JP2016117560A - Recording material determination device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording material determination device which satisfies the recording material determination accuracy without loss of usability.SOLUTION: A recording material determination device comprises: a registration unit 300 which holds a conveyance guide 301 which holds a reception part 32; an oscillation guide 302 which holds a transmission part 31 and is held in an oscillating manner with respect to the registration unit 300; positioning means which positions the oscillation guide 302 with respect to the conveyance guide 301; a pressing spring 32s which energizes the oscillation guide 302 in a direction separating from the conveyance guide 301; a secondary transfer unit 23 which is supported in an oscillating manner with respect to the registration unit 300 and restricts separation of the oscillation guide 302 from the conveyance guide 301 by being energized by the pressing spring 32s; and a pressing roller 32c which is held by the oscillation guide 302 and is brought into pressure contact with the conveyance guide 301 by being energized by the pressing spring 32s. The oscillation guide 302 oscillates in conjunction with the oscillation motion of the secondary transfer unit 23.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a recording material discriminating apparatus for discriminating the characteristics of a recording material and an image forming apparatus provided with the same.

  An image forming apparatus such as a copying machine, a printer, or a facsimile machine includes 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. Have Further, the image forming apparatus includes a transfer unit that transfers the developer image developed by the developing device to the transported recording material under predetermined transfer conditions. Further, the image forming apparatus includes a fixing device that fixes the developer image onto the recording material by heating and pressing the recording material on which the developer image has been transferred by the transfer unit under predetermined fixing conditions.

  On the other hand, the size and type of the recording material are set by the user through an operation panel or the like provided in the image forming apparatus. In accordance with the setting, transfer conditions (transfer bias voltage, transport speed of recording material during transfer, etc.) and fixing conditions (fixing temperature, transport speed of recording material during fixing, etc.) are appropriately controlled.

  In order to reduce the burden of setting image forming conditions by individual users, the image forming apparatus includes a sensor for determining the characteristics of the recording material inside the image forming apparatus and has a function of automatically determining the characteristics of the recording material. Is provided. Such a discriminating apparatus automatically discriminates the characteristics of the recording material and controls the transfer conditions and fixing conditions of the image forming apparatus according to the discrimination results.

  As proposed in Patent Documents 1 and 2, the recording material discriminating apparatus irradiates the recording material with ultrasonic waves, and detects the characteristics of the ultrasonic waves that pass through the recording material. (Mass per unit area) is detected. Also, there is a type in which the surface of a recording material is irradiated with light, and the surface state (transparency, color, surface roughness, etc.) of the recording material is detected from the amount of light and distribution characteristics of the reflected light to determine the type of the recording material.

JP 2009-29622 A JP 2012-25492 A

  According to user needs, downsizing of an image forming apparatus, high accuracy of a recording material discriminating apparatus, and improvement of usability (usability) are required. However, Patent Documents 1 and 2 in which an image forming apparatus includes a recording material discriminating device that detects the characteristics of the recording material and discriminates the type of the recording material have the following problems. Although the recording material discrimination accuracy is satisfactory, there are cases where the usability of the image forming apparatus such as jam processing and exchangeability is not fully satisfied.

  The present invention solves the above-described problems, and an object of the present invention is to provide a recording material discriminating apparatus that satisfies the recording material discrimination accuracy without impairing usability.

  A typical configuration of a recording material discriminating apparatus according to the present invention for achieving the above object is a recording material discriminating apparatus in which a transmitting part and a receiving part are arranged so as to face each other across a recording material conveyance path. A first guide member that holds one of the transmitter and the receiver and guides conveyance of the recording material, a holding member that holds the first guide member, and the first guide member A second guide member that holds the other of the transmitting unit or the receiving unit that is not held by the holding unit and that is swingably held with respect to the holding member and guides the conveyance of the recording material; Positioning means for positioning the guide member with respect to the first guide member, biasing means for biasing the second guide member away from the first guide member, and rocking with respect to the holding member Movably supported The second guide member is urged by the urging means to be separated from the first guide member, and is held by the second guide member and is urged by the urging means. And a pressure contact member pressed against the first guide member, wherein the second guide member swings in conjunction with the swinging operation of the restricting means.

  According to the above configuration, the recording material discrimination accuracy can be satisfied without impairing usability.

1 is an explanatory cross-sectional view illustrating a configuration of an image forming apparatus including a recording material discrimination device according to the present invention. (A) is a front view which shows the structure of the transmission part of the recording material discrimination | determination apparatus based on this invention. (B) is a side view showing a configuration of a transmission unit of the recording material discrimination device according to the present invention. (C) is a top view which shows the structure of the transmission part of the recording material discrimination | determination apparatus based on this invention. (A) is a front view which shows the structure of the receiving part of the recording material discrimination | determination apparatus based on this invention. (B) is a side view showing the configuration of the receiving section of the recording material discriminating apparatus according to the present invention. (C) is a top view which shows the structure of the receiving part of the recording material discrimination | determination apparatus based on this invention. (A) is a plane explanatory view of the configuration of the transmission / reception unit of the recording material discrimination device according to the present invention as viewed from the direction of the secondary transfer nip portion of FIG. (B) is side explanatory drawing which shows the structure of the ultrasonic transmitter of the transmission / reception part of the recording material discrimination | determination apparatus based on this invention, and an ultrasonic receiver. (C) is side explanatory drawing which shows the structure of the light irradiation part and press roller of the transmission / reception part of the recording material discrimination | determination apparatus based on this invention. In the recording material discriminating apparatus according to the present invention, the amount of misalignment between sensors of the ultrasonic transmission device of the transmission unit and the ultrasonic reception device of the reception unit, and the ultrasonic wave from the ultrasonic transmission device of the transmission unit can be output at a constant output. It is a figure which shows the relationship with the reception output of the ultrasonic receiver of a receiver when making it transmit. In the recording material discriminating apparatus according to the present invention, the amount of misalignment between sensors of the ultrasonic transmission device of the transmission unit and the ultrasonic reception device of the reception unit, and the ultrasonic wave from the ultrasonic transmission device of the transmission unit can be output at a constant output. It is a figure which shows the relationship with the reception output of the ultrasonic receiver of a receiver when making it transmit. It is side explanatory drawing which shows the structure of 1st Embodiment of the recording material discrimination | determination apparatus which concerns on this invention. FIG. 2 is an explanatory plan view of the configuration of the first embodiment of the recording material determination device according to the present invention as viewed from the direction of the secondary transfer nip portion of FIG. 1. (A)-(c) is side explanatory drawing which shows the structure of 1st Embodiment of the recording material discrimination | determination apparatus based on this invention. It is side explanatory drawing which shows the structure of 2nd Embodiment of the recording material discrimination | determination apparatus based on this invention. FIG. 5 is an explanatory plan view of the configuration of the second embodiment of the recording material discrimination device according to the present invention as viewed from the direction of the secondary transfer nip portion of FIG. 1. (A)-(c) is sectional explanatory drawing which shows the structure of 2nd Embodiment of the recording material discrimination | determination apparatus based on this invention. It is side explanatory drawing which shows the structure of 3rd Embodiment of the recording material discrimination | determination apparatus based on this invention. FIG. 7 is an explanatory plan view of the configuration of a third embodiment of the recording material discrimination device according to the present invention as viewed from the direction of the secondary transfer nip portion of FIG. 1.

  An embodiment of a recording material discriminating apparatus according to the present invention and an image forming apparatus having the same will be described in detail with reference to the drawings.

  First, the configuration of a first embodiment of an image forming apparatus provided with a recording material discrimination device according to the present invention will be described with reference to FIGS. In the present embodiment, an example of the recording material discrimination device 9 mounted on the electrophotographic image forming apparatus 1 will be described.

<Image forming apparatus>
First, the configuration of the image forming apparatus 1 provided with the recording material discrimination device 9 according to the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional explanatory view showing the configuration of an image forming apparatus 1 provided with a recording material discrimination device 9 according to the present invention. In FIG. 1, reference numeral 2 denotes a feeding cassette that stores a recording material P such as paper. A control unit 3 is a control unit that controls the image forming operation of the image forming apparatus 1. A feeding roller 4 feeds the recording material P from the feeding cassette 2.

