JP2012133077A - Image forming device and print control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent printing failure such as a protrusion of a print image from a recording paper sheet from occurring in an image forming device.SOLUTION: An image forming device has: print size acquiring means 642 for acquiring a size of a print image; paper sheet size measuring means 644 conveying a recording paper sheet to a conveyance path so as to measure a size of the recording paper sheet; and printing control means 646 for controlling conveying operation and printing operation. When the size of the recording paper sheet is unknown, the paper sheet size measuring means 644 conveys the recording paper sheet to the conveyance path so as to measure the size of the recording paper sheet without performing printing operation thereof. When the size of the recording paper sheet measured by the paper sheet size measuring means 644 corresponds to the size of the print image acquired by the print size acquiring means 642 within a predetermined tolerance range, the printing control means performs image printing operation on the recording paper sheet.

Description

  The present invention relates to an image forming apparatus such as a copying machine and a printer, and a printing control method in the image forming apparatus.

  The image forming apparatus includes a plurality of paper feed trays containing recording papers of different sizes, and the size of the recording paper contained in each paper feed tray is detected by a sensor provided in each of the paper feed trays. For each print request, an appropriate paper feed tray corresponding to a designated paper size is selected to perform a printing operation.

  However, some image forming apparatuses do not have a sensor for detecting the paper size in the paper feed tray for the purpose of cost reduction. In such an image forming apparatus, the size of the conveyed recording paper ( Inconsistency between the (paper feed size) and the size of the print image (print size) may cause problems such as protrusion of the image from the recording paper (out of image).

  As a method for avoiding the size mismatch, there is known a method in which the user inputs the size of the recording paper stored in the paper feed tray to the image forming apparatus every time the paper feed tray is attached to the image forming apparatus. Yes. With this method, the image forming apparatus can select an appropriate paper feed tray according to the image size and execute printing. However, it is troublesome for the user to input, and an input error, forgetting input, etc. If there is a human error, a mismatch between the image size and the paper size cannot be avoided.

  Therefore, the image forming apparatus measures the passage time of the recording paper at the sensor position by a sensor for detecting the paper position provided in the recording paper conveyance path, and from the measured passage time and the conveyance speed of the recording paper, A method for calculating a length (hereinafter referred to as a paper feed length) in a conveyance direction (hereinafter referred to as a sub-scanning direction) of a recording sheet is known (see Patent Document 1). In this method, the length match between the recording paper and the print image in the direction orthogonal to the sub-scanning direction (main scanning direction) is unknown, but the length match in the sub-scanning direction can be confirmed. By performing printing after confirming the matching of the lengths, it is possible to greatly reduce the probability of occurrence of printing abnormality such as image breakage.

  Also, it has a double-sided printing function and uses a sensor provided in the transport path to measure the feed length when printing on the first side, and when a mismatch between the feed length and the print length is detected, There is known an image forming apparatus that discharges the recording paper directly or after passing through a conveyance path for backside printing depending on the position of the recording paper after one-side printing (Patent Document). 2).

  However, in the above conventional method, in order to detect the paper feed length, it is necessary to transport the recording sheet along the transport path in the image forming apparatus. Need to run. That is, in the above conventional method, the paper feed length cannot be known in advance, and if the paper feed length and the print length do not match (size mismatch) as a result of detecting the paper feed length, at least 1 is required. There is a problem of wasting one sheet of recording paper. In addition, the recording paper (abnormal paper) that has lost its image due to the size mismatch is discharged without being distinguished from other normally printed recording paper (normal paper). There is also a problem that it takes time to sort.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to reduce the probability of occurrence of printing abnormality such as protrusion of a print image without wasting recording paper in an image forming apparatus. It is.

