Image forming apparatus

Abstract

To provide a technology that can prevent the recording medium from becoming contaminated. [Solution] The image forming apparatus according to this technology comprises a drying unit, a transport path, a branching mechanism, and a control unit. The drying unit applies heat to a recording medium that has undergone image forming processing to dry the image and fix the image to the recording medium. The transport path includes a first transport path through which the dried recording medium is transported, and a second transport path and a third transport path that branch off from the first transport path downstream in the transport direction of the recording medium in the first transport path. The branching mechanism is switchable between a first connection state connecting the first transport path and the second transport path, and a second connection state connecting the first transport path and the third transport path. The control unit switches between the first connection state and the second connection state in accordance with switching between a normal mode and a test mode for checking the degree of drying of the image.

Description

Technical Field

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[0001] This technology relates to an image forming apparatus such as an inkjet printing apparatus, for example.

Background Art

[0002] Conventionally, image forming apparatuses such as inkjet printing apparatuses have been widely known. In an inkjet printing apparatus, printing on paper is performed by causing ink ejected from a head to adhere to the paper.

[0003] If the ink remains undried and the printed paper is conveyed through the conveyance path, there is a problem that the ink adheres to the rollers provided in the conveyance path as dirt. In this case, there is a problem that the ink adhering to the rollers adheres to subsequent paper, soiling the recording surface of the paper.

[0004] On the other hand, in the inkjet printing apparatus described in Patent Document 1 below, a drying unit for drying ink is arranged at a position downstream of the recording head. In the technology described in Patent Document 1, the ink printed on the paper is dried by this drying unit and fixed to the paper, so the problems of roller and paper contamination are alleviated to some extent.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Merely arranging a drying unit is insufficient as a technique for preventing soiling of the recording medium.

[0007] In light of the above circumstances, the objective is to provide a technology that can prevent the recording medium from becoming contaminated. [Means for solving the problem]

[0008] The image forming apparatus according to this technology comprises a drying section, a transport path, a branching mechanism, and a control unit. The drying unit applies heat to the recording medium that has undergone image formation processing, thereby drying the image and fixing it to the recording medium. The transport path includes a first transport path through which the dried recording medium is transported, and a second transport path and a third transport path that branch off from the first transport path downstream in the transport direction of the recording medium in the first transport path. The branching mechanism is capable of switching between a first connection state, which connects the first transport path and the second transport path, and a second connection state, which connects the first transport path and the third transport path. The control unit switches between the first connection state and the second connection state in accordance with the switching between the normal mode and the test mode for checking the dryness of the image.

[0009] In this image forming apparatus, the transport paths for the dried recording medium are separate for the normal mode and the test mode, as the downstream side of the first transport path is branched into a second transport path and a third transport path.

[0010] The test mode is used to check the dryness of an image, so components of the image (e.g., ink) may not be completely dry. However, in test mode, recording media containing undried images are transported along the transport path used in test mode (e.g., the third transport path). In other words, recording media containing undried images in test mode do not pass through the transport path used in normal mode (e.g., the second transport path).

[0011] This prevents the transport path used in normal mode (e.g., the second transport path) from becoming contaminated by components that make up the image (e.g., ink). Therefore, in normal mode, it is possible to prevent the recording medium from becoming contaminated by a contaminated transport path. [Effects of the Invention]

[0012] As described above, this technology provides a method that can prevent the recording medium from becoming contaminated. [Brief explanation of the drawing]

[0013] [Figure 1] A block diagram of an inkjet printing apparatus according to this embodiment. [Figure 2] This diagram shows the drying section and the discharge section. [Figure 3] This is a magnified view showing a part of the discharge section, illustrating its operation in normal mode. [Figure 4] This is a magnified view showing a part of the discharge section, illustrating the situation in test mode. [Figure 5] This is a flowchart showing the processing in the control unit of an inkjet printing device. [Figure 6] This is a flowchart showing the processing in the control unit of an inkjet printing device. [Figure 7] This figure shows an example of an image displayed on the screen of the display unit to recommend that the user switch to test mode. [Figure 8] This figure shows other examples of the first and second conveyor rollers, illustrating the situation in normal mode. [Figure 9] This figure shows other examples of the first and second conveyor rollers, and illustrates the situation in test mode. [Modes for carrying out the invention]

[0014] Hereinafter, embodiments of the present technology will be described while referring to the drawings.

[0015] <Overall Configuration and Configuration of Each Part>

[0016] FIG. 1 is a block diagram showing an inkjet printing apparatus 100 according to the present embodiment. The inkjet printing apparatus 100 (image forming apparatus) according to the present embodiment includes a control unit 10 that comprehensively controls each part of the apparatus, an input unit 60 to which user operations are input, and a display unit 70 (notification unit) capable of displaying video.

