Image forming apparatus

Abstract

To provide an image forming apparatus capable of suppressing heating by a heat source before a sheet reaches the heat source.SOLUTION: An image forming apparatus 100 includes: an image forming section 12; a conveying section 15; a drying section 3 and a control section 8. The image forming section 12 forms an image on a sheet P. The conveying section 15 conveys the sheet P from an upstream side to a downstream side of the image forming section 12. A drying section 3 has a heater 32 and heats and dries the sheet P on which the image is formed. A first detection section 41 detects carrying-in of the sheet P from the conveying section 15 to the drying section 3. The control section 8 controls the drying section 3. The control section 8 suppresses heating by the drying section 3 when the first detection section 41 detects that the sheet P is carried in the drying section 3 earlier than a determination threshold K.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] The image forming system described in Patent Document 1 includes a printer and a drying device. The drying device has a transport unit including an endless belt that transports the transported sheet, and a first drying section equipped with a heat source that radiates infrared rays toward a portion of the transport section. In this image forming system, after the sheet is detected in an area facing the heat source, excessive heating is determined. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-121194 Summary of the Invention [Problem to be solved by the invention]

[0004] In the image forming system described in Patent Document 1, processing starts after the sheet reaches the heat source, so heating by the heat source cannot be suppressed until the sheet reaches the heat source.

[0005] SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an image forming apparatus that can suppress heating by a heat source before a sheet reaches the heat source. [Means for solving the problem]

[0006] The image forming apparatus according to the present invention includes an image forming unit, a conveying unit, a drying unit, and a control unit. The image forming unit forms an image on a recording medium. The conveying unit conveys the recording medium from the upstream side to the downstream side of the image forming unit. The drying unit has a heater and heats and dries the recording medium on which the image has been formed. The first detection unit detects the recording medium being transported from the transport unit to the drying unit. The control unit controls the drying unit. When the first detection unit detects that the recording medium is being transported into the drying unit earlier than a judgment threshold, the control unit suppresses heating by the drying unit. [Effects of the Invention]

[0007] According to the image forming apparatus of the present invention, heating of the sheet by the heat source can be suppressed before the sheet reaches the heat source. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view illustrating an appearance of an image forming apparatus according to an embodiment of the present disclosure. [Figure 2] FIG. 1 illustrates an example of a configuration of an image forming apparatus. [Figure 3] FIG. 2 is a block diagram showing an example of the configuration of a control unit. [Figure 4] 4 is a flowchart illustrating an example of heating suppression control. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present disclosure will be described with reference to the drawings. In the following description, the same or corresponding parts will be denoted by the same reference numerals and will be commonly referred to.

[0010] The configuration of an image forming apparatus 100 will be described with reference to Figures 1 and 2. Figure 1 is a perspective view showing the appearance of an image forming apparatus 100 according to an embodiment of the present disclosure. Figure 2 is a diagram showing an example of the configuration of the image forming apparatus 100.

[0011] Image forming apparatus 100 is an inkjet recording device, such as a monochrome printer or color printer capable of double-sided printing, that uses aqueous ink to form an image on printing paper (hereinafter sometimes referred to as paper) P. Furthermore, paper P may be any type of paper, such as plain paper, copy paper, recycled paper, thin paper, cardboard, or glossy paper.

[0012] As shown in FIGS. 1 and 2, image forming apparatus 100 includes a main body 1, a drying section 3, a post-processing section 5, an operation section 7, a control section 8, and a first detection section 41. The main body 1 forms an image on a sheet P. The drying section 3 dries the sheet P in the process of relaying the sheet P on which the image has been formed from the main body 1 to the post-processing section 5. The post-processing section 5 performs post-processing on the sheet P on which the image has been formed, and discharges the sheet P. The sheet P corresponds to, for example, a "recording medium."

[0013] In this embodiment, in the image forming apparatus 100, the conveying direction from the main body 1 toward the post-processing section 5 is defined as the forward direction X1, and the opposite direction is defined as the backward direction X2. The left side when the image forming apparatus 100 is viewed from the backward direction X2 is defined as the left side Y1, and the opposite direction is defined as the right side Y2. Furthermore, in the up-down direction Z, which is perpendicular to the front-to-back direction X and the left-to-right direction Y of the image forming apparatus 100, the side on which the operation unit 7 is located with respect to the main body 1 is defined as the upward direction Z1, and the opposite direction is defined as the downward direction Z2. Note that these directions do not limit the orientation of the image forming apparatus 100 of the present invention when in use.