The present invention relates to a print size acquisition unit that acquires the size of a print image, a sheet conveyance measuring unit that conveys a recording sheet to a conveyance path and measures the size of the recording sheet, and a print control that controls a conveyance operation and a printing operation. The sheet conveyance measuring unit conveys the recording sheet to a conveyance path when the recording sheet size is unknown, measures the size of the recording sheet without performing printing, and The print control means prints an image on the recording paper when the size of the recording paper measured by the paper conveyance measuring means matches the print image size acquired by the print size acquisition means within a predetermined allowable range. An image forming apparatus.
The present invention also includes a print size acquisition unit that acquires the length of the print image in the sub-scanning direction, a sheet conveyance measurement unit that conveys the recording sheet to the conveyance path and measures the sub-scanning direction length of the recording sheet, A printing control unit that controls a conveyance operation and a printing operation. When the sub-scanning direction length of the recording sheet is unknown, the sheet conveyance measuring unit conveys the recording sheet to the conveyance path and performs printing. The printing control unit measures the length of the recording paper in the sub-scanning direction without performing the printing, and the printing size acquisition unit acquires the printing paper length measurement unit measured in the sub-scanning direction length of the recording paper. When the length of the image in the sub-scanning direction matches within a predetermined allowable range, the image forming apparatus performs image printing on the recording paper.
The present invention also relates to a printing control method in an image forming apparatus, a size acquisition step for acquiring a size of a print image, and a conveyance / measurement step for measuring the size of the recording paper by conveying the recording paper to a conveyance path. And a control process for controlling the transport operation and the printing operation. In the transport / measurement process, when the size of the recording paper is unknown, the recording paper is transported to the transport path for printing. When the size of the recording paper is measured, and the size of the recording paper measured in the conveyance / measurement step matches the size of the print image acquired in the size acquisition step within a predetermined allowable range. This is a printing control method for printing an image on the recording paper.

  According to the present invention, in an image forming apparatus that does not have a paper size detection function in a paper feed tray, the length of the recording paper in the sub-scanning direction is detected without wasting the recording paper, and the print image protrudes. It is possible to prevent printing abnormalities such as.

1 is a block diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. It is a block diagram which shows the structure of the image printing part shown in FIG. It is a block diagram which shows the structure of the control part shown in FIG. FIG. 5 is a flowchart showing an operation procedure of the image forming apparatus according to the embodiment of the present invention. FIG. 5 is a flowchart showing a procedure of a paper feed size measurement process shown in FIG. 4. It is a flowchart which shows the procedure of the abnormality process shown in FIG.4 and FIG.5.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention.
The image processing apparatus 1 receives a print request from an image printing unit 2 that prints an image on a recording sheet and a client PC (Personal Computer) via a network or the like, and based on image data included in the print request. A control unit 60 that causes the image printing unit 2 to perform a printing operation, and an operation unit for a user to input an instruction or data to the image forming apparatus 1, and the control unit 60 performs data or operation on the user. And an operation display unit 4 using a touch panel or the like, which is also a display means for displaying buttons and the like.

FIG. 2 is a configuration diagram of the image printing unit 2.
The image printing unit 2 is provided for each of a plurality of paper feed trays 6 storing recording paper and the paper feed trays 6, and feeds the recording paper from the paper feed tray 6 to a printing path X indicated by a thick solid line in FIG. A paper roller 8, registration rollers 10 and 12, and a paper position sensor 14 for detecting a recording paper entering the registration rollers 10 and 12 are provided. Here, the registration rollers 10 and 12 have a function of determining the conveyance timing of the recording paper for image transfer from the intermediate transfer belt 44 described later to the recording paper, and the recording is performed by temporarily stopping the registration rollers 10 and 12. It also has a function of correcting the inclination of the recording paper by abutting the paper.

  In addition, the image printing unit 2 fixes the image by heating the transfer paper 16 that transfers an image formed on an intermediate transfer belt 44 described later to the recording paper that has passed through the registration rollers 10 and 12 and the recording paper. Fixing rollers 18 and 20, guide rollers 22, 24, 26 and 28 for guiding the recording sheet after image fixing to a discharge path Y indicated by a dotted line in FIG. 2 or a circulation path Z indicated by a one-dot chain line in FIG. , A guide roller 30 for conveying the recording paper, a plurality of paper discharge trays 32 for storing the recording paper conveyed through the discharge path Y, and a recording paper provided for each of the paper discharge trays 32 and guided to the discharge path Y And a paper discharge roller 34 for guiding the paper to each paper discharge tray 32.

  Here, the guide rollers 22 to 28 can guide the conveyance direction of the recording paper that has entered the discharge path Y from the print path X to the circulation path Z during double-sided printing. In this circulation path Z, guide rollers 36, 38, and 40 for guiding the recording paper are arranged, and the recording paper that has entered the circulation path Z is conveyed to the back surface printing standby position W to start the back surface printing. Wait. Further, the circulation path Z also includes a paper feed roller 42 that feeds the recording paper at the back surface printing standby position W to the printing path X.

