JP2005219860A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that realizes manual sheet feeding without adding a dedicated part.
SOLUTION: When a paper is inserted, a paper insertion slot for manual feeding that can be detected by an existing paper sensor on both sides is provided, and when paper from the paper insertion slot is detected during standby, the refeed position of both sides is set. After the pre-rotation process is completed, the paper is fed again.
[Selection] Figure 1

Description

  The present invention relates to an image forming apparatus such as a laser printer capable of forming images on the front and back sides of a sheet, and manually feeds a sheet having an image formed on one side thereof to a double-sided conveyance unit that inverts and conveys the sheet to an image forming unit. It relates to what has a part.

  In some conventional image forming apparatuses, a sheet on which an image is formed on one side is reversed by the image forming unit and conveyed again to the image forming unit to form an image on the back side of the sheet.

  In an image forming apparatus such as a laser printer, which is an example of such a conventional image forming apparatus, double-sided conveyance that reverses the sheet and conveys it to an image forming unit to a relatively large, high-speed, high-cost apparatus. There is an apparatus in which a double-sided conveyance unit having a path is optionally mounted to record images on both sides of a sheet. In recent years, small, low-speed, low-cost laser printers and the like have been equipped with a function of recording images on both sides of a sheet in order to save resources (see, for example, Patent Document 1).

  In addition to this, the image forming apparatus includes a manual paper feed mechanism for feeding thick paper and OHP that are difficult to feed from the cassette paper feed unit. A low-cost image forming apparatus has a function that can feed only one sheet at a time in order to reduce costs.

As a matter of course, a low-cost image forming apparatus having the above functions is required to have a low cost for all functions.
JP-A-3-89261

  However, if such a manual sheet feeding mechanism is configured independently, the cost increases.

  Accordingly, the present invention has been made in view of such a current situation, and an object thereof is to provide an image forming apparatus capable of realizing a manual sheet feeding mechanism at low cost.

  The present invention includes a reversing conveyance unit that reverses a sheet on which an image is formed on one side by an image forming unit, and a double-side conveyance unit that conveys a sheet that has come out of the reversing unit to the image forming unit again. In the image forming apparatus for performing image formation on the back side of the sheet by conveying the sheet from the double-sided conveyance unit to the image-forming unit again by inverting the sheet by the sheet reverse-conveying unit on which the image is formed A first position sensor is provided at the entrance, a second position sensor is provided at the exit of the double-sided conveyance unit, an insertion port for manual feeding is provided on the back surface of the image forming apparatus, and a conveyance second is provided in the vicinity of the first position sensor. One roller pair is provided, and the first position sensor can detect a sheet inserted from an insertion port for manual sheet feeding.

  Further, according to the present invention, when a sheet inserted from an insertion port for manual sheet feeding is detected by the first position sensor, the first roller pair is rotated to convey the sheet, and when the sheet is detected by the second position sensor, Stop the rotation of one roller pair, stop the conveyance of the sheet, complete the initial processing necessary for image formation, and then rotate the first roller pair again to feed the sheet to the image forming unit. It is a feature.

  Further, the present invention is characterized in that when a sheet inserted from an insertion port for manual sheet feeding is detected by a first position sensor, the sheet is conveyed by rotating the first roller pair when image formation is not being performed. To do.

  The present invention also includes a reversing conveyance unit that reverses a sheet on which an image is formed on one side by the image forming unit, and a double-side conveyance unit that conveys the sheet that has come out of the reversing unit to the image forming unit again. In the image forming apparatus for performing image formation on the back side of the sheet by conveying the sheet from the double-sided conveyance unit to the image-forming unit again by inverting the sheet by the sheet reverse-conveying unit on which the image is formed A first position sensor at the entrance, a second position sensor at the exit of the double-sided conveyance unit, a first roller pair for conveyance in the vicinity of the first position sensor, and a second roller capable of forward and reverse rotation to the reverse conveyance unit A pair is provided, and a third position sensor is provided at an exit portion where the sheet is taken out of the apparatus by the reversing conveyance unit.

