JP2013241253A - Image forming apparatus, method for detecting thickness of recording medium, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of detecting thickness of a recording medium without prolonging time from the start of an image forming operation to the printing and output of an image.SOLUTION: An image forming apparatus includes: a conveyance means for conveying a recording medium in the state of sandwiching the recording medium between a driving roller and a driven roller pressed by the driving roller and rotated in a driven manner; a position detecting means for outputting a value indicating a position of the driven roller in the direction of contact with/separation from the driving roller; a thickness detecting means for acquiring the value, which is output from the position detecting means during the non-conveyance of the recording medium, as a reference value and for detecting the thickness of the recording medium on the basis of a difference between the reference value and the value output by the output from the position detecting means during the conveyance of the recording medium; and an adjusting operation detecting means for detecting that an adjusting operation is performed in an image forming part for forming an image on the recording medium. The thickness detecting means obtains the reference value when the adjusting operation detecting means detects that the adjusting operation of the image forming part is performed.

Description

  The present invention relates to an image forming apparatus, a recording medium thickness detection method, and a program.

  A variety of recording media may be used in image forming apparatuses such as printers and copiers. In order to always output an image of a certain quality, the type, size, thickness, etc. of the recording medium used It is preferable to form and output an image under corresponding image forming conditions. For example, in an image forming apparatus that forms an image by an electrophotographic method, it is necessary to optimize transfer conditions and fixing conditions according to the thickness of the recording medium, and the thickness of the recording medium is reduced before forming an image on the recording medium. It is desirable to know.

  In view of this, it has a conveying means for nipping and conveying the recording medium between the driving roller and a driven roller that is driven and rotated by the driving roller, and is driven when the conveying means conveys the recording medium and when it does not convey the recording medium. There is known an image forming apparatus that detects a position of a roller and acquires a difference between the detected positions as a thickness of a recording medium (see, for example, Patent Document 1).

  However, in the image forming apparatus according to Patent Document 1, it takes time to detect the position of the driven roller when the recording medium is not conveyed every time an image is formed in order to detect the thickness of the recording medium. There is a possibility that the time from when the image forming operation is started to when the image is printed and output becomes longer.

  The present invention has been made in view of the above, and it is possible to detect the thickness of a recording medium without extending the time from the start of an image forming operation to the printing and output of the image. An object is to provide a forming apparatus.

  According to the image forming apparatus of one aspect of the present invention, the conveying unit that holds and conveys the recording medium between the driving roller and the driven roller that is pressed by the driving roller and driven to rotate, and the driving roller are in contact with and separated from the driving roller. Position detection means for outputting a value indicating the position of the driven roller in the direction, and a value output from the position detection means when the recording medium is not transported is obtained as a reference value, and the position detection is performed when the recording medium is transported Based on the difference between the value output from the means and the reference value, the thickness detecting means for detecting the thickness of the recording medium and the image forming unit for forming an image on the recording medium perform adjustment operations. An adjustment operation detecting unit that detects that the adjustment value is detected when the adjustment operation detecting unit detects that the adjustment operation of the image forming unit is being performed. To get.

  According to the embodiment of the present invention, it is possible to provide an image forming apparatus capable of detecting the thickness of a recording medium without extending the time from the start of an image forming operation to the printing and output of an image. .

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment. 1 is a diagram illustrating a hardware configuration of an image forming apparatus according to an embodiment. 3 is a block diagram illustrating a functional configuration for detecting a sheet thickness in the image forming apparatus according to the embodiment. FIG. It is a figure which illustrates the composition of the conveyance part and detection sensor concerning an embodiment. It is a figure which shows the example of an output of the detection sensor which concerns on embodiment. It is a figure which shows the example which averaged the output of the detection sensor which concerns on embodiment. 6 is a diagram illustrating a flowchart of a sheet thickness detection process during image formation of the image forming apparatus according to the embodiment. FIG. It is a figure which illustrates the flowchart of the process in which the thickness detection part in embodiment acquires a reference value. It is a figure which illustrates the flowchart of the reference value acquisition process by the thickness detection part in embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

<Configuration of image forming apparatus>
First, a schematic configuration of the image forming apparatus 100 according to the embodiment will be described with reference to FIG.

