JP4886336B2 - Image forming apparatus, sheet conveyance control method, and sheet conveyance control program - Google Patents

Description

  The present invention relates to image forming processing, and more particularly to sheet conveyance control in an image forming apparatus capable of performing image forming processing on both sides of a sheet using an ADU.

  In recent years, with the improvement in performance of image forming apparatuses, the types of print media handled have been diversified. Examples of such various printing media include thick (large basis weight) paper and slippery coated paper. In a conventional image forming apparatus, the conveyance speed is optimized for each of these print media to realize good conveyance performance and print image quality. Switching the transport speed in this way means switching the processing speed of the electrophotographic process together.

Generally, in double-sided printing using a stackless ADU (Auto Duplex Unit), when printing paper is a short size, a method of performing so-called alternating circulation so as not to reduce the processing efficiency of image forming processing as much as possible is adopted. (See, for example, Patent Documents 1 to 3.) In alternate circulation, after securing a path length that can hold two or more short-sized printing sheets in the ADU and performing “first-in” for drawing two sheets from a paper source (paper cassette, etc.) ( (The number of first-in sheets can be 3 sheets or 4 sheets depending on the ADU path length, and can be 3 sheets or 4 sheets), and alternately for sheets conveyed from the ADU and sheets conveyed from the paper source. Print.
JP 2002-337417 A JP 2005-99197 A JP-A-10-167542

  Generally, a certain amount of switching time is required to switch the process speed in the process unit.

  Usually, in sheet conveyance control in the image forming apparatus, the sheet conveyance path is divided into several drive blocks. For example, when a sheet is transported in the ADU with a single motor, only one sheet transport speed can be realized in the ADU. Therefore, the transport speed of the next print medium is different until the print medium in the ADU is empty. Cannot be switched.

  In order to change the process speed, it is necessary to complete the formation of the image to be formed in the process unit. Therefore, when a long process path length such as a quadruple tandem is used, the image formation on the next page is not performed. You will have to wait for a long time. Further, when the rotation speed of the polygon motor is adjusted in accordance with the conveyance speed, it is necessary to wait until the rotation is stabilized, and here again, a waiting time for the next page occurs.

  FIG. 7 shows a case where double-sided printing is performed in a conventional image forming apparatus when two sheets of plain paper and two sheets of thick paper are fed in this order (printing in the order of pages 2 → 4 → 1 → 6 → 3 → 8 → 5 → 7). It is a figure which shows the flow of sheet conveyance. In the figure, thick paper is drawn with a solid line thicker than plain paper. The sheet feeding order here is plain paper (0), plain paper (1), thick paper (2), and thick paper (3).

  After the plain paper (0) is fed (FIG. 7 (a)), an image is formed on the back surface, and is switched back to the ADU (FIG. 7 (b)). Subsequently, plain paper (1) is fed, and after an image is formed on the back side of the paper, it is conveyed back to the ADU. At the same time, the plain paper (0) transported in the ADU is transported again to the process unit, and an image is formed on the front surface (FIG. 7 (c)).

  Thereafter, the plain paper (0) is discharged, and the plain paper (1) is carried into the ADU. Then, since the thick paper (2) is fed next to the plain paper (1), the image forming apparatus having different process speeds for the plain paper and the thick paper needs to switch to the process speed for the thick paper here. (FIG. 7D).

  Further, even after the image formation on the back surface of the thick paper (2) is completed, since it is the plain paper (1) that is next transported to the process unit, it is necessary to switch the process speed again. Since it takes time to switch the process speed, the plain paper (1) must wait for the process speed switching process to be completed at the exit position of the ADU. Further, while the plain paper (1) is waiting at the ADU exit position, the subsequent cardboard (2) cannot completely enter the ADU, so that the sheet process waiting at the ADU exit position is performed. Similarly, it is necessary to wait at the ADU entrance position until the transfer to the unit is started (FIG. 7E).

  Thereafter, the plain paper (1) is discharged, and the thick paper (3) is conveyed toward the process unit (FIG. 7 (f)). Subsequently, the cardboard (2) carried into the ADU is conveyed to the process unit, and the cardboard (3) is carried into the ADU that has been switched back (FIG. 7 (g)).

  The cardboard (2) that has undergone the process processing is discharged, and then the cardboard (3) is conveyed toward the process unit (FIG. 7 (h)). Then, the cardboard (3) on which the image is formed is discharged and the processing is completed (FIG. 7 (i)).

