JP2018155948A - Image forming apparatus and image forming program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that absorbs a speed difference between a transfer speed and a fixing speed and reduces the influence on an image compared with a case where the image forming apparatus includes a single suction conveyance device, and an image forming program.SOLUTION: An image forming apparatus, when a sheet longer than the length between a second transfer roller and a fixing part is set, detects the leading end of the sheet with a registration sensor 24, and subsequently measures the timing at which the leading end of the sheet reaches a fixing part with a counter. When the timing at which the leading end of the sheet reaches the fixing part is reached, a control device performs control of reducing a suction force of or stops suction performed by at least one or more suction conveyance devices, of a plurality of suction conveyance devices, other than a suction conveyance device on a transfer side.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image forming apparatus and an image forming program.

  Patent Document 1 discloses a loop detection device that detects a loop formed on a sheet between a secondary transfer device and a fixing device, and sheet conveyance between the secondary transfer device and the fixing device based on a detection signal of the loop detection device. There has been proposed an image forming apparatus including a control unit that controls a speed difference and adjusts a sheet loop amount.

  In Patent Document 2, a fan is driven to convey a sheet while adsorbing it to an endless belt, and when the first sensor and the second sensor detect the floating of the sheet, the amount of suction by the fan is increased. A sheet conveying apparatus that facilitates adsorption is proposed.

JP 2014-44232 A JP 2006-176265 A

  In a configuration including a single suction conveyance device, if the suction force of the suction conveyance device is reduced or suction is stopped to absorb the speed difference between the transfer speed and the fixing speed, the posture of the recording medium during transfer changes. The image quality can be affected. SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus and an image forming program that suppress an influence on an image while absorbing a speed difference between a transfer speed and a fixing speed as compared with a case where a single suction conveyance apparatus is provided. To do.

  The image forming apparatus according to claim 1, wherein the transfer direction of the recording medium is between a transfer unit that transfers the image to the recording medium and a fixing unit that fixes the image transferred by the transfer unit to the recording medium. And a plurality of suction conveyance units that convey the recording medium while sucking the recording medium, and the recording medium having a length equal to or longer than the distance between the transfer unit and the fixing unit is conveyed, and the leading end is And a control unit that performs suction control for reducing suction force or stopping suction of at least one suction conveyance unit provided outside the transfer unit side when the fixing unit is reached.

  According to a second aspect of the present invention, in the first aspect of the present invention, there are provided three or more suction conveyance units, and the control unit is configured as the suction control other than both ends in the conveyance direction among the plurality of suction conveyance units. Performs control to reduce the suction force of the provided suction conveyance unit or stop suction

  According to a third aspect of the present invention, in the first aspect of the present invention, when the control unit lowers the suction force of the plurality of suction conveyance units or stops the suction, the recording medium is transported downstream in the conveyance direction. The suction force is reduced or the suction is stopped in order from the suction transport unit on the side.

  According to a fourth aspect of the present invention, in the first aspect of the invention, when the control unit lowers the suction force of the plurality of suction conveyance units or stops the suction, the recording medium is transported upstream. The suction force is reduced or the suction is stopped in order from the suction transport unit on the side.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the control unit is configured to reduce the suction force of the suction conveyance unit as the recording medium is thinner. Further control the suction force.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects of the present invention, the plurality of suction conveyance units are disposed below the apparatus along a straight line connecting the transfer unit and the fixing unit. In addition, the movement trajectory when the recording medium is conveyed along a plurality of suction conveyance units is arranged so as to draw a downward convex curve.

  An image forming program according to a seventh aspect causes a computer to function as a control unit of the image forming apparatus according to any one of the first to sixth aspects.

  According to the first aspect of the present invention, it is possible to provide an image forming apparatus capable of suppressing the influence on the image while absorbing the speed difference between the transfer speed and the fixing speed as compared with the case where a single suction conveyance apparatus is provided. .

