Sheet conveying device

Abstract

To provide a sheet conveying device capable of maintaining stable paper feeding capacity.SOLUTION: A printer comprises: an MP tray 41 in which a high friction member 58 is provided on a sheet placement face 44a; a sheet presence / absence sensor 47 whose output is changed by presence / absence of a sheet placed on the sheet placement face 44a; an MP paper-feeding roller 51 for feeding the sheet by turning in a state of coming into contact with the sheet placed on the MP tray 41, that is provided at a position corresponding to the high friction member 58 of the sheet placement face 44a; a temperature sensor whose output is changed according to an environmental temperature; and a memory. Then, the execution of cleaning control for rotating the MP paper-feeding roller 51 in a state where the MP paper-feeding roller 51 and the high friction member 58 of the MP tray 41 come into contact with each other is determined based on the output of the sheet presence / absence sensor 47, the output of the temperature sensor, and a paper-feeding counter value stored in the memory.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a sheet transport device that transports a sheet. [Background technology]

[0002] In some sheet transport devices that use a pickup roller for paper feeding, in order to ensure stable paper feeding over a long period of time, when a predetermined condition is met, the pickup roller is rotated while being in contact with a high-friction member provided in a paper feed tray, thereby cleaning the pickup roller. In the following patent document, an example of such a sheet transport device is disclosed, in which the predetermined condition is that the number of fed sheets exceeds a certain number, and because the ease with which paper dust adheres varies depending on the type of sheet, the value counted for each separation of a sheet is weighted depending on the type of sheet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-64845 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the susceptibility of paper dust to adhesion varies not only depending on the type of sheet but also on the environment in which the device is placed, so in a sheet conveying device used in a variety of environments, there is a risk that weighting based on the type of sheet alone will not always be able to provide stable paper feeding capabilities.

[0005] The present invention has been made in consideration of the above, and aims to provide a sheet conveying device that is capable of maintaining stable sheet feeding performance for various sheet types and usage environments. [Means for solving the problem]

[0006] In order to achieve the above object, the sheet conveying device of the present application comprises a sheet placing section having a high-friction member provided on the sheet placing surface, a sheet presence / absence sensor whose output changes depending on whether a sheet is placed on the sheet placing surface, a paper feed roller provided at a position corresponding to the high-friction member on the sheet placing section and which feeds a sheet by rotating while in contact with the sheet placed on the sheet placing section, a temperature sensor whose output changes depending on the ambient temperature, a memory, and a control unit, wherein the control unit is capable of performing cleaning control to rotate the paper feed roller while the paper feed roller is in contact with the high-friction member of the sheet placing section, and determines whether to perform the cleaning control based on the output of the sheet presence / absence sensor, the output of the temperature sensor, and a value related to the number of times a sheet has been fed stored in the memory. [Effects of the Invention]

[0007] According to the sheet transport device having the above configuration, cleaning control is performed to rotate the sheet feed roller while keeping the sheet feed roller in contact with the high-friction member, based on the presence or absence of sheets placed on the sheet placement section, the ambient temperature, and a value related to the number of sheet feeds, thereby making it possible to maintain stable sheet feeding performance for various sheet types and usage environments. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side cross-sectional view showing a main part of a printer according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional side view of the main part of the printer with the MP tray open. [Figure 3] FIG. 2 is a block diagram showing the electrical configuration of the printer. [Figure 4] 10 is a flowchart of a printing process according to the present embodiment. [Figure 5] 10 is a flowchart of a printing process according to the present embodiment. [Figure 6] 10 is a flowchart of a printing process according to the present embodiment. [Figure 7] 10 is a flowchart of a printing process according to the present embodiment. [Figure 8] 10 is a flowchart of a printing process according to the present embodiment. [Figure 9] 10 is a flowchart of a printing process according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment in which the sheet conveying device according to the present application is embodied in a printer, which is an image forming apparatus, will be described below with reference to the drawings. FIG. 1 is a side cross-sectional view of the essential parts of the printer 1 of this embodiment. Note that, although the following description will be directed to an embodiment in which the sheet conveying device is embodied in the printer 1, the "sheet conveying device" can be embodied not only in printing devices such as printers (e.g., laser printers and inkjet printers), but also in various devices having a function of conveying sheets, such as copiers, facsimile machines, and multifunction devices having both printer and scanner functions. Furthermore, the "sheet" is not limited to paper sheets as a recording medium, but also includes transparencies, films, etc.

[0010] [Overall printer configuration] The printer 1 according to this embodiment is an electrophotographic monochrome laser printer that prints a desired image on a sheet 3. However, the printer 1 may also be a color laser printer. The printer 1 includes a main body housing 2, a feeder unit (an example of a sheet conveying device) 4 for feeding sheets 3 as recording media within the main body housing 2, and an image forming unit 5 for forming an image on the fed sheets 3. Below, of the above components, the main body housing 2 and the feeder unit 4 will be described in more detail.

[0011] (Main body) In the main body housing 2, an attachment / detachment opening 6 is formed in one side wall for attaching and detaching a process cartridge 18, which is part of the image forming unit 5, and a front cover 7 is provided for opening and closing the attachment / detachment opening 6.

[0012] The front cover 7 is rotatably supported by a cover shaft (not shown) inserted into its lower end. As a result, when the front cover 7 is closed around the cover shaft, the attachment / detachment opening 6 is closed by the front cover 7, as shown in Fig. 1, and when the front cover 7 is opened (tilted) around the cover shaft as a fulcrum, the attachment / detachment opening 6 is opened, and the process cartridge 18 can be attached to or detached from the main body casing 2 through the attachment / detachment opening 6.

[0013] In the following description, the side of the printer 1 and the process cartridge 18 where the front cover 7 is provided will be referred to as the "front side," and the opposite side will be referred to as the "rear side." Also, when looking at the printer 1 from the front side, the right side (the back side of the paper) will be referred to as the "right side," and the opposite side (the front side of the paper) will be referred to as the "left side."

[0014] A user I / F 63 (see FIG. 3) (an example of a display unit) for providing information to a user and accepting user operations is disposed on the top surface of the main body housing 2. The user I / F 63 is, for example, a touch panel that also functions as a display.