  The image forming apparatus 100 includes a photoconductor 10, a charging device 11, an exposure device 12, a developing device 13, an intermediate transfer belt 20, a secondary transfer roller 30, a fixing device 40, an automatic document feeder (ADF) 50, a reading device 51, and the like. Is provided. The image forming apparatus 100 includes a plurality of developing units including a photoconductor 10 that forms toner images of different colors, a charging device 11, an exposure device 12, and a developing device 13, and is a recording medium stored in a paper tray 60. Is a multi-function machine that prints and outputs a color image on paper P.

  In the image forming apparatus 100, when printing an image on the paper P, first, the charging device 11 uniformly charges the surface of the rotating photoreceptor 10, and for example, the reading device 51 reads a document set on the ADF 50. Based on the image data and the like, the exposure device 12 exposes the surface of the photoreceptor 10 to form an electrostatic latent image. Next, the developing device 13 containing a developer containing toner therein develops the electrostatic latent image on the surface of the photoreceptor 10 to form a toner image. The image forming apparatus 100 includes a plurality of photoreceptors 10, a developing device 13, and the like. After forming toner images of different colors, the toner images are transferred onto the rotating intermediate transfer belt 20 in a superimposed manner.

  The toner image transferred to the intermediate transfer belt 20 is secondarily transferred to the paper P transported from the paper tray 60 by the transport means at the secondary transfer portion between the intermediate transfer belt 20 and the secondary transfer roller 30. The The sheet P onto which the toner image has been transferred is further conveyed, heated and pressed by the fixing device 40 to fix the toner image, and is discharged to the paper discharge tray 70.

  After the toner image is transferred to the intermediate transfer belt 20, the toner remaining on the surface is removed by the cleaning device 14 to prepare for the next image formation.

  A portion where an image is formed on the sheet P by the developing unit, the intermediate transfer belt 20, the secondary transfer roller 30, the fixing device 40, and the like is hereinafter referred to as an image forming unit.

  The image forming apparatus 100 has a configuration as described above, detects the thickness of the paper P on which an image is to be formed, and optimizes the image forming conditions according to the detected thickness of the paper P. Reduce quality fluctuations.

<Hardware configuration of image forming apparatus>
FIG. 2 is a diagram illustrating a hardware configuration of the image forming apparatus 100 according to the embodiment.

  As shown in FIG. 2, the image forming apparatus 100 includes a CPU 101, a ROM 102, a RAM 103, an HDD 104, a controller 105, a communication I / F 106, a detection IO unit 107, and a recording medium I / F 109, which are connected by a bus.

  The CPU 101 is an arithmetic device that implements each function of the image forming apparatus 100 by reading a program or data from a storage device such as the HDD 104 or the ROM 102 onto the RAM 103 and executing processing.

  The ROM 102 is a nonvolatile semiconductor memory (storage device) that can retain programs and data even when the power is turned off. The ROM 102 stores various programs and data that are executed when the image forming apparatus 100 is activated. The RAM 103 is a volatile semiconductor memory (storage device) that temporarily stores programs and data.

  The HDD 104 is a non-volatile storage device that stores programs and data. The stored programs and data include programs for controlling the entire image forming apparatus 100 and data such as image forming conditions.

  The controller 105 is connected to an image forming unit of the image forming apparatus 100, a transport unit that transports the paper P, and the like, and performs these controls.

  The communication I / F unit 106 has a communication function connected via a network such as a LAN (Local Area Network) or a WAN (Wide Area Network) constructed by a data transmission path such as a wired and / or wireless line. This is an interface between the device and the image forming apparatus 100.

