JP2008201512A - Paper conveying device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce erroneous detection when paper information is detected and to certainly determine double feeding by determining double feeding of paper from the first paper even when a paper storage means is switched. <P>SOLUTION: Two paper information detection means 200 of the paper conveying device are provided, and a double feeding determination means 310 performs determination of the double feeding based on the input paper information regarding the first paper of the paper feeding tray 21. When the first paper is not double feeding, the means 310 performs determination of double feeding on and after that based on the paper information of the first paper obtained from the paper information detection means 200. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet conveying device and an image forming apparatus, and in particular, a plurality of sheet storing units for storing sheets, a sheet feeding unit for feeding sheets one by one from each sheet storing unit, and a conveyance for conveying a sheet. The present invention relates to a sheet conveying apparatus including a path and an image forming apparatus using the sheet conveying apparatus.

  In recent years, image forming apparatuses such as copiers and printers have started to enter the printing industry as speed increases. Even when printing business documents in the office, reducing downtime due to jams is an important issue, but mixing of unprinted paper due to multi-feed during mass printing causes a great deal of damage including checking.

  For this reason, the following technique has been proposed in order to realize a high-speed document printing stamp by preventing double feeding in the image forming apparatus.

  In Patent Document 1, the automatic detection function of the paper type including at least the paper thickness used for variable setting of the fixing temperature can be provided, and the detection result can be effectively and reliably used. In order to eliminate waste of energy and energy, at the timing prior to the paper feed command, the leading edge of one sheet is fed by a predetermined amount from the paper storage unit by the separation paper feeding unit, and the paper type of the paper is detected by the paper type detection unit. The paper type information is acquired before receiving the paper feed command, and the paper type information is effectively and reliably used for the image forming process of the image forming means before receiving the paper feed command. It is possible to eliminate the waste of time and energy in the image forming process.

In Patent Document 2, there is a document with strip-like vertical stripes and printing, and even if the strip-like vertical stripes and printing are located at a position opposite to the double feed detection range, a setting is made so that double feed detection can be avoided. In order to perform multifeed detection without any false detections, the main scanning direction of the document can be moved between the front plate and the rear plate with a light emitting sensor mounted and a light receiving sensor mounted on each axis. It is held in a movable manner. A moving body is fixed to each wire wound between a plurality of arranged pulleys, and both moving bodies are described so as to be movable in the same direction in conjunction with each other.
JP 2004-277057 A JP 2003-146482 A

  By the way, when a large amount of printing is performed in an image forming apparatus, it is common to feed paper from a plurality of paper feed trays in order to improve the efficiency of paper supply work. However, conventionally, it is common to detect the double feed by comparing the paper information of the preceding paper and the paper information of the current paper, and control for detecting the double feed for the first paper. Was not implemented. For this reason, when the paper feed is switched to another paper feed tray, there is a problem that it is not possible to detect double feed for the first sheet from the paper feed tray.

  Also, when different size papers (for example, A3 and A4) are stored in the paper feed tray for mixed size printing, or papers of different paper types (for example, plain paper and coated paper) are fed. Multi-feed could not be detected when printing on a tray.

  Conventionally, since only one detection means for detecting paper information is generally provided at the transport center of the paper transport path, fiber irregularities and foreign matter that rarely occur during the paper-making process. If the location where the transmittance of the paper has changed significantly compared to other locations due to mixing, etc., and the location where the paper information is detected match, it is possible to double-feed even though there is only one paper. Sometimes it was detected.

  The present invention has been made in view of the above-described problems, and reduces erroneous detection when detecting paper information, and allows multiple paper feeding from the first paper even when the paper storage means is switched. An object of the present invention is to provide a sheet conveying apparatus capable of reliably determining double feeding and an image forming apparatus using the same.

