Patent Grant
9291963
This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2015-033132 filed Feb. 23, 2015.
The present invention relates to an image forming apparatus.
For example, when an image is formed by using an electrophotographic process, fixing processing in which a recording medium such as a film, on which a developer image is formed is heated and thus the developer image is fixed on the recording medium is performed.
Expansion or contraction may occur in the recording medium when heating and fixing are performed. If extension and contraction occur in the recording medium, extension and contraction also occur in an image which has been formed on the recording medium.
According to an aspect of the invention, there is provided an image forming apparatus including:
a fixing unit that fixes a developer image which is formed on a thermoplastic recording medium by performing fixing processing that causes the recording medium on which the developer image is formed to be heated and pressed with transportation based on plural fixation parameters;
a detection unit that detects an amount of extension and contraction which occurs in the recording medium by the fixing processing; and
a suppression unit that controls at least one of the plural fixation parameters and suppresses the amount of extension and contraction which is detected by the detection unit.
Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein:
Hereinafter, exemplary embodiments according to the invention will be described in detail with reference to the accompanying drawings.
The image forming apparatus 10 is applied in image forming processing which is performed on a recording medium having thermoplasticity such as a sheet in addition to the film 12. In the first exemplary embodiment, an example of using the long film 12 will be described, but the recording medium is not limited to having a long length and may have a sheet-like shape.
Image data of an image which will be formed on the film 12 is input to the image forming apparatus 10. The image data may be input through, for example, a communication line such as a dedicated network line or a public network line to which the image forming apparatus 10 is connected. An image reading apparatus which reads an image which is recorded on an original document may be connected to the image forming apparatus 10. An image data obtained by the image reading apparatus reading the image which is recorded on the original document may be input to the image forming apparatus 10. A storage medium reading apparatus may be connected to the image forming apparatus 10 and a known configuration may be applied. An example of the known configuration is that the storage medium reading apparatus reads image data which is stored in a storage medium and thus the image data is input to the image forming apparatus 10.
The image forming apparatus 10 includes an image forming section 14, a supply section 16, and an exit section 18. A transporting path 20 for the film 12 is formed in the image forming apparatus 10. Plural transport rolls 22 are formed to be arranged in the transporting path 20. In the first exemplary embodiment, the transporting path 20 and the transport rolls 22 function as an example of a transporting unit. In the image forming apparatus 10, at least some of the transport rolls 22 are rotatably driven and thus the film 12 is transported along the transporting path 20 at a preset transportation speed and a preset tensile strength (the transportation direction is illustrated by a direction of an arrow A).
A film roll 24 is loaded in the supply section 16. The film roll 24 is obtained by winding the long film 12 having a preset width dimension so as to have a roll shape. The supply section 16 draws the film 12 from an outer peripheral edge of the film roll 24 and transfers the drawn film 12 to the transporting path 20. Thus, the film 12 is transported to the exit section 18 from the supply section 16 along the transporting path 20 through the image forming section 14. The exit section 18 stores the film 12 which is wound so as to have a roll shape.
The image forming section 14 includes a developing section 26 and a fixing section 28. The developing section 26 forms a developer image on the film 12 in such a manner that a latent image which is formed in accordance with the image data is developed by using a developer. The fixing section 28 is provided on a downstream side of the developing section 26 and fixes the developer image which has been formed on the film 12, on the film 12. In the first exemplary embodiment, the fixing section 28 functions as an example of a fixing unit.
The image forming section 14 forms a color image on the film 12 by using developers respectively having colors of Y, M, C, and K, for example. In the following descriptions, an attached reference sign of Y indicates a component for a yellow color, an attached reference sign of M indicates a component for a magenta color, an attached reference sign of C indicates a component for a cyan color, and an attached reference sign of K indicates a component for a black color. In the following descriptions, if the colors are not required to be distinguished, attachment of the reference signs of Y, M, C, and K will be omitted.
The developing section 26 includes an image forming unit 30Y, an image forming unit 30M, an image forming unit 30C, and an image forming unit 30K, as an image forming unit 30. The image forming unit 30Y uses a developer containing a yellow toner. The image forming unit 30M uses a developer containing a magenta toner. The image forming unit 30C uses a developer containing a cyan toner. The image forming unit 30K uses a developer containing a black toner. The image forming units 30Y, 30M, 30C, and 30K are sequentially arranged in the developing section 26 along the transporting path 20.
The image forming unit 30 (30Y, 30M, 30C, and 30K) includes a photoconductor 32 (32Y, 32M, 32C, and 32K), a charging device 34 (34Y, 34M, 34C, and 34K), and an exposure device 36 (36Y, 36M, 36C, and 36K). The image forming unit 30 (30Y, 30M, 30C, and 30K) includes a developing device 38 (38Y, 38M, 38C, and 38K), a transferring device 40 (40Y, 40M, 40C, and 40K), and a cleaner 42 (42Y, 42M, 42C, and 42K).
