Conveyance failure determination device and printing device

Abstract

To provide a conveyance failure determination device and a printing device that can reduce a workload of a user because of a conveyance failure.SOLUTION: The conveyance failure determination device includes: a floating detection part 70 that is provided between a printing part 30 for performing print processing on a printing medium P and a feeding part (side paper feeding part 10 and internal paper feeding part 20) for feeding the printing medium P to the printing part 30, and detects floating of the printing medium P fed from the feeding part; and a determination part 61 that determines a conveyance failure of the printing medium P based on detection results of the floating detection part 70. The determining part 61 does not determine that there is a conveyance failure even when the floating of the printing medium P is detected during a period from when a feed of the printing medium P from the feeding part is started until when the preset number of sheets are fed, and determines that there is a conveyance failure when the floating of the printing medium P is detected from the point of time when the preset number of the next printing media are fed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a conveyance failure determination device and a printing device that determine conveyance failure based on the result of detecting floating of a print medium. [Background technology]

[0002] 2. Description of the Related Art Conventionally, it has been proposed to provide a detection unit, such as a sensor, for detecting the print medium on a print medium transport path of a printing device, and to perform predetermined control based on the detection results of the detection unit.

[0003] For example, Patent Document 1 proposes that the length of the first transported printing medium be measured by a detection unit, and if the measured length is longer than a preset length, the feeding of the second sheet of printing paper be stopped.

[0004] Furthermore, Patent Document 2 proposes detecting the leading edge of the printing medium and imaging the surface of the printing medium following that leading edge to determine whether the surface of the printing medium has already been printed, and if so, stopping the operation of the device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-230828 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-112814 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when using the manual paper feed tray of a printing device, for example, the user may unintentionally deform the print medium, causing the print medium to float up. This refers to a state in which the print medium is warped and rises above the normal transport path (transport surface).

[0007] When such floating occurs, if a detection unit installed on the transport path were to simply detect the floating and determine that there is a transport problem, and then stop the paper feed of the printing device, there would be a problem that the printing device would stop frequently, increasing the workload for the user to deal with the transport problem.

[0008] In view of the above circumstances, an object of the present invention is to provide a conveyance failure determination device and a printing device that can reduce the workload on the user in dealing with conveyance failures. [Means for solving the problem]

[0009] The transport failure determination device of the present invention is provided between a printing unit that performs printing processing on print media and a supply unit that supplies print media to the printing unit, and is equipped with a float detection unit that detects floating of print media supplied from the supply unit, and a determination unit that determines transport failure of the print media based on the detection results by the float detection unit, and the determination unit does not determine transport failure even if floating of the print media is detected from the time the supply unit starts to supply print media until a predetermined number of sheets have been supplied, but determines transport failure if floating of the print media is detected from the time the next predetermined number of sheets of print media are supplied. [Effects of the Invention]

[0010] According to the transport failure determination device of the present invention, from the start of supply of printing media from the supply unit until a predetermined number of sheets have been supplied, even if floating of the printing media is detected, it is not determined to be a transport failure, but from the point when the next predetermined number of sheets of printing media have been supplied, if floating of the printing media is detected, it is determined to be a transport failure, thereby reducing the user's workload regarding transport failures. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing a schematic configuration of an embodiment of an inkjet printing apparatus of the present invention; [Figure 2] FIG. 2 is a block diagram showing the schematic configuration of a control system of the inkjet printing apparatus shown in FIG. 1. [Figure 3] A flowchart for explaining a method for determining a print medium transport failure in the inkjet printing device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] An inkjet printing apparatus using an embodiment of the transport failure determination device of the present invention will be described in detail below with reference to the drawings. The inkjet printing apparatus of this embodiment is characterized by a method for determining transport failure of a print medium, but first, its overall configuration will be described. FIG. 1 is a diagram showing a schematic configuration of an inkjet printing apparatus 1 of this embodiment. The up, down, left, and right directions shown in FIG. 1 are the up, down, left, and right directions of the inkjet printing apparatus 1 of this embodiment. The front side of the paper in FIG. 1 is the front direction, and the back side of the paper is the rear direction.

