, and for recording an image on a print object. Are connected.

  FIG. 4 is a block diagram illustrating a configuration example of a control device provided in the image forming apparatus of the present invention.

  The control device 30 includes a recording control unit 31, a carriage control unit 32, a discharge amount calculation unit 33, a mist suction fan control signal generation unit 34, and a mist suction fan control unit 35.

  The recording control unit 31 controls basic operations as the image forming apparatus, and controls external input processing, signal processing for recording based on the external input processing, and driving processing of the recording operation mechanism. And controlling the ejection of ink from each nozzle of the recording head 41 and controlling the operation of the carriage 42 via the carriage control 32.

  As a configuration for controlling the driving of the mist suction fan 43, the control device 30 has a discharge amount calculation unit 33 that calculates an ink discharge amount during printing, and a mist suction fan control unit that controls the rotation drive of the mist suction fan 43. 35 and a mist suction fan control signal generation unit 34 that generates a control signal of the mist suction fan control unit 35.

  The mist suction fan control signal generator 34 generates a control signal based on the ink discharge amount calculated by the discharge amount calculator 33. The mist suction fan control unit 35 controls the rotation state of the mist suction fan 43 based on the control signal generated by the mist suction fan control signal generation unit 34.

  It is necessary to control the rotational speed of the mist suction fan 43 in accordance with a change in the amount of mist generated. However, a specific measuring device is required to measure the generated mist, and it is impossible to directly measure the amount of generated mist in a normal state.

  The present inventor has found that there is a linear relationship between the ink ejection amount during printing and the number of dots during printing, and between the ink ejection amount during printing and the printing duty. Here, the print duty is a ratio of the ink discharge amount when the image data is printed to the ink discharge amount when the nozzle of each color of the head is printed at 100%, and the print duty of the image data with respect to the maximum ink discharge amount. This represents the ratio of the amount of mist generated by printing.

  From the above linear relationship, there is also a linear relationship between the print duty and the ratio at which the ejected ink becomes mist.

  FIG. 5 is a schematic diagram showing the relationship between the print duty and the generated mist. In FIG. 5, the horizontal axis of the graph represents the printing duty (%), and the vertical axis represents the ratio (%) of the ink (mist) dispersed in the air to the ejected ink. Here, the print duty is for all 6 colors (Bk: Black, C: Cyan, Lc: Light Cyan, M: Magenta, Lm: Light Magenta, Y: Yellow) when each nozzle discharges with the maximum discharge amount. 600% (100% x 6).

  FIG. 5 shows that 1.0% of the ejected ink becomes mist when the print duty is 108%, and 1.3% of the ejected ink becomes mist when the print duty is 216%.

  Further, since the ink discharge amount during printing is proportional to the number of dots at the time of printing, the above-described printing duty can be obtained from the number of dots at the time of printing.

  Therefore, since the printing duty and the generated mist amount are in a substantially proportional relationship, controlling the rotation speed of the mist suction fan with respect to the printing duty provides the same effect as when directly measuring the generated mist amount. be able to.

  Therefore, the discharge amount calculation unit 33 calculates the ink discharge amount during printing by counting the number of dots during printing based on the above relationship. The discharge amount calculation unit 33 includes dot counter means 33a, and thereby calculates the ink discharge amount by counting the number of dots output from the recording control unit 31 during printing.

  The mist suction fan control signal generation unit 34 includes a print duty calculation unit 34a that calculates the print duty and a control signal generation unit 34b that generates a control signal based on the calculated print duty.

  The print duty calculating unit 34a calculates the ink discharge amount when all the nozzles of the head print at 100% by the product of the number of dots representing the data length of the image data and the number of nozzles of each head, and the dot counter unit calculates The ink discharge amount when image data is printed is obtained from the sum of the numbers of dots of the respective heads, and the print duty is calculated by dividing the obtained sum by the product.

  As shown in the block diagram of FIG. 4, when image data is transmitted to the recording control unit 31, for example, when printing for one band, printing start processing, carriage and conveyance are performed based on the image data length. The system (not shown) drive processing and dot count start processing are performed to print one band of data. The dot count unit 33a counts the number of ejection dots for each color.

  When the printing is completed, the print duty calculation unit 34a acquires the image data length (dots) printed from the recording control unit 31, acquires the number of ejection dots of each color counted from the dot count unit 33a, and calculates the print duty x. .