  When performing sheet conveyance control as shown in FIG. 7, generally, in an in-body discharge type image forming apparatus, the vicinity of the entrance of the ADU is often located above the fixing unit because of the sheet conveyance path. The cardboard (2) waiting at the ADU entrance position is exposed to the heat for a long time (see FIG. 7 (e)). As a result, the moisture of the cardboard (2) is excessively evaporated and the toner transferability is deteriorated, and the transfer failure due to the fact that the toner hardly adheres when forming an image on the front surface of the cardboard (2). And the image quality of the image formed on the thick paper (2) may be deteriorated.

  The present invention has been made to solve the above-described problems, and contributes to improvement of image quality in an image forming apparatus that performs image forming processing on both sides of a sheet using ADU and elimination of problems in image forming processing. It aims at providing the technology which can do.

In order to solve the above-described problem, the display control method according to the present invention is an image forming apparatus that can perform image forming processing on both sides of a sheet using ADU. Then, the second sheet in the paper feed cassette and the first sheet in the ADU having an image formed on one side thereof are alternately supplied to the process unit in the order of the second sheet and the first sheet. In the case of the second sheet, the sheet is conveyed from the inside of the paper feed cassette, and in the case of the first sheet, the sheet is conveyed from the ADU, and the image forming means alternately transfers the second sheet and the first sheet. When transported to a process unit, the process unit is placed after the second sheet relative to the process speed of the process unit for the second sheet that passes through the process unit first. You must change the process speed of the process unit with respect to said first sheet over to, the need to the first sheet for the process of switching the process speed in the process unit is waiting for a predetermined time or more in the ADU and whether the determined standby necessity determining unit there at the standby necessity determining unit, when the first sheet is judged that it is necessary to wait a predetermined time within the ADU, the first Without transporting the second sheet and the first sheet to the process unit alternately in the order of the second sheet and the first sheet, the second sheet, the first sheet, and the first sheet. characterized in that from the ADU formed by a pre-Symbol conveyance control unit from the paper feed cassette you fed toward the process unit from the conveyed toward the process unit Than is.

A sheet conveyance control method according to the present invention is a sheet conveyance control method in an image forming apparatus capable of performing image forming processing on both sides of a sheet using an ADU, and is a second sheet in a sheet feeding cassette. And the first sheet in the ADU having an image formed on one side thereof in turn in the order of the second sheet and the first sheet, and in the case of the second sheet, the sheet feeding cassette. From the inside, in the case of the first sheet, it is a sheet conveyance control method for conveying from within the ADU, and the sheet conveyance control method conveys the second sheet and the first sheet alternately to the process unit. The process unit after the second sheet with respect to the process speed of the process unit for the second sheet passing through the process unit first. You must change the process speed of the process unit with respect to the first sheet to pass through the Tsu bets, waiting for the first sheet a predetermined time or more in the ADU for switching processing of the process speed in the process unit a standby necessity determination step of determining whether it is necessary to, the stands by necessity determination step, when the first sheet is judged that it is necessary to wait a predetermined time within the ADU is The second sheet and the first sheet are not conveyed alternately to the process unit in the order of the second sheet and the first sheet, and the second sheet is transferred to the first sheet. a conveyance control step you supplied toward from said paper feed cassette to the process unit sheets from the conveyed from within the ADU to the process unit It is characterized in that the Ete made.

A sheet conveyance control program according to the present invention is a sheet conveyance control in an image forming apparatus capable of performing image forming processing on both sides of a sheet using an ADU, and includes a second sheet in a sheet cassette. The first sheet in the ADU having an image formed on one side thereof is alternately transferred to the process unit in the order of the second sheet and the first sheet, and in the case of the second sheet, in the sheet feeding cassette. In the case of the first sheet, a sheet conveyance control program for causing a computer to execute sheet conveyance control for conveying from within the ADU , wherein the second sheet and the first sheet are alternately transferred to the process unit. When the sheet is conveyed, the second speed of the process unit with respect to the process speed of the second sheet that has passed through the process unit first is determined. You must change the process speed of the process unit with respect to the first sheet passing through the process unit after the bets, the first sheet in the ADU for switching processing of the process speed in the process unit In the standby necessity determination step for determining whether or not it is necessary to wait for a predetermined time or more and the standby necessity determination step, it is determined that the first sheet needs to wait in the ADU for a predetermined time. In this case, the second sheet and the first sheet are not conveyed alternately to the process unit in the order of the second sheet and the first sheet. fed toward the process unit from the paper feed cassette the first sheet from the conveyed toward the process unit from within the ADU It is characterized in that to execute a conveyance control step that the computer.

