Sheet loading device and image forming apparatus

Abstract

To provide a sheet loading device that can separately control an automatic lifting operation section and a manual lifting operation section of a loading base, maintain convenience of a lifting operation of the loading base, and prevent destruction of the device.SOLUTION: This sheet loading device comprises: a tray provided with a lifting mechanism and on which a plurality of sheets can be loaded; a conveyance unit that is disposed above the tray and that conveys the sheets in a conveying direction; and a control unit that controls the height position of the tray on which the sheets conveyed by the conveyance unit are loaded via the lifting mechanism. The device further comprises, in a lifting space where the tray can be lifted, an upper limit detection sensor for detecting reaching of uppermost one of the sheets loaded on the tray to a lifting limit position, a lifting temporary stop sensor for detecting reaching of the uppermost one of the sheets loaded on the tray to a lifting temporary stop position lower than the lifting limit position, a lower limit detection sensor for detecting reaching of the tray to a lower limit position, and a lower temporary stop sensor for detecting reaching of the tray to a lower temporary stop position higher than the lower limit position.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a sheet stacking device and an image forming apparatus.

Background Art

[0002] There is known a sheet stacking device including a conveyance unit that conveys sheets and a stacking unit that has a stacking table (pallet) on which the conveyed sheets are stacked, and having a stacking method in which as the stacking amount of sheets on the pallet increases, the stacking table continues to descend so that a relatively large amount of sheets can be stacked at once. Also, there is known an image forming apparatus including an image forming unit that forms an image on the sheets conveyed by the conveyance unit and a sheet stacking device that stacks the sheets on which the image has been formed by the image forming unit.

[0003] When the sheet on which the image has been formed is discharged (during printing), the sheet stacking device needs to raise the pallet to receive the sheet at an upper position and lower the pallet as the sheet is discharged so that the uppermost position of the sheet stacking surface does not reach the height limit. There are already known methods in which the raising and lowering operation of this pallet is automatically performed after the operator presses a button, and a method in which the pallet is raised and lowered only while the operator is pressing the button.

[0004] The sheet stacking device is installed on the downstream side of the image forming unit. When the pallet is automatically controlled to move up and down in the sheet stacking device, the pallet may collide with the configuration (paper discharge unit) that discharges the sheet from the image forming unit, damaging a part of the image forming apparatus or a part of the sheet stacking device.

[0005] Disclosed is an anti - overshoot device for a paper stacking device that mainly aims to prevent damage to components as described above, includes an upper limit detector, and has a function of detecting that the pallet has risen up to before the upper limit detector and decelerating the rising speed of the paper stacking table (for example, see Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the technology disclosed in Patent Document 1, it is difficult to accurately detect the installation state of the pallet or the state of the load on the loading platform (such as unevenness of the sheets). Therefore, when the operator of the device is not present near the device, it is difficult to prevent collisions between the pallet and other components (parts) when the automatic lifting operation is performed. In other words, the conventional technology has challenges in achieving both the convenience of lifting and lowering the pallet and the prevention of damage to the device's parts in a sheet loading device.

[0007] The present invention aims to provide a sheet loading device that allows for the control of both an automatically operated lifting and lowering section of the loading platform and a manually operated lifting and lowering section by an operator, thereby maintaining operator convenience during the lifting and lowering of the loading platform and preventing damage to the device. [Means for solving the problem]

[0008] To solve the above technical problems, one aspect of the present invention relates to a sheet loading device, comprising: a tray equipped with a lifting mechanism capable of loading a plurality of sheets; a transport unit positioned above the tray and transporting the sheets in the transport direction; and a control unit that controls the height position of the tray on which the sheets transported by the transport unit are loaded via the lifting mechanism. A lifting operation unit that instructs the control unit to raise or lower the tray, Equipped with, In the lifting space from which the aforementioned tray can be raised and lowered, The tray comprises an upper limit detection sensor for detecting when the topmost sheet on the tray reaches an upper limit position, an upper pause sensor for detecting when the topmost sheet on the tray reaches an upper pause position which is lower than the upper limit position, a lower limit detection sensor for detecting when the tray reaches a lower limit position, and a lower pause sensor for detecting when the tray reaches a lower pause position which is higher than the lower limit position. The lifting and lowering operation unit notifies the control unit of an operation instruction in response to a predetermined operation, and the operation instruction includes an upward instruction to raise the tray, a downward instruction to lower the tray, and a stop instruction to stop the raising and lowering of the tray. , After the control unit has received notification of the upward or downward instruction based on a single operation of the lifting / lowering unit, it continues to raise or lower the tray even without further notification of the operation instruction. When the upward pause sensor or the downward pause sensor detects that the tray has reached the upward pause position or the downward pause position, it stops raising or lowering the tray. After the stop, it raises or lowers the tray only while the upward or downward instruction is being notified from the lifting / lowering unit. It is characterized by the following: [Effects of the Invention]

[0009] According to the present invention, it is possible to distinguish and control the automatic lifting and lowering operation section of the loading platform from the manual lifting and lowering operation section by the operator, thereby maintaining the convenience of the operator during the lifting and lowering operation of the loading platform and preventing damage to the device. [Brief explanation of the drawing]

[0010] [Figure 1] A schematic diagram showing the internal structure of an image forming apparatus. [Figure 2] A diagram showing the sheet loading device when the guide member is in the storage position. [Figure 3] A diagram showing the sheet loading device when the guide member is in the detachment position. [Figure 4] A schematic diagram of the lifting mechanism that raises and lowers the paper output tray. [Figure 5] A front view of the sheet loading unit according to this embodiment, which is equipped with the above-described lifting mechanism. [Figure 6] Internal configuration diagram of the sheet loading unit shown above. [Figure 7] This figure shows the hardware configuration of the image forming apparatus, including the sheet stacking unit described above. [Figure 8] A flowchart of the lifting control process in the sheet loading unit described above. [Figure 9] A flowchart of the lowering control process in the sheet loading unit described above. [Modes for carrying out the invention]

[0011] The embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a schematic diagram showing an example of the overall configuration and internal structure of a printer 1 as an embodiment of the image forming apparatus according to the present invention.