The photoconductor 32 is formed to be cylindrical as an example, and holds an electrostatic latent image on an outer circumference surface of the photoconductor 32. The photoconductor 32 is rotated in a direction (a direction of an arrow R in
For example, the charging device 34 uses a corotron, a scorotron, or the like, and charges the outer circumference surface of the photoconductor 32 which faces the charging device 34 by applying a charged voltage which is defined in advance. The exposure device 36 scans and irradiates the charged outer circumference surface of the photoconductor 32 with, for example, a light beam.
In the image forming apparatus 10, image processing which is set in advance is performed on image data. Color separation is performed on the image data which is subjected to the image processing and thus raster data (bitmap data) for each of colors of Y, M, C, and K, for example, is generated. The exposure device 36 performing scanning of and irradiation with a light beam in accordance with the raster data under a control based on the raster data, and thus forms an electrostatic latent image corresponding to the raster data, on the photoconductor 32.
The developing device 38 uses a liquid developer or a powder developer as the developer. The developing device 38 supplies the developer to the outer circumference surface of the photoconductor 32 on which the electrostatic latent image is formed, and thus forms a developer image corresponding to the electrostatic latent image, on the outer circumference surface of the photoconductor 32. Thus, a developer image corresponding to a Y color component of the image data is formed on the photoconductor 32Y. A developer image corresponding to an M color component of the image data is formed on the photoconductor 32M. A developer image corresponding to a C color component of the image data is formed on the photoconductor 32C. A developer image corresponding to a K color component of the image data is formed on the photoconductor 32K.
The transferring device 40 includes an intermediate transfer roll 44 (44Y, 44M, 44C, and 44K) and a transfer roll 46 (46Y, 46M, 46C, and 46K). The intermediate transfer roll 44 is drivenly rotated by rotation of the photoconductor 32 in a state where an outer circumference surface of the intermediate transfer roll 44 comes into contact with the outer circumference surface of the photoconductor 32 at a preset position (primary transfer position) on a downstream side of the developing device 38 in the rotation direction of the photoconductor 32. The intermediate transfer roll 44 is disposed such that the outer circumference surface of the intermediate transfer roll 44 comes into contact with the film 12 which is transported along the transporting path 20, at a secondary transfer position on an opposite side of the primary transfer position. The transfer roll 46 is disposed to face the intermediate transfer roll 44 with the transporting path 20 interposed between the transfer roll 46 and the intermediate transfer roll 44 at the secondary transfer position. The transfer roll 46 is rotated (rotated in a direction of an arrow R) such that the film 12 which has been transported along the transporting path 20 is sent out in a state where the film 12 is interposed between the transfer roll 46 and the intermediate transfer roll 44.
In the image forming unit 30, a primary transfer voltage is applied to the intermediate transfer roll 44 from a power supply device (not illustrated) and thus a toner image which is formed on the photoconductor 32 is primarily transferred to the outer circumference surface of the intermediate transfer roll 44 at the primary transfer position. In the image forming unit 30, a secondary transfer voltage is applied to the transfer roll 46 from the power supply device (not illustrated), and thus the toner image which has been transferred to the intermediate transfer roll 44 is transferred onto the film 12 at the secondary transfer position.
In the developing section 26, the developer images of colors which are respectively formed by the image forming units 30Y, 30M, 30C, and 30K are transferred to be sequentially stacked on the film 12, and thus a developer image (color developer image) corresponding to the image data is formed on the film 12 as a developer image. The cleaner 42 removes residual developers from the outer circumference surface of the photoconductor 32 in which primary transfer is complete. Secondary transfer is complete in the intermediate transfer roll 44 and then a cleaner 48 (48Y, 48M, 48C, and 48K) removes residual developers from the outer circumference surface of the intermediate transfer roll 44.
A fixation control program is included as the control program which is executed by the CPU of the computer included in the control section 58. Thus, the CPU executes the fixation control program and thus the computer functions as the fixation control section 56.
A fixing controller 60 is provided in the fixation control section 56. In the first exemplary embodiment, the fixing controller 60 includes a function as the fixing unit and functions as an example of a suppression unit. In the first exemplary embodiment, as an example, the heater 54 is provided in each of the fixing roll 50 and the pressure roll 52. These heaters 54 are connected to the fixing controller 60. A temperature sensor 62 is connected to the fixing controller 60. The temperature sensor 62 detects, for example, the temperature of the outer circumference surface of the fixing roll 50 in a non-contact manner.
Fixation parameters when an image is formed on the film 12 through the electrophotographic process include a fixation temperature, a fixation pressure, a transportation speed of the film 12, a tensile strength (tension) applied to the film 12, and the like. The fixing controller 60 sets the fixation temperature among the fixation parameters, and controls an operation of the heater 54 based on the fixation temperature which has been set, such that the temperature of the outer circumference surface of the fixing roll 50 which is detected by the temperature sensor 62 is held to be the fixation temperature. The fixing section 28 may have a known configuration in which the film 12 is heated and thus the toner image is fixed on the film 12. Detailed descriptions of the fixing section 28 which includes the fixing roll 50 and the pressure roll 52 will be omitted.