  Reference numeral 7 denotes a conveyance roller for conveying the fed recording material P. Reference numerals 11Y, 11M, 11C, and 11K denote photosensitive drums that serve as image carriers that respectively carry yellow (Y), magenta M, cyan C, and black K developers (toners). For convenience of explanation, the photosensitive drums 11Y, 11M, 11C, and 11K may be described by using the photosensitive drum 11 as a representative. The same applies to other image forming process means.

  Each photosensitive drum 11 is rotationally driven in the direction of arrow a in FIG. 1 by receiving a rotational driving force from a motor (not shown) provided in the main body of the image forming apparatus 1.

  Reference numerals 12Y, 12M, 12C, and 12K denote charging rollers that serve as charging means for uniformly charging the surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K to a predetermined potential. 13Y, 13M, 13C, and 13K form an electrostatic latent image by irradiating the surface of each photosensitive drum 11 uniformly charged by each charging roller 12 with laser light 13a corresponding to the image data of each color. This is a laser scanner serving as an image exposure means.

  Reference numerals 14Y, 14M, 14C, and 14K denote developing devices serving as developing means for supplying a developer (toner) to the electrostatic latent image formed on the surface of each photosensitive drum 11 to develop and visualize the image. 15Y, 15M, 15C, and 15K are rotatably provided in each developing device 14, and the developer (toner) accommodated in the developing device 14 is converted into an electrostatic latent image formed on the surface of each photosensitive drum 11. A developing roller for supplying and developing.

  Reference numerals 16Y, 16M, 16C, and 16K denote primary transfer rollers serving as primary transfer means for primarily transferring toner images of respective colors formed on the surface of the respective photosensitive drums 11 onto the outer peripheral surface of the intermediate transfer belt 17. The intermediate transfer belt 17 carries the toner images of the respective colors, which are primarily transferred sequentially from the surface of each photosensitive drum 11 by the respective primary transfer rollers 16, in a superimposed manner. The intermediate transfer belt 17 is stretched around a drive roller 18, a tension roller 25, and a secondary transfer counter roller 20 so as to be rotatable.

  The driving roller 18 receives a rotational driving force from a motor (not shown) provided in the main body of the image forming apparatus 1 and rotates the intermediate transfer belt 17 in the direction of arrow b in FIG. The tension roller 25 applies tension to the intermediate transfer belt 17. A secondary transfer roller 19 serving as a secondary transfer unit is provided opposite to the intermediate transfer belt 17 wound around the secondary transfer counter roller 20. The secondary transfer roller 19 secondarily transfers the toner image primarily transferred onto the outer peripheral surface of the intermediate transfer belt 17 onto the recording material P.

  A fixing device 21 serves as a fixing unit. The fixing device 21 heats and pressurizes the recording material P onto which the toner image on the outer peripheral surface of the intermediate transfer belt 17 is secondarily transferred by the fixing roller and the pressure roller. Thus, the toner image secondarily transferred onto the recording material P is melted and fixed on the surface of the recording material P.

  A discharge roller 22 discharges the recording material P on which the toner image is fixed by the fixing device 21 onto the discharge tray 26. A switchback roller 27 re-feeds the recording material P to the double-sided path 10 when printing on both sides of the recording material P.

  The control unit 3 is provided with a CPU (Central Processing Unit) 80. The CPU 80 collectively controls the image forming operation of the image forming apparatus 1. Print data including a print command, image information, and the like is input to the control unit 3 from a host computer (not shown). Then, the image forming apparatus 1 starts an image forming operation. The recording material P stacked on an unillustrated intermediate plate that can be moved up and down of the feeding cassette 2 is fed out by a feeding roller 4, separated and fed one by one in cooperation with a separating means (not shown), and a conveyance path 8. Sent out. The recording material P is continuously fed by the feeding roller 4 and the conveying roller 7 in synchronization with the position of the toner image on the outer peripheral surface of the intermediate transfer belt 17 and the conveying timing.

<Image forming operation>
In synchronism with the operation in which the recording material P is fed by the feeding roller 4 and the conveying roller 7, the following series of image forming operations for forming a toner image on the recording material P by the image forming means described above are performed. First, the surface of each photosensitive drum 11 is charged to a constant potential by each charging roller 12. Based on the print data input to the control unit 3, laser light 13a emitted from each laser scanner 13 is exposed and scanned onto the surface of each photosensitive drum 11 uniformly charged by each charging roller 12, and each photosensitive drum 11 is scanned. An electrostatic latent image is formed on the surface.

  A developer (toner) is supplied to the electrostatic latent image formed on the surface of each photosensitive drum 11 by each developing roller 15 of each developing device 14 and developed, and visualized as a toner image of each color. The surface of each photosensitive drum 11 is in contact with the outer peripheral surface of the intermediate transfer belt 17. Each photosensitive drum 11 rotates in the direction of arrow a in FIG. 1 in synchronization with the rotational movement of the intermediate transfer belt 17 in the direction of arrow b in FIG.

  Each color toner image developed on the surface of each photosensitive drum 11 is sequentially superimposed on the outer peripheral surface of the intermediate transfer belt 17 by each primary transfer roller 16 provided on the inner peripheral surface side of the intermediate transfer belt 17. Primary transcription. The toner remaining on the surface of each photosensitive drum 11 after primary transfer onto the outer peripheral surface of the intermediate transfer belt 17 is scraped and collected by a cleaning blade provided in a cleaning unit (not shown) for the next image formation. Provided.

  The toner image (color image) primarily transferred from the surface of each photosensitive drum 11 superimposed on the outer peripheral surface of the intermediate transfer belt 17 is secondarily transferred onto the recording material P. The toner image on the outer peripheral surface of the intermediate transfer belt 17 moves with the rotation of the intermediate transfer belt 17 to the secondary transfer nip portion N where the secondary transfer roller 19 and the secondary transfer counter roller 20 face each other. Thereafter, the toner image is secondarily transferred onto the recording material P conveyed to the secondary transfer nip N.

  The toner image secondarily transferred to the recording material P is melted and fixed on the recording material P by being heated and pressed by a fixing device 21 including a fixing roller and a pressure roller. The recording material P on which the toner image has been fixed is nipped and conveyed by the discharge roller 22 and the switchback roller 27 and discharged onto the discharge tray 26, and the normal image forming operation ends.

  Further, on the outer peripheral surface of the intermediate transfer belt 17, a cleaning blade 35 serving as a cleaning member provided in a cleaning device 36 serving as a cleaning unit is abutted. The toner remaining on the outer peripheral surface of the intermediate transfer belt 17 after being secondarily transferred to the recording material P is scraped off and collected by the cleaning blade 35 and used for the next image formation.

  When printing on both sides of the recording material P in the image forming apparatus 1, the recording material P that has finished the image forming operation on the first side is sandwiched and conveyed by the discharge roller 22 and the switchback roller 27, and is recorded on the recording material P. Are discharged out of the main body of the image forming apparatus 1. Thereafter, when the rear end of the recording material P passes through a double-sided flapper (not shown), the double-sided flapper is switched to the double-sided path 10 indicated by the dotted line in FIG. The recording material P is conveyed to the double-sided path 10 by rotating in the reverse direction.

  Thereafter, the inside of the double-sided path 10 is conveyed by the conveying rollers 33 and 34, reversed, and fed again by the conveying roller 7. Then, after the image forming operation on the second surface is performed in the same manner as the image forming operation on the first surface of the recording material P, the recording material P is nipped and conveyed by the discharge roller 22 and the switchback roller 27 and is placed on the discharge tray 26. The two-sided image forming operation is finished.

  Further, the image formation of the recording material P loaded on the manual feed tray 28 provided on the side surface portion of the image forming apparatus 1 is instructed. Then, the recording material P loaded on the manual feed tray 28 is fed by a feed roller (not shown) and joins the double-sided path 10. Then, after performing the image forming operation as described above, the recording material P is nipped and conveyed by the discharge roller 22 and the switchback roller 27 and discharged onto the discharge tray 26, and the image forming operation is completed.