  The main image printing unit 2 further includes C (cyan), M (magenta), and Y on the intermediate transfer belt 44, belt rollers 46 and 48 that rotate the intermediate transfer belt 44, and the intermediate transfer belt 44, respectively. It has four photoreceptor units 50 that form (yellow) and K (black) images, and a light source 52. The photoconductor unit 50 develops the photoconductor drum 502 on which an electrostatic latent image is formed by the light beam emitted from the light source 52 and the electrostatic latent image on the photoconductor drum 502 with toner. A developing unit 504 for forming a toner image is provided.

  On the intermediate transfer belt 44, the toner images of the respective colors formed on the surfaces of the photosensitive drums 502 of the four photosensitive units 50 are sequentially transferred to form one color image. When passing between the transfer belt 44 and the transfer roller 16, it is transferred onto the recording paper.

FIG. 3 is a block diagram illustrating a configuration of the control unit 60.
The control unit 60 includes a communication interface 62 that receives a print request from a client PC or the like via a network or the like, and a processing unit 64 that processes the print request received by the communication interface 62 and causes the image printing unit 2 to perform a printing operation. A storage unit 66 that stores information (size information) on the length (paper feed length) of the recording paper stored in each paper feed tray 6 in the sub-scanning direction measured by a paper size measuring unit 644 described later. is doing.

  The processing unit 64 is a computer having a CPU (Central Processing Unit), a ROM (Read Only Memory) in which a program is written, a RAM (Random Access Memory) for temporarily storing data, and the like via a network or the like. The print size acquisition means 642 for acquiring the length (print length) of the print image in the sub-scanning direction from the image data included in the print request received from the client PC or the like, and the passage of the recording paper measured by the paper position sensor 14 From the time t and the conveyance speed v of the recording paper (more strictly speaking, the average value of the linear velocity of the recording paper along the print path X at the position of the paper position sensor 14), for example, the recording paper feed length is ( The paper size measuring unit 644 which is a paper transport measuring unit and the recording paper transporting operation and the printing operation in the image printing unit 2 are measured. Print control means 646.

Here, instead of acquiring the print length of the print image from the image data, the print size acquisition unit 642 acquires the length of the print sheet in the sub-scanning direction as the print length from the designation of the print sheet in the received print request. It is good also as what to do.
Further, the recording paper conveyance speed v used when the paper size measuring unit 644 calculates the paper feed length can be measured in advance in the image forming apparatus 1 and given to the paper size measuring unit 644.

  Further, the sensor used by the paper size measuring unit 644 to measure the passage time of the recording paper is not necessarily a sensor provided upstream of the registration rollers 10 and 12 in the printing path X, like the paper position sensor 14. However, any sensor provided at a position along the print path may be used.

  Each means described above is a function realizing means of the processing unit (computer) 64 realized by a program. The computer program can be stored in any computer-readable storage medium.

  When the image forming apparatus 1 having the above configuration receives a print request from a client PC or the like via a network or the like, the image forming apparatus 1 refers to the size information in the storage unit 66 and uses the size information of the recording paper stored in the paper feed tray 6. When there is no information on the paper feed length, that is, when the paper feed length is unknown, the recording paper is fed from the paper feed tray 6 to the printing path X, and the paper size is measured without performing image printing on the recording paper. After measuring the passage time of the recording paper at the position of the paper position sensor 14 by means 644 and calculating the feed length of the recording paper, the recording paper is guided to the circulation path Z and conveyed to the backside printing standby position. . Then, the print length acquired by the print size acquisition unit 642 is compared with the paper feed length calculated above, and according to the comparison result, the processing of the recording paper conveyed to the backside print standby position is determined, Eject and print recording paper.

  That is, the recording paper used for the measurement of the feed length is not printed and is transported to the backside printing standby position as a blank sheet, and the recording paper is subjected to a comparison result between the feed length and the print length. Desired processing (discharge and printing) can be executed. For this reason, it is possible to prevent printing without knowing the size of the recording paper, and to prevent occurrence of printing abnormality such as image cutout due to mismatch between the paper feed size and the print size.

  In addition, since the recording paper is held at the back standby position as a white paper, when the recording paper is discharged, the discharged recording paper can be used for other printing operations. It can be used without waste.