  According to a first aspect of the present invention, there is provided a paper transport apparatus comprising a plurality of paper storage means for storing paper, a paper feed means for feeding paper one by one from each paper storage means, and a transport path for transporting the paper. A sheet information setting unit that sets sheet information of each sheet corresponding to the sheet storage unit, a sheet information storage unit that stores sheet information of each sheet corresponding to the sheet storage unit, and a sheet of the sheet to be conveyed Paper information detection means for detecting information on the transport path, paper feed information from the paper information storage means, and paper feed information from the paper information detection means to detect double feed of paper And storage control means for rewriting the paper information in the paper information storage means, the storage control means from the paper information setting means when the first paper from the paper storage means is conveyed Paper information is stored in the paper information storage means, and when the multi-feed determination means determines that the first sheet is not multi-feed, the paper information from the paper information detection means is stored in the paper information storage means. A sheet conveying apparatus characterized by writing.

  According to a second aspect of the present invention, in the paper conveying apparatus according to the first aspect, the paper information detecting means includes a light emitting portion and a light receiving portion that are disposed with the conveyed paper interposed therebetween, and at least two pieces of information detection. The means is characterized in that it is arranged at a predetermined distance from the conveyance center perpendicular to the conveyance direction.

  According to a third aspect of the present invention, in the paper conveying apparatus according to the first or second aspect, the paper information is light transmittance.

  According to a fourth aspect of the present invention, in the paper conveying apparatus according to any one of the first to third aspects, the light emitting portion of the paper information detecting means includes a light amount setting means for making the light emission amount variable.

  According to a fifth aspect of the present invention, in the paper conveying apparatus according to any one of the first to fourth aspects, the paper information detecting means is configured such that at least two light emitting units emit light with an equivalent light emission amount. The sheet information is obtained from the average value of the output values output from the light receiving unit.

  According to a sixth aspect of the present invention, in the paper conveyance device according to any one of the first to fifth aspects, the light emission amount of the light emitting unit and the paper information set by the paper information setting unit are determined in accordance with the type of the paper. It is characterized by being.

  According to a seventh aspect of the present invention, in the paper conveying apparatus according to any one of the first to fifth aspects, the light emission amount of the light emitting unit and the paper information set by the paper information setting means are paper type information input from the outside. It is characterized by being set corresponding to

  According to an eighth aspect of the present invention, in the paper conveyance device according to any one of the second to seventh aspects, the paper information set by the paper information setting means and stored in the paper information storage means is detected by the paper information detection means. When the paper information of the original paper to be conveyed is significantly different from the paper information of the first paper to be conveyed, a warning means for issuing a warning to alert the outside whether the set paper information is correct without starting the recording operation is provided.

  According to a ninth aspect of the present invention, in the paper conveying apparatus according to any one of the first to seventh aspects, the paper information set by the paper information setting means and stored in the paper information storage means is detected by the paper information detection means. If the paper information is significantly different from the original paper information to be conveyed, the light emission means emits light with a predetermined light emission amount, and paper information is detected again.

  According to a tenth aspect of the present invention, in the paper conveying apparatus according to any one of the first to ninth aspects, the paper information detecting means also serves as a jam detecting means for outputting a jam signal when no paper is detected at a predetermined time. Features.

  According to an eleventh aspect of the present invention, there is provided an image forming apparatus comprising the paper conveying apparatus according to any one of the first to tenth aspects and an image forming means for forming an image.

  According to a twelfth aspect of the present invention, in the image forming apparatus according to the eleventh aspect, the image forming apparatus is an electrophotographic copying machine.

  According to a thirteenth aspect of the present invention, in the image forming apparatus according to the eleventh aspect, the image forming apparatus is a laser beam printer.

  According to the paper conveying device and the image forming apparatus according to the present invention, since a plurality of paper information detecting means are provided, it is possible to reduce erroneous detection when detecting paper information and to use paper sheets used by the paper information setting means. Since the information is stored in the paper information storage means and this paper information is used for double feed detection, even when the paper storage means is switched, it is possible to detect double feed of paper from the first sheet. There is an effect that it is possible to prevent a decrease in printing efficiency due to oversight.