  The detection IO unit 107 is an interface with the detection sensor 108 and acquires a value output from the detection sensor 108. The detection sensor 108 detects the position of the transport unit used to detect the thickness of the paper P on which an image is printed. The configuration of the detection sensor 108 will be described later.

  The recording medium I / F unit 109 is an interface with the recording medium. The image forming apparatus 100 can read and / or write the recording medium 110 via the recording medium I / F 109. The recording medium 110 includes a flexible disk, a CD, a DVD (Digital Versatile Disk), an SD memory card, a USB memory (Universal Serial Bus memory), and the like.

<Functional configuration for detecting paper thickness>
FIG. 3 is a block diagram illustrating a functional configuration for detecting the sheet thickness in the image forming apparatus 100 according to the embodiment.

  As illustrated in FIG. 3, the image forming apparatus 100 includes a controller 105, a detection sensor 108, a conveyance unit 120, a thickness detection unit 121, an adjustment operation detection unit 122, and a storage unit 123.

  As shown in FIG. 4, the conveyance unit 120 includes a driving roller 120a that rotates and a driven roller 120b that rotates following the driving roller 120a. The driven roller 120b is provided so as to be movable toward and away from the driving roller 120a, and is pressed against the driving roller 120a by a pressing means (not shown). The conveyance unit 120 is provided in the image forming apparatus 100 as, for example, roller pairs 31, 32, 33, and 34 that extract and convey the paper P shown in FIG.

  The detection sensor 108 is an example of a position detection unit. The wheel 108a has slits formed at regular intervals, the sensor 108b detects the rotation angle of the wheel 108a by detecting the slit of the wheel 108a, and the rotation of the wheel 108a. The arm 108c is provided so that one end is fixed to the shaft and the other end is in contact with the rotation shaft of the driven roller 120b.

  When the paper P is transported between the drive roller 120a and the driven roller 120b of the transport unit, the driven roller 120b moves away from the drive roller 120a and pushes up the arm 108c of the detection sensor 108 in the direction of the arrow. The wheel 108a is rotated (FIG. 4B). The detection sensor 108 detects the rotational position of the wheel 108a that rotates in accordance with the positional fluctuation of the driven roller 120b due to the conveyance of the paper P in this way, and detects the rotational direction of the driven roller 120b with respect to the driving roller 120a. A value indicating the position is output. As shown in FIG. 5, the detection sensor 108 outputs different values when the paper P is not transported and when it is transported in the transport unit 120.

  As the detection sensor 108, for example, an optical sensor or the like may be used, and the configuration according to the present embodiment is not limited as long as the position of the driven roller 120b can be detected.

  The thickness detection unit 121 acquires a value output from the detection sensor 108 when the paper P is not transported as a reference value, and based on the difference between the value output from the detection sensor 108 when the paper P is transported and the reference value. The thickness of the paper P is detected.

  Here, a fluctuation component corresponding to the rotation period of the driven roller 120b is superimposed on the output of the detection sensor 108 due to the influence of the eccentricity of the driven roller 120b. Therefore, in order to improve the thickness detection accuracy of the paper P, the thickness detection unit 121 outputs the output of the detection sensor 108 while the driven roller 120b rotates for a predetermined time (for example, a time during which the driven roller 120b makes one rotation or more). It is preferable to sample the output of the detection sensor 108 and use the averaged value for detecting the thickness of the paper P.

  FIG. 6 is an output example of the detection sensor 108 averaged by the thickness detection unit 121. As shown in FIG. 6, since the fluctuation component due to the eccentricity of the driven roller 120b can be reduced, the thickness of the paper P can be detected with high accuracy.