  Further, according to the present invention, when the sheet is detected by the third position sensor, the third roller pair is reversely rotated to feed the sheet to the double-sided conveyance unit. In the double-sided conveyance unit, the first position is detected when the sheet is detected by the second position sensor. The rotation of the roller pair is stopped, the conveyance of the sheet is stopped, the initial processing necessary for image formation is completed, and then the first roller pair is rotated again to feed the sheet to the image forming unit. To do.

  Further, the present invention is characterized in that when a sheet is detected by the third position sensor when an image is not formed, the first roller pair is rotated and the sheet is not conveyed.

  According to the present invention described above, an opening (manual insertion port) for inserting a sheet is provided on the back of the main body, and when one sheet is inserted, the leading end of the sheet is detected by the reversal sheet introduction detection sensor S5, 12, the paper is stopped at a predetermined position, and by performing initial processing (pre-rotation processing) necessary for image formation while the paper is stopped, manual feeding can be realized by changing a few members. An image forming apparatus that can be reduced can be provided.

  Further, a manual feed sensor S7 is provided in the face-down paper discharge unit, the paper is detected by the manual feed sensor S7, the paper is stopped at a predetermined position by the pair of reverse paper transport rollers 12, and initial processing necessary for image formation during the stoppage. By performing (pre-rotation processing), it is possible to realize manual paper feeding without adding a manual feed material member and eliminating the manual feed port with the addition of one sensor, which greatly reduces costs. An image forming apparatus can be provided.

(Example 1)
Hereinafter, the form of Example 1 of this invention is demonstrated using drawing.

  FIG. 1 is a diagram illustrating a schematic configuration of a laser beam printer which is an example of an image forming apparatus according to a first embodiment of the present invention.

  In the figure, reference numeral 1A denotes a laser beam printer. The laser beam printer 1A forms a single-side mode in which an image is formed on one side of a sheet P which is a sheet, and an image is formed on the back side of the sheet P on which an image is formed on one side. And double-sided mode. Reference numeral 1 denotes a laser beam printer main body (hereinafter referred to as a main body), 2 denotes a double-sided conveyance unit that includes a double-sided conveyance path R and is detachably attached to the main body 1, and 3 denotes a paper cassette that stores paper P.

  The paper P stored in the paper cassette 3 is fed in the direction of the arrow L1 by the drive of the cassette paper feed roller 3a and the transport roller pair 3b, and then the direction of the arrow L2 by the drive of the transport roller pair 3c. It is conveyed to.

  A laser scanner unit 4 raster-scans the laser beam based on image data from a host computer or the like, which will be described later, and is statically mounted on a photosensitive drum 5a charged in advance by a charger 5b by a folding mirror 4a. It forms an electrostatic latent image. The electrostatic latent image formed on the photosensitive drum 5a is developed with toner by the developing device 5c, and then transferred to the paper P conveyed by the conveying roller pair 3c in the transfer unit 5d.

  Further, the toner image transferred onto the paper is fixed on the paper P by the heat fixing device 6. The heat fixing device 6 includes a heating body (not shown) and a thermistor that detects the temperature of the heating body, and heat and pressure are applied to the paper P after the transfer process to fix the toner image on the paper P. It is configured to let you.

  Reference numeral 7 denotes a pair of paper discharge rollers which are conveying means. The paper P which has passed through the heat fixing device 6 by the paper discharge roller pair 7 is a face-up tray 8 which is a second paper discharge unit or the upper surface of the main body 2. The paper is discharged to a face-down paper discharge unit 9 which is a first paper discharge unit provided in the first. Here, the face-up tray 8 is provided in the main body 1 so as to be openable and closable. When the paper P is discharged in a face-up state, the face-up tray 8 is opened as shown in FIG. It has become.