[0015] A temperature sensor 68 (see FIG. 3) is also disposed inside the main housing 2. The temperature sensor 68 is fixed to the inside of the right side wall that defines the attachment / detachment opening 6 of the main housing 2, and its output changes according to the detected temperature. A slit (not shown) is formed in the right side wall of the main housing 2 near the temperature sensor 68. Therefore, although the temperature sensor 68 is disposed inside the main housing 2, outside air enters the inside of the main housing 2 through the slit, so the temperature sensor 68 detects the ambient temperature of the environment in which the printer 1 is placed, and its output changes according to the ambient temperature.

[0016] (feeder section) The feeder section 4 includes a paper feed tray 8 that is removably attached to the bottom of the main body housing 2, a separation roller 9 and a separation pad 10 that are provided above the front end of the paper feed tray 8, and a paper feed roller 11 that is provided behind the separation roller 9 (upstream of the separation pad 10 in the conveying direction of the sheet 3).

[0017] The feeder unit 4 is also provided with a paper dust removal roller 12 arranged opposite the separation roller 9 above and in front of it (downstream of the separation roller in the conveying direction of the sheet 3), and an opposing roller 13 arranged opposite the paper dust removal roller 12. A first conveying path 14 for the sheet 3 is formed in a U-shape that is folded back toward the rear from near the position of the paper dust removal roller 12, and further downstream in the conveying direction, below the process cartridge 18, is provided with a registration roller 15 consisting of a pair of upper and lower rollers.

[0018] Further, a first sensor 21 that detects passage of the sheet 3 (more precisely, the leading edge of the sheet) on the first conveying path 14 is disposed upstream of the registration rollers 15 in the sheet conveying direction. Similarly, a second sensor 22 that detects passage of the sheet 3 (more precisely, the leading edge of the sheet) on the first conveying path 14 is disposed downstream of the registration rollers 15 in the sheet conveying direction.

[0019] A paper pressure plate 16 on which sheets 3 can be placed in a stack is provided inside the paper feed tray 8. The rear end of this paper pressure plate 16 is supported so as to be swingable, allowing the front end to move up and down.

[0020] Furthermore, a lever 17 for lifting the front end of the paper pressure plate 16 is provided at the front end of the paper feed tray 8. The rear end of this lever 17 is swingably supported by a lever shaft (not shown) below the front end of the paper pressure plate 16, and the front end abuts against the front end of the underside of the paper pressure plate 16. As a result, when a rotational driving force in the counterclockwise direction in the figure is input to the lever shaft, the lever 17 rotates around the lever shaft as a fulcrum, and the front end of the lever 17 lifts the front end of the paper pressure plate 16.

[0021] When the front end of the paper pressure plate 16 is lifted, the topmost sheet 3 on the paper pressure plate 16 is pressed against the paper feed roller 11, and as the paper feed roller 11 rotates, the paper starts to be fed toward the separation position between the separation roller 9 and the separation pad 10.

[0022] The sheets 3 sent by the paper feed roller 11 toward the separation position are reliably separated and fed one by one when they are sandwiched between the separation roller 9 and the separation pad 10 by the rotation of the separation roller 9. The fed sheets 3 are folded back along the U-shaped first transport path 14. More specifically, the fed sheets 3 are first transported diagonally upward and forward by the separation roller 9 and the separation pad 10, and then pass between the paper dust removal roller 12 and the opposing roller 13, where paper dust is removed, and then transported to the registration rollers 15.

[0023] A media type detection sensor 67 (an example of an acquisition unit) that detects the media type of the sheet 3 transported on the first transport path 14 is disposed upstream of the registration rollers 15 in the sheet transport direction. The media type detection sensor 67 includes a capacitance sensor and a size sensor. The capacitance sensor detects the thickness of the sheet 3 transported on the first transport path 14, and the size sensor detects the size of the sheet 3 transported on the first transport path 14. In this way, the media type detection sensor 67 detects the media type of the sheet 3 transported on the first transport path 14. For example, if the capacitance sensor detects that the thickness of the sheet 3 transported on the first transport path 14 is equal to or greater than a predetermined thickness and the size sensor detects that the size of the sheet 3 transported on the first transport path 14 is postcard size, the media type detection sensor 67 detects that the media type of the sheet 3 transported on the first transport path 14 is postcard size. Furthermore, when the capacitance sensor detects that the thickness of the sheet 3 transported on the first transport path 14 is equal to or greater than a predetermined thickness and the size sensor detects that the size of the sheet 3 transported on the first transport path 14 is not postcard size, the media type detection sensor 67 detects that the media type of the sheet 3 transported on the first transport path 14 is cardboard. When the capacitance sensor detects that the thickness of the sheet 3 transported on the first transport path 14 is less than a predetermined thickness and the size sensor detects that the size of the sheet 3 transported on the first transport path 14 is not postcard size, the media type detection sensor 67 detects that the media type of the sheet 3 transported on the first transport path 14 is plain paper.

[0024] The registration rollers 15 are made up of a pair of opposing rollers, one above the other, and correct the orientation of the sheet 3 before transporting it toward the transfer position (the nip position between the photosensitive drum and the transfer roller, where the toner image on the photosensitive drum is transferred to the sheet 3) of the image forming unit 5. In this way, the sheet 3 fed from the paper feed tray 8 is transported to the transfer position of the image forming unit 5, whereby the toner image on the photosensitive drum is transferred to the sheet 3 fed from the paper feed tray 8. In this way, the desired image is printed on the sheet 3.

[0025] Furthermore, not only the sheet 3 fed from the paper feed tray 8 but also the sheet 3 fed from an MP (multipurpose) tray (an example of a sheet placing section) (an example of a manual feed tray) 41 is transported to the transfer position of the image forming unit 5 by the registration rollers 15, and the toner image on the photosensitive drum is transferred onto the sheet 3 fed from the MP tray 41, thereby printing a desired image. Note that the printer 1 is provided with a transport path (a second transport path 54 described later) for the sheet 3 from the MP tray 41 so as to merge with the first transport path 14 from the paper feed tray 8 to the image forming unit 5.

[0026] The multi-purpose mechanism 42 including the MP tray 41 will be described below. Note that Fig. 2 is a side cross-sectional view of the main part showing the MP tray 41 in an open state. In addition to the paper feed mechanism that transports the sheet 3 from the paper feed tray 8 to the transfer position of the image forming unit 5 via the first transport path 14, the printer 1 also has a multi-purpose mechanism 42 that transports the sheet 3 to the transfer position by manual insertion from the front side of the printer 1. In other words, the multi-purpose mechanism 42 is part of the feeder unit 4.