The print duty x is calculated as follows, for example. The image data length is m (dot), the number of nozzles of each color of the head is n (nozzles), the dot count value of each color is Bk: a (dot), C: b (dot), Lc: c (dot), M: When d, Lm: e (dot), and Y: f (dot), the print duty x is x = ((a + b + c + d + e + f) / (m × n)) × 100 (%)
Is obtained.

  Further, the print duty calculating means 34a calculates the ink discharge amount when the image data is printed by calculating the sum of values obtained by multiplying the number of dots of each color nozzle by a predetermined coefficient set for each nozzle and performing weighting. May be.

For example, when coefficients k1 to k6 are set for Bk, C, Lc, M, Lm, and Y for each color, the print duty x is
x = ((a · k1 + b · k2 + c · k3 + d · k4 + e · k5 + f · k6) / (m × n)) × 100 (%)
Thus, weighting can be performed by these coefficients k1 to k6.

  By setting the weight of the number of dots of each color nozzle, it is possible to make a setting in accordance with the characteristics of the amount of ink discharged from the nozzle. For example, if the ink discharge amount varies depending on the color, setting the weighting coefficient according to the discharge amount characteristic makes it possible to set the print duty smaller than when handling the number of dots uniformly, and noise Can be further reduced.

  The control signal generation unit 34b is a suction fan duty generation unit 34b1 that generates a mist suction fan duty that determines a PWM ratio of a drive signal for controlling the pulse width of the rotation speed of the mist suction fan 43, or a rotation drive time of the mist suction fan 43. Rotation drive time generation means 34b2 for generating. The suction fan duty generation means can control the rotation speed of the mist suction fan, and the rotation drive time generation means can control the rotation drive time of the mist suction fan.

  Hereinafter, generation of the mist suction fan duty performed by the suction fan duty generation means will be described.

  FIG. 6 shows the relationship between the printing duty and the number of rotations of the suction fan effective for sucking mist, the horizontal axis shows the printing duty (%), and the vertical axis shows the PWM duty (%) of the mist suction fan. Is shown.

  When the mist suction fan 43 is driven by PWM (pulse width modulation) control, the rotational speed is controlled by a PWM signal. Here, the PWM signal for controlling the mist suction fan 43 is set by the mist suction fan PWM duty (hereinafter referred to as PWM duty).

  In fan control by PWM control, a stable rotational speed cannot be obtained unless driven by a PWM duty having a certain size. This is because, in the case of a small PWM duty, the ratio of the time width of the drive current supplied to the mist suction fan 43 decreases, so that the rotation may become unstable.

  Therefore, as an example here, the drive condition that the PWM duty is 60% when the print duty is 30% is the lower limit drive condition, and the drive condition that the PWM fan duty is 100% when the print duty is 230% or more Is the upper limit drive condition.

  Note that 100% PWM fan duty means that the time width during which the drive current is supplied is 100%, so 100% is the upper limit value of the PWM fan duty.

  The suction fan duty generation unit 34b1 obtains the mist suction fan duty y based on the print duty x calculated by the print duty calculation unit 34a.

  From the relationship shown in FIG. 6, the PWM fan duty is 60% when the printing duty is 30% or less, and the PWM fan duty is 100% when the printing duty is 230% or more.

  Further, when the printing duty is 30% to 230%, the change amount from the printing duty 30% to 230% is 200%, whereas the mist suction fan PWM duty is 60% from the relationship shown in FIG. The amount of change is 40%.

  Therefore, when the print duty varies between 30% and 230%, the slope of the graph is 0.2 (= 40% / 200%), so the mist suction fan in the range where the print duty is between 30% and 230% The conversion factor to PWM duty is 0.2.

Thereby, when the print duty x is in the range of 30% to 230%, the suction fan PWM duty y is obtained by the following equation.
y = (x-30) x 0.2 + 60 (%)
It becomes.

Hereinafter, description will be made using a numerical example. As one numerical example, image data length m: 28327 (dot), number of nozzles n: 1280 (nozzle), dot count value for each color, Bk: 4022738 (dot), C: 5632836 (dot), Lc: 6327973 (dot), M: 2649327 (dot), Lm: 3829139 (dot), Y: 2682913 (dot)
The print duty x is x = ((4022738 + 5632836 + 6327973 + 2649327 + 3829139 + 2682913)
/(28327×1280))×100≒69.35(%)
It becomes.