  On the other hand, when the sheet P is discharged in a face-down state, the face-up tray 8 is closed as indicated by a broken line in FIG. By closing the face-up tray 8 in this way, a transport path for transporting the paper P to the face-down paper discharge unit 9 is secured, and a face-down paper discharge roller pair (hereinafter referred to as an FD paper discharge roller pair). The paper P can be discharged to the face-down paper discharge unit 9 by driving in the direction of the arrow a of 10.

  Further, when performing double-sided printing, the face-up tray 8 is closed and the FD paper discharge roller pair 10 is rotated forward for a predetermined time to convey the paper toward the face-down paper discharge unit 9, and then the FD paper discharge roller pair. 10 is reversely rotated so as to face the double-sided conveyance unit 2.

  Then, the paper P directed to the double-sided conveyance unit 2 in this way is conveyed to the double-sided conveyance path R by the reverse sheet guide roller 11, and the sheet P conveyed further to the double-sided conveyance path R is the reverse sheet conveyance roller pair 12. After the sheet is conveyed in the direction of the arrow L4, the sheet is stopped in front of the reversing sheet refeed roller pair 13 and waits until the sheet is fed again as the second side (back side) sheet for duplex printing. Yes.

  Here, S6 is a re-feed sensor provided in the double-sided conveyance unit 2, and this re-feed sensor S6 indicates that the paper P conveyed on the double-sided conveyance path R has reached a predetermined re-feed position. When detected, a detection signal is output to an engine controller unit 14 which is a control means shown in FIG.

  Then, the engine controller unit 14 stops the reversing paper conveyance roller pair 12 based on the detection signal from the re-feed sensor S6 and makes the paper P stand by at a predetermined re-feed position, and then reverses at a predetermined timing. The paper refeed roller pair 13 is driven. As a result, the paper P waiting in the double-sided conveyance path R is fed again to the image forming unit 5 through the conveyance roller pair 3c, and then, in the same conveyance path as the printing operation from the paper cassette 3 described above. The printing operation for the second side (back side) of double-sided printing is performed, and then the paper is discharged to the face-down paper discharge unit 9.

  In the figure, S1 is a paper sensor for detecting the presence or absence of the paper P in the paper cassette 3, and S2 is a paper feed sensor for detecting the leading edge and the trailing edge of the paper P conveyed by driving the conveying roller pair 3c. Based on the detection signal from the paper feed sensor S2, the engine controller unit 14 determines the image writing timing.

  S5 is a reverse paper introduction detection sensor for detecting the timing when the paper is conveyed to the double-sided conveyance path R and the leading edge and the trailing edge of the paper.

  Further, S3 is a paper discharge sensor that is provided between the face-up tray 8 and the image forming unit 5 and detects that the paper P has passed through the heat fixing device 6.

  As shown in FIG. 3, the manual sheet feeding portion of the present invention has an opening (manual insertion port) for inserting a sheet on the back of the main body, and when one sheet is inserted, the leading end of the sheet is detected by the reverse sheet introduction detection sensor S5. It is like that.

  FIG. 2 is a block diagram of a printer controller unit that controls the series of printing operations described above. This printer controller unit mainly includes an engine controller unit 14 and an image controller unit 15.

  Here, the image controller unit 15 receives the encoded image information (code data) from the host computer 17 or the like via an external interface (not shown), and then converts the code data into video data of a dot image. A print command is sent to the engine controller unit 14 via the illustrated video interface, and video data is sequentially sent to the engine controller unit 14 in synchronization with the main scanning and sub-scanning synchronization signals from the engine controller unit 14. It has been done.

  Further, the engine controller unit 14 drives the rollers such as the refeed roller pair 13, the reversal paper refeed roller pair 13, the transport roller pairs, the reversal paper introduction detection sensor S5, the refeed sensor S6, and other sensors. By monitoring the input from the printer, the printer engine such as the laser scanner unit 4 and the thermal fixing device 6 is controlled in an integrated manner, and the video data from the image controller unit 15 is printed on paper.

