JP2012148842A - Printer and paper feeding method - Google Patents

Abstract

To reduce the manufacturing cost of a printer capable of continuous feeding without leaving excess cut paper in the paper feed path when printing is completed.
When executing a job for printing an image on a sheet of n sheets (n ≧ 2) and a conveyance unit that conveys a cut sheet from a stacking unit to an image forming unit along a conveyance path, nk ( k ≦ 1, 2,..., n−1) The succeeding cut sheet is removed from the stacking unit before the printing on the preceding cut sheet is completed until the first cut sheet reaches a predetermined position on the transport path. When the n-kth cut sheet reaches a predetermined position on the conveyance path, the conveyance unit stops conveyance of the subsequent cut sheet until printing on the preceding cut sheet is completed. When printing of the n-kth cut sheets is completed, conveyance of the cut sheets up to the nth sheet to the image forming unit and printing by the image forming unit are executed for each sheet. Control to complete the job by Printer equipped with, and.
[Selection] Figure 1

Description

  The present invention relates to a printer and a paper feeding method, and more particularly to continuous feeding of cut paper.

  Conventionally, a sub-scanning roller for transporting cut paper in the sub-scanning direction in order to change the position in the sub-scanning direction on the cut paper on which the colorant such as ink is fixed, and a stacking unit such as a paper feed cassette to the sub-scanning roller A printer having a paper feed roller for transporting cut paper is known. The sub-scanning rollers are provided on the upstream side and the downstream side of the fixing position of the color material, respectively. The paper feed roller is provided above the paper feed cassette and conveys the cut paper to the upstream side sub-scanning roller. When the cut sheet reaches the upstream side sub-scanning roller, the electric motor that rotates the paper feed roller is stopped until the cut sheet is discharged by the downstream side sub-scanning roller.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique for driving a paper feed roller to follow a cut sheet conveyed by a sub-scanning roller while the sub-scanning roller is rotating. As a result, the distance for transporting the next cut sheet to the position where the color material is fixed after the cut sheet is discharged by the downstream sub-scanning roller can be shortened, so the time required for printing a plurality of pages can be shortened. be able to. Feeding a cut sheet of the next page during printing of one page in this way is called continuous feeding.

JP 2008-44313 A

  By the way, if the paper is transported to the next cut sheet while the last page is printed, the cut sheet remains in the sheet feed path when the last page is printed. In order to prevent the cut sheet from remaining in the paper feed path when printing is completed, continuous paper feed must be stopped before printing of the final page is completed. However, in order to measure the timing to stop the continuous paper feed immediately before the extra cut paper is conveyed by the paper feed roller, the leading edge of the cut paper on the last page has arrived at the timing at which the continuous paper feed should be stopped. A sensor for detecting the leading edge of the cut sheet is required at the position. Normally, a printer has a sensor for detecting the position of the leading edge of the cut sheet in the vicinity of the position where the color material is fixed. However, if the paper feed path is long, this sensor and the timing for stopping continuous paper feed are measured. This also increases the manufacturing cost.

  The present invention has been created to solve such problems, and has an object to reduce the manufacturing cost of a printer that can continuously feed without leaving excess cut paper in the paper feed path when printing is completed. To do.

  (1) A printer for achieving the above object includes an image forming unit that prints an image on the cut sheet while conveying the cut sheet, a stacking unit that stacks the cut sheet, and the stacking unit to the image forming unit. When executing a job for printing an image on n (n ≧ 2) cut sheets and a transport unit that transports cut sheets along the transport path, n−k (k ≦ 1, 2,... N− 1) The next cut sheet is conveyed from the stacking unit by the conveyance unit before the printing on the preceding cut sheet is completed until the first cut sheet reaches a predetermined position on the conveyance path, and nk sheets When the cut sheet of the eye reaches the predetermined position on the transport path, the transport of the subsequent cut sheet by the transport unit is stopped until the printing on the preceding cut sheet is completed, and printing of the nk-th cut sheet is performed. When completed, n sheets by the transport unit Comprising a transport to the image forming portion of cut sheets up, and a control unit to complete the job by the printing by the image forming unit, executes one by one.

