JP2009109335A - Recording material discriminating device and image forming apparatus equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording material discriminating device capable of preventing the attachment of foreign bodies to a detection window and an imaging lens, and an image forming device equipped with the same. <P>SOLUTION: The problem is solved by the recording material discriminating device including: a light irradiating means 42 for irradiating a recording material with light; an image forming means 44 for forming an image from a reflected light which is irradiated from the light irradiating means and reflected from the recording material; an imaging means 43 for outputting the reflected light image formed by the image forming means by converting to an electric signal; an ultrasonicc wave irradiation means 451 for irradiating the recording material with ultrasonic waves; an ultrasonic wave receiving means 461 for outputting the ultrasonic wave which is irradiated from an ultrasonic wave irradiating means and pass through the recording material by converting to an electric signal; a transparent plate member 41 covering the front of the image forming means and ultrasonic wave irradiating means or ultrasonic receiving means and attached to a vibrating part of the ultrasonic wave irradiating means; and a type discriminating means 10 for discriminating the type of the recording material based on the outputs of the imaging means and the ultrasonic wave receiving means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes a recording material discriminating apparatus that detects the surface property by imaging the surface of the recording material, and further detects the thickness by ultrasonic waves transmitted through the recording material, and discriminates the type of the recording material. The present invention relates to an image forming apparatus. In particular, the present invention relates to a technique for preventing the foreign matter from adhering to the detection unit of the recording material discriminating apparatus or removing the attached foreign matter.

  Image forming apparatuses such as copying machines and laser printers include a latent image carrier that carries a latent image, and a developing device that visualizes the latent image as a developer image by applying a developer to the latent image carrier. ing. The image forming apparatus further includes a transfer unit that transfers the developer image by the developing device to a recording material conveyed in a predetermined direction under a predetermined transfer condition. The image forming apparatus further includes a fixing device that fixes the developer image to the recording material by heating and pressurizing the recording material, which has received the developer image transferred by the transfer device, under predetermined fixing conditions.

  Conventionally, in such an image forming apparatus, for example, a user sets the size and type (hereinafter also referred to as a paper type) of a recording sheet as a recording material on an operation panel or the like provided in the main body of the image forming apparatus. The transfer conditions (for example, transfer bias and recording paper transport speed during transfer) and fixing conditions (for example, the fixing temperature and recording paper transport speed during fixing) are controlled in accordance with the setting. .

In recent years, a method has been proposed in which the type of recording material is discriminated using a sensor for discriminating the recording material inside the image forming apparatus, and control is performed so that transfer conditions or fixing conditions are set according to the discrimination results. .
Specifically, as proposed in Patent Document 1, the surface smoothness is detected by imaging the surface of the recording material with a CMOS sensor to determine the type of the recording material. Alternatively, as proposed in Patent Document 2, a light source is provided at a position facing a sensor for determining a recording material, and the thickness is determined by detecting transmitted light that has passed through the recording material. Further, as proposed in Patent Document 3, there is an example in which the surface property and thickness are discriminated by irradiating the recording material with ultrasonic waves and detecting the reflectance and transmittance from the recording material.
JP 2002-182518 A JP 2001-139189 A Japanese Patent Laid-Open No. 2004-219856

According to the study by the inventors of the present invention, the transmitted light method is affected not only by the thickness of the recording material but also by the whiteness in detecting the thickness of the recording material. Has better discrimination ability.
On the other hand, the method of detecting the surface smoothness by imaging the surface of the recording material with an image sensor such as a CMOS sensor and discriminating the type of the recording material is more than the method of detecting and discriminating the reflectance of ultrasonic waves. High discrimination ability for surface smoothness.
That is, a combination of detecting the thickness by the ultrasonic method and detecting the surface smoothness by the imaging method is preferable. However, the imaging method has a weak point in that when the light receiving window of the image sensor is soiled with paper dust or the like, the original surface image of the recording material cannot be obtained, and as a result, the type of the recording material is erroneously determined.

