JP2013029734A - Image forming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming system capable of shortening the time required for printing when compared with the conventional case when the state of a recording medium is an illegal state.
An image forming system includes an MFP and a side multi-tray that is connected to the MFP and supplies a recording medium to the MFP. The side multi-tray detects the double feeding of the recording medium. The MFP 20 includes a medium state sensor 53 that performs recording and a discharge tray 54 from which the recording medium 91 is discharged. When the medium state sensor 53 detects double feeding, the MFP 20 detects that the double feeding has been detected. A printing stop unit that stops printing and discharges the recording medium 91 to the discharge tray 54 is provided. The medium state sensor 53 fixes the toner image before the toner image is transferred to the intermediate transfer belt 33. It is arranged at a position for detecting double feeding of the scheduled recording medium 91.
[Selection] Figure 1

Description

  The present invention relates to an image forming system including an image forming apparatus that includes a supply device that supplies a recording medium, and an auxiliary supply device that is connected to the image forming apparatus and supplies the recording medium to the image forming apparatus.

  2. Description of the Related Art Conventionally, there has been known an image forming apparatus that prohibits transfer of a toner image to be fixed on a sheet to be conveyed next to a sheet on which double feeding has occurred, to an intermediate transfer body when the double feeding of the sheet has occurred. (For example, refer to Patent Document 1).

  In addition, the printing apparatus includes a paper feeding cassette that supplies paper, and a large-capacity paper feeding deck that is connected to the printing apparatus and supplies paper to the printing apparatus. A printing system is known that includes a double feed detection sensor that detects double feed and an escape tray that discharges paper when double feed is detected by the double feed detection sensor (see, for example, Patent Document 2). .)

Japanese Patent Laid-Open No. 9-80862 JP 2008-180900 A

  However, in the image forming apparatus described in Patent Document 1, since printing is performed on a sheet on which double feeding has occurred, there is a possibility that problems such as a paper jam caused by the paper on which double feeding has occurred may occur. is there. That is, in the image forming apparatus described in Patent Document 1, there is a possibility that the user needs time for eliminating the trouble that has occurred.

  Further, in the printing system described in Patent Document 2, the toner image that is scheduled to be fixed to the paper on which the double feeding has occurred is transferred to the intermediate transfer body of the printing apparatus even when the paper is double fed. There is a possibility that the intermediate transfer member needs to be cleaned. That is, in the printing system described in Patent Document 2, there is a possibility that time for cleaning the intermediate transfer member may be required.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming system capable of reducing the time required for printing when the state of a recording medium is incorrect.

  An image forming system according to the present invention includes an intermediate transfer member on which a toner image which is an image formed with toner and is finally fixed on a recording medium is temporarily transferred, and a supply device for supplying the recording medium And an auxiliary supply device that is connected to the image forming apparatus and supplies the recording medium to the image forming apparatus, and the auxiliary supply device indicates the state of the recording medium. The image forming apparatus includes a medium state sensor to detect and a medium discharge unit from which the recording medium is discharged. The medium state sensor detects that the state of the recording medium is invalid. A printing stop unit that stops printing on the recording medium that is detected to be in an unauthorized state and discharges the recording medium to the medium discharge unit. Nsa, before the toner image is transferred to the intermediate transfer member, characterized in that the toner image is disposed at a position for detecting the state of the recording medium that will be allowed to settle.

  With this configuration, in the image forming system of the present invention, the auxiliary supply device includes a medium discharge unit that discharges the recording medium when the medium state sensor detects that the state of the recording medium is invalid. Therefore, when the recording medium is in an illegal state, it is possible to prevent the recording medium in the illegal state from entering the image forming apparatus from the auxiliary supply device and causing a problem. Therefore, the image forming system according to the present invention has a conventional configuration in which when the state of the recording medium is in an illegal state, the recording medium in the incorrect state enters the image forming apparatus from the auxiliary supply device and causes a problem. Compared with, time for solving the problem is not required. In other words, the image forming system of the present invention can shorten the time required for printing when the state of the recording medium is incorrect. In the image forming system of the present invention, the medium state sensor is disposed at a position for detecting the state of the recording medium on which the toner image is to be fixed before the toner image is transferred to the intermediate transfer member. When the state of the recording medium is an illegal state, it is possible to prevent the toner image that was scheduled to be fixed on the recording medium in the illegal state from being transferred to the intermediate transfer member. Therefore, the image forming system of the present invention does not require time for cleaning the intermediate transfer member as in the conventional configuration when the state of the recording medium is incorrect. In other words, the image forming system of the present invention can shorten the time required for printing when the state of the recording medium is incorrect.