  Next, the control operation of the engine controller in the present invention will be described with reference to the flowchart shown in FIG.

After the power is turned on, the engine controller 117 checks whether or not the sheet is detected by the reverse sheet introduction detection sensor S5 through a series of control (main routine) of the engine controller 117. When it is determined that there is a sheet, it is checked whether it is in a standby state. If it is in standby, the sheet detected by the reversed sheet introduction detection sensor S5 is conveyed by driving the pair of reversed sheet conveyance rollers 12. If the paper is not detected by the reverse paper introduction detection sensor S5 and if it is not in standby even if it is detected, the process goes to the main routine. (S201 to S203)
When the conveyed paper is detected by the refeed sensor S6, the conveyance is stopped. Then, the image controller 15 waits for an instruction to manually print one sheet. Upon receipt of the single-sheet manual printing instruction, the engine controller 117 performs initial processing (pre-rotation processing) necessary for image formation. After the initial processing is completed, the reverse paper transport roller pair 12 is driven to feed the paper to the reverse paper refeed roller. By sending the paper to the pair 13, the paper is sent to the image forming unit to perform a printing operation. (S204-S208)
As described above, the manual feed port is provided, the paper inserted into the manual feed port is detected by the reverse paper introduction detection sensor S5, the paper is stopped at a predetermined position by the reverse paper conveyance roller pair 12, and image formation is performed during the stop. By performing the initial processing (pre-rotation processing) necessary for the manual feeding, manual feeding can be realized by adding only the manual feed port without adding a large number of manual feeding members.

  Thereby, significant cost reduction can be achieved.

(Example 2)
Next, a second embodiment of the present invention will be described.

  FIG. 5 is a diagram illustrating a schematic configuration of a laser beam printer which is an example of an image forming apparatus according to the second embodiment of the present invention.

  In the second embodiment, the face-up tray 8 is closed.

  FIG. 6 is a block diagram of a printer controller unit for controlling a series of printing operations. The printer controller unit mainly includes an engine controller unit 14 and an image controller unit 15.

  Description of the same parts as those in the first embodiment is omitted.

  The difference from the first embodiment is that a manual feed sensor S7 is newly provided and the manual feed port 15 is deleted. Thereby, it is not necessary to newly provide a manual feed port only by adding the manual feed sensor S7.

  Next, the operation content of the image forming apparatus according to the second embodiment will be described with reference to the flowchart of FIG.

After the power is turned on, the engine controller 117 checks whether paper is detected by the manual feed sensor S7 by a series of control (main routine) of the engine controller 117. If it is determined that there is a sheet, it is checked whether it is in standby mode. If it is in standby, the sheet detected by the manual feed sensor S7 is conveyed by driving the FD sheet discharge roller pair 10 and the reverse sheet conveyance roller pair 12. If no paper is detected by the manual feed sensor S7 and if it is not in standby even if it is detected, the process goes to the main routine. (S301-S303)
When the conveyed paper is detected by the refeed sensor S6, the conveyance is stopped. Then, the image controller 15 waits for an instruction to manually print one sheet. Upon receipt of the single-sheet manual printing instruction, the engine controller 117 performs initial processing (pre-rotation processing) necessary for image formation. After the initial processing is completed, the reverse paper transport roller pair 12 is driven to feed the paper to the reverse paper refeed roller. By sending the paper to the pair 13, the paper is sent to the image forming unit to perform a printing operation. (S304 to S308)
As described above, the manual feed sensor is provided, the paper is detected by the manual feed sensor S7, the paper is stopped at a predetermined position by the pair of reverse paper conveyance rollers 12, and initial processing (pre-rotation processing) necessary for image formation during the stoppage. By performing the above, manual feeding can be realized by adding one sensor without adding a member for manual feeding significantly.

  Thereby, significant cost reduction can be achieved.