[0017] Further, the inkjet printing apparatus 100 includes, in order from the upstream side in the conveyance direction of the paper 2 (recording medium) (see FIG. 2), a supply unit 20 that supplies the paper 2, a printing unit 30 (image forming processing unit) that performs printing processing (image forming processing) on the paper 2 supplied from the supply unit 20, a drying unit 40 that dries an image (characters, figures, symbols, predetermined patterns, pictures, photos, etc.) formed by the ink attached to the paper 2 by the printing processing and fixes it on the paper 2, and a discharging unit 50 that discharges and holds the paper 2 dried by the drying unit 40.

[0018] In the present embodiment, a conveyance path 1 for conveying the paper 2 is formed in the path from the supply unit 20 to the discharging unit 50 via the printing unit 30 and the drying unit 40. In the example shown in FIG. 1, the conveyance path 1 is illustrated linearly for convenience, but generally, this conveyance path 1 is configured to be curved from the perspective of space saving in the arrangement within the apparatus.

[0019] The inkjet printing apparatus 100 may be configured to be capable of performing printing processing (duplex printing) on both the front and back surfaces of the paper 2. In this case, the inkjet printing apparatus 100 is further provided with a reversing unit that reverses the front and back surfaces of the paper. This reversing unit is configured to be able to reverse the front and back surfaces of the paper after drying by the drying unit 40, and is able to return the paper to the upstream side of the printing unit 30 via the reversing path.

[0020] In this embodiment, the inkjet printer 100 has two operating modes: a normal mode and a test mode, and operates in either one of these modes. The normal mode is the mode in which the normal printing process (the process in which the image desired by the user is printed on the paper 2) is performed. On the other hand, the test mode is a mode in which the user (or the control unit 10) checks the degree of drying of the ink (and the paper 2) attached to the paper 2 during the printing process and adjusts the temperature in the drying unit 40.

[0021] The control unit 10 includes, for example, a CPU (Central Processing Unit) and a motor driver that drives various motors in response to control signals from the CPU. The control unit 10 also includes a non-volatile memory that stores various programs and data necessary for CPU processing, and a volatile memory used as the CPU's workspace. Furthermore, the control unit 10 includes a communication unit that communicates with other parts of the device and with external devices.

[0022] The input unit 60 includes a mechanical push-button type operation unit and a contact sensor provided on the screen of the display unit 70. The input unit 60 detects various user operations input by the user and outputs information of the detected user operations to the control unit 10.

[0023] The display unit 70 is composed of, for example, a liquid crystal display, and displays various images on the screen in accordance with the control of the control unit 10.

[0024] The supply unit 20 is capable of storing a certain number of sheets of paper 2, and is configured to supply multiple stored sheets of paper 2 to the print unit 30 one sheet at a time as needed. Furthermore, the supply unit 20 is capable of correcting (resist correction) for lateral displacement and tilt angle displacement (skew) of the paper 2, and supplying the paper 2 to the print unit 30 while accurately transporting the paper 2 along the transport path 1.

[0025] This supply unit 20 includes a supply tray capable of storing a certain number of sheets of paper 2, a supply roller that guides the sheets of paper 2 one by one from the supply tray to the transport path 1, a registration roller that performs registration correction, and motors for driving each roller.

[0026] The printing unit 30 transports the paper 2 in the transport direction and performs the printing process by ejecting ink onto one side of the transported paper 2.

[0027] The printing unit 30 includes a transport belt for transporting the paper 2, a belt roller for rotating the transport belt, a motor for driving the belt roller, and the like. The printing unit 30 also includes multiple ink heads corresponding to different colors of ink (yellow, magenta, cyan, and black, etc.), an ink supply unit that stores different colored inks and supplies them to the corresponding ink heads, and the like.

[0028] Each of the multiple ink heads is equipped with multiple ejection nozzles that eject ink of the corresponding color. By adjusting the amount of ink ejected from the ejection nozzles of each ink head, color and black-and-white images are recorded on the paper 2.

[0029] Figure 2 shows the drying section 40 and the discharge section 50. Figure 3 is an enlarged view of a part of the discharge section 50, showing its operation in normal mode. Figure 4 is an enlarged view of a part of the discharge section 50, showing its operation in test mode.

[0030] The drying unit 40 transports the printed paper 2 downstream in the transport direction while drying the ink (image) attached to the paper 2 and fixing it to the paper 2. As shown in Figure 2, the drying unit 40 has a transport belt 42 that transports the paper 2 downstream in the transport direction (Y-axis direction), two belt rollers 43 that rotate the transport belt 42, and a heater 41 located on the opposite side of the transport path 1 from the transport belt 42.