[0014] First, we will explain the configuration of the main body 1. As shown in Figure 2, the main body 1 has a housing 11, an image forming unit 12, a paper feed unit 13, a conveying unit 15, a conveying path 17, and a sending unit 19.

[0015] The housing 11 houses the image forming unit 12, the paper feeding unit 13, etc. An outlet 16 is formed in the housing 11. The outlet 16 is located at the top of the side surface of the front X1 of the housing 11. The outlet 16 conveys the paper P toward the drying unit 3.

[0016] The paper feed unit 13 supplies paper P to the transport path 17. For example, a plurality of paper feed units 13 may be provided. The plurality of paper feed units 13 are arranged side by side in the vertical direction Z at the bottom of the housing 11. Each of the plurality of paper feed units 13 has a paper cassette 14 and a feeding device 21.

[0017] The paper cassette 14 stores paper sheets P. The feeding device 21 feeds paper sheets P from the paper cassette 14 to the conveying path 17.

[0018] The conveying path 17 is a conveying passage for conveying the paper P. The conveying path 17 runs from the feeding device 21 of the paper feeding unit 13 through the image forming unit 12 toward the discharge port 16. The conveying path 17 is provided with a reversing path 18, a sending unit 19, and a pair of registration rollers 20.

[0019] The reversing path 18 reverses the front and back of the paper P. The reversing path 18 branches off from the conveying path 17 downstream of the image forming unit 12 in the conveying direction of the paper P. The reversing path 18 merges with the conveying path 17 upstream of the image forming unit 12. The sending unit 19 is disposed in the vicinity of the discharge port 16.

[0020] The pair of registration rollers 20 is disposed in the transport path 17 on the upstream side of the image forming unit 12 in the transport direction. The pair of registration rollers 20 corrects the inclination of the sheet P that has come into contact with the pair of registration rollers 20 and stopped relative to the image forming unit 12. Then, in order to synchronize the image formation timing with the transport timing of the sheet P, the pair of registration rollers 20 makes the sheet P wait temporarily, and then sends the sheet P to the image forming unit 12 in accordance with the image formation timing.

[0021] The image forming unit 12 forms an image on the paper P. Specifically, the image forming unit 12 forms an image by ejecting ink onto the paper P. The image forming unit 12 is disposed above the paper feed unit 13. The image forming unit 12 has four recording heads 22.

[0022] The four recording heads 22 form an image on the paper P using toner of multiple colors. Specifically, the four recording heads 22 eject ink of yellow, cyan, magenta, and black, respectively. Each recording head 22 is connected to an ink tank (not shown) of the corresponding color via an individual supply pump (not shown).

[0023] The transport unit 15 transports the paper P from the upstream side to the downstream side of the image forming unit 12. The transport unit 15 transports the paper P in the direction in which the four recording heads 22 are arranged. The transport unit 15 has, for example, a drive roller 151, a motor (not shown) that drives the drive roller 151, a driven roller 152, and an endless belt 153 that is stretched between the drive roller 151 and the driven roller 152. In this embodiment, the transport unit 15 is provided with a suction mechanism that sucks the paper P.

[0024] Next, we will explain the operation of the main body 1. First, in the paper feed unit 13, the feed device 21 feeds paper P from the paper cassette 14 to the conveyance path 17. The fed paper P is transported along the conveyance path 17 and is adsorbed to the upper surface of the endless belt 153 in the image forming unit 12. Then, while the paper P is being transported in accordance with the rotation of the conveyance unit 15, an image is formed on the paper P by ink ejected from each recording head 22.

[0025] The paper P on which the image has been formed is transported forward X1 by the transport unit 15 and then sandwiched in the output unit 19. The output unit 19 has a pair of rollers arranged in the vertical direction Z. The timing of the rotation drive of the output unit 19 is adjusted. The output unit 19 discharges the paper P from the discharge opening 16 at a predetermined timing. The paper P is discharged from the discharge opening 16 with the side on which the image has been formed facing upward.

[0026] When double-sided printing is performed, the paper P with an image formed on one side is transported to the reversal path 18 and turned over. The paper P, which has been turned over, is transported to the transport path 17 and adsorbed to the upper surface of the endless belt 153. Then, an image is formed on the other side while the paper P is transported in accordance with the rotation of the endless belt 153. The paper P is discharged from the discharge port 16 with the last printed side facing upward.

