JP2004051287A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an image forming apparatus capable of suppressing a double feeding by properly controlling a sorting fan. <P>SOLUTION: This image forming apparatus comprises a sheet feed cassette 30 storing transfer paper sheets for image formation, a blowing means 135 blowing air for sorting to the transfer paper sheets stored in the sheet feed cassette, a sheet feed means 31 for feeding the transfer sheets from the sheet feed cassette, a double feed detection means 150 detecting the double feed of the transfer sheets when the sheets are fed by the sheet feed means, and a control means 101 controlling the air volume of the blowing means by referring to the results of double feed detection by the double feed detection means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus that considers double feeding when feeding transfer paper.
[0002]
[Prior art]
2. Description of the Related Art In image forming apparatuses such as printers, copiers, and facsimile machines, transfer paper for image formation is stored in a paper feed cassette, and the transfer paper is fed from the paper feed cassette to a paper feed unit such as a paper feed roller. It has a structure that sends it out.
[0003]
At this time, if two or more transfer sheets are sent out simultaneously or with a slight delay in a state where they are overlapped, a blank sheet may be mixed or a jam may occur.
For this reason, there are a small number of devices configured to avoid double feeding by blowing air from a blowing means such as a loosening fan near the outlet of the paper feeding cassette to the transfer paper during paper feeding. are doing. Many image forming apparatuses do not have a separating fan.
[0004]
Further, an ultrasonic wave is transmitted to the transfer paper at the time of paper feeding, an ultrasonic wave that has passed through the transfer paper is received, and a double feed of the transfer paper is detected based on a level of a signal level of the received ultrasonic wave. Some image forming apparatuses have a detecting unit. In this case, the double feed is detected by utilizing the fact that the attenuation of the ultrasonic wave is small in the case of one transfer sheet and the attenuation of the ultrasonic wave is large in the case of two or more transfer sheets. .
[0005]
[Problems to be solved by the invention]
Even in the image forming apparatus provided with the separating fan described above, the air volume control of the separating fan has not been performed. That is, in an image forming apparatus having a separating fan, the apparatus is always used in an on state. For this reason, it is not a desirable state from the viewpoint of power consumption and noise.
[0006]
Also, in an image forming apparatus provided with double feed detection using ultrasonic waves, the ultrasonic frequency and judgment reference values are determined according to the paper type (paper thickness, material, surface finish, etc.) and the environment (temperature, humidity, etc.). No control was set or changed.
[0007]
Accordingly, a first object of the present invention is to realize an image forming apparatus capable of suppressing double feeding by appropriate control of a separating fan.
A second object of the present invention is to realize an image forming apparatus capable of accurately detecting a double feed without being affected by a paper type using an ultrasonic wave.
[0008]
[Means for Solving the Problems]
That is, the present invention for solving the above problems is as described below.
(1) A first aspect of the present invention is a paper feed cassette for storing transfer paper for image formation, and a blowing means for blowing air for separating the transfer paper stored in the paper feed cassette. Reference is made to paper feeding means for feeding out the transfer paper from the paper feed cassette, double feed detecting means for detecting double feeding of the transfer paper at the time of paper feeding by the paper feeding means, and a double feed detection result by the double feed detecting means. And a control unit for controlling the air volume of the blowing unit.
[0009]
According to the present invention, when the transfer paper is sent out from the paper feed cassette by the paper feed means, the transfer paper stored in the paper feed cassette is blown by the blowing means for the separation paper. The control means controls the air volume of the blowing means with reference to the result of the double feed detection by the means.
[0010]
As a result, it is possible to appropriately control the blowing means (separating fan) based on the result of double feed detection, and it is possible to suppress double feed.
(2) The invention according to claim 2 is the image forming apparatus according to claim 1, wherein each of a plurality of paper feed cassettes includes the blower.
[0011]
According to the present invention, each of the plurality of paper feed cassettes is provided with the air blowing means, and in each of the paper feed cassettes, it is possible to appropriately control the air blowing means (separating fan) based on the result of the double feed detection, thereby suppressing double feeding. It becomes possible to do.