[0031] The conveyor belt 42 rotates to transport the paper 2 placed on the belt downstream in the transport direction (Y-axis direction). The two belt rollers 43 are configured to rotate with the axis in the width direction (X-axis direction) of the transport path 1 as the central axis of rotation, and rotate the conveyor belt while contacting the inner circumference of the conveyor belt 42.

[0032] Of the two belt rollers 43, one is a drive roller driven by a power source such as a motor, and the other is a driven roller that rotates in accordance with the rotation of the drive roller. It is also possible for both belt rollers 43 to be drive rollers.

[0033] The heater 41 is positioned on the side of the paper 2 opposite the side that has been printed (in the case of double-sided printing, the side that has been most recently printed). The heater 41 applies heat to the ink that has adhered to the paper 2 during the printing process, drying the ink and thereby fixing it to the paper 2.

[0034] The heater 41 is capable of changing the temperature of the heat applied to the paper 2 after printing, according to the control unit 10. In this embodiment, however, the temperature of the heater 41 can only be changed in test mode, out of the normal mode and test mode.

[0035] In this example, a method was described in which the printed paper 2 is dried by the heat of the heater 41 in the drying unit 40, but a method of drying the printed paper 2 by blowing hot air onto the paper 2 is also possible. Any method can be adopted for the drying unit 40 as long as it is capable of drying the printed paper 2.

[0036] The discharge unit 50 is configured to discharge the paper 2 after drying by the drying unit 40 by transporting it in the transport direction (Y-axis direction), and to store the discharged paper 2.

[0037] In the discharge section 50, the transport path 1 (discharge path) branches into two transport paths 1 at a branching point on the downstream side in the transport direction (Y-axis direction). In this specification, the main transport path 1 before branching in the discharge section 50 is referred to as the first transport path 1a. Of the two transport paths 1 that branch off from the first transport path 1a, one transport path 1 is referred to as the second transport path 1b, and the other transport path 1 is referred to as the third transport path 1c.

[0038] A branching mechanism is provided at the branching point downstream of the first transport path 1a. The branching mechanism includes a thin plate-shaped rotating plate 54, a rotating mechanism (rotating shaft, gears, etc.) for rotating the rotating plate 54, and a motor as a drive source for the rotating mechanism.

[0039] The rotating plate 54 is rotatable around an axis in the X-axis direction (direction of the transport path width). The pivot axis of the rotating plate 54 is located at the upstream end in the transport direction (Y-axis direction) of both ends. The rotating plate 54 is switchable between a first connection state connecting the first transport path 1a and the second transport path 1b, and a second connection state connecting the first transport path 1a and the third transport path 1c.

[0040] As shown in Figure 3, when the operating mode is set to normal mode, the rotating plate 54 connects the first transport path 1a and the second transport path 1b, thereby setting the connection state of the transport path 1 to the first connection state. In normal mode, the paper 2 after drying by the drying unit 40 passes through the first transport path 1a and the second transport path 1b and is guided to the discharge tray.

[0041] On the other hand, as shown in Figure 4, when the operating mode is set to test mode, the rotating plate 54 connects the first transport path 1a and the third transport path 1c, thereby changing the connection state of the transport path 1 to the second connection state. In test mode, the paper 2 after drying by the drying unit 40 passes through the first transport path 1a and the third transport path 1c and is guided to the discharge tray.

[0042] In other words, the second transport path 1b is the transport path 1 used in normal mode, and the third transport path 1c is the transport path 1 used in test mode. Furthermore, the first transport path 1a is the transport path 1 used in both normal mode and test mode.

[0043] The output tray is capable of storing a certain number of sheets of paper 2. The output tray downstream of the second transport path 1b and the output tray downstream of the third transport path 1c may be separate and different output trays, or they may be the same output tray.

[0044] The first transport path 1a is equipped with a first transport roller 51 (discharge roller) and a second transport roller 52 (discharge roller). The positions of the first transport roller 51 and the second transport roller 52 can be switched between a transport position in which the paper 2 is transported in the first transport path 1a and a retracted position away from the first transport path 1a.

[0045] As shown in Figure 3, when the operating mode is set to normal mode, the roller positions are set to a first position state in which the first conveyor roller 51 is in the conveying position and the second conveyor roller 52 is in the retracted position. In other words, the first conveyor roller 51 is the conveyor roller used in normal mode.

[0046] As shown in Figure 4, when the operating mode is set to test mode, the roller position state is set to a second position state in which the second conveyor roller 52 is in the conveying position and the first conveyor roller 51 is in the retracted position. In other words, the second conveyor roller 52 is the conveyor roller used in test mode.