  As a technique for solving such a problem, there is a technique for preventing entry of foreign matter by providing a shutter mechanism as proposed in Japanese Patent Laid-Open No. 2005-202260. Further, as proposed in Japanese Patent Application Laid-Open No. 2004-085787, there is a method for preventing the adhesion of foreign matter to the detection window by providing an air path in the vicinity of the detection window of the recording material discriminating apparatus. However, the method of providing the shutter mechanism has a complicated structure and is expensive, and the method of providing one air path sometimes increases the adhesion of foreign matter.

  The present invention has been made under such circumstances. The surface smoothness is detected by imaging the surface of the recording material, and the recording material is irradiated with ultrasonic waves to determine the basis weight or The present invention relates to an improvement of a recording material discriminating apparatus that discriminates the type of recording material by detecting the thickness. That is, a recording material discriminating apparatus capable of preventing the foreign matter from adhering to the imaging lens for forming the surface image of the recording material on the detection window or the image sensor, or removing the adhered foreign matter, and It is an object of the present invention to provide an image forming apparatus used.

  In order to solve the above problems, in the present invention, the recording material discriminating apparatus is configured as described in the following (1) to (3), and the image forming apparatus is configured as described in the following (4).

(1) Light irradiating means for irradiating the recording material with light, imaging means for forming an image of reflected light irradiated by the light irradiating means and reflected from the recording material, and reflection imaged by the imaging means An imaging unit that converts a light image into an electrical signal and outputs it, an ultrasonic irradiation unit that irradiates the recording material with ultrasonic waves, and an ultrasonic wave that is irradiated by the ultrasonic irradiation unit and transmitted through the recording material Ultrasonic wave receiving means that converts and outputs an electrical signal; a translucent plate-like member that covers the imaging means and the front face of the ultrasonic wave irradiation means; and is coupled to the vibrating portion of the ultrasonic wave irradiation means; A type discriminating unit for discriminating the type of the recording material based on the output of the imaging unit and the output of the ultrasonic wave receiving unit;
Recording material discrimination device.

(2) a light irradiating means for irradiating the recording material with light, an imaging means for forming an image of reflected light irradiated by the light irradiating means and reflected from the recording material, and a reflection imaged by the imaging means An imaging unit that converts a light image into an electrical signal and outputs it, an ultrasonic irradiation unit that irradiates the recording material with ultrasonic waves, and an ultrasonic wave that is irradiated by the ultrasonic irradiation unit and transmitted through the recording material An ultrasonic receiving means for converting the electric signal into an output; a type determining means for determining the type of the recording material based on the output of the imaging means and the output of the ultrasonic receiving means;
The image forming means is a recording material discriminating device which is a plate-like member which is coupled to the vibration part of the ultrasonic wave irradiation means or the ultrasonic wave reception means and covers the front surface of the ultrasonic wave irradiation means or the ultrasonic wave reception means .

(3) Light irradiating means for irradiating the recording material with light, imaging means for forming an image of reflected light irradiated by the light irradiating means and reflected from the recording material, and reflection imaged by the imaging means An imaging unit that converts a light image into an electrical signal and outputs it, an ultrasonic irradiation unit that irradiates the recording material with ultrasonic waves, and an ultrasonic wave that is irradiated by the ultrasonic irradiation unit and transmitted through the recording material Ultrasonic wave receiving means that converts and outputs an electrical signal, and a translucent plate-like shape that covers the imaging means and the front face of the ultrasonic wave irradiation means, and is disposed with a gap between the vibration part of the ultrasonic wave irradiation means A type discriminating unit for discriminating the type of the recording material on the basis of a member, an output of the imaging unit and an output of the ultrasonic wave receiving unit;
Recording material discrimination device.

  (4) An image forming apparatus comprising the recording material discrimination device according to any one of (1) to (3), wherein a control parameter related to an image forming operation is changed based on a discrimination result by the recording material discrimination device.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesion of the foreign material to a detection part can be suppressed or the foreign material which adhered can be removed. Thereby, the type of the recording medium can be accurately detected, and the image forming apparatus can be appropriately controlled.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

  FIG. 1 is a cross-sectional view illustrating a configuration of a “color image forming apparatus” according to the first exemplary embodiment. This embodiment is a tandem type color image forming apparatus employing an intermediate transfer belt.

