JP2010173763A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of forming an image under a proper image forming condition corresponding to a kind of recording paper, by discriminating the kind (a thickness) of recording paper. <P>SOLUTION: A first recording paper sensor 31 and a fan 33 are arranged along a carrying passage in the recording paper carrying passage between a carrier roller 26 of a paper feeding part and a timing roller 27. When the recording paper is a thick paper Pa, the contact point of a contactor 31a of the first recording paper sensor becomes ON without largely deflecting even through the air pressure of the fan 33 as indicated by a continuous line in Fig.2, and the recording paper is determined as the thick paper Pa. When the recording paper is a plain paper Pn or a thin paper Pb thinner than the plain paper, the contact point of the contactor 31a of the first recording paper sensor 31 becomes OFF by deflecting through the air pressure of the fan 33 as indicated by a dotted line in the Fig.2, and the recording paper is determined as the plain paper Pn or the thin paper Pb, and the proper image forming condition corresponding to the kind of recording paper can be set. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a facsimile machine, a printer, and a multifunction machine of these.

  In a conventional electrophotographic image forming apparatus, various types of recording papers having different thicknesses can be used. However, in order to prevent poor transfer and poor fixing and create a record with good image quality, the recording paper used is The transfer voltage, the fixing temperature, the process conditions, and the like are changed according to the type (generally plain paper, thick letters, special paper, etc.).

  In order to input information relating to the type of recording paper to the image forming apparatus, it is configured to input from the operation panel of the image forming apparatus or a PC monitor connected to the image forming apparatus before starting the image forming operation. ing. In addition, when inputting information about the type of recording paper, regardless of manual input from the operation panel or the like, after the leading edge of the recording paper contacts the registration roller in the recording paper conveyance path inside the image forming apparatus, When the recording paper is strong, that is, when the thickness of the recording paper is thick, it is determined that the recording paper is a thick letter by utilizing the fact that the conveyance roller idles and does not bend (Patent Document 1) There is a member (Patent Document 2) for determining the type of recording paper by determining the bending strength of the recording paper from the pressing force by providing a member for pressing the recording paper on the conveyance path. There are also proposals for changing the transfer voltage, fixing temperature, process conditions and the like.

JP 2000-75565 A JP-A-6-80273

  However, if the information regarding the type of recording paper is erroneously entered or forgotten in the image forming apparatus, the image will not be formed under an appropriate condition according to the type of recording paper, resulting in an unsatisfactory image. As a result, a quality image is formed. The present invention solves the above-described problems by providing a new configuration for identifying the type of recording paper on the recording paper transport path.

  The present invention solves the above problems, and the invention of claim 1 includes at least a paper feeding unit, an image forming unit, and a conveyance path for conveying recording paper from the paper feeding unit toward the image forming unit. In the image forming apparatus, the transport path includes a pair of transport rollers and a pair of timing rollers, and a first recording paper sensor detects a displacement of the transported recording paper between the transport rollers and the timing roller. And a fan that blows air toward the recording paper to be conveyed, and the first recording paper sensor detects the displacement of the recording paper due to the air blown from the fan and identifies the thickness of the recording paper An image forming apparatus that outputs a signal.

  The blowing force of the air blown from the fan is preferably adjustable according to the thickness of the recording paper to be detected.

  Further, a second recording paper sensor is disposed on the opposite side of the conveying path from the first recording paper sensor across the recording paper to be conveyed, and displacement of the recording paper due to air blown from the fan is detected. A signal for detecting and identifying the thickness of the recording paper may be output.

  According to a fourth aspect of the present invention, there is provided an image forming apparatus including at least a sheet feeding unit, an image forming unit, and a conveyance path for conveying a recording sheet from the sheet feeding unit toward the image forming unit. A conveying roller, a pair of timing rollers, and a first recording sheet sensor that detects a displacement of the recording sheet to be conveyed are disposed between the conveying roller and the timing roller, and the first recording sheet The sensor is an image forming apparatus that detects a displacement of the recording sheet due to the gravity of the recording sheet between the conveying roller and the timing roller, and outputs a signal for identifying the thickness of the recording sheet.