[0047] Figures 2 to 4 show an example in which the transport position and retracted position of the first transport roller 51 and the second transport roller 52 are switched by a rotation method. Alternatively, the first transport roller 51 and the second transport roller 52 may be moved in the vertical direction (Z-axis direction: perpendicular to the transport surface) to switch the transport position and retracted position. Typically, the first transport roller 51 and the second transport roller 52 can be switched between the transport position and the retracted position by any method, as long as their positions can be switched between the transport position and the retracted position.

[0048] The switching of the positions of the first conveyor roller 51 and the second conveyor roller 52 is achieved by a moving mechanism that moves the first conveyor roller 51 and the second conveyor roller 52. The moving mechanism includes, for example, a motor as a drive source, a rotation mechanism (in the case of a rotary type: a turntable, gears, etc.), a linear movement mechanism (in the case of linear movement: a slider, rack and pinion, etc.).

[0049] On the opposite side of the conveying path 1 from the first conveying roller 51 and the second conveying roller 52, a common roller 53 is positioned that is used in common by both the first conveying roller 51 and the second conveying roller 52.

[0050] When the operating mode is set to normal mode, the paper 2 is caught between the first transport roller 51 located at the transport position and the common roller 53, and transported downstream in the transport direction. On the other hand, when the operating mode is set to test mode, the paper 2 is caught between the second transport roller 52 located at the transport position and the common roller 53, and transported downstream in the transport direction.

[0051] The first transport roller 51 and the second transport roller 52 are positioned on the side of the paper 2 that has been printed (in the case of double-sided printing, the side that has been most recently printed). On the other hand, the common roller 53 is positioned on the side of the paper 2 that is opposite to the side that has been printed (in the case of double-sided printing, the side that has been most recently printed).

[0052] Furthermore, in this embodiment, the common roller 53 is a driven roller, while the first conveyor roller 51 and the second conveyor roller 52 are driven rollers that rotate in accordance with the rotation of the driven roller. Alternatively, the first conveyor roller 51 and the second conveyor roller 52 may be driven rollers, and the common roller 53 may be a driven roller. Or, both the common roller 53 side and the first conveyor roller 51 and second conveyor roller 52 side may be driven rollers.

[0053] <Operation Description> Next, the operation of the inkjet printing device 100 will be described while explaining the processing of the control unit 10.

[0054] Figures 5 and 6 are flowcharts showing the processing of the control unit 10 in the inkjet printing device 100.

[0055] The control unit 10 first determines whether a user has entered an instruction to switch the operating mode via the input unit 60 (ST101). If the user has not entered an instruction to switch the operating mode (NO in ST101), the control unit 10 determines whether the current operating mode is the normal mode (ST102).

[0056] If the current operating mode is normal mode (ST102 YES), the control unit 10 proceeds to ST118, which will be described later. On the other hand, if the current operating mode is test mode (ST102 NO), the control unit 10 proceeds to ST109, which will be described later.

[0057] In ST101, if the user inputs an instruction to switch the operating mode (YES in ST101), the control unit 10 determines whether the current operating mode is normal mode (ST103).

[0058] If the operating mode is in normal mode when an instruction to switch the operating mode is input (YES in ST103), the control unit 10 switches the operating mode from normal mode to test mode (ST104). In this mode switch, first the control unit 10 rotates the rotating plate 54 clockwise by a predetermined angle θ° to switch the connection state of the transport path 1 from a first connection state to a second connection state (ST105) (see Figure 4).

[0059] Next, the control unit 10 moves the first transport roller 51 from the transport position to the retracted position, and moves the second transport roller 52 from the retracted position to the transport position, thereby switching the positional state of the first transport roller 51 and the second transport roller 52 from the first position to the second position (ST106) (see Figure 4).

[0060] Next, the control unit 10 switches the temperature change state from a temperature change restricted state, where temperature changes of the heater 41 are restricted, to a temperature change permitted state, where temperature changes of the heater 41 are permitted (ST107). Note that the order in which ST105 (switching the connection state), ST106 (switching the position state), and ST107 (switching the temperature change state) are executed does not matter.

[0061] Next, the control unit 10 determines whether a user has entered an instruction to switch the operating mode via the input unit 60 (ST108). If an instruction to switch the operating mode has entered (YES in ST108), the control unit 10 returns to ST103.

[0062] On the other hand, if no instruction to switch the operating mode is input (NO in ST108), the control unit 10 determines whether an instruction to change the temperature of the heater 41 and the temperature to be changed have been input via user operation through the input unit 60 (ST109).

[0063] If the user does not input an instruction to change the temperature of the heater 41 or the temperature to be changed (ST109 NO), the control unit 10 skips ST110 and proceeds to ST111. On the other hand, if the user inputs an instruction to change the temperature of the heater 41 or the temperature to be changed (ST109 YES), the control unit 10 changes the set temperature of the heater 41 according to the instruction (ST110) and proceeds to the next ST111.