First, the configuration and operation of the image forming unit in the color image forming apparatus of this embodiment will be described with reference to FIG.
The image forming unit includes a paper feed cassette 15, photosensitive members (hereinafter referred to as photosensitive drums) 1Y, 1M, 1C, and 1BK for each station of each color of CMYK, charging rollers 2Y, 2M, 2C, and 2BK as primary charging means, and an exposure light scanner. The units 11Y, 11M, 11C, and 11BK are provided. Further, developing devices 8Y, 8M, 8C, and 8BK as developing means, an intermediate transfer belt 24, a driving roller 23 that drives the intermediate transfer belt 24, and a tension roller 13, primary transfer rollers 4Y, 4M, 4C, 4BK, two A secondary transfer roller 25 and a secondary transfer counter roller 26 are provided. In addition, the image forming apparatus includes a fixing unit 21 and a control unit 10 that controls these.

  The photosensitive drums 1Y, 1M, 1C, and 1BK are configured by applying an organic optical transmission layer to the outer periphery of an aluminum cylinder, and rotate by receiving a driving force of a driving motor (not shown). The drive motor rotates the photosensitive drums 1Y, 1M, 1C, and 1BK in the clockwise direction in accordance with the image forming operation.

  When the control unit 10 receives the image signal, the recording material P is sent out from the paper feed cassette 15 or the like into the color image forming apparatus by the paper feed rollers 17 and 18. Then, it is once sandwiched and stopped by a roller-like synchronous rotating body for synchronizing the image forming operation described later and the conveyance of the recording material P, that is, the conveyance (registration) roller 19a and the conveyance (registration) counter roller 19b. And wait.

On the other hand, in accordance with the received image signal, the control unit 10 detects the photosensitive drums 1Y, 1M, 1M, 11M, 11C, 11BK charged to a constant potential by the action of the charging rollers 2Y, 2M, 2C, 2BK. An electrostatic latent image is formed on the surface of 1C and 1BK.
Developing units 8Y, 8M, 8C, and 8BK are means for visualizing the electrostatic latent image, and develop yellow (Y), magenta (M), cyan (C), and black (BK) for each station. Each developing device is provided with sleeves 5Y, 5M, 5C, and 5BK, and a developing bias for visualizing the electrostatic latent image is applied thereto.

As described above, the electrostatic latent images formed on the surfaces of the photosensitive drums 1Y, 1M, 1C, and 1BK are developed as monochromatic toner images by the action of the developing devices 8Y, 8M, 8C, and 8BK.
Each photosensitive drum 1, charging roller 2, and developing device 8 are integrated, and are attached in the form of a toner cartridge 31 that is detachable from the color image forming apparatus main body.

  The intermediate transfer belt 24 is in contact with the photosensitive drums 1Y, 1M, 1C, and 1BK, and rotates in the counterclockwise direction in synchronism with the rotation of the photosensitive drums 1Y, 1M, 1C, and 1BK during color image formation. The developed single color toner image is sequentially transferred to the intermediate transfer belt 24 by the action of the primary transfer bias applied to the primary transfer roller 4 and becomes a multicolor toner image on the intermediate transfer belt 24.

  Thereafter, the multicolor toner image formed on the intermediate transfer belt 24 is conveyed to a secondary transfer nip portion formed by the secondary transfer counter roller 26 and the secondary transfer roller 25. At the same time, the recording material P that has been waiting while being sandwiched between the pair of conveying rollers 19ab is synchronized with the multicolor toner image on the intermediate transfer belt 24 by the action of the pair of conveying rollers 19ab, and enters the secondary transfer nip portion. Be transported. Then, the multicolor toner image on the intermediate transfer belt 24 is collectively transferred onto the recording material P by the action of the secondary transfer bias applied to the secondary transfer roller 25.