[0012] [Overall configuration of Printer 1, etc.] As shown in Figure 1, the printer 1 is a device that forms and discharges an image on a sheet M, which is a sheet-shaped medium, and comprises an image forming unit 2 and a sheet loading unit 3. Here, the sheet loading unit 3 corresponds to an embodiment of the sheet loading device according to the present invention. Details of the sheet loading unit 3 will be described later.

[0013] In this description, we assume that the medium to be transported and loaded is a sheet-like medium called a sheet M. Sheet M can be of various types. For example, paper, OHP sheets, thread, fibers, fabrics, leather, metal, plastic, etc., are possible, and are not limited to those listed above. Sheet M is a sheet-like medium on which an image can be formed, is a transportable medium, and is loadable, and of course, other materials besides those listed above are included. In the following description, we assume that sheet M is paper.

[0014] [Configuration of Image Forming Unit 2] The image forming unit 2 shown in Figure 1 mainly comprises a paper feed tray 10, a transport unit 20, and an image forming unit 30. The sheet loading unit 3 mainly comprises a front guide unit 40 and a paper output tray 50 (tray).

[0015] The paper feed tray 10 accommodates sheets M stacked together before an image is formed. The transport unit 20 transports the sheets M contained in the paper feed tray 10 to the output tray 50, passing through a position facing the image forming unit 30. The transport unit 20 includes a paper feed roller 21 and a plurality of roller pairs 22, 23, 24, 25, 26, and 27.

[0016] The paper feed roller 21 contacts and rotates against the topmost sheet M loaded on the paper feed tray 10. In response to the rotation of the paper feed roller 21, the sheet M is supplied to the conveyance path. A plurality of roller pairs 22 to 27 are arranged along the conveyance path. In FIG. 1, the conveyance path is indicated by a broken line. The plurality of roller pairs 22 to 27 are arranged at a predetermined interval. Then, the roller pairs 22 to 27 convey the sheet M by sandwiching and rotating the sheet M. The conveyance path shown in FIG. 1 is formed in a space that extends from the paper feed tray 10 through a position facing the image forming unit 30 to the paper discharge tray 50.

[0017] The conveyance directions of the sheet M by the roller pairs 22 to 27 are different from each other. Among the roller pairs 22 to 27, the conveyance direction of the sheet M by the roller pair 27 closest to the paper discharge tray 50 is the direction from the roller pair 26 to the roller pair 27 on the ground surface (which becomes a horizontal plane) where the printer 1 is installed. In this specification, when simply referred to as the "conveyance direction", it shall refer to the conveyance direction by the roller pair 27.

[0018] The image forming unit 30 according to the present embodiment employs an inkjet method of forming an image on the sheet M by discharging ink onto the sheet M. The image forming unit 30 includes a plurality of head modules that discharge inks of cyan, magenta, yellow, and black colors. Then, by discharging ink from each head module at a predetermined timing, an image is formed on the sheet M facing the image forming unit 30. However, the image forming unit 30 may be an electrophotographic method of forming an image by fixing toner on the sheet M.

[0019] [Sheet Loading Unit 3] The sheet loading unit 3 of the components of the printer 1 shown in FIG. 1 includes the roller pair 27 (conveying unit), the leading end guide 40, and the paper discharge tray 50. The sheet loading unit 3 constitutes an example of a sheet loading device that loads a plurality of sheets M.

[0020] The tip guide section 40 is positioned downstream of the roller pair 27 in the transport direction. The roller pair 27 and the tip guide section 40 are positioned above the paper output tray 50. The tip guide section 40 guides the leading edge of the sheet M being transported by the roller pair 27 downstream in the transport direction, thereby preventing the leading edge of the sheet M from lifting up as it freely falls toward the paper output tray 50.

[0021] [Example of operation of sheet loading unit 3] Figure 2 shows the sheet loading device when the sheet M, which has been transported from the image forming unit 2, is positioned in the position where the first guide member 44 accommodates it (accommodation position). Figure 3 shows the sheet loading device when the sheet M is positioned in the position where the first guide member 44 detaches it (detachment position). As shown in Figures 2 and 3, the front guide section 40 is composed of a guide drive roller 41, a guide driven roller 42, an endless annular belt 43, and a plurality of first guide members 44 and second guide members 45.

[0022] The guide drive roller 41 and the guide driven roller 42 are each rotatably supported on the housing of the sheet loading unit 3 at positions spaced apart in the conveying direction. The endless annular belt 43 is stretched between the guide drive roller 41 and the guide driven roller 42. When the driving force of the motor is transmitted and the guide drive roller 41 rotates, the endless annular belt 43 rotates between the guide drive roller 41 and the guide driven roller 42. The endless annular belt 43 rotates clockwise as shown in Figures 2 and 3. In other words, the endless annular belt 43 rotates in a direction in which its lower surface moves in the conveying direction and its upper surface moves in the opposite direction to the conveying direction.

[0023] The first guide member 44 and the second guide member 45 are attached at equal intervals to the outer surface of the endless annular belt 43. Therefore, as the endless annular belt 43 rotates, the first guide member 44 and the second guide member 45 move in the conveying direction on the underside of the endless annular belt 43 and move in the opposite direction to the conveying direction on the upper side of the endless annular belt 43. Note that the number of first guide members 44 and second guide members 45 is not limited to two.

