JP2008164683A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus designed so that first copying time is shortened by adding control without ejecting paper standing by at a resist roller even when an image is formed on paper different from paper standing by at the resist roller, and without requiring space saving and a configuration change either. <P>SOLUTION: Before a signal for starting image formation is input to a control means from the input means, the control means causes paper to stand by in the position immediately before an entry path extending to the resist roller of a both-sided conveyance means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus having a control function for shortening a first copy time.

  2. Description of the Related Art Conventionally, an image forming apparatus selects and operates one of sheet feeding units corresponding to a plurality of sheet feeding cassettes arranged below the apparatus main body, thereby removing sheets stored in the sheet feeding cassette. The sheet is conveyed to a registration roller above the apparatus main body through a single sheet conveyance path, held by the registration roller, and conveyed to the image forming unit at a predetermined timing. Then, when the sensor detects that the paper has reached the registration roller, the image forming means is operated to form a predetermined image on the paper.

  In the image forming apparatus as described above, the conveyance of the sheet to the recording unit starts after the start key is pressed. However, since the image forming unit and the paper feed cassette are disposed at separate positions, the conveyance path Has a certain distance, and the arrival time of the sheet from the paper feed cassette to the image forming means becomes long, so that the user completes the operation of the image forming apparatus and the image forming apparatus starts the image forming operation. There is a problem that a so-called first copy time becomes longer from the moment until an image-formed sheet is output.

  In order to solve such problems, a method for increasing the paper feeding and conveying speed has been proposed. However, if the speed is increased, the effect of paper slipping is large, the conveying noise is large, the control is complicated, etc. There was a problem.

As a method other than the method of increasing the paper feeding / conveying speed, a method of previously waiting the paper on the registration roller has been proposed. However, the paper stored in the paper feeding cassette is selected and registered through a single paper conveying path. Since a plurality of sheets cannot be conveyed to the registration roller at the same time because they were conveyed to the roller, when forming an image on a sheet different from the sheet waiting on the registration roller, the sheet waiting on the registration roller Is discharged to the outside, and after the next sheet is discharged, the next sheet must be transported from the sheet cassette to the registration roller, and then an image forming operation must be performed, which causes a problem that the first copy time is not shortened. It was.

  In order to solve the above problem, for example, Patent Document 1 provides a plurality of paper feed cassettes and a plurality of paper conveyance paths corresponding to the paper feed cassettes, and sets the first copy time by waiting the paper at a position immediately before the registration roller in advance. It describes how to shorten.

However, the method disclosed in Patent Document 1 requires a number of sheet transport paths corresponding to the number of paper feed cassettes, so that a space for the image forming apparatus is required, and a member for increasing the transport path is also added. However, there is a problem in that the control becomes complicated and further control for switching the transport path is required.
JP 05-77950 A

  The present invention has been made to solve the above-described problems of the prior art, and even when it is desired to form an image on a sheet different from the sheet waiting on the registration roller, the image forming apparatus waits on the registration roller. This eliminates the need for multiple paper paths to the registration rollers, and saves space, does not change the configuration, and shortens the first copy with additional control. A forming apparatus is provided.

  The invention according to claim 1 includes a plurality of paper feeding means, a paper transport path for transporting paper fed from the paper feed means, a transport roller attached to the paper transport path, and the paper transport path A registration roller that feeds the sheet fed from the image forming unit to the image forming unit at a predetermined timing, a duplex conveying unit that performs duplex printing, a control unit that controls the operation of the sheet feeding unit, the conveying roller, and the registration roller, And an input means for inputting a signal to the control means. The control means enters the registration roller of the duplex conveying means before the image formation start signal is inputted from the input means to the control means. The present invention relates to an image forming apparatus characterized by waiting at a position immediately before a road.

  According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein the double-sided conveying unit has a path that does not reverse the sheet.

  According to a third aspect of the present invention, in the image according to the first or second aspect, the double-sided conveying unit has another path provided with a dedicated paper standby position at a position immediately before the entry path to the registration roller. The present invention relates to a forming apparatus.