[0013] 1, the inkjet printing device 1 of this embodiment includes a side paper feed unit 10, an internal paper feed unit 20, a printing unit 30, a paper discharge unit 40, and an inverting unit 50. In this embodiment, the side paper feed unit 10 and the internal paper feed unit 20 correspond to the supply unit of the present invention.

[0014] The printing unit 30 and the internal paper feed unit 20 are housed and installed in a housing made of metal, resin, etc. The side paper feed unit 10 and the paper discharge unit 40 are installed with a portion housed within the housing and a portion protruding outside the housing.

[0015] The side paper feed section 10 is what is called a manual paper feed tray, and is equipped with a paper feed tray 11 on which the printing medium P is placed, a primary paper feed section 12 that feeds out and transports only the topmost printing medium P from the paper feed tray 11, and a secondary paper feed section 14 that sends the printing medium P transported by the primary paper feed section 12 to the printing section 30 at a predetermined timing.

[0016] The secondary paper feed section 14 is equipped with a registration roller 14a that forms slack by contacting the leading edge of the printing medium P transported from the primary paper feed section 12 or the internal paper feed section 20, thereby stopping the printing medium P and correcting skew, and a registration motor (not shown) that drives the registration roller 14a.

[0017] The internal paper feeding unit 20 includes a paper feeding tray 21a on which the printing medium P is placed, a primary paper feeding unit 22a that feeds only the uppermost printing medium P from the paper feeding tray 21a and transports it onto the paper feeding transport path FR, a paper feeding tray 21b on which the printing medium P is placed, a primary paper feeding unit 22b that feeds only the uppermost printing medium P from the paper feeding tray 21b and transports it onto the paper feeding transport path FR, a paper feeding tray 21c on which the printing medium P is placed, and a primary paper feeding unit 22c that feeds only the uppermost printing medium P from the paper feeding tray 21c and transports it onto the paper feeding transport path FR.

[0018] As described above, the printing medium P is transported to the secondary paper feed unit 14 from the side paper feed unit 10 or the internal paper feed unit 20, and also from the inverting unit 50, which will be described later.

[0019] Therefore, just before the secondary paper feed unit 14 in the transport direction, there is a junction where the transport path for the printing medium P fed from the side paper feed unit 10 or the internal paper feed unit 20 and the transport path for the printing medium P printed on one side and transported from the reversing unit 50 join together. Based on this junction, the path on the paper feed mechanism side is called the paper feed transport path FR, and the other path is called the circulating transport path CR.

[0020] In addition, a number of paper detection sensors (not shown) that detect the printing medium P are provided on the circulating conveying path CR, and the conveying of the printing medium P is controlled by the control unit 60, which will be described later, based on the detection signals detected by the paper detection sensors.

[0021] The printing unit 30 includes four line heads 31, a circular conveyor belt 32 disposed opposite the line heads 31, a first belt platen roller 33, and a second belt platen roller .

[0022] The conveyor belt 32 is formed from a circular endless belt and has many suction holes formed therein. The printing medium P fed from the secondary paper feed unit 14 is conveyed to the circular conveyor belt 32. The printing medium P is then attracted to the conveyor belt 32 by the suction of a suction fan (not shown) installed on the back side of the conveying path surface of the conveyor belt 32, and is conveyed at a predetermined conveying speed. Then, while the printing medium P is conveyed by the conveyor belt 32, ink is ejected from the line head 31 onto the printing medium P, thereby subjecting the printing medium P to a printing process.

[0023] A conveying belt 32 is stretched between the first belt platen roller 33 and the second belt platen roller 34, and the first belt platen roller 33 and the second belt platen roller 34 are driven by a conveying motor (not shown), causing the conveying belt 32 to rotate clockwise in Figure 1.