As illustrated in
As illustrated in
As illustrated in
As illustrated in
In the R-encoder 72, the rotation shaft (not illustrated) is linked to the rotation shaft of one rotation roll of the rotation rolls 68 and 70 (see
Regarding the extension-and-contraction obtaining section 66 and the speed obtaining section 74, for example, a CPU of the computer included in the control section 58 of the image forming apparatus 10 executes an extension-or-contraction obtaining program and a speed obtaining program, and thus the computer functions as the extension-and-contraction obtaining section 66 and the speed obtaining section 74.
The speed obtaining section 74 is connected to the R-encoder 72 and a pulse signal is input to the speed obtaining section 74 from the R-encoder 72. The speed obtaining section 74, for example, counts the number of pulses in the pulse signal which is input from the R-encoder 72 and obtains a transportation speed Va of the film 12 which is subjected to the fixing processing, from a count value per a unit time. In the first exemplary embodiment, the transportation speed Va functions as an example of a transportation speed after the fixing processing. The speed obtaining section 74 outputs the obtained transportation speed Va of the film 12 to the extension-and-contraction obtaining section 66. In the following descriptions, the transportation speed includes a meaning of a movement speed at a certain point on the film 12.
The extension-and-contraction obtaining section 66 sets the transportation speed of the film 12 on the transporting path 20 of the image forming apparatus 10 as a transportation speed Vb of the film 12 before the fixing processing. The extension-and-contraction obtaining section 66 calculates a rate of extension and contraction Rs in the transportation direction of the film 12 after the fixing processing, based on the transportation speed Va and the transportation speed Vb. In the first exemplary embodiment, the rate of extension and contraction Rs functions as an example of an amount of extension and contraction. When no extension and contraction occur in the film 12 which is subjected to the fixing processing, there is no difference (Va=Vb) between the transportation speed of the film 12 before the fixing processing and the transportation speed of the film 12 after the fixing processing. On the contrary, for example, if the film 12 is extended by the fixing processing, the transportation speed Va of the film after the fixing processing is higher than the transportation speed Vb of the film 12 before the fixing processing (Va>Vb). The rate of extension and contraction in the transportation direction of the film 12 is obtained from, for example, a ratio of the transportation speed before the fixing processing and the transportation speed after the fixing processing (for example, Rs=((Va/Vb)−1)×100(%), extension when Rs>0, contraction when Rs<0, and no extension and contraction when Rs=0).
The long film 12 is partially extended in a longitudinal direction, whereby contraction in an extended area may occur in a width direction. The long film 12 is contracted in the longitudinal direction, whereby extension in a contracted area may occur in the width direction. The extension and contraction of the film 12 in the width direction are defined by a material of the film 12, the thickness of the film 12, and the like. However, the extension and contraction have a value corresponding to the rate of extension and contraction Rs in the transportation direction (longitudinal direction). If the extension and contraction in the film 12 occur in at least one of the longitudinal direction and the width direction, extension and contraction depending on the extension and contraction which occur in the film 12 occur in an image which is formed on the film 12.
Accordingly, it is possible to predict extension and contraction of an image which is formed on the film 12, by detecting the extension and contraction in the transportation direction of the film 12. The extension and contraction in the width direction is suppressed by suppressing the extension and contraction in the film 12 in the transportation direction. Occurrence of the extension and contraction in an image which is formed on the film 12 is suppressed by suppressing the extension and contraction of the film 12.
Here, the extension and contraction by the fixing processing in the transportation direction of the film 12 vary depending on the fixation temperature, the fixation pressure, the transportation speed of the film 12, the tensile strength (tension) which is applied to the film 12, and the like. As described above, in the image forming apparatus 10, the transportation speed of the film 12 and the tensile strength applied to the film 12 are set in advance, and the film 12 is transported at the transportation speed which has been set, in a state where the tensile strength which has been set is applied. In the fixing section 28 of the image forming apparatus 10, the fixation pressure which has been set in advance is applied to the film 12 by using a pressing mechanism which is provided in the pressure roll 52. For this reason, in the image forming apparatus 10, the fixation temperature is used as an example of the fixation parameter for suppressing the extension and contraction which occur in the film 12, and the extension and contraction of the film 12 are suppressed by suppressing the fixation temperature in the fixing section 28.