[0024] The first guide member 44 has an internal space that accommodates a portion of the leading edge (the downstream end in the conveying direction) of the sheet M. More specifically, the first guide member 44 is composed of a first opening 44a, a first intermediate section 44b, and a first inner section 44c. The second guide member 45 is composed of a second opening 45a, a second intermediate section 45b, and a second inner section 45c, similar to the first guide member 44. The structure of the first guide member 44 will be described below.

[0025] The first opening 44a opens on the upstream side in the conveying direction (i.e., the side facing the roller pair 27) when the first guide member 44 is positioned on the lower side of the endless annular belt 43. The first intermediate portion 44b is located downstream of the first opening 44a in the conveying direction when the first guide member 44 is positioned on the lower side of the endless annular belt 43. The first intermediate portion 44b is also the portion in which the vertical gap is smaller than that of the first opening 44a and the first inner portion 44c. The first inner portion 44c is located downstream of the first intermediate portion 44b in the conveying direction when the first guide member 44 is positioned on the lower side of the endless annular belt 43. The first inner portion 44c is also the portion in which the leading edge of the sheet M that has entered the interior of the first guide member 44 through the first opening 44a comes into contact.

[0026] The vertical gaps of the first opening 44a, the first intermediate section 44b, and the first inner section 44c are set to be larger than the thickness of the sheet M that can be conveyed by the roller pair 27. That is, the first guide member 44 supports the sheet M without clamping it between its upper and lower walls, and without hindering the sheet M's movement. This prevents the sheet M from being damaged as it moves forward and backward relative to the first guide member 44. However, the vertical gap of the first intermediate section 44b is not limited to being smaller than that of the first opening 44a and the first inner section 44c; the vertical gaps of the first opening 44a, the first intermediate section 44b, and the first inner section 44c may be the same. Also, the vertical gap of the first inner section 44c may be smaller than that of the first intermediate section 44b.

[0027] Furthermore, when the first guide member 44 is positioned on the lower side of the endless annular belt 43, the upper surface of the lower wall of the first opening 44a slopes upward toward the first intermediate portion 44b. Also, the surface of the first opening 44a that can contact the sheet M is a smooth surface without any protrusions or other imperfections. This reduces the resistance when the sheet M enters the internal space of the first guide member 44. Moreover, by constructing the portion of the first guide member 44 that can contact the sheet M from a highly smooth material such as metal or resin, the sheet M can enter even more smoothly.

[0028] The first guide member 44 is stopped in the storage position shown in Figure 2. The storage position is the position on the lower side of the endless annular belt 43 where the first opening 44a faces the roller pair 27. In other words, the storage position is a position in which the leading edge of the sheet M that has passed the roller pair 27 can be accommodated. That is, the leading edge of the sheet M conveyed by the roller pair 27 enters the internal space of the first guide member 44 through the first opening 44a and reaches the first inner part 44c.

[0029] When the leading edge of the sheet M enters the internal space of the first guide member 44, the endless annular belt 43 begins to rotate and stops again when the second guide member 45 reaches its storage position. At this time, the speed (maximum speed) of the first guide member 44 moving downstream in the conveying direction is set to be faster than the conveying speed of the sheet M by the roller pair 27. Therefore, the leading edge of the sheet M stored in the first guide member 44 detaches from the first guide member 44 at the detachment position shown in Figure 3, due to the speed difference between the conveying speed of the sheet M by the roller pair 27 and the moving speed of the second guide member 45.

[0030] The detachment position is on the underside of the endless annular belt 43, downstream in the conveying direction from the storage position. When the leading edge of the sheet M detaches from the first guide member 44, the rear end of the sheet M (the upstream end in the conveying direction) is still held by the roller pair 27. In other words, the leading edge guide 40 detaches the leading edge of the sheet M before the rear end of the sheet M passes the roller pair 27. To put it another way, the leading edge of the sheet M detaches from the leading edge guide 40, and then the rear end passes the roller pair 27.

[0031] As a result, the sheet M free-falls toward the paper output tray 50. More specifically, the leading edge of the sheet M begins free-falling at the release position, and then the trailing edge, which has passed through the roller pair 27, begins free-falling. That is, the leading edge guide section 40 plays the role of guiding the sheet M, which is being transported by the roller pair 27, toward the paper output tray 50 by accommodating the leading edge of the sheet M in the first guide member 44 and the second guide member 45 at the accommodating position, and releasing it from the first guide member 44 and the second guide member 45 at the release position. By intermittently rotating the endless annular belt 43, multiple sheets M can be discharged toward the paper output tray 50.

[0032] The endless annular belt 43 may start rotating when the leading edge of the sheet M contacts the first inner portion 44c of the first guide member 44, or it may start rotating just before the leading edge of the sheet M contacts the first inner portion 44c of the first guide member 44. By preventing the sheet M from contacting the first inner portion 44c, it is possible to prevent the leading edge of the sheet M from breaking. The position of the leading edge of the sheet M being conveyed by the roller pair 27 can be determined by a well-known position sensor (e.g., an optical sensor, a rotary encoder, or a combination thereof).

[0033] The output tray 50 accommodates multiple sheets M in a stacked state after images have been formed by the image forming unit 30. The output tray 50 is located downstream of the roller pair 27 in the transport direction, and below the roller pair 27 and the tip guide section 40. In other words, the output tray 50 is located where the sheets M, which have been transported by the roller pair 27 and whose tips have been guided by the tip guide section 40, fall to.