[0024] In addition, a lift detection unit 70 is provided between the conveyor belt 32 and the registration rollers 14a. The lift detection unit 70 detects lifting of the print medium P, and includes a swing unit 70a and a swing sensor unit 70b.

[0025] The swinging portion 70a is a member that extends in a direction (front-rear direction) perpendicular to the transport direction of the print medium P. The swinging portion 70a is formed so that the cross section of the plane perpendicular to the extension direction thereof has a crank shape.

[0026] The swinging unit 70a is rotatably supported by a support shaft 70c extending in the transport direction of the printing medium P, and is supported so as to be swingable in the direction of arrow A shown in FIG. 1 and the opposite direction. When the printing medium P transported from the registration rollers 14a is lifted, the leading edge of the printing medium P in the transport direction comes into contact with one end of the swinging unit 70a, which pushes the swinging unit 70a forward and swings it in the direction of arrow A. This swing causes the other end of the swinging unit 70a to disengage from the swing sensor unit 70b. This makes it possible to detect whether the printing medium P has lifted by a predetermined amount or more.

[0027] The swinging unit 70a is installed so that the printing medium P passes under the swinging unit 70a when the printing medium P is not lifted or when the lifted amount is less than a predetermined amount. The distance between one end of the swinging unit 70a and the conveyor belt 32 is set to be equal to or less than the distance between each line head 31 and the conveyor belt 32, thereby preventing the printing medium P from colliding with each line head 31.

[0028] In addition, the length L of the oscillating portion 70a in the direction perpendicular to the transport direction of the printing medium P is set to be longer than the length of the A3 size in the direction perpendicular to the transport direction, for example, if the largest size of the printing medium P expected to be used is A3 size.

[0029] As described above, the swing sensor unit 70b detects whether the swing unit 70a is in contact or not, and outputs a detection signal to the control unit 60. The determination unit 61 in the control unit 60, which will be described later, determines whether the print medium P is being transported properly based on the detection result of the lift detection unit 70, and the method of this determination will be described in detail later.

[0030] Each line head 31 extends in a direction perpendicular to the transport direction of the print medium P, and ejects ink onto the print medium P transported by the transport belt 32. As shown in Fig. 1, the four line heads 31 are arranged at predetermined intervals along the transport path of the print medium P. Each of the four line heads 31 ejects CMYK ink.

[0031] The print medium P printed by the printing unit 30 is transported on the circulating transport path CR by transport rollers and the like arranged on the circulating transport path CR. A switching mechanism 43 is provided on the circulating transport path CR, which switches between guiding the print medium P transported on the circulating transport path CR to the paper discharge unit 40 or recirculating the print medium P on the circulating transport path CR. Specifically, the switching mechanism 43 switches between the transport path on the paper discharge unit 40 side and the transport path on the reversing unit 50 side.

[0032] The paper discharge unit 40 has a tray-shaped paper discharge table 41 that protrudes from the housing of the inkjet printing device 1, and a pair of paper discharge rollers 42 that discharge the printing medium P onto the paper discharge table 41. The printing medium P that has been guided toward the paper discharge unit 40 by the switching mechanism 43 is then discharged onto the paper discharge table 41 by the paper discharge rollers 42.

[0033] The inversion unit 50 includes an inversion table 51 having an inversion transport path SR for inverting the printing medium P, an inversion roller 52 that transports the printing medium P from the circulating transport path CR to the inversion table 51 and returns the printing medium P transported to the inversion table 51 onto the circulating transport path CR, and an inversion motor (not shown) that drives the inversion roller 52.

[0034] The printing medium P guided to the reversing unit 50 by the switching mechanism 43 is transported from the circulating conveying path CR to the reversing table 51 by the reversing rollers 52, and then returned from the reversing table 51 to the circulating conveying path CR, whereby the printing medium P is transported upside down on the circulating conveying path CR. Then, the printing medium P, now upside down, is transported again toward the printing unit 30 by a plurality of rollers, such as the transport roller 53, provided on the circulating conveying path CR.