In the image forming apparatus 10, regarding of the film 12 of the film roll 24 which is loaded in the supply section 16, variation in the rate of extension and contraction Rs for a temperature variation (temperature ΔT) in the fixation temperature Tf is obtained in advance and stored in a storage unit such as a non-volatile memory (not illustrated). The fixing controller 60 receives the rate of extension and contraction Rs of the film 12 which is input from the extension-and-contraction obtaining section 66. Thus, the fixing controller 60 sets a correction value (temperature ΔT) of the fixation temperature Tf which is the fixation parameter which causes the extension and contraction of the film 12 to be suppressed, in accordance with the input rate of extension and contraction Rs. The fixing controller 60 performs the fixing processing on the film 12 in such a manner that the fixation temperature Tf is corrected based on the correction value which has been set, and heating of the heater 54 is controlled based on the corrected fixation temperature Tf.
Next, correction processing of the fixation temperature Tf which is one of the fixation parameters will be described as effects of the first exemplary embodiment. In the image forming apparatus 10, the film 12 is extracted from the film roll 24 which is loaded in the supply section 16, and an toner image corresponding to image data is transferred onto the film 12 while the extracted film 12 is transported. In the image forming apparatus 10, when the film 12 onto which the toner image is transferred passes through the fixing section 28, the film 12 is heated and pressed. Thus, the toner image is melted and fixed on the film 12 and an image corresponding to the image data is formed.
The film 12 which is subjected to the fixing processing is heated and softened, and thus the extension and contraction easily occur. That is, the film 12 is heated in a state where tension is applied, and thus is easily extended in the transportation direction and contraction in the width direction easily occurs with extension of the film 12. Occurrence of the extension and contraction in the film 12 causes extension and contraction to occur in an image which is formed on the film 12. Thus, the image which is formed on the film 12, and finish of the film 12 on which the image is formed are damaged. Here, the fixation control section 56 which is provided in the image forming apparatus 10 suppresses the extension and contraction of the film 12, and thus attempts suppression of the extension and contraction of the image which is formed on the film 12.
In a flowchart of
In Step 202, the transportation speed of the film 12 which is set in the image forming apparatus 10 is obtained as the transportation speed Vb of the film 12 before the fixing processing, and the rate of extension and contraction Rs in the transportation direction of the film 12 is obtained based on the transportation speeds Va and Vb. The rate of extension and contraction Rs of the film 12 in the transportation direction is obtained by detecting the extension and contraction of the film 12 in the transportation direction. The extension and contraction of an image which will be formed on the film 12 is predicted from the rate of extension and contraction Rs.
In Step 204, it is determined whether or not the extension and contraction occurring in an image which is formed on the film 12 is in an allowable range, based on the rate of extension and contraction Rs of the film 12 in the transportation direction. For example, in the image forming apparatus 10, the allowable range of the extension and contraction for an image which is formed on the film 12 is defined, and an allowable range (for example, an upper limit value Rc) of the rate of extension and contraction Rs of the film 12 in the transportation direction is set in accordance with the allowable range. In Step 204, it is determined whether or not the obtained rate of extension and contraction Rs of the film 12 are in the preset allowable range (−Rc≦Rs≦Rc).
Here, if the rate of extension and contraction Rs of the film 12 in the transportation direction is in the preset allowable range, it is determined to be Yes in Step 204 and the processing is ended without correction of the fixation temperature Tf.
On the contrary, if the obtained rate of extension and contraction Rs of the film 12 in the transportation direction exceeds the allowable range (for example, Rs<−Rc or Rc<Rs), it is determined to be No in Step 204 and the process proceeds to Step 206. In Step 206, the temperature ΔT (variation amount of the temperature) which is necessary to cause the rate of extension and contraction Rs of the film 12 in the transportation direction to be in the allowable range is set as the correction value of the fixation temperature Tf based on variation of the rate of extension and contraction Rs for variation of the temperature which is set regarding of the film 12.
Then, in Step 208, the fixation temperature Tf is corrected based on the correction value (temperature ΔT) which has been set, and an update is performed such that the corrected fixation temperature Tf is set as a new fixation temperature Tf (Step 210). Thus, in the fixing section 28, the fixing processing is performed on the film 12 based on the updated fixation temperature Tf. Accordingly, in the image forming apparatus 10, the extension and contraction of the film 12 by the fixing processing is suppressed, and the extension and contraction of an image which is formed on the film 12 is suppressed.
Next, the second exemplary embodiment will be described. In the second exemplary embodiment, functional components which are equivalent to those in the first exemplary embodiment are denoted by the reference signs which are applied to the first exemplary embodiment, and detailed descriptions thereof will be omitted.