  The adjustment operation detection unit 122 in the functional configuration illustrated in FIG. 3 detects from the controller 105 that adjustment operations such as image density and image position deviation are performed in the image forming unit. The thickness detection unit 121 acquires a reference value used for thickness detection of the paper P during the execution of the adjustment operation of the image forming unit detected by the adjustment operation detection unit 122. The adjustment operation of the image forming unit is an operation performed, for example, to stabilize the image density and suppress the fluctuation of the image quality. Based on the toner image formation result of a predetermined pattern, the toner density and development of the developing device 13 are performed. For example, setting of a bias, a charging potential of the photosensitive member 10 by the charging device 11, and a transfer condition from the photosensitive member 10 to the intermediate transfer belt 20 are performed. In addition, for example, when an image is output by superimposing different color toner images, the exposure condition by the exposure device 12 and the driving condition of the photosensitive member 10 are optimized in order to correct the color misregistration. . In addition to the above-described operation, the adjustment operation refers to all the controls performed for image formation on the paper P performed by the image forming unit of the image forming apparatus 100. Such an adjustment operation in the image forming unit is assumed to have a certain time elapsed from the previous image formation, such as when the main power of the image forming apparatus 100 is turned on, when returning from the energy saving mode, when returning from a paper jam, or the like. Done in case.

  The storage unit 123 stores a reference value used for detecting the thickness of the paper P acquired by the thickness detection unit 121 during the adjustment operation of the image forming unit. When detecting the thickness of the paper P, the thickness detection unit 121 acquires the reference value from the storage unit 123 and detects the thickness of the paper P based on the difference from the value output from the detection sensor 108. .

<About paper thickness detection>
The image forming apparatus 100 according to the present embodiment detects the thickness of the paper P at the time of image formation, adjusts the image forming conditions, and applies the paper P under the image forming conditions optimized according to the thickness of the paper P. Form an image.

  FIG. 7 is a diagram illustrating a flowchart of a sheet thickness detection process at the time of image formation of the image forming apparatus 100 according to the present embodiment.

  When the image forming apparatus 100 is instructed to form an image, first, in step S1, the thickness detection unit 121 acquires a reference value necessary for detecting the thickness of the paper P from the storage unit 123. The reference value is a value that is acquired in advance by the thickness detection unit 121 when the paper P is not conveyed in the conveyance unit 120 and is stored in the storage unit 123.

  Next, in step S2, the transport unit 120 is driven to start transporting the paper P, and the detection sensor 108 starts output. Thereafter, in step S3, the thickness detection unit 121 determines the thickness of the sheet P from the difference between the output value from the detection sensor 108 when the sheet P passes through the transport unit 120 and the reference value acquired in step S1. Is detected.

  When the thickness of the paper P is detected by the thickness detection unit 121, the thickness detection unit 121 transmits the thickness detection result of the paper P to the controller 105 in step S4, and the controller 105 in the image forming unit. Set image forming conditions.

  Next, in step S5, an image is printed on the paper P based on the image forming conditions set in the image forming unit, and discharged outside the apparatus.

  As described above, the image forming apparatus 100 outputs an optimum image according to the thickness of the paper P by adjusting the image forming conditions based on the thickness of the paper P detected by the thickness detection unit 121. It is possible.

  Next, a process in which the thickness detection unit 121 acquires a reference value for detecting the thickness of the paper P will be described.

  The reference value is acquired by the thickness detection unit 121 during the adjustment operation in the image forming unit that is performed when the power to the image forming apparatus 100 is turned on, when returning from the energy saving mode, when returning from a paper jam, or the like. . By acquiring the reference value during the adjustment operation in the image forming unit, it is not necessary to acquire the reference value every time printing is performed on the paper P. Therefore, the time required for image formation can be shortened. become.

  FIG. 8 is a diagram illustrating a flowchart of a process in which the thickness detection unit 121 acquires a reference value used for thickness detection of the paper P.

  As shown in FIG. 8, first, in step S <b> 11, the adjustment operation detection unit 122 detects from the controller 105 whether or not the adjustment operation is being executed in the image forming unit. As described above, the adjustment operation of the image forming unit is, for example, setting of development conditions necessary for correction of image density and color misregistration, and the like from the energy saving mode when the main power of the image forming apparatus 100 is turned on. This is performed when returning from a paper jam or when returning from a paper jam.