[0035] The print medium P transported by the transport rollers 53 is transported again to the registration rollers 14a of the secondary paper feed unit 14, and is sent out again at a predetermined timing by the registration rollers 14a toward the printing unit 30. Then, after passing under the swinging unit 70a, the printing unit 30 performs printing on the back side of the print medium P.

[0036] FIG. 2 is a block diagram showing a schematic configuration of a control system of the inkjet printing apparatus 1 of this embodiment.

[0037] The control unit 60 controls the entire inkjet printing apparatus 1, and includes a CPU (Central Processing Unit), a semiconductor memory, etc. The control unit 60 controls the operation of each part of the inkjet printing apparatus 1 by having the CPU execute a program stored in advance in the semiconductor memory.

[0038] The control unit 60 also acquires image data output from a computer or read by a scanner, and controls the printing unit 30 to perform printing processing based on the image data.

[0039] The control unit 60 also includes a determination unit 61. The determination unit 61 determines whether the print medium P is being transported properly based on the detection result from the lift detection unit 70. If the determination unit 61 determines that the print medium P is being transported properly, the control unit 60 stops the operation of the supply system, such as the side paper feed unit 10, the internal paper feed unit 20, and the reversing unit 50, or stops the operation of the supply system and the printing unit 30.

[0040] Specifically, the determination unit 61 of this embodiment has a counter that counts the number of sheets of printing medium P supplied from the side paper feed unit 10 or the internal paper feed unit 20. Then, from the start of supplying the printing medium P for a specific print job until a preset number of sheets have been supplied, the determination unit 61 does not determine that a conveyance error has occurred even if floating of the printing medium P is detected.

[0041] Furthermore, if floating of the printing medium P is detected after the preset number of sheets of the next printing medium P has been supplied, the determination unit 61 determines that a conveyance failure has occurred.

[0042] In this embodiment, the preset number is 1. That is, if the supplied printing medium P is the first (first sheet) of printing medium P for a specified print job, the determination unit 61 does not determine that a transport error has occurred even if floating of the printing medium P is detected, and continues transporting the printing medium P and printing processing. On the other hand, if the supplied printing medium P is the second or subsequent sheet of printing medium for a specified print job, the determination unit 61 determines that a transport error has occurred if floating is detected.

[0043] In this way, for the first (first) sheet of printing medium P, which is prone to sudden deformation, even if lifting of that printing medium P is detected, it is not judged as a transport failure, and if lifting is detected for the second or subsequent sheets of printing medium, it is judged as a transport failure, thereby reducing the workload on the user due to transport failure.

[0044] Furthermore, the determination unit 61 acquires attribute information of the supplied printing medium P and switches the method of determining whether or not the conveyance has been impaired based on the attribute information. The attribute information of the printing medium P is information about the properties of the printing medium P, such as information about the hardness, thickness, and size of the printing medium P, but other information may also be used. The attribute information of the printing medium P may be acquired from setting information included in the print job, or may be acquired from information entered and set on an operation panel (not shown) provided on the inkjet printing device 1.

[0045] The determination unit 61 of this embodiment acquires information on the paper type of the printing medium P (plain paper, coated paper, fine paper, special paper, thick paper, etc.) as information on the hardness of the printing medium P. Then, if the acquired paper type information is information on a soft paper type, as described above, in the case of the first (first sheet) of printing medium, the determination unit 61 does not determine that a transport failure has occurred even if floating of the printing medium P is detected, but in the case of the second or subsequent sheets of printing medium, the determination unit 61 determines that a floating of the printing medium P has occurred (this corresponds to the first determination method of the present invention).

[0046] On the other hand, if the acquired paper type information is not information about a soft paper type, i.e., information indicating a paper type having a predetermined hardness or greater, the judgment unit 61 judges that the judgment is poor regardless of the number of sheets of printing medium P supplied, i.e., even if it is the first (first) sheet of printing medium, if floating of the printing medium P is detected (corresponding to the second judgment method of the present invention).