  According to the present invention, when a cut sheet one page or more before the last page reaches a predetermined position on the conveyance path, conveyance of the last page is stopped until printing of the cut sheet one page or more before the last page is completed. To do. That is, the continuous paper feeding is stopped when the cut sheet one page or more before the last page reaches a predetermined position. Therefore, even when the paper feed path from the stacking unit to the image forming unit is long, it is possible to measure the timing at which continuous paper feeding is stopped by the sensor provided in the image forming unit. Then, after the continuous sheet feeding is stopped, conveyance to the image forming unit and printing by the image forming unit are alternately performed for each cut sheet to complete printing up to the final page. For this reason, according to the present invention, it is possible to reduce the manufacturing cost of a printer capable of continuously feeding without leaving extra cut paper in the paper feed path when printing is completed.

(2) In the printer for achieving the above object, the printer includes a sensor for detecting the leading edge of the cut sheet at the predetermined position, and the control unit detects the leading edge of the nk-th cut sheet at the predetermined position. At that time, the conveyance of the cut sheet by the conveyance unit may be stopped until the printing of the nk-th cut sheet is completed.
That is, the continuous paper feed may be stopped when the leading edge of the cut paper is detected by a sensor provided at a predetermined position.

(3) The printer for achieving the above object includes a sensor for detecting a leading edge of the cut sheet in the image forming unit, and the control unit detects the leading edge of the (n−1) th cut sheet. When the n-th cut sheet is conveyed by a predetermined distance from the nth sheet, the conveyance of the n-th cut sheet by the conveyance unit may be stopped until the printing of the (n-1) th cut sheet is completed.
That is, continuous feeding may be stopped when the cut sheet is conveyed by a predetermined distance from when the leading edge of the cut sheet is detected by the sensor. In this case, since the distance for transporting the cut sheet to the position where the color material is fixed after stopping the continuous sheet feeding can be shortened, the time required for printing to the last page can be shortened.

  Note that the function of each means described in the claims is realized by hardware resources whose function is specified by the configuration itself, hardware resources whose function is specified by a program, or a combination thereof. Further, the functions of these means are not limited to those realized by hardware resources that are physically independent of each other. Furthermore, the present invention can be realized as a method, a computer program, and a recording medium for the program. Of course, the recording medium for the computer program may be a magnetic recording medium, a magneto-optical recording medium, or any recording medium that will be developed in the future.

It is a block diagram which shows a printer. 6 is a flowchart illustrating a paper feeding method. It is a state transition diagram showing a paper feeding method. It is a state transition diagram showing a paper feeding method. It is a state transition diagram showing a paper feeding method. 6 is a flowchart illustrating a paper feeding method. It is a state transition diagram showing a paper feeding method.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the corresponding component in each figure, and the overlapping description is abbreviate | omitted.
1. Configuration FIG. 1 shows a printer 1 as an embodiment of the present invention. The printer 1 is a serial inkjet printer that forms an image by fixing ink as a colorant on a cut sheet as a printing medium. Therefore, the printer 1 alternately stacks the cut sheet P, the image forming unit 10 that repeatedly carries the cut sheet conveyance in the sub-scanning direction and the image formation in the main scanning direction, the stacking unit 30 that loads the cut sheet P, and the like. A conveyance unit 20 that is taken out from the unit 30 and conveyed to the image forming unit 10 and a control unit 40 that controls the image forming unit 10 and the conveyance unit 20 are provided.

  The stacking unit 30 includes a first cassette 31 and a second cassette 32 on which cut sheets are stacked. Each of the first cassette 31 and the second cassette 32 is configured by a member for holding a plurality of stacked cut sheets P.

  The transport unit 20 includes relay rollers 21a and 21b, paper feed rollers 22 and 23, electric motors 26 and 24, motor drivers 45 and 46, a guide 25, and the like. The paper feed roller 22 is a roller for taking out the uppermost cut paper P from the first cassette 31 one by one. The paper feed roller 23 is a roller for taking out the uppermost cut paper P from the second cassette 32 one by one. The relay rollers 21a and 21b are rollers that convey the cut paper P taken out from the first cassette 31 or the second cassette 32 by the paper feed rollers 22 and 23 to a position where the sub-scanning rollers 17c and 17d can hold the cut paper P. The electric motor 24 rotates the paper feed roller 23. The motor driver 46 is a circuit that drives the electric motor 24. The electric motor 26 rotates the paper feed roller 22, the relay rollers 21 a and 22, and the sub-scanning rollers 17 b and 17 d of the image forming unit 10 at the same time. The guide 25 is a wall having a form for guiding the cut paper P conveyed by the relay rollers 21a and 21b and the paper feed rollers 22 and 23 to a position where the sub-scanning rollers 17c and 17d can be held. The motor driver 45 is a circuit that drives the electric motor 26.