  According to the second aspect of the present invention, the posture of the recording medium at the time of transfer and the posture of the recording medium at the time of fixing can be stabilized as compared with the case where a single suction conveyance device is provided.

  According to the third aspect of the present invention, the absorption of the speed difference when the fixing speed is slower than the transfer speed is compared with the case where the suction force is reduced or the suction is stopped in order from the upstream side in the conveyance direction of the recording medium. It can be done smoothly.

  According to the fourth aspect of the present invention, it is possible to suppress the contact of the sheet with the fixing unit housing or the like even when the sheet is loosened as compared with the case where the single suction conveyance device is provided.

  According to the fifth aspect of the present invention, the fluttering of the recording medium and the occurrence of wrinkles can be suppressed as compared with the case where the suction force is controlled to be constant regardless of the thickness of the recording medium.

  According to the sixth aspect of the present invention, it is possible to suppress the occurrence of wrinkling and folding of the sheet as compared with the case where the suction conveyance unit is arranged so as to draw a convex downward linearly.

  According to the seventh aspect of the present invention, it is possible to provide an image forming program capable of suppressing the influence on the image while absorbing the speed difference between the transfer speed and the fixing speed as compared with a case where a single suction conveyance device is provided. .

1 is a side view illustrating a schematic configuration of an image forming apparatus according to an exemplary embodiment. (A) is a perspective view which shows a suction conveyance apparatus, (B) is a side view which shows schematic structure of several suction conveyance apparatus. FIG. 2 is a block diagram illustrating a main configuration of a control system of the image forming apparatus according to the present embodiment. (A) is a side view showing an example of the state of a sheet when the suction force of two suction conveyance devices other than the transfer side suction conveyance device is reduced or the suction is stopped, and (B) is a transfer side suction conveyance device. FIG. 10 is a side view showing an example of a state of a sheet when the suction force of the suction transport device at the center other than the above is reduced or suction is stopped and the suction force of the suction transport device on the fixing unit side is maintained. 6 is a flowchart illustrating an example of a flow of processing performed by the control device of the image forming apparatus according to the present exemplary embodiment. 10 is a flowchart illustrating a modification of the flow of processing performed by the control device of the image forming apparatus according to the present exemplary embodiment.

  Hereinafter, the present embodiment will be described with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus 10 according to the present embodiment.

  The image forming apparatus 10 according to the present embodiment forms an image on a sheet P as a recording medium by an electrophotographic method. Specifically, as shown in FIG. 1, in the image forming apparatus 10, an intermediate transfer belt 40 formed of an endless belt is supported by a plurality of rolls 42 with a predetermined tension. Further, on the intermediate transfer belt 40, along the belt running direction X, image recording units 44C, 44M, corresponding to each color of cyan (C), magenta (M), yellow (Y), and black (K), 44Y and 44K are arranged in this order. In the following description, unless otherwise distinguished, each image recording unit has the same configuration, and therefore, the description corresponding to each color including the respective units constituting the image forming unit will be omitted.

  Each of the image recording units 44 includes a photosensitive drum 46 whose shaft is rotatably fixed to an apparatus main body frame (not shown). Around each photosensitive drum 46, along a drum rotation direction (clockwise direction in FIG. 1), a cleaner 48, an erase lamp (not shown), a charger 50, a laser scanning device 12, a developing device 52, and The primary transfer rolls 54 are arranged in order.

  That is, the residual toner on the photosensitive drum 46 is removed by the cleaner 48, the charge on the photosensitive drum 46 is removed by the erase lamp for static elimination, and charged by the charger 50, and the photosensitive drum 46 is charged by the laser scanning device 12. The surface of the substrate is irradiated with light to form a latent image. The latent image formed by the laser scanning device 12 forms a toner image by the developing device 52 and is transferred to the intermediate transfer belt 40 by the primary transfer roll 54. Note that sub-scanning is performed by each photosensitive drum 46, and main scanning is performed by the laser scanning device 12.