[0027] A rectangular opening 40 is formed through the front cover 7, and an MP tray 41 is provided to cover this opening. Specifically, the MP tray 41 is configured to include a cover section 43, which serves as the front wall of the main body housing 2, and a tray section 44 on which sheets 3 to be manually fed are stacked. As shown in FIG. 2, the lower end of the cover section 43 is pivotally supported by a rotation shaft 43a relative to the main body housing 2, and is openable and closable around the rotation shaft 43a. The cover section 43 is locked with its inner surface facing upward, and the tray section 44 is provided on this inner surface. As shown in FIG. 2, when the MP tray 41 is open, the rotation shaft 43a side of the tray section 44 (the side where the sheet 3 is inserted) is tilted downward. When the MP tray 41 is open, sheets 3 are stacked on a sheet placement surface 44a, which is the upper surface of the tray section 44. A sheet presence / absence sensor 47 is provided on the sheet placement surface 44a. The output of the sheet presence / absence sensor 47 changes depending on whether or not a sheet is placed on the sheet placement surface 44a.

[0028] The MP tray 41 is also provided with a guide mechanism 49 having a pair of guide ribs 48 (only the left one is shown in FIGS. 1 and 2) that, when the MP tray 41 is open, sandwich both widthwise ends of the sheets 3 loaded on the tray section 44 to guide their conveyance. The pair of guide ribs 48 are slidable between positions where they approach each other and positions where they are separated, so that the MP tray 41 can stack sheets 3 of any size in layers.

[0029] This guide mechanism 49 is located behind the upper end of the folded tray section 44 (in the space above the multi-purpose mechanism 42) when the MP tray 41 is closed (see Figure 1), and when the MP tray 41 is opened (see Figure 2), it slides along the guide groove 50 and is positioned at the rear end of the tray section 44.

[0030] 2, the multi-purpose mechanism 42 includes an MP paper feed roller (an example of a paper feed roller) 51, an MP separation roller 52, and an MP separation pad 53 that faces and is pressed against the MP separation roller 52. With the MP separation roller 52 and the MP separation pad 53 in contact with each other, the MP separation pad 53 is pressed against the MP separation roller 52 by the biasing force of a biasing member (not shown). In other words, the multi-purpose mechanism 42 of this embodiment is a twin-roller system consisting of the MP paper feed roller 51 and the MP separation roller 52, with the MP paper feed roller 51 disposed on the MP tray 41 side and the MP separation roller 52 disposed behind it.

[0031] The uppermost sheet 3 stacked on the MP tray 41 is fed by the rotation of the contacting MP feed roller 51, and is sandwiched between the MP separation roller 52 and the MP separation pad 53, and then separated and fed one by one by their cooperation. The fed sheet 3 passes through the second transport path 54, enters the first transport path 14 at a junction X near the downstream end in the transport direction, and is sent to the registration roller 15 side.

[0032] More specifically, the partition member 55 sandwiched between the first transport path 14 and the second transport path 54 has a side cross-sectional shape that follows the U-shape of the first transport path 14, and has a shape that slopes downward from the junction X as it moves forward. In other words, the space on the upper surface side of the partition member 55 is a downwardly sloping space that widens downward as it moves forward from the junction X. A roller unit 56 that axially supports the MP feed roller 51 and MP separation roller 52 with the roller unit 56 exposed downward is provided in this downwardly sloping space, and as will be described later, the MP feed roller 51 moves up and down within this downwardly sloping space.

[0033] The MP separation pad 53 is disposed midway on the inclined upper surface of the partition member 55, and the MP separation roller 52 is disposed facing the MP separation pad 53 from above, with both being in a pressing state.

[0034] Next, a drive mechanism for conveying the sheets 3 stacked on the MP tray 41 by the MP feed roller 51 and the MP separation roller 52 will be briefly described.

[0035] The roller unit 56 is configured such that the MP feed roller 51 and the MP separation roller 52 are rotatably mounted on a common bearing member. Specifically, a gear is integrally and coaxially mounted on the side of the MP feed roller 51, and these are rotatably supported on the front end of the bearing member. Meanwhile, a gear is integrally and coaxially mounted on the side of the MP separation roller 52, and these are rotatably supported on the rear end of the bearing member. The gear of the MP feed roller 51 and the gear of the MP separation roller 52 are connected via another gear between them. As a result, when driving force is applied from the conveyance motor 66 (see FIG. 3), the MP separation roller 52 rotates, and the MP feed roller 51 rotates accordingly.

[0036] Furthermore, the roller unit 56 is configured so that the MP feed roller 51 side can swing around the MP separation roller 52. Specifically, the MP feed roller 51 can move between an elevated position (position shown in FIG. 2) where it is separated from the upper surface of the partition member 55, and a lowered position where the MP feed roller 51 can come into contact with the upper surface of the partition member 55. The switching between the elevated position and the lowered position is performed by a cam mechanism that operates when the solenoid 65 (see FIG. 3) is turned ON.

[0037] A high-friction member 58, such as cork, is provided below the MP feed roller 51. When the MP feed roller 51 is in the lowered position with no sheets 3 placed on the sheet placement surface 44a, the MP feed roller 51 comes into contact with the high-friction member 58. The MP feed roller 51 rotates while in contact with the high-friction member 58, thereby controlling cleaning of the MP feed roller 51. As described below, the MP feed roller 51 conveys the sheets 3 placed on the sheet placement surface 44a by rotating while in contact with the sheets 3. During this process, paper dust adhering to the surface of the sheets 3 and calcium carbonate, which is used as a pigment in sheets that require whiteness and smoothness, such as cardboard and high-quality paper, adhere to the MP feed roller 51. When paper dust and calcium carbonate adhere to the MP feed roller 51, the coefficient of friction of the MP feed roller 51 decreases, potentially making it impossible to stably convey the sheets 3. Therefore, by rotating the MP feed roller 51 while it is in contact with the high friction member 58, cleaning control of the MP feed roller is performed, in which the high friction member 58 removes paper dust and calcium carbonate adhering to the MP feed roller 51. This restores the friction coefficient of the MP feed roller 51, ensuring stable conveyance of the sheet 3.