[0027] Next, we will explain the configuration of the drying unit 3. The drying unit 3 is provided separately from the main body unit 1 and the post-processing unit 5, and is connected to both the main body unit 1 and the post-processing unit 5. The drying unit 3 dries the paper P while relaying the paper P from the main body unit 1 to the post-processing unit 5.

[0028] The drying unit 3 heats and dries the paper P on which an image has been formed. As shown in Fig. 2, the drying unit 3 has a housing 31, a heater 32, a drying conveying unit 33, a fan 34, a conveying roller pair 35, a receiving port 36, a delivery port 37, and a first detection unit 41.

[0029] The housing 31 of the drying unit 3 is, for example, covered on its outer periphery with a cover that prevents heat from escaping. Of the sides of the housing 31, a receiving opening 36 for the paper P sent out from the main body unit 1 is formed on the side facing the rear X2. The receiving opening 36 is formed at the same height as the delivery opening 16 of the main body unit 1. Of the sides of the housing 31, a delivery opening 37 for the paper P is formed on the side facing the front X1. The delivery opening 37 is formed at the same height as the delivery entrance 55 of the post-processing unit 5.

[0030] The dry conveying section 33 conveys the paper P from the upstream side to the downstream side of the drying section 3. The dry conveying section 33 is below the heater 32 and conveys the paper P along a forward direction X1 from the receiving port 36 toward the delivery port 37. The dry conveying section 33 has, for example, a drive roller 331, a motor (not shown) that drives the drive roller 331, a driven roller 332, and an endless belt 333 that is stretched between the drive roller 331 and the driven roller 332.

[0031] The heater 32 heats the paper P on which an image has been formed. The heater 32 is arranged above Z1 the drying conveying section 33. The heater 32 dries the paper P placed on the endless belt 333. The heater 32 has, for example, a ceramic heater (not shown), fins (not shown), and a fan (not shown). The fins are provided around the ceramic heater. The fan is arranged upstream of the ceramic heater. The air heated by the heater 32 is accumulated inside the housing 31.

[0032] The fan 34 exhausts the air stagnating inside the housing 31 to the outside.

[0033] The transport roller pair 35 transports the paper sheet P dried by the heater 32 along the forward direction X1 from the dry transport section 33 toward the delivery port 37. The transport roller pair 35 is disposed on the transport path of the paper sheet P.

[0034] The first detection unit 41 detects the paper sheet P. The first detection unit 41 detects the paper sheet P being carried into the drying unit 3 from the transport unit 15. The first detection unit 41 is disposed, for example, at a position upstream of the heater 32 in the transport direction. Specifically, the first detection unit 41 is disposed at a position near the receiving port 36. The first detection unit 41 is, for example, a photoelectric sensor that detects the presence of the paper sheet P. Note that the first detection unit 41 is not limited to a photoelectric sensor. The first detection unit 41 may be a proximity sensor or a contact sensor.

[0035] Next, we will explain the configuration of the post-processing unit 5. The post-processing unit 5 performs post-processing on the paper P and then discharges the paper P to the outside of the image forming apparatus 100. The post-processing unit 5 has a housing 51, a punching device 52, a stapling device 53, and a center-folding device 54.

[0036] The housing 51 has an entrance 55, a first tray 56, a second tray 57, and a third tray 58.

[0037] The inlet 55 receives the paper P from the drying unit 3. The inlet 55 is formed on the side surface of the housing 51 on the rear X2 side.

[0038] The first tray 56, the second tray 57, and the third tray 58 are arranged on the side surface of the housing 51 on the front X1 side. A first discharge opening 56a, a second discharge opening 57a, and a third discharge opening 58a are formed on the side surface of the housing 51 on the front X1 side. The first tray 56 is arranged below the first discharge opening 56a. The second tray 57 is arranged below the second discharge opening 57a. The third tray 58 is arranged below the third discharge opening 58a.

[0039] The punching device 52 is disposed in the upper part of the housing 51, the stapling device 53 is disposed below the punching device 52, and the center-folding device 54 is disposed in the lower part of the housing 51. A first discharge outlet 56a is disposed on the front X1 side of the punching device 52. A second discharge outlet 57a is disposed on the front X1 side of the stapling device 53. A third discharge outlet 58a is disposed on the front X1 side of the center-folding device 54.

[0040] A first conveying path 59, a second conveying path 60, and a third conveying path 61 are formed in the housing 51. The first conveying path 59 runs from the entrance 55 through the punching device 52 toward the first discharge outlet 56a. The second conveying path 60 branches off from the first conveying path 59 downstream of the punching device 52 and runs through the stapling device 53 toward the second discharge outlet 57a. The third conveying path 61 branches off from the second conveying path 60 and runs through the folding device 54 toward the third discharge outlet 58a.