  In addition, a signal for identifying the thickness of the recording paper by detecting a displacement of the recording paper due to the gravity of the recording paper from the side of the conveying guide, further arranging a second recording paper sensor on the conveyance guide side in the conveyance path. May be output.

  The image forming apparatus according to claim 1 or 4, wherein the image forming apparatus includes: a recording sheet conveyance speed based on a signal identifying the thickness of the recording sheet output from the first and / or second recording sheet sensor; Adjustment means for adjusting at least one of the transfer voltage applied to the transfer device, the contact pressure of the pair of conveying rollers, and the fixing temperature of the fixing device may be provided.

  According to the present invention, the first and / or second recording paper sensor arranged in the transport path detects the displacement of the recording paper and outputs a signal for identifying the thickness of the recording paper. In other words, it is possible to set the image forming conditions according to the type of recording paper, and even if the information regarding the type of recording paper is input incorrectly or forgotten, it is always appropriate for the type of recording paper. Image forming conditions can be set, and a high-quality image can be formed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a configuration of a full-color image forming apparatus embodying the present invention (Example 1). FIG. 3 is a diagram for explaining the arrangement positions of first and second recording paper sensors, which are constituent members for identifying the type of recording paper of the image forming apparatus shown in FIG. FIG. 2 is a diagram (part 2) for explaining the arrangement positions of the first and second recording sheet sensors and the fans, which are constituent members for identifying the type of recording sheet of the image forming apparatus shown in FIG. 1, and the conveyance state of the recording sheet. FIG. 2 is a diagram for explaining the configuration of a monochrome image forming apparatus embodying the present invention (Example 2). FIG. 5 is a diagram (No. 1) for explaining an arrangement position of first and second recording paper sensors and a conveyance state of the recording paper that are constituent members for identifying the type of recording paper of the image forming apparatus shown in FIG. FIG. 5 is a diagram (part 2) for explaining the arrangement positions of the first and second recording paper sensors and the conveyance state of the recording paper, which are constituent members for identifying the type of recording paper of the image forming apparatus shown in FIG.

  Hereinafter, embodiments for carrying out the present invention will be described.

  FIG. 1 is a diagram for explaining the configuration of a tandem-type full-color image forming apparatus 10 according to Embodiment 1 of the present invention. Since the tandem-type full-color image forming apparatus itself is a known configuration, only the outline of the configuration is shown. Briefly described.

  In FIG. 1, image forming units 11, 12, 13, and 14 that form images of yellow (Y), magenta (M), cyan (C), and black (K) colors are a driving roller 15 and a driven roller 16. The intermediate transfer belt 17 is arranged in series under an intermediate transfer belt 17 that is an intermediate transfer member laid between the two, and the intermediate transfer belt 17 is fixed in the direction of arrow a by a driving roller 15 driven through a motor and a driving device (not shown). It is configured to move at speed.

  Each of the image forming units 11 to 14 is provided with a photoreceptor, which is an image carrier, a charging device, an exposure device, a developing device, and a cleaning device that cleans transfer residual toner on the photoreceptor. Since the configuration is not the subject of the present invention, the description is omitted here. The image signal processing device 20 receives an image signal output from a scanner (not shown) or an image signal output from a personal computer or the like, and corresponds to the color of the image to be formed in the exposure device of each image forming unit 11-14. The output image signal is output. A paper feeding unit 21 is disposed below the image signal processing device 20.

  Each of the image forming units 11 to 14 is not provided with a transfer device. Instead, the primary transfer rollers 11T, 12T, 13T, and 14T are disposed on the opposite side of the image forming units 11 to 14 with the intermediate transfer belt 17 interposed therebetween. Is arranged.