[0038] Furthermore, by positioning the MP feed roller 51 in the lowered position while the sheets 3 are placed on the sheet placement surface 44a, the MP feed roller 51 can be rotationally driven to pick up the sheets 3 stacked on the sheet placement surface 44a of the MP tray 41. The operation of the drive mechanisms of the MP feed roller 51 and MP separation roller 52 when conveying the sheets 3 will now be briefly described.

[0039] First, before the solenoid is turned on (initial state), the home position is set. At the home position, the MP feed roller 51 is in a raised position separated from the sheet 3, and further, the MP feed roller 51 and the MP separation roller 52 are not given a driving force and are in an idle state.

[0040] When the solenoid is turned ON, a cam mechanism is activated, which moves the MP feed roller 51 to a lowered position where it abuts against the upper surface of the sheet 3 positioned on the upper surface of the partition member 55. Then, a gear mesh is established between an input gear to which the driving force of the transport motor 66 is input and the gears of the connected MP feed roller 51 and MP separation roller 52. Then, as the transport motor 66 is driven, the MP separation roller 52 is driven to rotate. Accordingly, the MP feed roller 51 is driven. As a result, feeding of the sheets 3 on the MP tray 41 begins, and the sheets 3 are separated one by one at a position where the MP separation roller 52 faces the MP separation pad 53, and the separated sheets 3 are transported toward the second transport path 54.

[0041] The sheet 3 is then transported to the second transport path 54, and further from the junction X through the first transport path 14 to the registration rollers 15. As described above, the registration rollers 15 correct the orientation of the sheet 3, and thereafter the sheet 3 is transported toward the transfer position of the image forming unit 5 by the drive of the registration rollers 15. Then, in the image forming unit 5, the toner image on the photosensitive drum is transferred onto the sheet 3, and the desired image is printed on the sheet 3.

[0042] [Printer electrical configuration] FIG. 3 shows the electrical configuration of the printer 1. The printer 1 includes a controller 61, a memory 62, a user I / F 63, a network I / F 64, a solenoid 65, a transport motor 66, a media type detection sensor 67, a temperature sensor 68, a first sensor 21, a second sensor 22, and a sheet presence sensor 47. Note that FIG. 3 shows only the configuration related to the transport of the sheet 3, and in reality, configuration related to, for example, printing is also included separately. These components are connected to a bus and can communicate with each other. Note that "I / F" is an abbreviation for Interface.

[0043] The controller 61 is composed of a CPU, an ASIC (Application Specific Integrated Circuit), and the like. The memory 62 is an embedded memory, such as a nonvolatile memory (ROM), flash memory, or HDD. The memory 62 stores programs executable by the controller 61. In this embodiment, the term primarily refers to the processing of the controller 61 in accordance with instructions written in the programs. In other words, the following descriptions refer to processing by the controller 61, such as "judging," "selecting," "calculating," "deciding," "identifying," "acquiring," "receiving," and "controlling." Note that "acquiring" is used as a concept that does not necessarily require a request. In other words, the process of the controller 61 receiving data without a request is also included in the concept of "the controller 61 acquiring data." Furthermore, "data" in this specification refers to a bit string that can be read by the controller. Data with essentially the same meaning but different formats are treated as the same data. The same applies to "information" in this specification.

[0044] The user I / F 63 is a touch panel that also functions as a display, and is located between the user operating the printer 1 and the controller 61, providing various information to the user and functioning as a user interface that accepts user operations. The user I / F 63 also allows the user to use the touch panel to select various options, buttons, icons, objects, etc. displayed on the liquid crystal display. However, the user interface that accepts user operations is not limited to a touch panel and may also be physical keys. In other words, a liquid crystal display and physical keys may be provided as a user interface.

[0045] In this embodiment, for convenience, the objects operated and selected by the user using printer 1 or the administrator managing printer 1 are referred to as "options," "buttons," "icons," "objects," etc., but they may be replaced with other words.

[0046] The network I / F 64 is a network I / F that connects the printer 1 to a network wirelessly or via a wired connection. For example, the printer 1 can receive a print instruction (including image data to be printed) sent from a terminal (such as a PC) connected to the same network via the network I / F 64, and execute printing in accordance with the received print instruction.

[0047] The solenoid 65 is an actuator included in the drive mechanism of the MP feed roller 51 and MP separation roller 52 described above, and is turned on by the controller 61 when conveyance of the sheets 3 stacked on the MP tray 41 begins. When the solenoid is turned on, the cam mechanism moves the MP feed roller 51 to a lowered position where it abuts against the upper surface of the sheets 3 positioned on the upper surface of the partition member 55, as described above, and further, the drive force from the conveyance motor 66 becomes transmittable to the MP feed roller 51 and MP separation roller 52, and feeding of the sheets 3 on the MP tray 41 begins. In other words, the solenoid 65 serves as a trigger for starting conveyance of the sheets 3.

[0048] Furthermore, the conveying motor 66 is a motor that serves as a drive source for the MP feed roller 51 and MP separation roller 52. Furthermore, although not shown, motors that serve as drive sources for other rollers such as the registration roller 15, separation roller 9, and feed roller 11 are also connected to the controller 61 in the same manner. However, instead of having a drive source for each roller, it is also possible to use a mechanism in which a single motor drives multiple rollers via an electromagnetic clutch or the like, with the controller 61 controlling the ON / OFF timing of the electromagnetic clutch. Note that the controller 61 can control each motor (rotation direction and torque) by controlling the current flowing through the motor.

[0049] The temperature sensor 68 is a sensor that detects the ambient temperature of the environment in which the printer 1 is installed. The first sensor 21 is a sensor that is located upstream of the registration rollers 15 in the sheet transport direction and detects the passage of the sheet 3 on the first transport path 14. Similarly, the second sensor 22 is a sensor that is located downstream of the registration rollers 15 in the sheet transport direction and detects the passage of the sheet 3 on the first transport path 14. The sheet presence sensor 47 is a sensor that detects the presence or absence of a sheet placed on the sheet placement surface 44a.