The photoelectric sensor 76 includes a light emitting device 78A and a light receiving device 78B. The light emitting device 78A is disposed to face one surface (for example, a surface) of the film 12, and the light receiving device 78B is disposed to face another surface of the film 12. The light emitting device 78A emits light in a preset range along the width direction of the film 12. The light receiving device 78B receives the light which is emitted from the light emitting device 78A in the preset range along the width direction of the film 12. Here, a portion of light which is emitted from the light emitting device 78A is blocked at an end portion of the film 12, and thus a light reception amount of the light receiving device 78B is reduced. In the photoelectric sensor 76, for example, a position of a tip end of the film 12 in the width direction is specified based on the reduced light reception amount of the light receiving device 78B. In the second exemplary embodiment, an example in which the position of the tip end of the film 12 in the width direction is specified based on variation in the light reception amount of the light receiving device 78B will be described. However, the configuration of the photoelectric sensor 76 is not limited thereto. For example, any known configuration may be applied in the photoelectric sensor 76. An example of the known configuration is that a light receiving device in which plural light reception elements are arranged in the width direction of the film 12 is used instead of the light receiving device 78B, and a tip end position of the film 12 in the width direction is specified based on a position of the light reception element which has a reduced light reception amount.
The photoelectric sensors 76L and 76R face tip end portions of the film 12 which is subjected to the fixing processing on both sides in the width direction and a distance D between the photoelectric sensors 76L and 76R (for example, distance between center positions of a measurement range in the width direction) is set in advance. With this, in the fixing section 28A, a dimension (below referred to as a width dimension Wa) in the width direction of the film 12 after the fixing processing is obtained from tip end positions of the film 12 in the width direction, which are respectively detected by the photoelectric sensors 76L and 76R.
As illustrated in
The speed detection section 86 includes a speed obtaining section 92, the R-encoder 72, and an R-encoder 94. In the second exemplary embodiment, the R-encoder 72 is connected to the speed obtaining section 92, and thus the speed obtaining section 92 functions as an example of the first speed detection unit. Further, the R-encoder 94 is connected to the speed obtaining section 92, and thus the speed obtaining section 92 functions as an example of a second speed detection unit.
The R-encoder 94 is linked to a rotation shaft 80A of the rotation roll 80 (see
The width detection section 88 includes the photoelectric sensors 76L and 76R, and a width obtaining section 96. In the second exemplary embodiment, the width detection section 88 functions as an example of the first width detection unit. The width obtaining section 96 obtains the width dimension Wa of the film 12 after the fixing processing from the tip end positions of the film 12 in the width direction, which are respectively detected by the photoelectric sensors 76L and 76R.
The extension-and-contraction obtaining section 90 obtains the rate of extension and contraction Rs of the film 12 after the fixing processing in the transportation direction, based on the transportation speeds Va and Vb of the film 12 which are obtained by the speed obtaining section 92. The extension-and-contraction obtaining section 90 uses a width dimension of the film roll 24 which is loaded in the supply section 16 as a width dimension Wb of the film 12 before the fixing processing. The extension-and-contraction obtaining section 90 obtains a rate of extension and contraction Rw of the film 12 after the fixing processing in the width direction, based on the width dimension Wa of the film 12 after the fixing processing, which is obtained by the width obtaining section 96, and the width dimension Wb. In the second exemplary embodiment, each of the rates of extension and contraction Rs and Rw functions as an example of the amount of extension and contraction. The rate of extension and contraction Rw of the film 12 in the width direction is obtained, for example, based on a ratio of the width dimensions (for example, Rw=((Wa/Wb)−1)×100(%), extension when Rw>0, and contraction when Rw<0). The rate of extension and contraction Rs and the rate of extension and contraction Rw are obtained, and thus the extension and contraction of an image which is formed on the film 12 in the transportation direction of the film 12 and in the width direction of the film 12 are predicted.
The fixing controller 84 sets the correction value of the fixation temperature Tf such that the extension and contraction of an image which is formed on the film 12 are in an allowable range which is set in advance. Data (for example, a table) regarding of variation in the rate of extension and contraction Rs of the film 12 in the transportation direction and variation in the rate of extension and contraction Rw of the film 12 in the width direction for temperature variation (temperature ΔT) in the fixation temperature is obtained in advance and stored in the fixing controller 84. The fixing controller 84 corrects the fixation temperature Tf based on the table which is stored in advance such that each of the rate of extension and contraction Rs of the film 12 in the transportation direction and the rate of extension and contraction Rw of the film 12 in the width direction is in the preset allowable range. When a correction value which is obtained from the rate of extension and contraction Rs is different from a correction value which is obtained from the rate of extension and contraction Rw, any one of the correction values may be used and an average value of the correction values may be used.
The fixing controller 84 controls the heater 54 such that the outer circumference surface of the fixing roll 50 has the corrected fixation temperature Tf, whereby the fixing processing is performed. Accordingly, the film 12 which is subjected to the fixing processing by the fixing section 28A, and an image which is formed on the film 12 have the suppressed extension and contraction in the transportation direction and in the width direction.