  On the other hand, paper P as a recording medium to be image-recorded is accommodated in a paper feeding unit (not shown). A plurality of types of paper P are stored in the paper feeding unit, and are fed one by one by a pickup roll 56 provided on the paper feeding side of the paper feeding unit. The fed paper P is conveyed by a predetermined number of roll pairs 58 along a path indicated by a broken line in the drawing, and is sent to a pressure contact position of a secondary transfer roll 60 as an example of a transfer unit. The color image on the intermediate transfer belt 40 is collectively transferred (secondary transfer) onto the paper P by the transfer roll 60. The sheet P on which the color image has been transferred is conveyed to the fixing unit 64 by a plurality of (three in this embodiment) suction conveyance devices 26, 28, and 30 as an example of a suction conveyance unit, where the image fixing process (heating) is performed. , Pressurization, etc.), and then discharged to a discharge portion (not shown).

  The suction conveyance devices 26, 28, and 30 are arranged below the apparatus from the straight line (second dashed line in FIG. 1) connecting the secondary transfer roll 60 and the fixing unit 64, and the paper P is loaded into each suction conveyance device 26, 28, 30. Is arranged so as to draw a convex curve downward. As a result, the slack of the paper P is formed between the secondary transfer roll 60 and the fixing unit 64, and the difference between the transfer speed and the fixing speed is absorbed. Further, by arranging each suction conveyance device 26, 28, 30 so as to draw a convex curve (for example, a parabola) downward, each suction conveyance device 26, 28, 30 so as to draw a convex downward linearly. The occurrence of wrinkles and creases in the paper P is suppressed compared to the case where the paper is arranged.

  Here, an example of the configuration of the plurality of suction conveyance devices 26, 28, and 30 will be described. 2A is a perspective view showing the suction conveyance devices 26, 28, and 30, and FIG. 2B is a side view showing a schematic configuration of the plurality of suction conveyance devices 26, 28, and 30. Note that the configuration of the suction conveyance devices 26, 28, and 30 shown in FIG. 2 is an example, and is not limited to this configuration, and a suction conveyance device having another configuration may be applied.

  As shown in FIGS. 2A and 2B, each of the suction conveyance devices 26, 28, and 30 is U-shaped when viewed from the conveyance direction (a shape in which the upper side and both sides in the conveyance direction are open). A driving roll 72 and a driven roll 74 that are rotatably driven with their shaft ends supported by the casing 70 (FIG. 7B), and a plurality of belt members 76 wound around the driving roll 72 and the driven roll 74. ,have. Although not shown, the gaps between the plurality of belt members 76 are sealed by providing guide members.

  Further, as shown in FIG. 2B, a fan unit 78 having a suction fan 79 is provided inside the belt member 76 and is fixed to the housing 70 of the suction conveyance devices 26, 28, 30.

  As shown in FIG. 2A, each belt member 76 has a plurality of through holes 76A. Therefore, by driving the suction fan 79 of the fan unit 78 shown in FIG. 2B, air is sucked into the belt member 76 from the through hole 76A.

  With such a configuration, each of the suction conveyance devices 26, 28, and 30 sucks the paper P onto the upper surface 76 </ b> B of the belt member 76, and rotates the belt member 76 by rotating the driving roll 72 to rotate the paper P Is transported to the position of the fixing unit 64 (see FIG. 1) on the downstream side in the transport direction.

  Note that the rotation speed of the suction fan 79 is variable, and the rotation speed is controlled by a control device 20 (see FIG. 3) described later. That is, the magnitude of the suction force can be controlled by the control of the control device 20.

  Next, the configuration of the main part of the control system of the image forming apparatus 10 according to the present embodiment will be described. FIG. 3 is a block diagram illustrating a main configuration of a control system of the image forming apparatus 10 according to the present embodiment. In the control system of FIG. 3, a configuration in which attention is paid to the portion related to the control of the suction conveyance devices 26, 28, and 30 is shown.