[0050] [Control processing by the controller] Next, among the various processes executed by the controller 61 of the printer 1 having the above configuration, cleaning control of the MP feed roller 51, which is executed when printing on a sheet 3 from the MP tray 41, will be described with reference to Figures 4 to 9. Figures 4 to 9 are flowcharts of the printing process of the printer 1. The printing process is executed after the printer 1 is turned on and when a print instruction (particularly a print instruction from the MP tray 41) is received from a terminal (such as a PC) connected to the same network via the network I / F 64. Note that each process shown in the flowcharts in Figures 4 to 9 below is stored in the memory 62 provided in the printer 1 and is executed by the controller 61.

[0051] First, in step (hereinafter abbreviated as S) 10, the controller 61 turns on the solenoid 65. As described above, the solenoid 65 is an actuator included in the drive mechanism of the MP feed roller 51 and the MP separation roller 52, and turning on the solenoid 65 positions the MP feed roller 51 in the lowered position. It is assumed that a sheet 3 is placed on the sheet placement surface 44a of the MP tray 41. Therefore, turning on the solenoid 65 positions the MP feed roller 51 in the lowered position, and the MP feed roller 51 comes into contact with the sheet 3 placed on the sheet placement surface 44a.

[0052] Then, in S12, the controller 61 starts driving the conveyance motor 66. As described above, by turning on the solenoid 65, the MP feed roller 51 is positioned in the lowered position, and the driving force of the conveyance motor 66 is ready to be transmitted to the MP feed roller 51 and the MP separation roller 52. Therefore, when the conveyance motor 66 starts to be driven, feeding of the sheet 3 on the MP tray 41 begins. As a result, the sheet 3 on the MP tray 41 is conveyed towards the registration rollers 15 via the second conveyance path 54.

[0053] At this time, a media type detection subroutine is executed in S14. In the media type detection subroutine, in S100 of FIG. 6, the controller 61 determines whether the media type of the sheet 3 detected by the media type detection sensor 67 is cardboard. That is, it determines whether the capacitance sensor of the media type detection sensor 67, which is disposed upstream of the registration rollers 15 in the sheet conveying direction, detects that the thickness of the sheet 3 is equal to or greater than a predetermined thickness, and whether the size sensor detects that the size of the sheet 3 is not a postcard size. At this time, if the capacitance sensor detects that the thickness of the sheet 3 is equal to or greater than a predetermined thickness, and if the size sensor detects that the size of the sheet 3 is not a postcard size, the controller 61 determines that the media type of the sheet 3 is cardboard (S100: YES). Then, in S102, the controller 61 sets the media type to cardboard.

[0054] Furthermore, in S100, the controller 61 determines that the media type of the sheet 3 is not cardboard unless the capacitance sensor detects that the thickness of the sheet 3 is equal to or greater than a predetermined thickness and the size sensor detects that the size of the sheet 3 is not postcard size (S100: NO). Then, in S104, the controller 61 determines whether the media type of the sheet 3 detected by the media type detection sensor 67 is a postcard. That is, it determines whether the capacitance sensor of the media type detection sensor 67 detects that the thickness of the sheet 3 is equal to or greater than a predetermined thickness and the size sensor detects that the size of the sheet 3 is postcard size. At this time, if the capacitance sensor detects that the thickness of the sheet 3 is equal to or greater than a predetermined thickness and the size sensor detects that the size of the sheet 3 is postcard size, the controller 61 determines that the media type of the sheet 3 is a postcard (S104: YES). Then, in S106, the controller 61 sets the media type to postcard.

[0055] Furthermore, in S104, unless the capacitance sensor detects that the thickness of sheet 3 is equal to or greater than a predetermined thickness and the size sensor detects that the size of sheet 3 is postcard size, the controller 61 determines that the media type of sheet 3 is not a postcard (S104: NO). Then, in S108, the controller 61 sets the media type to plain paper. In this way, once the media type is set in any of S102, S106, or S108, the media type detection subroutine ends.

[0056] When the media type detection subroutine ends, in S16 of Fig. 4, the controller 61 determines whether the set media type is a postcard. If the set media type is a postcard (S16: YES), in S18 the controller 61 adds 40 to the paper feed count (an example of a value related to the number of times a sheet has been fed). The paper feed count is stored in the memory 62, and its initial value is 0.

[0057] If the set media type is not a postcard (S16: NO), the controller 61 determines in S22 whether the set media type is cardboard. If the set media type is cardboard (S22: YES), the controller 61 determines in S24 whether the value detected by the temperature sensor 68, i.e., the ambient temperature of the printer 1, is below 10°C. If the ambient temperature of the printer 1 is below 10°C (S24: YES), the controller 61 adds 50 to the paper feed count in S26.

[0058] Furthermore, if the media type set in S22 is not cardboard (S22: NO) and if the ambient temperature of the printer 1 is 10°C or higher in S24 (S24: NO), the controller 61 adds 1 to the paper feed count in S28. That is, if the media type is postcard, 40 is added to the paper feed count. Also, if the media type is cardboard and the ambient temperature of the printer 1 is below 10°C, 50 is added to the paper feed count. Also, if the media type is cardboard but the ambient temperature of the printer 1 is above 10°C, 1 is added to the paper feed count. The number of added paper feed counts is set to a large value at low temperatures because calcium carbonate is likely to adhere to the separation roller 52 at low temperatures, and the separation performance of the separation roller 52 is likely to deteriorate. Also, if the media type is neither postcard nor cardboard, i.e., if it is plain paper, 1 is added to the paper feed count.

[0059] In this way, when a predetermined value according to the media type and the environmental temperature is added to the paper feed count in any of S18, S26, and S28, the controller 61 determines in S30 whether the paper feed count exceeds 1000 (an example of a first predetermined value). In other words, the controller 61 determines whether the paper feed count, to which predetermined values ​​according to the media type and the environmental temperature have been cumulatively added, exceeds 1000. If the paper feed count does not exceed 1000 (S30: NO), the controller 61 sets the CLN count to 0 in S31.

[0060] If the paper feed count exceeds 1000 (S30: YES), the controller 61 determines in S34 whether the paper feed count exceeds 2000 (an example of a second predetermined value). If the paper feed count does not exceed 2000 (S34: NO), the controller 61 sets the CLN count to 1 in S36. If the paper feed count exceeds 2000 (S34: YES), the controller 61 sets the CLN count to 2 in S38.