  Embodiments as the best mode for carrying out the present invention will be described below with reference to the drawings.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus includes an image forming unit 1 that forms an image, a paper feeding unit 2 that is disposed below the image forming unit 1 and supplies paper, and an illumination light that is disposed above the image forming unit 1 and irradiates a document. The reading unit 3 that reads an image and the automatic document feeder 100 that is arranged above the reading unit 3 and automatically supplies a document are provided.

  The image forming unit 1 is disposed substantially at the center of the image forming apparatus. The image forming unit 1 includes an image forming unit 6. A drum-shaped photoconductor 61 is disposed in the image forming unit 6. Around the photoconductor 61, a charging unit 62 that charges the surface of the photoconductor 61, and an exposure that irradiates the surface of the photoconductor 61 with laser light. 7, a developing unit 63 that visualizes an electrostatic latent image formed on the surface of the photoconductor 61, and a cleaning unit 64 that removes and collects toner remaining on the surface of the photoconductor 61 are disposed.

  In addition, the image forming unit 1 applies heat and pressure to the transfer unit 51 that transfers the toner image formed on the photoconductor 61 to a sheet, and the toner on the sheet from which the toner image is obtained passes between a pair of rollers. Accordingly, fixing units 52 for fixing the toner image are arranged. The sheet that has passed through the fixing unit 52 is discharged to the discharge storage unit 4 by the discharge roller 53.

  The paper feed unit 2 is provided with a plurality of paper feed trays 21a, 21b, 21c, 21d, which are four paper storage means in this example, and each of the paper feed trays 21a, 21b, 21c, 21d is the same. Large paper is stored.

  On the paper feed trays 21a, 21b, 21c, and 21d, the bottom plates 24a, 24b, 24c, and 24d that are rotatably supported are raised, and the paper that is disposed at the uppermost position is picked up by the pickup rollers 25a, 25b, 25c, and 25d. Is pushed up to a position where can contact. Then, by the rotation of the designated paper feed roller 26, the uppermost sheet of the designated paper feed tray is sent out from the paper feed tray 21 and conveyed to the registration roller 23. The registration roller 23 is controlled so as to start rotation at a timing so that the conveyance of the paper is temporarily stopped and the positional relationship between the toner image on the surface of the photoreceptor 61 and the leading edge of the paper becomes a predetermined position.

  A reading unit 3 for reading a document is disposed above the image forming unit 1, and a paper discharge storage unit 4 is formed on the side of the image forming unit 1, so that a sheet on which an image is formed is stored. Stacked.

  In the reading unit 3, in order to perform reading scanning of the document placed on the contact glass 31, the reading traveling bodies 32 and 33 including the document illumination light source and the mirror reciprocate. Image information scanned by the reading traveling bodies 32 and 33 is read as an image signal into the CCD image pickup device 35 installed behind the lens 34. The read image signal is digitized and image processed by an image processing unit (not shown).

  In the image forming unit 1, 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 unit 7 based on the image signal processed by the image processing unit. The optical signal from the LD reaches the photosensitive member 61 via a known polygon mirror or lens. An automatic document feeder 100 that automatically feeds a document is attached above the reading unit 3.

  At the time of double-sided printing, the paper is branched by the branching claw 91, the paper is reversed by the reversing double-sided portion 9 and conveyed to the registration roller 23, the paper skew is corrected by the registration roller 23, and the back side image forming operation is performed.

  As described above, the image forming apparatus according to the present embodiment exchanges image information of a document with a remote place by a control unit (not shown) in addition to a function as a so-called digital copying machine that reads a document and digitizes it and copies it onto a sheet. This is a multifunction image forming apparatus having a facsimile function and a so-called printer function for printing image information handled by a computer on a sheet. The setting as the copying machine is performed by an operation unit (not shown) that can be arbitrarily set by an operator. Further, all images formed by any function are discharged to the paper discharge storage unit 4.