[0064] In ST111, the control unit 10 determines whether a user has entered an instruction to execute the print process on paper 2 in test mode via the input unit 60. If no instruction to execute the print process is entered (ST111 NO), the control unit 10 returns to ST108. On the other hand, if an instruction to execute the print process is entered (ST111 YES), the control unit 10 executes the print process in test mode (ST112), and then returns to ST108.

[0065] In the test mode printing process, first, an image prepared in advance for test mode is printed onto paper 2 by the print unit 30. After printing, paper 2 is dried by the heat of a heater 41 whose temperature is adjusted by the user.

[0066] After drying, the paper 2 is sandwiched between the common roller 53 and the second transport roller 52 located at the transport position in the first transport path 1a and transported downstream in the transport direction, and discharged to the discharge tray via the first transport path 1a and the third transport path 1c.

[0067] The user removes the paper 2 from the output tray and checks the degree of dryness of the ink (and paper 2) on the paper 2 by touch and visual inspection. If the ink (and paper 2) is not completely dry, the user increases the set temperature of the heater 41 through user operation via the input unit 60 (see ST109). Conversely, if the ink (and paper 2) is too dry, the user decreases the set temperature of the heater 41 through user operation via the input unit 60 (see ST109).

[0068] Subsequently, the user performs the print process in test mode again (ST111), and again checks the dryness of the ink (and paper 2) on paper 2 by touch and visual inspection. The user repeats this process until the ink (and paper 2) is dry to an appropriate degree.

[0069] This ensures that the heater 41 is set to an appropriate temperature. Consequently, it prevents the ink from remaining wet due to the heater 41 being set too low (especially in normal mode). On the other hand, it prevents the ink and paper 2 from being damaged due to the heater 41 being set too high, and also reduces unnecessary power consumption by the heater 41 (especially in normal mode).

[0070] In this explanation, we have described the case where the user checks the dryness of the ink (and paper 2) and adjusts the temperature of the heater 41. On the other hand, the control unit 10 may automatically check the dryness of the ink (and paper 2), and the control unit 10 may automatically adjust the temperature of the heater 41.

[0071] In this case, sensors (for example, humidity sensors) for detecting the dryness of the ink (and paper 2) are provided in the first transport path 1a, the third transport path 1c, etc. Based on the signals detected by these sensors, the control unit 10 checks the dryness of the ink (and paper 2) and adjusts the temperature of the heater 41 based on the dryness.

[0072] In ST103, if the operating mode at the time of input for switching the operating mode is test mode (NO in ST103), the control unit 10 switches the operating mode from test mode to normal mode (ST113). In this mode switching, first, the control unit 10 rotates the rotating plate 54 counterclockwise by a predetermined angle θ° to switch the connection state of the transport path 1 from the second connection state to the first connection state (ST114) (see Figure 3).

[0073] Next, the control unit 10 moves the second transport roller 52 from the transport position to the retracted position, and moves the first transport roller 51 from the retracted position to the transport position, thereby switching the position of the first transport roller 51 and the second transport roller 52 from the second position to the first position (ST115).

[0074] Next, the control unit 10 switches the temperature change state from a temperature change permitted state, where temperature changes of the heater 41 are allowed, to a temperature change restricted state, where temperature changes of the heater 41 are restricted (ST116). Note that the order in which ST114 (switching the connection state), ST115 (switching the position state), and ST116 (switching the temperature change state) are executed does not matter.

[0075] Next, the control unit 10 determines whether a user has entered an instruction to switch the operating mode via the input unit 60 (ST117). If an instruction to switch the operating mode has entered (YES in ST117), the control unit 10 returns to ST103.

[0076] On the other hand, if no instruction to switch the operating mode is input (NO in ST117), it is determined whether an instruction to start printing in normal mode has been input via user operation through the input unit 60 (ST118). If no instruction to start printing in normal mode has been input (NO in ST118), the control unit 10 returns to ST117.

[0077] On the other hand, if a command to start printing in normal mode is input (YES in ST118), the control unit 10 calculates a second ink occupancy rate on the paper 2 to be printed and stores this value in memory (ST119).

[0078] Next, the control unit 10 reads from memory the first occupancy rate of the ink portion on the paper 2 that was printed in the previous step.

[0079] Here, the occupancy rate is typically the ratio of the total area of ​​the ink portion (image portion) to the total area of ​​the paper 2 (printing rate). Alternatively, the paper 2 may be divided into multiple regions, and the occupancy rate for each region may be determined. In this case, the highest occupancy rate among the regions (i.e., the occupancy rate of the region with the highest density and slowest drying time) may be used as the occupancy rate of the ink portion on the corresponding paper 2.