  In addition, the image forming apparatus of the image forming system of the present invention includes a photoconductor on which the toner image is developed, and the medium state sensor detects the toner image before the toner image is developed on the photoconductor. It may be arranged at a position for detecting the state of the recording medium on which the toner image is to be fixed.

  With this configuration, in the image forming system of the present invention, before the toner image is developed on the photosensitive member, the medium state sensor is disposed at a position for detecting the state of the recording medium on which the toner image is to be fixed. Therefore, when the state of the recording medium is an illegal state, it is possible to prevent the toner image that was scheduled to be fixed on the recording medium in an illegal state from being developed on the photosensitive member. Therefore, the image forming system according to the present invention does not require time for the cleaning process of the photosensitive member when the state of the recording medium is incorrect. That is, the image forming system of the present invention can shorten the time required for printing when the recording medium is in an illegal state. In the image forming system of the present invention, the medium state sensor is disposed at a position for detecting the state of the recording medium on which the toner image is to be fixed before the toner image is developed on the photosensitive member. When the state of the recording medium is incorrect, unnecessary toner consumption corresponding to the toner image that was to be developed on the photosensitive member can be prevented.

  The auxiliary supply device of the image forming system of the present invention includes a medium storage portion that stores the recording medium, and an end opposite to the image forming device side of the recording medium stored in the medium storage portion. And a medium transport unit that transports the recording medium to the image forming apparatus.

  With this configuration, the image forming system of the present invention is configured to convey the recording medium from the auxiliary supply device to the image forming device with the end on the image forming device side of the recording medium stored in the medium storage portion of the auxiliary supply device as the leading end. As compared with the above, since the distance until the recording medium stored in the medium storage unit of the auxiliary supply device enters the image forming apparatus is long, the degree of freedom of arrangement of the medium state sensor can be improved.

  Further, the illegal state of the image forming system of the present invention may be double feeding of the recording medium.

  With this configuration, the image forming system of the present invention includes a medium discharge unit that discharges the recording medium when the recording medium is double-fed, so that the recording medium that has been double-fed is clogged. It is possible to prevent problems such as these from occurring in the image forming apparatus.

  The image forming system according to the present invention can shorten the time required for printing when the state of the recording medium is incorrect.

1 is a configuration diagram of an image forming system according to an embodiment of the present invention. It is a block diagram of the image forming system shown in FIG. FIG. 3 is a diagram illustrating timings of drawing control and conveyance control of a control unit shown in FIG. 2 when a recording medium is supplied from a side multi-tray. 3 is a flowchart of the operation of the control unit shown in FIG. 2 when a recording medium is supplied from a side multi-tray. FIG. 4 is a diagram illustrating timings of drawing control and conveyance control of the control unit illustrated in FIG. 2 when a recording medium is supplied from a side multi-tray, which is different from the timing illustrated in FIG. 3. 1 is a configuration diagram of an image forming system according to an embodiment of the present invention, and is a diagram showing a configuration different from the configuration shown in FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  First, the configuration of the image forming system according to the present embodiment will be described.

  FIG. 1 is a configuration diagram of an image forming system 10 according to the present embodiment.

  As shown in FIG. 1, the image forming system 10 includes an MFP (Multifunction Peripheral) 20 and a side multi-tray (Side multi tray) as an auxiliary supply device that is connected to the MFP 20 and supplies a recording medium 91 such as paper to the MFP 20. 50 and a finisher 70 that executes post-processing such as sorting and stapling of the recording medium 91 connected to the MFP 20 and printed by the MFP 20. In the present embodiment, the image forming apparatus according to the present invention includes the MFP 20 and the finisher 70.

  FIG. 2 is a block diagram of the image forming system 10.

  As shown in FIG. 2, the MFP 20 includes a control unit 21 that controls the entire MFP 20, a storage unit 22 that is a storage device such as an EEPROM (Electrically Erasable Programmable Read Only Memory) that stores various data, and a user. The operation unit 23 that is an input device such as a button for inputting various operations by the computer, the display unit 24 that is a display device such as an LCD (Liquid Crystal Display) that displays various information, and printing on the recording medium 91 A printer 25 that performs printing, a scanner 26 that reads an image from a document, and a fax device that performs fax communication with an external facsimile apparatus (not shown) via a communication line such as a public telephone line. A facsimile communication part 27 is provided with a a LAN (Local Area Network) network communication unit 28 is a network communication device which communicates with an external apparatus via a network, such as.

