Field of the Invention
The present invention relates to a feeding apparatus and a printing apparatus, and more specifically to a feeding mechanism that separates and feeds sheets one by one using a separation surface.
Description of the Related Art
As a feeding mechanism that separates sheets using a separation surface, the feeding mechanism is known that uses two separation surfaces such as disclosed in Japanese Patent No. 3501714. The feeding mechanism that is disclosed in Japanese Patent No. 3501714 is such that the separation surface comprises a first separation surface, and a second separation surface that has a higher friction coefficient than the first separation surface, and is provided so as to be able to move along the first separation surface and in the direction of movement of a sheet that is output by a feed roller. By providing the second separation surface so as to be able to move, it becomes possible to feed sheets without deforming a sheet regardless of the stiffness of the sheet such as whether the sheet is thin or thick. Moreover, the second separation surface is able to prevent overlap feeding of sheets by an operation of returning to the upstream side by the elastic force of spring.
However, when applying the feeding mechanism disclosed in Japanese Patent No. 3501714 to a so-called auto-sheet feeder in which the sheet mounting surface of a sheet stacking device makes a comparatively large angle with respect to horizontal, and sheets are set so as to be inclined downward from the top, there are the following problems.
For example, when the elastic force of the spring that return the second separation surface to the upstream side is relatively weak, the second separation surface may move toward the downstream side due to the weight of plural sheets that are set on the sheet-mounting surface and due to the stiffness of the sheets. When the top sheet is separated and fed in such conditions, the front-end section of sheets other than the top sheet may become deformed along the separation surface due to the movement of the second separation surface, and the balance between the elastic force of the springs and the force acted by the sheets may be lost, resulting in only the second separation surface returning to the upstream side. As a result, the front ends of the sheets may drop further toward the downstream side than the second separation surface, the breaking force created by the high friction coefficient of the second separation surface may be lost and overlap feeding of sheets may occur. In contrast, when the elastic force of the spring is relatively large, for example, the second separation surface becomes unable to move and then may be unable to feed sheets or may damage the front ends of the sheets in the case of feeding sheets in a state of a small number of sheets stacked.
When various kinds of sheets having various thicknesses are set on the sheet-mounting surface, it is difficult to eliminate the problems related to sheet feeding through the second separation surface by adjusting the elastic force of the spring that return the second separation surface to the upstream side.
The object of the present invention is to provide a feeding apparatus and printing apparatus that make it possible for a feeding mechanism that uses a first separation surface and a movable second separation surface to perform sheet feeding well for various kinds of sheets.
In a first aspect of the present invention, there is provided a feeding apparatus that feeds a sheet that are stacked in a sheet stacking unit by feeding the sheet by means of a feeding unit and separating the sheet by means of a separation surface; the apparatus comprising: a movable separation surface that is provided so as to be able to move toward a downstream side and an upstream side in a direction in which the sheet is fed by the feeding unit; a pressing unit configured to press the movable separation surface toward the upstream side; and a prevention unit configured to, at a specified position within a range that the movable separation surface moves, prevent the movable separation surface from moving toward at least the downstream side.
With the construction described above, it becomes possible for a feeding mechanism that uses a first separation surface and a movable second separation surface to perform sheet feeding well for various kinds of sheets.
Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).
Embodiments of the present invention will be explained below in detail with reference to the drawings.
In
In
As illustrated in
The knurl 7 is provided so as to be placed in an opening 6a that is provided on the separation surface, and a lower knurl portion that extends below the opening 6a is provided on the knurl 7. The lower knurl portion is formed so as to be integrated with a cam follower 14 that will be described later. Moreover, four pins 11 are provided on the lower knurl portion so as to protrude out from the lower knurl portion. Two guiding sections 9 that are each provided with a guide surface 10 are attached to the rear surface side of the separation surface 6 so as to be on both sides of the lower knurl portion. The four pins 11 of the knurl 7 are set in the guide surface 10 so that the knurl 7 is able to slide along the guide surfaces 10. The guiding surfaces 10 incline downward toward the downstream side in sheet feeding, and therefore the knurl 7 moves so as to retract downward from the separation surface 6 while sliding toward the downstream side. Moreover, the knurl 7 is pressed toward the upstream side by a knurl spring 12. As a result, the initial position of the knurl 7 is at a position that protrudes out further than the first separation surface 6. An upstream side end hook of the spring 12 is provided on a cap 13, and the cap 13 is mounted on the guiding section 9. The elastic force of the knurl spring 12 is set to 100 gf for example so that when the knurl 7 is located on the upstream side, the knurl 7 will not slide to the downstream side under the weight of the sheets when the maximum amount of sheets are mounted in the sheet stacking section. A cam 16 of a cam gear 15 comes in contact with a cam follower 14 of the knurl 7. The cam gear 15 is supported by a bottom case 103 (
The cam 16 of the cam gear 15 comes in contact with the cam follower 14 that is integrated with the knurl 7 to prevent the cam follower 14 from moving to the downstream side. When the cam 16 is at the position shown in
In this embodiment, when the printer is in a standby state, the knurl 7 is in the locked state as illustrated in
When rotating the cam gear 15 again and restricting the position of the knurl 7 further on the upstream side, it is possible to forcibly return the knurl 7 to the initial waiting position by the cam 16 even when it is difficult for the spring to return the knurl 7 due to the position of the plural stacked sheets. Therefore, when the printer is in the standby state, the sheets always return to a position along the feeding tray without dropping down toward the downstream side. Moreover, it is possible, for example, for the pressure applied when the user sets the sheets or for the weight of the sheets itself to prevent the movable knurl from moving toward the downstream side and prevent sheets from being inserted too far toward the back. As a result, it is possible to easily know how far to insert the sheets when setting the sheets, and thus it is possible to improve operability.