[0041] Next, the control unit 8 will be described with reference to Figures 2 and 3. Figure 3 is a block diagram showing an example of the configuration of the control unit 8.

[0042] The control unit 8 is configured with a processor such as a CPU (Central Processing Unit), a non-volatile memory (ROM: Read Only Memory), and a volatile memory (RAM: Random Access Memory). The control unit 8 also has an integrated circuit for image formation processing. The integrated circuit for image formation processing is configured, for example, with an ASIC (Application Specific Integrated Circuit). The ROM stores a control program in advance for causing the CPU to execute various arithmetic processing. The control program may be stored in the ROM instead of the memory unit 81. The RAM temporarily stores various arithmetic processing executed by the CPU. The control unit 8 controls the operation of the image forming apparatus 100 by executing the control program (a control program stored in advance in the memory unit 81 or the ROM).

[0043] The control unit 8 controls the image formation on the paper P. Specifically, the control unit 8 controls at least the drying unit 3 and the image forming unit 12. Furthermore, when a request for image formation on the paper P is made, the control unit 8 preferably initializes various parameters used to control the image formation on the paper P. The user may request the image formation on the paper P by operating the operation unit 7. The user may request the image formation on the paper P by operating an external device (for example, a personal computer).

[0044] As shown in FIG. 3, the control unit 8 is communicatively connected to the operation unit 7, the image forming unit 12, the conveying unit 15, the sending unit 19, the pair of resist rollers 20, the feeding device 21, the heater 32, the dry conveying unit 33, the fan 34, the first detection unit 41, the second detection unit 42, and the memory unit 81 via an interface (not shown).

[0045] The storage unit 81 is configured with a non-volatile memory. For example, the storage unit 81 is preferably a hard disk. The storage unit 81 preferably stores, for example, image data for printing, control programs related to various controls, and data used by the control programs. Examples of the control programs include a program that controls image formation on the paper P (hereinafter, sometimes referred to as the "first control program") and a program that prevents the heater 32 from overheating the paper P (hereinafter, sometimes referred to as the "second control program").

[0046] The first control program refers to a program for executing image formation on paper P. Examples of data used by the processor when executing the first control program include the amount of water-based ink ejected onto the printing area.

[0047] The second control program refers to a program for controlling the heater 32 and the fan 34. Examples of data used in the second control program include the timing of detection of the paper P by the first detection unit 41, the timing at which the first image is formed on the paper P at the start of image formation, and a determination threshold K.

[0048] The control unit 8 suppresses heating by the dryer 3. Specifically, when the first detection unit 41 detects that the sheet P is being conveyed into the dryer 3 earlier than the determination threshold K, the control unit 8 suppresses heating by the dryer 3. This allows heating by the heater 32 to be suppressed before the sheet P reaches the heater 32. Specifically, if the sensor does not detect any remaining sheet P immediately after the image forming apparatus 100 starts operating, the dry conveying unit 33 is not operated. Therefore, the sheet P sent from the main body 1 may interfere with the dry conveying unit 33. If the sheet P interferes with the dry conveying unit 33, wrinkles may occur in the sheet P. Wrinkled sheet P may cause a jam near the heater 32. Therefore, the occurrence of wrinkles is predicted when the sheet P is conveyed into the dryer 3, and heating by the heater 32 is suppressed in advance if wrinkles are predicted.

[0049] 2 and 3, the image forming apparatus 100 will be further described. The image forming apparatus 100 further includes a second detection unit .

[0050] As shown in FIGS. 2 and 3 , the second detection unit 42 detects the paper P. The second detection unit 42 is disposed in a position between the image forming unit 12 and the drying unit 3 in the conveying unit 15. Specifically, the second detection unit 42 is disposed at the most downstream position in the conveying unit 15. In other words, the second detection unit 42 is disposed between the downstream side of the image forming unit 12 and the sending unit 19. The second detection unit 42 detects the paper P on which an image has been formed. The second detection unit 42 is, for example, a photoelectric sensor that detects the presence of the paper P. In this embodiment, one or more sheets of paper P can remain on the conveying path 17 between the second detection unit 42 and the sending unit 19. Furthermore, no sensor that detects the paper P is disposed on the conveying path 17 between the second detection unit 42 and the sending unit 19. Therefore, a section in which the paper P remains is formed on the conveying path 17 between the second detection unit 42 and the sending unit 19.