[0061] In this way, when the CLN count is set to a predetermined value in any of S31, S36, and S38, the controller 61 determines in S32 whether or not a sheet 3 is present on the sheet placement surface 44a of the MP tray 41 based on the detection value of the sheet presence / absence sensor 47. If a sheet 3 is not present on the sheet placement surface 44a of the MP tray 41 (S32: NO), a cleaning control subroutine is executed in S34.

[0062] In the cleaning control subroutine, in S200 of FIG. 7, the controller 61 determines whether the CLN count is 1 or greater. If the CLN count is 1 or greater (S200: YES), in S202 the controller 61 rotates the conveyance motor 66 a predetermined number of times at a predetermined speed. That is, when there is no sheet 3 on the sheet placement surface 44a of the MP tray 41, the MP feed roller 51 is in contact with the high-friction member 58, and the conveyance motor 66 is driven at this time. Therefore, when the MP feed roller 51 rotates while in contact with the high-friction member 58, cleaning control of the MP feed roller 51 is performed, in which paper dust adhering to the MP feed roller 51 is removed by the high-friction member 58. That is, when there is no sheet 3 on the sheet placement surface 44a of the MP tray 41 and the CLN count is 1 or greater (the paper feed count exceeds 1,000), cleaning control of the MP feed roller 51 is performed. In this way, when the cleaning control of the MP paper feed roller 51 is executed, in S204 the controller 61 resets the paper feed counter to 0. Then, the cleaning control subroutine ends. Also, if the CLN count is not 1 or more (S200: NO), that is, if the CLN count is 0, the processes of S202 and S204 are skipped and the cleaning control subroutine ends.

[0063] 5, if a sheet 3 is present on the sheet placement surface 44a of the MP tray 41 (S32: YES), the controller 61 determines in S40 whether the CLN count is 2. If the CLN count is 2 (S40: YES), the forced cleaning control subroutine is executed in S42.

[0064] In the forced cleaning control subroutine, the controller 61 stops driving the conveyance motor 66 in S300 of Fig. 8. Then, in S302, the controller 61 displays a message on the user I / F 63 saying, "Roller cleaning will be performed. Please remove sheets from the MP tray." In S304, the controller 61 determines whether or not a sheet 3 is present on the sheet placement surface 44a of the MP tray 41 based on the detection value of the sheet presence / absence sensor 47. At this time, if a sheet 3 is present on the sheet placement surface 44a of the MP tray 41 (S304: YES), the processes of S302 and S304 are repeated. That is, the user confirms the message displayed on the user I / F 63, removes the sheet 3 from the MP tray, and the processes of S302 and S304 are repeated until there are no more sheets 3 on the sheet placement surface 44a of the MP tray 41.

[0065] Furthermore, if the user checks the message displayed on the user I / F 63 and removes the sheet 3 from the MP tray, and there is no sheet 3 on the sheet placement surface 44a of the MP tray 41 (S304: NO), the controller 61 displays a message "Please press the start key" on the user I / F 63 in S306. Then, in S308, the controller 61 determines whether the start key has been pressed. At this time, if the start key has not been pressed (S308: NO), the processes of S306 and S308 are repeated. That is, the processes of S306 and S308 are repeated until the start key is operated.

[0066] Furthermore, if the start key is pressed (S308: YES), a cleaning control subroutine is executed in S310. In the cleaning control subroutine, cleaning control of the MP paper feed roller 51 is executed as described above, and the paper feed count is reset to 0. That is, if sheets 3 are continuously present on the sheet placement surface 44a of the MP tray 41 (S32: YES), that is, if sheets 3 are not removed from the sheet placement surface 44a, and the CLN count is 2 (S40: YES), that is, if the paper feed counter exceeds 2000, the user is prompted to remove the sheets 3 from the MP tray, and cleaning control of the MP paper feed roller 51 is forcibly executed.

[0067] When cleaning control of the MP feed roller 51 is forcibly executed in this way, the cleaning control subroutine ends, and in S314 of FIG. 9, the controller 61 displays a message on the user I / F 63 saying, "Roller cleaning is complete. Please set a sheet in the MP tray." Then, in S316, the controller 61 determines whether or not a sheet 3 is present on the sheet placement surface 44a of the MP tray 41 based on the detection value of the sheet presence / absence sensor 47. At this time, if a sheet 3 is not present on the sheet placement surface 44a of the MP tray 41 (S316: NO), the processes of S314 and S316 are repeated. In other words, the processes of S314 and S316 are repeated until the user confirms the message displayed on the user I / F 63 and sets a sheet 3 in the MP tray.

[0068] Furthermore, if the user checks the message displayed on the user I / F 63 and sets the sheet on the MP tray, and there is a sheet 3 on the sheet placement surface 44a of the MP tray 41 (S316: YES), the controller 61 displays a message "Please press the start key" on the user I / F 63 in S318. Then, in S320, the controller 61 determines whether the start key has been pressed. At this time, if the start key has not been pressed (S320: NO), the processes of S318 and S320 are repeated. That is, the processes of S318 and S320 are repeated until the start key is operated.

[0069] If the start key is pressed (S320: YES), then in S322 the controller 61 starts driving the carry motor 66. This ends the forced cleaning control subroutine.

[0070] 5, when the cleaning control subroutine in S34 is completed, when the forced cleaning control subroutine in S42 is completed, and when the CLN count is not 2 in S40 (S40: NO), that is, when the paper feed counter does not exceed 2000, the controller 61 determines in S36 whether or not there is print image data for the next page. That is, the controller 61 determines whether or not there is print image data for which printing processing should continue. If there is print image data for which printing processing should continue (S36: YES), the controller 61 starts driving the carry motor 66 in S12 and executes the processing from S14 onwards. If there is no print image data for which printing processing should continue (S36: NO), the controller 61 stops driving the carry motor 66 in S38, and the printing processing ends.