Next, the operation procedure of the image forming apparatus 1 will be described with reference to the flowchart of FIG.
First, when the user turns on the power of the image forming apparatus 1 (S101), the processing unit 64 of the control unit 60 initializes the size information stored in the storage unit 66 to an unknown size state (S102). This initialization can be performed, for example, by writing a code indicating unknown size in the storage unit 66.

  Next, the processing unit 64 confirms reception of the print request from the client PC or the like via the network or the like by the communication interface 62 (S103), and the image of the print image included in the print request by the print size acquisition unit 642. After obtaining the length (printing length) of the print image in the sub-scanning direction from the data (S104), referring to the size information stored in the storage unit 66 (S105), a recording paper suitable for the printing length is obtained. It is determined whether there is an accommodated paper feed tray 6 (S106).

  Here, in step S104, instead of acquiring the print length of the print image, the print size acquisition unit 642 uses the print sheet length in the received print request as the print length from the designation of the print sheet. It can also be acquired.

  Further, in step S106, whether or not there is a paper feed tray 6 containing a recording paper suitable for the print length is determined by, for example, each paper feed tray 6 indicated in the size information stored in the storage unit 66. The sub-scanning direction length (paper feed length) of the recording paper to be stored is compared with the print length, and if the value of the paper feed length is within a predetermined allowable error range with respect to the print length, a record suitable for the print length It can be determined that there is a paper feed tray 6 containing paper. The predetermined allowable error range can be determined in advance for each print length and described in a program executed by the processing unit 64, which is a computer.

  Next, when there is a paper feed tray 6 containing a recording paper suitable for the print length (S106, Yes), the processing unit 64 feeds the recording paper from the paper feed tray 6 suitable for the print length. Printing is performed (S107), and the process returns to step S103 and is repeated.

  On the other hand, when there is no paper feed tray 6 containing recording paper that matches the print length (No in S106), it is determined whether there is a paper feed tray 6 with an unknown recording paper feed length. If there is an unknown tray (S108, Yes), the paper feed size measurement process is performed (S109). If there is no unknown tray, the current paper feed tray 6 matches the print length. Since the recording paper is not accommodated, an abnormal process is performed (S110).

After the paper feed size measurement process in step S109 or the abnormality process in step S110, the process returns to step S103 and the process is repeated.
Note that the processing shown in FIG. 4 ends when the image forming apparatus 1 is turned off.

Next, the procedure of the paper feed size measurement process (step S109) shown in the flowchart of FIG. 4 will be described according to the flowchart shown in FIG.
When the paper feed size measurement process is started, first, the paper size measuring unit 644 of the processing unit 64 selects one paper feed tray 6 whose recording paper feed length is unknown (S201), and the print control unit 646. Thus, the recording paper is fed from the selected paper feed tray 6 and printing is performed, that is, the image is not formed on the intermediate transfer belt 44 by the photosensitive unit 50, and the recording paper is fed to the printing path X. (S202), the paper size measuring means 644 measures the length of the recording paper in the sub-scanning direction (paper feed length) (S203).

  Here, since the image is not transferred onto the recording paper when the recording paper is conveyed in step S202, it is not necessary to fix the transferred image onto the recording paper. For this reason, it is desirable that the heating control is not performed on the fixing rollers 18 and 20, or the target temperature is set lower than the fixing temperature. As a result, power consumption can be reduced, and warping (curling) of the recording paper due to unnecessary heating can be prevented.

  Next, the paper size measurement unit 644 stores the paper feed length measured in step S203 and the identification code of the paper feed tray 6 that is the paper feed source of the recording paper in the storage unit 66 as size information (S204). Then, the recording paper is guided to the circulation path Z and conveyed to the back surface printing standby position W (S205).

  Subsequently, the print control unit 646 of the processing unit 64 determines whether or not the measured paper feed length is suitable for the print length (S206), and if it is suitable (S206, Yes), the back surface printing standby position W is determined. Is fed to the printing path X (S207), an image is printed on the recording sheet, and the paper is ejected to one of the paper ejection trays 32 (S208), and the paper feed size measurement process is terminated. .

  Here, whether or not the paper feed length matches the print length is determined when the paper feed length is within a predetermined allowable error range with respect to the print length, as in the method in step S106 of FIG. It can be determined that the paper length matches the print length.