  The conveyance path from the paper feed roller 23 to the relay roller 21a is shorter than the long side of A4 size. For this reason, the paper feed roller 23 is configured to idle by following the cut paper P when the A4 size cut paper is conveyed in the long side direction by the relay roller 21a. The transport path from the relay roller 21a to the sub-scanning roller 17d is shorter than the long side of A4 size. For this reason, the relay roller 21a is configured to idle and follow the cut sheet P when the A4-size cut sheet P is conveyed in the long side direction by the sub-scanning rollers 17b and 17d.

  The image forming unit 10 includes a recording head 11, an ink tank 12, a carriage 13, a guide 14, an endless belt 15, an electric motor 16, a motor driver 47, sub-scanning rollers 17a, 17b, 17c, and 17d, an electric motor 26, a platen 19, and the like. Is done. The recording head 11 includes a known mechanism such as a piezo method or a thermal method, and discharges ink from a nozzle to fix the cut paper P supplied from the first cassette 31 or the second cassette 32. The ink tank 12 is a container that stores ink supplied to the recording head 11 by color. The carriage 13 is a support member that reciprocates with the ink tank 12 and the recording head 11 mounted thereon. The guide 14 is a rod-shaped member that guides the movement of the carriage 13 in the main scanning direction. The endless belt 15 is stretched over a pulley (not shown) and pulls the carriage 13. The electric motor 16 rotates a pulley around which an endless belt 15 is stretched. The motor driver 47 is a circuit that drives the electric motor 16. The sub-scanning rollers 17a, 17b, 17c, and 17d convey the cut paper P taken out from the first cassette 31 or the second cassette 32 and conveyed by the relay rollers 21a and 21b in the sub-scanning direction. The platen 19 is a bar-like member that is provided directly below the recording head 11 and positions the cut paper P with respect to the recording head 11.

  The control unit 40 includes a CPU (Central Processing Unit), a main memory, a nonvolatile memory, an interface circuit, and the like (not shown). The non-volatile memory stores a control program for controlling the image forming unit 10 and the conveyance unit 20. The CPU is a processor that executes a control program loaded into the main memory.

  The paper detection sensor 18 is an optical sensor provided in the vicinity of the upstream side of the platen 19. The paper detection sensor 18 includes a light emitting unit and a light receiving unit (not shown), and detects that the leading edge of the cut paper has reached the optical path of the paper detection sensor 18 by blocking the optical path from the light emitting unit to the light receiving unit. To do. The length of the conveyance path from the paper feed roller 23 to the paper detection sensor 18 is longer than the long side of A4 and shorter than twice the long side of A4.

2. Paper Feeding Method Next, a flow chart shown in FIG. 2 and a state shown in FIGS. 3 to 5 show a paper feeding method when executing a print job for continuously forming images on a plurality of cut sheets loaded in the second cassette 32. This will be described based on the transition diagram. 3, 4, and 5 illustrate a process in which a print job for forming an image on three cut sheets P (1), P (2), and P (3) proceeds.

When acquiring the print job from the PC or the like, the control unit 40 acquires the number of printed sheets (n) from the print job (S100).
Next, the control unit 40 rotates the paper feed roller 23 and the relay roller 21a to convey the first cut paper to the paper detection sensor 18 (S102, S104). Specifically, the control unit 40 rotates the paper feed roller 23 and the relay roller 21a by a predetermined angle by the electric motors 24 and 22 until the output of the paper detection sensor 18 indicates the arrival of the leading edge of the cut paper. 3A, the first cut sheet P (1) is taken out from the uppermost part of the second cassette 32 by the paper feed roller 23 and cut by the relay roller 23 as shown in FIG. 3B. The leading edge of the paper P (1) reaches the optical path of the paper detection sensor 18 as shown in FIG. 3C.