  Further, a secondary transfer roller 18 is disposed at a position facing the driven roller 16 with the intermediate transfer belt 17 interposed therebetween, and a belt cleaning device 19 is disposed at a position facing the drive roller 15 with the intermediate transfer belt 17 interposed therebetween. ing.

  A fixing device 22 for fixing the toner image transferred onto the recording paper is disposed on the downstream side of the secondary transfer roller 18, and a paper discharge roller 23 and a paper discharge tray 24 are disposed on the downstream side thereof. ing.

  The operation of the full-color image forming apparatus 10 will be briefly described. When the power is turned on, the intermediate transfer belt 17 starts moving at a constant speed in the direction of arrow a. An image forming operation is started, and yellow (Y), magenta (M), cyan (C), and black (K) toner images are formed on the photoreceptors of the image forming units 11 to 14, respectively. . The yellow (Y) toner image is transferred onto the intermediate transfer belt 17 by the operation of the primary transfer roller 11T, and the magenta (M) toner image is superimposed and transferred thereon by the operation of the primary transfer roller 12T. Thereafter, in the same manner, cyan (C) and black (K) toner images are sequentially superimposed and transferred to form a full-color toner image on the intermediate transfer belt 17.

  The recording paper P is fed from the paper feed tray 21a of the paper feed unit 21 at the timing when the full-color toner image formed on the intermediate transfer belt 17 reaches the position of the secondary transfer roller 18, and the secondary transfer is performed. The full-color toner image on the intermediate transfer belt 17 is transferred onto the recording paper P by the operation of the secondary transfer roller 18 which is an apparatus. Thereafter, the recording paper P is conveyed to the fixing device 22, and the toner image on the recording paper P is fixed, and is discharged to the paper discharge tray 24 through the paper discharge roller 23.

  Although transfer residual toner remains on the intermediate transfer belt 17, it interferes with the next image formation. Therefore, the surface of the intermediate transfer belt 17 is cleaned by the belt cleaning device 19 and the transfer residual toner is removed.

  The paper feed unit 21 shows a state in which the paper feed tray 21a is attached to one paper feed port, and the other paper feed ports and paper feed trays are not shown.

  Recording paper P is stored in the paper supply tray 21a. The paper supply roller 25 is brought into frictional contact with the uppermost recording paper P of the stored recording paper, and the uppermost recording paper P is rotated by the rotation of the paper supply roller 25. Is configured to be fed.

  The recording paper P fed from the paper feed roller 25 is transported by the transport roller 26, transported to the timing roller 27 through the transport path, and temporarily stops. The timing roller 27 starts rotating at the timing when the full-color toner image formed on the intermediate transfer belt 17 reaches the position of the secondary transfer roller 18, and as described above, the full-color toner image on the intermediate transfer belt 17 is formed. Transferred onto recording paper P.

  Next, a configuration for identifying the type of recording paper will be described. Here, the type of recording paper refers to the thickness of the recording paper, and there are three types of recording paper: plain paper, thin letters, and thick letters.

  In FIG. 1, a first recording paper sensor 31 and a fan 33 are arranged in the recording paper conveyance path between the conveyance roller 26 and the timing roller 27 of the paper supply unit 21.

  2 and 3 are diagrams for explaining the arrangement position of the recording paper sensor 31 and the fan 33, which are constituent members for identifying the type of the recording paper P (the thickness of the recording paper), and the conveyance state of the recording paper P. FIG. 2 shows a conveying state of thick letters with a thick recording paper P, and FIG. 3 shows a conveying state of plain paper and thin letters with a thin recording paper P.

  As shown in FIG. 2, a first recording paper sensor 31 and a fan 33 are arranged along the conveyance path, and a contact 31 a that contacts the surface of the recording paper P is provided on the first recording paper sensor 31. The contact 31a is urged toward the recording paper P by a spring member (not shown).