[0051] The upstream end of the dry conveying section 33 is close to the receiving port 36. In other words, the first detection section 41 is disposed in a position near the entrance of the dry conveying section 33. This allows the first detection section 41 to detect the paper P before it is transported into the dry conveying section 33. The control section 8 can suppress heating by the drying section 3 before the paper P is transported into the dry conveying section 33.

[0052] When the second detection unit 42 detects the sheet P after the start of image formation, the control unit 8 starts conveyance by the dry conveyance unit 33. Specifically, when the second detection unit 42 detects the sheet P, the control unit 8 starts driving the drive roller 331. This allows the dry conveyance unit 33 to convey the sheet P on which the image has been formed to an area facing the heater 32 while suppressing the conveyance operation. When a start button (not shown) that starts the image forming apparatus 100 is operated, the control unit 8 starts operation of the image forming unit 12, conveyance unit 15, delivery unit 19, pair of registration rollers 20, feeder device 21, and heater 32. When the second detection unit 42 or one of the multiple sheet sensors (not shown) arranged in the main body unit 1 detects the sheet P after the start of image formation, the dry conveyance unit 33 starts its conveyance operation.

[0053] The control unit 8 sets a determination threshold K. The determination threshold K is set based on the time it takes for the first sheet P on which an image is formed to reach the first detection unit 41 after the start of image formation. This makes it possible to determine whether the sheet P detected by the first detection unit 41 is a sheet P that remained on the conveyance path 17 of the main body unit 1. Specifically, the time when an image is first formed is the time when the pair of registration rollers 20 conveys the sheet P to the image forming unit 12. The sheet P requires a travel time equivalent to the determination threshold K from the time when the image is first formed to the time when it reaches the first detection unit 41. In other words, if the first detection unit 41 detects the sheet P before the time equivalent to the determination threshold K has elapsed after the start of image formation, the detected sheet P is predicted to be a sheet P that remained on the conveyance path 17 in the main body unit 1 (for example, in the section between the second detection unit 42 and the sending unit 19). In this embodiment, the determination threshold K is set to the time it takes for the sheet P on which an image is formed to reach the first detection unit 41.

[0054] The control unit 8 has a counter (not shown). After the start of image formation, the control unit 8 measures the time it takes for the first sheet P on which an image is formed to reach the first detection unit 41 multiple times. The control unit 8 measures this time each time the image forming apparatus 100 starts operating. The control unit 8 sets the determination threshold K based on the multiple measured times. This makes it possible to set a highly accurate determination threshold K. The control unit 8 accumulates the measurement time for each type of sheet P (basis weight, etc.) and updates the determination threshold K based on the measured time. By periodically updating the determination threshold K, the control unit 8 obtains a determination threshold K that corresponds to the type of sheet P as well as the working environment (temperature, humidity, etc.).

[0055] Next, the processing executed by the control unit 8 will be described with reference to the flowchart of Fig. 4. Fig. 4 is a flowchart showing an example of heating suppression control. As shown in Fig. 4, a program stored in the storage device of the storage unit 81 (see Fig. 3) causes the processor of the control unit 8 to execute the processing from step S1 to step S9.

[0056] 4, in step S1, the control unit 8 reads various pieces of information such as each detection signal and a determination threshold K corresponding to the type of paper P. The process proceeds to step S2.

[0057] In step S2, the start button for starting the image forming apparatus 100 is operated, and the control unit 8 determines whether image formation by the image forming apparatus 100 has started. If the control unit 8 determines that image formation has not started (No in step S2), the process ends. If the control unit 8 determines that image formation has started (Yes in step S2), the process proceeds to step S3.

[0058] In step S3, the control unit 8 starts counting with a counter and measures the elapsed time T that has passed since the image was formed on the first sheet P. The process proceeds to step S4.

[0059] In step S4, the control unit 8 determines whether the first detection unit 41 has detected the paper sheet P. If the control unit 8 determines that the first detection unit 41 has not detected the paper sheet P (No in step S4), the process proceeds to step S8. If the control unit 8 determines that the first detection unit 41 has detected the paper sheet P (Yes in step S4), the process proceeds to step S5.