Since this print duty x (= 69.35) is in the range of 30 ≦ 69.35 ≦ 230 (%), the suction fan PWM duty y to be set is calculated from the above formula of the suction fan PWM duty y.
y = (69.35-30) × 0.2 + 60 = 67.87 (%)
Is obtained.

  Based on this PWM duty y, the rotational speed of the mist suction fan 43 is controlled by sending a PWM signal from the mist suction fan controller 35 to the mist suction fan 43.

  7 and 8 are a flowchart and a timing chart for explaining an operation example by the mist suction fan control signal generating means.

  The recording control unit 31 generates data for one band or several bands based on the input image data (FIG. 8A), and sends the data to the recording head 41 and also to the carriage control unit 32 to drive the carriage 42. Then, printing is performed (S1) (FIG. 8B).

  The ejection amount calculation unit 33 acquires the image data length (dot number) m from the recording control unit 31, and counts the number of dots of each color by the dot counter means 33a (S2). The print duty calculating unit 34a acquires the number of dots a to f counted from the dot counter unit 33a as the ejection amount (S3), and calculates the print duty x (S4) (FIG. 8C).

  The suction fan duty generation means 34b1 of the control signal generation means 34b calculates the mist suction fan duty y using the calculated printing duty x (S5) (FIG. 8 (d)).

  The mist suction fan control unit 35 calculates a PWM signal based on the mist suction fan duty y calculated by the suction fan duty generation means 34b1 (S6), and sends it to the mist suction fan 43 (S7). The mist suction fan 43 is rotationally driven based on the sent PWM signal (S8) (FIG. 8 (e)). The above steps are repeated until printing is completed (S9).

  As described above, by setting the mist suction fan PWM duty based on the print duty, it is possible to control the optimum mist suction fan rotation speed according to the amount of mist generated.

  In the above example, when calculating the fan PWM duty from the print duty, the calculation formula is used. However, a data table for obtaining the fan PWM duty using the print duty as an index is prepared, and this data table is used. You may obtain | require by performing conversion.

  In the above example, the PWM duty is updated every time one band is printed. However, the update may be performed once every a plurality of bands or every predetermined time during printing.

  The mist suction fan control signal generation means 34 can be configured to include a parameter setting means 34c for setting parameters that define the relationship of the control signal with respect to the print duty.

  The control signal generator 34b generates a control signal for the print duty according to the parameter set by the parameter setting unit 34c, and can change the print duty by changing the parameter.

  The parameter setting unit 34c can use, for example, a scanning speed for moving the head in the main scanning direction as a parameter. When the scan speed is used as a parameter, the suction fan duty generation unit 34b1 generates a mist suction fan duty for the print duty according to the magnitude of the scan speed.

  The parameter setting unit 34c can use the number of bands or the time width as a parameter, thereby changing the time width for generating the mist suction fan duty according to the number of bands or the time width. Here, the number of bands can be one band or a plurality of bands.

  The suction fan duty generation unit 34b1 can generate a mist suction fan duty for each band printing or in units of a plurality of bands, thereby setting the drive control interval of the mist suction fan in units of bands. For example, in the case of image data in which the change in shading or color changes within a short width, a mist suction fan duty is generated for each band printing to improve the response to the image change. In the case of image data in which the change of image data changes with a long width, it is possible to improve the response to the image change by generating the mist suction fan duty in units of multi-band printing.

  FIG. 9 is a flowchart for explaining an operation example by the parameter setting means.

  In the step of calculating the PWM signal in S6, it is determined in the parameter setting means whether the scan speed parameter is set to high speed or low speed (S11).

  When the high scan speed parameter is set, as shown in FIG. 6, the high speed mist suction fan duty characteristic is selected (S12), and the low scan speed parameter is set. As shown in FIG. 6, the mist suction fan duty characteristic for low speed is selected (S13). A PWM signal is calculated using the selected mist suction fan duty characteristic (S14).

  By setting the ratio of the mist suction fan duty to the print duty to be a large parameter, even when the print duty is small, the rotation speed of the mist suction fan can be increased to speed up the mist suction, making it compatible with high-speed scanning. When the scan speed is low, the mist suction fan duty ratio with respect to the print duty is set to a small parameter so that the rotation speed of the mist suction fan is compared with that during high-speed scan even when the print duty is large. It can be kept low and compatible with low-speed scanning.