  On the other hand, when the paper feed length does not match the print length in step S206 (S206, No), the print control unit 646 operates an instruction input screen for the user to instruct the processing unit 64 about the recording paper processing method. This is displayed on the display unit 4 (S209). Here, the user performs printing by discharging the recording paper used for measuring the paper feed length (paper discharge instruction) or changing the image size according to the paper feed length of the recording paper used for the measurement. (Print size change instruction) can be entered on the instruction input screen.

  Next, the print control unit 646 determines whether or not a print size change instruction has been input (S210). If a print size change instruction has been input (S210, Yes), the print length matches the paper feed length. As described above, after the image data is subjected to image processing (rotation, enlargement, reduction, etc.) to change the size of the print image (S211), the process proceeds to step S207 to print the recording sheet conveyed to the back surface printing standby position W. The process proceeds to the path X (S207), prints on the recording paper (S208), and finishes the paper feed size measurement process.

  Here, after the print size change instruction is input in step S210, when the paper is continuously fed from the paper feed tray 6 and printing is performed for the print request, the subsequent recording paper is also fed. A print image whose size is changed in accordance with the length can be printed.

  On the other hand, when the print size change instruction is not input in step S210 (S210, No), it means that the paper discharge instruction is input, and the recording paper transported to the back surface printing standby position W is printed with the print path X. Is discharged from the paper discharge path Y (S212), it is determined whether there is another paper feed tray 6 whose recording paper feed length is unknown (S213). If so (S213, Yes), the process returns to step S201 to repeat the process.

  Here, since the recording paper discharged in step S212 is a blank recording paper that has not been printed, if the recording paper is returned to the paper supply tray 6 that is the paper supply source, there is no waste as printing paper. Can be used. Further, when the recording paper is discharged, any one of the paper discharge trays 32 may be set in advance as the discharge destination. As a result, the recording paper (measurement paper) used to measure the paper feed length is discharged to a paper discharge tray 32 different from the recording paper (normal paper) that has been printed normally, so that the measurement paper is normal. Sorting work with paper can be made unnecessary. The designation of the paper discharge tray 32 to be used can be stored in advance in the storage unit 66 or the like of the control unit 60 by the user using the operation display unit 4, for example.

  On the other hand, if there is no paper feed tray 6 whose recording paper feed length is unknown in step S213 (No in S213), it means that there is no paper feed tray 6 that matches the print length, so that an abnormal process is performed. (S214), the paper feed size measurement process is terminated.

  Next, the procedure of the abnormality process (step S110 in FIG. 4 and step S214 in FIG. 5) shown in the flowchart of FIG. 4 and the flowchart of FIG. 5 will be described according to the flowchart shown in FIG.

  When the abnormal process is started, the processing unit 64 displays an instruction input screen on the operation display unit 4 together with an error message indicating that no recording paper suitable for the print length is stored in any currently installed paper feed tray 6. It is displayed (S301). On the other hand, the user inputs an instruction to stop printing (print stop instruction) or replaces one of the paper feed trays 6 with a paper feed tray 6 containing recording paper that matches the print length. Thereafter, an instruction to continue printing (tray replacement continuation instruction) can be input.

  Next, the processing unit 64 determines whether or not a print cancel instruction is input (S302). When the print cancel instruction is input (S302, Yes), the recording sheet conveyed to the back surface print standby position W is determined. Then, the paper is discharged from the paper discharge path Y via the print path X (S303), and the abnormality process is terminated.

  On the other hand, if no print cancel instruction is input in step S302 (No in S302), the user has attached a paper feed tray 6 containing recording paper that matches the print length, and has input a tray replacement continuation instruction. Therefore, the abnormality process is terminated as it is. Thereby, the process is repeated from step S103 of FIG.

  As described above, in the present embodiment, the recording paper used for the measurement of the paper feed length is input from the operation display unit 4 after being printed and not being printed and being kept at the back surface printing standby position W as a blank paper. According to the instruction, a print image having a size suitable for the paper feed length is printed or discharged and reused. For this reason, it is possible to prevent the occurrence of printing abnormality such as an image protruding from the recording paper, and the recording paper used for measuring the paper feed length is reused as a recording paper again without being wasted. be able to.