[0047] If the printing medium P is hard, there is a risk that the printing medium P will collide with the line head 31 and be damaged, so by determining that there is a transport problem from the first printing medium P as described above, it is possible to prevent damage to the line head 31.

[0048] In this embodiment, the first and second determination methods are switched depending on the hardness of the printing medium P, but this is not limiting, and the first and second determination methods may be switched based on information about the thickness of the printing medium P. Specifically, the determination unit 61 may determine a transport failure using the first determination method when the paper type information indicates thin paper, and may determine a transport failure using the second determination method when the paper type information indicates thick paper.

[0049] In addition, the judgment unit 61 has a preset relationship between the attribute information of the printing medium P and the first or second judgment method, and the judgment unit 61 switches between the first judgment method and the second judgment method based on the acquired attribute information of the printing medium P (for example, information on the type of paper) and the above relationship.

[0050] Next, a method for determining whether or not the print medium P is being transported properly in the inkjet printing device 1 of this embodiment will be described with reference to the flowchart shown in Figure 3. Note that the flowchart does not include in the count the number of sheets of paper that have passed through the reverse path during double-sided printing.

[0051] First, the control unit 60 waits for a print instruction for the print job (S10, NO), and when a print instruction is received (S10, YES), it starts supplying the print medium P. Specifically, the control unit 60 starts supplying the print medium P from the side paper feed unit 10 or the internal paper feed unit 20 to the printing unit 30 (S12).

[0052] The determination unit 61 then monitors whether or not the lifting of the printing medium P is detected by the lift detection unit 70 (S14), that is, whether or not the swing sensor unit 70b has output a detection signal for the printing medium P. If the determination unit 61 detects the lifting of the printing medium P (S14, YES), it checks whether or not the printing medium P is a soft printing medium (S16).

[0053] Next, if the printing medium P is a flexible printing medium (S16, YES), the determination unit 61 checks whether the printing medium P is the second or subsequent printing medium P of the print job (S18). If the printing medium P is not the second or subsequent printing medium P (S18, NO), that is, if it is the first (first) printing medium P of the print job, the determination unit 61 does not determine that there is a transport failure (first determination method), but returns to S14 and again monitors the floating of the second or subsequent printing medium P (S14). The first printing medium P is transported directly to the printing unit 30 and subjected to printing processing.

[0054] On the other hand, if it is confirmed in S18 that the printing medium P is the second or subsequent sheet (S18, YES), the determination unit 61 determines that there is a transport failure, and the control unit 60 stops the operation of the supply system and the printing unit 30 in accordance with the determination result (S20). That is, the operation of the supply system and the printing unit 30 is stopped in response to the floating of the printing medium P. Then, for example, after the floating printing medium P is removed, the control unit 60 resumes the supply of the printing medium P from the supply system. At this time, the counter used in S18 to determine whether the printing medium P is the second or subsequent sheet is reset and starts counting again from "1."

[0055] Furthermore, in S16, if the determination unit 61 determines that the printing medium P is not a soft printing medium (S16, NO), the determination unit 61 determines that a transport failure has occurred regardless of whether the printing medium P is the first (first sheet) printing medium P of the print job (second determination method), and the control unit 60 stops the operation of the supply system and the printing unit 30. Then, in this case as well, the counter for determining whether the printing medium P is the second or subsequent sheet of printing medium P is reset in S18 and starts counting again from "1."

[0056] Furthermore, in S14, if floating of the printing medium P is not detected (S14, NO) and the processing of the print job has not ended (S22, NO), the process returns to S14, and the determination unit 61 monitors floating of the sequentially supplied printing medium P. Then, if the processing of the print job has ended without detecting floating of the printing medium P (S22, YES), the control unit 60 stops the operation of the supply system and the printing unit 30 and ends the processing (S20).

[0057] As in the above embodiment, by switching between the first and second determination methods based on the softness (hardness) of the printing medium P, the first determination method is adopted when the printing medium P is soft, thereby reducing the workload on the user due to the occurrence of transport problems. On the other hand, by adopting the second determination method when the printing medium P is hard, damage to the line head 31 due to collision of the printing medium P with the line head 31 can be prevented.