[0012]
(3) The invention according to claim 3, further comprising a display unit for displaying a state of the image forming apparatus, wherein the control unit performs control for displaying a control state of the air volume of the blowing unit on the display unit. An image forming apparatus according to claim 1 or 2, wherein
[0013]
In the present invention, the control means performs control for displaying the control state of the air volume of the blowing means on the display unit.
As a result, appropriate control of the blowing means (separating fan) based on the double feed detection result becomes possible, and not only can double feed be suppressed, but also double feed suppression control is performed because double feed has occurred. This allows the user to know the state in which the user is operating.
[0014]
(4) The invention according to claim 4, further comprising: a display unit for displaying a state of the image forming apparatus; a plurality of sheet cassettes each including the blowing unit; 3. The image forming apparatus according to claim 1, wherein control is performed to display, on the display unit, a control state of the air volume of each of the blowing units provided in each of the units. 4.
[0015]
In the present invention, the control means performs control for displaying the control state of the air volume of the blowing means provided on each of the plurality of paper feed cassettes on the display unit.
As a result, appropriate control of the blowing means (separating fan) based on the double feed detection result becomes possible in each paper feed cassette, so that double feed can be suppressed. The user can know the paper feed stage in the state where the feed inhibition control is being performed.
[0016]
(5) The invention according to claim 5, wherein a paper feed cassette for storing transfer paper for image formation, paper feed means for feeding out the transfer paper from the paper feed cassette, and paper feeding by the paper feed means Transmitting the ultrasonic waves to the transfer paper, receiving the ultrasonic waves passing through the transfer paper, and detecting the double feed of the transfer paper based on the signal level of the received ultrasonic waves; An image forming apparatus comprising: a control unit that performs control for changing a determination criterion of an ultrasonic transmission / reception frequency or a reception signal level in a detection unit.
[0017]
According to the present invention, the ultrasonic wave is transmitted to the transfer paper at the time of paper feeding by the paper feeding means, the ultrasonic wave passing through the transfer paper is received by the double feed detecting means, and the signal level of the received ultrasonic wave is received. In this case, the control unit executes control to change the ultrasonic transmission / reception frequency or the criterion of the received signal level in the double feed detection unit.
[0018]
In this way, by changing the ultrasonic transmission / reception frequency or reception signal level judgment criteria in the double feed detection means, it is possible to accurately detect the double feed without being affected by the paper type using the ultrasonic waves. become.
[0019]
(6) The invention according to claim 6, wherein the control means transmits a plurality of ultrasonic waves with the ultrasonic transmission / reception frequency changed to the transfer paper being conveyed, and receives the ultrasonic waves passing through the transfer paper. 6. The image forming apparatus according to claim 5, wherein control is performed to change at least one of the ultrasonic transmission / reception frequency and the criterion according to the signal level.
[0020]
According to the present invention, the ultrasonic wave is transmitted to the transfer paper at the time of paper feeding by the paper feeding means, the ultrasonic wave passing through the transfer paper is received by the double feed detecting means, and the signal level of the received ultrasonic wave is received. In this case, a plurality of ultrasonic waves with the ultrasonic transmission / reception frequency changed are transmitted to the transfer paper being conveyed, and the ultrasonic waves passing through the transfer paper are detected. The control means executes control for changing the ultrasonic transmission / reception frequency or the criterion of the received signal level according to the received signal level.
[0021]
As described above, a plurality of ultrasonic waves in a state where the ultrasonic transmission / reception frequency is changed are transmitted to the transfer paper being conveyed, and the multiple feed detection unit is referred to by referring to the signal level at which the ultrasonic wave passing through the transfer paper is received. By changing the ultrasonic transmission / reception frequency or the criterion of the received signal level in the above, it is possible to accurately detect the double feed without being affected by the paper type using the ultrasonic waves.