  As described above in detail, according to the present invention, a technique that can contribute to improvement of image quality in an image forming apparatus that performs image forming processing on both sides of a sheet using ADU and elimination of defects in image forming processing. Can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an outline of a configuration of an image forming apparatus 1 according to the present embodiment. The image forming apparatus 1 according to the present embodiment is a color quadruple tandem machine.

  In the image forming apparatus 1 according to the present embodiment, a laser beam from the laser scan unit 95 is scanned on the photosensitive drum 94 by a polygon mirror to form an electrostatic latent image, and toner is attached to the electrostatic latent image. The electrostatic latent image is visualized with a toner image. Subsequently, the toner image formed on the photosensitive drum 94 as described above is primarily transferred onto the belt surface of the intermediate transfer belt 92 by the primary transfer roller 93. The quadruple tandem machine has a laser scanning unit (LSU) for four colors and an electrophotographic process.

  The intermediate transfer belt 92 continues to rotate, and the primary transferred image is supplied (paper fed) from the paper feed cassette 96 to the sheet conveyance path, and the secondary transfer roller is applied to the printing medium (sheet) whose timing is adjusted by the registration roller 90. Second transfer is performed by 99. Next, the print medium onto which the toner image has been transferred is conveyed to a fixing device 97, where the toner image is heated and fixed. Accordingly, the conveyance speed of the print medium needs to match the rotation speed of the intermediate transfer belt, and the intermediate transfer belt matches the polygon scanning speed.

  The print medium that has passed through the fixing device 97 is reversed near the discharge port and is carried into an automatic duplex unit (ADU) 98. The path length in the ADU 98 is set to a length that can accommodate a sheet of A3 / LD longitudinal size. When transporting in the longitudinal direction of A4 / LT, one more sheet (two in total) should be carried into the ADU 98. Is possible.

  FIG. 2 is a diagram showing a drive system in the image forming apparatus 1 according to the present embodiment. The image forming apparatus 1 according to the present embodiment includes a paper feed drive system M1 that feeds a print medium from a paper feed cassette 96 and conveys it to a registration roller 90, an LSU drive system M2 that drives a polygon that operates a laser, and an intermediate A transfer / fixing drive system M3 that forms an image on the transfer belt 92 and conveys the print medium from the registration roller 90 to transfer and fix, and a paper discharge reversal drive system that reversely conveys the print medium to be discharged or carried into the ADU 98. M5 and an ADU drive system M4 that conveys one or two print media into the ADU 98 and sends them to the registration roller 90 again.

  In the ADU 98, three rollers that are rotationally driven by one ADU drive system motor M4 are provided. In the ADU 98, the uppermost first roller R1 is rotationally driven by the ADU drive system motor M4, and the second roller R2 and the third roller R3 are rotationally driven by turning on the electromagnetic clutch, thereby being carried into the ADU. Even if the interval between the media is wide, it is possible to carry out alternate circulation by inserting two sheets.

  The image forming apparatus 1 according to the present embodiment has a plurality of paper feeding devices (a paper feeding device from a plurality of paper feeding cassettes, a paper feeding device from a manual feed position, etc.), and different types of printing such as plain paper and thick paper. Media can be set. When printing on plain paper, it is transported and printed at the maximum performance that the printer engine can produce. When printing on thick paper, the conveyance speed is slowed down, and even with a stiff medium, fixing / conveyance is ensured without generating a large conveyance noise or jam. The image forming apparatus 1 also reduces the rotation speed of the polygon motor, the rotation speed of the intermediate transfer belt, and the rotation speed of each drive motor in the ADU when the conveyance speed (that is, the process speed) is reduced as described above.

  FIG. 3 is a functional block diagram for explaining the image forming apparatus according to the present embodiment. An image forming apparatus 1 according to the present embodiment is configured by, for example, an MFP (Multi Function Peripheral), and can perform image forming processing on both sides of a sheet using ADU. Specifically, the image forming apparatus 1 according to the present embodiment includes a standby necessity determination unit 101, a conveyance control unit 102, a CPU 103, and a MEMORY 104.