In
ROM 106 is a read only memory device that stores various programs such as control programs for the printing apparatus, and the CPU 104 references these control programs in order to execute processing and control that will be described later using
Reference signs 107 and 112 denote motor drivers that are control circuits for controlling the carriage motor 108 and feed motor (LF motor) 17 for performing the printing operation of the serial type inkjet printing apparatus of this embodiment. A reference sign 118 denotes a LF encoder and a reference sign 119 denotes a carriage encoder; where the operating distance and operating speed are detected from respective encoder signals, and the motors are controlled according to feedback to the motors that corresponds to detected signals. A reference sign 120 denotes a cam gear angle phase sensor that detects the angle phase of the cam gear 15.
In STEP 9, the LF motor 17 is continuously driven, and after the sheet has been discharged, the LF motor 17 stops. In STEP 10, it is determined whether or not there is a next page to be printed, and when there is a next page, processing returns to STEP 7, and a sheet is fed. When there is no next page, then in STEP 11, the LF motor 17 is rotated in the reverse direction, and in STEP 12, it is determined whether or not the rotation phase sensor is blocked (OFF), and when the sensor is OFF, then in STEP 13 the LF motor 17 is stopped at the phase after the LF encoder 118 has rotated 20 pulses. Then, in STEP 14 the power is turned OFF and the operation ends.
In the embodiment described above, the knurl was in a locked state at the furthest point on the upstream side, however, the embodiment is not limited to this, and as long as the knurl is in a state of protruding out from the surrounding separation surface 6, at least movement toward the downstream side can be prevented at any position within the movable range.
A second embodiment of the present invention is related to another embodiment of the function of the knurl 7 when feeding a sheet. More specifically, depending on the medium type setting that is set by the user, for sheets that have a low stiffness such as normal paper and that have a small load when being fed, the knurl 7 is in a locked state during feeding of the sheets, and in the case of a medium having high stiffness such as photographic paper, the locked state is released when feeding sheets. As a result, for normal paper which has low resistance when being separated and easily causes the overlap feeding of sheets, it is possible to more surely prevent the overlap feeding of sheets. Moreover, construction is such that when according to the output of a sensor that detects whether or not there are any sheets, it is determined that during printing there are no more sheets, the knurl automatically returns to the locked state in order to supply more sheets, so together with being able to improve the setting characteristics when setting sheets, it is possible to prevent the feeding of overlapping sheets due to sheets slipping and dropping down when setting the sheets.
In
In the case of special paper, then in STEP 7, the LF motor 17 is driven and the cam 16 is rotated 180°. At this phase, the knurl 7 is released from the locked state and is able to move. When it was determined that the sheets are normal paper, processing skips STEP 7 and moves to STEP 8. In the case of normal paper, the feeding operation is performed with the knurl 7 in the locked state as is.
In STEP 8, the LF motor 17 is rotated in the forward direction, which rotates the LF roller and feed roller in the conveyance direction. When there is a sheet, only one sheet is picked up by the operation of the knurl 7 and the separation surface 9, and in STEP 9, the passing of the front end of that sheet is detected by the PE sensor lever unit. When there is no sheet, passage of a sheet is not detected, so it is determined that there is no medium, so in STEP 11, a “No Medium” error occurs, and the error is displayed on the screen of the host computer. In STEP 12, the LF motor 17 is rotated in the reverse direction. As a result, the driving force is transmitted to the cam gear side, and in STEP 13 it is determined whether or not the rotation phase sensor is blocked (OFF), and when it is OFF, in STEP 14 the LF motor 17 stops at the phase after the LF encoder 118 has rotated 20 pulse detections for when the sensor went OFF. At this phase, the knurl 7 is locked at the furthest point on upstream side in the conveyance direction. In STEP 15, after sheets have been supplied, and the reset button has been pressed on the host computer screen, processing returns to STEP 6, and the same routine is repeated.
In STEP 9, when it is determined that the PE sensor is ON, then in STEP 10 a sheet is conveyed to the printing section, and printing is performed by intermittently forwarding the sheet and repeating scanning by the print head. Then, in STEP 16, the LF motor 17 is continuously driven, and after the sheet is discharged, stops. In STEP 17, it is determined whether or not there is a next page to be printed, and when there is a next page, processing returns to STEP 8 and a sheet is fed. When there is no next page, then in STEP 18 the LF motor 17 is rotated in the reverse direction, and in STEP 19 it is determined whether or not the rotation phase sensor is blocked (OFF), and when the sensor is OFF, in STEP 20 the LF motor 17 stops at the phase after the LF encoder 118 has rotated 20 pulses from when the sensor went OFF. Then in STEP 21, the power is turned OFF and the operation ends.
Each of the embodiments above comprises a fixed first separation surface (other separation surface) and a movable second separation surface (movable separation surface), and relates to a form of separating sheets that are fed, however, application of the present invention is not limited to this form. For example, it is also possible for the second separation surface (movable separation surface) to comprise plural knurls 7 and mechanisms for moving or securing the knurls 7 in the direction which cross with the direction that sheets are fed without comprising a first separation surface (other separation surface), and to perform separation by using these plural knurls 7.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2014-029480, filed Feb. 19, 2014, which is hereby incorporated by reference wherein in its entirety.
Number | Date | Country | Kind |
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2014-029480 | Feb 2014 | JP | national |
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