[0022]
(7) In the invention according to claim 7, the control means transmits a plurality of ultrasonic waves in a state in which the ultrasonic transmission / reception frequency is changed to the transfer paper being conveyed, and performs a non-double feed and a double feed. 6. The image forming apparatus according to claim 5, wherein control is performed to change at least one of the ultrasonic transmission / reception frequency and the determination criterion according to each signal level of the ultrasonic wave that has passed through the transfer paper. is there.
[0023]
According to the present invention, the control unit transmits a plurality of ultrasonic waves with the ultrasonic transmission / reception frequency changed to the transfer paper being conveyed, and transmits the ultrasonic waves that have passed through the transfer paper at the time of non-double feeding and at the time of double feeding. Is controlled to change at least one of the ultrasonic transmission / reception frequency and the criterion according to the signal level of the received signal. That is, the ultrasonic transmission / reception frequency or the criterion determined at the time of non-multifeed is corrected with reference to the reception level at the time of multifeed.
[0024]
In this way, the ultrasonic transmission frequency or the judgment criterion is corrected by referring to the reception level at the time of double feeding, so that the double feeding can be accurately performed without being affected by the paper type using the ultrasonic waves. It becomes possible to detect.
[0025]
(8) The invention according to claim 8, further comprising an operation unit for performing various inputs, wherein the control unit refers to the information of the transfer paper input from the operation unit and refers to the ultrasonic transmission / reception frequency or the determination criterion. 6. The image forming apparatus according to claim 5, wherein at least one of the image forming apparatus is changed.
[0026]
According to the present invention, control is performed so as to change at least one of the ultrasonic transmission / reception frequency and the criterion by referring to various types of information regarding the transfer paper input from the operation unit.
[0027]
In this way, by determining or correcting the ultrasonic transmission / reception frequency or judgment criteria with reference to the information input from the operation unit, the multi-feed can be accurately detected without being affected by the paper type using the ultrasonic waves. It becomes possible to do.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram illustrating an example of an electrical configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a side sectional view illustrating a mechanical configuration of the image forming apparatus according to the embodiment of the present invention. FIG. 4 is an explanatory view showing a state of arrangement of a separating fan constituting a blowing means.
[0029]
First, the entire image forming apparatus will be described with reference to FIG. In this embodiment, a description will be given using a copying machine as an image forming apparatus.
In FIG. 2, a plurality of originals d with the front surface of the first page of the original facing upward are placed on the original placing portion 11 of the ADF 10 capable of feeding both sides of the original. The first document fed out through the rollers 12a and 12b is rotated and conveyed through the rollers 13.
[0030]
Next, the light source 23 irradiates the original surface of the original d, and the reflected light forms an image on a light receiving surface of a CCD 28 serving as a photoelectric conversion unit via an imaging optical system 27 via mirrors 24, 25 and 26. Here, the light source 23, mirrors 24, 25, and 26, an optical system having an imaging optical system 27 and a CCD 28, and an optical system driving unit (not shown) constitute an image reading unit 20.
[0031]
In FIG. 2, when the document d is placed on the platen glass 21 with the reading surface facing down, the optical system scans along the platen glass 21 to perform reading.
[0032]
When the document d is automatically fed and goes around the roller 13, reading is performed with the light source 23 and the mirror 24 fixed below the second platen glass 22. Then, the read image data of the document d is sent from the CCD 28 to an image processing unit 120 (not shown).
[0033]
When the document d is automatically fed by the ADF 10, when the first page of the document d is read, a winding operation using the roller 13 is performed again through the reversing roller 14, and the back side of the document is read. Are read by the image reading unit 20 and sent to the image processing unit 120.
[0034]
In this way, the document d on which the images on the front surface and the back surface are read is again inverted by the reversing roller 14 and is stacked on the sheet discharge tray 16 with the front surface facing downward.
The image data read by the image reading unit 20 in this manner is subjected to predetermined image processing by the image processing unit 120, and then compressed and stored in the image memory.
[0035]
On the other hand, the transfer paper p is fed out from the paper feed cassette 30 (30a to 30c) on which the transfer paper is loaded by the paper feed rollers 31 (31a to 31c), and is fed to the image forming unit 50. At this time, loosening fans 135a to 135c are provided in each of the paper feed cassettes 30a to 30c, and blow air for loosening the transfer paper sent out from the paper feed cassette under the control of a control unit described later. ing.