  The standby necessity determination unit 101 forms the first toner image on the first sheet to be conveyed from the ADU to the process unit (processing unit that forms a toner image on the sheet). It is determined whether it is necessary to wait for a predetermined time or longer in the ADU. Here, the “predetermined time” is set to a time when the first sheet is made to wait at the exit position of the ADU and the fixing property of the subsequent second sheet starts to be affected. It is desirable. Further, when the first sheet is made to stand by at the exit position of the ADU, a time during which the first sheet and the second sheet are not simultaneously positioned in the ADU (for example, the second sheet is fed). It is also possible to set the “predetermined time” to “the time from when the paper is fed to when conveyance by the ADU is started”.

  Hereinafter, specific examples of functions of the standby necessity determination unit 101 will be described. The standby necessity determination unit 101 changes the process speed in the process unit (one before the first sheet) to form a toner image on the first sheet to be conveyed from the ADU toward the process unit. Change from the process speed set for the preceding sheet conveyed to the process unit) and the process speed in the process unit to form a toner image on the first sheet. When it is determined that the change of the first sheet is necessary, it is determined that the first sheet needs to wait for a predetermined time or longer in the ADU.

  In addition, the standby necessity determination unit 101 changes the process speed in the process unit for forming the toner image on the first sheet from the first process speed, which is slower than the first process speed. In the case of changing to the process speed, it is determined that the first sheet needs to wait for a predetermined time or longer in the ADU. When decelerating the process speed, the time required to stabilize the rotational speed of the polygon mirror is longer than when increasing the process speed, so the time for waiting the first sheet in the ADU is longer.

  The standby necessity determination unit 101 also determines the type of the first sheet and the preceding sheet conveyed to the process unit immediately before the first sheet, and sets the type of each of the first sheet and the preceding sheet. If the associated process speeds are different, it may be determined that the first sheet needs to wait for a predetermined time or longer in the ADU.

  The standby necessity determination unit 101 also determines whether the image to be formed on the first sheet and the preceding sheet conveyed to the process unit immediately before the first sheet is color or monochrome. If the color types of the images to be formed on the first sheet and the preceding sheet are different from each other, it is determined that the first sheet needs to wait in the ADU for a predetermined time or more. . As described above, when the color type of the image formed on the sheet is changed, time is required for preparation such as movement of the transfer roller, so that the time for waiting the first sheet in the ADU is long.

  Further, the standby necessity determination unit 101 needs to correct the toner image forming position in the process unit in order to form a toner image on the first sheet to be conveyed from the ADU toward the process unit. If it is determined that correction processing is necessary, it is determined that the first sheet needs to wait for a predetermined time or longer in the ADU.

  The standby necessity determination unit 101 determines whether it is necessary to wait the first sheet in the ADU for a predetermined time or longer by forming a toner image on the first sheet every time determination processing is performed. It is possible to calculate and determine how much time is required for the preparation for image forming, but it is necessary in advance for the correction processing of the sheet type, the color type of the image to be formed on the sheet, and the toner image forming position. The time may be stored in a predetermined storage area (for example, MEMORY 104) and the determination may be performed based on the stored required time.

  The standby necessity determination unit 101 is based on the image data used for the image forming process in the image forming apparatus 1, the operation input from the user to the image forming apparatus 1, the setting information stored in the MEMORY 104, and the like as described above. Judgment processing is performed.

  When the conveyance control unit 102 determines that the standby necessity determination unit 101 needs to wait for a predetermined time in the ADU in order to form a toner image on the first sheet In addition, the second sheet to be supplied to the sheet conveyance path following the first sheet is supplied after the first sheet is conveyed from the ADU toward the process unit.

  The CPU 103 has a role of performing various processes in the image forming apparatus 1 and also has a role of realizing various functions by executing a program stored in the memory MEMORY 104. The MEMORY 104 includes, for example, a ROM, a RAM, and the like, and has a role of storing various information and programs used in the image forming apparatus 1.

  FIG. 4 is a flowchart for explaining the flow of processing (image forming method) in the image forming apparatus 1 according to this embodiment.

  The standby necessity determination unit 101 needs to wait the first sheet in the ADU for a predetermined time or more in order to form a toner image on the first sheet to be conveyed from the ADU toward the process unit. It is determined whether or not there is (standby necessity determination step) (S101).