The fixing unit 21 melts and fixes the transferred multi-color toner image on the recording material P while conveying the recording material P. As shown in FIG. 1, the fixing roller 21 a that heats the recording material P and the recording material A pressure roller 21b for pressing P against the fixing roller 21a is provided.
The fixing roller 21a and the pressure roller 21b are formed in a hollow shape, and heaters 21ah and 21bh are incorporated therein, respectively.

The recording material P holding the multicolor toner image is conveyed by the fixing roller 21a and the pressure roller 21b, and heat and pressure are applied to fix the toner on the surface of the recording material P.
The recording material P after the toner image is fixed is discharged to the paper discharge tray 16 by the discharge roller 20, and the image forming operation is completed.
The cleaning means 28 cleans the toner remaining as a transfer residue on the intermediate transfer belt 24, and the transfer residual toner collected here is stored in a cleaner container 29 as waste toner.
Such a series of image forming operations is controlled by the control unit 10 provided in the color image forming apparatus.

In the color image forming apparatus of FIG. 1, a recording material discriminating device 40, which is a main part of the present embodiment, is installed so that a recording material conveyance path is sandwiched between recording material discrimination units in front of the pair of conveyance rollers 19ab. The recording material discriminating device 40 can detect information reflecting the surface smoothness of the recording material P conveyed from the paper feed cassette 15 and the like and information reflecting the basis weight or thickness. The detection by the recording material discriminating device 40 is performed while the recording material P is sent out from the paper feed cassette 15 or the like into the color image forming apparatus and is held between the conveyance (registration) roller pair 19ab and stopped.
The control unit 10 discriminates the type of the recording material based on the detection information sent from the recording material discriminating device 40, and controls the color image forming apparatus by setting the optimum transfer bias and fixing temperature for that type. Let

Next, the recording material discrimination device 40 will be described. FIG. 2 is a schematic cross-sectional view showing a schematic configuration for detecting information reflecting surface smoothness and information reflecting basis weight or thickness. The recording material discriminating apparatus 40 drives the two detection units, a surface detection unit 40a that detects information reflecting surface smoothness, a basis weight detection unit 40b that detects information reflecting basis weight or thickness, and the like. It comprises a drive / calculation unit 40c that computes the output signal from the detection unit. In addition, a transparent detection window member 41 (corresponding to the translucent plate-like member in the claims) is provided so as to cover the front surfaces of the two detection units and prevent paper dust and dust from entering the two detection units. is doing.
As shown in FIG. 2, the surface detection unit 40a includes a reflective LED 42 that is a light irradiation unit, a CMOS area sensor 43 that is an imaging unit, and an imaging lens 44 that is an imaging unit.
The light having the reflection LED 42 as a light source is irradiated toward the surface of the recording material P. The reflecting LED 42 is arranged to irradiate light obliquely at a predetermined angle. In this embodiment, the reflecting LED 42 is arranged so that the angle formed by the surface of the recording material and the LED light irradiation direction is 30 °. By irradiating light obliquely, the reflected light from the recording material P includes shadow information reflecting the surface smoothness of the recording material P (corresponding to the reflected light image in the claims). The reflected light is transmitted through the detection window member 41, and then condensed through the imaging lens 44 to form an image on the CMOS area sensor 43. The CMOS area sensor 43 changes in accordance with the amount of reflected light for each imaged area. A video voltage signal (corresponding to the electrical signal in the claims) is output. Upon receiving the video voltage output signal output from the CMOS area sensor 43, the driving / calculating unit 40c performs A / D conversion on this and outputs the converted digital signal to the control unit 10.
The controller 10 identifies the surface state of the recording material P by analyzing the received digital signal as an image.