[0036]
Then, the transfer paper sent from each paper feed cassette is subjected to ultrasonic transmission and reception by the double feed detection sensor 150 to detect whether the transfer paper is in the double feed state or the non-double feed state. This detection is performed by comparing the result of the transmission and reception of the ultrasonic wave by the double feed detection sensor 150 with a predetermined criterion by a control unit described later.
[0037]
The transfer paper p fed to the image forming section 50 is synchronized with the image forming timing and the feed timing by the registration roller 32 near the entrance thereof, and then comes close to the photosensitive drum 51 serving as an image carrier. I do.
[0038]
Image data is input from the image processing unit to the image writing unit 40, and a laser beam corresponding to the image data is emitted from the laser diode in the image writing unit 40 onto the photosensitive drum 51 to form an electrostatic latent image. By developing the electrostatic latent image in the developing unit 53, a toner image is formed on the photosensitive drum 51.
[0039]
This toner image is transferred to the transfer paper p by the transfer section 54 below the photosensitive drum 51. Then, the transfer paper p that is in contact with the photosensitive drum 51 is separated by the separation unit 55. The transfer paper p separated from the photosensitive drum 51 enters the fixing unit 59 via the transport mechanism 58, and the toner image is fixed by heat and pressure. Thus, an image is formed on the transfer paper p.
[0040]
In the case where it is necessary to perform reverse re-feeding when forming a two-sided image, the transfer paper p on which the toner image has been fixed is conveyed downward via the guide 61 and enters the reversing unit 63. Next, the transfer paper p contained in the reversing unit 63 is fed out again by the reversing roller, and is sent again to the image forming unit 50 via the reversing conveyance path 64. In the image forming unit 50 where the image formation on one side of the document d has been completed, the toner adhered to the photosensitive drum 51 is removed by the cleaning unit 56, and is prepared for the next image formation.
[0041]
In this state, the other surface of the transfer paper p (the surface on which no image has been formed) is carried into the image forming unit 50, and an image is formed. The transfer paper p separated from the photosensitive drum 51 by the separation unit 55 enters the fixing unit 59 again via the transport mechanism 58 and is fixed. In this manner, the transfer paper p on which the image formation on the back surface and the front surface has been completed, or the transfer paper p on which the image formation on one surface has been completed, is discharged out of the apparatus.
[0042]
Here, with reference to FIG. 1, an image forming apparatus according to the present embodiment which can suppress double feeding by appropriate control of the separating fan will be described.
In FIG. 1, a CPU 101 controls each part of the image forming apparatus and controls the suppression of double feed by appropriate control of a loosening fan when feeding the transfer paper p in the present embodiment. It is a control means constituted by such as.
[0043]
Reference numeral 110 denotes an operation display unit for displaying the status of the image forming apparatus and inputting various information. The operation display unit 110 includes an operation unit 111 for inputting information by an operator and a display unit 112 for displaying the status of the image forming apparatus. ing.
[0044]
Reference numeral 120 denotes an image processing unit that performs image processing in response to an instruction from the control unit 101.
Reference numeral 130 denotes a paper feed unit that feeds the transfer paper p, and includes a plurality of paper feed cassettes 30 (30a to 30c) and paper feed rollers 31 (31a to 31c) shown in FIG. A separation fan 135 (135a to 135c) is provided in the sheet cassette, and the separation fan blows the transfer paper sent from the sheet cassette under the control of the control unit 101.
[0045]
As shown in FIG. 3, inside the paper feed cassette 30, there are provided regulating plates 132, 133, and 134 for positioning the transfer paper p, and near the exit of the transfer paper between the regulating plates 132 and 134 on the side surfaces. Are provided with separating fans 135 and 135 '. Then, loose air is blown from the side toward the center (FIGS. 3A and 3B).