  When the adjustment operation detection unit 122 detects that the adjustment operation in the image forming unit has started in step S11, the thickness detection unit 121 identifies the cause of the start of the adjustment operation in step S12. When the detected adjustment operation is executed by turning on the power to the image forming apparatus 100 or returning from the energy saving mode, in step S13, the thickness detection unit 121 performs a reference value acquisition process.

  If the adjustment operation detected in step S14 is executed when the image forming apparatus 100 is recovered from the paper jam, whether or not the door of the image forming apparatus 100 is opened or closed in step S15. Is detected. If opening / closing of the door is detected, the thickness detection unit 121 performs reference value acquisition processing in step S13. Note that the door opening / closing detection in step S15 is preferably performed on the door close to the conveyance unit 120 that detects the thickness of the paper P, the detection sensor 108, and the like. Since the removal of the paper P is performed in the vicinity of the transport unit 120 or the like that detects the thickness of the paper P, the reference value may vary due to user contact with the transport unit 120, vibration, or the like. It is. Further, when opening / closing of a door away from the transport unit 120 or the like is detected, the reference value is unlikely to fluctuate, so the reference value acquisition process may not be performed.

  FIG. 9 is a diagram illustrating a flowchart of reference value acquisition processing by the thickness detection unit 121 in the present embodiment.

  In the reference value acquisition process by the thickness detection unit 121, first, in step S131, driving of the conveyance unit 120 and output of the detection sensor 108 are started. Next, in step S132, the thickness detection unit 121 acquires the output value from the detection sensor 108 for 1 sec, for example.

  In step S133, the difference between the maximum value and the minimum value of the output value of the detection sensor 108 acquired by the thickness detection unit 121 is within a predetermined range (for example, within 5 μm in terms of the thickness of the paper P). Judge whether there is.

  If the difference between the maximum value and the minimum value of the output value of the detection sensor 108 is within a predetermined range, the average value of the output values from the detection sensor 108 acquired by the thickness detection unit 121 is obtained in step S134. calculate.

  Next, in step S135, the reference value previously acquired by the thickness detection unit 121 is acquired from the storage unit 123, and in step S136, the average value calculated in step S134 is compared with the previously acquired reference value. To do.

  If the difference between the calculated average value and the previously acquired reference value is within a predetermined range (for example, within 5 μm in terms of the thickness of the paper P), the calculated average value is determined in step S137. It acquires as a reference value, preserve | saves in the memory | storage part 123, and complete | finishes a reference value acquisition process.

  When the difference between the maximum value and the minimum value of the output value of the detection sensor 108 acquired by the thickness detection unit 121 is not within the predetermined range (S133: No), or the average value calculated by the thickness detection unit 121 and the previous acquisition If the difference from the determined reference value is not within the predetermined range (S136: No), the process proceeds to step S138.

  In step S138, it is determined whether or not the number of acquisitions of the output value from the detection sensor 108 by the thickness detection unit 121 is, for example, less than 3, and if it is less than 3, the image formation is performed in step S139. It is determined whether it is within the adjustment operation time of the unit.

  When the number of times the thickness detection unit 121 obtains the output value from the detection sensor 108 is less than 3 (S138: Yes) and within the adjustment operation time of the image forming unit (S139: Yes), step S132 is performed. Then, the thickness detection unit 121 obtains the output value from the detection sensor 108 again, and performs the processing after step S133.

  When the thickness detection unit 121 obtains the output value from the detection sensor 108 three times or more (S138: No), or when the adjustment operation of the image forming unit has already been completed (S139: No), step S140 is performed. Then, it is determined that an abnormality has occurred in the transport unit 120 or the detection sensor 108, an error is output, and the process is terminated. Note that the error detected by the pressure production detection unit 121 may be displayed on a display unit included in the image forming apparatus 100.