  When the paper is branched by the branching claw 91 and reversed via the reverse double-sided portion 9 and discharged from the paper discharge roller 53 via the reverse paper discharge roller 54, the paper stacked in the paper discharge storage portion 4 is The image side is the bottom side, and even if the document, which is handled by copying, facsimile, and printer, is processed from the first page, the first page is the top when it is taken out from the paper discharge storage unit 4 It is freed from work such as aligning pages again.

  Next, a sheet conveying device of the image forming apparatus according to the embodiment will be described. FIG. 2 is a schematic diagram showing the structure of the paper transport device according to the embodiment, FIG. 3 is a schematic diagram of the paper transport device, (a) is a plan view, and (b) is a front view.

  In this example, a sheet information detecting unit 200 is disposed in the sheet conveying apparatus. As shown in FIG. 2, the paper information detection unit 200 is disposed upstream of the paper feeding unit 2 and downstream of the registration roller 23. In the figure, reference numeral 27 denotes a conveyance roller. The paper information detection unit 200 includes a light emitting element 210 that is a light emitting unit and a light receiving element 220 that is a light receiving unit. The light emitting element 210 and the light receiving element 220 are arranged so as to sandwich the sheet 20 to be conveyed.

  In this example, the paper information detection means 200 is disposed in the vicinity of the transport roller 27 where the behavior of the transported paper 20 is stable. In addition, it is desirable to detect double feeding before the start of image formation, and in this embodiment, it is arranged upstream of the conveyance path.

  In this example, two paper information detection means 200 are provided, and the two paper information detection means 200a and 200b are arranged on a straight line perpendicular to the transport direction by a fixed distance L across the transport center O of the paper 20. They are placed apart. The distance L from the transport center is a distance at which the smallest usable size paper can be detected.

  In this example, the light emission amounts of the two light emitting elements are made equal to each other, and the probability of erroneous detection can be reduced by detecting the paper information from the average value of the outputs of the light receiving units. In this example, they are arranged on the same straight line perpendicular to the transport direction. However, by not arranging them on the same straight line, misdetection can be reduced by disposing the paper at a position shifted from the grid. Can do.

  Next, control of the sheet conveying apparatus according to this example will be described. FIG. 4 is a block diagram illustrating a control unit of the sheet conveying apparatus.

As shown in FIG. 4, the control unit 300 of the paper transport apparatus receives paper information from the paper information detection means 200, and detects a double feed of the paper 20, and a user feeds each of the paper feeds. Paper information setting means 320 for setting the paper information of each paper corresponding to the trays 21a, 21b, 21c, 21d, and corresponding to each paper feed tray 21a, 21b, 21c, 21d based on the setting of the paper information setting means 320 A sheet information storage unit 330 that stores sheet information of each sheet, a storage control unit 340 that performs rewrite control of the sheet information stored in the sheet information storage unit 330, a warning unit 350 that generates a warning when a double feed is detected, Light amount setting means 360 for setting the light emission amount of the light emitting element 210 of the paper information detecting means 200.

  The multi-feed determination unit 310 determines multi-feed of paper based on the paper information stored in the paper information storage unit 330 and the paper information detected by the paper information detection unit 200. That is, the multi-feed determination unit 310 compares the transmittance obtained from the amount of light received by the light receiving element 220 with the transmittance stored in the sheet information storage unit 330, so that one sheet has passed through the sheet information detection unit 200. It is determined whether it was a double feed or two sheets.

  The paper information setting unit 320 sets information on the paper transmittance as an initial value of the paper information, for example, by designating the type of paper by user operation. In this example, the designated sheet information is the transmittance when there is one sheet and two sheets. In the paper information setting unit 320, the light emission amount of the light emitting element 210 is set for each paper type.