  According to the first aspect of the present invention, an image forming instruction is output from the input unit by waiting the sheet stored in the sheet feeding cassette in advance immediately before the entry path to the registration roller of the duplex conveying unit. In this case, the first copy time can be shortened because the waiting sheet is immediately fed from the registration roller to the image forming unit. Further, since the paper is made to wait on the double-sided conveying means, the standby paper does not hinder the conveyance of the image forming paper even when image formation is performed on a paper having a different size from the paper on standby. It is possible to form an image without discharging the waiting paper.

  According to the second aspect of the present invention, since there is a path that does not reverse the paper, it is possible to wait for the paper on the same printing surface, and therefore it is possible to feed the back paper to the paper feeding means. Become.

  According to the invention of claim 3, since the double-sided conveying means has another path having a paper-dedicated standby position at a position immediately before the entry path to the registration roller, the paper of a size different from the paper that is waiting Even when images are to be formed on both sides of the paper, the standby paper does not interfere with the image forming paper in the double-sided conveying means, and it is possible to perform image formation on both sides without discharging the standby paper. Become.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of an image forming apparatus according to the invention will be described with reference to the drawings. The description of the same configuration as that of the conventional image forming apparatus is omitted.
FIG. 1 is an overall view of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a sheet conveyance path diagram when the image forming apparatus according to the present invention has a path that does not reverse the sheet. FIG. 3 is an overall view of the image forming apparatus according to the second embodiment of the present invention.

  In FIG. 1, an image forming apparatus 1 according to the present invention includes a paper feeding unit 3, a paper conveyance path 4, a conveyance roller 5, a registration roller 6, a double-sided conveyance unit 9, an input unit, and a control unit.

  The paper feed means 3 is provided with a paper feed cassette that is detachable, and a pickup roller 2 is provided at one end of the paper feed cassette. The paper is fed to the paper transport path 4 by the pickup roller 2. The number of paper feed cassettes in the paper feed means 3 may be singular or plural for different paper sizes.

  A plurality of conveyance rollers 5 are provided in the sheet conveyance path 4 at predetermined intervals. The paper fed from the paper feeding means 3 by the pickup roller 2 and sent to the paper transport path 4 is sent to the registration roller 6 by the transport roller 5.

  The registration roller 6 conveys the sheet fed from the sheet conveyance path 4 or the double-side conveyance unit 9 to the image forming unit 7 at a predetermined timing.

  The double-sided conveyance unit 9 includes a double-sided conveyance path for sending paper again to the image forming unit, a double-sided conveyance roller installed in a plurality of double-sided conveyance paths at predetermined intervals, and a paper reversing unit 11. In the case of duplex printing, a sheet on which an image is formed on one side is guided to the duplex conveying means 9 by a flapper (not shown) after the image is fixed by the fixing roller 8. The paper conveyed by the double-sided conveyance roller is switched back by the paper reversing means 11 and the printing surface is reversed. The sheet whose printing surface is reversed is sent again to the registration roller 6 via the duplex conveying path by the duplex conveying roller. The normal image forming apparatus 1 has a sheet reversing unit 11 for switching back to the double-sided conveying unit 9, but in order to enable the use of a backing paper, the sheet is not reversed to the double-sided conveying unit 9 as shown in FIG. It is more desirable to have a route.

  The input means may be the same as a conventional one such as a start button or a touch panel provided that it is provided in the document feeder 16 and can output an image printing start signal. Usually, it is provided as a start switch on the upper surface of the image forming apparatus main body.

  The control unit controls the operations of the plurality of sheet feeding units, the conveyance roller, and the registration roller. The control unit causes the sheet to stand by immediately before the entry path to the registration roller of the double-sided conveyance unit (hereinafter referred to as a sheet standby position 12).

  The operation of the image forming apparatus 1 having a control function for shortening the first copy according to the present invention will be described below.

  In the image forming apparatus 1 according to the present invention, the user determines the paper size to be waited at the paper standby position 12. In determining the paper size, it is desirable to set a frequently used paper. When double-sided printing is performed on different sizes of paper, it is necessary to retract the standby paper. However, by setting a frequently used paper, the frequency of paper discharge can be kept low.