On the other hand, the basis weight detector 40b includes an ultrasonic transmitter 451 and an ultrasonic receiver 461, as shown in FIG.
The ultrasonic transmitter 451 is arranged side by side with the surface detection unit 40a, and when the drive pulse signal is input from the drive / calculation unit 40c, the ultrasonic transmitter 451 transmits an ultrasonic signal toward the recording material P. Equivalent to ultrasonic irradiation). The ultrasonic transmitter 451 used in this embodiment has a configuration using a bimorph vibrator 451a (corresponding to a vibrating portion in claims) shown in FIG. The ultrasonic wave transmitting surface of the bimorph vibrator 451a is bonded to the detection window member 41 with an epoxy-based adhesive, and the ultrasonic wave transmitter 451 and the detection window member 41 are integrated. For this reason, the ultrasonic transmitter 451 directly vibrates the detection window member 41 with ultrasonic waves.

  In the present embodiment, the drive pulse signal from the drive / calculation unit 40c is a rectangular wave having a frequency of 40 KHz and a PP voltage of 12 V, whereby the ultrasonic transmitter 451 gives an ultrasonic vibration of 40 KHz to the detection window member 41. The ultrasonic waves generated thereby are irradiated toward the recording material P. The ultrasonic receiver 461 is installed so as to face the ultrasonic transmitter 451 across the conveyance path of the recording material P, and receives the ultrasonic wave transmitted through the recording material P. The ultrasonic receiver 461 has a structure in which a cone-shaped diaphragm 461b is attached to a bimorph vibrator 461a as shown in FIG. 4 for the purpose of increasing the reception sensitivity, and it corresponds to the received intensity of the received ultrasonic wave. Outputs a changing voltage signal. Since the intensity of the ultrasonic wave transmitted through the recording material P is attenuated according to the basis weight or thickness of the recording material P, the voltage signal output from the ultrasonic receiver 461 is information reflecting the basis weight or thickness. It will be included.

Upon receiving the voltage output signal output from the ultrasonic receiver 461, the driving / calculating unit 40c performs A / D conversion on the voltage output signal, and outputs the converted digital signal to the control unit 10.
The controller 10 identifies the basis weight or thickness of the recording material P by analyzing the received digital signal.

  As described above, the control unit 10 identifies the surface state and basis weight or thickness of the recording material P based on the information sent from the recording material determination device 40 and determines the type of the recording material (of the claims). Equivalent to type discrimination). Then, the optimum secondary transfer bias and fixing temperature are calculated from the respective identification results, and the color image forming apparatus is controlled to operate with the calculated settings (corresponding to changing the parameters in the claims).

  Incidentally, the ultrasonic transmitter 451 provided in the recording material discriminating apparatus 40 has a function of transmitting the ultrasonic wave toward the recording material P to obtain the basis weight or thickness information of the recording material P as described above. In addition, the detection window member 41 is vibrated to remove paper dust and dust attached thereto.

  As described above, when ultrasonic waves are transmitted from the ultrasonic transmitter 451 toward the recording material P when obtaining the basis weight or thickness information of the recording material P, the recording material P is integrated with the ultrasonic transmitter 451. The detection window member 41 also vibrates ultrasonically. At this time, as shown in FIG. 3, paper dust and dust (D in the figure) adhering to the detection window member 41 are also ultrasonically vibrated together with the detection window member 41, so that kinetic energy Ek is obtained. As a result, if the kinetic energy is larger than the adhesion energy Ea to the detection window member 41, the paper dust / dust is detached from the detection window member 41.

  In this embodiment, 2000 A4-size plain papers were passed using the above-described color image forming apparatus, and the recording material P was discriminated by the recording material discriminating apparatus 40 every time one sheet was passed. Table 1 shows the error rates of the visual confirmation result of the degree of adhesion of paper dust and dust to the detection window member 41 after passing 2,000 sheets, and the discrimination result of the surface condition of the recording material by the recording material discrimination device. Thus, an apparent improvement effect was confirmed as compared with the case where 2000 sheets were passed while the surface state identification was performed by operating only the surface detection unit 40a without operating the basis weight determination unit 40b.

  In this embodiment, the ultrasonic transmitter 451 in the basis weight detection unit 40b is configured to transmit ultrasonic vibrations of 40 KHz, but there is no restriction on the frequency band, and the basis weight or thickness of the recording material P is reflected. It is possible to use ultrasonic waves of any frequency from which information can be obtained. However, if the frequency is too high, attenuation of the sound pressure in the air or in the recording material increases, and this hinders discrimination of the recording material. Therefore, an ultrasonic wave of about 20 KHz to 300 KHz is preferably used as a specific frequency band. .