[0034] [Outline of the lifting mechanism 51] Here, the general outline of the lifting mechanism of the sheet loading unit 3 will be explained using Figure 4. As shown in Figure 4, the output tray 50, which serves as a loading platform, is configured to be able to move up and down in the vertical direction by the lifting mechanism 51. The lifting mechanism 51 mainly comprises a pair of pulleys 52a and 52b, a pair of chains 53a and 53b, a pair of weights 54a and 54b, an upper limit detection sensor 55, and a lower limit detection sensor 56. However, the specific structure of the lifting mechanism 51 is not limited to the example in Figure 4.

[0035] A pair of pulleys 52a and 52b are rotatably supported on the housing of the printer 1 above the output tray 50 and spaced apart from each other in the transport direction. A pair of chains 53a and 53b are stretched over the corresponding pulleys 52a and 52b. One end of each chain 53a and 53b is connected to the output tray 50, and the other end is connected to the corresponding weights 54a and 54b.

[0036] When pulleys 52a and 52b rotate in the first direction (in Figure 4, pulley 52a rotates clockwise and pulley 52b rotates counterclockwise), the paper output tray 50 rises and weights 54a and 54b descend. On the other hand, when pulleys 52a and 52b rotate in the second direction opposite to the first direction (in Figure 4, pulley 52a rotates counterclockwise and pulley 52b rotates clockwise), the paper output tray 50 descends and weights 54a and 54b rise.

[0037] The upper limit detection sensor 55 is a sensor that detects whether the position of the top sheet M loaded in the output tray 50 has reached the upper limit position, which is the limit position to which the lifting mechanism 51 is allowed to rise. The upper limit detection sensor 55 is located above the output tray 50. The upper limit detection sensor 55 is, for example, a reflective optical sensor comprising a light-emitting unit that emits light and a light-receiving unit that receives the light emitted from the light-emitting unit and reflected by the sheet M.

[0038] The upper limit detection sensor 55 outputs a detection signal to the controller 100 (see Figure 7), which will be described later, when a sheet M is present in the optical path, that is, when the top sheet M loaded in the output tray 50 reaches the upper limit position. On the other hand, the upper limit detection sensor 55 stops outputting the detection signal when no sheet M is present in the optical path. However, the upper limit detection sensor 55 is not limited to a reflective optical sensor, but may also be a transmissive optical sensor. When the controller 100 receives a detection signal indicating that the upper limit position has been reached (when a sheet M is present in the optical path), it immediately stops raising the output tray 50, regardless of the button operation or operating mode described later.

[0039] The lower limit detection sensor 56 is a sensor that detects when the maximum amount of sheets M has been loaded into the output tray 50, and detects whether or not the output tray 50 has reached the lower limit position, which is the limit position at which its descent is permitted. The lower limit detection sensor 56 is positioned, for example, opposite the weight 54b when the output tray 50 is full. The lower limit detection sensor 56 is, for example, a reflective optical sensor comprising a light-emitting unit that emits light and a light-receiving unit that receives the light emitted from the light-emitting unit and reflected by the weight 54b.

[0040] The lower limit detection sensor 56 outputs a detection signal to the controller 100 when a weight 54b is present in the optical path (i.e., the paper output tray 50 is full and has reached the lower limit position). On the other hand, the lower limit detection sensor 56 stops outputting the detection signal when the weight 54b is not present in the optical path. However, the lower limit detection sensor 56 is not limited to a reflective optical sensor, but may also be a transmissive optical sensor. When the controller 100 receives a detection signal indicating that the lower limit position has been reached (when a sheet M is present in the optical path), it immediately stops the descent of the paper output tray 50, regardless of the button operation or operating mode described later.

[0041] [Embodiment of a sheet loading device] Next, a sheet loading unit 3 as an embodiment of the sheet loading device according to the present invention will be described in detail. Figure 5 shows a front view of the sheet loading unit 3 according to this embodiment, and Figure 6 shows a schematic diagram of the internal configuration.

[0042] The raising and lowering of the paper output tray 50, performed by the aforementioned lifting mechanism 51, is carried out by operating a number of control buttons located on the front wall of the housing of the sheet loading unit 3. The control buttons for the lifting operation include an upward button 62, a stop button 63, and a downward button 64, and these are provided in a position and arrangement that is easy for the operator to operate. For example, as illustrated in Figure 5, they are provided on the front wall of the sheet loading unit 3, near the lifting space of the paper output tray 50.

[0043] The lift button 62 is a button that the operator presses when they want to raise the output tray 50. When the lift button 62 is pressed, a lift command is sent to the controller 100, which will be described later. Upon receiving the lift command, the controller 100 rotates the pulleys 52a and 52b in the first direction to raise the output tray 50. In automatic lifting mode, when the sheet loading unit 3 is operating, once the button is pressed, the tray will continue to rise until the highest point of the sheet M reaches the installation position of the lift pause sensor 71, which will be described later, even if the operation is stopped.

[0044] The stop button 63 is a button that is operated (pressed) in automatic lifting mode when the operator wants to stop the raising or lowering of the output tray 50 after having already performed an raising or lowering operation. When the stop button 63 is operated, a stop command is sent to the controller 100, which will be described later, to cancel the previously performed operation command. Upon receiving the cancellation command, the controller 100 stops the rotation of the pulleys 52a and 52b.

[0045] The down button 64 is a button that the operator presses when they want to lower the paper output tray 50. When the down button 64 is pressed, a down command is sent to the controller 100, which will be described later. Upon receiving the down command, the controller 100 rotates the pulleys 52a and 52b in the second direction to lower the paper output tray 50. Note that when the sheet loading unit 3 is operating in automatic lifting mode, once the button is pressed, the paper output tray 50 will continue to lower even if the operation is stopped, until its height reaches the installation position of the down pause sensor 72, which will be described later.