  When the conveyance control unit 102 determines in the standby necessity determination step that the first sheet needs to wait for a predetermined time in the ADU in order to form a toner image on the first sheet. Then, the second sheet to be supplied to the sheet conveyance path subsequent to the first sheet is supplied after the first sheet is conveyed from the ADU to the process unit (conveyance control step) (S102). .

  The standby necessity determination step determines whether or not it is necessary to change the process speed in the process unit in order to form a toner image on the first sheet to be conveyed from the ADU toward the process unit. When it is determined that the process speed in the process unit needs to be changed in order to form a toner image on the first sheet, the first sheet needs to wait in the ADU for a predetermined time or longer. judge. In the standby necessity determination step, the second process speed change in the process unit for forming the toner image on the first sheet is slower than the first process speed from the first process speed. If it is a change to the process speed, it is determined that the first sheet needs to wait in the ADU for a predetermined time or more.

  Further, the standby necessity determination step determines the type of the first sheet and the preceding sheet conveyed to the process unit immediately before the first sheet, and corresponds to each type of the first sheet and the preceding sheet. If the attached process speed is different, it can also be determined that the first sheet needs to wait in the ADU for a predetermined time or more. In the standby necessity determination step, the image to be formed on the first sheet and the preceding sheet conveyed to the process unit immediately before the first sheet is in either color or monochrome color type. If the color type of the image to be formed differs between the first sheet and the preceding sheet, it is determined that the first sheet needs to wait in the ADU for a predetermined time or more. You may do it. In addition, the standby necessity determination step requires correction processing of the toner image formation position in the process unit in order to form a toner image on the first sheet to be conveyed from the ADU toward the process unit. When it is determined that correction processing is necessary, it can be determined that the first sheet needs to be kept in the ADU for a predetermined time or more.

  Each step in the processing in the image forming apparatus 1 described above is realized by causing the CPU 103 to execute a sheet conveyance control program stored in the MEMORY 104.

  FIG. 5 shows a sheet in double-sided printing in the image forming apparatus according to the present embodiment when two sheets of plain paper and two sheets of thick paper are supplied in this order (1 to 4 pages are plain paper and 5 to 8 pages are thick paper). It is a figure which shows the flow of conveyance. In the figure, thick paper is drawn with a solid line thicker than plain paper. The sheet feeding order here is plain paper (0), plain paper (1), thick paper (2), and thick paper (3).

  In this embodiment, before the third sheet whose transport speed is switched is fed from the sheet feeding device, the second sheet in the ADU is first sent to the transfer and fixing drive system, and the third page is printed. When the second sheet passes through the transfer fixing driving system, the transfer speed of the transfer fixing driving system is switched for the third sheet, and the third sheet is pulled from the registration roller to perform printing. The print page order is 2 → 4 → 1 → 3 → 6 → 8 → 5 → 7. Details of sheet conveyance control in the present embodiment will be described below. 5 (A) to 5 (C) are the same as the prior arts already described (FIG. 7 (A) to FIG. 7 (C)), and the description thereof will be omitted.

  The plain paper (0) is discharged, and the plain paper (1) is carried into the ADU. Here, it is the thick paper (2) that is fed next to the plain paper (1), but the process speed is different between the plain paper and the thick paper in the image forming apparatus 1 according to the present embodiment. Prior to the sheet feeding, the plain paper (1) in the ADU is transported to the process unit first (FIG. 5D). As a result, the sheet in the ADU becomes empty, and the sheet following the plain paper (1) can be accommodated in the ADU. In this way, when a predetermined preparation time is required to form an image of the first sheet to be conveyed from the ADU to the process unit, the second sheet is fed before the subsequent second sheet is fed. In addition, by conveying the first sheet, it is possible to solve the problem of image quality degradation that has been a problem in the conventional sheet conveyance control. FIG. 6 is a diagram comparing the image quality of each print page when the conventional sheet conveyance control is performed and the print page when the sheet conveyance control according to the present embodiment is performed. As shown in the figure, in the conventional sheet conveyance control, the image quality of the “fifth page printed on thick paper” highlighted in black is poor, and in the sheet conveyance control according to the present embodiment, there is a problem with the same page. Does not occur.

  Then, the plain paper (1) on which the image is formed is discharged and the thick paper (2) is fed (FIG. 5 (E)). Subsequently, the cardboard (2) with the image formed on the back surface is switched back and carried into the ADU, and the cardboard (3) is fed (FIG. 5 (F)). The cardboard (2) carried into the ADU is conveyed again toward the process unit in order to form an image on its front surface. The cardboard (3) on which the image is formed on the back side is switchback conveyed and carried into the ADU (FIG. 5G).