[0046]
Reference numeral 140 denotes a writing unit which receives a processing result of the image processing unit 120 and writes an image on the photosensitive drum 51 by a laser beam, and is an electrical component of the writing unit 40 in FIG.
[0047]
Reference numeral 150 denotes a double feed detection sensor for detecting whether the transfer paper sent from each sheet cassette by the ultrasonic transmission / reception is in the double feed state or the non-double feed state, and is configured by an ultrasonic transmitter and an ultrasonic receiver. Have been. The detection by the double feed detection sensor 150 is performed by the control unit 101 comparing the result of the ultrasonic transmission and reception by the double feed detection sensor 150 with a predetermined criterion.
[0048]
FIG. 4 is a block diagram showing the relationship between the double feed detection sensor 150 and the control means 101. The double feed detection sensor 150 includes a transmitter 151 that transmits an ultrasonic wave toward the transfer paper p, and a receiver 152 that receives the ultrasonic wave that has passed through the transfer paper p.
[0049]
An oscillation signal from an oscillation circuit 153 that oscillates an oscillation signal having a frequency based on an instruction from the control unit 101 is supplied to a transmitter 151 via a power amplification circuit 154.
[0050]
The transmitted wave that has passed through the transfer paper p is converted into an electric signal by the receiver 152, filtered by the filter 155, amplified by the amplifier circuit 156, detected by the detection circuit 157, and extracted.
[0051]
The extracted signal is compared with a criterion value from the control unit 101 by the comparison circuit 158, and it is determined whether the control unit 101 is in the double feed state or the non-multi feed state based on the comparison result. Then, the air volume of the loosening fan 135 is controlled according to the double feeding state or the non-multi feeding state.
[0052]
In addition, the control unit 101 performs control to automatically change the frequency of the ultrasonic wave and the criterion value according to the type of the transfer paper p, and also changes based on input information from the operation unit 111. There is also.
[0053]
The storage unit 102 stores transmission / reception frequencies, determination reference values, and the like, as well as the paper type name, paper maker, paper model number, and paper weight of transfer paper that may be used. I have.
[0054]
Here, the operation of this embodiment will be described with reference to the flowchart of FIG. 5 in addition to the above drawings. FIG. 5 is a flowchart mainly showing control of the control unit 101 relating to double feed detection.
[0055]
First, with the start of image formation, under the control of the control unit 101, the transfer paper p is fed out by the transport rollers 31a to 31c from any of the paper feed cassettes 30a to 30c in which the transfer paper of the designated size is stacked. Then, the paper is fed (conveyed) toward the image forming unit 50 (S1 in FIG. 5).
[0056]
At this time, the transfer paper sent out from one of the paper feed cassettes is subjected to ultrasonic transmission / reception by the double feed detection sensor 150 to detect whether it is in the double feed state or the non-multi feed state (double feed detection).
[0057]
For the first double feed detection for a certain image forming job, the control unit 101 performs transmission and reception using the initial value of the ultrasonic transmission and reception frequency stored in the storage unit 102. Further, the control unit 101 causes the comparison circuit 158 to perform comparison using the initial value of the criterion value stored in the storage unit 102.
[0058]
By this ultrasonic transmission / reception, in the non-multi feed state in which only one transfer sheet is being conveyed, the attenuation of the ultrasonic wave is small, and a reception signal larger than the judgment reference value is obtained. Further, in a multi-feed state in which two or more transfer papers are conveyed, attenuation and reflection of ultrasonic waves increase due to the influence of a plurality of transfer papers and an air layer therebetween, so that a reception signal smaller than the reference value is obtained. Can be
[0059]
If the double feeding state is detected (YES in S2 of FIG. 5), the control unit 101 turns on the separating fan 135 in the paper feed cassette from which the transfer paper for which double feeding has been detected is sent out, and controls the transfer paper. Then, the blowing for loosening is started (S3 in FIG. 5). As a result, air is fed between the transfer sheets accumulated in the sheet feeding cassette in which the double feeding state has occurred, and occurrence of further double feeding is suppressed. When a jam or the like occurs due to the double feeding state, the control unit 101 separately executes a jam process.