  As described above, according to the present embodiment, it is possible to suppress the adhesion of foreign matter to the imaging lens or the detection window member or to remove the foreign matter attached thereto, thereby reducing the number of cases where the type of recording material is erroneously determined.

  A “color image forming apparatus” that is Embodiment 2 will be described. Since the configuration of the color image forming apparatus is the same as that of the first embodiment except for the recording material discriminating apparatus 40, the description of the first embodiment is cited and the description of the entire color image forming apparatus is omitted here.

  As shown in FIGS. 5 and 6, the recording material discriminating apparatus 40 includes a surface detection unit 40a, a basis weight detection unit 40b, and a drive / calculation unit 40c, as shown in FIGS. An imaging lens member 442 is provided as an imaging means without providing a window member. The imaging lens member 442 has an imaging lens portion 442a and a joint portion 442b (corresponding to the other area of the claims), and is bonded to the bimorph vibrator 462a of the ultrasonic receiver 462 at the joint portion 442b. ing.

  In this embodiment, the bimorph transducer 462a constituting the ultrasonic receiver 462 outputs a voltage signal that changes according to the received intensity of the received ultrasonic wave, and when it receives a drive pulse signal, it vibrates ultrasonically accordingly. It is possible.

  The ultrasonic transmitter 452 has a structure in which a cone-shaped diaphragm 452b is attached to a bimorph vibrator 452a as shown in FIG. In this embodiment, when the recording material is discriminated, a driving pulse signal having a rectangular wave of 200 KHz and PP voltage of 12 V is given to the ultrasonic transmitter 452 from the driving / calculating unit 40c. Accordingly, the recording material P is irradiated with an ultrasonic wave of 200 KHz, and the ultrasonic wave transmitted through the recording material P is received by the ultrasonic receiver 462. While the color image forming apparatus is performing an operation other than the recording material determination, the ultrasonic wave receiver 462 is supplied with a rectangular pulse driving pulse signal of 200 KHz and a PP voltage of 12 V from the driving / calculating unit 40c. As a result, the ultrasonic receiver 462 ultrasonically vibrates at 200 KHz, whereby vibration is applied to the imaging lens member 442.

  Also in the present embodiment, as in the first embodiment, 2000 sheets of A4 size plain paper are passed, and the recording material P discriminating operation is performed by the recording material discriminating apparatus 40 every time one sheet is passed. While the color image forming apparatus is performing an operation other than the discrimination operation, the ultrasonic receiver 462 is ultrasonically vibrated at 200 KHz to prevent paper dust and dust from adhering to the coupling lens member 442. Table 2 shows the error rates of the visual confirmation result of the adhesion degree of the paper dust and the dust to the coupling lens member 442 after passing 2000 sheets and the identification result of the surface state. Thus, an apparent improvement effect was confirmed as compared with the case where 2000 sheets were passed while the surface state identification was performed by operating only the surface detection unit 40a without operating the basis weight determination unit 40b.

  In the present embodiment, the ultrasonic transmitter 452 in the basis weight detection unit 40b is configured to transmit 200 KHz ultrasonic vibration, but there is no restriction on the frequency band. However, it is preferable to use an ultrasonic wave of about 20 KHz to 300 KHz for the same reason as described in the first embodiment.

  As described above, according to the present embodiment, the adhesion of foreign matter to the imaging lens can be suppressed or the foreign matter attached thereto can be removed, and the number of cases in which the type of recording material is erroneously determined is reduced.

  A “color image forming apparatus” that is Embodiment 3 will be described. Since the configuration of this embodiment is the same as that of the first embodiment except for the recording material discriminating device 40, the description of the first embodiment is used and the description of the entire color image forming apparatus is omitted.