  As shown in FIG. 3, the image forming apparatus 10 according to the present embodiment includes a control device 20 as an example of a control unit, and the control device 20 causes the sheet P to be formed by a plurality of suction conveyance devices 26, 28, and 30. The suction state is controlled.

  Specifically, the control device 20 includes a central processing unit (CPU) 20A, a read only memory (ROM) 20B, a random access memory (RAM) 20C, and an input / output port 20D. They are connected to each other via a bus 20E such as a bus and a control bus.

  The ROM 20B stores various programs such as a program for controlling the suction conveyance devices 26, 28, and 30. Various controls are performed by the CPU 20A developing and executing the programs on the RAM 20C.

  Suction fan motors 26M, 28M, and 30M corresponding to the operation unit 22, the registration sensor 24, and the suction conveyance devices 26, 28, and 30 are connected to the input / output port 20D, respectively.

  The operation unit 22 includes settings relating to the paper P on which image formation is performed, buttons for performing various operations, and the like. Paper information (for example, paper size, paper type, thickness of the paper P, etc.) set by the operation unit 22 ) Is input to the control device 20.

  The registration sensor 24 is provided on the upstream side of the secondary transfer roll 60 in the transport direction of the paper P, detects the leading edge of the paper P, and outputs the detection result to the control device 20.

  Each of the suction fan motors 26M, 28M, and 30M rotates a suction fan 79 provided in each of the suction conveyance devices 26, 28, and 30, respectively.

  In the present embodiment, the control device 20 controls the suction fan motors 26M, 28M, and 30M of the suction conveyance devices 26, 28, and 30 to control the suction force by the suction fan 79, and the transfer speed and the fixing speed. Absorbs the speed difference.

  Specifically, the control device 20 acquires the paper information set by the operation unit 22, and the set paper P has a length equal to or longer than the distance between the secondary transfer roll 60 and the fixing unit 64. It is determined whether or not it is paper P. In addition, as the distance between the secondary transfer roll 60 and the fixing unit 64, which is a determination criterion, the distance of the conveyance path along the plurality of suction conveyance devices 26, 28, and 30 is applied, but the secondary transfer roll A linear distance connecting 60 and the fixing unit 64 may be applied.

  Here, when a sheet P longer than the distance between the secondary transfer roll 60 and the fixing unit 64 is set, the leading end of the sheet P is detected by the registration sensor 24 and then the leading end of the sheet P is detected by the fixing unit 64. Is measured by a counter or the like. Then, at the timing when the leading edge of the paper P reaches the fixing unit 64, the control device 20 reduces the suction force of at least one suction conveyance device other than the suction conveyance device 26 on the transfer side or stops the suction. Take control. Thus, even if a speed difference between the transfer speed and the fixing speed occurs, the speed difference is absorbed by at least one portion of the suction conveyance device other than the suction conveyance device 26 on the transfer side. Further, since the suction force is maintained in the transfer-side suction / conveyance device 26, the posture of the paper P at the time of transfer does not change, and even if a difference occurs between the transfer speed and the fixing speed, the influence on the image is suppressed. Is done.

  In the present embodiment, the control device 20 has two suction conveyance devices 28 other than the transfer-side suction conveyance device 26 as shown in FIG. 4A at the timing when the leading edge of the paper P reaches the fixing unit 64. The drive of each suction fan motor 26M, 28M, 30M of each suction conveyance device 26, 28, 30 is controlled so as to reduce the suction force of 30 or stop the suction. Thereby, for example, when the transfer speed is faster than the fixing speed, the sheet P is loosened in the portions of the suction conveyance devices 28 and 30 where the suction force is reduced or the suction is stopped, and the speed difference is absorbed. On the other hand, when the transfer speed is slower than the fixing speed, the sheet P is linearly conveyed from the suction conveyance device 26 to the fixing unit 64 in the portions of the suction conveyance devices 28 and 30 where the suction force is reduced or the suction is stopped. The speed difference is absorbed.