[0060]
When the loosening fan 135 is turned on in this way, the control unit 101 performs control to display the control state of the air volume of each of the plurality of sheet cassettes on the display unit 112. In the example shown in FIG. 6, the air volume is schematically displayed on the display of each paper feed cassette in the size selection column. Is shown.
[0061]
As a result, appropriate control of the separating fan based on the double feed detection result becomes possible in each paper feed cassette so that double feed can be suppressed. In addition, since double feed has occurred, double feed suppression control has been performed. This allows the user to know the paper feed stage in the running state.
[0062]
If the double feeding state is not detected (NO in S2 in FIG. 5), the control unit 101 keeps the separating fan 135 off (S4 in FIG. 5).
Then, with the start of image formation for the second and subsequent sheets of the image forming job being executed, under the control of the control unit 101, one of the sheet feed cassettes 30a to 30c on which transfer sheets of the designated size are stacked. Then, the transfer paper p is fed out by the transport rollers 31a to 31c, and is fed (transported) to the image forming unit 50 (S5 in FIG. 5).
[0063]
In the same manner, the transfer paper sent from the paper feed cassette is subjected to ultrasonic transmission / reception by the double feed detection sensor 150 to detect the double feed state or the non-double feed state (double feed detection).
[0064]
If the double feed state is detected (YES in S6 in FIG. 5), the control unit 101 increases the air volume of the separating fan 135 in the paper feed cassette from which the transfer paper in which the double feed was detected is sent (S7 in FIG. 5). . As a result, more air is fed between the transfer sheets accumulated in the sheet feeding cassette in which the double feeding state occurs in the same job, and the occurrence of further double feeding is suppressed.
[0065]
When the air volume of the separating fan 135 is increased in this way, the control unit 101 performs control to display the control state of the air volume of each of the plurality of sheet cassettes on the display unit 112.
[0066]
In the example shown in FIG. 6, the first-stage A3 size (recycled paper) transfer paper shows a state where the air volume is increased to 2, and the fourth-stage A3 size transfer paper is enhanced to the air volume 4. Is shown.
[0067]
As a result, appropriate control of the separating fan based on the double feed detection result becomes possible in each paper feed cassette so that double feed can be suppressed. In addition, since double feed has occurred, double feed suppression control has been performed. This allows the user to know the paper feed stage in the running state.
[0068]
If the double feeding state is not detected (NO in S6 in FIG. 5), the control unit 101 performs control to maintain the air volume of the separating fan 135 (S8 in FIG. 5). This is because it is necessary to continue the separating air blowing for the transfer sheets stored in the sheet cassette in which the double feeding state has occurred even once in the same job.
[0069]
Then, the processes in steps S5 to S7 and S8 are continued until the image forming job being executed is completed (NO in FIG. S9 → S5).
As a result of the processing described above, appropriate control of the separating fan based on the double feed detection result becomes possible in each paper feed cassette, and not only can it be possible to suppress double feed, but also because double feed has occurred. The user can know the paper feed stage in the state where the double feed suppression control is being performed. For this reason, the user can know that the multi-feed is frequently occurring in the paper cassette where the air volume is the maximum, and it is possible to replace the transfer paper in the paper cassette as needed. Become.
[0070]
In addition, although the example of the stage from 0 to 4 of the air volume was shown here, it is not limited to this.
According to the experiment of the inventor of the present invention, in the case of A4 size transfer paper, the air volume 1 is 0.48 m / s, the air volume 2 is 0.6 m / s, and the air volume 3 is the wind speed. Good results were obtained at 0.8 m / s and a wind speed of 0.96 m / s as the air volume 4.
[0071]
In the case of A3 size transfer paper, the air volume 1 is a wind speed of 0.6 m / s, the air volume 2 is a wind speed of 0.72 m / s, the air volume 3 is a wind speed of 0.96 m / s, and the air volume is 4 Good results were obtained at a wind speed of 1.1 m / s.
