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EP-4737365-A1 - PRINTER

EP4737365A1EP 4737365 A1EP4737365 A1EP 4737365A1EP-4737365-A1

Abstract

To prevent or suppress the occurrence of double feed and eliminate double feed and also prevent or suppress the occurrence of continuous feeding of paper, a printer (100) includes a pickup roller (81) and a feed roller (82) that are fixed to a body of printer (100) and rotate synchronously; a paper tray (20) that stores a plurality of sheet papers (S) and moves a hopper (21a) up and down, the hopper being a part of bottom plate (21); a retarding roller (84) that contacts the feed roller (82) and transports paper (S) stored in paper tray (20) such that the paper (S) is sandwiched between the retarding roller (84) and the feed roller (82), with the paper tray (20) attached to the body of printer (100); and a control portion (90) that controls operations of the pickup roller (81), the feed roller (82), and the hopper (21a). The control portion (90) performs a double-feed elimination process, a continuous-feed prevention process, and a main feed process.

Inventors

  • INOKUCHI, YUTAKA

Assignees

  • Citizen Systems Japan CO., LTD.

Dates

Publication Date
20260506
Application Date
20240520

Claims (8)

  1. A printer comprising: a pickup roller and a feed roller that are fixed to a body of the printer and are configured to rotate synchronously; a paper tray that is configured to store a plurality of sheet papers and to move a hopper up and down, the hopper being a part of a bottom plate of the paper tray; a retarding roller that is configured to contact the feed roller and to transport sheet paper stored in the paper tray such that the sheet paper is sandwiched between the retarding roller and the feed roller, with the paper tray attached to the body of the printer; and a control portion that is configured to control operations of the pickup roller, the feed roller, and the hopper, wherein the control portion is configured to perform: (1) a double-feed elimination process, the double-feed elimination process performed by rotating the pickup roller in a forward rotational direction corresponding to a forward direction of the paper to feed the topmost paper in the forward direction, and feed the topmost paper in the forward direction while being sandwiched between the feed roller and the retarding roller, thereby separating a second paper, fed in an overlapped condition with the topmost paper, from the topmost paper; (2) a continuous-feed prevention process, which is performed after the double-feed elimination process, the continuous-feed prevention process performed by rotating the feed roller in a reverse rotational direction, which is opposite to the forward rotational direction, while the hopper is lowered, thereby separating the second paper from the retarding roller; and (3) a main feed process, which is performed after the continuous-feed prevention process, the main feed process performed by rotating the feed roller in the forward rotational direction, thereby feeding the topmost paper.
  2. The printer according to claim 1, wherein the control portion is configured to perform (0) a separation process before the double-feed elimination process, the separation process being performed by raising the hopper so that the topmost paper stored in the paper tray is brought into contact with the pickup roller, and rotating the pickup roller in a reverse rotational direction, which corresponds to a direction opposite to the forward direction of the paper, thereby making a separation between the topmost paper and the second paper.
  3. The printer according to claim 1, wherein the control portion is configured to perform (4) a vibration process after the continuous-feed prevention process and before the main feed process, the vibration process being performed by raising and lowering the hopper,
  4. The printer according to claim 3, wherein the control portion is configured to perform (5) a standby process after the vibration process and before the main feed process, the standby process being performed by standing by with no operation for a predetermined time.
  5. The printer according to claim 2, wherein the control portion is configured to perform (6) a backlash adjustment process after the separation process, and before the double-feed elimination process, the backlash adjustment process being performed by idling the pickup roller and the feed roller in the forward rotational direction while the hopper is lowered.
  6. The printer according to any one of claims 1 to 5, further comprising a paper sensor that is configured to detect a front end portion in the forward direction of the paper fed in the forward direction with the paper sandwiched between the feed roller and the retarding roller, wherein the control portion is configured to perform: (7) a retry process, the retry process being performed when the paper sensor does not detect the front end portion of the topmost paper in a condition that the topmost paper is fed by a predetermined distance in the forward direction while being sandwiched between the feed roller and the retarding roller in the double-feed elimination process, and the retry process being performed by stopping the rotation of the feed roller, lowering the hopper, and rotating the feed roller in the reverse rotational direction, thereby returning the topmost paper to the paper tray; and wherein the control portion is configured to further perform the double-feed elimination process, the continuous-feed prevention process, and the main feed process after the retry process.
  7. The printer according to claim 6, wherein the control portion is configured to perform a vibration process after the topmost paper is returned to the paper tray in the retry process, the vibration process being performed by raising and lowering the hopper.
  8. The printer according to claim 1, further comprising a paper sensor that is configured to detect a front end portion in the forward direction of the paper fed in the forward direction with the paper sandwiched between the feed roller and the retarding roller, wherein the control portion is configured to perform: (7) a retry process, the retry process being performed when the paper sensor does not detect the front end portion of the topmost paper in a condition that the topmost paper is fed by a predetermined distance in the forward direction while being sandwiched between the feed roller and the retarding roller in the double-feed elimination process, and the retry process being performed by stopping the rotation of the feed roller, lowering the hopper, and rotating the feed roller in the reverse rotational direction, thereby returning the topmost paper to the paper tray; and wherein the control portion is configured to further perform the double-feed elimination process, the continuous-feed prevention process, and the main feed process after the retry process.