When the leading edge of the cut sheet reaches the paper detection sensor 18, the control unit 40 determines whether the cut sheet detected by the paper detection sensor 18 is the (n-1) th sheet, that is, the cut on which the image of the page immediately before the last page is printed. It is determined whether it is paper (S106). Since the length of the transport path from the paper feed roller 23 to the paper detection sensor 18 is longer than the long side of A4 and shorter than twice the long side of A4, the leading edge of the (n-1) th cut paper is detected by the paper. When the sensor 18 is reached, the paper feed roller 23 has taken out the nth cut sheet. That is, determining whether the cut sheet detected by the paper detection sensor 18 is the (n−1) th sheet is determining whether the paper feed roller 23 is starting to convey the cut sheet of the last page.
Each time the paper detection sensor 18 detects the leading edge of the cut sheet, the control unit 40 starts image forming processing for one page by the image forming unit 10. That is, the control unit 40 drives the electric motor 26 based on the print job to convey the cut paper in the sub-scanning direction with the optical path of the paper detection sensor 18 as a reference position, and drives the electric motor 16 to perform the main scanning of the print head 11. Then, an image forming process is started in which the print head 11 is driven to eject ink droplets from the nozzles. The image forming process is started whenever the leading edge of the cut sheet reaches the position of the sheet detection sensor 18 as shown in FIGS. 3B, 4A, and 5B, and until the process for n pages is completed as shown in FIG. 5D. It is executed for each cut sheet.

  If the cut sheet whose leading edge is detected by the paper detection sensor 18 is not the (n−1) th sheet, the control unit 40 relays simultaneously with the sub-scanning rollers 17d and 17b until the leading edge of the (n−1) th sheet is detected. The roller 21a and the paper feed roller 23 are rotated (S107, S108, S106). Accordingly, while the image is formed on the preceding cut sheet by the image forming unit 10, the subsequent cut sheet is caused to follow the preceding cut sheet. That is, the paper feeding unit 20 takes out the succeeding cut sheet P (2) from the second cassette 32 before printing on the preceding cut sheet P (1) is completed as shown in FIGS. 3C, 3D, and 3E. To the image forming unit 10. At this time, the driving of the sub-scanning rollers 17d and 17b of the image forming unit 10 is executed alternately with the image formation in the main scanning direction, so that the cut sheet is conveyed by the sheet feeding unit 20 intermittently. The peripheral speed of the relay roller 21a driven by the electric motor 26 is slower than the peripheral speed of the sub-scanning rollers 17d and 17b, and the peripheral speed of the paper feed roller 23 driven by the electric motor 23 is lower than the peripheral speed of the relay roller 21a. Therefore, as shown in FIGS. 3C, 3D, and 3E, the interval between the preceding cut sheet P (1) and the subsequent cut sheet P (2) gradually increases. Specifically, the control unit 40 designates a rotation angle to the motor drivers 45 and 46 and rotates the motors 24 and 26 by a predetermined angle (S107). Next, the control unit 40 determines whether the leading edge of the cut sheet has reached the sheet detection sensor 18 (S108). When the leading edge of the cut sheet reaches the sheet detection sensor 18, the control unit 40 determines whether the reached cut sheet is the (n-1) th sheet (S106). Then, until the leading edge of the (n-1) th cut sheet reaches the sheet detection sensor 18, the control unit 40 rotates the motors 24, 26 by a predetermined angle while designating the rotation angle to the motor drivers 45, 46 (S107). .

  When the leading edge of the (n-1) th cut paper reaches the paper detection sensor 18, the control unit 40 stops the paper feed roller 23 until the (n-1) th cut paper is discharged by the downstream sub-scanning roller 17b. (S110). Specifically, as shown in FIG. 4A, when the leading edge of the cut sheet P (2) immediately before the last page reaches the optical path of the paper detection sensor 18, the cut sheet immediately before the last page is shown in FIG. 4C. The controller 40 stops the electric motor 24 until the image formation for P (2) is completed. As a result, the cut sheet P (3) of the last page remains in a state where the leading edge is located between the second second cassette 32 and the relay rollers 21a and 21b as shown in FIG. 4B.

  When the (n-1) th cut sheet is discharged by the downstream side sub-scanning roller 17b, the control unit 40 rotates the paper feed roller 23 and the relay roller 21a to remove the nth cut sheet from the paper detection sensor 18. (S112, S114). Specifically, as shown in FIGS. 5A and 5B, the control unit 40 drives the motors 26 and 24 to rotate the paper feed roller 23 and the relay roller 21a until the leading edge reaches the optical path of the paper detection sensor 18. The cut sheet P (3) is conveyed.