[0072]
In this embodiment, the control unit 101 can execute control to change the ultrasonic transmission / reception frequency of the double feed detection sensor 150 and the criterion value used for comparison by the comparison circuit 158 when double feed is detected. preferable.
[0073]
For example, a plurality of ultrasonic waves in a state where the ultrasonic transmission / reception frequency is changed are transmitted to the transfer paper being transported, and the ultrasonic transmission / reception frequency or the determination reference value is determined based on the signal level of the ultrasonic wave that has passed through the transfer paper. It is also preferable that the control means 101 can execute the control for changing.
[0074]
In this case, the control unit 101 monitors the signal level of the detection output of the detection circuit 157 in a state where the transmission / reception frequency is changed, and selects a transmission / reception frequency that increases the signal level, thereby improving the S / N ratio and increasing accuracy. Double feed detection becomes possible. In addition, when the frequency is selected as described above, the signal level of the detection output fluctuates. Therefore, it is desirable that the criterion value can be changed. In this manner, double feed detection with higher accuracy can be performed. By changing the transmission / reception frequency and the criterion value in this way, the multi-feed can be accurately performed without being affected by the paper type, that is, the difference in the ultrasonic transmission and reflection characteristics due to the paper type, paper thickness, material, surface finish, etc. It becomes possible to detect.
[0075]
In addition, the change of the ultrasonic transmission / reception frequency or the determination reference value may be selected not only by referring to the signal level of the detection output in the non-multi-feed state but also by referring to the signal level of the detection output in the multi-feed state. desirable. That is, it is desirable to make the difference between the signal levels of the detection output in the double feed state and the non-multi feed state as large as possible for accurate detection.
[0076]
As described above, regarding the ultrasonic transmission / reception frequency or the criterion, by referring to the signal level in the multi-feeding state and also referring to the signal level in the non-multi-feeding state, the ultrasonic wave is corrected by adding a correction. This makes it possible to accurately detect double feed without being affected by the type of paper.
[0077]
In addition, according to the experiment of the inventor of the present invention, the result was obtained that the ultrasonic transmission / reception frequency is preferably selected from about 100 kHz to about 500 kHz.
[0078]
Further, it is preferable that the control unit 101 changes at least one of the ultrasonic transmission / reception frequency and the criterion value with reference to the information about the transfer paper input from the operation unit 111 for performing various inputs. As described above, by determining or correcting the ultrasonic transmission / reception frequency or the determination reference value with reference to the information input from the operation unit 111, the multi-feed can be accurately performed without being affected by the paper type using the ultrasonic waves. Can be detected at the same time.
[0079]
In this case, according to the paper type name, paper maker, paper model number, paper basis weight, etc. of the transfer paper input from the operation unit 111, the control unit 101 controls the information in the storage unit 102 (paper type name, paper The transmission / reception frequency and the judgment reference value according to the maker, paper model number, paper weight, etc. are called and the selection of the transmission / reception frequency or the judgment reference value is controlled.
[0080]
The control unit 101 refers to the paper maker name and paper model number input from the operation unit 111 to make a network connection, obtain paper thickness data from the paper maker via the Internet, You may make it select a value.
[0081]
In each of the above embodiments, it is also preferable that the control unit 101 stores the change pattern of the air volume in the storage unit 102 so that a service person or the like can refer to the change pattern. In this case, information such as the time or frequency of the air volume change due to the double feed detection, the air volume, the controlled paper feed stage, and the like are stored. This makes it possible to grasp the state of the image forming apparatus and perform appropriate maintenance.
[0082]
【The invention's effect】
As described above, according to the present invention, the following effects can be obtained.
(1) In the first invention, when the transfer paper is sent out from the paper feed cassette by the paper feed means, the transfer paper stored in the paper feed cassette is blown by the blowing means for blowing. Then, the control means controls the air volume of the blowing means with reference to the result of the double feeding detection by the double feeding detecting means. As a result, it is possible to appropriately control the blowing means (separating fan) based on the result of double feed detection, and it is possible to suppress double feed.