  Subsequently, the cardboard (2) on which the image is formed is discharged, and then the cardboard (3) is conveyed toward the process unit (FIG. 5 (H)). Then, the cardboard (3) on which the image is formed is discharged and the processing is completed (FIG. 5 (I)).

  In this embodiment, the function for implementing the invention is recorded in advance in the apparatus. However, the present invention is not limited to this, and the same function may be downloaded from the network to the apparatus, and the same function is recorded. What is stored in the medium may be installed in the apparatus. The recording medium may be any form as long as the recording medium can store the program and can be read by the apparatus, such as a CD-ROM. Further, the function obtained by installing or downloading in advance may be realized in cooperation with an OS (operating system) or the like inside the apparatus.

  As described above, according to the present exemplary embodiment, it is possible to realize good sheet conveyance performance in the image forming apparatus and to maintain print image quality. It is also possible to deal with a case where a plurality of different process speeds are provided depending on the type of print medium. Further, the technique according to the present embodiment is particularly effective when the sheet carry-in port to the ADU is located in the vicinity of the upper part of the fixing device for heating and fixing the toner image on the sheet.

  Although the present invention has been described in detail according to particular embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

1 is a configuration diagram showing an outline of a configuration of an image forming apparatus 1 according to the present embodiment. 2 is a diagram showing a drive system in the image forming apparatus 1 according to the present embodiment. FIG. 2 is a functional block diagram for explaining an image forming apparatus according to the present embodiment. FIG. 4 is a flowchart for explaining a flow of processing (image forming method) in the image forming apparatus 1 according to the present embodiment. FIG. 6 is a diagram illustrating a flow of sheet conveyance during duplex printing when sheets are supplied in the order of two plain papers and two thick papers in the image forming apparatus according to the present embodiment. FIG. 10 is a diagram comparing the image quality of each print page when conventional sheet conveyance control is performed, and each print page when sheet conveyance control according to the present embodiment is performed. FIG. 10 is a diagram illustrating a flow of sheet conveyance during double-sided printing when sheets are fed in the order of two plain papers and two thick papers in a conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus, 101 Standby necessity determination part, 102 Conveyance control part, 103 CPU, 104 MEMORY.

Claims (11)