  The first recording paper sensor 31 is a switch-type sensor that is pressed when the contact 31a comes into contact with the conveyed recording paper P, and the contact is turned on. The biasing force of the spring member is adjusted so that the contact is turned on when the contact 31a comes into contact with the surface of the recording paper P due to the strength of.

  The fan 33 blows air toward the recording paper P to be transported, and is disposed upstream of the contact 31a in the recording paper transport direction. In this case, the air blowing force is adjusted so that the recording paper P bends in a direction away from the contact 31a by the blown air.

  In the above configuration, when the recording paper P is a thick letter Pa, as shown by a solid line in FIG. 2, the first sheet is not bent or slightly bent by the air pressure of the fan 33. The contact of the contact 31a of the recording paper sensor 31 is turned on, and it is determined that the recording paper P is a thick letter Pa.

  When the recording paper P is a normal paper Pn having a normal thickness or a thin letter Pb thinner than the normal paper, the first recording paper is bent by the air pressure of the fan 33 as shown by the dotted line in FIG. The contact of the contact 31a of the sensor 31 is turned off, and it is determined that the recording paper P is a plain paper Pn or a thin letter Pb.

  Further, when it is necessary to discriminate between the normal paper Pn having a normal thickness and the thin letter Pb having a thickness smaller than that, the second recording paper sensor is placed on the opposite side across the recording paper P to be conveyed. 32, and only the recording paper Pb thinner than the plain paper Pn is configured to come into contact with the contact 32a of the second recording paper sensor 32.

  As a result, if the recording paper P is plain paper Pn, as shown by the one-dot chain line in FIG. 3, the fan 33 is bent by the air pressure, and the contact of the contact 31a of the first recording paper sensor 31 is turned off. The contact of the contact 32a of the second recording paper sensor 32 is also maintained in the OFF state, and it is determined that the recording paper P is plain paper Pn. If the recording paper P is a thin letter Pb, as shown by a two-dot chain line in FIG. 3, the recording paper P is greatly bent by the air pressure of the fan 33, and the contact of the contact 31 a of the first recording paper sensor 31 is turned OFF. Since the deflection of the recording paper P is large, the contact of the contact 32a of the second recording paper sensor 32 is turned on, and it is determined that the recording paper P is a thin letter Pb.

  FIG. 4 is a diagram for explaining the configuration of the image forming apparatus according to the second embodiment in which the present invention is implemented, and is a monochrome image forming apparatus 40 provided with only one image forming unit. Since the monochrome image forming apparatus itself has a known configuration, only the outline of the configuration will be briefly described.

  The image forming apparatus 40 has a configuration in which the recording paper P is conveyed in the horizontal direction, and the recording paper P can be bent downward by gravity on the conveyance path. The image forming unit 41 includes a photoconductor, a charging device, and an exposure. An apparatus, a developing device, and a cleaning device for cleaning the transfer residual toner on the photosensitive member are disposed. Since the configuration is not the subject of the present invention, the description is omitted here.

  The image forming apparatus 40 includes an image signal processing device 42 and a paper feed unit 43, and a fixing device 44, a paper discharge roller 45, and a paper discharge tray 46 on the downstream side of the image forming unit 41 in the recording paper conveyance direction. Is arranged.

  Recording paper P is stored in the paper supply unit 43, and the paper supply roller 47 comes into frictional contact with the uppermost recording paper P of the stored recording paper P, and the uppermost recording paper is rotated by the rotation of the paper supply roller 47. P is configured to be fed.

  The operation of the image forming apparatus 40 will be briefly described. An image signal output from a scanner (not shown) or an image signal output from a personal computer or the like is input to the image signal processing device 42, and after image editing processing, the processed image signal is output from the image forming unit 41. Output to the exposure apparatus. The photoconductor 41a of the image forming unit 41 is charged to a predetermined potential by a charging device, and an image signal is projected from the exposure device onto the charged photoconductor 41a to form an image latent image. The latent image on the photoconductor 41a is developed with toner to form a toner image.