In the second exemplary embodiment, the rotation roll 80 and the R-encoder 94 are provided so as to detect the transportation speed Vb before the fixing processing. However, the transportation speed Vb before the fixing processing may be detected by using the transportation speed of the film 12 which is set on the transporting path 20 of the image forming apparatus 10. The photoelectric sensor 76 (76L and 76R) which functions as a second width detection unit may be provided on the upstream side of the fixing roll 50 and the pressure roll 52, and the width dimension Wb may be obtained from a detection result of the photoelectric sensor 76 which is provided on the upstream side.
In the second exemplary embodiment, a case where the photoelectric sensor 76 for detecting the width dimension in a manner of non-contact with the film 12 is used as an example of the first and the second width detection units is described, but it is not limited thereto. For example, a width detection unit having a contact type configuration or a non-contact type configuration which is well known may be applied as the first and the second width detection units. An example of the known configuration is that a contact type edge sensor is provided so as to face both ends of the film 12 in the width direction.
Next, the third exemplary embodiment will be described. In the third exemplary embodiment, functional components which are equivalent to those in the first exemplary embodiment or the second exemplary embodiment are denoted by the reference signs which are applied to the first exemplary embodiment or the second exemplary embodiment, and detailed descriptions thereof will be omitted.
As illustrated in
As illustrated in
As the light receiving device 110, an optical detection element such as a photodiode and a photo-transistor may be used. The light receiving device 110 receives a reflected beam Ls1 of the laser beam L1 and a reflected beam Ls2 of the laser beam L2 which are scattered and reflected on the surface of the film 12. At this time, the reflected beams Ls1 and Ls2 which are received by the light receiving device 110 have an angle of φ/2 which is an angle of optical axes of the laser beams L1 and L2.
Here, the Doppler effect occurs in the reflected beams Ls1 and Ls2 which are reflected by the film 12. One of a frequency Fs1 of the reflected beam Ls1 and a frequency of Fs2 of the reflected beam Ls2 varies (increases) in a positive direction in accordance with a movement speed of the film 12, and another varies (reduces) in a negative direction in accordance with the movement speed. Accordingly, a frequency Fd of a laser beam which is received by the light receiving device 110 is indicated as follows.
Fd=|Fs1−Fs2|
If the movement speed of the film 12 is set as v, and an angle of the film 12 to a vertical line of the optical axes of the reflected beams Ls1 and Ls2 which are reflected toward the light receiving device 110 is set as an inclination angle θ, the frequency Fd is obtained as follows.
Fd=(2v/λ)·sin(φ/2)·cos θ
Accordingly, the light receiving device 110 receives the reflected beams Ls1 and Ls2, and heterodyne detection is performed on the reflected beams Ls1 and Ls2, whereby an electrical signal having the frequency Fd corresponding to the transportation speed v of the film 12 is obtained and the transportation speed v of the film 12 is obtained from the obtained electrical signal. Accordingly, the speedometer 102 is provided so as to face the surface of the film 12 after the fixing processing, whereby an electrical signal having the frequency Fd corresponding to the transportation speed Va of the film 12 after the fixing processing is output from the speedometer 102.
As illustrated in
In the fixing section 28B according to the third exemplary embodiment, the transportation speed Va of the film 12 after the fixing processing is measured with high accuracy in a state where there is no contact with the film 12. Accordingly, in the fixing section 28B, the fixation temperature Tf is corrected based on the measured transportation speed Va, and the extension and contraction of the film 12 after the fixing processing and the extension and contraction of an image which is formed on the film 12 are suppressed.
Thus, in the fixing section 28C, not only the transportation speed Va of the film 12 after the fixing processing is obtained by the speedometer 102A and also the transportation speed Vb of the film 12 before the fixing processing is obtained by the speedometer 102B. In the fixing section 28C, the fixation temperature Tf is corrected based on the transportation speed Va of the film 12 after the fixing processing, which is obtained by the speedometer 102A and the transportation speed Vb of the film 12 before the fixing processing, which is obtained by the speedometer 102B. Accordingly, in the fixing section 28C, the extension and contraction which occur in the film 12 after the fixing processing, and the extension and contraction of an image which is formed on the film 12 are suppressed.
In the fixing section 28C, a width detection unit such as the photoelectric sensor 76 (76L and 76R) which functions as an example of the first width detection unit may be disposed on a downstream side of the fixing roll 50 and the pressure roll 52 (for example, a downstream side of the speedometer 102A in the transportation direction of the film 12). In the fixing section 28C, a width detection unit such as the photoelectric sensor 76 (76L and 76R) which functions as an example of the second width detection unit may be disposed on the upstream side of the fixing roll 50 and the pressure roll 52 (for example, an upstream side of the speedometer 102B in the transportation direction of the film 12). The fixing section 28C may correct the width dimension Wa which is detected by the width detection unit such as the photoelectric sensor 76, or the fixation temperature Tf including the rate of extension and contraction Rw of the film 12 in the width direction which is obtained from the width dimension Wa and the width dimension Wb.
