JP4766520B2 - Image forming device, paper type detection device - Google Patents

Description

  The present invention relates to an image forming apparatus and a paper type detection device, and more particularly, to an apparatus having a novel configuration for calling a sheet.

  In the conventional paper type detection device, when a paper type setting error is detected or when double feed is detected, the image forming operation is stopped, the paper is retained in the apparatus, and damage caused by the image forming operation is minimized. I was doing.

However, if an adherent such as paper dust, toner, or dust adheres to the LED lens of the optical system, the above function may not operate normally. If such a situation occurs, the LED lens The serviceman was cleaning the machine by removing the machine parts.
JP 2003-29581 A Japanese Patent Laid-Open No. 04-35852 JP-A-62-161135 JP 2002-205860 A

In view of the conventional problems as described above, the cleaning of the optical sensor for detecting the paper type and double feed, and an object thereof is to make can be easily performed by the operator as well as the serviceman.

An image fixing apparatus according to a first aspect of the present invention is an image forming apparatus provided with an optical sensor for detecting a paper type or double feed facing a paper conveyance path.
The optical sensor is arranged on the resist lower guide plate on the upstream side of the registration roller in the paper conveyance direction,
The registration lower guide plate is bent in a downstream portion in the paper conveyance direction on the registration roller side and in an upstream portion in the paper conveyance direction from the downstream portion, and the downstream portion The angle formed by the upstream portion with respect to the horizontal direction is larger than the angle formed with respect to the horizontal direction.
Notching the resist lower guide plate so as to transmit light from the optical member, providing a hole ;
The hole is provided across the downstream portion and the upstream portion of the resist lower guide plate in the transport direction of the paper,
The periphery of the hole and the hole, the resist lower guide plate the downstream side of the resist lower guide plate covered with a transparent film material in a portion and the upstream portion was straddle the conveying direction of the sheet of the It is characterized by eliminating the unevenness.

According to the second aspect of the present invention, in the image forming apparatus of the first aspect, an angle formed by the downstream portion of the resist lower guide plate provided with the film material with respect to a horizontal direction is 20 ° or more. It is characterized by.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, a non-adhesive coat layer is provided on the surface of the film material.

According to a fourth aspect of the present invention, in the image forming apparatus of the third aspect , the non-adhesive coat layer is a polyfluoroethylene coat layer .

According to the fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the hole has a pentagonal shape, and the downstream side portion and the upstream side portion of the lower resist guide plate site to span the conveying direction of the paper TMG along a conveying direction of the sheet, characterized by comprising coordinated vertices acute furthest downstream in the conveying direction of the paper.

The present invention relates to an image forming apparatus provided with an optical sensor for detecting paper type / multifeed, and a transparent film so as to cover a hole provided by cutting out a conveyance path so as to transmit light of the optical sensor. Since the material is affixed, it is not necessary to clean the optical sensor only by cleaning the paper dust of the film material, and there is an effect that not only the service person but also the operator can easily perform the cleaning.

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  In FIG. 1, an image forming apparatus 1 is disposed substantially at the center of the color image forming apparatus, and a paper feeding section 2 is disposed immediately below the image forming section 1. The paper feed unit 2 includes a paper feed cassette 21 at each stage. If necessary, another paper feeding device 22 such as a mass paper feeding device can be added. Above the image forming unit 1, a reading unit 3 for reading a document is arranged. A paper discharge storage unit 4 is provided on the left side of the image forming unit 1 in the drawing, and discharges and stores a recording medium (hereinafter referred to as paper) on which an image is formed.

  In the image forming unit 1, two image forming units 6 and 6 are arranged around a belt-like intermediate transfer belt 5. In each image forming unit 6, a charging device 62 that performs charging processing on the surface of the photoconductor 61 around the drum-shaped photoconductor 61, an exposure device 7 that irradiates the surface of the photoconductor 61 with laser light with image information, Two developing devices 63 for visualizing the electrostatic latent image formed on the surface of the photoconductor 61 and a cleaning device 64 for removing and collecting the remaining toner on the photoconductor 61 are arranged. The intermediate transfer belt 5 rotates to form one color image.

  As an operation, first, yellow (Y) toner is developed in the yellow (Y) image forming section and transferred to the intermediate transfer belt. Next, the magenta (M) image forming unit develops the magenta toner and transfers it to the intermediate transfer belt. Next, cyan toner is developed in the cyan (C) image forming section and transferred to the intermediate transfer belt, and finally black (BK) toner is developed and transferred to the intermediate transfer belt.

  A transfer device 51 for transferring the four color toner images developed on the intermediate transfer belt 5 to a sheet and an intermediate transfer cleaning device 52 for removing and collecting the toner remaining on the surface of the intermediate transfer belt after transfer are arranged.

  A fixing device 8 for fixing the toner on the paper on which the toner image has been obtained is disposed downstream of the image forming apparatus (means) in the paper transport direction (downstream in the paper transport path). The sheet that has passed through the fixing device 8 is discharged and stored in the discharge storage unit 4 by the discharge roller 41.