  When paper is set in the paper feed cassette of the paper feed means 3, before the print start signal is transmitted from the input means to the control means, the control means picks up the paper set by the user to the pickup roller of the paper feed means 3. 2 is operated to supply the sheet to the sheet conveyance path 4. After supplying the sheet to the sheet conveyance path 4, the control unit operates the conveyance roller 5 to convey the sheet to the registration roller 6.

  The sheet conveyed to the registration roller 6 is sent to the image forming unit 7 as it is, but since the image forming signal is not output from the input unit, the sheet is sent to the fixing roller 8 without being formed. The sheet fed to the fixing roller 8 is guided to the duplex transport path of the duplex transport means 9.

  The sheet sent to the duplex conveying path of the duplex conveying unit 9 is switched back once by the switchback unit 11 and conveyed to the sheet standby position 12 of the duplex conveying unit, and an image forming signal is output from the input unit. Wait until (resist). At this time, since the paper standby switch 13 is responding, the control means does not supply a new paper to the paper standby position 13.

In the present invention, as shown in FIG. 2, the double-sided conveyance unit 9 has a path (b path) that does not pass through the switchback unit 11 and can wait at the paper standby position 12 without the printing surface being reversed. Is desirable. The normal image forming apparatus 1 has only the path a in FIG. 2, and the sheet conveyed to the duplex conveying unit 9 is always reversed by the switchback unit 11. For this reason, the printer waits at the paper standby position 12 on the printing surface opposite to the printing surface of the paper set in the paper feeding cassette of the paper feeding means 3, and an image is formed on the opposite surface. The backing paper cannot be supplied to the paper cassette.
On the other hand, if the duplex conveying means 9 has a path b that does not reverse the printing surface, it is possible to wait at the paper standby position 12 on the same side as the paper set in the paper feed cassette of the paper feed means 3. This is because an image can be formed on the same surface, and the back paper can be supplied to the paper feed cassette of the paper feed means 3.

  When the user changes the paper size to be waited at the paper standby position 12, the control unit discharges the paper waiting at the paper standby position 12, and the newly set size paper is discharged to the paper standby position 12. To wait.

When an image forming signal is output from the input unit on a paper of the same size as the paper waiting at the paper standby position 12, the control means that has received the output signal for image formation operates the registration roller 6 to wait for the paper. The paper waiting at the position 12 is sent to the image forming unit 7 at a predetermined timing. Since the paper waiting at the paper standby position 12 is immediately sent to the image forming means 7, the image forming operation can be performed from the stage of scanning the original with the optical unit, and the first copy time is shortened.
When performing the image forming operation continuously for a plurality of sheets, the control unit does not transfer the second and subsequent sheets to the double-sided conveying unit 9 and does not pass through the sheet standby position 12 in the same manner as a normal image forming apparatus. Perform image formation. In other words, the control unit feeds the sheet fed to the sheet feeding unit 3 to the sheet conveyance path 4 by the pickup roller 2 and directly conveys the sheet from the registration roller 6 to the image forming unit 7 to form an image. The sheet on which the image is formed is fixed by the fixing roller 8 and then discharged.

  On the other hand, when the image forming signal is output from the input unit with a paper having a size different from that of the paper waiting at the paper standby position 12, the control unit that receives the image forming output signal is the same as the normal image forming apparatus. Then, image formation is performed. That is, the control means feeds the paper fed to the paper feed cassette of the paper feed means 3 to the paper transport path 4 by the pickup roller 2, and directly transports the paper from the registration roller 6 to the image forming means 7 to form the image. I do. The sheet on which the image is formed is fixed by the fixing roller 8 and then discharged. At this time, the paper waiting at the paper standby position 12 remains in the standby state, but does not interfere with the image formation because it is on standby at the double-sided conveying means 9 and is discharged to the outside for retraction. There is no need to be done.