[0046] Furthermore, the front wall of the sheet loading unit 3 is also provided with a lifting mode switching button 65, which serves as a mode selection control unit for the operator to switch between the multiple lifting control modes provided by the sheet loading unit 3.

[0047] The lifting mode switching button 65 is equipped with a light-emitting function to provide a light-emitting pattern corresponding to the selected control mode. For example, by equipping the button with an LED and lighting up the LED of the button corresponding to the selected lifting control mode, the selected mode can be easily seen by the operator. The lifting modes that can be selected are "manual lifting mode" as the first control mode and "automatic lifting mode" as the second control mode.

[0048] Furthermore, the sheet loading unit 3 is equipped with multiple intrusion detection sensors 61 (61a, 61b) to detect unauthorized entry (intruders) from the opening of the lifting space, which serves as an access path to the paper output tray 50 on which the sheets M are loaded. Each intrusion detection sensor 61 consists of a pair of light-emitting elements and a light-receiving element, and is installed so as to be able to detect the entire entrance to the loading space. The dashed arrows in Figure 5 schematically show the light from the light-emitting element of the intrusion detection sensor 61 toward the light-receiving element. When either of these lights is blocked and the light-receiving element is unable to receive light, unauthorized entry into the loading space is detected. The controller 100, described later, stops the operation of the paper output tray 50 when the intrusion detection sensor 61 detects an intruder.

[0049] Figure 6 is a front view of the internal structure of the sheet loading unit 3. As shown in Figure 6, an upper limit detection sensor 55 and a lower limit detection sensor 56 are positioned in the loading space of the sheet loading unit 3, in the space where the output tray 50, which serves as the loading platform, moves up and down. The upper limit detection sensor 55 is also equipped with an upward pause sensor 71 (71a, 71b) that detects the height of the sheet M before the highest height of the sheet M is detected, and temporarily stops the upward movement of the output tray 50. Furthermore, the lower limit detection sensor 56 is equipped with a downward pause sensor 72 (72a, 72b) that detects the height of the output tray 50 before the highest height of the output tray 50 is detected, and temporarily stops the downward movement of the output tray 50.

[0050] The upward pause sensors 71 (71a, 71b) and the downward pause sensors 72 (72a, 72b) are both composed of a pair of light-emitting elements and a light-receiving element, similar to the intrusion detection sensor 61. Therefore, when the light emitted from the light-emitting elements of each sensor is blocked by the sheet M or the paper output tray 50, the output signal is changed to a state in which this can be notified. When the controller 100 acquires the output signal indicating that the light-receiving element cannot receive the light emitted from the light-emitting elements of the upward pause sensors 71 (71a, 71b) and the downward pause sensors 72, it temporarily stops the upward and downward movement of the paper output tray 50.

[0051] The installation position of the upward pause sensor 71 corresponds to the upward pause position, is lower than the installation position of the upper limit detection sensor 55 which is the upward limit position, and is installed at a position lower than the upper limit detection sensor 55 by an arbitrary amount A of upward movement.

[0052] Furthermore, the upward pause sensor 71 does not detect the height of the output tray 50, but rather the position of the topmost sheet M, which is stacked above the output tray 50, including the output tray 50. Therefore, the "upward pause position," which is the installation position of the upward pause sensor 71, means the limit point (limit position) at which the automatic upward movement of the output tray 50 is permitted, but it is not comparable to the position of the output tray 50 itself.

[0053] In other words, the "upward pause position" is a boundary that indicates the point where the upward movement of the output tray 50, on which the sheets M are loaded, must be temporarily stopped. This position is a distinct area that is treated as unsuitable for automatic upward movement because upward movement beyond this point increases the likelihood of the output tray 50, including the loaded sheets M, colliding with other parts. On the other hand, the range up to this "upward pause position" is considered to be a range where safe upward movement can be expected. Therefore, the section up to the upward pause position is pre-set as the "upward / downward intermediate section."

[0054] The installation position of the descent pause sensor 72 corresponds to the descent pause position, is higher than the installation position of the lower limit detection sensor 56 which is the descent limit position, and is installed at a position higher than the lower limit detection sensor 56 by an arbitrary amount B of possible descent.

[0055] Unlike the upward pause sensor 71, the downward pause sensor 72 detects the height of the output tray 50. This assumes that there are no components below the output tray 50 that could increase its thickness and potentially hinder its descent. In other words, the "downward pause position," where the downward pause sensor 72 is installed, represents the limit point (limit position) at which the automatic descent of the output tray 50 itself is permitted. To put it another way, the "downward pause position" indicates a boundary where the descent of the output tray 50 loaded with sheets M must be temporarily stopped. Descent below this position is considered a distinct area where collision with other components is highly likely, and automatic descent is unsuitable. On the other hand, the range up to this "downward pause position" is considered to be a range where safe descent can be expected. Therefore, the section up to the downward pause position is pre-set as the "upward / downward intermediate section."

[0056] Both the upward pause sensor 71 and the downward pause sensor 72 can be installed at any height position, and are held in a configuration that allows height adjustment, for example, by installing a bracket in an elongated hole having a longitudinal dimension in the height direction. Therefore, the arbitrary upward amount A corresponding to the upward monitoring section and the arbitrary downward amount B corresponding to the downward monitoring section can be set arbitrarily.