  At the time of double-sided printing on paper, the paper is branched by the branching unit 92 and sent to the double-sided device 93, the paper is reversed via the device, the paper skew is corrected by the registration roller 23, and the image is formed on the back side. It leads to operation.

  In the paper feed unit 2, unused paper is stored in the paper feed cassette 22, and the bottom plate that is rotatably supported raises the uppermost paper to a position where the pickup roller can contact. As the paper feed roller rotates, the uppermost paper is fed from the paper feed cassette 22 and conveyed to the registration roller 23. The registration roller 23 temporarily stops the conveyance of the sheet, and controls the rotation to start at a timing so that the positional relationship between the toner image on the surface of the photosensitive member 61 and the leading edge of the sheet becomes a predetermined position.

  In the reading unit 3, in order to read and scan a document (not shown) placed on the contact glass 31, the reading traveling bodies 32 and 33 including a document illumination light source and a mirror reciprocate. Image information obtained by scanning by the reading traveling bodies 32 and 33 is read as an image signal into the CCD 35 installed behind the lens 34. The read image signal is digitized and processed. Based on the image-processed signal, an electrostatic latent image is formed on the surface of the photoreceptor 61 by light emission of a laser diode LD (not shown) in the exposure device 7. The optical signal from the laser diode LD reaches the photosensitive member 61 via a known polygon mirror or lens. An automatic document feeder 3 that automatically feeds a document onto the contact glass can be attached above the reading unit 3.

  The color image forming apparatus according to this embodiment scans and reads an original as described above, digitizes it, and copies it on a sheet of paper. This is a multi-function image forming apparatus having a facsimile function for exchanging information with a remote place and a so-called printer function for printing image information handled by a computer on paper. All images formed by any function are discharged and stored in one discharge storage unit 4.

  When the paper is branched by the branching unit 92 and reversed through the double-sided device 93 and discharged from the paper discharge roller 41 through the reverse paper discharge roller, the paper stacked in the paper discharge storage unit has an image surface. Even if the copy, facsimile, and printer manuscripts are processed from the first page and printed out, the first page is the top when it is taken out from the paper storage unit. Freed from work such as aligning pages.

  According to the present invention, the LED 101 portion for detecting the paper type and double feed in the resist upstream portion (see FIG. 2) of the image forming apparatus described above is formed into a resist lower guide shape that can be easily cleaned by an operator. It also reduces the frequency of cleaning. 2 denotes a light receiving portion for emitting light from the LED 101, 103 denotes a supporting portion thereof, and 105 denotes an upper sheet guide.

In this embodiment, as shown in FIG. 3, in the image forming apparatus provided with the LED 101 which is an optical sensor for detecting the paper type / multiple feed, the resist lower guide plate 104 (hereinafter simply referred to as “light guide LED”) is transmitted . As shown in FIG. 4, a transparent film 106 is pasted and covered in a hole provided with a notch in the guide plate 104), and the unevenness of the guide plate 104 is eliminated. The guide plate 104 is bent at a downstream portion in the paper conveyance direction on the registration roller 23 side and an upstream portion in the paper conveyance direction from the downstream portion, and the downstream portion is in the horizontal direction. The angle formed by the upstream portion with respect to the horizontal direction is larger than the angle formed with respect to the horizontal direction, and the holes are formed in the downstream portion and the upstream portion of the guide plate 104. The guide plate 104 is provided so as to straddle in the transport direction, and the hole and the periphery of the hole are covered with a transparent film 106 so as to straddle the downstream portion and the upstream portion of the guide plate 104 in the paper transport direction. The unevenness is eliminated.

  For this reason, paper dust does not enter the lens of the LED portion, and therefore it is not necessary to clean the lens, and it is possible to prevent the light of the LED from being blocked by the paper dust only by cleaning the paper dust of the film 106. Further, since the unevenness of the guide plate 104 is eliminated, it can be easily cleaned with a cloth or the like.

As shown in the figure, the hole through which the light of the LED 101 can be transmitted has a pentagon (the shape of the hole is such that the portion that extends between the downstream portion and the upstream portion of the guide plate 104 in the paper transport direction is the width of the paper. Along the conveyance direction, an acute apex is arranged on the most downstream side in the conveyance direction of the paper.) A transparent PET film with a thickness of, for example, 0.1 mm is pasted so as to cover the hole. The PET film is attached by attaching a double-sided tape in advance to a place other than the five-sided holes. Since the guide plate 104 is often made of metal, this method of attachment is effective, but it goes without saying that other materials and methods may be used.

  In addition, as shown in FIG. 5, when the angle θ between the film 106 and the horizontal is set to 20 ° or more, the paper powder automatically rolls or slides down on the transparent film 106 such as PET due to its inclination, Less frequent cleaning.