  Table 1 shows an example of the paper information setting. In this example, there are three types of paper: plain paper (45K), second original drawing, and OHP paper, and the light emission amount is designated as the transmittance.

  In the example shown in Table 1, the paper type is classified into three types: plain paper, second original drawing, and OHP paper. However, the area grouped as plain paper can be subdivided according to the paper thickness, and more accurate weight can be obtained. Sending judgment can be made possible.

  In the example shown in Table 1, the light emission amount is a relative value with the light emission amount with respect to the second original drawing being 1. In addition, it is known from experiments and the like that in the double feed state in which two sheets are overlapped, the transmittance is about half in the paper type, and it can be set as a threshold for determining the double feed. Note that the transparencies of OHP sheets are remarkably high, and it is necessary to set a separate threshold for determining multifeed.

  The sheet information storage unit 330 stores the light emission amount of the light emitting element 210 based on the control of the storage control unit 340. The light amount setting unit 360 causes the light emitting element 210 to emit light based on the light emission amount stored in the paper information storage unit 330. Further, the multi-feed determination unit 310 determines multi-feed based on the transmissivity that is the paper information stored in the paper information storage unit 330 and the detection value of the paper information detection unit 200.

  The light amount setting unit 360 adjusts the light emission amount of the light emitting element 210 within a predetermined range. As shown in Table 1, since the transmittance value varies significantly depending on the paper, the paper types are roughly classified into three categories. For this reason, the light quantity setting means 360 can adjust the light emission amount of the light emitting element 210, and can improve the detection accuracy within the same classification. In addition, if the light emitting element 210 emits a large amount of light with respect to a sheet with high transmittance, a problem such as overflow of the output of the paper information setting unit 320 may occur. Therefore, a light amount setting unit 360 for adjusting the light emission amount is necessary. It may become. Further, by adjusting the light emitting element 210 so that the output value of the light receiving element 220 is within a predetermined range, it is possible to cope with all the paper types used by the user.

  The storage control unit 340 controls the storage contents of the paper information storage unit 330. That is, the storage control means 340 is the paper information of the paper designated by the paper information setting means 320 when each paper feed tray 21a, 21b, 21c, 21d is designated and the first paper passes. The transmittance is written in the paper information storage unit 330.

  Based on this value, the paper information setting means 320, for the first paper from each of the paper feed trays 21a, 21b, 21c, 21d, the paper information set by the user with the paper information setting means 320 and the paper information. The paper information detected by the detecting means 200 is compared, and double feeding of paper is determined.

  The storage control unit 340 then detects the sheet information detection unit 200 when the first sheet is not double-fed, that is, when the sheet is normally conveyed after the double-feed determination unit 310 determines that the first sheet is double-fed. The transmittance determined based on the detected value is newly stored in the sheet information storage unit 330 as sheet information.

Action of Multifeed Determination Unit 310 The multifeed determination unit 310 performs the above-described multifeed determination, and also detects the sheet information specified by the user from the sheet information setting unit 320 and one sheet detected by the sheet information detection unit 200. If the eye paper information is significantly different, the warning means 350 displays a message for alerting the user without starting the recording operation. Thereby, it is possible to prevent erroneous detection of double feed due to an erroneous operation by the user.

  As the paper information setting unit 320 and the warning unit 350, the following liquid crystal display type touch panel can be used. FIG. 5 is a schematic diagram showing an external appearance of an operation panel used as paper information setting means, and FIG. 6 is a schematic view showing an external appearance of an operation panel used as warning means.

  On the operation panel 410, a liquid crystal touch panel unit 420, a numeric keypad unit 430, and a start button 440 are arranged. In this example, the roles of the paper information setting unit 320 and the warning unit 350 are executed by changing the display on the liquid crystal touch panel unit 420.