Next, the fourth exemplary embodiment will be described. In the fourth exemplary embodiment, functional components which are equivalent to those in the first, the second, or the third exemplary embodiments are denoted by the reference signs which are applied to the first, the second, or the third exemplary embodiments, and detailed descriptions thereof will be omitted.
The image processing section 122 performs an image processing which has been set in advance, for image data. The image processing section 122 performs color separation on the image data which is subjected to the image processing, and thus generates raster data for each color of Y, M, C, and K, for example. The exposure control section 124 controls the exposure device 36 (36Y, 36M, 36C, and 36K) which is provided in the image forming unit 30, based on the raster data for each color which is generated by the image processing section 122. Accordingly, a developer image corresponding to the image data is formed on the film 12.
The fixation control section 126 includes the fixing controller 84, a detection section 128, and an extension-and-contraction obtaining section 130. In the fourth exemplary embodiment, the fixing controller 84 functions as the fixing unit, and functions as an example of the suppression unit. The detection section 128 and the extension-and-contraction obtaining section 130 function as an example of the detection unit. The detection section 128 includes an imaging sensor 132 and an image obtaining section 134. In the fourth exemplary embodiment, the imaging sensor 132 and the image obtaining section 134 function as an example of the image reading unit.
As illustrated in
Here, a preset area of the film 12 on which an image is formed may be used, for example, cut out in post-processing after image formation, and the preset area includes an image area. Accordingly, in this case, both end portions in the width direction and a preset area in the transportation direction are set as an unuse area.
Thus, in the fourth exemplary embodiment, an indicator is formed in a preset area such as the unuse area of the film 12 and the imaging sensor 132 reads the preset area on the film 12 including the formed indicator. Image data of an indicator is stored in a storage unit (not illustrated) of the image processing section 122 illustrated in
The imaging sensor 132 is connected to the image obtaining section 134. The image obtaining section 134 reads an area including an image of the indicator which is formed on the film 12 by the imaging sensor 132. The image obtaining section 134 obtains a dimension on the film 12, which is set in advance in order to detect the amount of extension and contraction of the film 12, from the area including the image of the indicator, which is read from the film 12. The extension-and-contraction obtaining section 130 obtains the rate of extension and contraction Rs and the rate of extension and contraction Rw in the transportation direction of the film 12, based on the dimension obtained by the image obtaining section 134. In the fourth exemplary embodiment, each of the rates of extension and contraction Rs and Rw functions as an example of the amount of extension and contraction. The fixing controller 84 corrects the fixation temperature Tf based on the rates of extension and contraction Rs and Rw which are obtained by the extension-and-contraction obtaining section 130.
The mark 136 is formed as a developer image on the film 12 such that a height which is a distance between the vertex P and the base 138C becomes a preset height h0, and a width dimension which is the length of the base 138C becomes a preset width dimension w0. The developer image of the mark 136 is formed on the film 12 such that the vertex P is positioned on a downstream side of the film 12 in the transportation direction and the line of symmetry is positioned along the transportation direction.
In the fourth exemplary embodiment, as an example, the mark 136 is formed at both of the end portions of the film 12 in the width direction such that a distance between vertices P becomes a preset distance D0. In the fourth exemplary embodiment, as an example, the mark 136 is formed such that a distance in the transportation direction of the film 12 between vertices P becomes a preset distance L0. In the fourth exemplary embodiment, the distance L0 functions as an example of a transportation direction dimension between indicators and the distance D0 functions as an example of a width direction dimension between the indicators. When the marks 136 at both of the end portions of the film in the width direction are required to be distinguished, one mark is set as a mark 136L, and another mark is set as a mark 136R. The mark 136 is formed by using any one color of Y, M, C, and K, or using at least two colors of Y, M, C, and K. When the image forming apparatus includes an image forming unit for a color which is different from Y, M, C, and K, the mark 136 may be formed by using the color of the image forming unit.
When the marks 136L and 136R which are formed at both of the end portions of the film 12 in the width direction are detected, the image obtaining section 134 obtains a distance Ds between a vertex P of the mark 136L and a vertex P of the mark 136R from the image data which is read by the imaging sensor 132. If the image obtaining section 134 detects the mark 136 (136A or 136B), and then detects the next mark 136, the image obtaining section 134 obtains a distance Ls between a vertex P of the mark 136 which is detected for the first time, and a vertex P of the mark 136 which is detected next. The number of pixels in image data or the like may be used for the distance Ds and the distance Ls.
The distance Ds which is obtained by the image obtaining section 134 corresponds to the distance D0 between the vertices P of the marks 136L and 136R which are formed at both of the end portions of the film 12 before the fixing processing in the width direction. The distance Ls corresponds to the distance L0 between vertices P of two marks 136 which are adjacent to each other in the transportation direction.