  As in the first embodiment, the recording material discriminating device 40 includes a surface detection unit 40a, a basis weight detection unit 40b, and a drive / calculation unit 40c, and includes a detection window member 41 that prevents paper dust and dust from entering the detection unit. is doing. However, as shown in FIG. 8, the detection window member 41 and the ultrasonic transmitter 453 have separate structures. That is, the detection window member 41 is arranged with a gap from the ultrasonic transmitter 453. A cone-shaped diaphragm 45b for improving directivity and acoustic efficiency is attached to the surface of the bimorph vibrator 453a constituting the ultrasonic transmitter 453.

  In this embodiment, the drive pulse signal (corresponding to the drive voltage for the discrimination operation in claims) given from the drive / calculation unit 40c when performing the discrimination operation of the recording material P has a frequency of 40 kHz and a PP voltage of 24V. It is a square wave. As a result, the ultrasonic transmitter 453 gives a 40 KHz ultrasonic wave to the detection window member 41. At this time, the surface of the detection window member 41 facing the ultrasonic transmitter 453 receives the ultrasonic signal from the ultrasonic transmitter 453 and the detection window member 41 vibrates, and this vibration is the opposite surface side of the detection window member 41. Vibrate the air. Thereby, the ultrasonic signal is irradiated toward the recording material P, and the ultrasonic wave transmitted through the recording material P is received by the ultrasonic receiver having the same configuration as in the first embodiment.

  Further, in the third embodiment, in addition to the above-described determination operation, a driving voltage having a plurality of frequencies and amplitudes as shown in FIG. The ultrasonic transmitter 453 is driven in the cleaning drive mode in combination with the voltage. Here, the cleaning drive mode is a mode in which the recording material discriminating apparatus 40 is driven with a drive voltage that combines a plurality of frequencies and amplitude voltages suitable for removing paper dust and dust attached to the detection window member 41. .

  Also in this embodiment, as in the first embodiment, the recording material P is discriminated by the recording material discrimination device 40 every time one sheet is passed. Then, every time the color image forming apparatus passes 100 sheets, the image forming operation is interrupted and a cleaning operation is performed in which the ultrasonic transmitter 453 is driven in the cleaning drive mode described above. When such an operation is repeated, the error rate of the visual confirmation result of the adhesion degree of the paper dust / dust to the detection window member 41 after passing 2000 sheets and the identification result of the surface state are as shown in Table 3. Thus, an apparent improvement effect was confirmed as compared with the case where 2000 sheets were passed while the surface state identification was performed by operating only the surface detection unit 40a without operating the basis weight determination unit 40b.

  As described above, according to the present embodiment, it is possible to suppress the adhesion of foreign matter to the imaging lens or the detection window member or to remove the foreign matter attached thereto, thereby reducing the number of cases where the type of recording material is erroneously determined.

(Modification of Example)
In the first to third embodiments, the light source in the surface detection unit 40a is an LED. However, for example, a xenon tube, a halogen lamp, or the like can be used. Further, a CCD type sensor may be used as the reading means instead of the CMOS type sensor.
Further, it is described that the result identified by the control unit 10 based on the detection result by the recording material discriminating apparatus 40 is fed back to the control of the transfer bias / fixing temperature. However, it is also possible to feed back to various control parameters and a series of image formation speeds (process speeds) in each process of latent image formation and development, for example.

Further, in the second embodiment, the ultrasonic receiver is driven as an ultrasonic transmitter and the foreign matter is removed during a period other than the determination operation period, but the same configuration is applied to the first and third embodiments. Can do.
In the third embodiment, the ultrasonic transmitter is driven by a driving voltage that is a combination of a driving voltage having a plurality of frequencies and amplitudes, which is different from the driving voltage at the time of the discriminating operation. It can be.