  When the control signal generation unit 34b includes the rotation drive time generation unit 34b2 that generates the rotation drive time of the mist suction fan 43, the drive noise of the mist suction fan is reduced by controlling the rotation drive time of the mist suction fan. Can be made.

  10 and 11 are a flowchart and a timing chart for explaining an operation example by the rotation drive time generating means.

  In the same manner as in steps S1 to S3 in FIG. 7, the recording control unit 31 generates data for one band or several bands based on the input image data (FIG. 11A), and the recording head. 41 and the carriage control unit 32 to drive the carriage 42 to perform printing (FIG. 11B), and the ejection amount calculation unit 33 obtains the image data length (number of dots) m from the recording control unit 31. Then, the dot counter means 33a counts the number of dots of each color, and the print duty calculation means 34a acquires the number of dots a to f counted from the dot counter means 33a as the ejection amount (S21).

  The print duty calculator 34a calculates the print duty x (S22) (FIG. 11 (c)).

  The rotation drive time generation means 34b2 of the control signal generation means 34b calculates the drive time t of the mist suction fan using the calculated print duty x (S23) (FIG. 11 (d)).

  The mist suction fan control unit 35 sends the drive time t of the mist suction fan calculated by the rotation drive time generation means 34b2 to the mist suction fan 43, and the mist suction fan 43 is rotationally driven based on the sent drive time t. (S24) (FIG. 11E). The above steps are repeated until printing is completed (S25).

  As described above, by setting the driving time of the mist suction fan based on the print duty, it is possible to control the optimal driving time of the mist suction fan according to the amount of mist generated.

  The control signal generation means of the present invention can generate a control signal according to another aspect in addition to the above aspect.

  One aspect is an aspect in which the control signals are accumulated to obtain an average value, and the obtained average value is used as a control signal to the mist suction fan control unit. The average value is obtained by averaging the values obtained by multiplying the past cumulative value and the latest control signal by a predetermined coefficient, respectively, in addition to the simple average value of the past cumulative value. Also good.

  12 and 13 are a flowchart and a timing chart for explaining an operation example in which the mist suction fan control is performed using the average value.

  In the same manner as in steps S1 to S4 in FIG. 7, the recording control unit 31 generates data for one band or several bands based on the input image data (FIG. 13A), and the recording head. 41 and the carriage controller 32 to drive the carriage 42 to perform printing (FIG. 13B), and the ejection amount calculator 33 obtains the image data length (number of dots) m from the recording controller 31. Then, the dot counter means 33a counts the number of dots of each color, and the print duty calculation means 34a acquires the number of dots a to f counted from the dot counter means 33a as the discharge amount and calculates the print duty x of the band being printed. After calculating (S31) (FIG. 13 (c)), the suction fan duty generating unit 34b1 of the control signal generating unit 34b uses the calculated print duty x to output the current printing band. Calculating a suction fan duty y of (S32) (FIG. 13 (d)).

  The suction fan duty generation unit 34b1 reads the cumulative value of the suction fan duty for a predetermined number of bands in the past (S33) (FIG. 13E), and uses the read cumulative value of the suction fan duty to generate the mist suction fan duty. (S34) (FIG. 13 (f)).

  The mist suction fan control unit 35 performs mist suction control using the average value of the mist suction fan duty calculated by the suction fan duty generation means 34b1 (FIG. 13 (g)). The mist suction control can be performed by the steps S6 to S8 in FIG. 7 (S35).

  After updating the accumulated value of the mist suction fan duty (S36), the above steps are repeated until printing is completed (S37).

  As described above, by setting the driving time of the mist suction fan based on the print duty, it is possible to control the optimal driving time of the mist suction fan according to the amount of mist generated.

  According to this aspect, by taking the average value, it is possible to suppress an excessive change in the rotational speed of the mist suction fan with respect to a change in the image data, and to avoid discomfort caused by frequent rotational speed adjustments. Smooth control of the rotation speed can be performed.

  In another aspect, the average value is compared with the latest control signal. When the average value is larger than the latest control signal, the average value is set as the control signal. When the average value is smaller than the latest control signal, the latest value is updated. In this aspect, the control signal is used as a control signal to the mist suction fan control unit.

  14 and 15 are a flowchart and a timing chart for explaining an operation example in which mist suction fan control is performed by selecting a current value and an average value for the mist suction fan duty.