The extension-and-contraction obtaining section 130 illustrated in
The fixing controller 84 corrects the fixation temperature based on the rate of extension and contraction Rs and the rate of extension and contraction Rw which are obtained by the extension-and-contraction obtaining section 130. Thus, in the fixing section 28D, the fixation temperature Tf is corrected in accordance with the extension and contraction which occur in the film 12. The extension and contraction of the film 12 after the fixing processing and the extension and contraction of an image which is formed on the film 12 are suppressed.
In the fourth exemplary embodiment, the marks 136L and 136R which are formed at both of the end portions of the film 12 in the width direction, and at least two marks 136 which are formed in the transportation direction are used, but it is not limited thereto. For example, the mark 136 is formed to have the height h0 and the width dimension w0 which are defined in advance. For this reason, the height h and the width dimension w of one mark 136 may be detected and the rates of extension and contraction Rs and Rw may be obtained from the height h and the width dimension w which are detected.
The marks 136 may be formed in positions which are set in advance in the width direction, such as one end portion of the film 12 in the width direction, at the preset distance L0 in the transportation direction. The fixation temperature Tf may be corrected by using the rate of extension and contraction Rs which is obtained from at least two marks 136.
In the fourth exemplary embodiment, the mark 136 is used as an indicator which is used for speed detection. However, the indicator is not limited to the mark 136, and may use an image having any shape. For example, so-called dragonflies may be formed at a preset position of the film 12 in the width direction on the film 12 on which an image is formed, with a preset distance in the transportation direction of the film 12. The so-called dragonfly is an indicator having a cross shape, an L-shape, or a T-shape which is used in estimation and match of the image which is formed on the film 12. A dragonfly and the like for estimation and match may be used in detection of the amount of extension and contraction of the film 12.
In the fourth exemplary embodiment, the imaging sensor 132 is provided on the downstream side of the fixing roll 50 and the pressure roll 52 so as to read the mark 136 on the film 12 which is subjected to the fixing processing. However, the position of the imaging sensor 132 is not limited thereto. For example, the imaging sensor 132 may be also disposed on the upstream side of the fixing roll 50 and the pressure roll 52 and read the mark 136 before the fixing processing. Thus, a distance between the marks 136 before the fixing processing in the transportation direction, and a distance between the marks 136 before the fixing processing in the width direction may be obtained. With this, the distance between the marks 136 in the transportation direction and the distance between the marks 136 in the width direction before and after the fixing processing are obtained, and the extension and contraction which occur in the film 12 are detected based on the obtained distances with high accuracy.
As described above, in the first to the fourth exemplary embodiments, the amount of extension and contraction of the film 12 after the fixing processing is obtained, and the fixation temperature is corrected such that the rate of extension and contraction of the film 12 in the transportation direction, which is obtained from the amount of extension and contraction is suppressed. With this, the extension and contraction of an image which is formed on the film 12 is suppressed. The extension and contraction occurring in the film 12 is also suppressed.
In the second exemplary embodiment, the transportation speed Vb of the film 12 before the fixing processing is obtained in addition to the transportation speed Va of the film 12 after the fixing processing, and the fixation temperature is corrected such that the extension and contraction of the film 12 in the transportation direction which are obtained based on the transportation speeds Va and Vb are suppressed. With this, the fixation temperature is corrected more accurately than a case where only the transportation speed Va is detected and occurrence of the extension and contraction of an image which is formed on the film 12 and occurrence of the extension and contraction of the film 12 on which an image is formed is suppressed.
In the exemplary embodiments, the extension and contraction of the film 12 are suppressed in accordance with the extension and contraction occurring in the film 12. Further, the extension and contraction occurring in the film 12 in addition to an image which is formed on the film 12 are suppressed. Accordingly, for example, even though the film 12 is divided by a preset size and thus an image which is formed on the film 12 is cut out, occurrence of poor finish such as a shift of a position of an image in an area obtained by cutting out the film 12 is prevented.
In the above-described exemplary embodiments, the fixation temperature is used as the fixation parameter and the fixation temperature is corrected. Thus, occurrence of the extension and contraction in a recording medium such as the film 12 is suppressed. However, it is not limited to the fixation temperature, and any fixation parameter may be used. As the fixation parameter, the fixation temperature, the fixation pressure, the transportation speed of the film 12, the tensile strength (tension) which is applied to the film 12, and the like may be used. Thus, at least one fixation parameter among these fixation parameters may be used for correction. For example, regarding of the fixation pressure, a configuration and the like in which a pressure adjustment mechanism is provided in the pressure roll 52, and thus pressure in accordance with the amount of extension and contraction which is detected from the film 12 is adjusted may be applied. Regarding of the transportation speed and the tensile strength, a configuration and the like in which a buffer section is provided on the upstream side of the fixing section, the buffer section causes transportation of the film to the fixing section to be temporarily delayed, and at least one of a speed adjustment section for adjusting the transportation speed and a tensile strength adjustment section for adjusting tensile strength is provided on a downstream side of the buffer section may be applied.
The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-033132 | Feb 2015 | JP | national |
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