  When the nth cut sheet reaches the sheet detection sensor 18, the control unit 40 stops the sheet feeding roller 23 and ends the sheet feeding process (S114). Accordingly, as shown in FIGS. 5C and 5D, the n + 1th sheet of cut paper P (4) is not taken out from the second cassette 32, and the cut paper P (3) of the last page is transferred to the relay roller 21a and the sub-scanning roller. 17d and 17b and printing on the cut sheet P (3) is completed. As a result, execution of the print job is completed.

  According to the embodiment described above, when the leading edge of the (n-1) th cut sheet is detected in the optical path of the paper detection sensor 18, the cut sheet by the transport unit 20 is printed until the printing of the (n-1) th cut sheet is completed. Stop continuous feeding. For this reason, even if the transport path from the second cassette 32 to the paper detection sensor 18 provided in the path near the platen 19 that is the ink fixing position is longer than the long side of the A4 size, it is provided in the vicinity of the platen 19. The paper detection sensor 18 can measure the timing for stopping the continuous paper feeding. Accordingly, it is possible to measure the timing at which the continuous paper feeding is stopped by the single paper detection sensor 18 while obtaining the reference for the sub-scanning rollers 17d and 17b to accurately position the cut paper. That is, according to the present embodiment, in order to measure the timing for stopping the continuous paper feeding separately from the sensor for acquiring the reference for accurately positioning the cut paper by the sub-scanning rollers 17d and 17b in the image forming unit 10. Therefore, the construction of the printer 1 can be simplified and the manufacturing cost can be reduced. According to the present embodiment, the cut sheet is continuously fed until the leading edge of the cut sheet immediately before the last page is conveyed to the vicinity of the platen 19, so that the printing time can be shortened. After the continuous paper feed is stopped, only one cut sheet of the last page is fed after the printing of the page immediately before the last page is completed, so that an extra cut sheet remains in the paper feed path when printing is completed. There is nothing.

3. Other Embodiments The technical scope of the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the scope of the present invention.
For example, in the above embodiment, the continuous paper feeding is stopped when the leading edge of the cut sheet immediately before the last page is detected by the paper detection sensor 18, but the leading edge of the cut sheet immediately before the last page is detected by the paper detection sensor 18. The continuous feeding may be stopped after the sheet has been conveyed by a predetermined distance. For example, as shown in FIG. 6, after the leading edge of the (n-1) th cut paper reaches the paper detection sensor 18 (after "true" is determined in S106), the leading edge of the nth cut paper is the relay roller 21a. The paper feed roller 23 is rotated simultaneously with the sub-scanning rollers 17d and 17b until reaching (S1091, S1092). 7A, even if the leading edge of the (n-1) th cut sheet P (2) reaches the sheet detection sensor 18, continuous sheet feeding by the sheet feeding roller 23 is performed as illustrated in FIG. 7C. The process continues until the leading edge of the nth cut sheet P (3) reaches the relay roller 21a. That is, the continuous feeding is continued until the (n−1) th cut sheet is conveyed by a predetermined distance downstream from the sheet detection sensor 18 by the sub-scanning rollers 17 d and 17 b driven simultaneously with the sheet feeding roller 23. . During this time, as shown in FIG. 7B, the printing on the (n-1) th cut sheet P (2) is being performed while rotating the sub-scanning rollers 17d and 17b. The conveyance of P (3) is intermittent. When the leading edge of the nth cut sheet P (3) reaches the relay roller 21a, the n−1th cut sheet P (2) is discharged by the sub-scanning roller 17b as in the above embodiment. The paper feed roller 23 is stopped (S110). Thereafter, as in the above embodiment, printing is performed on the nth cut sheet P (3) as shown in FIGS. 7D, 7E, and 7F, and the print job is completed. Thus, the distance for transporting the nth cut sheet P (3) to the platen 19 after the (n-1) th cut sheet P (2) is discharged by the sub-scanning roller 17b is shorter than that in the above embodiment. Therefore, the printing time can be shortened.

  Further, for example, in the above-described embodiment, an example in which continuous feeding is stopped when the cut sheet of the page immediately before the last page reaches a predetermined position has been described. However, the conveyance path from the feeding roller 23 to the platen 19 is long, and the feeding roller In the case where the transport path from 23 to the paper detection sensor 19 provided in the vicinity of the platen 19 is also long, n−k (2 ≦ k <n−2) in a job for printing on n (n ≧ 4) sheets of cut paper The continuous feeding may be stopped when the first cut sheet reaches a predetermined position with the paper detection sensor 19 as a reference. For example, if the transport path from the paper feed roller 23 to the paper detection sensor 19 provided in the vicinity of the platen 19 is longer than twice the long side of A4 and shorter than 3 times, the n-2th cut sheet The continuous paper feeding may be stopped when the paper detection sensor 19 detects the leading edge.