  The control unit 21 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores programs and various data in advance, and a RAM (Random Access Memory) used as a work area of the CPU. ing. The CPU is configured to execute a program stored in the ROM or the storage unit 22.

  The storage unit 22 stores an image forming apparatus program 22 a that is a program for the MFP 20.

  Note that the image forming apparatus program 22a may be installed in the MFP 20 at the manufacturing stage of the MFP 20, or may be installed from a storage medium such as a CD (Compact Disk) or a DVD (Digital Versatile Disk), or from the network to the MFP 20. It may be installed additionally.

  By executing the image forming apparatus program 22a stored in the storage unit 22, the control unit 21 detects a double feed when an incorrect state double feed is detected by a medium state sensor 53 described later. It functions as a print cancel unit 21 a that stops printing on the recording medium 91 and discharges the recording medium 91 to a discharge tray 54 described later.

  As shown in FIG. 1, the printer 25 includes a plurality of trays 31a for storing the recording medium 91 and supplies the recording medium 91. The printer 25 is an image formed by toner and finally the recording medium. Cyan, magenta, yellow, and black photosensitive drums 32a to 32d as photosensitive members on which a toner image to be fixed on 91 is developed, and toner images developed on the photosensitive drums 32a to 32d are temporarily An intermediate transfer belt 33 as an intermediate transfer member transferred to the recording medium, a transfer roller 34 for transferring the toner image transferred to the intermediate transfer belt 33 to the recording medium 91, and the toner image transferred to the recording medium 91 recorded by heat. A fixing roller 35 for fixing to the medium 91, a pressure roller 36 for pressing the recording medium 91 against the fixing roller 35, and intermediate transfer The recording roller 91 includes a registration roller 37 for adjusting the conveyance timing of the recording medium 91 to the toner image transferred to the belt 33, a discharge tray 38 for discharging the printed recording medium 91, and a plurality of conveyance rollers 39a. And a transport unit 39 that transports the medium 91.

  The side multi-tray 50 includes a plurality of trays 51a serving as a plurality of medium storage units that store the recording medium 91, a medium supply sensor 52 that detects that the recording medium 91 is supplied from the tray 51a, and the state of the recording medium 91. A medium state sensor 53 for detecting the recording medium, a discharge tray 54 as a medium discharge unit from which the recording medium 91 is discharged, and a medium conveyance unit 55 that includes a plurality of conveyance rollers 55a and conveys the recording medium 91. .

  The medium state sensor 53 is disposed at a position for detecting the state of the recording medium 91 to which the toner image is to be fixed before the toner image is developed on the photosensitive drums 32a to 32d. The medium state sensor 53 detects double feeding of the recording medium 91 as an illegal state of the recording medium 91. The medium state sensor 53 includes an ultrasonic transmission unit and an ultrasonic reception unit, and is an amount attenuated by the recording medium 91 from when the ultrasonic wave is transmitted from the transmission unit to when it is received by the reception unit. Thus, double feeding of the recording medium 91 is detected.

  The medium transport unit 55 transports the recording medium 91 to the MFP 20 with the end opposite to the MFP 20 side of the recording medium 91 stored in the tray 51a as the leading end.

  The finisher 70 includes discharge trays 71 and 72 from which the recording medium 91 printed by the MFP 20 is discharged, and a transport unit 73 that includes a plurality of transport rollers 73 a and transports the recording medium 91.

  Next, the operation of the image forming system 10 will be described.

  The control unit 21 of the MFP 20 of the image forming system 10 includes, for example, print data based on image data read by the scanner 26 for copying, print data based on fax data received via the fax communication unit 27, network Printing is performed by the printer 25 based on various types of print data such as print data received via the communication unit 28. Here, the control unit 21 can convey the recording medium 91 for printing by the printer 25 not from the tray 31a but from the tray 51a in the side multi-tray 50 according to the information in the print data.

  FIG. 3 is a diagram illustrating the drawing control and transport control timings of the control unit 21 when the recording medium 91 is supplied from the side multi-tray 50.

As shown in FIG. 3, when the control unit 21 starts printing at time t ₀ based on the print data, the control unit 21 causes the medium transport unit 55 of the side multi-tray 50 to start transporting the recording medium 91 at time t ₁ . Here, the medium conveyance unit 55 conveys the recording medium 91 from the tray 51a instructed in the print data among the plurality of trays 51a.