  The recording paper P fed from the paper feed roller 47 is transported by the transport roller 48, transported to the timing roller 49 through the transport path, and temporarily stops. The timing roller 49 starts rotating at the timing when the toner image formed on the photoconductor 41a of the image forming unit 41 reaches the position of the transfer roller 50, and the conveyance of the recording paper P is started. The toner image formed on the recording paper P is transferred onto the recording paper P by the action of the transfer roller 50. Thereafter, the recording paper P onto which the toner image has been transferred is subjected to fixing processing by the fixing device 44 and is discharged to the paper discharge tray 46 via the paper discharge roller 45.

  Next, a configuration for identifying the type of recording paper will be described. Here, the type of recording paper refers to the thickness of the recording paper, and there are three types of recording paper: plain paper, thin letters, and thick letters.

  In FIG. 4, a first recording paper sensor 51 is disposed above the conveyance path along the recording paper conveyance path between the conveyance roller 48 and the timing roller 49 of the paper feed unit 43. A recording paper guide 52 is disposed on the side. FIG. 5 is a diagram for explaining the arrangement position of the recording paper sensor 51, which is a constituent member for identifying the type of recording paper P (recording paper thickness), and the conveyance state of the recording paper P. The first recording paper sensor 51 is provided with a contact 51 a that contacts the surface of the recording paper P.

  The contact 51a of the first recording paper sensor 51 is biased by a spring member (not shown). When the recording paper P is a thick letter Pa, the contact is turned on by the strength of the recording paper P, and the recording paper P In the case of plain paper Pn or thin letter Pb, the force of the spring member is adjusted so that the contact 51a does not contact the recording paper P and the contact is turned off.

  The recording sheet P is fed by the sheet feeding roller 47 of the sheet feeding unit 43 and is conveyed by the conveying roller 48, and the leading end of the recording sheet P comes into contact with the nip portion of the timing roller 49, so When the recording paper P is a thick letter Pa, the intermediate portion of the recording paper P (intermediate portion of the timing roller 49 and the transporting roller 48), as shown by the solid line in FIG. ) Slightly bends downward due to gravity, but due to the strength of the thick letter Pa, the contact 51a of the first recording paper sensor 51 is pressed upward to turn the contact ON, and the recording paper P is thick. It can be identified that the letter is Pa.

  When the recording paper P is plain paper Pn or thin letter Pb, as shown by the dotted line in FIG. 5, there is no stiffness, so the middle part (the middle part of the timing roller 49 and the transport roller 48) hangs down due to gravity. The contact of the contact 51a of the first recording paper sensor 51 is not turned ON. Thereby, it can be identified that the type of the recording paper is plain paper Pn or thin letter Pb.

  Further, when it is necessary to identify the type of recording paper as plain paper Pn and thin letter Pb, a second recording paper sensor 53 having a contact 53a is provided on the recording paper guide 52 below the conveyance path. Good.

  When the leading end of the recording paper P comes into contact with the nip portion of the timing roller 49 and the rear portion (or the rear end) of the recording paper P is sandwiched between the conveying rollers 48, in the case of plain paper Pn or thin letter Pb, FIG. As shown in FIG. 6, an intermediate portion of the recording paper P (an intermediate portion between the timing roller 49 and the conveyance roller 48) hangs down due to gravity. At this time, when the recording paper P is separated from the contact 51a of the recording paper sensor 51 and the contact of the contact 51a is not turned ON, and the contact of the contact 53a of the second recording paper sensor 53 is not turned ON, It is identified as plain paper Pn.

  Then, as shown in FIG. 6, the intermediate portion of the recording paper P (intermediate portion of the timing roller 49 and the conveying roller 48) hangs down to the recording paper guide 52 by gravity, and the contact of the contact 51a of the recording paper sensor 51 is ON. In addition, when the contact of the contact 53a of the second recording paper sensor 53 is turned ON, it can be determined that the letter Pb is thin.