<Recording material discrimination device>
Next, the configuration of the recording material discrimination device 9 will be described with reference to FIGS. As shown in FIG. 1, the recording material P is transported upstream of the secondary transfer nip N where the secondary transfer roller 19 and the secondary transfer counter roller 20 on the transport path 8 serving as a recording material transport path face each other. Is provided with a recording material discrimination device 9. The recording material discriminating apparatus 9 of this embodiment discriminates the type of the recording material P by detecting the surface state (transparency, color, surface roughness, etc.) and basis weight of the recording material P conveyed on the conveyance path 8. To do.

  As shown in FIG. 1, the recording material discrimination device 9 according to the present embodiment includes a transmission unit 31 that is a transmission unit and a reception unit 32. The transmission unit 31 and the reception unit 32 are provided so as to sandwich the conveyance path 8 for conveying the recording material P in the registration unit 300 serving as a holding member. On one side of the transport path 8, a transmission unit 31 that transmits ultrasonic waves is provided. On the other side of the transport path 8, a receiving unit 32 that receives ultrasonic waves transmitted from the transmitting unit 31 is provided.

  The recording material discriminating apparatus 9 according to the present embodiment is arranged so that the transmission unit 31 serving as a transmission unit and the reception unit 32 face each other across the conveyance path 8 serving as a recording material conveyance path.

  FIG. 2A is a front view showing the configuration of the transmission unit 31 of the recording material discrimination device 9. FIG. 2B is a side view showing the configuration of the transmission unit 31 of the recording material discrimination device 9. FIG. 2C is a plan view showing the configuration of the transmission unit 31 of the recording material discrimination device 9. FIG. 3A is a front view showing the configuration of the receiving unit 32 of the recording material discriminating apparatus 9. FIG. 3B is a side view showing the configuration of the receiving unit 32 of the recording material discriminating apparatus 9. FIG. 3C is a plan view showing the configuration of the receiving unit 32 of the recording material discriminating apparatus 9.

  As shown in FIGS. 2A to 2C, the transmission unit 31 of the recording material discrimination device 9 is configured by mounting an ultrasonic transmission device 31b on an electric board 31a. As shown in FIGS. 3A to 3C, the receiving unit 32 of the recording material discriminating apparatus 9 is provided with an ultrasonic receiving device 32a and a light irradiating unit 32b. The light irradiation unit 32b is provided with a light emitting unit and a light receiving unit (not shown), and light emitted from the light emitting unit is reflected by the surface of the recording material P conveyed through the conveyance path 8 and received by the light receiving unit. .

  The controller 3 detects the surface state of the recording material P based on the light quantity and distribution characteristics of the reflected light received by the light receiving unit. The relationship between the light quantity and distribution characteristics of the reflected light received by the light receiving part of the light irradiation part 32b and the surface state of the recording material P is stored in advance in a memory 29 serving as a storage means. Thereby, the control part 3 can detect the surface state of the recording material P based on the light quantity and distribution characteristic of the reflected light received by the light irradiation part 32b light-receiving part.

  FIG. 4A is an explanatory plan view of the configuration of the transmission unit 31 and the reception unit 32 of the recording material discrimination device 9 as viewed from the direction of the secondary transfer nip N in FIG. FIG. 6B is a side explanatory view showing the configuration of the ultrasonic transmission device 31b provided in the transmission unit 31 of the recording material discrimination device 9 and the ultrasonic reception device 32a provided in the reception unit 32. (C) is a side explanatory view showing a configuration of a light irradiation unit 32b provided in the reception unit 32 of the recording material discrimination device 9 and a pressing roller 32c serving as a pressure contact member.

  As shown in FIGS. 4A and 4B, the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 interpose a conveyance path 8 through which the recording material P is conveyed. Are arranged opposite to each other. Further, as shown in FIGS. 4A and 4C, a pressing roller 32c is rotatably provided facing the light irradiation unit 32b of the receiving unit 32. The rotating shaft 32d of the pressing roller 32c is pressed in a direction toward the light irradiation unit 32b of the receiving unit 32 by receiving a biasing force by a pair of pressing springs 32s serving as a biasing unit.

  The pressing roller 32c is rotatably supported by a swing guide 302 serving as a second guide member shown in FIG. The recording material P is sandwiched between the registration roller 5 and the driven roller 6 and is conveyed in the direction of arrow Z in FIG. The conveying force of the recording material P is transmitted to the pressing roller 32c through the frictional force between the surface of the recording material P and the surface of the pressing roller 32c, and the pressing roller 32c is driven to rotate in the direction of arrow R2 in FIG. .

  The ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 shown in FIG. 4A are a piezoelectric element (piezo element) that is an interconversion element between a mechanical displacement and an electric signal. The electrode terminal is configured similarly. In the ultrasonic transmission device 31b of the transmission unit 31, a pulse voltage having a predetermined frequency is input to the electrode terminal. Then, the piezoelectric element oscillates and ultrasonic waves are generated and propagate in the air. When the ultrasonic wave transmitted from the ultrasonic transmission device 31b of the transmission unit 31 reaches the recording material P conveyed through the conveyance path 8, the recording material P is ultrasonically vibrated by the ultrasonic wave.

The ultrasonic wave transmitted from the ultrasonic transmission device 31b of the transmission unit 31 is received by the ultrasonic reception device 32a of the reception unit 32 via the recording material P. The piezoelectric element provided in the ultrasonic receiving device 32a corresponds to the amplitude of the received ultrasonic wave according to the basis weight of the recording material P (mass per unit area (g / m ² ) of the recording material P). An output voltage is generated at the electrode terminals. The control unit 3 detects the basis weight of the recording material P based on the output voltage generated at the electrode terminal of the ultrasonic receiving device 32a. By storing the relationship between the output voltage generated at the electrode terminal of the ultrasonic receiving device 32a and the basis weight of the recording material P in the memory 29 serving as a storage unit in advance, the control unit 3 allows the ultrasonic receiving device 32a. The basis weight of the recording material P can be detected based on the output voltage generated at the electrode terminals.

  The control unit 3 uses the recording material P conveyed through the conveyance path 8 between the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 shown in FIG. The basis weight of the recording material P is detected by transmitting and receiving ultrasonic waves. Further, the control unit 3 reflects the light emitted from the light emitting unit provided in the light irradiation unit 32b shown in FIG. 4A to the surface of the recording material P conveyed through the conveyance path 8 and is received by the light receiving unit. The surface state of the recording material P is detected based on the amount of reflected light and the distribution characteristics.

  Then, based on the basis weight of the recording material P and the surface state, it is possible to determine the type of the recording material P that is transported through the transport path 8. By storing the relationship between the basis weight of the recording material P, the surface state, and the type of the recording material P in the memory 29 serving as a storage unit in advance, the control unit 3 allows the recording material to be transported through the transport path 8. The type of the recording material P can be determined based on the basis weight of P and the surface state.

For example, as the type of the recording material P, thin paper (basis weight: 64 g / m ² or less) and plain paper (basis weight: 65 g / m ^{2 to} 105 g / m ² ) are used. Further, medium cardboard (basis weight: 106 g / m ^{2 to} 135 g / m ² ) and large cardboard (basis weight: 136 / m ² or more) are used. Further, gloss paper (glossy paper), gloss film, OHT (Over Head Transparency) sheet (transparent sheet used for OHP (Over Head Projector)), and the like are used.