[0058] Furthermore, in the above embodiment, if the printing medium P is soft, the first printing medium P is not judged as having a transport failure even if floating is detected, and if floating is detected for the second or subsequent printing medium P, it is judged as having a transport failure. However, the number of printing media P for which floating is not judged as having a transport failure even if floating is detected is not limited to one, and may be set to two or more.

[0059] Furthermore, the number of sheets of printing medium P that are not determined to be defective even when floating is detected may be changed based on the attribute information of the printing medium P. In the above embodiment, when the printing medium P is soft, the number of sheets of printing medium P that are not determined to be defective is set to one, and when the printing medium P is hard, the number of sheets of printing medium P that are not determined to be defective may be set to zero. However, this is not limiting, and when the printing medium P is soft, the number of sheets of printing medium P that are not determined to be defective may be set to two, and when the printing medium P is hard, the number of sheets of printing medium P that are not determined to be defective may be set to one.

[0060] In this way, by changing the number of sheets of printing medium P that will not be judged as defective even if floating is detected based on the hardness of the printing medium P, it is possible to both reduce the user's workload for defective judgment and prevent damage to the line head 31.

[0061] Furthermore, if the printing medium P is thin, the number of sheets of printing medium P that will not be determined as defective may be set to 2, and if the printing medium P is thick, the number of sheets of printing medium P that will not be determined as defective may be set to 1. In other words, the number of sheets of printing medium P that will not be determined as defective may be changed based on the attribute information of the printing medium P.

[0062] In this way, by changing the number of sheets of printing medium P that will not be judged as defective even if floating is detected based on the thickness of the printing medium P, it is possible to both reduce the user's workload for defective judgment and prevent damage to the line head 31.

[0063] Furthermore, for example, when the size of the printing medium P is large, the length of the printing medium P in the direction perpendicular to the transport direction (front-to-back direction) is longer than the length of each line head 31 in the perpendicular direction. When the size of the printing medium P is large like this, even if warping occurs at both ends of the printing medium P in the perpendicular direction (ends extending in the transport direction), the warping is outside the installation range of the line head 31, so the printing medium P will not collide with the line head 31 and will be transported without any problems.

[0064] Therefore, if the size of the printing medium P is equal to or larger than a predetermined size (for example, A3 size), the judgment unit 61 may not judge that there is a transport failure from the start of supply of the printing medium P for a specified print job, regardless of the detection result of the floating detection unit 70.

[0065] This reduces unnecessary stops of the inkjet printing apparatus 1 and reduces the workload on the user in response to a determination error.

[0066] Furthermore, in the above embodiment, the transport failure judgment control is performed for the multiple paper feed units (side paper feed unit 10, internal paper feed unit 20) provided in the inkjet printing device 1 without distinguishing between them, but the transport failure judgment control of the present invention may be performed only when using the side paper feed unit 10 (manual feed tray), which is prone to paper floating.

[0067] The following additional notes are further disclosed regarding the transport failure determination device of the present invention. (Addendum)

[0068] In the transport failure determination device of the present invention, the determination unit can change the preset number of sheets at which a transport failure is not determined even if floating of the printing medium is detected, based on the attribute information of the printing medium.

[0069] In addition, in the transport failure determination device of the present invention, the determination unit can switch between a first determination method, based on attribute information of the printing medium, in which a transport failure is not determined even if floating of the printing medium is detected until a predetermined number of sheets have been supplied, and a second determination method in which a transport failure is determined if floating is detected from the time the printing medium starts to be supplied from the supply unit.

[0070] Furthermore, in the conveyance failure determination device of the present invention, the determination unit can switch to the second determination method when the attribute information is information indicating that the print medium has a predetermined hardness or more.

[0071] Furthermore, in the conveyance failure determination device of the present invention, the determination unit can switch to the second determination method when the attribute information is information indicating that the print medium has a predetermined thickness or more.