  As described above, in the image forming apparatus 100 according to the present embodiment, the thickness detection unit 121 acquires a reference value necessary for detecting the thickness of the paper P during the adjustment operation in the image forming unit. . Therefore, since the reference value acquisition time at the time of image formation of the image forming apparatus 100 is omitted, the thickness of the paper P can be increased without extending the time from the start of the image forming operation to the printing and output of the image. It is possible to detect this.

  Up to this point, the present invention has been described based on the above-described embodiment, but the function of the image forming apparatus 100 according to the above-described embodiment is the same as the processing procedure described above for the image forming according to the above-described embodiment. It can be realized by executing as a program coded in a programming language suitable for the apparatus 100. Therefore, a program for realizing each function of the image forming apparatus 100 according to the embodiment can be stored in the computer-readable recording medium 113.

  Therefore, the program according to the above embodiment can be installed in the image forming apparatus 100 from the recording medium 113 by being stored in the recording medium 113 such as a flexible disk, a CD, a DVD, or a USB memory. Since the image forming apparatus 100 includes the communication I / F unit 105, the program according to the above embodiment can be downloaded and installed via an electric communication line such as the Internet.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations shown here, such as combinations with other elements, etc., in the configurations described in the above embodiments. These points can be changed without departing from the spirit of the present invention, and can be appropriately determined according to the application form.

100 Image forming apparatus 108 Detection sensor (position detection means)
120 Conveying section (conveying means)
120a Drive roller 120b Follower roller 121 Thickness detector (thickness detector)
122 Adjustment operation detection unit (adjustment operation detection means)
123 Storage unit (storage means)
P paper (recording medium)

JP 2009-249074 A

Claims (7)

A conveying means for nipping and conveying the recording medium between the driving roller and a driven roller that is pressed by the driving roller and rotated.
Position detecting means for outputting a value indicating the position of the driven roller in the contact / separation direction with respect to the driving roller;
A value output from the position detection unit when the recording medium is not conveyed is obtained as a reference value, and based on a difference between the value output from the position detection unit and the reference value when the recording medium is conveyed, A thickness detecting means for detecting the thickness of the recording medium;
Adjustment operation detecting means for detecting that an adjustment operation is being performed in the image forming unit that forms an image on the recording medium,
The image forming apparatus according to claim 1, wherein the thickness detection unit acquires the reference value when the adjustment operation detection unit detects that the adjustment operation of the image forming unit is performed. The image forming apparatus according to claim 1, wherein the thickness detection unit acquires an average value of values output by the position detection unit while the driven roller rotates for a predetermined time as the reference value. . The thickness detecting unit obtains the reference value again when the maximum value and the minimum value output by the position detecting unit are not within a predetermined range while the driven roller rotates for a predetermined time. The image forming apparatus according to claim 1, wherein: Storage means for storing the reference value acquired by the thickness detection means;
The thickness detecting unit acquires the reference value again when a difference between the acquired reference value and the previously acquired reference value stored in the storage unit is a predetermined value or more. The image forming apparatus according to any one of claims 1 to 3. The thickness detection unit is configured to execute the adjustment operation of the image forming unit performed at any one of power-on of the image forming apparatus, return from the energy saving mode, and return from paper jam. The image forming apparatus according to claim 1, wherein the reference value is acquired. A conveying means for nipping and conveying the recording medium between the driving roller and a driven roller that is pressed by the driving roller and rotated.
A position detection unit that outputs a value indicating a position of the driven roller in the contact / separation direction with respect to the driving roller, and a thickness detection method for a recording medium in an image forming apparatus,
A value output from the position detection unit when the recording medium is not conveyed is obtained as a reference value, and based on a difference between the value output from the position detection unit and the reference value when the recording medium is conveyed, A thickness detecting step for detecting the thickness of the recording medium;
An adjustment operation detecting step of detecting that an adjustment operation is being performed in the image forming unit that forms an image on the recording medium,
The thickness detection step acquires the reference value when it is detected that the adjustment operation of the image forming unit is performed by the adjustment operation detection step. .   A program for causing a computer to execute the recording medium thickness detection method according to claim 6.

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