[0060] In step S5, the control unit 8 determines whether the elapsed time T is less than the determination threshold K. If the control unit 8 determines that the elapsed time T is equal to or greater than the determination threshold K (No in step S5), the process ends. If the elapsed time T is equal to or greater than the determination threshold K, it is determined that the first sheet P on which an image has been formed since the start-up of the image forming apparatus 100 has been detected. If the control unit 8 determines that the elapsed time T is less than the determination threshold K (Yes in step S5), the process proceeds to step S6. It is determined that the sheet P remaining between the second detection unit 42 and the delivery unit 19 has been detected. In other words, the dry conveying unit 33 is not being driven, and the delivered sheet P may interfere with the dry conveying unit 33, causing wrinkles in the sheet P.

[0061] In step S6, the control unit 8 stops heating by the heater 32. The process proceeds to step S7. As a result, the temperature inside the drying unit 3 stops increasing.

[0062] In step S7, the control unit 8 starts operating the fan 34. The operation of the fan 34 causes the heated air inside the housing 31 to be discharged to the outside, and the process then ends.

[0063] If the answer is No in step S4, then in step S8, the control unit 8 determines whether the second detection unit 42 has detected the paper P. If the control unit 8 determines that the second detection unit 42 has not detected the paper P (No in step S8), the process ends. If the control unit 8 determines that the second detection unit 42 has detected the paper P (Yes in step S8), the process proceeds to step S9.

[0064] In step S9, the control unit 8 starts the operation of the drying and conveying unit 33. The process then ends.

[0065] The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above embodiments and can be embodied in various forms without departing from the spirit and scope of the present invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in the above embodiments. For example, some components may be omitted from all components shown in the embodiments. The drawings mainly show each component in a schematic manner for ease of understanding, and the number of each component shown may differ from the actual number due to the convenience of drawing. Furthermore, the components shown in the above embodiments are merely examples and are not particularly limited, and various modifications are possible without substantially departing from the effects of the present invention.

[0066] (1) As described with reference to FIGS. 1 to 4, in the above embodiment, heating by the heater 32 is stopped when the paper P is conveyed into the drying unit 3 earlier than the determination threshold K. However, this is not limited to this. The heating level (temperature) by the heater 32 may be reduced. In this case, it is preferable to reduce the heating level as the paper P is more likely to become jammed. For example, the heating level of the heater 32 may be reduced as the conveying speed of the conveying unit 15 is slower.

[0067] (2) As described with reference to FIGS. 1 to 4, in the above embodiment, the time it takes for the paper P on which an image has been formed to reach the first detection unit 41 is set as the determination threshold K, but this is not limited to this. The time it takes for the paper P on which an image has been formed to reach the first detection unit 41 may be corrected, and this corrected value may be set as the determination threshold K. In this case, the more likely it is that the paper P will jam, the smaller the determination threshold K is corrected, and the more unlikely it is that the paper P will jam, the larger the determination threshold K is corrected. [Industrial Applicability]

[0068] The present invention can be used in the field of image forming devices. [Explanation of symbols]

[0069] 3:Drying section 8: Control section 12: Image forming unit 15: Transport section 32: Heater 33: Drying conveying section 41: First detection unit 42: Second detection unit 100: Image forming device K: Decision threshold

Claims

1. an image forming unit that forms an image on a recording medium; a conveying unit that conveys the recording medium from the upstream side to the downstream side of the image forming unit; a drying section having a heater for heating and drying the recording medium on which the image is formed; a first detection unit that detects the recording medium being carried from the conveyance unit to the drying unit; a control unit that controls the drying unit; Equipped with The control unit suppresses heating by the drying unit when the first detection unit detects that the recording medium is transported into the drying unit earlier than a determination threshold.

2. The image forming apparatus according to claim 1 , wherein the first detection unit is disposed in the vicinity of an entrance of the drying unit.

3. 3. The image forming apparatus according to claim 1, wherein the determination threshold is set based on a time taken for the recording medium on which the image is first formed to reach the first detection unit after the start of image formation.

4. The control unit measuring a time period from when the image formation starts until the recording medium on which the image is first formed reaches the first detection unit a plurality of times; The image forming apparatus according to claim 3 , wherein the determination threshold is set based on the time measured multiple times.

5. a second detection unit for detecting the recording medium at a position between the image forming unit and the drying unit in the conveying unit; the drying section has a drying conveying section, The control unit 3. The image forming apparatus according to claim 1, wherein, when the second detection unit detects the recording medium after the start of the image formation, the dry conveyance unit starts conveying the recording medium.

6. 3. The image forming apparatus according to claim 1, wherein the image forming unit forms the image by ejecting ink onto the recording medium.

Images