An image forming apparatus capable of performing image forming processing on both sides of a sheet by using an ADU, a second sheet in a paper feed cassette, and a first sheet in the ADU on which an image is formed on one side Are alternately conveyed to the process unit in the order of the second sheet and the first sheet, from the inside of the paper feed cassette in the case of the second sheet, and from the inside of the ADU in the case of the first sheet. ,
The image forming apparatus includes:
When the second sheet and the first sheet are alternately conveyed to the process unit, the second sheet with respect to the process speed of the process unit with respect to the second sheet that has passed through the process unit first. After that, it is necessary to change the process speed of the process unit with respect to the first sheet passing through the process unit, and the first sheet is set in the ADU for the process speed switching process in the process unit. A standby necessity determination unit that determines whether or not it is necessary to wait for a time or longer, and
At the standby necessity determining unit, wherein when the first sheet is judged that it is necessary to wait a predetermined time within the ADU, the second sheet and the first sheet of the second without the transported to the process unit alternately sheet and the order of the first sheet, the second sheet, before the first sheet from the conveyed toward the process unit from within the ADU image forming apparatus of serial paper feed cassette comprising a conveyance control unit fed toward the process unit. The image forming apparatus according to claim 1.
The standby necessity determination unit is configured to change a process speed in the process unit for forming a toner image on the first sheet from a first process speed lower than the first process speed. An image forming apparatus that determines that the first sheet needs to wait in the ADU for a predetermined time or more when the process speed is changed. The image forming apparatus according to claim 1.
The standby necessity determination unit determines the type of the first sheet and the preceding sheet conveyed to the process unit immediately before the first sheet, and the type of each of the first sheet and the preceding sheet An image forming apparatus that determines that the first sheet needs to wait in the ADU for a predetermined time or more when the process speeds associated with the ADU are different. The image forming apparatus according to claim 1.
The standby necessity determination unit determines whether an image to be formed on the first sheet and a preceding sheet conveyed to the process unit immediately before the first sheet is color or monochrome. When the color types of images to be formed on the first sheet and the preceding sheet are different from each other, the first sheet needs to wait in the ADU for a predetermined time or more. An image forming apparatus that determines that The image forming apparatus according to claim 1.
The standby necessity determination unit needs to correct a toner image forming position in the process unit in order to form a toner image on the first sheet to be conveyed from the ADU toward the process unit. An image forming apparatus that determines whether it is necessary to wait for a predetermined time or more in the ADU when it is determined that correction processing is necessary. A sheet conveyance control method in an image forming apparatus capable of performing image forming processing on both sides of a sheet using an ADU, comprising: a second sheet in a paper feed cassette; and an image formed on the one side of the ADU. The first sheet and the second sheet and the first sheet alternately in the process unit, in the case of the second sheet from the inside of the paper feed cassette, in the case of the first sheet A sheet conveyance control method for conveying from within an ADU,
The sheet conveyance control method includes:
When the second sheet and the first sheet are alternately conveyed to the process unit, the second sheet with respect to the process speed of the process unit with respect to the second sheet that has passed through the process unit first. After that, it is necessary to change the process speed of the process unit with respect to the first sheet passing through the process unit, and the first sheet is set in the ADU for the process speed switching process in the process unit. A standby necessity determination step for determining whether or not it is necessary to wait for more than an hour; and
At the standby necessity determination step, when said first sheet is judged that it is necessary to wait a predetermined time within the ADU, the second sheet and the first sheet of the second wherein without the transported to the process unit alternately sheet and the order of the first sheet, the second sheet, the first sheet from the conveyed toward the process unit from within the ADU sheet conveyance control method from the paper feed cassette comprising a conveyance control step you fed toward the process unit. In the sheet conveyance control method according to claim 6,
In the standby necessity determination step, a second process speed change in the process unit for forming a toner image on the first sheet is slower than the first process speed from the first process speed. A sheet conveyance control method for determining that the first sheet needs to wait for a predetermined time or more in the ADU when the process speed is changed. In the sheet conveyance control method according to claim 6,
The standby necessity determination step determines the type of the first sheet and the preceding sheet conveyed to the process unit immediately before the first sheet, and the type of each of the first sheet and the preceding sheet A sheet conveyance control method for determining that the first sheet needs to wait in the ADU for a predetermined time or longer when the process speeds associated with the ADU are different. In the sheet conveyance control method according to claim 6,
In the standby necessity determination step, an image to be formed on the first sheet and a preceding sheet conveyed to the process unit immediately before the first sheet is any color type of color and monochrome. When the color types of images to be formed on the first sheet and the preceding sheet are different from each other, the first sheet needs to wait in the ADU for a predetermined time or more. The sheet conveyance control method to determine that. In the sheet conveyance control method according to claim 6,
In the standby necessity determination step, a correction process of a toner image formation position in the process unit is required to form a toner image on the first sheet to be conveyed from the ADU toward the process unit. A sheet conveyance control method for determining whether or not the first sheet needs to wait for a predetermined time or more in the ADU when it is determined that correction processing is necessary. A sheet conveyance control in an image forming apparatus capable of performing image forming processing on both sides of a sheet using an ADU, the second sheet in a paper feed cassette, and the second sheet in the ADU in which an image is formed on one side. One sheet and the second sheet and the first sheet alternately in the order of the process unit, in the case of the second sheet, from within the paper feed cassette, and in the case of the first sheet, the ADU. A sheet conveyance control program for causing a computer to execute sheet conveyance control for conveying from the inside ,
When the second sheet and the first sheet are alternately conveyed to the process unit, the second sheet with respect to the process speed of the process unit with respect to the second sheet that has passed through the process unit first. After that, it is necessary to change the process speed of the process unit with respect to the first sheet passing through the process unit, and the first sheet is set in the ADU for the process speed switching process in the process unit. A standby necessity determination step for determining whether or not it is necessary to wait for more than an hour; and
At the standby necessity determination step, when said first sheet is judged that it is necessary to wait a predetermined time within the ADU, the second sheet and the first sheet of the second wherein without the transported to the process unit alternately sheet and the order of the first sheet, the second sheet, the first sheet from the conveyed toward the process unit from within the ADU sheet transport control program for executing a transfer control step from the paper feed cassette you fed toward the process unit to the computer.

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