  For example, the recording material P having a large basis weight has a small output voltage generated at the electrode terminal of the ultrasonic receiving device 32a of the receiving unit 32. On the other hand, the recording material P having a small basis weight has a large output voltage generated at the electrode terminal of the ultrasonic receiving device 32a of the receiving unit 32. The control unit 3 determines the basis weight, which is one of the attributes of the recording material P, based on the output voltage generated at the electrode terminal of the ultrasonic receiving device 32a of the receiving unit 32, and determines the type of the recording material P. It can be one of the parameters for

  Further, the control unit 3 records the light emitted from the light emitting unit provided in the light irradiation unit 32b by the amount of reflected light reflected on the surface of the recording material P conveyed through the conveyance path 8 and received by the light receiving unit. It is possible to determine whether or not the material P is a transparent OHT sheet. The OHT sheet is transparent and has a light transmittance that is significantly higher than that of other recording materials P such as paper. For this reason, the amount of reflected light reflected by the surface of the recording material P and received by the light receiving portion is significantly smaller than that of other recording materials P such as paper. Therefore, based on the amount of reflected light reflected on the surface of the recording material P and received by the light receiving unit of the light irradiation unit 32b, the control unit 3 determines whether the recording material P conveyed on the conveyance path 8 is an OHT sheet or It is possible to determine whether the recording material P is another recording material P such as paper.

  Further, the coarse density state of the surface fibers varies depending on the type of the recording material P. Depending on the whiteness of the surface of the recording material P, the color of the surface of the recording material P, and the coarse density state of the paper fibers on the surface of the recording material P, the light emitted from the light emitting section provided in the light irradiation section 32b The amount of reflected light and the distribution characteristics of the reflected light reflected on the surface of the recording material P being conveyed and received by the light receiving unit are different.

  The control unit 3 reflects the amount of light and the distribution characteristics of the reflected light received by the light receiving unit after the light emitted from the light emitting unit provided in the light emitting unit 32b is reflected on the surface of the recording material P conveyed through the conveyance path 8. Based on this, the type of the recording material P can be determined. For example, it is possible to discriminate rough paper (surface smoothness is low) having rough paper fibers on the surface of the recording material P. Further, it is possible to discriminate plain paper in which the recording material P is generally used (surface smoothness is higher than rough paper). Further, gloss paper (glossy paper) (surface smoothness is higher than that of plain paper) in which the fibers of the paper on the surface of the recording material P are sufficiently compressed can be discriminated.

  As described above, the control unit 3 reflects the light emitted from the light emitting unit provided in the light irradiation unit 32b on the surface of the recording material P conveyed through the conveyance path 8 and is received by the light receiving unit. The difference in the fiber state (surface state) of the paper on the surface of the recording material P is detected based on the distribution characteristics. And it can be set as one of the parameters for discriminating the kind of the recording material P.

  The control unit 3 considers the basis weight of the recording material P obtained based on the output voltage generated at the electrode terminal of the ultrasonic receiving device 32a of the receiving unit 32 shown in FIG. Further, the light quantity and distribution characteristics of the reflected light received by the light receiving part of the light irradiation part 32b are considered. Then, the type of the recording material P is determined in accordance with the detection result of the basis weight of the recording material P and the surface state of the recording material P obtained based on the amount of reflected light and the distribution characteristics. Then, the image forming conditions of the recording material P are appropriately set according to the determination result of the type of the recording material P.

  The image forming conditions of the recording material P can be set, for example, by changing the conveyance speed of the recording material P depending on the type of the recording material P, or changing the secondary transfer bias voltage applied to the secondary transfer roller 19 during the secondary transfer. Or the fixing temperature in the fixing device 21 is changed.

  In this embodiment, before the toner image on the outer peripheral surface of the intermediate transfer belt 17 is secondarily transferred to the recording material P in the secondary transfer nip portion N, the basis weight of the recording material P conveyed on the conveyance path 8 is calculated. The detection result with the surface state is obtained. As a result, the type of the recording material P conveyed through the conveyance path 8 can be determined, and an image can be formed on the recording material P under the image forming conditions optimum for the recording material P.

<Sensor position accuracy>
The ultrasonic waves transmitted from the ultrasonic transmission device 31b of the transmission unit 31 shown in FIGS. 4 (a) and 4 (b) are transmitted between the sensors of the ultrasonic transmission device 31b and the ultrasonic reception device 32a of the reception unit 32. The smaller the misalignment amount, the larger the reception output at the ultrasonic receiving device 32a of the receiving unit 32.

  5 and 6 show on the horizontal axis the amount of misalignment between sensors of the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32. FIG. Furthermore, the vertical axis represents the reception output of the ultrasonic reception device 32a of the reception unit 32 when the ultrasonic wave from the ultrasonic transmission device 31b of the transmission unit 31 is transmitted at a constant output.

  Receiving when the amount of misalignment between the sensors of the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 is “0” as in the sensor A indicated by the two-dot chain line in FIG. The reception output of the ultrasonic receiver 32a of the unit 32 is set to “100”. Then, the reception output decreases as the misalignment amount indicated by the horizontal axis in FIG.

  In general, sensors used in the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 are indicated by a sensor A indicated by a two-dot chain line in FIG. 5 and a solid line in FIG. There are individual differences as in sensor B. For this reason, in the initial state, the transmission output of the ultrasonic transmission device 31b of the transmission unit 31 is set so that the reception output of the ultrasonic reception device 32a of the reception unit 32 becomes a certain value or more.

  For example, like the sensor Bc indicated by the broken line in FIG. 6, the reception output B1 of the ultrasonic receiving device 32a of the reception unit 32 when the misalignment amount indicated by the horizontal axis in FIG. > B1) is adjusted so as to increase the transmission output of the ultrasonic transmission device 31b of the transmission unit 31. At the same time, the ultrasonic transmission device 31b of the transmission unit 31 so as to correct a decrease in the reception output due to the misalignment between the sensors of the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32. Set the transmission output of. The transmission output of the ultrasonic transmission device 31b of the transmission unit 31 set in this way is stored in the memory 29 shown in FIG.

  For example, in the sensor A indicated by the two-dot chain line in FIG. 5 and the sensor B indicated by the solid line in FIG. 6, the misalignment amount indicated by the horizontal axis in FIGS. 5 and 6 may be “S1”. At that time, the transmission output of the ultrasonic transmission device 31b of the transmission unit 31 is increased and corrected to a sensor Ac indicated by a one-dot chain line in FIG. 5 and a sensor Bc indicated by a broken line in FIG. Then, a desired reception output within the allowable range W of the reception output of the ultrasonic reception device 32a of the reception unit 32 is obtained.

  However, the misalignment amount indicated by the horizontal axis in FIGS. 5 and 6 may be “S2 (> S1)”. Similarly, the transmission output of the ultrasonic transmission device 31b of the transmission unit 31 is increased and corrected to a sensor Ac indicated by a one-dot chain line in FIG. 5 and a sensor Bc indicated by a broken line in FIG. The reception output of the ultrasonic reception device 32a of the reception unit 32 after correction cannot obtain a desired reception output within the allowable range W. Thereby, the precision which discriminate | determines the basic weight of the recording material P falls.

  Therefore, in order to accurately determine the basis weight of the recording material P, the amount of misalignment between the sensors of the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 is small (positional accuracy). Is good).

<Registration unit>
FIG. 7 is an explanatory side view showing the configuration of the registration unit 300 provided with the recording material discrimination device 9 shown in FIGS. FIG. 8 is an explanatory plan view seen from the direction of the secondary transfer nip portion N of FIG. 1 showing the configuration of the registration unit 300 provided with the recording material discrimination device 9 shown in FIGS.

  As shown in FIG. 7, the registration unit 300 serving as a holding member holds the receiving unit 32 and the driven roller 6 shown in FIG. 4A, and also guides the conveyance of the recording material P. A conveyance guide 301 serving as a member is held.

  Furthermore, the registration unit 300 serving as a holding member holds the transmission unit 31 provided in the ultrasonic transmission device 31b shown in FIG. Further, the swing guide 302 is held so as to be swingable in the direction of the arrow R1 in FIG. 7 with respect to the registration unit 300 around a rotation shaft 304 provided in the registration unit 300. The swing guide 302 is configured as a second guide member that guides the conveyance of the recording material P.

  Further, the registration unit 300 serving as a holding member has a conveyance guide 303 on which a registration roller 5 provided to face the driven roller 6 rotatably supported by the conveyance guide 301 is rotatably supported. .