  When the operation panel 410 is used as the paper information setting unit 320, a paper type selection screen is displayed on the liquid crystal touch panel unit 420 as shown in FIG. When the operation panel 410 is used as the warning unit 350, a warning screen is displayed on the liquid crystal touch panel unit 420 as shown in FIG. Note that the warning means may be provided with a dedicated display unit instead of performing display on the operation panel 410, or may be provided with means for giving a warning by voice.

  In addition to the double feed detection, the multi-feed determination unit 310 performs conveyance in which the paper information set by the paper information setting unit 320 and stored as the initial value in the paper information storage unit 330 is detected by the paper information detection unit. When the paper information is significantly different from the first paper information to be printed, the paper information detection is performed again with another light emission amount prepared for each paper type, thereby continuing the printing operation without bothering the user. Control can be performed.

  Further, the multi-feed determining unit 310 can output a jam signal when the sheet information detecting unit 200 does not detect a sheet within a predetermined time. In this way, the detection of the paper information of the paper information detection means 200 can be used for both the double feed judgment and the jam detection.

  Next, the operation of the sheet conveying apparatus according to the embodiment will be described. FIG. 7 is a flowchart illustrating the operation of the sheet conveying apparatus according to the embodiment. When printing, the operator first designates the paper feed tray 21 to be used (ST1) and inputs paper information (ST2). The paper information is input by designating the paper type from the operation panel 410.

  Then, the storage control means 340 sets the paper information and the amount of emitted light as the initial information in the paper information storage means 330 (ST3). As a result, the multi-feed determination unit 310 sets the first sheet from the set paper feed tray 21 to the sheet information stored in the sheet information storage unit 330 and the sheet information obtained by the sheet information detection unit 200. Will be compared. The light amount setting unit 360 emits light from the light emitting element 210 with the set light amount.

  When the start button 440 is pressed, the first sheet is transported from the designated paper feed tray 21 (ST4), and when the transmissivity is obtained as the sheet information by the sheet information detecting unit 200, the double feed determining unit 310 is obtained. Compares the paper information stored in the paper information storage means 330 with the paper information obtained by the paper information detection means 200, and the conveyed paper is one sheet or two sheets that have been double-fed. Is determined (ST6).

  When the sheet is normally conveyed, the storage control unit 340 stores the sheet information from the sheet information detection unit 200 in place of the sheet information from the sheet information setting unit 320 stored in the sheet information storage unit 330. (ST7), the multi-feed determining unit 310 subsequently performs multi-feed determination based on the newly stored paper information (ST8).

  On the other hand, when the double feed determination unit 310 determines the double feed, the difference between the paper information stored in the paper information storage unit 330 and the paper information obtained by the paper information detection unit 200 is a predetermined value. If it is smaller, it is determined that double feeding is performed, and a specified double feeding process such as issuing an alarm or stopping the sheet conveying device is performed. The operator receives this process and performs a predetermined operation such as inspection of the transport device. Further, when the difference is larger than the predetermined value, an abnormality warning is issued and the warning shown in FIG. 7 is issued on the liquid crystal touch panel 420 of the operation panel 410. The operator receives this warning and confirms the setting again.

  As the image forming apparatus, there are an electrophotographic copying machine, a laser beam printer, a facsimile machine, and the like, and it is possible to detect these double feeds with high accuracy.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment. FIG. 3 is a schematic diagram illustrating a structure of a paper transport device. 2A and 2B are schematic views of a sheet conveying device, where FIG. 1A is a plan view and FIG. 1B is a front view. Block diagram showing the control unit of the paper transport device It is a schematic diagram showing an appearance of an operation panel used as a paper information setting unit. It is a schematic diagram which shows the external appearance of the operation panel used privately as a warning means. 6 is a flowchart illustrating an operation of the sheet conveying device according to the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image formation part 2 Paper feed part 3 Reading part 4 Paper discharge storage part 6 Image creation part 7 Exposure part 9 Reverse both sides part 20 Paper 21 Paper feed tray 21a, 21b, 21c, 21d Paper feed tray 23 Registration roller 24a, 24b, 24c, 24d Bottom plates 25a, 25b, 25c, 25d Pickup roller 26 Paper feed roller 27 Transport roller 31 Contact glass 32, 33 Reading traveling body 34 Lens 35 CCD image sensor 51 Transfer unit 52 Fixing unit 53 Paper discharge roller 54 Reverse paper discharge roller 61 Photosensitive member 62 Charging unit 63 Developing unit 64 Cleaning unit 91 Branch claw 100 Automatic document feeder 200 Paper information detecting means 200a, 200b Paper information detecting means 210 Light emitting element 220 Light receiving element 300 Control unit 310 Multi feed determining means 320 Paper information setting Means 330 Paper information storage means 340 Storage control means 350 WARNING means 360 light amount setting means 410 the operation panel 420 liquid crystal touch panel 430 ten-key section 440 start button