1 is a diagram illustrating a schematic configuration of a laser beam printer that is an example of an image forming apparatus according to a first embodiment of the present invention. FIG. FIG. 3 is a control block diagram of the laser beam printer. The rear view of the said laser beam printer. The timing chart in the said laser beam printer. FIG. 6 is a diagram illustrating a schematic configuration of a laser beam printer that is an example of an image forming apparatus according to a second embodiment of the present invention. FIG. 3 is a control block diagram of the laser beam printer. The timing chart in the said laser beam printer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A Laser beam printer 1 Laser beam printer main body 2 Double-sided conveyance part 5 Image formation part 6 Thermal fixing device 7 Paper discharge roller pair 8 Face up tray 9 Face down paper discharge part 10 FD paper discharge roller pair 11 Reverse paper guide roller pair 14 Engine Controller part P Paper S3 Paper discharge sensor S7 Manual feed sensor R Double-sided conveyance path

Claims (6)

A reversing conveyance unit that reverses the sheet on which an image is formed on one side by the image forming unit;
Having a double-sided conveyance unit that conveys the sheet that has come out of the reversing unit to the image shape unit again,
The sheet on which the image is formed on one side by the image forming unit is reversed by the reverse conveying unit and sent to the double-sided conveyance path, and the sheet is conveyed again from the double-sided conveying unit to the image forming unit to form the image on the back side of the sheet. In the device
Having a first position sensor at the entrance of the duplex transport section and a second position sensor at the exit of the duplex transport section,
It has an insertion port for manual feeding on the back of the image forming apparatus, a first roller pair for conveyance is provided in the vicinity of the first position sensor,
An image forming apparatus configured to be able to detect a sheet inserted from an insertion port for manual sheet feeding by a first position sensor.   In the configuration of claim 1, when the first position sensor detects a sheet inserted from an insertion port for manual sheet feeding, the first roller pair is rotated to convey the sheet, and the sheet is detected by the second position sensor. When detected, the rotation of the first roller pair is stopped, the conveyance of the sheet is stopped, the initial processing necessary for image formation is completed, and then the first roller pair is rotated again to transfer the sheet to the image forming unit. An image forming apparatus that feeds the image.   3. The image forming apparatus according to claim 2, wherein when the first position sensor detects a sheet inserted from an insertion port for manual sheet feeding when image formation is not being performed, the first roller pair is rotated to convey the sheet. An image forming apparatus. A reversing conveyance unit that reverses the sheet on which an image is formed on one side by the image forming unit;
Having a double-sided conveyance unit that conveys the sheet that has come out of the reversing unit to the image shape unit again,
An image forming apparatus that reverses a sheet by a sheet reversing and conveying unit on which an image is formed on one side by an image forming unit, sends the sheet to a duplex conveying path, and conveys the sheet from the duplex conveying unit to the image forming unit again to form an image on the back side of the sheet In
Having a first position sensor at the entrance of the duplex transport section and a second position sensor at the exit of the duplex transport section,
A first pair of rollers for conveyance in the vicinity of the first position sensor;
A second roller pair that can be rotated forward and backward is provided in the reverse conveying section,
An image forming apparatus characterized in that a third position sensor is provided at an exit portion for feeding a sheet out of the apparatus at the reverse conveying section. In claim 4,
When a sheet is detected by the third position sensor, the third roller pair is rotated in the reverse direction to feed the sheet to the double-sided conveyance unit, and when the sheet is detected by the second position sensor in the double-sided conveyance unit, the first roller pair is rotated. Is stopped, the conveyance of the sheet is stopped, the initial processing necessary for image formation is completed, and then the first roller pair is rotated again to feed the sheet to the image forming unit. . 6. In claim 5, when the sheet is detected by the third position sensor when no image is formed, the sheet is conveyed, until the sheet is detected by the second position sensor and the rotation of the first roller pair is stopped. An image forming apparatus that conveys a sheet.

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