  As shown in FIG. 8, the conveyance guide 301, the swing guide 302, and the conveyance guide 303 are supported by side plates 305a and 305b provided on the front side and the rear side of the registration unit 300 in FIG. ing.

  FIGS. 9A to 9C are side explanatory views showing a state in which the secondary transfer unit 23 serving as the restricting unit is swung about the rotation shaft 24 and attached to and detached from the main body of the image forming apparatus 1. It is. The secondary transfer unit 23 swings around the rotation shaft 24 with respect to the registration unit 300 fixed to the main body side of the image forming apparatus 1. The registration unit 300 is provided with a recording material discrimination device 9. A secondary transfer roller 19 is rotatably supported on the secondary transfer unit 23.

  As shown in FIG. 9A, a secondary transfer unit 23 that rotatably supports a secondary transfer roller 19 with respect to a registration unit 300 fixed to the main body side of the image forming apparatus 1 is attached to a rotation shaft 24. It is mounted by swinging (turning) in the counterclockwise direction of FIG.

  The rotation shaft 24 of the secondary transfer unit 23 is slidably inserted in an elongated hole 306 provided in the side plates 305a and 305b on which the registration unit 300 shown in FIG. 8 is supported.

  Then, as shown in FIG. 9A, the secondary transfer unit 23 is rotated counterclockwise in FIG. 9A around the rotation shaft 24 with respect to the registration unit 300 fixed to the main body side of the image forming apparatus 1. Rotate in the turning direction and attach. At that time, a positioning boss 30 provided at the end of the secondary transfer unit 23 opposite to the rotation shaft 24 is locked and fixed to a locking portion (not shown) provided on the image forming apparatus 1 main body side. Is done.

  The lock between the locking portion (not shown) provided on the main body side of the image forming apparatus 1 and the positioning boss 30 is released. Then, as shown in FIG. 9B, the secondary transfer unit 23 rotates around the rotation shaft 24 in the clockwise direction of FIG. 9B and is released from the main body of the image forming apparatus 1.

  Further, as shown in FIG. 9C, the rotation shafts 24 provided at both ends in the longitudinal direction of the secondary transfer unit 23 are provided with elongated holes 306 in the side plates 305a and 305b provided on the image forming apparatus 1 main body side. Remove from. Accordingly, the secondary transfer unit 23 can be detached from the main body of the image forming apparatus 1 independently.

<Second guide member positioning means>
Next, the configuration of the positioning means for positioning the swing guide 302 serving as the second guide member with respect to the conveyance guide 301 serving as the first guide member will be described with reference to FIGS. As shown in FIGS. 7 and 8, the swing guide 302 is moved relative to the side plates 305 a and 305 b provided on the image forming apparatus 1 main body side by the rotation shaft 304 provided in the registration unit 300 serving as a holding member. The positions in the directions of arrows X and Z in FIGS. 7 and 8 are determined.

  Further, as shown in FIG. 8, a positioning boss 307 provided on the outer side in the width direction (vertical direction in FIG. 8) of the conveyance path 8 of the recording material P of the swing guide 302 is a recess 301 a provided in the conveyance guide 301. And engage with. As a result, the position of the swing guide 302 in the direction of arrow Y in FIG. 8 is determined.

  A pressing roller 32c serving as a pressure contact member shown in FIG. 4A is held in a swing guide 302 serving as a second guide member. The pressing roller 32c is urged by a pressing spring 32s serving as a biasing means, and is rotatable in a state in which the pressing roller 32c is in pressure contact with a light irradiation unit 32b of a receiving unit 32 provided in a conveyance guide 301 serving as a first guide member. It is supported.

  As shown in FIG. 8, the rotating shaft 32 d of the pressing roller 32 c receives a biasing force from a pair of pressing springs 32 s serving as a biasing means whose one end is locked to the swing guide 302, and irradiates the light of the receiving unit 32. It is pressed in the direction toward the portion 32b. 8, the reaction force of the pressing spring 32s that urges the pressing roller 32c shown in FIG. 8 toward the light irradiation unit 32b of the receiving unit 32 acts in the direction of the arrow T1 in FIG.

  In the present embodiment, the pressing spring 32s serving as the biasing means biases the swing guide 302 serving as the second guide member in the direction of the arrow T1 in FIG. 8 away from the conveyance guide 301 serving as the first guide member.

  On the other hand, the secondary transfer unit 23 serving as the restricting means shown in FIGS. 9A to 9C is supported so as to be swingable around the rotation shaft 24 with respect to the registration unit 300 serving as the holding member. .

  As shown in FIG. 9A, the secondary transfer unit 23 is mounted on the main body of the image forming apparatus 1 by turning counterclockwise in FIG. As a result, the stopper portion 308 provided on the swing guide 302 and the receiving portion 37 provided on the secondary transfer unit 23 come into contact with each other.

  As a result, the swing guide 302 serving as the second guide member is biased by the pressing spring 32s serving as the biasing means shown in FIG. 8, and is prevented from moving away from the transport guide 301 serving as the first guide member.

  As a result, the position in the direction of arrow R1 in FIG.

  On the other hand, the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 provided in the swing guide 302 are as follows. A pair of sensors, an ultrasonic transmission device 31b and an ultrasonic reception device 32a, which are set in advance so as to obtain the reception output of the ultrasonic reception device 32a in which individual differences between sensors and the amount of misalignment are corrected, are used. .

  For example, as Comparative Example 1, a case where the ultrasonic transmission device 31b of the transmission unit 31 is directly provided in the secondary transfer unit 23 is considered. Then, it is necessary to use or replace the registration unit 300 and the secondary transfer unit 23 as a pair.

  Further, as Comparative Example 2, a case where the swing guide 302 is fixed to the registration unit 300 in order to improve the positional accuracy of the ultrasonic receiving device 32a of the receiving unit 32 is considered. Then, when the recording material P is jammed in the registration unit 300, it is difficult to jam the recording material P.

  In this embodiment, the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 are provided in the same registration unit 300 for positioning. Thereby, it is possible to improve the positional accuracy between the sensors of the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32.

  Further, as shown in FIG. 9B, the rotation shaft 24 of the secondary transfer unit 23 is provided in the registration unit 300. Further, the registration unit 300 is also provided with a rotation shaft 304 that swingably supports a swing guide 302 on which the ultrasonic transmission device 31b of the transmission unit 31 is provided. Further, an ultrasonic receiving device 32 a of the receiving unit 32 is also provided in the registration unit 300.

  Then, the receiving portion 37 provided in the secondary transfer unit 23 and the stopper portion 308 provided in the swing guide 302 abut. As a result, the rotational posture in the direction of arrow R1 in FIG. Thereby, the positional accuracy between the sensors of the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 can be improved.

  Further, as shown in FIG. 9B, the swing guide 302 rotates about the rotation shaft 304 in the clockwise direction of FIG. 9B. Then, the secondary transfer unit 23 rotates about the rotation shaft 24 in the clockwise direction of FIG. As a result, it is possible to easily perform jam processing of the recording material P jammed (paper jam) in the transport path 8 in a state where the transport path 8 is opened.

  Further, it may be necessary to replace the ultrasonic transmission device 31b of the transmission unit 31 and a part of the ultrasonic reception device 32a of the reception unit 32 which are part of the recording material determination device 9 due to a failure of each sensor. . The ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 are provided as a unit in the registration unit 300. Therefore, only the registration unit 300 can be exchanged.

  Further, as shown in FIG. 9B, when the swing guide 302 and the secondary transfer unit 23 are opened, the secondary transfer unit 23 is rotated counterclockwise in FIG. It is rotated in the turning direction and attached to the main body of the image forming apparatus 1. By this operation, the receiving portion 37 of the secondary transfer unit 23 is engaged with the stopper portion 308 of the swing guide 302, and the swing guide 302 is rotated counterclockwise in FIG. It can be mounted integrally by rotating in the direction.

  In the present embodiment, the swing guide 302 serving as the second guide member swings in conjunction with the swing operation of the secondary transfer unit 23 serving as the restricting means.