The static friction coefficient μs of the PET film 106 is desirably 0.2 to 0.3. The angle θ at which the paper powder falling on such a PET film slides is expressed by the following equation.
μs = W · sin θ / W · cos θ = tan θ
μs is a coefficient of static friction. Therefore, θ = tan ⁻¹ μs
θ1 = tan ⁻¹ (0.2) = 11 °
θ2 = tan ⁻¹ (0.3) = 17 °
It becomes. That is, when the static friction coefficient μs is 0.2 to 0.3, the paper powder slides down at an angle θ of 11 ° to 17 °.

  FIG. 6 is a cross-sectional view showing a configuration in which a non-adhesive coat layer 107 is provided on the surface of the film 106. When the non-adhesive coat layer 107 is provided on the surface of the film 106, the coefficient of friction of the sheet decreases, the paper powder easily falls, and the paper powder containing calcium carbonate or the like hardly adheres to the surface of the film 106. For this reason, the effect of falling paper paper and sliding down can be maintained over time.

  A polyfluorinated ethylene coating layer can be used as the non-adhesive coating layer 107. The difference between polyethylene and polyfluorinated ethylene is apparently (H) hydrogen and (F) fluorine. However, in polyethylene, even if it adheres to carbon atoms with small hydrogen, it becomes uneven, but fluorine is a large atom, so when it sticks to carbon atoms, it becomes a dense and smooth surface as shown in FIG. In addition, the cohesive energy between molecules (the force that binds the molecules) is also smaller than that of polyethylene, so the surface energy is low, adhesion is difficult to occur, and friction is reduced. Of course, the cohesive energy is small even between the internal molecules, so it becomes easy to slip. That is, the advantages of “not sticking” and “smooth” are synergistic, and paper powder containing calcium carbonate or the like is particularly difficult to adhere to the transparent film. The coefficient of static friction μs of polyfluorinated ethylene is 0.05 to 0.1, and even if the inclination θ is about 2.9 ° to 5.7 °, the paper dust starts to slide down. Is less likely to accumulate and the frequency of cleaning is reduced.

Sectional drawing which shows one Example of the image forming apparatus which concerns on this invention Sectional drawing which shows the resist upstream part of the image forming apparatus of FIG. The perspective view which shows the guide board which has not stuck the film and the hole is exposed Perspective view of the configuration with a transparent film pasted to eliminate the unevenness of the guide plate Sectional drawing which shows angle (theta) which the film stuck on the guide plate makes with the horizontal Sectional drawing which shows the structure of the film which provided the non-adhesive coating layer on the surface Diagram showing the molecular structure of polyethylene and Teflon (registered trademark)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming part 2 Paper feed part 3 Reading part 4 Discharge storage part 5 Intermediate transfer belt 6 Image forming part 7 Exposure device 8 Fixing device 21 Paper feed cassette 22 Paper feed device 23 Registration roller 31 Contact glass 32, 33 Reading run Body 34 Lens 35 CCD
41 discharge roller 51 transfer device 52 intermediate transfer cleaning device 61 photoconductor 62 charging device 63 developing device 64 cleaning device 92 branching unit 93 double-sided device 101 LED
102 light receiving portion 103 support portion 104 guide plate 105 paper guide 106 film 107 coat layer

Claims (5)

In an image forming apparatus equipped with an optical sensor for detecting the paper type and double feed facing the paper conveyance path,
The optical sensor is arranged on the resist lower guide plate on the upstream side of the registration roller in the paper conveyance direction,
The registration lower guide plate is bent in a downstream portion in the paper conveyance direction on the registration roller side and in an upstream portion in the paper conveyance direction from the downstream portion, and the downstream portion The angle formed by the upstream portion with respect to the horizontal direction is larger than the angle formed with respect to the horizontal direction.
Notching the resist lower guide plate so as to transmit light from the optical member, providing a hole ;
The hole is provided across the downstream portion and the upstream portion of the resist lower guide plate in the transport direction of the paper,
The periphery of the hole and the hole, the resist lower guide plate the downstream side of the resist lower guide plate covered with a transparent film material in a portion and the upstream portion was straddle the conveying direction of the sheet of the An image forming apparatus characterized by eliminating the unevenness. 2. The image forming apparatus according to claim 1, wherein an angle formed by the downstream portion of the resist lower guide plate provided with the film material with respect to a horizontal direction is set to 20 ° or more. 3. The image forming apparatus according to claim 1 , wherein a non-adhesive coating layer is provided on the surface of the film material. The image forming apparatus according to claim 3, the image forming apparatus characterized by comprising said non-tacky coating layer as coating layers of polyfluoroethylene. The image forming apparatus according to any one of claims 1 to 4, and pentagonal shape of the hole, or in the transport direction of the paper and the downstream portion and the upstream portion of the resist lower guide plate site to reluctant is along a conveying direction of the sheet, the image forming apparatus characterized by comprising coordinated vertices acute furthest downstream in the conveying direction of the paper.