[0057] The paper output tray 50 is raised and lowered automatically or manually by operating the raise button 62 or the lower button 64 in the height space between the raise pause sensor 71 and the lower pause sensor 72, i.e., the intermediate raising and lowering section which is the automatic raising and lowering section. When the automatic raising and lowering mode is selected, for example, even if the raise button 62 is pressed and then released, the paper output tray 50 will automatically rise until it reaches its upper limit position. Similarly, even if the lower button 64 is pressed and then released, the paper output tray 50 will automatically lower until it reaches its lower limit position. If the stop button 63 is pressed while the paper output tray 50 is automatically raising and lowering in the intermediate raising and lowering section, the raising and lowering operation of the paper output tray 50 will stop.

[0058] On the other hand, when "manual lifting mode" is selected, for example, the unit will rise while the lift button 62 is pressed, and will automatically stop when released, even if the output tray 50 has not reached its upper limit position. Similarly, the unit will lower while the lower button 64 is pressed, and will automatically stop when released, even if the output tray 50 has not reached its lower limit position.

[0059] Furthermore, regardless of whether the lifting operation is performed in "automatic lifting mode" or "manual lifting mode," if either the lifting pause sensor 71 or the lowering pause sensor 72 detects that the paper output tray 50 has reached its limit position, the lifting operation of the paper output tray 50 will always be stopped.

[0060] When the upward pause sensor 71 detects and pauses, the system enters an operation standby state. After this operation standby state, if the operator wants to raise the output tray 50 further, even if the automatic lifting mode is selected, the output tray 50 will only rise while the operator continues to operate the upward button 62. Similarly, when the downward pause sensor 72 detects and pauses, the system enters an operation standby state. After this operation standby state, if the operator wants to lower the output tray 50 further, even if the automatic lifting mode is selected, the output tray 50 will only lower while the operator continues to operate the downward button 64.

[0061] With the above configuration, the lifting method can be changed in specific sections, and sections where automatic lifting may cause damage to parts are set by the arbitrary amount of upward movement A and the arbitrary amount of downward movement B. This makes it possible to distinguish and control sections where manual operation is desirable from the standpoint of preventing damage to the device, while maintaining the convenience of the operator in the lifting and lowering operation of the paper output tray 50.

[0062] [Example of control configuration] Next, the control configuration of the printer 1 according to this embodiment will be described with reference to Figure 7. Figure 7 is a diagram showing the hardware configuration of the printer 1. The printer 1 has a configuration in which a CPU (Central Processing Unit) 101 as a control means, a RAM (Random Access Memory) 102 as a storage means, a ROM (Read Only Memory) 103 as a storage means, an HDD (Hard Disk Drive) 104 as a storage means, and an I / F 105 as an interface are connected via a common bus 109 as a communication means. The CPU 101, RAM 102, ROM 103, and HDD 104 are examples of the controller 100.

[0063] The controller 100 controls the entire printer 1 by coordinating the operation of the image forming unit 2 and the sheet loading unit 3.

[0064] The CPU 101 is a computing device that executes calculations specified in a predetermined control program for controlling the overall operation of the printer 1. The RAM 102 is a volatile storage medium that allows for high-speed reading and writing of information and is used as a workspace for the CPU 101 when processing information. The ROM 103 is a read-only, non-volatile storage medium that stores programs such as firmware. The HDD 104 is a non-volatile storage medium that allows for reading and writing of information and has a large storage capacity, and stores the OS (Operating System), various control programs, application programs, etc.

[0065] Printer 1 processes control programs stored in ROM 103, information processing programs (application programs) loaded into RAM 102 from storage media such as HDD 104, etc., using the arithmetic functions of the CPU 101. This processing constitutes a software control unit that includes various functional modules of Printer 1. The combination of this software control unit and the hardware resources installed in Printer 1 constitutes functional blocks that realize the functions of Printer 1.

[0066] I / F105 is an interface that connects the transport unit 20, image forming unit 30, tip guide unit 40, lifting mechanism 51, and pause detection unit 70 to the common bus 109. In other words, the controller 100 controls the operation of the transport unit 20, image forming unit 30, tip guide unit 40, lifting mechanism 51, pause detection unit 70, and tray standby notification unit 80, which acts as a notification unit, through I / F105.

[0067] The pause detection unit 70 acquires the output signals from the upward pause sensors 71 (71a, 71b) and the downward pause sensors 72 (72a, 72b). Based on the changes in the output signals acquired by the pause detection unit 70, the controller 100 determines whether the paper output tray 50 has reached its upward limit position or whether it has reached its downward limit position. When the controller determines that the paper output tray 50 has reached its upward limit position or downward limit position, it stops the upward and downward movement of the paper output tray 50 regardless of the content of the operation input.

[0068] Furthermore, the pause detection unit 70 also acquires the output signals from multiple intrusion detection sensors 61. The controller 100 also stops the raising and lowering operation of the paper output tray 50 when it detects unauthorized intrusion into the loading space based on the output signals from the intrusion detection sensors 61.

[0069] [Lifting and lowering control processing] Next, the flow of the lifting and lowering control process performed in the sheet loading unit 3 according to this embodiment will be explained using a flowchart. Figure 8 illustrates the flow of the process when controlling the output tray 50 to rise. Figure 9 illustrates the flow of the process when controlling the output tray 50 to lower. The lifting and lowering operations described below illustrate the case when the lifting and lowering mode is the automatic lifting and lowering mode.

[0070] [Increase control processing] When raising the output tray 50, the operator first presses the raise button 62. Therefore, when the controller 100 detects that the raise button 62 has been pressed, it starts raising the output tray 50 (S801). After the output tray 50 has started to rise, if the controller 100 detects that the stop button 63 has been pressed (S802:Yes), it stops raising the output tray 50 (S809). If the stop button 63 has not been pressed (S802:No), the controller 100 continues raising the output tray 50 until the rise pause sensor 71 detects the top of the sheet M (S803:No).