  Alternatively, as illustrated in FIG. 4B, the control device 20 is configured so that the suction force of the suction conveyance device 28 in the center other than the suction conveyance device 26 on the transfer side is the timing at which the leading edge of the paper P reaches the fixing unit 64. The suction fan motors 26M, 28M, and 30M of the suction conveyance devices 26, 28, and 30 are controlled so that the suction force of the suction conveyance device 30 on the fixing unit 64 side is maintained. Also good. Accordingly, the posture of the paper P at the time of transfer is maintained, and the posture of the paper P incident on the fixing unit 64 is also maintained. Further, the contact of the paper P with the housing of the fixing unit 64 when the paper P is loosened is suppressed. For example, when the transfer speed is faster than the fixing speed, the sheet P is slackened in the portion of the suction conveyance device 28 where the suction force is reduced or suction is stopped, and the speed difference is absorbed. On the other hand, when the transfer speed is slower than the fixing speed, the sheet P is lifted from the suction conveyance device 28 at the portion of the suction conveyance device 28 where the suction force is reduced or the suction is stopped, and the paper P is conveyed and the speed difference is increased. Absorbed.

  In the following description, as shown in FIG. 4A, two suction conveyance devices other than the transfer-side suction conveyance device 26 at the timing when the control device 20 reaches the fixing portion 64 at the leading end of the paper P. An example will be described in which the driving of the suction fan mora of each suction conveyance device 26, 28, 30 is controlled so that the suction force of 28, 30 is reduced.

  Next, specific processing performed by the control device 20 of the image forming apparatus 10 according to the present embodiment configured as described above will be described. FIG. 5 is a flowchart illustrating an example of the flow of processing performed by the control device 20 of the image forming apparatus 10 according to the present embodiment. Note that the processing in FIG. 5 is a flowchart that focuses on a characteristic part that controls the suction force of the plurality of suction conveyance devices 26, 28, and 30. The processing in FIG. 5 starts when the user operates the operation unit 22 to perform various settings such as the setting of the paper P and instruct the image formation.

  In step 100, the CPU 20 </ b> A acquires the paper information set by the operation unit 22 and proceeds to step 102.

  In step 102, the CPU 20A controls the driving of the suction fan motors 26M, 28M, 30M of the suction conveyance devices 26, 28, 30 to start the suction of the suction conveyance devices 26, 28, 30 and proceeds to step 104. . As a result, when the paper P passes through the secondary transfer roll 60, the paper P is transported while being sucked by the suction fans 79 of the suction transport devices 26, 28, and 30.

  In step 104, the CPU 20A determines whether or not the sheet P has a length equal to or longer than the distance between the transfer and the fixing based on the acquisition result of the sheet information. If the determination is negative, the processing is terminated as it is, and if the determination is affirmative, the routine proceeds to step 106.

  In step 106, the CPU 20 </ b> A determines whether it is time for the leading edge of the paper P to reach the fixing unit 64. In the present embodiment, in this embodiment, after the leading edge of the paper P is detected by the registration sensor 24, counting is started by a counter or the like, and it is determined whether or not a predetermined count reaching the fixing unit 64 has been reached. The process waits until the determination is affirmed and proceeds to step 108. The determination in step 106 may be performed by providing a sensor that detects the leading edge of the paper P in the fixing unit 64. Alternatively, determination may be made by providing a sensor in at least one of the plurality of suction conveyance devices 26, 28, 30.