  Further, for example, in the above-described embodiment, an example in which the present invention is applied to a serial type ink jet printer has been described. However, the present invention can also be applied to a line printer or a page printer using toner as a colorant.

  For example, in the above embodiment, the paper detection sensor is provided in the image forming unit. However, the paper detection sensor may be provided in the transport unit. Even when the paper detection sensor is provided in the transport unit, the number of sensors for paper detection can be reduced to one by providing the paper detection sensor downstream of the position where the paper feed path joins. The paper detection sensor is not limited to a non-contact type such as an optical sensor, but may be a contact type.

  Further, for example, in the above-described embodiment, the relay roller 21a provided between the paper feed roller 23 and the sub-scanning roller 17d is always driven simultaneously with the sub-scanning roller 17d. The roller 23 may always be driven simultaneously.

DESCRIPTION OF SYMBOLS 1 ... Printer, 10 ... Image forming part, 11 ... Recording head, 12 ... Ink tank, 13 ... Carriage, 14 ... Guide, 15 ... Endless belt, 16 ... Electric motor, 17a ... Sub scanning roller, 17b ... Sub scanning roller, 17c ... sub-scanning roller, 17d ... sub-scanning roller, 18 ... paper detection sensor, 19 ... platen, 20 ... conveying unit, 21a ... relay roller, 21b ... feed roller 22 ... feed roller, 23 ... feed roller, 24 ... Electric motor, 25 ... guide, 30 ... loading unit, 31 ... first cassette, 32 ... second cassette, 32 ... second cassette, 40 ... control unit, 45 ... motor driver, 46 ... motor driver, 47 ... motor driver

Claims (4)

An image forming unit for printing an image on the cut sheet while conveying the cut sheet;
A loading section for loading cut sheets;
A transport unit that transports cut sheets from the stacking unit to the image forming unit along a transport path;
When executing a job for printing an image on n (n ≧ 2) cut sheets, the n−k (k ≦ 1, 2,... n−1) th cut sheet is a predetermined position on the transport path. Until the printing on the preceding cut sheet is completed, the succeeding cut sheet is conveyed from the stacking unit by the conveying unit until the nk cut sheet reaches a predetermined position on the conveying path. Then, the conveyance of the subsequent cut sheet by the conveying unit is stopped until the printing on the preceding cut sheet is completed, and when the printing of the nk-th cut sheet is completed, the cut sheet up to the n-th sheet by the conveying unit is completed. A control unit that completes the job by executing conveyance to the image forming unit and printing by the image forming unit for each sheet;
Printer with. A sensor for detecting the leading edge of the cut sheet at the predetermined position;
The control unit stops the conveyance of the cut sheet by the conveyance unit until the printing of the n-kth cut sheet is completed when the leading edge of the nk-th cut sheet is detected at the predetermined position.
The printer according to claim 1. A sensor for detecting the leading edge of the cut sheet in the image forming unit;
The control unit completes printing of the (n-1) th cut sheet when the nth cut sheet is conveyed by a predetermined distance after the sensor detects the leading edge of the (n-1) th cut sheet. The conveyance of the nth cut sheet by the conveyance unit is stopped until
The printer according to claim 1. An image forming unit that prints an image on the cut sheet while conveying the cut sheet, a stacking unit that stacks the cut sheet, and a conveyance unit that conveys the cut sheet from the stacking unit to the image forming unit along a conveyance path; A paper feeding method in a printer comprising:
When executing a job for printing an image on n (n ≧ 2) cut sheets, the n−k (k ≦ 1, 2,... n−1) th cut sheet is a predetermined position on the transport path. Until the printing on the preceding cut sheet is completed, the succeeding cut sheet is conveyed from the stacking unit by the conveying unit until the nk cut sheet reaches a predetermined position on the conveying path. Then, the conveyance of the subsequent cut sheet by the conveying unit is stopped until the printing on the preceding cut sheet is completed, and when the printing of the nk-th cut sheet is completed, the cut sheet up to the n-th sheet by the conveying unit is completed. To complete the job by executing the conveyance to the image forming unit and the printing by the image forming unit for each sheet.
Paper feeding method.

Images