  As in this embodiment, the swing guide 302 is provided so as to be rotatable about the rotation shaft 304 with respect to the registration unit 300. This improves the positional accuracy between the sensors of the ultrasonic receiving device 32a of the receiving unit 32 provided in the registration unit 300 and the ultrasonic transmitting device 31b of the transmitting unit 31 provided in the swing guide 302. it can. Thereby, the discrimination accuracy of the recording material P by the recording material discrimination device 9 can be improved. Further, by rotating the swing guide 302 in conjunction with the swing operation of the secondary transfer unit 23 to open the transport path 8, it is possible to improve the jam handling workability of the recording material P.

  In the recording material discrimination device 9 of the present embodiment, an ultrasonic transmission / reception device including an ultrasonic transmission device 31b of the transmission unit 31 for detecting the basis weight of the recording material P and an ultrasonic reception device 32a of the reception unit 32 is provided. Provided. Furthermore, this is an example in which a light irradiation unit 32b of the receiving unit 32 for detecting the surface state of the recording material P is provided. In addition, a recording material discriminating device 9 provided with only an ultrasonic transmission / reception device may be used.

  In the present embodiment, an example in which the receiving unit 32 is provided in the conveyance guide 301 serving as the first guide member, and the transmitting unit 31 serving as the transmitting unit is provided in the swing guide 302 serving as the second guide member has been described. .

  In addition, the transmission guide 301 serving as the first guide member holds either the transmission unit or the reception unit, and the oscillation guide 302 serving as the second guide member is not held by the conveyance guide 301. Alternatively, the other receiving unit may be held.

  Further, in this embodiment, the configuration is such that the swing guide 302 shown in FIG. 7 is positioned in the direction of the arrow R1 around the rotation shaft 304 by the urging force of the pressing spring 32s shown in FIG. Alternatively, a configuration may be used in which a load such as gravity is used to position the swing guide 302 shown in FIG.

  In the present embodiment, the image forming apparatus 1 including the recording material discrimination device 9 can easily jam the recording material P while satisfying the discrimination accuracy of the recording material P. Furthermore, even when the recording material discriminating device 9 breaks down, the recording material discriminating device 9 can be easily replaced, and high usability (usability) can be applied.

  Next, the configuration of the second embodiment of the image forming apparatus provided with the recording material discrimination device according to the present invention will be described with reference to FIGS. In addition, what was comprised similarly to the said 1st Embodiment attaches | subjects the same member name even if the same code | symbol or code | symbol differs, and abbreviate | omits description.

  In the first embodiment, as shown in FIG. 8, the pressing roller 32 c receives the urging force of the rotating shaft 32 d by a pair of pressing springs 32 s serving as urging means whose one end is locked to the swing guide 302. The pressure irradiation unit 32b of the receiving unit 32 is in pressure contact.

  The pressing roller 32c is rotatably supported by the swing guide 302. The recording material P is sandwiched between the registration roller 5 and the driven roller 6 and is conveyed along the conveyance path 8 in the direction of arrow Z in FIG. The conveying force of the recording material P is transmitted to the pressing roller 32c via a frictional force between the surface of the recording material P and the surface of the pressing roller 32c. As a result, the pressing roller 32c is driven to rotate in the direction of arrow R2 in FIG.

  In the present embodiment, as shown in FIGS. 10 to 12, one end portion of the pressing spring 309 serving as the urging means is locked and held by the swing guide 302 serving as the second guide member. Further, the other end portion of the pressing spring 309 shown in FIGS. 12A to 12C abuts on a receiving portion 38 provided in the secondary transfer unit 23 serving as a receiving portion. As a result, the pressing roller 32c rotatably supported by the swing guide 302 under the urging force of the pressing spring 309 is pressed against the light irradiation unit 32b of the receiving unit 32.

  As shown in FIG. 12 (a), a pressing spring 309 serving as a biasing means having one end held by a swing guide 302 serving as a second guide member is as follows. In a state where the secondary transfer unit 23 serving as a receiving portion is mounted on the main body of the image forming apparatus 1, the swing guide 302 is urged in a direction toward the transport guide 301 serving as the first guide member.

  The secondary transfer unit 23 serving as a receiving portion is supported so as to be swingable about the rotation shaft 24 with respect to the registration unit 300 serving as a holding member.

  Then, as shown in FIG. 12A, the secondary transfer unit 23 serving as a receiving portion is mounted on the main body of the image forming apparatus 1 as follows. The receiving portion 38 provided in the secondary transfer unit 23 receives the other end portion on the side opposite to the one end portion held by the swing guide 302 serving as the second guide member of the pressing spring 309 serving as the biasing means.

  The pressing roller 32c serving as a pressure contact member is held by a swing guide 302 serving as a second guide member. Then, as shown in FIG. 12A, in a state where the secondary transfer unit 23 serving as a receiving portion is mounted on the main body of the image forming apparatus 1, the pressing roller 32c is caused by the extension force of the pressing spring 309 serving as a biasing unit. It is urged and brought into pressure contact with the conveyance guide 301 serving as the first guide member.

  In the present embodiment, a rocking guide 302 serving as a second guide member is provided in the registration unit 300 in conjunction with a rocking motion around the rotation shaft 24 of the secondary transfer unit 23 serving as a receiving portion. Oscillate about the rotating shaft 304.

  FIG. 10 is an explanatory side view showing the configuration of the registration unit 300 provided with the recording material discrimination device 9 of the present embodiment. FIG. 11 is an explanatory plan view seen from the direction of the secondary transfer nip portion N of FIG. 1 showing the configuration of the registration unit 300 provided with the recording material discrimination device 9 of the present embodiment.

  In the first embodiment, as shown in FIG. 8, the positioning of the swing guide 302 of the registration unit 300 is performed by pressing the pressing roller 32c in the direction toward the light irradiation unit 32b of the receiving unit 32. The reaction force in the direction of arrow T1 is used. Then, positioning was performed by contacting the stopper portion 308 of the swing guide 302 with the receiving portion 37 of the secondary transfer unit 23.

  In the present embodiment, as shown in FIG. 10, the registration unit 300 includes a conveyance guide 301 that holds the receiving unit 32 shown in FIG. 4A and the driven roller 6. Further, a swinging guide 302 is provided which holds the transmitting unit 31 provided with the ultrasonic transmitting device 31b and is pivotable in the direction of arrow R1 in FIG. Have In addition, a conveyance guide 303 that rotatably supports the registration roller 5 is provided.

  As shown in FIG. 11, the conveyance guide 301, the swing guide 302, and the conveyance guide 303 are supported by side plates 305a and 305b provided on the front side and the rear side of the registration unit 300 in FIG. ing.

  12A to 12C show a state in which the secondary transfer unit 23 is rotated with respect to the registration unit 300 about the rotation shaft 24 and is attached to and detached from the main body of the image forming apparatus 1. FIG. The registration unit 300 is fixed to the image forming apparatus 1 main body side. The registration unit 300 is provided with a recording material discrimination device 9. A secondary transfer roller 19 is rotatably supported on the secondary transfer unit 23.

  As shown in FIG. 12 (a), a secondary transfer roller 19 is rotatably supported on a registration unit 300 provided with a recording material discriminating device 9 fixed on the main body side of the image forming apparatus 1. A transfer unit 23 is mounted. Rotating shafts 24 are provided at both ends in the longitudinal direction of the secondary transfer unit 23. The rotation shaft 24 is slidably inserted into an elongated hole 306 provided in the side plates 305a and 305b of the registration unit 300 provided in the main body of the image forming apparatus 1.

  A positioning boss 30 is provided at the end of the secondary transfer unit 23 opposite to the rotation shaft 24. Then, as shown in FIG. 12A, the secondary transfer unit 23 is moved counterclockwise in FIG. 12A around the rotation shaft 24 with respect to the registration unit 300 fixed to the image forming apparatus 1 main body side. Rotate in the turning direction and attach At that time, the positioning boss 30 of the secondary transfer unit 23 is locked and fixed to a locking portion (not shown) provided on the image forming apparatus 1 main body side.