  In step 108, the CPU 20A reduces the suction force of the suction conveyance devices 28, 30 other than the transfer-side suction conveyance device 26, and the suction fan motors 28M, 30M of the two suction conveyance devices 28, 30 other than the transfer side. To control. Thus, the paper P is transported while being sucked by the suction transport devices 26, 28, and 30 until the paper P is transported from the transfer position to the fixing position. When the leading edge of the paper P reaches the fixing position, the suction force of the two suction conveyance devices 28 and 30 other than the transfer side is reduced. The difference in fixing speed is absorbed. In addition, since the suction force of the transfer-side suction / conveyance device 26 is maintained, a change in the posture of the paper P at the time of transfer is suppressed, and a change in image quality is also suppressed. When reducing the suction force of the suction conveyance devices 28 and 30 other than the transfer-side suction conveyance device 26, the sheet P is sequentially conveyed upstream from the fixing-side suction conveyance device 30 on the downstream side in the conveyance direction. The suction force may be reduced toward the side. Accordingly, it is possible to smoothly absorb the speed difference when the fixing speed is slower than the transfer speed, compared to the case where the suction force is reduced or the suction is stopped sequentially from the upstream side in the conveyance direction of the paper P. Alternatively, when the suction force of the suction conveyance devices 28 and 30 other than the transfer-side suction conveyance device 26 is reduced, the sheet P is sequentially transported downstream from the fixing suction suction conveyance device 28 on the upstream side in the conveyance direction of the paper P. The suction force may be reduced toward As a result, even if the sheet P is loosened, it is likely to occur in the center portion, so that the contact of the sheet P with the casing of the fixing unit 64 is suppressed.

  Subsequently, a process of a modified example performed by the control device 20 of the image forming apparatus 10 according to the present embodiment will be described. FIG. 6 is a flowchart illustrating an example of a processing flow of a modification performed by the control device 20 of the image forming apparatus 10 according to the present embodiment. Note that the processing in FIG. 6 is also a flowchart focusing on the characteristic part that controls the suction force of the plurality of suction conveyance devices 26, 28, and 30. 6 is started when the operation unit 22 is operated by the user and various settings such as the setting of the paper P are performed and an image formation is instructed. Further, the same processing in FIG. 5 will be described with the same reference numerals.

  In step 100, the CPU 20 </ b> A acquires the paper information set by the operation unit 22 and proceeds to step 101.

  In step 101, the CPU 20 </ b> A sets a suction force corresponding to the thickness of the paper P based on the paper information acquisition result, and proceeds to step 102. For example, the suction force is set to be weaker as the paper P is thinner.

  In step 102, the CPU 20 </ b> A controls the driving of the suction fan motors 26 </ b> M, 28 </ b> M, 30 </ b> M of the suction conveyance devices 26, 28, 30, and the suction conveyance devices 26, 28, 30 with the suction force set in step 101. Is started and the routine proceeds to step 104. As a result, when the paper P passes through the secondary transfer roll 60, the paper P is transported while being sucked by the suction fans 79 of the suction transport devices 26, 28, and 30. Further, since the sheet P is conveyed while being sucked with a suction force set in accordance with the thickness of the sheet P, flapping of the sheet P and generation of wrinkles are suppressed.

  In step 104, the CPU 20A determines whether or not the sheet P has a length equal to or longer than the distance between the transfer and the fixing based on the acquisition result of the sheet information. If the determination is negative, the processing is terminated as it is, and if the determination is affirmative, the routine proceeds to step 106.

  In step 106, the CPU 20 </ b> A determines whether it is time for the leading edge of the paper P to reach the fixing unit 64. In the present embodiment, in this embodiment, after the leading edge of the paper P is detected by the registration sensor 24, counting is started by a counter or the like, and it is determined whether or not a predetermined count reaching the fixing unit 64 has been reached. The process waits until the determination is affirmed and proceeds to step 108. The determination in step 106 may be performed by providing a sensor that detects the leading edge of the paper P in the fixing unit 64. Alternatively, determination may be made by providing a sensor in at least one of the plurality of suction conveyance devices 26, 28, 30.