[0083]
(2) In the second invention, the ultrasonic wave is transmitted to the transfer paper at the time of paper feeding by the paper feeding means by the double feed detecting means, and the ultrasonic wave transmitted through the transfer paper is received, and the received ultrasonic wave is received. The multifeed of the transfer paper is detected based on the signal level of the ultrasonic wave. At this time, the control means executes control to change the ultrasonic transmission / reception frequency or the criterion of the received signal level in the multifeed detection means. I have. In this way, by changing the ultrasonic transmission / reception frequency or reception signal level judgment criteria in the double feed detection means, it is possible to accurately detect the double feed without being affected by the paper type using the ultrasonic waves. become.
[Brief description of the drawings]
FIG. 1 is a functional block diagram illustrating an electrical configuration of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a configuration diagram illustrating a mechanical configuration of the image forming apparatus according to the embodiment of the present invention;
FIG. 3 is a perspective view illustrating an arrangement of a mechanical main part of a main part of the image forming apparatus according to the embodiment of the present invention;
FIG. 4 is a functional block diagram illustrating a detailed electrical configuration of a main part of the image forming apparatus according to the embodiment of the present invention.
FIG. 5 is a flowchart illustrating an operation of the image forming apparatus according to the exemplary embodiment of the present invention.
FIG. 6 is an explanatory diagram for explaining an operation of the image forming apparatus according to the embodiment of the present invention;
[Explanation of symbols]
101 control means
110 Operation display section
111 Operation unit
112 Display
120 Image processing unit
130 Paper feed unit
135 Fan for handling
140 Print Engine
150 Double feed detection sensor

Claims (8)

A paper cassette for storing transfer paper for image formation,
Blowing means for blowing air for separating the transfer paper stored in the paper cassette,
Paper feeding means for feeding transfer paper from the paper feeding cassette;
Double feed detecting means for detecting double feed of transfer paper at the time of paper feeding by the paper feeding means,
Control means for controlling the air volume of the blower means, with reference to a double feed detection result by the double feed detection means,
An image forming apparatus comprising: Comprising a plurality of paper feed cassettes each having the blowing means,
The image forming apparatus according to claim 1, wherein: A display unit that displays a state of the image forming apparatus;
The control unit performs control to display a control state of the air volume of the blowing unit on the display unit.
The image forming apparatus according to claim 1, wherein: A display unit that displays a state of the image forming apparatus;
The air supply unit is provided in each of a plurality of paper feed cassettes,
The control unit performs control to display a control state of the air volume of each of the blowing units provided on each of the plurality of paper feed cassettes on the display unit.
The image forming apparatus according to claim 1, wherein: A paper cassette for storing transfer paper for image formation,
Paper feeding means for feeding transfer paper from the paper feeding cassette;
An ultrasonic wave is transmitted to the transfer paper at the time of paper feeding by the paper feeding unit, an ultrasonic wave transmitted through the transfer paper is received, and a double feed of the transfer paper is detected based on a signal level of the received ultrasonic wave. Double feed detection means,
A control unit that performs control to change a criterion of an ultrasonic transmission / reception frequency or a reception signal level in the double feed detection unit,
An image forming apparatus comprising: The control means transmits a plurality of ultrasonic waves in a state where the ultrasonic transmission / reception frequency is changed to the transfer paper being conveyed, and the ultrasonic transmission / reception frequency or Performing control to change at least one of the criteria,
The image forming apparatus according to claim 5, wherein: The control means transmits a plurality of ultrasonic waves in a state where the ultrasonic transmission / reception frequency is changed to the transfer paper being conveyed, and receives the ultrasonic waves which have passed through the transfer paper at the time of non-multifeed and at the time of double feed. By each signal level, control to change at least one of the ultrasonic transmission and reception frequency or the determination criterion,
The image forming apparatus according to claim 5, wherein: Equipped with an operation unit for performing various inputs,
The control unit changes at least one of the ultrasonic transmission / reception frequency or the determination criterion with reference to the information on the transfer paper input from the operation unit.
The image forming apparatus according to claim 5, wherein:

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