When the recording medium 91 is conveyed from the tray 51 a by the medium conveying unit 55, the control unit 21 detects the recording medium 91 being conveyed by the medium conveying unit 55 by the medium supply sensor 52. When this, the time _{t 2.}

When the recording medium 91 is further conveyed by the medium conveying unit 55, the control unit 21 detects the recording medium 91 being conveyed by the medium conveying unit 55 by the medium state sensor 53. When this, the time _{t 3.} Therefore, the control unit 21 starts determination at the time t ₃ based on the detection result of the medium state sensor 53 whether or not double feeding has occurred in the recording medium 91 conveyed by the medium conveying unit 55. This determination is continued until the time t _4.

Control unit 21, a development of the toner image on the photosensitive drum 32 a to 32 d, starting at time _{t 5} a predetermined time after the time _{t 2.} Then, the toner image developed on the photosensitive drum 32a~32d is transferred to the intermediate transfer belt 33 is started at time _{t 6.} Transfer to the intermediate transfer belt 33 ends at time t _7.

Then, the control unit 21, once stopped at time t ₈ at the position of the resist roller 37 to the recording medium 91 based on the detection result on the registration sensor (not shown).

  Thereafter, the control unit 21 conveys the recording medium 91 by the registration roller 37 in synchronization with the toner image transferred to the intermediate transfer belt 33.

  When the recording medium 91 is supplied from the side multi-tray 50, the control unit 21 performs the drawing control and the conveyance control at the timing shown in FIG. 3, so that the control unit 21 can operate as shown in FIG. .

  FIG. 4 is a flowchart of the operation of the control unit 21 when the recording medium 91 is supplied from the side multi-tray 50.

  As shown in FIG. 4, the control unit 21 causes the medium transport unit 55 of the side multi-tray 50 to start transporting the recording medium 91 (S101).

  Next, the control unit 21 determines based on the detection result of the medium state sensor 53 whether or not double feeding has occurred in the recording medium 91 conveyed by the medium conveying unit 55 (S102).

  When the print cancel unit 21a of the control unit 21 determines in S102 that double feed has occurred, the print cancel unit 21a stops printing on the recording medium 91 that has determined that double feed has occurred (S103). 91 is discharged to the discharge tray 54 of the side multi-tray 50 by the medium transport section 55 (S104). Therefore, in the image forming system 10, the recording medium 91 in which double feeding has occurred, such as a problem that the recording medium 91 is clogged in the MFP 20 or a toner image is not properly transferred to the recording medium 91, is transferred from the side multi-tray 50 to the MFP 20. It is possible to prevent inconvenience caused by entering.

  The control unit 21 ends the process illustrated in FIG. 4 after the process of S104. And the control part 21 starts the process shown in FIG. 4 again based on the print data which stopped printing.

  If the control unit 21 determines in S102 that the multi-feed has not occurred, the control unit 21 starts developing the toner image on the photosensitive drums 32a to 32d (S105). The toner images developed on the photosensitive drums 32 a to 32 d are temporarily transferred to the intermediate transfer belt 33 and then transferred to the recording medium 91 by the transfer roller 34. Next, the toner image transferred to the recording medium 91 is fixed to the recording medium 91 by the fixing roller 35 and the pressure roller 36.

  After the process of S105, the control unit 21 discharges the recording medium 91 on which the toner image is fixed to the discharge tray 38, 71 or 72 (S106), and ends the process shown in FIG. Note that it is specified in the print data which of the discharge trays 38, 71 and 72 the recording medium 91 is discharged to.

  As described above, in the image forming system 10, the side multi-tray 50 includes the discharge tray 54 from which the recording medium 91 is discharged when the medium state sensor 53 detects double feeding of the recording medium 91. When the double feeding of the recording medium 91 occurs, it is possible to prevent the recording medium 91 in which the double feeding has occurred from entering the MFP 20 from the side multi-tray 50 and causing a problem. Therefore, the image forming system 10 is compared with the conventional configuration in which when the recording medium 91 is double-fed, the recording medium 91 that has been double-fed enters the MFP 20 from the side multi-tray 50 and causes a problem. This eliminates the need for time to resolve the problem. That is, the image forming system 10 can shorten the time required for printing when the double feeding of the recording medium 91 occurs.