[0071] When the controller 100 detects that the lift-pause sensor 71 has reached the top of the sheet M (S803: Yes), it means that the output tray 50 has reached the upper limit of the intermediate lift-down section, so the controller 100 temporarily pauses the lifting of the output tray 50 (S804). The controller 100 then continues to keep the output tray 50 stopped until it detects that the lift button 62 has been pressed again (S805: No). When the output tray 50 temporarily pauses in S804, the controller 100 selectively controls one or more of the following to perform a predetermined notification action: emit a predetermined sound via the tray standby notification unit 80, flash the lift button 62, or do both. This allows the controller 100 to provide notification to the operator to prompt further operation.

[0072] When the controller 100 detects that the lift button 62 has been pressed again (S805: Yes), it resumes raising the output tray 50 (S806). The controller 100 then continues raising the output tray 50 until the lift button 62 is released, that is, while the lift button 62 is still being pressed (S807: No), and until the upper limit detection sensor 55 detects the top of the sheet M (S808: No).

[0073] The controller 100 pauses the raising of the paper output tray 50 (S804) when the paper output tray 50 resumes raising after the paper output button 62 is pressed again (S805:Yes), and when the paper output tray 50 is released (S806), and when the paper output button 62 is released (S807:Yes). In this case, the pause continues until the paper output tray 50 is pressed again (S805:No).

[0074] In other words, when the paper output tray 50 reaches the upward monitoring section, it always pauses, and subsequent upward movement only occurs when the operator operates (presses) the upward button 62. Therefore, in automatic lifting mode, the operator only needs to operate (press) the upward button 62 once, and does not need to operate the upward button 62 again for upward movement in the intermediate lifting sections. On the other hand, upward movement in the upward monitoring section only occurs while the upward button 62 is pressed, and the paper output tray 50 stops rising when the stop button 63 is operated (pressed) or when the upward button 62 is released.

[0075] With the above control, by operating the lift button 62 once, the output tray 50 can be automatically raised in the intermediate lifting section, and when it reaches the lifting monitoring section, the lifting will always be stopped, and it will only be allowed to rise when operated by the operator. In this way, while maintaining the convenience of the operator during the raising operation of the output tray 50, it is possible to distinguish and control sections where manual operation is desirable from the standpoint of preventing damage to the device.

[0076] [Downward control processing] When lowering the paper output tray 50, the operator first presses the down button 64. Therefore, the paper output tray 50 starts to lower when it is detected that the down button 64 has been pressed (S901). After lowering has started, if the stop button 63 is pressed (S902:Yes), the paper output tray 50 stops lowering (S909). If the stop button 63 is not pressed (S902:No), the paper output tray 50 continues to lower until the lowering pause sensor 72 detects that the paper output tray 50 is at its lowest point (S903:No).

[0077] When the controller 100 detects that the paper output tray 50 has reached its lowest point (S903: Yes) via the lowering pause sensor 72, the controller 100 pauses the lowering of the paper output tray 50 because it has reached the lower limit of the intermediate lifting section (S904). The controller 100 then keeps the paper output tray 50 stopped until it detects that the lowering button 64 is pressed (S905: No). When the paper output tray 50 pauses in S904, the controller 100 selectively controls one or more of the following actions via the tray standby notification unit 80: emit a predetermined sound, flash the lowering button 64, or do both, to perform a predetermined notification action. This allows the controller 100 to provide notification to the operator to prompt them to perform the next operation.

[0078] When the controller 100 detects that the down button 64 has been pressed (S905: Yes), it resumes the descent of the paper output tray 50 (S906). The controller 100 then continues to descent the paper output tray 50 until the down button 64 is released (S906: No) and until the lower limit detection sensor 56 detects that the paper output tray 50 is at its lowest point (S907: No).

[0079] The controller 100 pauses the descent of the paper output tray 50 (S904) when the down button 64 is pressed again (S905:Yes), the paper output tray 50 resumes its descent (S906), and the down button 64 is released (S907:Yes). In this case, the pause continues until the down button 64 is pressed again (S905:No).

[0080] In other words, when the paper output tray 50 reaches the lowering monitoring section, it always pauses, and subsequent lowering only occurs when the operator is operating (pressing) the lowering button 64. Therefore, in automatic lifting mode, the operator does not need to operate (press) the lowering button 64. On the other hand, the lowering operation in the lowering monitoring section only occurs while the lowering button 64 is pressed, and the paper output tray 50 stops descending when the stop button 63 is operated (pressed) or when the lowering button 64 is released.

[0081] With the above control, the paper output tray 50 can be lowered automatically by operating the lowering button 64 once, and when it approaches the lower limit, it stops temporarily so that it can be lowered by the operator. In this way, while maintaining the convenience of the operator during the lowering operation of the paper output tray 50, it is possible to distinguish and control the section in which manual operation is desirable from the standpoint of preventing damage to the device.