[0071] As described above in detail, the printer 1 according to this embodiment includes an MP tray 41 having a high-friction member 58 provided on the sheet placement surface 44a, a sheet presence / absence sensor 47 whose output changes depending on the presence or absence of a sheet 3 placed on the sheet placement surface 44a, an MP feed roller 51 that is provided on the sheet placement surface 44a at a position corresponding to the high-friction member 58 and that feeds the sheet 3 by rotating while in contact with the sheet 3 placed on the MP tray 41, a temperature sensor 68 whose output changes depending on the ambient temperature, a memory 62, and a controller 61. The controller 61 is capable of executing cleaning control to rotate the MP feed roller 51 while the MP feed roller 51 is in contact with the high-friction member 58 of the MP tray 41, and determines whether or not to execute cleaning control based on the output of the sheet presence / absence sensor 47, the output of the temperature sensor 68, and the value of the paper feed counter stored in the memory 62. This allows the printer 1 to maintain a stable sheet 3 supply capacity even when used in a variety of environments. Specifically, calcium carbonate is used as a pigment in sheets that require whiteness and smoothness, such as cardboard and high-quality paper. When a sheet containing calcium carbonate is fed by the MP feed roller 51 under low-temperature conditions, the calcium carbonate tends to adhere to the MP feed roller 51, which reduces the coefficient of friction of the MP feed roller 51. Therefore, when a sheet containing calcium carbonate is fed by the MP feed roller 51 under low-temperature conditions, the feeding capacity deteriorates more quickly than expected. In particular, because the MP tray 41 is structurally difficult to apply a strong feeding pressure to the MP feed roller 51 on the sheet 3, the reduced coefficient of friction of the MP feed roller 51 may significantly reduce the feeding capacity of the MP tray 41. In view of this, by determining whether or not to perform cleaning control based on the output of the sheet presence / absence sensor 47, the output of the temperature sensor 68, and the value of the paper feed counter stored in the memory 62, it becomes possible to perform cleaning control taking into account the environmental temperature of the printer 1. This makes it possible to change the frequency of cleaning control execution depending on the environmental temperature when, for example, a sheet containing calcium carbonate is fed from the MP tray 41, and to maintain a stable sheet 3 supply capacity in the printer 1 used in various environments.

[0072] Furthermore, each time a sheet 3 is fed from the MP tray 41, the controller 61 cumulatively adds an additional value that varies depending on the sheet type and an additional value corresponding to the output of the temperature sensor to a paper feed counter and stores the added values ​​in memory 62. Specifically, the controller 61 adds 40 to the paper feed counter each time a postcard is fed from the MP tray 41, and adds 1 to the paper feed counter each time a sheet of plain paper is fed from the MP tray 41. Furthermore, if the ambient temperature is below 10°C when a sheet of thick paper is fed from the MP tray 41, the controller 61 adds 50 to the paper feed counter, and if the ambient temperature is 10°C or higher when a sheet of thick paper is fed from the MP tray 41, the controller 61 adds 1 to the paper feed counter. Then, when the cumulatively added paper feed counter value exceeds 1000, the controller 61 determines that the execution condition for executing cleaning control is met. This makes it possible to change the frequency of cleaning control depending on the type of sheet, and also to change the frequency of cleaning control depending on the ambient temperature, thereby enabling the printer 1 used in a variety of environments to maintain a stable sheet 3 supply capacity.

[0073] Furthermore, the controller 61 executes cleaning control of the MP paper feed roller 51 when the output of the sheet presence / absence sensor 47 indicates that the sheet 3 is not present and the conditions for executing cleaning control are satisfied. This makes it possible to rotate the MP paper feed roller 51 while it is in contact with the high friction member 58, and makes it possible to preferably recover the friction coefficient of the MP paper feed roller 51.

[0074] Also, for example, when the drive of the conveyance motor 66 starts in S12 (see FIG. 4), the Xth sheet 3 is conveyed, and the cumulatively added sheet feed counter exceeds 1000 (S30: YES) (see FIG. 5), the execution condition for cleaning control is satisfied. Then, when the execution condition for cleaning control is satisfied and the output of the sheet presence / absence sensor 47 indicates that there is no sheet (S32: NO) (see FIG. 5), cleaning control is executed (S34) (see FIG. 5). Then, after the execution of cleaning control, when there is print image data for the next page (S36: YES) (see FIG. 5), the drive of the conveyance motor 66 starts in S12 (see FIG. 4), and the X+1th sheet 3 is conveyed. In other words, when the execution condition for cleaning control is satisfied during the conveyance of the Xth sheet 3, and the output of the sheet presence / absence sensor 47 indicates that there is no sheet, cleaning control is executed before the paper feed operation for the X+1th sheet 3 starts. Therefore, the controller 61 executes cleaning control before starting the next paper feeding operation (paper feeding operation for the X+1th sheet 3) following the paper feeding operation (paper feeding operation for the Xth sheet 3) when the output of the sheet presence / absence sensor 47 indicates that no sheet is present while the conditions for executing cleaning control are met. As a result, if there are no more sheets 3 on the MP tray 41 by the transport of the Xth sheet 3 and the conditions for executing cleaning control are satisfied, cleaning control can be executed without the user being aware of it before the feeding operation of the X+1th sheet 3 starts.

[0075] Furthermore, the controller 61 executes cleaning control by rotating the conveyance motor 66 a predetermined number of times in S202 (see FIG. 7), and then resets the paper feed counter to 0 in S204. This makes it possible to appropriately count the execution conditions for cleaning control that is executed after cleaning control has been executed.

[0076] Furthermore, after the paper feed count exceeds 1000 (S30: YES) (see FIG. 5), the controller 61 does not execute cleaning control, and if the paper feed count exceeds 2000 (S34: YES) (see FIG. 5), the controller 61 outputs information prompting execution of cleaning control in the forced cleaning control subroutine. Specifically, the controller 61 displays a message on the user I / F 63 saying "Roller cleaning will be performed. Please remove sheets from the MP tray" (S302) (see FIG. 8). Therefore, it is possible to prompt the user to execute cleaning control when a large number of sheets 3 are set on the MP tray 41 and the sheets 3 on the MP tray 41 do not run out. As a result, when the sheet feed count value is 2000, at which point it is estimated that the adhesion of calcium carbonate to the MP feed roller 51 will exceed its limit, it is possible to forcibly execute cleaning control before the adhesion of calcium carbonate to the MP feed roller 51 exceeds its limit. Also, by displaying a message on the user I / F 63, the user can remove the sheets 3 from the MP tray 41 without hesitation. The output of the information prompting the execution of cleaning control is not limited to display on the user I / F 63, and various output methods such as audio output, output by a lamp, etc. can be adopted.