Sectional drawing which shows the structure of the color image forming apparatus of Example 1. FIG. Sectional drawing which shows the structure of the recording material discrimination apparatus in Example 1 Sectional drawing which shows the coupling | bonding relationship of the bimorph vibrator | oscillator and detection window member of an ultrasonic transmitter Sectional drawing which shows the structure of an ultrasonic receiver Sectional drawing which shows the structure of the recording material discrimination | determination apparatus in Example 2. Sectional drawing which shows the coupling | bonding relationship of the bimorph vibrator | oscillator and imaging lens member of an ultrasonic receiver Cross-sectional view showing the configuration of an ultrasonic transmitter Sectional drawing which shows the positional relationship of the bimorph vibrator | oscillator and detection window member of the ultrasonic transmitter in Example 3. The figure which shows the drive waveform in the drive mode for cleaning

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Control part 40 Recording material discrimination apparatus 41 Detection window member 42 LED for reflection
43 CMOS area sensor 44 Imaging lens 451, 452, 453 Ultrasonic transmitter 461, 462 Ultrasonic receiver

Claims (6)

A light irradiating means for irradiating the recording material with light; an image forming means for forming an image of reflected light irradiated from the light irradiating means and reflected from the recording material; and a reflected light image formed by the image forming means. Imaging means for converting to electrical signals and outputting; ultrasonic irradiation means for irradiating the recording material with ultrasonic waves; and receiving ultrasonic waves irradiated by the ultrasonic irradiation means and transmitted through the recording material to generate electrical signals. Ultrasonic wave receiving means for converting and outputting, and translucency covering the front face of the imaging means and the ultrasonic wave irradiating means or the ultrasonic wave receiving means and coupled to the vibrating part of the ultrasonic wave radiating means or the ultrasonic wave receiving means A type discriminating unit for discriminating the type of the recording material based on the output of the imaging unit and the output of the ultrasonic wave receiving unit;
A recording material discriminating apparatus comprising: A light irradiating means for irradiating the recording material with light; an image forming means for forming an image of reflected light irradiated from the light irradiating means and reflected from the recording material; and a reflected light image formed by the image forming means. Imaging means for converting to electrical signals and outputting; ultrasonic irradiation means for irradiating the recording material with ultrasonic waves; and receiving ultrasonic waves irradiated by the ultrasonic irradiation means and transmitted through the recording material to generate electrical signals. An ultrasonic receiving means for converting and outputting; a type determining means for determining the type of the recording material based on the output of the imaging means and the output of the ultrasonic receiving means;
The imaging means is a plate-like member that is coupled to the vibration part of the ultrasonic irradiation means or the ultrasonic reception means and covers the front surface of the ultrasonic irradiation means or the ultrasonic reception means. Recording material discriminating device. A light irradiating means for irradiating the recording material with light; an image forming means for forming an image of reflected light irradiated from the light irradiating means and reflected from the recording material; and a reflected light image formed by the image forming means. Imaging means for converting to electrical signals and outputting; ultrasonic irradiation means for irradiating the recording material with ultrasonic waves; and receiving ultrasonic waves irradiated by the ultrasonic irradiation means and transmitted through the recording material to generate electrical signals. Ultrasonic wave receiving means for converting and outputting, the imaging means and the ultrasonic wave irradiating means or the front face of the ultrasonic wave receiving means are disposed and spaced from the vibrating part of the ultrasonic wave radiating means or the ultrasonic wave receiving means. A translucent plate-shaped member, a type discriminating unit for discriminating the type of the recording material based on the output of the imaging unit and the output of the ultrasonic wave receiving unit,
A recording material discriminating apparatus comprising: In the recording material discrimination device according to any one of claims 1 to 3,
Driving the ultrasonic irradiation means during the determination operation period, and driving at least one of the ultrasonic irradiation means and the ultrasonic reception means as the ultrasonic irradiation means during a period other than the determination operation period A recording material discriminating apparatus comprising means. The recording material discriminating apparatus according to claim 4, wherein
The drive means is driven with a drive voltage for discrimination operation during a discrimination operation period, and is driven with a drive voltage for foreign matter removal that combines a plurality of frequencies and amplitude voltages during a period other than the discrimination operation period. And a recording material discrimination device.   An image forming apparatus comprising the recording material discriminating apparatus according to claim 1, wherein a control parameter related to an image forming operation is changed based on a discrimination result by the recording material discriminating apparatus.

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