However, when an image forming signal for double-sided printing is output from the input unit on a paper having a different size from the paper waiting at the paper standby position 12, the paper standby position 12 is waited to use the double-sided conveyance means 9. The paper that is present hinders image formation. Therefore, in this case, the control device discharges the paper waiting at the paper standby position 12 to the outside first, and then forms an image in the same manner as in double-sided printing in a normal image forming apparatus. That is, the control means feeds the paper fed to the paper feed cassette of the paper feed means 3 to the paper transport path 4 by the pickup roller 2, and directly transports the paper from the registration roller 6 to the image forming means 7 to form the image. I do. The paper on which the image has been formed is fixed by the fixing roller 8 and then guided to the double-sided conveying means 9 by a flapper (not shown). After the printing surface is reversed by the switchback unit 11 of the double-sided conveying unit, the sheet is fed again to the registration roller 6, and the image is formed on the other side by the image forming unit 7 and fixed by the fixing roller 8. After that, it is discharged outside.
After the completion of double-sided printing, the control device again waits for the paper set by the user at the paper standby position 12.

  Note that the image apparatus 1 according to the present invention can be suitably used by incorporating the control means according to the present invention into an existing image forming apparatus when the first embodiment does not have a path in the direction b.

FIG. 3 is a diagram showing a second embodiment of the image forming apparatus 1 according to the present invention. The present embodiment is different from the above embodiment only in that another path having a sheet standby position 15 is provided immediately before the entry path of the double-sided conveying means 9 to the registration roller. Are the same.
Therefore, the present embodiment is the same as the above in that the user sets standby sheets in advance.

  When paper is set in the paper feeding cassette of the paper feeding means 3, the control means sends the paper set by the user to the double-sided conveyance path of the double-sided conveying means 9 before the input means outputs a print start signal to the control means. The point to be guided to is the same as in the first embodiment.

  The sheet conveyed to the duplex conveying path of the duplex conveying means 9 is conveyed to the switching guide 14 in FIG. 3 via the a path or b path in FIG. If no paper is waiting at the paper standby position 15 and the paper standby switch 13 is not responding, the switching guide 14 has another path (c direction) provided with the paper standby position 15 to wait for the paper. Guide the paper to the front. The sheet conveyed to the other path is waited at the sheet standby position 15 and the sheet standby switch 13 reacts, whereby the switching guide switches the double-sided conveyance path to the registration roller direction (d direction).

  When an image forming signal is output from the input means with a paper of the same size as the paper waiting at the paper standby dedicated position 15, and with a paper of a size different from the paper waiting at the paper standby dedicated position 15 When an image forming signal for single-sided printing is output from the input means, the second embodiment is the same as the first embodiment.

  The second embodiment is characterized in that another path is provided in the double-sided conveyance path of the double-sided conveying means 9 as shown in FIG. With this configuration, even when an image forming signal for duplex printing is output from the input unit on a sheet of a size different from that of the sheet waiting at the sheet standby dedicated position 15, the duplex conveying path of the duplex conveying unit 9 is provided. Since the paper is not kept waiting, double-sided printing is not hindered, and the paper waiting at the paper standby dedicated position 15 is not discharged to the outside.

  The present invention is preferably used for an image forming apparatus that shortens the first copy time.

1 is an overall view of an image forming apparatus according to a first embodiment of the present invention. FIG. 5 is a sheet conveyance path diagram when the image forming apparatus according to the present invention has a path that does not reverse the sheet. 1 is an overall view of an image forming apparatus according to a second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 3 Paper feed means 4 Paper conveyance path 5 Conveyance roller 6 Registration roller 9 Double-sided conveyance means 12 Paper standby position 13 Paper standby switch 14 Switching guide 15 Paper standby exclusive position

Claims (3)

Forming a plurality of paper feeding units, a paper conveyance path for conveying the paper fed from the paper feeding means, a conveyance roller attached to the paper conveyance path, and a sheet fed from the paper conveyance path A registration roller to be fed to the means at a predetermined timing; a duplex conveying means for performing duplex printing; a control means for controlling the operation of the sheet feeding means, the conveyance roller and the registration roller; and an input for inputting a signal to the control means Consisting of means,
The control unit causes the sheet to wait at a position immediately before the entry path to the registration roller of the double-sided conveyance unit before an image formation start signal is input from the input unit to the control unit. Forming equipment. The image forming apparatus according to claim 1, wherein the duplex conveying unit has a path that does not reverse the sheet.   3. The image forming apparatus according to claim 1, wherein the double-sided conveyance unit has another path having a dedicated sheet standby position at a position immediately before the entry path to the registration roller.

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