  In the image forming apparatus provided with the first and / or second recording paper sensor of the present invention, recording is performed based on a signal for identifying the thickness of the recording paper output from the first and / or second recording paper sensor. By providing an adjusting means for adjusting any one or more of the paper conveyance speed, the transfer voltage applied to the transfer device, the contact pressure of the pair of conveyance rollers, and the fixing temperature of the fixing device, an appropriate image formation according to the type of the recording paper is provided. An image can be formed under certain conditions.

  Provided is an image forming apparatus having a configuration for identifying the type of recording paper to be used and capable of forming an image under appropriate image forming conditions according to the type of recording paper.

DESCRIPTION OF SYMBOLS 10 Full color image forming apparatus 11, 12, 13, 14 Image forming unit 11T, 12T, 13T, 14T Primary transfer roller 15 Drive roller 16 Driven roller 17 Intermediate transfer belt 18 Secondary transfer roller 19 Belt cleaning device 20 Image signal processing device 21 Paper feed unit 22 Fixing device 23 Paper discharge roller 24 Paper discharge tray 25 Paper feed roller 26 Transport roller 27 Timing roller 31 Recording paper sensor 31a Contact 32 Second recording paper sensor 32a Contact 33 Fan 40 Image forming device 41 Image forming device 41 Unit 41a Photoconductor 42 Image signal processing device 43 Paper feed unit 44 Fixing device 45 Paper discharge roller 46 Paper discharge tray 47 Paper feed roller 48 Transport roller 49 Timing roller 50 Transfer roller 51 Recording paper sensor 51a Contact 52 Recording paper guide 53 2 records Paper sensor 53a Contact

Claims (6)

In an image forming apparatus comprising at least a paper feeding unit, an image forming unit, and a conveyance path for conveying recording paper from the paper feeding unit toward the image forming unit,
The conveyance path includes a conveyance roller and a timing roller, and a first recording sheet sensor that detects a displacement of the conveyed recording sheet is disposed between the conveyance roller and the timing roller, and is directed to the conveyed recording sheet. A fan that blows air
The image forming apparatus, wherein the first recording paper sensor detects a displacement of the recording paper due to air blown from the fan, and outputs a signal for identifying the thickness of the recording paper. The image forming apparatus according to claim 1, wherein a blowing force of air blown from the fan can be adjusted according to a thickness of the recording paper to be detected. In the transport path, a second recording paper sensor is arranged on the opposite side of the first recording paper sensor across the recording paper to be transported, and the displacement of the recording paper due to the air blown from the fan is detected. 2. The image forming apparatus according to claim 1, wherein a signal for identifying the thickness of the recording paper into three types is output. In an image forming apparatus comprising at least a paper feeding unit, an image forming unit, and a conveyance path for conveying recording paper from the paper feeding unit toward the image forming unit,
In the conveyance path, a pair of conveyance rollers, a pair of timing rollers, and a first recording sheet sensor that detects a displacement of the conveyance sheet and the conveyance sheet are disposed between the conveyance rollers and the timing roller. ,
The first recording paper sensor detects a displacement of the recording paper due to the gravity of the recording paper between the conveying roller and the timing roller, and outputs a signal for identifying the thickness of the recording paper. Forming equipment. In the transport path, a second recording paper sensor is further arranged on the transport guide side, and the displacement of the recording paper due to the gravity of the recording paper is detected from the transport guide side to identify the recording paper thickness into three types. The image forming apparatus according to claim 4, wherein a signal is output. The image forming apparatus includes a recording sheet conveyance speed, a transfer voltage applied to the transfer apparatus, and a pair of conveyance rollers based on a signal identifying the thickness of the recording sheet output from the first and / or second recording sheet sensor. 5. The image forming apparatus according to claim 1, further comprising an adjusting unit that adjusts at least one of the contact pressure and the fixing temperature of the fixing device.

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