[0080] After reading the first occupancy rate from memory, the control unit 10 then calculates the rate of change of the second occupancy rate relative to the first occupancy rate (ST121). Next, the control unit 10 determines whether this rate of change is greater than or equal to a predetermined threshold (for example, ±10%) (ST122).

[0081] If the rate of change is below the threshold (ST122 NO), the control unit 10 proceeds to ST127. On the other hand, if the rate of change is above the threshold (ST123 YES), the control unit 10 temporarily stops the print process in normal mode (ST123). Then, the control unit 10 recommends to the user via the display unit 70 that the operation mode be switched from normal mode to test mode (ST124).

[0082] Figure 7 shows an example of an image displayed on the screen of the display unit 70 to recommend that the user switch to test mode. In the example shown in Figure 7, the words "Switching to test mode and adjusting the temperature of the heater 41 is recommended." and "Do you want to switch to test mode?" are displayed on the screen, and below these words, "YES" and "NO" buttons are displayed.

[0083] In this explanation, we described an example where the user is encouraged to switch to test mode via video from the display unit 70 (notification unit). However, the user may also be encouraged to switch to test mode via audio from the speaker (notification unit). Typically, this recommendation can be made in any way that is recognizable to the user.

[0084] After recommending a change in operating mode, the control unit 10 determines whether the user has entered an instruction to change the operating mode in response to the recommendation (ST125). If the user has entered an instruction to change the operating mode in response to the recommendation (for example, if the "YES" button in Figure 7 is touched) (YES in ST125), the control unit 10 returns to ST103.

[0085] On the other hand, if the user does not input an instruction to switch operating modes despite being recommended to do so (for example, if the "NO" button in Figure 7 is touched) (NO in ST125), the control unit 10 resumes printing in normal mode (ST126).

[0086] Next, the control unit 10 determines whether the print process in normal mode has finished (ST127). If the print process has not finished (NO in ST127), the control unit 10 returns to ST119. On the other hand, if the print process has finished (YES in ST127), the control unit 10 returns to ST117.

[0087] In normal printing mode, first, the user's desired image is printed onto the paper 2 in the printing unit 30, and then the printed paper 2 is dried by the heat of the heater 41.

[0088] After drying, the paper 2 is sandwiched between the common roller 53 and the first transport roller 51 located at the transport position in the first transport path 1a and transported downstream in the transport direction, and discharged to the discharge tray via the first transport path 1a and the second transport path 1b.

[0089] If the second ink area (image area) occupancy rate on the paper 2 to be printed this time differs significantly from the first ink area (image area) occupancy rate on the previously printed paper 2 (for example, ±10%), the printing process in normal mode is temporarily stopped (see ST122 YES~ST123). Then, for example, an image like the one shown in Figure 7 is displayed on the screen of the display unit 70, and switching to test mode is recommended (ST124).

[0090] If the user does not accept this recommendation and wishes to keep the operating mode in normal mode, for example, they will touch the "NO" button in Figure 7 (see NO in ST125). Then, the printing process will resume with the operating mode remaining in normal mode (see ST126).

[0091] On the other hand, if the user accepts this recommendation and switches the operating mode from normal mode to test mode, they touch the "YES" button in Figure 7, for example (see YES in ST125). Then the operating mode is switched from normal mode to test mode (see ST104).

[0092] If the second occupancy rate in this test is higher than the first occupancy rate in the previous test, that is, if the ink is not drying easily, in test mode, the user can set the heater 41 to a higher temperature through user operation via the input unit 60 (see ST110). This prevents the heater 41 temperature from being set too low, which would result in the ink not drying properly (especially in normal mode).

[0093] On the other hand, if the second occupancy rate in this test is lower than the first occupancy rate in the previous test, that is, if the ink dries out too quickly, the user can lower the heater 41's temperature setting through user operation via the input unit 60 in test mode (see ST110). This prevents the heater 41 from being set too high and damaging the ink or paper 2, and also reduces unnecessary power consumption by the heater 41 (especially in normal mode).

[0094] <Effect, etc.> As described above, the inkjet printing apparatus in this embodiment has two operating modes: a normal mode and a test mode for checking the degree of drying, and these two modes can be switched between. In the normal mode, the first transport path 1a and the second transport path 1b are connected by the rotation of the rotating plate 54 (first connection state). On the other hand, in the test mode, the first transport path 1a and the third transport path 1c are connected by the rotation of the rotating plate 54 (second connection state).