  The lock between the locking portion (not shown) provided on the main body side of the image forming apparatus 1 and the positioning boss 30 is released. As a result, as shown in FIG. 12B, the secondary transfer unit 23 rotates around the rotation shaft 24 in the clockwise direction in FIG. 12B and opens to the main body of the image forming apparatus 1. be able to.

  Also, as shown in FIG. 12C, the secondary transfer unit 23 is made independent by removing the rotating shaft 24 of the secondary transfer unit 23 from the long holes 306 provided in the side plates 305a and 305b of the registration unit 300. Then, the image forming apparatus 1 can be detached from the main body.

<Second guide member positioning means>
Next, the configuration of the positioning means of the swing guide 302 of this embodiment will be described with reference to FIGS. As shown in FIG. 10, the swing guide 302 of this embodiment is provided so as to be swingable in the direction of arrow R1 in FIG. As a result, the positions in the directions of arrows X and Z in FIG. 10 are determined with respect to the side plates 305a and 305b shown in FIG. 11 provided in the main body of the image forming apparatus 1.

  Further, as shown in FIG. 11, in the longitudinal direction of the swing guide 302 (vertical direction in FIG. 11), the positioning boss is positioned outside the conveyance path 8 through which the largest recording material P used in the image forming apparatus 1 passes. 307 is provided. The positioning boss 307 is engaged with and engaged with a recess 301 a provided in the conveyance guide 301. Thereby, the position in the arrow Y direction in FIG. 11 is determined.

  As shown in FIGS. 10 to 12, a pressing spring 309 serving as an urging means is locked to the surface of the swing guide 302 opposite to the surface facing the conveyance guide 301. FIG. 12B shows a state in which the swing guide 302 is pivoted about the pivot shaft 304 in the clockwise direction of FIG. From this state, the secondary transfer unit 23 is rotated counterclockwise in FIG.

  As a result, as shown in FIG. 12A, the other end of the pressing spring 309 whose one end is locked to the swing guide 302 abuts and engages with the receiving portion 38 provided in the secondary transfer unit 23. .

  As a result, the swing guide 302 is moved around the rotation shaft 304 via the pressing spring 309 in conjunction with the secondary transfer unit 23 that rotates counterclockwise in FIG. It rotates in the counterclockwise direction of FIG. Then, the positioning boss 30 provided on the secondary transfer unit 23 is locked to the locking portion provided on the main body of the image forming apparatus 1, and the secondary transfer unit 23 is attached to the main body of the image forming apparatus 1.

  At that time, as shown in FIG. 11, the positioning boss 307 of the swing guide 302 is engaged with and engaged with the recess 301 a of the conveyance guide 301. Then, the secondary transfer roller 19 rotatably supported by the secondary transfer unit 23 is pressed against the secondary transfer counter roller 20 with the intermediate transfer belt 17 interposed therebetween.

  As shown in FIG. 12 (a), the other end of the pressing spring 309 whose one end is locked to the swing guide 302 abuts on the receiving portion 38 of the secondary transfer unit 23. The pressure spring 309 is compressed against the extension force.

  On the other hand, the rotation shaft 24 of the secondary transfer unit 23 is slidably fitted in a long hole 306 formed in the side plates 305a and 305b provided in the main body of the image forming apparatus 1. Further, the positioning boss 30 of the secondary transfer unit 23 is locked and fixed to a locking portion provided in the main body of the image forming apparatus 1.

  As a result, the urging force generated by the extension force of the pressing spring 309 generates a reaction force in the direction of the arrow T2 in FIG. As a result, the positioning boss 307 of the swing guide 302 is brought into contact with the wall surface of the recess 301a of the transport guide 301, and the position in the direction of the arrow R1 in FIG.

  At this time, the pressing roller 32c rotatably supported by the swing guide 302 is brought into pressure contact with the light irradiation unit 32b of the receiving unit 32. Further, the ultrasonic transmission device 31 b of the transmission unit 31 provided in the swing guide 302 is disposed to face the ultrasonic reception device 32 a of the reception unit 32 provided in the conveyance guide 301.

  In the present embodiment, as illustrated in FIG. 12B, the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 are provided in the same registration unit 300. Thereby, the positional accuracy between the sensors of the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 can be improved.

  10 is determined by fitting the positioning boss 307 of the swing guide 302 with the recess 301a of the transport guide 301. As shown in FIG. By contact. Thereby, the positional accuracy between the sensors of the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a of the reception unit 32 can be improved.

  Further, as shown in FIG. 12B, the opening / closing operation of the swing guide 302 can be performed integrally with the opening / closing operation of the secondary transfer unit 23. Thereby, when a conveyance jam (paper jam) of the recording material P occurs in the conveyance path 8, a user can easily perform a jam processing operation.

  In addition, the ultrasonic transmission device 31b of the transmission unit 31 provided in the swing guide 302, the ultrasonic reception device 32a of the reception unit 32 provided in the conveyance guide 301, the light irradiation unit 32b, etc. are replaced due to failure of each sensor. It may be necessary. In that case, the ultrasonic transmission device 31b of the transmission unit 31 and the ultrasonic reception device 32a and the light irradiation unit 32b of the reception unit 32 constituting the recording material determination device 9 are provided integrally in the registration unit 300. It has been. Therefore, it is possible to replace the recording material discriminating apparatus 9 by exchanging only the registration unit 300.

  As a result, it is possible to improve the discrimination accuracy of the recording material P by the recording material discrimination device 9 and workability such as jamming of the recording material P jammed in the transport path 8 and replacement of the recording material discrimination device 9.

  In the recording material discrimination device 9 of the present embodiment, an ultrasonic transmission device 31b for detecting the basis weight of the recording material P and an ultrasonic reception device 32a are provided, and light for detecting the surface state of the recording material P is provided. The example which provided the irradiation part 32b was demonstrated. In addition, the recording material discriminating device 9 can be configured by providing only the ultrasonic transmission device 31b for detecting the basis weight of the recording material P and the ultrasonic reception device 32a.

  Further, in this embodiment, the positioning boss 307 of the swing guide 302 urged by the pressing spring 309 to position the swing guide 302 in the direction of the arrow R1 in FIG. It is an example performed by contact | abutting fitting. In addition, other loads such as gravity can be used instead of the urging force of the pressing spring 309.

  Further, in the present embodiment, an example in which the pressing spring 309 that generates the urging force is provided in the swing guide 302 has been described. In addition, one end portion of the pressing spring 309 may be locked on the secondary transfer unit 23 side, and a receiving portion for receiving the other end portion of the pressing spring 309 may be provided on the swing guide 302 side.

  In such a configuration, the pressing spring 309 serving as a biasing unit biases the swing guide 302 serving as the second guide member in a direction toward the conveyance guide 301 serving as the first guide member.

  Further, the secondary transfer unit 23 serving as a holding unit holds a pressing spring 309 serving as a biasing unit, and is supported so as to be swingable about the rotation shaft 24 with respect to the registration unit 300 serving as a holding member.

  The pressing roller 32c serving as a pressure contact member is held by a swing guide 302 serving as a second guide member, and is urged by a pressing spring 309 serving as a biasing unit and is pressed against a conveyance guide 301 serving as a first guide member. The

  The swing guide 302 serving as the second guide member swings about the rotation shaft 304 in conjunction with the swing operation about the rotation shaft 24 of the secondary transfer unit 23 serving as the holding portion. Other configurations are the same as those in the first embodiment, and the same effects can be obtained.

  Next, the configuration of a third embodiment of the image forming apparatus provided with the recording material discrimination device according to the present invention will be described with reference to FIGS. In addition, what was comprised similarly to each said embodiment attaches | subjects the same member name even if the same code | symbol or a code | symbol differs, and abbreviate | omits description.

  FIG. 13 is an explanatory side view showing the configuration of the registration unit 300 of this embodiment. FIG. 14 is an explanatory plan view of the configuration of the registration unit 300 of this embodiment as viewed from the direction of the secondary transfer nip N in FIG.