Claims (14)

Corresponding to the paper storage means in a paper transport device comprising a plurality of paper storage means for storing paper, a paper feed means for feeding paper one by one from each paper storage means, and a transport path for transporting the paper Paper information setting means for setting paper information of each paper to be
Paper information storage means for storing paper information of each paper corresponding to the paper storage means;
Paper information detection means for detecting paper information of the paper to be transported in the transport path;
A double feed judging means for comparing the paper information from the paper information storage means and the paper information from the paper information detecting means to detect double feed of paper;
Storage control means for rewriting the paper information of the paper information storage means,
The storage control means
When the first sheet from the sheet storage means is transported, the sheet information from the sheet information setting means is stored in the sheet information storage means,
A paper conveying apparatus, wherein when the multi-feed determining unit determines that the first sheet is not a multi-feed, the paper information from the paper information detecting unit is written in the paper information storing unit. The paper information detection means includes a light emitting unit arranged with the conveyed paper interposed therebetween, and a light receiving unit,
2. The paper conveying apparatus according to claim 1, wherein the at least two information detecting means are arranged at a predetermined distance with the conveyance center perpendicular to the paper conveyance direction.   3. The paper conveying apparatus according to claim 1, wherein the paper information is light transmittance.   4. The paper conveying apparatus according to claim 1, wherein the light emitting unit of the paper information detecting means includes a light amount setting means for changing a light emission amount.   In the paper information detection means, at least two light emitting units emit light with an equivalent light emission amount, and the paper information is obtained from the average value of the output values output from the light receiving unit by receiving light from these light emitting units. 5. A sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus.   6. The paper conveying apparatus according to claim 1, wherein the light emission amount of the light emitting unit and the paper information set by the paper information setting unit are determined corresponding to the type of paper.   6. The light emission amount of the light emitting unit and the paper information set by the paper information setting unit are set corresponding to paper type information input from the outside. Paper transport device.   If the paper information set by the paper information setting means and stored in the paper information storage means is significantly different from the paper information of the original paper transported detected by the paper information detection means, the setting is made without starting the recording operation. 8. The sheet conveying apparatus according to claim 1, further comprising a warning unit that issues a warning to alert the outside whether the printed sheet information is correct.   If the paper information set by the paper information setting means and stored in the paper information storage means is significantly different from the original paper information to be transported detected by the paper information detection means, the light emission means has a predetermined light emission amount. 8. The paper conveying apparatus according to claim 2, wherein the paper information is detected again by detecting the paper information.   10. The paper conveying apparatus according to claim 1, wherein the paper information detecting means also serves as a jam detecting means for outputting a jam signal when no paper is detected at a predetermined time.   An image forming apparatus comprising: the sheet conveying device according to claim 1; and an image forming unit that forms an image.   12. The image forming apparatus according to claim 11, wherein the image forming apparatus is an electrophotographic copying machine.   12. The image forming apparatus according to claim 11, wherein the image forming apparatus is a laser beam printer. 12. The image forming apparatus according to claim 11, wherein the image forming apparatus is a facsimile machine.