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Image printing part, 4 ... Operation display part, 6 ... Paper feed tray, 8, 42 ... Paper feed roller, 10, 12 ... Registration roller , 14 ... paper position sensor, 16 ... transfer roller, 18 ... fixing roller, 22, 24, 26, 28, 30, 36, 38, 40 ... guide roller, 32 ... paper discharge Tray, 34 ... discharge roller, 44 ... intermediate transfer belt, 46, 48 ... belt roller, 50 ... photoconductor unit, 52 ... light source, 60 ... control unit, 62. ..Communication interface, 64 ... Processing unit, 66 ... Storage unit, 502 ... Photosensitive drum, 504 ... Developing unit, 642 ... Print size acquisition means, 644 ... Paper size measurement Means, 646... Print control means.

JP-A-8-179777 JP 2007-065411 A

Claims (8)

Print size acquisition means for acquiring the size of the print image;
A paper transport measuring means for transporting the recording paper to the transport path and measuring the size of the recording paper;
Print control means for controlling the transport operation and the print operation;
Have
The paper conveyance measuring means, when the size of the recording paper is unknown, conveys the recording paper to the conveyance path, measures the size of the recording paper without performing printing,
The print control means prints an image on the recording paper when the size of the recording paper measured by the paper conveyance measuring means matches the print image size obtained by the print size obtaining means within a predetermined allowable range. An image forming apparatus to perform. Print size acquisition means for acquiring the length of the print image in the sub-scanning direction;
A paper conveyance measuring means for conveying the recording paper to the conveyance path and measuring the length of the recording paper in the sub-scanning direction;
Print control means for controlling the transport operation and the print operation;
Have
When the sub-scanning direction length of the recording paper is unknown, the paper transport measuring unit transports the recording paper to the transport path, measures the sub-scanning direction length of the recording paper without performing printing,
The printing control means, when the sub-scanning direction length of the recording paper measured by the paper conveyance measuring means coincides with the sub-scanning direction length of the print image obtained by the print size obtaining means within a predetermined allowable range, An image forming apparatus for printing an image on the recording paper. The image forming apparatus according to claim 2,
It has a circulation path that guides the recording paper that has passed through the transport path to the transport path again.
The paper conveyance measuring means conveys the recording paper whose length in the sub-scanning direction is measured to the circulation path,
The image forming apparatus that prints an image on a recording sheet conveyed to the circulation path. The image forming apparatus according to claim 3.
The print control means, when the sub-scanning direction length of the recording paper measured by the paper conveyance measuring means does not coincide with the sub-scanning direction length of the print image obtained by the print size obtaining means within a predetermined allowable range, Image formation in which the size of the print image is changed so that the sub-scanning direction length of the print image matches the measured sub-scanning direction length of the recording paper, and printing is performed on the recording paper conveyed to the circulation path apparatus. The image forming apparatus according to claim 3.
The print control means, when the sub-scanning direction length of the recording paper measured by the paper conveyance measuring means does not coincide with the sub-scanning direction length of the print image obtained by the print size obtaining means within a predetermined allowable range, An image forming apparatus for discharging the recording sheet conveyed to the circulation path. The image forming apparatus according to claim 5.
When the recording paper transported to the circulation path is discharged, the printing control unit discharges the recording paper to a discharge location different from a discharge location of other recording paper on which an image is printed. The image forming apparatus according to any one of claims 1 to 6,
A paper position detecting means provided at a predetermined position along the transport path for detecting the arrival of the recording paper at the predetermined position;
The paper conveyance measuring means measures the passage time of the recording paper passing through the predetermined position by the paper position detection means, and determines the sub-recording paper from the passage time and the recording paper conveyance speed at the predetermined position. An image forming apparatus for measuring a length in a scanning direction. A printing control method in an image forming apparatus,
A size acquisition step for acquiring the size of the print image;
A transport / measurement process for transporting the recording paper to the transport path and measuring the size of the recording paper;
A control process for controlling the conveyance operation and the printing operation;
Have
In the transport / measurement step, when the size of the recording paper is unknown, the recording paper is transported to the transport path, and the size of the recording paper is measured without performing printing.
In the control step, when the size of the recording paper measured in the conveyance / measurement step matches the size of the print image acquired in the size acquisition step within a predetermined allowable range, printing for performing image printing on the recording paper Control method.

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