[0082] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the technical essence, and all technical matters included in the technical concept described in the claims are subject to the present invention. The above embodiments are shown as preferred examples, but those skilled in the art can realize various modifications from the disclosed content. Such modifications are also included in the technical scope described in the claims. [Explanation of symbols]

[0083] 1: Printer 2: Image forming unit 3: Sheet loading unit 30: Image forming unit 40:Tip guide part 50: Paper output tray 51: Lifting mechanism 55: Upper limit detection sensor 56: Lower limit detection sensor 61: Intrusion detection sensor 62: Up button 63: Stop button 64: Down button 65: Height adjustment mode switching button 70: Pause detection unit 71: Ascending pause sensor 72: Descending pause sensor 80: Tray Standby Notification Unit 100: Controller [Prior art documents] [Patent Documents]

[0084] [Patent Document 1] Japanese Utility Model Publication No. 06-006334

Claims

1. Equipped with a lifting mechanism, it has a tray that can hold multiple sheets, A conveying unit positioned above the aforementioned tray and transporting the sheet in the transport direction, A control unit controls the height position of the tray on which the sheets transported by the transport unit are loaded, via the lifting mechanism, The system includes a lifting operation unit that instructs the control unit to raise or lower the tray, In the lifting space from which the aforementioned tray can be raised and lowered, An upper limit detection sensor for detecting when the topmost sheet stacked on the tray reaches its upper limit position, A lift pause sensor for detecting when the topmost seat on the tray reaches a lift pause position, which is a position lower than the lift limit position, A lower limit detection sensor for detecting when the tray has reached its lower limit position, The system includes a descending pause sensor for detecting when the tray reaches a descending pause position which is higher than the aforementioned descending limit position, The lifting operation unit notifies the control unit of an operation instruction in accordance with a predetermined operation. The aforementioned operation instructions include an upward instruction to raise the tray, a downward instruction to lower the tray, and a stop instruction to stop the raising and lowering of the tray. After the control unit has received notification of the raising or lowering instruction based on a single operation of the lifting / lowering operation unit, it will continue to raise or lower the tray even if it does not receive further notification of the operation instruction. When the upward pause sensor or the downward pause sensor detects that the tray has reached the upward pause position or the downward pause position, the upward or downward movement of the tray is stopped. After the stop, the tray will be raised or lowered only while the upward or downward instruction is received from the lifting / lowering control unit. A sheet loading device characterized by the following features.

2. The lifting operation unit is, The system includes a mode selection operation unit that notifies the control unit of the operation instruction, enabling the selection of a first control mode in which the tray continues to rise or fall in accordance with the operation instruction while the upward or downward instruction is notified, and stops if the operation instruction is notified; and a second control mode in which, after the upward or downward instruction has been notified once based on a single operation of the lifting / lowering operation unit, the tray continues to rise or fall even if the operation instruction is notified, and stops the raising or lowering of the tray when the upward pause sensor or the downward pause sensor detects that the tray has reached the upward pause position or the downward pause position. The sheet loading device according to claim 1.

3. A tray equipped with a lifting mechanism and capable of loading multiple sheets, A conveying unit positioned above the aforementioned tray and transporting the sheet in the transport direction, A control unit controls the height position of the tray on which the sheets transported by the transport unit are loaded, via the lifting mechanism, The system includes a lifting operation unit that instructs the control unit to raise or lower the tray, In the lifting space from which the aforementioned tray can be raised and lowered, An upper limit detection sensor for detecting when the topmost sheet stacked on the tray reaches its upper limit position, A lift pause sensor for detecting when the topmost seat on the tray reaches a lift pause position, which is a position lower than the lift limit position, A lower limit detection sensor for detecting when the tray has reached its lower limit position, The system includes a descending pause sensor for detecting when the tray reaches a descending pause position which is higher than the aforementioned descending limit position, The lifting operation unit notifies the control unit of an operation instruction in accordance with a predetermined operation. The aforementioned operation instructions include an upward instruction to raise the tray, a downward instruction to lower the tray, and a stop instruction to stop the raising and lowering of the tray. The control unit raises or lowers the tray in response to the operation instruction. The aforementioned lifting and lowering operation unit is The system includes a mode selection operation unit that notifies the control unit of the operation instruction to enable the selection of a first control mode, in which the tray continues to rise or fall in accordance with the operation instruction while the upward or downward instruction is notified, and stops if the operation instruction is notified; and a second control mode, in which, after the upward or downward instruction has been notified once based on a single operation of the lifting operation unit, the tray continues to rise or fall even if the operation instruction is notified, and stops the raising or lowering of the tray when the upward pause sensor or the downward pause sensor detects that the tray has reached the upward pause position or the downward pause position. In the second control mode, after the stop, the tray is raised or lowered only while an upward command or downward command is received from the lifting / lowering operation unit. A sheet loading device characterized by the following features.

4. The mode selection operation unit is equipped with a light emission function that produces a light emission pattern corresponding to the selected control mode. The sheet loading device according to claim 2 or 3.

5. The upward pause sensor and the downward pause sensor are held in an adjustable height position within the lifting space. A sheet loading device according to any one of claims 1 to 4.

6. The control unit continues to raise or lower the tray in accordance with the operation instruction while the operation instruction to raise or lower is notified, and stops the tray when no operation instruction is notified. A sheet loading device according to any one of claims 1 to 5.

7. The control unit stops the tray when it receives a stop command while it is continuing to raise or lower the tray in response to the operation command. A sheet loading device according to any one of claims 1 to 6.

8. The tray is equipped with a notification unit that notifies when it has entered an operation standby state. When the control unit detects that the tray has reached the upward pause position or the downward pause position using the upward pause sensor or the downward pause sensor, it notifies the control unit of this fact via the notification unit. A sheet loading device according to any one of claims 1 to 7.

9. After the tray has reached the upward pause position or the downward pause position, detected by the upward pause sensor or the downward pause sensor, The control unit raises or lowers the tray only while it is notified of the raising instruction or the lowering instruction from the lifting operation unit. A sheet loading device according to any one of claims 1 to 8.

10. An image forming unit that forms an image on a sheet, An image forming apparatus comprising a sheet stacking device according to any one of claims 1 to 9, which stacks sheets on which images have been formed by the image forming unit onto the tray.

Images