[0095] The test mode is a mode for checking the dryness of the ink (and paper 2), so there may be cases where the ink on paper 2 is not yet dry. However, in test mode, paper 2 with undried ink is discharged to the output tray via the third transport path 1c. In other words, paper 2 with undried ink in test mode does not pass through the second transport path 1b used in normal mode. Therefore, it is possible to prevent the second transport path 1b from becoming contaminated with ink. As a result, in normal mode, it is possible to prevent subsequent sheets of paper 2 from being contaminated by ink contamination on transport path 1.

[0096] Furthermore, in this embodiment, in normal mode, the first conveyor roller 51 is positioned in the conveying position and the second conveyor roller 52 is positioned in the retracted position (first position state). On the other hand, in test mode, the second conveyor roller 52 is positioned in the conveying position and the first conveyor roller 51 is positioned in the retracted position (second position state).

[0097] As described above, the test mode is a mode for checking the dryness of the ink (and paper 2), so the ink on paper 2 may not be dry. However, in test mode, paper 2 with undried ink is sandwiched between the second transport roller 52 and the common roller 53 and transported downstream in the transport direction. In other words, paper 2 with undried ink in test mode does not come into contact with the first transport roller 51 used in normal mode. Therefore, it is possible to prevent the first transport roller 51 from becoming contaminated with ink. As a result, in normal mode, it is possible to prevent subsequent sheets of paper 2 from being contaminated by ink contamination on the first transport roller 51.

[0098] Furthermore, in this embodiment, the heater 41 is configured to be temperature-adjustable, and in test mode, the user (or the control unit 10 automatically) can adjust the temperature of the heater 41 while checking the degree of ink dryness to set the temperature of the heater 41 to an appropriate temperature.

[0099] This prevents the heater 41 from being set too low, which could cause the ink to remain wet (especially in normal mode). On the other hand, it also prevents the heater 41 from being set too high, which could damage the ink or paper 2, and reduces unnecessary power consumption by the heater 41 (especially in normal mode).

[0100] Furthermore, in this embodiment, in normal mode, if the second ink occupancy rate on the paper 2 to be printed this time differs significantly from the first ink occupancy rate on the previously printed paper 2 (for example, ±10%), the user is recommended to switch from normal mode to test mode.

[0101] In other words, when the ink coverage changes significantly, the current temperature of the heater 41 may not be suitable for drying the ink. Therefore, in such cases, this embodiment recommends that the user switch the operating mode from normal mode to test mode and change the temperature of the heater 41 in this test mode.

[0102] If the user follows this recommendation, the heater 41 will be set to an appropriate temperature, thus resolving issues such as ink not drying due to low temperatures, damage to the ink and paper 2 due to high temperatures, and power consumption of the heater 41.

[0103] <Various variations> Next, various modifications of this technology will be described.

[0104] Figures 8 and 9 show other examples of the first and second conveyor rollers. Figure 8 shows the operation in normal mode, and Figure 9 shows the operation in test mode.

[0105] As shown in Figures 8 and 9, the first conveying path 1a is provided with a pair of first conveying rollers 55 and a pair of second conveying rollers 56. The pair of first conveying rollers 55 are provided downstream of the pair of second conveying rollers 56. Alternatively, the pair of second conveying rollers 56 may be provided downstream of the pair of first conveying rollers 55.

[0106] The pair of first conveyor rollers 55 are positioned to sandwich the first conveyor path 1a from both sides in the vertical direction (direction perpendicular to the conveyor path surface: Z-axis direction). Of the pair of first conveyor rollers 55, one first conveyor roller 55a is a driven roller, and the other first conveyor roller 55b is a driven roller.

[0107] Similarly, the pair of second conveyor rollers 56 are positioned to sandwich the first conveyor path 1a from both sides in the vertical direction (direction perpendicular to the conveyor path surface: Z-axis direction). Of the pair of second conveyor rollers 56, one second conveyor roller 56a is a driven roller, and the other second conveyor roller 56b is a driven roller.

[0108] The pair of first conveyor rollers 55 are independently movable in the vertical direction. Similarly, the pair of first conveyor rollers 56 are also independently movable in the vertical direction.

[0109] As shown in Figure 8, when the operating mode is switched from test mode to normal mode, one of the pair of first conveyor rollers 55, the first conveyor roller 55a, is moved downward (to the conveying position), and the other first conveyor roller 55b is moved upward (to the conveying position). At the same time, one of the pair of second conveyor rollers 56, the second conveyor roller 56a, is moved upward (to the retracted position), and the other second conveyor roller 56b is moved downward (to the retracted position).

[0110] In normal mode, a pair of first transport rollers 55 are positioned at the transport location, and these first transport rollers 55 rotate while gripping the paper 2 from both sides of the paper surface, thereby transporting the paper 2 downstream in the transport direction.