  In the image forming system 10, before the toner image is developed on the photosensitive drums 32a to 32d, the medium state sensor 53 is arranged at a position to detect double feeding of the recording medium 91 on which the toner image is to be fixed. Therefore, when the double feeding of the recording medium 91 occurs, it is possible to prevent the toner image that was scheduled to be fixed to the recording medium 91 where the double feeding occurred from being developed on the photosensitive drums 32a to 32d. it can. Therefore, the image forming system 10 does not require time for cleaning the photosensitive drums 32a to 32d by a cleaning mechanism (not shown) when the recording medium 91 is double-fed. That is, the image forming system 10 can shorten the time required for printing when the double feeding of the recording medium 91 occurs.

  In the image forming system 10, before the toner image is developed on the photosensitive drums 32a to 32d, the medium state sensor 53 is arranged at a position to detect double feeding of the recording medium 91 on which the toner image is to be fixed. Therefore, when double feeding of the recording medium 91 occurs, it is possible to prevent unnecessary consumption of toner corresponding to the toner image that was to be developed on the photosensitive drums 32a to 32d.

  In the image forming system 10, before the toner image is transferred to the intermediate transfer belt 33, the medium state sensor 53 is arranged at a position for detecting double feeding of the recording medium 91 to which the toner image is to be fixed. Then, as shown in FIG. 5, after the toner image starts to be developed on the photosensitive drums 32a to 32d, the medium state sensor 53 is located at a position where the double feeding of the recording medium 91 to which the toner image is to be fixed is detected. May be arranged.

  In the image forming system 10, before the toner image is transferred to the intermediate transfer belt 33, the medium state sensor 53 is disposed at a position to detect double feeding of the recording medium 91 to which the toner image is to be fixed. When the double feeding of the recording medium 91 occurs, it is possible to prevent the toner image that was scheduled to be fixed to the recording medium 91 where the double feeding occurred from being transferred to the intermediate transfer belt 33. Therefore, the image forming system 10 does not need time for cleaning the intermediate transfer belt 33 by a cleaning mechanism (not shown) when the recording medium 91 is double-fed. That is, the image forming system 10 can shorten the time required for printing when the double feeding of the recording medium 91 occurs. In the image forming system 10, when the recording medium 91 is double-fed and the toner images are already developed on the photosensitive drums 32 a to 32 d, the photosensitive drums 32 a to 32 d by a cleaning mechanism (not shown) are used. It is sufficient to execute only the cleaning process.

  As shown in FIG. 1, the image forming system 10 conveys the recording medium 91 to the MFP 20 with the end opposite to the MFP 20 side of the recording medium 91 stored in the tray 51 a of the side multi-tray 50 as the leading end. Therefore, as shown in FIG. 6, the recording medium 91 stored in the tray 51a of the side multi-tray 50 is compared with a configuration in which the recording medium 91 is conveyed from the side multi-tray 50 to the MFP 20 with the end on the MFP 20 side as the leading end. Thus, the distance until the recording medium 91 stored in the tray 51a of the side multi-tray 50 enters the MFP 20 is long. Therefore, the image forming system 10 can improve the degree of freedom of arrangement of the medium state sensor 53.

  6, the image forming system 10 conveys the recording medium 91 from the side multi-tray 50 to the MFP 20 with the end on the MFP 20 side of the recording medium 91 stored in the tray 51a of the side multi-tray 50 as the leading end. It may be like this.

  In the image forming system 10, the side multi-tray 50 includes the discharge tray 54 from which the recording medium 91 is discharged when the recording medium 91 is double-fed. It is possible to prevent a problem from occurring in the MFP 20.

  Note that, as the double feed detection method, the ultrasonic method is employed in the present embodiment, but any known method other than the ultrasonic method may be employed.

  The medium state sensor 53 detects double feeding of the recording medium 91 as an illegal state of the recording medium 91 in the present embodiment, but detects an illegal state other than double feeding. Also good.

  For example, the medium state sensor 53 may be configured to detect that the recording medium 91 is being conveyed obliquely as an illegal state of the recording medium 91. When the medium state sensor 53 detects that the recording medium 91 is being conveyed obliquely as an illegal state of the recording medium 91, the image forming system 10 has a problem such as a clogging of the recording medium 91 being conveyed obliquely. Since it can be prevented from occurring in the MFP 20, the time required for printing can be shortened as in the case of detecting double feeding of the recording medium 91 as an illegal state of the recording medium 91. In addition, as a method for detecting that the recording medium 91 is being transported obliquely, for example, two optical sensors arranged on the transport path of the recording medium 91 apart in a direction perpendicular to the transport direction of the recording medium 91 are used. Any known method such as a method of detecting the tilt of the recording medium 91 can be employed.