[0072] In addition, in the transport failure determination device of the present invention, if the attribute information indicates that the printing medium is larger than a predetermined size, the determination unit can not determine that there is a transport failure even if floating of the printing medium is detected from the start of supply of the printing medium from the supply unit.

[0073] A printing device of the present invention includes the defective determination device of the present invention, a supply unit, and a printing unit. [Explanation of symbols]

[0074] 1. Inkjet printing device 10 Side paper feed section 11 Paper feed stand 12 Primary paper feed section 14 Secondary paper feed section 14a Registration roller 20 Internal paper feed section 21a,21b,21c Paper feed stand 22a, 22b, 22c Primary paper feed section 30 Printing Department 31 Line Head 32 conveyor belt 33 First belt platen roller 34 Second belt platen roller 40 Paper output section 41 Paper receiving tray 42 Paper ejection roller 43 Switching mechanism 50 Reversal section 51 Inversion Table 52 Reversing roller 53 Conveyor roller 60 Control Unit 61 Judgment section 70 Floating detection unit 70a Swinging part 70b Vibration sensor section 70c support shaft CR Circulation Path FR paper feed path SR Reverse transport path P Print media

Claims

1. a lifting detection unit that is provided between a printing unit that performs a printing process on a print medium and a supply unit that supplies the print medium to the printing unit, and that detects lifting of the print medium supplied from the supply unit; a determination unit that determines whether the print medium is being conveyed properly based on the detection result by the lift detection unit, A transport failure determination device in which the determination unit does not determine that a transport failure has occurred even if floating of the printing medium is detected from the time the supply unit starts to supply the printing medium until a predetermined number of sheets have been supplied, and from the time the next sheet of printing medium after the predetermined number has been supplied, determines that a transport failure has occurred if floating of the printing medium is detected, and changes the predetermined number of sheets based on attribute information of the printing medium.

2. a lifting detection unit that is provided between a printing unit that performs a printing process on a print medium and a supply unit that supplies the print medium to the printing unit, and that detects lifting of the print medium supplied from the supply unit; a determination unit that determines whether the print medium is being conveyed properly based on the detection result by the lift detection unit, The determining unit does not determine that a transport failure has occurred even if floating of the printing medium is detected from the start of supply of the printing medium from the supply unit until a preset number of sheets have been supplied, and determines that a transport failure has occurred if floating of the printing medium is detected from the time the next preset number of sheets of printing medium has been supplied, and A transport failure determination device that switches between a first determination method that does not determine a transport failure even if floating of the printing medium is detected until the predetermined number of sheets has been supplied, and a second determination method that determines a transport failure if floating of the printing medium is detected from the time the supply of the printing medium from the supply unit begins, based on attribute information of the printing medium.

3. 3. The conveyance failure determination device according to claim 2, wherein the determination unit switches to the second determination method when the attribute information indicates that the print medium has a predetermined hardness or more.

4. 3. The conveyance failure determination device according to claim 2, wherein the determination unit switches to the second determination method when the attribute information indicates that the print medium has a predetermined thickness or more.

5. a lifting detection unit that is provided between a printing unit that performs a printing process on a print medium and a supply unit that supplies the print medium to the printing unit, and that detects lifting of the print medium supplied from the supply unit; a determination unit that determines whether the print medium is being conveyed properly based on the detection result by the lift detection unit, If the print medium is smaller than a predetermined size based on the attribute information of the print medium, the determination unit does not determine that a transport error has occurred even if the lift detection unit detects that the print medium has lifted from the time the supply unit starts to supply the print medium until a predetermined number of sheets have been supplied, and determines that a transport error has occurred if the lift of the print medium is detected from the time the next of the predetermined number of sheets of print medium has been supplied, A transport failure determination device that does not determine a transport failure even if floating of the printing medium is detected from the start of supply of the printing medium from the supply unit if the printing medium is a printing medium of a predetermined size or larger.

6. A printing apparatus comprising the conveyance failure determination device according to claim 1 , the supply unit, and the printing unit.

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