  In step 108, the CPU 20A reduces the suction force of the suction conveyance devices 28, 30 other than the transfer-side suction conveyance device 26, and the suction fan motors 28M, 30M of the two suction conveyance devices 28, 30 other than the transfer side. To control. Thus, the paper P is transported while being sucked by the suction transport devices 26, 28, and 30 until the paper P is transported from the transfer position to the fixing position. When the leading edge of the paper P reaches the fixing position, the suction force of the two suction conveyance devices 28 and 30 other than the transfer side is reduced. The difference in fixing speed is absorbed. In addition, since the suction force of the transfer-side suction / conveyance device 26 is maintained, a change in the posture of the paper P at the time of transfer is suppressed, and a change in image quality is also suppressed. When reducing the suction force of the suction conveyance devices 28 and 30 other than the transfer-side suction conveyance device 26, the sheet P is sequentially conveyed upstream from the fixing-side suction conveyance device 30 on the downstream side in the conveyance direction. The suction force may be reduced toward the side. Accordingly, it is possible to smoothly absorb the speed difference when the fixing speed is slower than the transfer speed, compared to the case where the suction force is reduced or the suction is stopped sequentially from the upstream side in the conveyance direction of the paper P. Alternatively, when the suction force of the suction conveyance devices 28 and 30 other than the transfer-side suction conveyance device 26 is reduced, the sheet P is sequentially transported downstream from the fixing suction suction conveyance device 28 on the upstream side in the conveyance direction of the paper P. The suction force may be reduced toward As a result, even if the sheet P is loosened, it is likely to occur in the center portion, so that the contact of the sheet P with the casing of the fixing unit 64 is suppressed.

  In the above-described embodiment, an example in which three suction conveyance devices 26, 28, and 30 are provided has been described. However, the number of suction conveyance devices is not limited to three, and may be two or four or more. Good.

  Moreover, the process shown in FIG.5 and FIG.6 performed with the control apparatus 20 which concerns on said embodiment is good also as a process performed by software, and it is good also as a process performed by hardware, and combined both. It is good also as processing. The processing performed by the control device 20 may be stored in a storage medium as a program and distributed.

  Further, the present invention is not limited to the above, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 20 Control apparatus 22 Operation part 24 Registration sensor 26, 28, 30 Suction conveyance apparatus 26M, 28M, 30M Suction fan motor 60 Secondary transfer roll 64 Fixing part

Claims (7)

The recording medium is provided between a transfer unit that transfers an image to a recording medium and a fixing unit that fixes the image transferred by the transfer unit to the recording medium, along the conveyance direction of the recording medium. A plurality of suction conveyance units that convey while sucking,
When the recording medium having a length equal to or longer than the distance between the transfer unit and the fixing unit is conveyed and the leading end reaches the fixing unit, at least one suction conveyance provided outside the transfer unit side A control unit that performs suction control to reduce the suction force of the part or stop suction;
An image forming apparatus. Three or more suction conveyance units are provided,
2. The image formation according to claim 1, wherein the control unit performs, as the suction control, control to reduce suction force of a suction conveyance unit provided at a position other than both ends in the conveyance direction among the plurality of suction conveyance units or stop suction. 3. apparatus.   When the control unit lowers the suction force of the plurality of suction conveyance units or stops the suction, the control unit performs a control to reduce the suction force or stop the suction in order from the suction conveyance unit on the downstream side in the conveyance direction of the recording medium. The image forming apparatus according to claim 1, wherein the image forming apparatus is performed.   When the control unit lowers the suction force of the plurality of suction conveyance units or stops the suction, the control unit sequentially reduces the suction force or stops the suction from the suction conveyance unit on the upstream side in the conveyance direction of the recording medium. The image forming apparatus according to claim 1, wherein the image forming apparatus is performed.   The image forming apparatus according to claim 1, wherein the control unit further controls the suction force of the suction conveyance unit so that the suction force becomes weaker as the recording medium is thinner.   The plurality of suction conveyance units are disposed below the apparatus along a straight line connecting the transfer unit and the fixing unit, and a movement locus when the recording medium is conveyed along the plurality of suction conveyance units is convex downward. The image forming apparatus according to claim 1, wherein the image forming apparatus is arranged so as to draw a curved line.   An image forming program for causing a computer to function as a control unit of the image forming apparatus according to claim 1.