  Further, the medium state sensor 53 may detect that the size of the recording medium 91 being conveyed is different from the size specified by the user as an incorrect state of the recording medium 91. When the medium state sensor 53 detects that the size of the recording medium 91 being conveyed is different from the size specified by the user as an illegal state of the recording medium 91, the image forming system 10 is specified by the user. Since it is possible to prevent problems such as clogging of the recording medium 91 having a size different from the current size from occurring in the MFP 20, a case where the double feeding of the recording medium 91 is detected as an illegal state of the recording medium 91 and Similarly, the time required for printing can be shortened. Further, when the medium state sensor 53 detects that the size of the recording medium 91 being conveyed is different from the size specified by the user as an illegal state of the recording medium 91, the image forming system 10 may be It is possible to prevent the inside of the MFP 20 from being contaminated with toner by printing on the recording medium 91 having a size smaller than the designated size. In addition, as a method for detecting the size of the recording medium 91 being conveyed, for example, the recording medium 91 may be detected by a plurality of optical sensors arranged in a direction orthogonal to the conveyance direction of the recording medium 91 on the conveyance path of the recording medium 91. A method for detecting the horizontal width, a method for detecting the vertical width of the recording medium 91 by detecting the passing time of the recording medium 91 passing over the optical sensor by an optical sensor arranged on the conveyance path of the recording medium 91, and the like. Any method can be employed.

  Further, the medium state sensor 53 may detect that the conveyance of the recording medium 91 is delayed as an incorrect state of the recording medium 91. When the medium state sensor 53 detects that the conveyance of the recording medium 91 is delayed as an illegal state of the recording medium 91, the image forming system 10 detects double feeding of the recording medium 91 as an illegal state of the recording medium 91. As in the case of performing, the time required for the cleaning process of the intermediate transfer belt 33 is not required, so that the time required for printing can be shortened. In addition, as a method of detecting that the conveyance of the recording medium 91 is delayed, for example, a method of detecting the timing at which the recording medium 91 has reached the optical sensor by an optical sensor arranged on the conveyance path of the recording medium 91. Any known method can be employed.

  The image forming apparatus of the present invention includes not only the MFP but also the finisher in the present embodiment, but it may be only the MFP.

  The image forming apparatus of the present invention is an MFP in the present embodiment, but may be an image forming apparatus other than the MFP, such as a printer dedicated machine.

10 image forming system 20 MFP (image forming apparatus)
21a Printing stop means 31 Supply device 32a to 32d Photosensitive drum (photosensitive member)
33 Intermediate transfer belt (intermediate transfer member)
50 Side multi-tray (auxiliary supply device)
51a Tray (medium storage part)
53 Media status sensor 54 Ejection tray (medium ejection part)
55 Medium Conveying Unit 70 Finisher (Image Forming Apparatus)
91 Recording media

Claims (4)

An image forming apparatus comprising: an intermediate transfer body on which a toner image that is an image formed with toner and is finally fixed on a recording medium is temporarily transferred; and a supply device that supplies the recording medium And an auxiliary supply device connected to the image forming apparatus and supplying the recording medium to the image forming apparatus,
The auxiliary supply device includes a medium state sensor that detects a state of the recording medium, and a medium discharge unit that discharges the recording medium.
When the medium state sensor detects that the state of the recording medium is an invalid state, the image forming apparatus stops printing on the recording medium that is detected to be the invalid state, and Printing stop means for discharging the recording medium to the medium discharge unit,
The medium state sensor is disposed at a position for detecting a state of the recording medium to which the toner image is to be fixed before the toner image is transferred to the intermediate transfer member. Forming system. The image forming apparatus includes a photoreceptor on which the toner image is developed,
The medium state sensor is disposed at a position for detecting a state of the recording medium on which the toner image is to be fixed before the toner image is developed on the photoconductor. 2. The image forming system according to 1.   The auxiliary supply device includes a medium storage unit for storing the recording medium, and an end of the recording medium stored in the medium storage unit opposite to the image forming apparatus side as a leading end. The image forming system according to claim 1, further comprising a medium transport unit that transports the image forming apparatus to the forming apparatus.   4. The image forming system according to claim 1, wherein the illegal state is a double feed of the recording medium.

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