Description

[Technical Field] The present invention relates to a printer. [Background Art] Printers include paper trays that are pulled from the body. The paper tray stores a plurality of stacked sheet papers cut to a predetermined size (hereinafter referred to as "papers"). The printer's body includes a pickup roller and a feed roller that rotate in contact with the topmost paper of a plurality of papers stored in the paper tray, thereby feeding that paper into a paper feed path. When the paper is fed by the pickup roller and the feed roller, double feed may occur in which the second paper stacked directly beneath the topmost sheet (paper arranged next to the topmost paper) is fed together with the topmost paper due to static electricity or other factors in a condition that the second paper overlaps the topmost paper. If such double feed occurs, it may cause a paper jam in the paper path downstream or cause misalignment in printing in the printing portion. Thus, to eliminate double feed, a retarding roller is provided to face and contact the feed roller and then feed the paper sandwiched between the feed roller and the retarding roller. In this case, the topmost paper in contact with the feed roller is fed by receiving torque from the feed roller. The retarding roller applies torque in the direction opposite to the feed direction of the feed roller, thereby stopping the second paper that has advanced with the topmost paper in an overlapping manner, separating it from the topmost paper, and eliminating double feed. Here, when the second paper is kept in contact with the retarding roller, the second paper is brought into contact with the feed roller when the topmost paper has left the feed roller, thereby feeding the second paper. This results in continuous feeding, in which the second paper is fed without a sufficient interval from the topmost paper fed earlier. Since the interval between the papers is insufficient, the continuous feeding makes it difficult to control the preset transport or printing. Thus, to avoid the continuous feeding, there have been proposed techniques that ensure a sufficient interval between the topmost paper and the second paper by cutting off the drive force to the feed roller or by reversing the feed roller to send the second paper backward (see, for example, Patent Literatures 1 and 2). [Prior Art Documents] [Patent Literature] [Patent Literature 1] Japanese Patent Application Publication No. H6-250475[Patent Literature 2] Japanese Patent No. 4046993 [Summary of Invention] [Problem to be solved] However, the techniques disclosed in the above patent literatures do not return the second paper to its state prior to the double feed. Thus, when the second paper has stopped immediately after leaving the retarding roller, its transport may start when the front end of the second paper slightly touches the feed roller. The present invention is made in view of the situation. Its object is to provide a printer that can prevent or suppress the occurrence of double feed, eliminate double feed by reliably returning the double-fed second paper to its state before the double feed, even when such double feed has occurred, and also prevent or suppress the occurrence of continuous feeding of the paper. [Solution to Problem] The present invention provides a printer. The printer includes a pickup roller and a feed roller that are fixed to a body of the printer and are configured to rotate synchronously; a paper tray that is configured to store a plurality of sheet papers and to move a hopper up and down, the hopper being a part of a bottom plate of the paper tray; a retarding roller that is configured to contact the feed roller and to transport sheet paper stored in the paper tray such that the sheet paper is sandwiched between the retarding roller and the feed roller, with the paper tray attached to the body of the printer; and a control portion that is configured to control operations of the pickup roller, the feed roller, and the hopper. The control portion is configured to perform (1) a double-feed elimination process, the double-feed elimination process performed by rotating the pickup roller in a forward rotational direction corresponding to a forward direction of the paper to feed the topmost paper in the forward direction, and feed the topmost paper in the forward direction while being sandwiched between the feed roller and the retarding roller, thereby separating a second paper, fed in an overlapped condition with the topmost paper, from the topmost paper; (2) a continuous-feed prevention process, which is performed after the double-feed elimination process, the continuous-feed prevention process performed by rotating the feed roller in a reverse rotational direction, which is opposite to the forward rotational direction, while the hopper is lowered, thereby separating the second paper from the retarding roller; and (3) a main feed process, which is performed after the continuous-feed prevention proces