  In each of the embodiments shown in FIGS. 7 and 10, the pressing roller 32 c that is rotatably supported by the swing guide 302 and the light irradiation unit 32 b provided on the conveyance guide 301 include the pressing springs 32 s, It is energized by 309 and is always in contact. In this state, the recording material P is sandwiched between the registration roller 5 and the driven roller 6 and conveyed on the conveyance path 8 in the direction of arrow Z in FIGS.

  The pressing roller 32c is rotatably supported by the swing guide 302. The recording material P is nipped by the registration roller 5 and the driven roller 6 and is conveyed along the conveyance path 8 in the direction of arrow Z in FIGS. The conveying force of the recording material P is transmitted to the pressing roller 32c through the frictional force between the surface of the recording material P and the surface of the pressing roller 32c, and the pressing roller 32c is driven to rotate in the direction of arrow R2 in FIG. .

  On the other hand, the light irradiation unit 32 b is fixed to the reception unit 32 of the conveyance guide 301. Therefore, while the recording material P is conveyed between the light irradiation part 32b on the conveyance path 8 and the pressing roller 32c, the recording is performed by the pressing rollers 32c biased by the pressing springs 32s and 309, respectively. The material P is slid and moved while being urged by the light irradiation unit 32b.

  When the recording material P slides on the surface of the light irradiation unit 32b, electrostatic charging is generated between the recording material P and the light irradiation unit 32b. The recording material P is charged only with static electricity corresponding to the length in the conveyance direction of the recording material P. For this reason, the amount of charge accumulated in the recording material P is relatively small.

  On the other hand, new recording materials P are successively conveyed on the surface of the light irradiation unit 32b. For this reason, the amount of charge accumulated in the light irradiation portion 32b becomes large due to electrostatic charging generated by the plurality of recording materials P rubbing on the surface of the light irradiation portion 32b. Then, the recording material P is conveyed to the light irradiation unit 32b in a state where the charge charged in the light irradiation unit 32b exceeds a predetermined reference value. Then, the charge accumulated in the light irradiation unit 32b moves to the recording material P.

  The recording material P is conveyed to the secondary transfer nip N between the secondary transfer roller 19 and the outer peripheral surface of the intermediate transfer belt 17 with the electric charge received from the light irradiation unit 32b, and the outer periphery of the intermediate transfer belt 17 The toner image formed on the surface is secondarily transferred to the recording material P.

  When the toner image formed on the outer peripheral surface of the intermediate transfer belt 17 is secondarily transferred to the recording material P, the surface potential of the secondary transfer roller 19 and the potential of the toner image on the outer peripheral surface of the intermediate transfer belt 17 are transferred. Transfer is performed by the potential difference between the two. Therefore, by applying a predetermined secondary transfer bias voltage to the secondary transfer roller 19, a potential difference is generated between the surface potential of the secondary transfer roller 19 and the potential of the toner image on the outer peripheral surface of the intermediate transfer belt 17. .

  However, a case where the recording material P charged by the recording material P being rubbed on the surface of the light irradiation unit 32 b is conveyed to the secondary transfer roller 19 is considered. In this case, even if a preset secondary transfer bias voltage is applied to the secondary transfer roller 19, a desired potential difference cannot be obtained on the recording material P. For this reason, the toner image formed on the outer peripheral surface of the intermediate transfer belt 17 cannot be properly secondarily transferred to the recording material P, and an image defect occurs. Therefore, it is necessary to prevent charges from being accumulated in the light irradiation unit 32b.

  In this embodiment, as shown in FIG. 13 and FIG. 14, a static elimination member 310 is provided that is in electrical contact with the light irradiation part 32b of the reception part 32 held by the conveyance guide 301 serving as the first guide member. Yes. A conductive wire (not shown) is connected to the charge removal member 310, and the wire is grounded to the apparatus frame of the main body of the image forming apparatus 1.

  The recording material P is nipped by the registration roller 5 and the driven roller 6 and conveyed on the conveyance path 8 in the direction of arrow Z in FIG. The charge due to electrostatic charging generated by the rubbing between the conveyed recording material P and the light irradiation unit 32b is grounded from the light irradiation unit 32b to the device frame of the main body of the image forming apparatus 1 through the charge removal member 310. As a result, no charge is accumulated in the light irradiation unit 32b. Therefore, it is possible to prevent the occurrence of image defects due to electrostatic charging that occurs due to the rubbing between the light irradiation unit 32b and the recording material P.

  In addition, when the transmission unit 31 serving as the transmission unit is held by the conveyance guide 301 serving as the first guide member, the charge removal member 310 can be provided in electrical contact with the transmission unit 31. Other configurations are the same as those in the above embodiments, and the same effects can be obtained.

23 ... Secondary transfer unit (regulating means; receiving part; holding part)
31 ... Transmitter (transmitter)
32… Receiver
32c… Pressing roller (pressure contact member)
32s… Pressing spring (biasing means)
300 ... Registration unit (holding member)
301… Conveyance guide (first guide member)
302… Oscillating guide (second guide member)

Claims (7)

In the recording material discriminating apparatus arranged so that the transmitting unit and the receiving unit face each other across the recording material conveyance path,
A first guide member for holding one of the transmitter and the receiver and guiding the conveyance of the recording material;
A holding member for holding the first guide member;
A second guide member that holds the other of the transmitting portion and the receiving portion that is not held by the first guide member and that is swingably held with respect to the holding member and guides conveyance of the recording material When,
Positioning means for positioning the second guide member with respect to the first guide member;
Biasing means for biasing the second guide member in a direction away from the first guide member;
A restricting means that is swingably supported with respect to the holding member, and that restricts the second guide member from being biased by the biasing means and being separated from the first guide member;
A pressure contact member held by the second guide member and biased by the biasing means and pressed against the first guide member;
Have
The recording material discriminating apparatus, wherein the second guide member swings in conjunction with the swinging operation of the restricting means. In the recording material discriminating apparatus arranged so that the transmitting unit and the receiving unit face each other across the recording material conveyance path,
A first guide member for holding one of the transmitter and the receiver and guiding the conveyance of the recording material;
A holding member for holding the first guide member;
A second guide member that holds the other of the transmitting portion and the receiving portion that is not held by the first guide member and that is swingably held with respect to the holding member and guides conveyance of the recording material When,
Positioning means for positioning the second guide member with respect to the first guide member;
A biasing means that is held by the second guide member and biases the second guide member in a direction toward the first guide member;
A receiving portion that is supported so as to be swingable with respect to the holding member, and that receives the other end portion opposite to the one end portion held by the second guide member of the biasing means;
A pressure contact member held by the second guide member and biased by the biasing means and pressed against the first guide member;
Have
The recording material discriminating apparatus, wherein the second guide member swings in conjunction with the swinging motion of the receiving portion. In the recording material discriminating apparatus arranged so that the transmitting unit and the receiving unit face each other across the recording material conveyance path,
A first guide member for holding one of the transmitter and the receiver and guiding the conveyance of the recording material;
A holding member for holding the first guide member;
A second guide member that holds the other of the transmitting portion and the receiving portion that is not held by the first guide member and that is swingably held with respect to the holding member and guides conveyance of the recording material When,
Positioning means for positioning the second guide member with respect to the first guide member;
Biasing means for biasing the second guide member in a direction toward the first guide member;
A holding portion that holds the urging means and is swingably supported with respect to the holding member;
A pressure contact member held by the second guide member and biased by the biasing means and pressed against the first guide member;
Have
The recording material discriminating apparatus, wherein the second guide member swings in conjunction with the swinging operation of the holding portion.   The recording material determination device according to claim 1, wherein the recording material determination device detects a basis weight of the recording material.   The recording material discrimination device according to claim 4, wherein the recording material discrimination device further detects a surface state of the recording material.   It has a static elimination member provided in electrical contact with the said transmission part or the said receiving part currently hold | maintained at said 1st guide member, The any one of Claims 1-5 characterized by the above-mentioned. Recording material discrimination device. The recording material discriminating device according to any one of claims 1 to 6,
Image forming means for forming an image on a recording material;
An image forming apparatus comprising:

Images