  In the same manner as in steps S1 to S4 in FIG. 7, the recording control unit 31 generates data for one band or several bands based on the input image data (FIG. 15A), and the recording head. 41 and the carriage controller 32 to drive the carriage 42 to perform printing (FIG. 15B), and the ejection amount calculator 33 obtains the image data length (number of dots) m from the recording controller 31. Then, the dot counter means 33a counts the number of dots of each color, and the print duty calculation means 34a acquires the number of dots a to f counted from the dot counter means 33a as the discharge amount and calculates the print duty x of the band being printed. Calculation (S41) (FIG. 15 (c)), the suction fan duty generation means 34b1 of the control signal generation means 34b uses the calculated print duty x to output the current printing band. Calculating a suction fan duty y of (S42) (FIG. 15 (d)).

  The suction fan duty generation unit 34b1 reads the cumulative value of the suction fan duty for a predetermined number of bands in the past (S43) (FIG. 15E), and uses the read cumulative value of the suction fan duty for the mist suction fan duty. Is averaged (S44) (FIG. 15 (f)).

  The mist suction fan control unit 35 compares the average value of the mist suction fan duty calculated by the suction fan duty generation means 34b1 with the mist suction fan duty of the currently processed band (S45).

  When the mist suction fan duty of the band currently being processed is larger than the past average value, the mist suction control is performed with the mist suction fan duty of the band currently being processed (rotation speed 1 in FIG. 15G). . The mist suction control can be performed by the steps S6 to S8 in FIG. 7 (S46).

  If the mist suction fan duty of the band currently being processed is smaller than the past average value, the mist suction control is performed using the average value of the mist suction fan duty (rotation speed 2 in FIG. 15G).

  The mist suction control can be performed by the steps S6 to S8 in FIG. 7 (S47).

  After updating the accumulated value of the mist suction fan duty (S48), the above steps are repeated until printing is completed (S49).

  According to this aspect, by appropriately using the average value and the latest control signal, it is possible to cope with sudden ink ejection, and both the smooth control of the rotational speed and the quick control can be achieved. Can be provided.

1 is a front view of an image forming apparatus of the present invention. FIG. 3 is a diagram of the image forming apparatus of the present invention viewed from the lateral direction. FIG. 2 is a diagram viewed from above the image forming apparatus of the present invention. FIG. 2 is a block diagram illustrating a configuration example of a control device provided in the image forming apparatus of the present invention. It is the schematic which shows the relationship between printing duty and the generated mist. It is a figure which shows the relationship between printing duty and the rotation speed of the suction fan effective in attracting | sucking mist. It is a flowchart for demonstrating the operation example by the mist suction fan control signal production | generation means of this invention. It is a timing chart for demonstrating the operation example by the mist suction fan control signal production | generation means of this invention. It is a flowchart for demonstrating the operation example by the parameter setting means of this invention. It is a flowchart for demonstrating the operation example by the rotational drive time production | generation means of this invention. It is a timing chart for demonstrating the operation example by the rotational drive time production | generation means of this invention. It is a flowchart for demonstrating the operation example which performs mist suction fan control using the average value of this invention. It is a timing chart for demonstrating the operation example which performs mist suction fan control using the average value of this invention. It is a flowchart for demonstrating the operation example which selects a present value and an average value, and performs mist suction fan control about the mist suction fan duty of this invention. It is a timing chart for demonstrating the operation example which selects a present value and an average value, and performs mist suction fan control about the mist suction fan duty of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Motor 12 Pulley 13 Belt 14 Linear scale 15 Carriage 16 Linear scale sensor 17 Ink discharge port 18 Optical (photo) sensor unit 19 Recording paper 20 Platen 21 Optical sensor units 22 and 23 Roller 24 Cutter unit 25 Cutter groove 30 Control device 31 Recording control unit 32 Carriage control unit 33 Discharge amount calculation unit 34 Mist suction fan control signal generation unit 34a Print duty calculation unit 34b Control signal generation unit 34b1 Suction fan duty generation unit 34b2 Rotation drive time generation unit 35 Mist suction fan control unit 41 Recording head 42 Carriage 43 Mist suction fan

Claims (15)