[0077] In addition, the printer 1 is provided with a media type detection sensor 67 as an acquisition unit that acquires sheet information regarding the sheets to be fed, and the controller 61 determines the value to be added to the paper feed count based on the media type detected by the media type detection sensor 67. This makes it possible to add an appropriate value according to the type of sheet to the paper feed count. Note that the detection of the media type is not limited to the media type detection sensor 67, and can be performed using various sensors. For example, the length dimension of the sheet 3 in the conveying direction may be detected by the first sensor 21 and the second sensor 22, and the media type may be estimated based on the detected length dimension. Furthermore, sheet information regarding the sheets to be fed may be acquired without using a sensor. For example, when a user inputs a print command via the user I / F 63, the network I / F 64, or the like, sheet information such as the media type may be input. In such a case, the user I / F 63, the network I / F 64, or the like may function as an acquisition unit, and a value to be added to the paper feed count may be determined based on the sheet information input via the user I / F 63, the network I / F 64, or the like. In this way, when the value to be added to the paper feed count is determined based on the sheet information input via the user I / F 63, the network I / F 64, or the like, the media type detection subroutine of S14 in FIG. 4 is not executed, and the processes of S16 and S22 are executed based on the input sheet information.

[0078] The present invention is not limited to the above-described embodiment, and it goes without saying that various improvements and modifications are possible within the scope of the present invention. For example, in this embodiment, an example has been described in which the printing process shown in Figures 4 to 9 is performed particularly on a sheet 3 transported from an MP tray (multipurpose tray) 41, but the printing process shown in Figures 4 to 9 can also be performed on a sheet transported from a paper feed tray 8. In this case, the paper feed tray 8 corresponds to the sheet loading section, the paper feed roller 11 corresponds to the paper feed roller, and the paper pressure plate 16 corresponds to the sheet loading surface. Furthermore, the output changes depending on whether or not a sheet is placed on the paper pressure plate 16. A sheet presence / absence sensor is disposed on the paper pressure plate 16. Furthermore, a high-friction member is disposed on the portion of the paper pressure plate 16 that the paper feed roller 11 comes into contact with when no sheet is placed on the paper pressure plate 16.

[0079] In the above embodiment, the additional value is determined according to the ambient temperature and the sheet type. That is, if the sheet being fed is cardboard and the ambient temperature is less than 10°C, the additional value is determined to be 50. On the other hand, the additional value may be determined only according to the ambient temperature. For example, regardless of the type of sheet being fed, if the ambient temperature is less than 10°C, the additional value may be determined to be a predetermined value. That is, whether the sheet being fed is plain paper or a postcard, if the ambient temperature is less than 10°C, the additional value may be determined to be a predetermined value.

[0080] In the above embodiment, a sheet feed count that is incremented each time a sheet is fed is used as a value related to the number of times a sheet is fed, but various values ​​can be used. For example, a count that is incremented only when a specific type of sheet is fed may be used.

[0081] Furthermore, in the above embodiment, three types of sheets, namely postcards, cardboard, and plain paper, are used as the types of sheets, but any type of sheet can be used.

[0082] Furthermore, in the above embodiment, the printer 1 has been described as an example of the sheet conveying device, but it may also be, for example, a copy machine, a facsimile machine, or a multifunction machine having a printer function and a scanner function. [Explanation of symbols]

[0083] 4: Feeder section (sheet transport device), 41: MP tray (manual feed tray) (sheet placement section), 44a: Sheet placement surface, 47: Sheet presence / absence sensor, 51: MP paper feed roller (paper feed roller), 58: High friction member, 61: Controller (control section), 62: Memory, 63: User I / F (display section), 67: Media type detection sensor (acquisition section), 68: Temperature sensor

Claims

1. a sheet placement section having a high-friction member provided on a sheet placement surface; a sheet presence / absence sensor whose output changes depending on whether or not a sheet is placed on the sheet placement surface; a sheet feed roller provided at a position corresponding to the high-friction member of the sheet placement section, the sheet feed roller rotating in contact with the sheet placed on the sheet placement section to feed the sheet; A temperature sensor whose output changes depending on the ambient temperature; Memory and a control unit, The control unit a cleaning control can be executed to rotate the paper feed roller while the paper feed roller is in contact with the high friction member of the sheet placement unit; A sheet conveying device characterized in that it determines whether to perform the cleaning control based on the output of the sheet presence / absence sensor, the output of the temperature sensor, and a value related to the number of times the sheet has been fed stored in the memory.

2. The control unit The sheet conveying device according to claim 1, characterized in that as a value related to the number of times of paper feeding, a sheet type addition value which differs depending on the sheet type and a temperature addition value corresponding to the output of the temperature sensor are cumulatively added each time a sheet is fed and stored in the memory, and when the cumulatively added value related to the number of times of paper feeding exceeds a first predetermined value, it is determined that the execution condition for executing the cleaning control is met.

3. The control unit 3. The sheet transport device according to claim 2, wherein the cleaning control is executed when the output of the sheet presence / absence sensor indicates that a sheet is not present and the execution condition is satisfied.

4. The control unit 4. The sheet conveying device according to claim 3, wherein the cleaning control is executed before starting the next paper feeding operation when the output of the sheet presence / absence sensor indicates that a sheet is not present while the execution conditions are satisfied.

5. The control unit 5. The sheet transport device according to claim 2, wherein the value relating to the number of times of paper feeding is reset after the cleaning control is executed.

6. The control unit The sheet conveying device according to claim 2, characterized in that, after the execution conditions are met, if the value related to the number of paper feeds exceeds a second predetermined value greater than the first predetermined value without executing the cleaning control, information prompting the execution of the cleaning control is output.

7. the sheet conveying device further includes a display unit; The control unit The sheet conveying device according to claim 6 , wherein information prompting execution of the cleaning control is displayed on the display unit.

8. the sheet conveying device further includes an acquisition unit (user interface, communication interface, media type detection sensor) for acquiring sheet information related to the sheet to be fed; The control unit The sheet conveying apparatus according to claim 2 , wherein the sheet type additional value is determined based on the sheet information acquired by the acquisition unit.

9. the acquiring unit is a media type detection sensor that detects a media type of a sheet as the sheet information, The control unit 9. The sheet conveying apparatus according to claim 8, wherein the sheet type addition value is determined based on the media type detected by the media type detection sensor.

10. 2. The sheet transport device according to claim 1, wherein the sheet placement unit is a manual feed tray.

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