[0111] On the other hand, as shown in Figure 9, when the operating mode is switched from normal mode to test mode, one of the pair of first conveyor rollers 55, the first conveyor roller 55a, is moved upward (to the retracted position), and the other first conveyor roller 55b is moved downward (to the retracted position). Also, at this time, one of the pair of second conveyor rollers 56, the second conveyor roller 56a, is moved downward (to the conveying position), and the other second conveyor roller 56b is moved upward (to the conveying position).

[0112] In test mode, a pair of second transport rollers 56 are positioned at the transport location, and these two second transport rollers 56 grip the paper 2 from both sides of the paper surface and rotate, thereby transporting the paper 2 downstream in the transport direction.

[0113] The same effects and advantages as those of the embodiments described above are also achieved in the other examples shown in Figures 8 and 9.

[0114] In this case, if the inkjet printer 100 is capable of double-sided printing, printing on both sides may be permitted only in the normal mode, of the normal mode and the test mode. In this case, the control unit 10 permits printing on both sides in the normal mode, while restricting printing on both sides in the test mode.

[0115] This prevents the undried ink on the paper 2 in test mode from passing through the inversion path of the inversion unit. This prevents the inversion path from becoming contaminated with ink, and prevents the paper 2 from becoming contaminated with ink when passing through the inversion path in normal mode. It also prevents undried ink from adhering to the common roller 53 in test mode.

[0116] In the above explanation, paper 2 was used as an example of a recording medium on which an image is formed. On the other hand, the recording medium may be metal, resin, cloth, wood, etc., and typically, any medium on which an image can be formed is acceptable.

[0117] In the above explanation, ink printing was used as an example of an image forming process. On the other hand, the image forming process may also be laser printing, and typically, any process that forms an image on a recording medium is acceptable. [Explanation of symbols]

[0118] 1…Conveyor path 1a...First transport path 1b...Second transport path 1c... Third transport path 2… Paper 10…Control Unit 40...Drying section 41… Heater 50…Discharge section 51, 55... First conveyor roller 52, 56... Second conveyor roller 53... Common Laura 54... Rotating plate 100... Inkjet printer

Claims

1. A drying unit that applies heat to a recording medium that has undergone image formation processing to dry the image and fix the image to the recording medium, A transport path including a first transport path through which the dried recording medium is transported, and a second transport path and a third transport path that branch off from the first transport path downstream in the transport direction of the recording medium in the first transport path, A branching mechanism capable of switching between a first connection state connecting the first transport path and the second transport path, and a second connection state connecting the first transport path and the third transport path, A control unit that switches between the first connection state and the second connection state in accordance with the switching between normal mode and a test mode for checking the dryness of the image. An image forming apparatus comprising the following:

2. An image forming apparatus according to claim 1, A first transport roller and a second transport roller are provided on the first transport path and are capable of switching between a transport position for transporting the recording medium and a retracted position away from the first transport path. An image forming apparatus further comprising:

3. An image forming apparatus according to claim 2, The control unit switches between a first position state in which the first transport roller is in the transport position and the second transport roller is in the retracted position, and a second position state in which the second transport roller is in the transport position and the first transport roller is in the retracted position, depending on the switching between the normal mode and the test mode. Image forming apparatus.

4. An image forming apparatus according to claim 3, The control unit switches between the normal mode and the test mode based on a mode switching instruction input by the user. Image forming apparatus.

5. An image forming apparatus according to claim 3, The control unit can change the temperature of the heat applied to the recording medium by controlling the drying unit. Image forming apparatus.

6. An image forming apparatus according to claim 5, The control unit changes the temperature based on a temperature change instruction input by the user in response to the user's confirmation of the dryness of the image in the recording medium processed in the test mode. Image forming apparatus.

7. An image forming apparatus according to claim 5, The control unit allows the temperature to be changed in the test mode and restricts the temperature to be changed in the normal mode. Image forming apparatus.

8. An image forming apparatus according to claim 5, The image forming process can be performed on both the front and back surfaces of the recording medium. The control unit permits image forming processing on both sides in the normal mode and restricts image forming processing on both sides in the test mode. Image forming apparatus.

9. An image forming apparatus according to claim 5, The control unit executes a process for switching between the normal mode and the test mode based on the rate of change between the first occupancy rate of the image portion in the recording medium that was subjected to image forming processing in the previous instance and the second occupancy rate of the image portion in the recording medium that is subjected to image forming processing in the current instance. Image forming apparatus.

10. An image forming apparatus according to claim 9, It further comprises a notification unit that notifies the user of predetermined matters, The control unit recommends to the user, via the notification unit, that the user switch from the normal mode to the test mode based on the rate of change. Image forming apparatus.

Images