In an image forming apparatus that records an image by ejecting ink onto a recording medium from a recording head having a plurality of ink ejection nozzles based on image data,
A control device (30) for controlling the ejection of ink according to the image data, and a mist suction fan (43) for sucking the mist of ink floating in the air during printing,
The image forming apparatus, wherein the control device (30) controls a rotation state of the mist suction fan (43) in accordance with an ink discharge amount at the time of printing. The control device (30)
A recording control unit (31) for controlling a printing operation of the image data on a recording medium, an ejection amount calculation unit (33) for calculating an ink ejection amount at the time of printing,
A mist suction fan control unit (35) for controlling the rotational drive of the mist suction fan (43);
A mist suction fan control signal generator (34) for generating a control signal of the mist suction fan controller (35),
The mist suction fan control signal generator (34) generates a control signal based on the ink discharge amount calculated by the discharge amount calculator (33).
The image forming apparatus according to claim 1, wherein the mist suction fan control unit (35) controls a rotation state of the mist suction fan (43) based on the control signal.   The discharge amount calculation unit (33) includes dot counter means (33a) for calculating the ink discharge amount by counting the number of dots output from the recording control unit 31 during printing. The image forming apparatus described in 1. The mist suction fan control signal generator (34)
A print duty calculating means (34a) for calculating, as a print duty, a ratio of the ink discharge amount when the image data is printed to the ink discharge amount when the nozzle of each color of the head is printed at 100%;
The image forming apparatus according to claim 2, further comprising a control signal generation unit (34 b) that generates the control signal based on the calculated print duty. The printing duty calculation means (34a)
The product of the number of dots representing the data length of the image data and the number of nozzles of each head determines the ink discharge amount when all the nozzles of the head print at 100%,
The ink discharge amount when the image data is printed is obtained by the sum of the number of dots of each head calculated by the dot counter means (33a),
The image forming apparatus according to claim 4, wherein the print duty is calculated by dividing the sum by the product.   The print duty calculation means (34a) obtains the sum of values obtained by multiplying the number of dots of the nozzles of each color by a predetermined coefficient set for each nozzle and weighting the ink, thereby ejecting ink when the image data is printed The image forming apparatus according to claim 5, wherein: The control signal generating means (34b)
Suction fan duty generation means (34b1) for generating a mist suction fan duty for determining a PWM ratio of a drive signal for controlling the pulse width of the rotation speed of the mist suction fan, or a rotation drive time generation for generating a rotation drive time of the mist suction fan 5. The image forming apparatus according to claim 4, wherein the image forming apparatus is means (34b2). Parameter setting means (34c) for setting a parameter for determining the relationship of the control signal with respect to the print duty;
8. The control signal generating means (34b) generates a control signal for a print duty in accordance with a parameter set by the parameter setting means (34c). The image forming apparatus described. The parameter setting means (34c) uses, as a parameter, a scanning speed for moving the head in the main scanning direction,
The image forming apparatus according to claim 8, wherein the suction fan duty generation unit (34b1) generates a mist suction fan duty with respect to a print duty in accordance with a magnitude of the scan speed. The parameter setting means (34c) uses the number of bands or time width as a parameter,
9. The image forming apparatus according to claim 8, wherein the suction fan duty generation unit (34b1) changes a time width for generating the mist suction fan duty according to the number of bands or the time width.   The number of bands is one band or a plurality of bands, and the suction fan duty generation means (34b1) generates a mist suction fan duty for each one band printing or a plurality of bands as a unit. The image forming apparatus described.   12. The control signal generator (34b) according to any one of claims 4 to 11, wherein the control signal generation means (34b) accumulates control signals to obtain an average value, and uses the average value as a control signal to a mist suction fan control unit. The image forming apparatus described in 1.   13. The image forming apparatus according to claim 12, wherein the average value is obtained by averaging a value obtained by multiplying a past cumulative value and a latest control signal by a predetermined coefficient and weighting the average value. . The control signal generation means (34b) compares the average value with the latest control signal,
When the average value is larger than the latest control signal, the average value is a control signal,
14. The image forming apparatus according to claim 12, wherein when the average value is smaller than the latest control signal, the latest control signal is used as a control signal to the mist suction fan control unit. A mist suction fan for sucking mist of ink floating in the air during printing in image formation in which an image is recorded by ejecting ink to a recording medium from a recording head having a plurality of ink ejection nozzles based on image data In the drive control method,
Calculate the ink discharge amount from the image data,
Control the rotation state of the mist suction fan according to the calculated discharge amount,
A drive control method for a mist suction fan in image formation, characterized in that the rotation speed or rotation drive time of the mist suction fan is suppressed when the discharge amount is small.

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